nonlinear site response evaluation procedure under the

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The 1 st International Applied Geological Congress, Department of Geology, Islamic Azad University - Mashad Branch, Iran, 26-28 April 2010

Nonlinear Site Response Evaluation Procedure Under The Strong Motion (Case Study: Miyaneh-Azarbayjan Sharghi Province-Iran)

Abbas Abbaszadeh shahri *, Bijan Esfandiari2, Hosein Hamzeloo 3, Reza Esmaeiabadi4

* Invited staff of Islamic Azad University of Damavand branch, Department of geophysics, Islamic Azad University of Hamedan branch, [email protected].

2-Professor of Engineering Faculty of Tehran University, Tehran, Iran

3- Associated professor of International Institute of earthquake Engineering and Seismology 4-Academic staff of Civil engineering Department, Islamic Azad University of Rudehen branch

Abstract The Miyaneh city and its suburban areas are located in the Northwest of Iran in Azarbayjan-Sharghi province. This area is prone to high seismic risk due to the presence of several active faults. Subsurface soils subjected to strong motion exhibit significant nonlinear behavior. In this paper a case study on ground response analysis of a site in Miyaneh region during the Ardabil earthquake (28 Feb. 1997, Mw6.1) is presented. For site characterization, deep site investigations have been undertaken, and a seismic geotechnical procedure for the proposed bridge over the rivers at mentioned site which is performed for Iran railway network, subjected to earthquake provokes has been notified and, the effect of nonlinearity on site response analysis for the selected site with assumption of elastic and rigid (viscoelastic) half space bedrock by use of Standard Hyperbolic Model nonlinear approach was evaluated and the results of them were compared to each other. Test of the capability of designed computer code by authors, namely as “Abbas Converter”, description and evaluating the nonlinearity of the subsurface soil conditions encountered at the sites to analyze, evaluate the obtained test, site response and quantify the site effect on the surface over a number of geotechnical areas were the targets of this study. The results clearly showed that the effect of bedrock and local soil conditions on soil behavior under the earthquake excitation is one of the main effective factors on computed response spectra in ground response prediction. The key factor in this work was to develop and use “Abbas Converter”. It worked and install so quickly, operated as a logic connecter function between the used softwares and could generate the input data corresponding to defined format for them. Its output results easily can export to the other used softwares in this study. More than it can make and render the study easier than previous have done, and take over the encountered problem. Keywords: Miyaneh city, “Abbas Converter”, Ardabil earthquake, site response, site amplification 1. Introduction The Miyaneh region with 47˚, 30΄ to 48˚ East longitude and 37˚ to 37˚, 30΄ North latitude is placed on Northwest of Iran in Azarbayjan-Sharghi province. This area is an active seismic belt which is located in Alborz-Azarbayjan seismotectonic province. The Ardabil earthquake with Mw 6.1, Depth of 10 Km and 38.075 N, 48.050 E epicentral coordinates, occurred at 4:27 p.m. Iran standard time and lasted for 15 seconds was a destructive earthquake that occurred on 28 Feb. 1997. The epicenter was located near the city of Ardabil in northeastern Iran. In this study by use of geological, geophysical and geotechnical data with a designed

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computer code by authors namely as “Abbas Converter” the response spectra, computed motion and some related parameters for the selected area were evaluated and compared. 2. Local Geology and Ground Response The local soil conditions have profound influence on ground response during earthquakes and can not be ignored. This problem is commonly referred to as a site specific response analysis or soil amplification study. Site response analysis is commonly performed to estimate and characterize site effects by solving the dynamic equations of motion via an idealized soil profile. Use a wide database of recorded strong motions and to group accelerograms with similar source, path and site effects could be the ideal solution for such a problem, which in practice such a database is not available. An alternative way for taking over to this problem is based on computer codes, developed from the knowledge of the seismic source process and of the propagation of seismic waves, that can simulate the ground motion associated with the given earthquake scenario. Superficial deposits, topography and basin effects, ground failure and structural deficiencies, profile depth, dynamic stiffness, impedance ratio between the soil deposit and underlying bedrock, the material damping of the soil deposits, nonlinear response of a soft potentially liquefiable soil deposits, soil type, cementation and geologic age, frequency of the base motion, the geometry and material properties of both bedrock and deposited soils, horizontal extent of the soil deposits overlying bedrock, slopes of the bedding planes of the soils overlying bedrock and faults crossing the soil deposits are some of the soil conditions and local geological features affecting the ground response. 3. Analysis Method Characterization of site based on field investigation and laboratory tests, elect and apply the rock motion (natural or synthetic acceleration time history) on soil profile column associated with seismotectonic structure as input for rigid and elastic half space bedrock to represent and compute the effect of site motion on the soil profile at the surface are the analysis method steps. Because of the limitation in software applicability, no software can reply to all requested parameters lonely and our study respectively. For this reason the authors forced to produce a computer code to generate the new data and motion for used softwares corresponding to seismotectonic of selected area and convert the primary input of them to the other. Work and installing so quickly, operating as a logic connecter link between the used softwares and ability to generate the input data correspond the defined format for them are some of the advantages of this code. More that, its output can easily export to the other used software in this study. This code make and render easy the study more than previous have done and with it, the authors could enter recorded data with different format as an input and take defined format for them. Based on the calculated hypocentral distance, the L component of Ardabil event was applied on the bottom of the soil profile as shown in figure1 and the proposed steps of this study are shown in figures 2 to 4. This procedure indicated that the designed code can work with different conditions and shows its abilities. Among a total of 28 drilled bore holes, 10 borelogs were carefully evaluated, but the results of two of them with minimum 40m depth (BH1 and BH10) were select and presented in figures 5 to 9. Soil profile as shown in table (1), for comparison must be created and modified. In view of this, no attempts were made for developing the regression correlation based on the entire dataset and N values from locations where tests were conducted. In this study 180 pairs of N value and Vs

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were applied and a formula which explained Vs as a function of N value by use of “Abbas Converter” was determined as Vs=160.16+0.42N for the selected area. By comparison of the above figures the results can under take and summarize in tables (2) and (3). 4. Discussion and Conclusion This study tried to follow in conducting a meaningful site response and amplification study thus a case study on ground response analysis of a site in Miyaneh city, during the Ardabil earthquake is presented. The study shows that the Measurement and prediction of ground vibration due to strong motion have demonstrated the predominant role of site effects in the response of infrastructure during a seismic event. Site response analysis is usually the first step of seismic geotechnical study and authors have been trying to find a practical and appropriate solution for ground response analysis under earthquake forces for the selected site. Determination of the site specific ground response analysis is the aim of this effect of local soil conditions on seismic waves amplification and hence estimating the ground response spectra for future design purposes. The amplification spectrum of the soil column is computed between the top and the bottom of this soil deposit. Borings and dynamic in situ tests with the aim to evaluate the soil profile of Vs have been performed. The results show a very detailed and stable Vs profile. The obtained Vs profile has a good comparative with other insitu tests. After evaluating the accelerograms at the bedrock, the ground response analysis at the surface, in terms of time history and response spectra, has been obtained by nonlinear standard hyperbolic model. The PGA value at the ground surface obtained from the used computer codes which ranged from 1.1g to 0.57g can use to prepare the PGA map of Miyaneh. They are not distributed uniformly due to variation in the soil profile at various locations, more that this PGA is comparable to obtained PHA values using SPT data and the shape of variation of PA with depth are similar to the SPT data. The calculated amplification factor ranged from 3.56 to 4.30 in elastic and 34.9 to 56.4 in rigid conditions can be used to prepare the amplification map of Miyaneh region. 5. References

1-Anbazhagan, P., 2007, Site characterization and seismic hazard analysis with local site effects for microzonation of Bangalore, research work at the Indian Institute of Science, Dept. of Science and Technology of the Government of India.

2- Arslan, H., Siyahi, B., 2006, A comparative study on linear and nonlinear site response analysis, Environ. Geol., 50: 1193-1200.

3- Borja, R.I., Chao, H.Y., Montas, F.J. and Lin, C.H., 1999, Nonlinear ground response at Lotung LSST site, Journal of Geotech. Geoenviron. Eng., 125(3): 187-197.

4- Boominathan, A., 2004, Seismic site characterization for nuclear structures and power plants, Curr. Sci. (87), 1384-1397.

6- Elgamal, A.W., Zeghal, M., Parra, E., Gunturi, R., Tang, H.T. and Stepp, J.C., 1996, Identification and modeling of earthquake ground response I. Site amplification, Soil Dyn. Earthquake Engg. 15, 499-522.

7- Field EH, Johnson PA, Bersenev IA and Zeng Y (1997) Nonlinear ground motion amplification by sediments during the 1994 Northridge earthquake. Nature, 390: 599-602.

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8- Idriss, I.M., 1990, Response of soft soil sites during earthquakes, Proceedings of the symposium to Honor H.B. Seed, Berkeley, CA, 273-289.

9- Imai, T., Tonouchi, K., 1982, Correlation of N-value with S-wave velocity, Proc. 2nd Euro. Symp. on Penetration Testing, 67-72.

10- Joyner, W.B., Chen, A.T.F., 1975, Calculation of nonlinear ground response in earthquake, BSSA, 65: 1315-1336.

11- Lam, N., Wilson, J., Chandler, A. and Hutchinson, G., 2000, Response spectrum modeling for rock sites in low and moderate regions combining velocity, displacement and acceleration predictions, Earthquake Engineering and Structural Dynamics, 29: 1491-1525.

12- Mersi, G., Febres-Cordero, E., Sheilds, D.R., Castro, A., 1981, Shear stress-strain –time behavior of clays, Geotechinique, 31(4), 537-552.

13- Park, D. and Hashash, Y.M.A., 2004, Soil damping formulation in nonlinear time domain site response analysis, Journal of Earthquake Engineering, Vol. 8, No.2, 249-274.

14- Rodriguez-Marek, A., Bray, J.D. and Abrahamson, N.A., 2000, A geotechnical seismic site response evaluation procedure, In Proceeding of 12 WCEE, Auckland, New Zealand.

15- Rolling, K.M., Evans, M.D., Diehl, N.B., Daily, W.D., 1998, Shear modulus and damping relationships for gravel, J. Geotech. Geoenv. Engg., ASCE 124, 396-405.

16- Seed, H.B., Idriss, I.M., 1970, soil moduli and damping factors for dynamics response analysis, Report No. EERC70-10, University of California, Berkeley.

17- Seed, H.B., Murarka, R., Lysmer, J., Idriss, I.M., 1976, Relationships between maximum acceleration, maximum velocity, distance from source and local site conditions for moderately strong earthquakes, BSSA, 66 (4), 1323-1342.

18- Vucetic, M., 1990, Normalized behavior of clay under irregular cyclic loading, Canadian Geotechnical Journal, 27, 29-46.

19- Vucetic, M., Dobroy, R., 1991, Effect of soil plasticity on cyclic response, Journal of Geotechnical Engineering, 117(1), 87-107.

20- Yoshida, N. and Iai, S., 1998, Nonlinear site response analysis and its evaluation and prediction, In: 2nd international symposium on the effect of surface geology on seismic motion, Yokosuka, Japan, pp.71-90.

Figure1. L Component of Ardabil event (PGA=1.1447g at t=20.66s)

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Figure2. Proposed method for this study by authors

Figure3. Ability of “Abbas converter” to install in parallel condition

Figure4. Testing program steps

Testing program

Field test

Laboratory test

Field density, moisture content, SPT and standard load tests

Specific gravity, Atterburg limits, sieve analysis, direct shear tests and chemical analysis, reclassified in laboratory according to USCS

Propose and develop the idealized soil profile

Corrected SPT & N value Evaluation of shear modulus

Obtained data and information

Characterization of Vs, soil damping and their variations for each layer at the selected site

Determination of: 1) bedrock depth in each borelog 2) Engineering characteristics for the site response study

New Input Data

Abbas Converter

Abbas Converter

Abbas Converter

Defined input (Seismosignal)

Defined input (Proshake)

Defined input (UIUC)

Output

Output

Output

Abbas Converter Input Curve Expert & Matlab

Final output

New Input data

Seismosignal Output

Abbas Converter Input

Proshake

Output Abbas Converter

Input UIUC

OutputAbbas Converter

Input

Curve Expert & MATLAB Final Output

Abbas Converter

Site Investigation (Characterization)

Results

LisCAD v6.2

Log2.1

Geotechnical map

Geological map

Insitu tests

Physical section

Mechanical section

Results +Recorded data

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Table (1): Soil profile of BH10 and BH1

Comparison between Input and Computed motion in Elastic and Rigid Half space

0

0.05

0.1

0.15

0.2

0.25

0 10 20 30 40 50 60 70 80 90

Time(s)

Acc

eler

atio

n(g)

Input motion-BH10-Elastic half space

Computed motion-BH10-Elastic halfspaceInput motion-BH10-Rigid half space

Computed motion-BH10-Rigid halfspaceComputed motion-BH1-Elastic halfspaceComputed motion-BH1-Rigid halfspace

Figure5. Comparison between the Input and Computed motion in Elastic and Rigid half space (5% damping)

Comparison between Input and Computed response in Elastic and Rigid half space

0

0.2

0.4

0.6

0.8

1

1.2

1.4

0 1 2 3 4 5 6 7 8 9 10

Period(s)

PSA

(g)

Input response-BH10-Elastic half space

Computed response-BH10-Elastic halfspaceInput response-BH10-Rigid half space

Computed response-BH10-Rigid halfspaceInput response-BH1-Elastic half space

Computed motion-BH1-Elastic

Computed motion-BH1-Rigid

Input response-BH1-Rigid

Figure6. Comparison between Input and Computed

response in Elastic and rigid half space (5% damping)

Soil type

Depth(m) Thickness(m) γ(gr/cm3) SPT PI Vs(m/s)

CL 1.5 1.5 1.55 37 23 244.926 SC 1.5 1.5 1.53 29 12 230.95 SC 3.5 2 1.53 46 17 270.466 GP 3.5 2 1.77 43 --- 265.603 CL 12 8.5 1.62 55 20 292.04 SP-SM

7.5 4 1.8 88 --- 368.022

SM 14.5 2.5 1.7 65 --- 319.19 CL 31.5 24 1.78 53 14 287.629 CL 16.5 2 1.73 59 22 300.618 CL 33.5 2 1.82 78 10 337.499 SM 18.5 2 1.71 73 30 328.326 GC 36 2.5 1.85 66 12 319.1 CL 20.5 2 1.68 60 23 305.455 CL 40 4 1.9 70 17 322.651 CH 24.5 4 1.73 58 18 298.506 MH 26.5 2 1.71 72 27 326.44 CL 30.5 4 1.81 54 25 289.849 CH 32.5 2 1.71 61 27 301.1 CL 44.5 12 1.84 73 21 368.326

BEDROCK γ(2.0gr/cm3), Vs=1016.125m/s (BH10) BEDROCK γ(2.21gr/cm3), Vs=1214.2m/s (BH1)

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Amplification Ratio

0

10

20

30

40

50

60

0 5 10 15 20 25

Frequency(Hz)

Four

ier A

mpl

ifica

tion(

g-s)

BH10-Rigid half space

BH10-Elastic half space



Spectral Acceleration

0

10

20

30

0 2 4 6 8 10

Period(s)

Spec

tral

Acc

eler

atio

n(g)


Bh10-Elastic half space



Figure7. Amplification ratio spectrum Figure8. Spectral Acceleration spectrum

Table (2): Rigid half space parameters Location Parameter Maximum

at…(Input) Maximum at…(Computed)

BH-10 motion 0.2153g (t=24.1s) 0.0635g (t=39.1s) BH-10 Response spectra PSA=1.345 (Period

0.54s) PSA=0.3986g (Period 0.61s)

BH-1 motion 0.2153g (t=24.1s) 0.0502 (t=37.08s) BH-1 Response spectra PSA=1.171g (Period

0.54s) PSA=0.2963g (Period 0.56s)

BH-10 Amplification ratio --------------------------- 56.4 (f=1.9274Hz) BH-1 Amplification ratio --------------------------- 34.9(f=1.9146Hz) BH-10 Spectral Acceleration --------------------------- 26.1g (period 0.52s) BH-1 Spectral Acceleration --------------------------- 8.22g (period 0.65s)

Table (3): Elastic half space Parameters

Location Parameter Maximum at…(Input)

Maximum at…(Computed)

BH-10 motion 0.2027g (t=24.1s) 0.0619g (t=39.1s) BH-10 Response spectra PSA=1.237g (Period

0.54s) PSA=0.3842g (Period 0.55s)

BH-1 motion 0.2027g (t=24.1s) 0.0619g (t=39.1s) BH-1 Response spectra PSA=1.112 (Period

0.54s) PSA=0.2936g (Period 0.55s)

BH-10 Amplification ratio --------------------------- 3.56 (f=1.8889Hz) BH-1 Amplification ratio --------------------------- 4.30 (f=1.8889Hz) BH-10 Spectral Acceleration --------------------------- 4.91g (period 0.53s) BH-1 Spectral Acceleration --------------------------- 5.79g (period 0.52s)

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Deciphering groundwater potential zones in sand stone terrain Based on GIS applications

(Case study: Masjed-e- Soleiman, Iran)

N. Kalantari1· A. Khoobyari*2·A. Charchi1·M.R. Keshavarzi1

1Geology department of Shahid Chamran University, Iran

2 Ms.c student (hydrogeology) Shahid Chamran University, Iran E- Mail address: [email protected]

Abstract The study area is situated about 100 km in the north east of Ahwaz in the southwest of Iran. The Aghajari sand stone formation covers about 70% of the study area and water demand of the inhabitants are mainly met by springs rising up from the same formation. The aim of this investigation is to find out the most favorable places in this formation for well divining to meet domestic purposes. The field collected data indicated that in places where the sand stone layer is thick, fractures well developed, slope is gentle and soil cover is thin; springs with higher discharge were noticed.. In the present study, the foregoing parameters including; sand stone layer, joint and fracture, soil cover, springs and slope were converted into GIS layers. Then, according to field observations rating was carried out and based on GIS map groundwater potential zones was determined. Key words: Deciphering potential zones, ground water, sand stone, GIS Introduction Due to location of Iran in arid and semiarid climatic zone the average annual rainfall is about 240 mm and overall water resources is limiting. An important source of water supply in Iran is groundwater but as a result of low rainfall promising aquifers are also limited. On the other hand the annual water consumption in Iran exceeds 130 BCM and groundwater contribution in some circumstances passes 50% of the total annual utilization. Therefore, attention to groundwater for sustainable development is necessary (Velayati, 2009). In the last few decades a large number of people concentrated on groundwater research (Dawoud & Raouf, 2008; Subba Rao, 2006; Solomon & Quiel, 2006; Sander, 2006; Israil & et al. 2005). But published literature on sand stone and in particular Aghajari sand stone formation in Iran is limited. On the other hand Aghajari sandstone formation occupies a large part of the area and the only source of water is groundwater. Springs with variable discharge are rising from sandstone rock to meet inhabitants water needs. Though, the number of springs is prominent, but on account of low discharge people are in shortage of water. The main aim of this investigation was to find out the most favorable location with respect to groundwater potential in sandstones rocks of the area. Field data indicated that different parameters are controlling groundwater occurrence. Fracture and joint density, sandstone and marl thickness, soil cover and slope are significant influencing factors. In the present investigation, in order to determine promising groundwater zones each foregoing factors was taken into consideration as a GIS layer. Field evidences have been used to evaluate each GIS layer and to allocate their weight.

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Study area The study area which occupies 680 km2 is located in Khuzestan province in the southwest of Iran (Fig.1) and bounded between 31 ˚ to 32 ׳57 ˚ N and 48 ׳18 ˚ to 49 ׳56 ˚ E. The average ׳22annual temperature and rainfall for the last 35 years are respectively 25.17oC and 445 mm. The area experiences semi-arid climate with high temperature and evaporation in summer. Geology The exposed rock formations in the area include Gachsaran (Lower Miocene), Mishan (Middle Miocene), Aghajari (Upper Miocene), Lahbari member (Upper Miocene - Lower Pliocene) and Bakhtiari (Upper Pliocene). The youngest and oldest formations are respectively Bakhtiari and Gachsaran (Fig.1). The Aghajari formation which occupies most part of the area (350 km2) consists dominantly of sand stone and marl and sand stone incorporate prevailing constitute of Lahbari member. Structurally, the study area with NE-SE trend is counted as a part of Zagros structural folded belt. The main geological structure is Masjid-e- Soliman fold with NW-SE trending axis and in addition to this, tectonic processes have resulted development of joint and fracture systems and fault zones. Lineament In fact, every linear phenomenon is an indicator of surface fracture zone and in turn displaying importance of geologic origin and tectonic event. As linear pattern are index of crust fracturing, therefore, in areas where linear density is increased consistency of joints and fracture is also more. Based on this hypothesis, lineaments are taken into account as groundwater deciphering. Thus, in areas where fracture density is significant water infiltration and transportation into sand stone is being enhanced (khoobyari & et al., 2010). Accordingly, there is a good correlation between fracture zone and high groundwater potential zone in the study area and to keep distance from fracture zones results considerable reduction in permeability. The lineament map of study area is given in figure 2. Sand stone marl thickness ratio The present information indicates that occurrence and thickness of sand stone plays a significant role on groundwater occurrence while marl layer is a limiting factor. Therefore, the map showing ratio of sand stone thickness to marl thickness was prepared exhibiting high, moderate, moderate to low, low and very low water potential zones (Fig.3). Slope Slope is seriously affecting infiltration rate and steep slope is a constraint factor. In order to visualize slope impact on water occurrence a slope map was depicted in figure 4. Soil cover

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In some parts of the study area soil thickness is remarkable and in the same areas water availability is low. Thus, another governing factor influencing water bearing horizon is marl soil. The soil thickness map is given in figure 5. Spring The springs discharge is reflecting groundwater condition of an aquifer (Kresic & Stevanivic, 2010). In the study area spring discharge was taken into account as an index to determine aquifers potential. Therefore, based on discharge a boundary map for springs was prepared and areas locating in higher discharge zone exhibiting more promising aquifers. The springs discharge map of the study area is given in figure 6. Overlying and groundwater potential map Based on significant of raster layers in the area a weight was given to them and according to mathematical coincides in GIS, water potential map was prepared. According to this map five water potential zones including very high, high, moderate, low and very low was demarcated (Table 1 and figure 7). Conclusion The collected data in the present investigation has indicated that only a fraction of the study is promising with regard to groundwater occurrence. In the most part of the area (50%) aquifers are in moderate condition while 40% of the area suffers from shortage of water and aquifers are very poor. References

1- Velayati, S., 2009, Hydrogeology of Soft and Hard Formation, Theoretical and Practical principle, Mashhad’s Jahade Daneshgahi Pub. 396P, 7-8.

2- Dawoud, M. A., Raouf, A. R. A., 2008, Groundwater Exploration and Assessment in Rural Communities of Yobe State, Northern Nigeria, Water Resource Manage, Vol. 23, P. 581–601.

3- Subba Rao, N., 2006, Groundwater potential index in a crystalline terrain using remote sensing data, Environ Geol, Vol. 50, P. 1067–1076.

4- Solomon, S., Quiel, F., 2006, Groundwater study using remote sensing and geographic information systems (GIS) in the central highlands of Eritrea, Hydrogeology Journal, Vol. 14, P. 1029–1.

5- Sander, P., 2006, Lineaments in groundwater exploration: a review of applications and limitations, Hydrogeology Journal, Vol. 15, P. 71–74.

6- Israil, M., Al-hadithi, M., Singhal, D. C., 2005, Application of a resistivity survey and geographical information system (GIS) analysis for hydrogeological zoning of a piedmont area, Himalayan foothill region, India, Hydrogeology Journal, Vol. 14, P. 753–759.

7- Khoobyari, A., Kalantari, N., Charchi, A., Keshavarzi, M. R., Bagherzadeh, S,. 2010, Assessment of fractures role in occurrence of sand stone springs, (Case study: Masjed Soleyman and Lali), 13 th Symposium of the Geological Society of Iran, (in press).

8- Kresic, N., Stevanivic, Z., 2010, Groundwater Hydrology of Springs, Elsevier. 262 P.

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Table 1 Water potential zones and percentage area

Percentage Area (Km2) Conditions Zone1.85 8.5 Very high 1 12.7 58.5 High 2 47.2 217 Moderate 3 32.8 151 Low 4 5.45 25 Very low 5

Fig. 1 Location and geological map of the

Fig. 4 Slope map of the study area

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Fig. 2 Lineament density map of Fig. 3 Sand stone marl thickness

Fig. 5 Soil cover map of the area Fig. 6 Springs discharge map of

Fig. 7 Groundwater potential

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Designing Mollasadra Dam Right Abutment's Sealing System

Ali Ghanbari, Ali Reza Honarmand Nejad

1.Instructor of Geology Group, Tarbiat Mo'alem University

2.MSc in Geology, Basic Sciences College, Azad University, Sciences and Researches Branch

[email protected] [email protected]

Abstract Mollasadra dam is located on an alluvium of about 40m thick made up of alluvial sedimentations ranged from fine materials (incl. silt and marl) to coarse ones (coarse rubble particles, gravel, sand with clay paste). Practically, flow line passes through two layers causes high hydraulic gradients at the two layers' border. Due to the above, choosing most suitable sealing system considering execution, technical and economical terms and conditions is one of the main questions to be brought up. To ask this question, first of all using Seep/w software permeability data are analyzed. Then, every sealing method is modeled separately and the results are compared with total quantity of seepage from under dam foundation. Key Words: cut off wall, hydraulic gradients, sealing system, Seep/w software

1. Preface Issue of seeping through foundation and abutment of dams is of great importance in views of quantity of seeping and wastage of a considerable amount of reserved water behind dam, of technical problems resulted from seepage caused by hydraulic gradients and created interactional forces, as well as of the risks affecting stability of dam and erosion of the foundation. Thus, controlling this issue is one of necessities of each and every dam work. In this research, we try to introduce usual sealing methods of foundations and abutments of earth dams, present different tricks of seepage control and calculate quantity of seepage through Mollasadra dam foundation in each method with the use of Seep/w software. 2. General Geology of the Area Geologically, the area under study is located in zone of overthrusted Zagros or high Zagros. Overthrust of Zagros extends northwest– southeast in a direct line which defines a very deep and old joint and distinguishes boundary of Saudi Arabian and Iranian platform. [1] The most important element of Mollasadra dam's location is Kor anticline where the dam is located on its eastern chord. This anticline with a wavelength and trend of almost northwestern – southeastern is limited to a calcareous layer aged in upper Cretaceous (Sarvak formation). Of the main faults of the area is Zagros Fault. Zagros main fault is the largest fault in Iran and southeastern Asia.In this area there are two types of faults:transitional faults of Bakan and Ardakan,reverse faults of Sedeh and Sheshpir. Stratigraphy wise, the project extent ranges age wise (from old to recent) as follows: Sarvak formation (KL1, KL2 units), Goorpey formation, Neogen sedimentations (alternates between non-homogenous conglomerate with relatively poor cement and red and yellow

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marl) and current testament sedimentations (incl. alluvial terraces, flood plain sedimentations, alluvial cones and piedmont sedimentations). The KL1 and the KL2 units are mainly exposed in downstream and upstream of the dam's axis respectively. The most exposure of conglomerate unit is in the right abutment of the dam. 3. Engineering Geology: 3.1 Discontinuities system: To analyze status of joints in abutments and rock exposures at the flow weir and culvert extents and to study joint setting of each abutment 100 joints were surveyed and then diagram contour and discontinuities plates were set out on Schmitt grid. Rather than layered plates there are three types of main joints (J1 = 45/55, J2 = 170/80 and J3 = 250/73) at the right abutment. 3.2 Quality of Cores (RQD) RQD is percentage of sound cores of >100mm long to total cores. [4] Based on these results, average of the rocks' quality index in the left abutment and the foundation is about 70%. The average of the rocks' quality index is about 50% every where in the right abutment where constituted from marl, marl and bituminous limes and lime rock which are classified (Deere & Barton, 1963) as weak to medium rocks except in the weak conglomerate zones which have poor clay cement. 3.3 Permeability There are several factors contribute in permeability rate of cairns of which the most important ones are: discontinuities (joints, layering), cairn strength, tensile strength of discontinuous levels and strength of filling materials. Among them existence of discontinuities creates transmission routes around bore holes in which multiplicity of routes and their embranchments around boreholes is important. [5] In the right side of the dam location boreholes C1, DR1, DR2, DR3, DR4, and DR5 were drilled. Permeability status of the right abutment's cairn depends on its lithological conditions. In boreholes DR1-DR5 permeability test in conglomerate rocks was mainly done with Luphrane method. The permeability in the right side conglomerates measured 1.8 × 10-3 to 1.2 × 10-6. Boreholes T1, S1, DL1, DL3, DL4, and DL6 were done in the left side of Mollasadra dam. Permeability rate in boreholes DL1 and DL2 in the left side was great in -25 to -65m deep and larger than 100 Lugeon that demonstrates an impermeable zone. Studies on the drilled cores also show small and big solubility holes and vuggy joints. 3.4 Controlling behavior of water flow in the joints Out of 46 Lugeon tests, about 4% have laminar, 4% turbulent, 11% dilation, 16% washing out of joints and 65% impermeable behaviors. 4. Analyzing Seepage Status Using Seep/w Software To analyze the above, a geology cross section was prepared in parallel to the dam axis. Then, the boreholes and their relevant data were set out in the sections. Since 8 boreholes were done

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in the dam axis, the axis length was divided into 8 areas with different lengths accordingly. (Pic. 1) 5. Parameters Used in the Analysis To analyze the seepage relation of water flow in soil is bound to water level status and its changes as well as to the environment’s permeability conditions. [2] Based on the measurements, water level in downstream of the dam is 2050m from sea level. Normal water level in the upstream is 2115m from sea level. 17 boreholes were drilled in the extent of the dam. 8 of them were in the axis of the dam and data of which was used for seepage analysis in this paper.. Permeability values gained from Luphrane tests equal to Darcy permeability ratio with the unit of cm/s went directly under analysis. It is while the Lugeon test results which were in LU converted to Darcy permeability ratio using experimental charts and are used in the seepage analysis. [3] 6. Analysis Results 6.1 Seepage Analysis with No Sealing Water passing value from the location of Mollasadra dam without any sealing and only based on placement of the dam on the location was analyzed with the here below results (pic. 2) Q = 2.71 E – 1 m3/s/m Daily seepage rate equals: Q = 2.71 E – 1 m3/s/m × 86400 = 23427 m3/day 6.2 Seepage Analysis Using Sealing Methods Different sealing methods used are: • Grouting • Cut off wall • Grouting + cut off wall • Upstream impermeable clay blanket • Upstream impermeable clay blanket + grouting - Grouting There is no scheme in this stage for sealing of the alluvium and only grouting in to bed rocks with Lugeon 1, 3 and 5 was done. Seepage rate of flow described in 6.1 i.e. with no sealing method reduced from 23427 to 941m3/day by grouting down to depth of -65m and Lugeon 1. From this depth downward no sensible reduction in the rate of flow was seen. (Table 1) and (Pic. 3) - Cut off wall A cut off wall with permeability ratio of 1× 10-6 cm/s, 200m ling and 80cm thick was considered. Seepage rate of flow in the right abutment without using any sealing method reduced from 12031 to 287m3/day by construction of a 40m deep cut off wall. This reduction proves efficiency of this method.

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- Grouting + cut off wall In this method a cut off wall with different depths for sealing off in alluvial material and grouting into different depths and with a selected Lugeon (3 unit) for sealing off rock materials were used. Best results were achieved using grouting down to maximum 65m in calcareous rocks of the left side and constructing a cut off wall down to 40m in conglomerates of the right abutment. In this method, seepage rate of flow reduces from 23427 to 1547 m3/day. - Upstream impermeable clay blanket The upstream impermeable clay blanket thickness is 1m and coverage lengths are 0, 38m, 60m, 120m, and 150m. The aforesaid lengths are regardless of extending length of the dam’s crust in the upstream (152m). Permeability value of this impermeable clay blanket is also considered just like a clay core. - Upstream impermeable clay blanket + grouting In this method, an upstream impermeable clay blanket + grouting in to depths of 55m, 45m and 65m and Lugeon 3 were used. 7. Presenting the Optimum Sealing Method Yearly inlet volume of water into the dam reservoir is 415,000,000m3. Total capacity of the reservoir is 440,000,000 m3. Based on the calculation results of the seepage rate of flow in the last section, quantity of seepage from foundation and abutments of Mollasadra dam is 23427m3/day and 8551× 103 m3/year. Regarding the above results in the last section, in reduction of seepage rate: effect of grouting > the cut off wall > the upstream impermeable clay blanket. Proposed solutions for sealing of the dam are: - 1st solution: grouting down to -65m with Lugeon 3+ cut off wall of 200m long and 20m deep in the right abutment alluvium. - 2nd solution: grouting down to -65m with Lugeon 3+ upstream impermeable clay blanket of 60m long. - 3rd solution: grouting down to -65m with Lugeon 3 + cut off wall of 200m long and 40m deep in the right abutment alluvium + continuation of grouting under the wall to reach to suitable bed rock. The first solution has the least seepage rate, but due to the very high volume of required materials, difficulty construction of a 40m wall this method is not economical and therefore not proposed. Hydraulic gradient surrounding the wall in this method is 22 although the materials of the cut off wall are designed in way to be able to bear this gradient. However, erosion wise their safety is less than the other sealing methods. This solution is also not proposed due to unexpected seepage which occurs sometimes in poorly constructed areas – that is more probable in this solution due to extensive depth of the wall. In the second solution, an upstream impermeable clay blanket is used. Due to existence of alluvial terraces and extensive spread and thickness and specific grading (incl. clay and silt) of the in situ soil in the dam reservoir, a type of natural clay blanket is performed on the bed of

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the dam’s lake. Therefore, replacing the above said sedimentations with this materials is not only illogical but also non-economical. Finally, the third solution is proposed as the suitable option for easy construction of a 20m cut off wall and solidity of grouting until reaching suitable bed rocks in all sub layers of the dam location and also due to controlling of hydraulic gradients caused by construction of the cut off wall (by reduction of the wall length and continuation of grouting). 8. Final Results of the Research Due to the above, construction of a partial cut off wall down to approximate depth of 20m, continuation of grouting with Lugeon 3 under the wall until a suitable depth at the right abutment and grouting in rock materials of the middle part and the left abutment down to approximate depth of 65m is proposed as the optimum method of sealing. 9. References: 1. Darvish Zadeh, A., 1991. Geology of Iran, Nashre Danesh Emrouz publications. 2. Farough Hosseini, M., 2005. Rocks mechanics, Nashre Ketabe Daneshgahi Tehran

publications. 3. Nanvaylar, A., 1978. Grouting Engineering, Zayand Ab Consulting Engineers. 4. Vafaeian, M., 1998. Erath dams, Jahad Daneshgahi publications – Isfahan Industrial

Branch. 5. Lombardi, J., 2003. Grouting of rock masses, 3RD international Conference on grouting and

grout treatment.

Table1 – Changes in seepage rate of flow (m3/day) in lieu of changes in grouting depth with Lugeons 1, 3 and 5

Depth of grouting 0 12 25 36 45 55 65

Lu = 1 23427 14269 12469 12049 2956 1474 941

Lu = 3 23427 14490 12918 12394 4042 1499 1221

Lu = 5 23427 14684 13278 12740 4967 2450 1380

Picture 1- Hydrogeological section of dam axis

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Picture2 – Co-potential contour lines in Mollasadra dam’s body and foundation with no sealing

Picture 3- Chart showing changes in seepage rate of flow (m3/day) in lieu of changes in grouting depth with Lugeons 1, 3 and 5

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348


Reliability Analysis of Earth Dam: Case of Kalan Earth Dam – Malayer, Iran

Alireza Karamia,1, Mazaher Roozbahanib

a Department of Civil Engineering, Technical and Vocational School of Sama, Malayer branch, Iran

b Department of Civil Engineering, Technical and Vocational School of Sama, Malayer branch, Iran

Abstract Slope stability assessment is a geotechnical problem characterized by many sources of uncertainty. Beginning from a correct geotechnical characterization of the examined site, only a complete approach to uncertainty matter can lead to a significant result. Factors of safety (FS) provide a quantitative indication of slope stability which should be determined by experience and the degree of uncertainty that we think is involved in calculating FS. The reliability index of an earth dam in commonly taken as the value corresponding to the failure surface associated with minimum reliability index. However, embankment dams are considered as systems composed of several infinite number of possible failure surfaces associated with different reliability indices. In this paper, the reliability analysis has been performed on Kalan embankment dam of Malayer, Iran by a numerical procedure for locating the surface of minimum reliability index for the earth slope. Here, basic assumption, which considers soil properties of the embankment dam are statistically homogeneous, has been followed. Keywords: Earth Dam, Reliability Index, Factor of Safety, Slope Stability, Failure Probability 1. Introduction There have been numerous attempts in recent years to use a probabilistic approach complementary to the conventional approach for analyzing the safety of slopes. The conventional deterministic approach is based on minimizing the factor of safety (FS) over a range of candidate failure surfaces thereby determining the surface of minimum factor of safety, referred to as the critical deterministic surface. A common approach to determine the reliability of a slope is based on calculating the reliability index β corresponding to this surface. Probabilistic analyses have also been performed on arbitrary slip surfaces. Parametric studies have been conducted considering different specified surfaces not necessarily associated with the minimum factor of safety or minimum reliability index [1, 2]. Li and Lumb [3] located the critical deterministic surface and then used it as the initial trial surface to search for the surface of minimum β, referred to as the critical probabilistic surface. The geotechnical engineering designer has to provide a way to systematically incorporate uncertainty into the design process in a rational manner and to must take it into account the soil variability and optimize design [4-8].

1 Corresponding Author: E-mail: [email protected] , Tel: +98 918 851 2220

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Within the literature, there is a multitude reliability analyses can be used in routine geotechnical engineering practice. How should probabilistic methods be introduced to practicing geotechnical engineers who have no background in the probabilistic theory? These simple reliability analyses require a little effort more that involved in conventional geotechnical analyses [9]. As interest in probabilistic approach of slope stability analysis increases, there is growing need for algorithms to search for the minimum β surface. It is now recognized [10] that the search for the minimum β surface in the probabilistic approach is similar in principle to that for the minimum FS surface in the deterministic approach. 2. Reliability Analysis Reliability analysis plays a major role in considering the uncertainties influencing the design of earth structures. Any simple reliability analysis should include the following steps: Establishing limit states, identifying failure modes, formulating limit state functions, analyzing uncertainty, evaluating reliability and Assessment results [9]. The conventional factor of safety is defined as the ratio of limit capacity of soil to a demand in terms of loads:

SRF = (1)

in which R = capacity (resisting force or resisting moment); and S = demand (driving force or driving moment). Let fR(r) and fS(s) be the probability densities functions of variables R and S. The probabilistic measure of safety is the probability of failure, Pf in which should be smaller than certain reference values set a priori. The probability of failure is defined as (failure occurs if R<S):

)1( ≤=SRPPf (2)

Assuming statistical independence between the variable R and S the probability of failure can be expressed as:

∫ ∫+∞

∞

=

∞−

=-

)))()((sr

Rsf dsdrrfsfP (3)

The use of later formulation of probability of failure makes the simplification possible only for certain types of distribution of R and S such a normal distribution. In such case the notion of safety margin, MS=R-S, can be introduced [6]. It is Possible to derive the density function fMS(MS) of the random variable MS and the risk of failure is given as:

∫∞−

=0

)()( msdMSfP MSf (4)

In general, the calculus of the integrals in the preceding equations is particularly cumbersome. In this case, safety is defined by the reliability index, β, as [10]:

MS

MSEσ

β }{= (5)

in which E{MS} = expected value of MS; and σMS = standard deviation of MS, provides a simple quantitative basis for assessing risk i.e. probability of failure.

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3. Case Study 3.1. Description and Presentation of Kalan Dam Kalan earth dam (West of Iran) is selected as a case study to perform the reliability analysis. Its reservoir is a man made water body built on Marvil, 30 km south of Malayer, for farming and water supply purposes. The hydraulic characteristics of the dam are shown in Table 1. Kalan dam has a height of 47 m and crest width of 10 m. Maximum water height back of the upstream shoulder is 45 m. The outer slopes of the dam are made of 1V: 4H upstream shoulder and 1V: 3.5H the downstream shoulder respectively (Figure 1). 3.2. Properties of the Dam and Foundation Materials The compacted materials were evaluated according to their maximum dry unit weight (γdmax), optimum water content (wopt), specific gravity (γs), liquid limit (LL) and plasticity index (Ip). The construction material for embankment and foundation were: Material A- Filter zone: granular material, Material B- downstream shoulder zone: granular material and clay with medium plasticity and Material C- soil foundation and upstream shoulder zones: clay with medium plasticity. The main physical and shear strength parameters are reported in Table 2. 3.3. Performance and Analysis of Kalan Dam The stability analysis of Kalan embankment dam and its foundation is carried out using a deterministic approach. The limit equilibrium Slide ver.5 program is used. Different modes of failures are implemented in Slide ver.5 program which provides a choice of methods of analysis including the following: Bishop's method, Lowe-Karafiath's method, Spencer's method and Janbu's method. The former method has been selected to evaluate the safety factor. A minimum factor of safety (FS) of 1.46 for ellipsoid failure mechanism has been found. An example of Slide program analyses of Kalan dam is shown in figure 2. Subsequently, for the reliability analysis of Kalan dam, only the ellipsoid failure mechanism will be considered. 4. Reliability Analysis of Kalan Dam Recently, special attention has given to the role of spatial correlation. Some recent papers dealing with the concept include those by Mrabet and Giles [6]. Many studies stressed out the effect of existing auto-correlation on the results of probabilistic models of compacted earth slopes analysis. Similar pattern have been found for mechanical properties and the exponential auto-correlation function between two different points within the compacted soil of the Kalan dam has been retained. Due to the lack of data concerning the horizontal auto-correlation function, we were reported to Anderson’s work [11] to establish one. We therefore, obtained the following function:

)065.0exp(9 xxhor −=ρ (6) In this article at first groundwater analysis has been done by finite element method then the calculated probability associated to the critical failure surface constitutes a lower limit of the global probability of failure of Kalan dam. Subsequently, we calculate the global probability of failure in respect to the following condition: -Cross-section of Kalan dam as considered in the above analysis (figure 1).

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-Horizontal auto-correlation distance is: 60 m -Vertical auto-correlation distance is: 5 m -Coefficient of variation of the cohesion of the Kalan dam is: 1 The global failure probability is calculated using the following equation:

∏=

−−=n

ifiglobal PP

1

)1(1 (7)

Where Pfi is failure probability corresponding to the ellipsoid failure surface i. The global probability of failure is P = 0.015. This value is close to the value associated with the critical ellipsoid failure surface. This calculation shows that the concept of global probability is coherent; should be considered, later, as the global probability of the project. In reality, these results show that other sources of uncertainty that should be taken into account including, but not limited to: 1. Ignorance of mechanisms of failure; 2. Ignorance of the entire history of dam behavior and 3. Ignorance of the horizontal auto-correlation length. 5. Conclusions The present study has been oriented to provide and compare useful model application results to a slope stability reliability analysis. Although this model is greatly used and diffused, some aspects connected to their application should be further investigated. Such aspects (e.g. the search for the most critical probabilistic surface, βmin calculation, data uncertainty propagation and modelling) play an essential role for a good quality solution. However, the reliability analysis should be considered as an efficient tool that complemented a conventional deterministic analysis such as the equilibrium limit analysis. Also The global probability of failure value is close to the value associated with the critical ellipsoid failure surface. Particularly, correlations between different properties that characterize compacted materials and their corresponding horizontal auto-correlation lengths generate main uncertainties in the probabilistic model. The application of a simple algorithm with a correct experienced-based parameter definition provides results that are in good agreement, mentioned slope stability solutions, in terms of reliability index and probability of failure. This seems to encourage the application of similar uncertainty treatment to the slope stability assessment. Acknowledgement The authors would like to thank Technical and Vocational School of Sama, Malayer branch for providing facilities and equipments to perform this project. The paper has been financial supported by the Technical and Vocational School of Sama, Malayer branch, the special fund for major state basic research project. Refrences 1. Bergado, D. T., Anderson, L. R., 1985, Stochastic analysis of pore pressure uncertainty for

the probabilistic assessment of the safety of earth slopes: Soils and foundations, v. 25(02), p. 87–105.

2. Chowdhury, R. N., Xu, D. W., 1993, Rational polynomial technique in slope reliability analysis: Journal of geotechnical engineering division ASCE, v. 119(12), p. 1910–28.

352


3. Li, K. S., Lumb, P., 1987, Probabilistic design of slopes: Canadian geotechnical journal, v. 24(04), p. 520–35.

4. Cherubini, C., 1997, Data and consideration on the variability of geotechnical properties of soils: Proceedings of the Conference on advances in Safety and Reliability, ESREL, p. 1583-1591.

5. Mrabet, Z., 1999, Reliability analysis of homogeneous earth fills: A new approach. Proceeding of the eight International Conference on Applications of Statistics and Probability in Civil Engineering, ICASP8, Australia, p. 499 – 507.

6. Mrabet, Z., Giles, D., 2002, Probabilistic risk assessment: a key tool for reducing uncertainty in geotechnical engineering: Invited paper, 3rd International Conference on Computer Simulation In Risk Analysis and Hazard Mitigation, Portugal, p. 3-14.

7. Mrabet, Z., 2004, Some aspect on reliability in geotechnical engineering: 4th International Conference on Computer Simulation In Risk Analysis and Hazard Mitigation, Invited paper, Greece, p. 75-84.

8. Mrabet, Z., Ridha, M., Kheder, Kh., 2006, Reliability Analysis of Earth Dams: case of EL Houareb Dam – Kairouan – Tunisia: 3rd International ASRANet Colloquium, United Kingdom.

9. Li, K. S., Cheung, R. W. M., 2001, Discussion search algorithm for minimum reliability index of earth slopes by Hassan Am.Wolff TF: Journal of geotechnical and geoenvironmental engineering, v. 127(02), p. 197–8.

10. Benjamin, J., Cornell, C. A., 1970, Probability, Statistics and Decision for Civil Engineers: McGraw-Hill, New York.

11. Anderson, T. W., Hsiao, C., 1981, Estimation of dynamic models with error components: Journal of the American Statistical Association, v. 76, p. 598-606.

Table 1. Hydraulic characteristics of Kalan dam

Area of basin pouring 384 km2 Total capacity 45 × 106 m3

Yearly average contribution 35 × 106 m3

Table 2. Physical properties and shear strength parameters

Materials Properties

A B C

WL (%) - 25 39 IP (%) - 15 22 W (%) - 13 14.5 γd/γw - 1.5 1.83

φ (degree) 35 22 26 c (kPa) 0 8.5 11 c = cohesive strength, φ = friction

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Figure 1. General cross section schematic of Kalan dam.

Figure 2. Analysis of downstream slope of Kalan dam using limit equilibrium to find the ellipsoid failure surface (Janbo’s simplified method, Slide 5)

Janbu’s method (Critical surface)

Maximum water level

354


Matrix Method for Transformation between different arrays by Using Exponential

Approximation of Kernel function

Heiat,A and Dr Meshinchi ASL,M

Science and Research Branch, Islamic Azad University, Tehran, Iran

Abstract In this research at first we present Matrix method to synthetic investigation which is based on exponential approximation of kernel function. Then this method is used for transformation sounding data of one electrode configuration to that of another configuration .at last the efficiency of matrix method is shown by some synthetic and practical examples. All of the stages in this research are done by a Matlab program. Matrix Method Stefanesco in 1930 obtained the expression for the potential at an arbitrary point placed at a distance r on the surface of N _ layered earth model, due to a point electrode of current strength I. The layers are characterized by the resistivities Nρρρ ,....,

21 and thicknesses

121 ,....., −Nddd . The equation for potential V(r) as a function for r can be written as

( ) ( ) }21{2

)}(21{2

)(: 011 λλρλλλρ drkJ

rIdrJkIrV ∫

+∞

+∏

=+∏

=o

o (1)

Where )(0 rJ λ : is the Bessel function of the first kind with order zero.

)(λk : is the stefanesco Kernel function, solely determined by thicknesses and resistivities of the layers. λ : is a integration variable ranging from 0 to ∞with dimension 1−L For determining stefanesco kernel function we use Pekeris recurrence relation which is:

111

1 ,;)tanh()tanh(

−++

+ −==++

= iiii

ii

ii

iii hhtP

tikPtiPKK

ρρ

λλ (2)

h is depth and t is the thickness of the layer. K in equation 2 is slitcher kernel function. The relation between stefanesco kernel function and slitcher kernel function is:

)(21)( λλ kK += (3) In this stage we use exponential approximation of kernel function which is:

∑=

−=ρ

λελ1

)(i

ifiek (4)

iε Is Position of approximation and if is coefficient of approximation. By using equation 4 and lipschitz integral equation 1 changed into this equation

355


(5) (6)

Apparent resistivity for a system with two current electrodes 21 ,AA and measurements electrodes M , N is:

IVV

rrrrnm

a−

+−−= −1

4321

}1111{2πρ (7)

Where measurements of 4321 ,,, rrrr are determined according to picture 1

Figure 1

By using various type of electrode arrays with attention to equations 7,6,5 for symmetrical arrays we have:

( ) ( ) ( ) ( ) ( ) ( )

( ) ( )

2 1 1

21

1

1,1 1

{1 , }(9)

i i i

p

a ii i

mG r mr G r G mrm m

f G r mrρ ρ=

= −− −

= +∑ (8)

value of m is 1.1 for schelumberger array, 2 for Wenner array, and ∞ for pole pole array. For various type of dipole dipole equation of apparent resistivity is;

( )

( ) ( )( )[ ] ( )

)11(]/1

31[/1

/2

)01(}1{

22/32

31

1

ii

iDie

p

iDiei

Dae

rP

r

rrG

rGf

∈+−

∈+

∈=

+= ∑=

ρρ

P in equation 11 is o.5 for radial dipole, 0.33 for perpendicular dipole, 1)(cos3

)(cos2

2

−θθ For

parallel dipole and 0 for azimuthal dipole array. If we have q measurements for r and p measurements for ε so we definite matrix pqE .][ and

1.][ qk and pqG .][ according to these equations:

. ijeE jiλε−=, ( 12) , )( ii kk λ= (13) , ),(, jiji rGG λ= (14)

kEF 1−= ( 15) , tt EEEE 11 )( −− = (16) tE is transposed matrix of matrix E.

With the equations 12,13,14 we changed 9 and 10 into matrix form .According to equation 5 and 9 apparent resistivity is determined with general equation which is )1(1 GFa += ρρ so Variable x is determined with this definition:

1

1

ρρρ −

= ax (17).

According to equations 9 and 10 in matrix form the formula for x is;

( ) ( )

( )( )( ) 2

122

1

1

1

2

}1{2

ri

rrG

rGfr

IrV

i

i

p

ii

+=

+= ∑=

ε

πρ

356


GFx = (18) Now we can compute apparent resistivities over an arbitrary layered earth. If we have apparent resistivities for two various electrode arrays on the same model , we will be able to compute measurements of one electrode array based on the other one.

FGx 11 = (19) FGx 22 = (20)

So it is clear that 11

1122 )( xGGGGx tt −= (21) Now we can compute 2x by 1x . Now let see some examples to find the efficiency of the Method to compute apparent resistivities over some synthetic models. Example 1: this is a three layer earth with 20;5;10=ρ and d=5; 10 The results of Example 1 are shown in figure 2. Example2: this is a three layer earth with 20;50;100=ρ and d=2; 10 The results of example 2 are shown in figure 3. Example 3: this is a four layer earth with 10;100;50;200=ρ and d=1; 10; 20 The results of this example are shown in figure 4. Now we consider a practical example. This example includes one profile with 3 soundages that are A1 and A2 and A3 in Soltanieh which is a city in Zanjan state in Iran. Data have been acquiesced by schelumberger configuration. And we have computed the results for Wenner and dipole dipole array by using field observations. The results are shown regularly in figures 5 and 6 and 7.in this figures we can see field curve and transformed Wenner and dipole dipole curves. And then by inversing data for each configuration we reached the resistivity section for configuration which is shown regularly in figures 8 and 9 and 10. By comparing sections with each other it is clear that in Wenner section has the most vertical resolution .on the other hand in dipole dipole section surface layers are more clear than other sections. So by combining the results of field observation and transformed data we will have more accurate interpretation.

100

101

102

103

100

r

prop

ortio

nal a

ppar

ent

resi

stiv

ity

10

010

110

210

3

10-0.2

10-0.1

100

100.1

100.2

r

prop

ortio

nal a

ppar

ent

resi

stiv

ity

Figure1 :apparent resistivity curves for example 1 Figure2:apparent resistivity curve for example 2

Sch Wenner d.dipole

Sch Wenner d.dipole

357


100

101

102

103

10-2

10-1

100

101

r

prop

ortio

nal a

ppar

ent

resi

stiv

ity

100

101

102

103

10-0.5

10-0.4

10-0.3

10-0.2

10-0.1

100

100.1

r

prop

ortio

nal a

ppar

ent re

sist

ivity

Figure 3 :apparent resistivity curves for example 3 figure4:field schelumberger data and transformed data data in Wenner and d.dipole for A1

100

101

102

103

10-0.4

10-0.3

10-0.2

10-0.1

100

100.1

r

prop

ortio

nal a

ppar

ent

resi

stiv

ity

10

010

110

210

3

100

r

prop

ortio

nal a

ppar

ent

resi

stiv

ity

Figure5: field schelumberger data and transformed Figure 6;field schelumberger data and Data in Wenner and d.dipole for A2 transformed data in Wenner and d.dipole for A3

Figure7:Resistivity section for field schelumberger data

Figure8: Resistivity section for transformed data in Wenner configuration

Sch Wenner d.dipole

Sch Wenner

d.dipole

Sch Wenner

d.dipole

Sch Wenner

d.dipole

358


Figure 9: Resistivity section for transformed data in dipole dipole configuration Conclusion: According to the results Matrix method is an accurate method for synthetic modeling and also it can be a good method for the transformation resistivity sounding data of one electrode configuration to that of another configuration. transformed data satisfied field observation and in addition they have some special advantages which are related to the second configuration. Reference:

1_Koefoed,o.,1979.Gosounding principles,1,resistivity sounding measurements. Elsevier science publishing co.

2_Niwas,sri and Israil,M.,1986.computation of apparent resistivity using exponential approximation of kernel function.Geophysics.,51,594-1602

3_Niwas,sri and Israil,M.,1989.Matrix method for the transformation of the resistivity sounding data of one electrode configuration to that of another configuration. Geophysical prospecting. vol . 37,290-221

4-Niwas,sri and Israil ,M and khatri,KN.,1991.Efficiency of the Matrix method in resistivity data interpretation ,seminar on deep exploration, IIT, Khargaptur, India.

5_Niwas, sri.1994.Quantitative interpretation of dipole resistivity sounding data using matrix method., Proc. Environmental aspects of ground water development.11-74.

359


Seismic Vulnerability of Historic Hydraulic Structures of Shushtar City, southwestern Iran

Arash Barjasteh,

Khuzestan Water & Power Authority (KWPA),

Dam and Power plant Development,

Golestan Road, P.O.Box 61335-137 (e-mail: [email protected])

ABSTRACT This article assesses the seismic vulnerability of historic hydraulic structures in Shushtar city in Khuzestan Province, southwest of Iran. The city has a few numbers of these structures being called as Shushtar hydraulic ring which were constructed over Karun River and should be repaired and rehabilitated. The so called ring is consisted of 8 dams, weirs, bridges and about 38 water mills, all of them were erected during the Sasanid Imperial period about 1700 years ago. The quality of construction material and workmanship are almost well. The bridges, dams and weirs are heavy, single or multi-span arch construction. The bridges and water mills are primarily of brick masonry construction, but in the dams and weirs some notable stones and mud-bricks also a highly cementacious mortar called Sarooj have been often used. The structures are founded on Agha Jari Formation of light yellow sandstones with marlstone inter-layers. A review of the available historical and recent sources on the earthquake events indicate that as part of the Zagros active fold belt, the area had some weak to moderate earthquakes although, the instrumental records are rare. According to the seismicity maps of the region and previous researches, a range of 4.5–5 magnitude earthquakes (Ms scale) with 0–20 km focal depths have been estimated. Besides, the area has a high risk potential based on the national seismic codes. The hydraulic structures show some damages not necessarily due to earthquake events but partly due to rural development. A classification of the structures could be made according to their seismic vulnerability. Regarding to the earthquake intensities and the location of the structures, damage and survival intensity levels are to be calculated for these structures which could prove that immediate rehabilitation and repairing operation of the mentioned structures are necessary. Key words: Seismicity, Historic hydraulic structures, Shushtar, 1. Introduction Earthquake events have had a long history of destruction in the Iranian plateau. Their records date back to the 4th and 3rd millenniums BC. In this regard, vulnerability of historical monuments especially hydraulic ones as treasures of nations has been focused by researchers in recent years, in need of protection from the future earthquakes. In the present article, the seismic vulnerability of historic hydraulic structures in Shushtar city (Fig. 1.) in Khuzestan Province of south western Iran regarding their tectonic environment and site geology is investigated. The study is based on a review of previous researches and recently geotechnical investigations. The study concentrates on the geological structure and regional tectonics besides geotechnical properties of the mentioned structures. These structures varying in size

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and form have common site geology features, which makes a comparative study possible. They are all masonry structures made with fired brick, mud brick or stone masonry with lime, gypsum or 'sarooj' mortars. The studied hydraulic structures include bridges, dams, wiers, tunnels, and water mills. These structures were built with better material and workmanship compared with the ordinary buildings. Retrofitting of these structures is cruicial in view point of geotechnical earthquake engineering as well as geoarchaeology and geotourism. 2-Geological setting and stratigraphy The Zagros Fold-Thrust Belt being located to the northeast of the Persian Gulf is a branch of the Alpine-Himalayan Orogenic belt divided into three major structural zones [1] namely: the Sanandaj-Sirjan Metamorphic Belt (zone 1) , the high Zagros(zone 2) and the Simply Folded Belt (zone3). Most part of Khuzestan Province is located in zone 3, being comprised of parallel, long anticlines and synclines. The Formations on which the structures were built, are Agh Jari Sandstones of Mio-Pliocene and Bakhtiari Conglomerates of Pleistocene [2,3,4]. Both of them are gently dipping in the area and follow the general trend of the Zagros Fold-Belt i.e., NW-SE. The former is mainly composed of sandstones and marlstones and the latter is consisted of poorly rounded mainly calcareous conglomerates. The average attitude of joint systems in the area is N40-60W and N40-60E with nearly vertical dip. From a seismotectonic point of view, the area is located in the Zagros active fold belt with some weak to moderate background seismicity. Accordingly, a range of 4.5–5 magnitude earthquakes (Ms scale) with 0–20 km focal depths have been estimated. A comprehensive account of the relevant historical sources is given by Ambraseys and Melville [5,6]. They used 262 Iranian earthquakes of the 20th century for which values of magnitude (M), the radius of perceptibility (r'), re-defined as the mean epicentral distance at which the shock was felt with an intensity IV (MM) and the macroseismic intensity (Io), measured on the Modified Mercali scale, to derive at the following relation; M = -0.74 + 1.98 log(r') + 0.28(Io) (1) The surrounding region suffered weak to moderate shocks in time according to the previous studies [6]. 3. Historical sites and construction materials Due to of favorable condition of life besides good climate, water abstraction by different structures became popular around Karun River in Shushtar city. Shushtar Hydraulic System can be traced back to 5th century B.C. Some of the hydraulic structures are belong to Hakhamaneshian (Hakemanids), e.g., Daryoon Canal and some of them are related to Sasanid (Sasanian) Period, e.g., Gargar Wier [3,4]. There are 12 main hydraulic structures which can be classified as a) bridges and dams b) wiers and c) water mills. Of them the most important and famous are: Band-e Mizan, Gargar wier, Shadervan bridge, Daryoon canal, Lashgar bridge, and Band-e Khak (Fig. 2,3,4). Some of these structures were destroyed by floods and wars but some are still working or repaired to work. A review of the general features of the structures can be found in relevant papers. The majority of monumental buildings in Iran were built with fired bricks. Some large stone masonry and mud-brick structures have also survived

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to the present day. Fired brick is an Iranian invention dating back to the early 2nd millennium BC. In construction of different buildings in different periods, a verity of mortars has been used. The foundations were made of 'Shefteh', a lime mortar-stone masonry construction. In construction of the studied structures a highly cementacious mortar called Sarooj was often used. Sarooj is a mixture of lime (35%), sand (40%), ash (20%) and clay (5%). Sometimes by adding a quantity of goat's hair, the mortar was reinforced. Generally, extensive erosion and corrosion happened at the location of clayey lenses within the sandstones layers of Agha Jari Formation. In addition, some collapse and damage occurred in the tunnel roofs mainly along the existing joint sets. The intrusion of waste water from sewerage system into the tunnels also caused failures and corrosion in the roofs and walls. Part of the collapses is due to heavy vehicle traffic load e.g., over Gargar weir which acts as a bridge to facilitate urban transportation. As the RQD values of the surveyed layers were too low [7] it is suggested that some failures might happen that could be intensified during earthquake events. 4-Conclusion Due to tectonic activity of the study area, weathering of the foundation formations, geotechnical weakness of the geological layers and unfavorable urban development, most of the structures are sensitive to earthquake events. According to the research, al of the structures are vulnerable regarding seismotectonic, geotechnical and structural properties. Previous studies also indicated that the hydraulic structures are solid elements with short period frequency. It is proposed that suitable seismotectonic modeling, geotechnical investigations and structural studies be carried out to properly protect the structures from much extensive destruction. Besides, a classification of the structures could be made according to their seismic vulnerability. Regarding to the earthquake intensities and the location of the structures, damage and survival intensity levels are to be calculated for these structures which could prove that immediate rehabilitation and repairing operation of the mentioned structures are necessary. 5-Acknowledgement The authors wish to especially thank Khuzestan Water & Power Authority (KWPA), Water Engineering Standards and Research Bureau of Dam and Power plant Development for financial support. We should express our thanks to Mrs. R. Ghilav for reviewing the manuscript. 6-References

1-Falcon, N. L. Southern Iran – Zagros Mountains, in Spencer, A. M., editor, Mesozoic Cenozoic orogenic belts: London, Geological Society Special Publication 4, p.199– 211, 1974.

2-Barjasteh, A. Structural analysis of Kohnak Anticline in Dezful Embayment (in Persian), Proc. 4th Symp. Geol.Soc.Iran, Tabriz University, Tabriz, pp.365-367, 2000.

3-Barjasteh, A. Geotechnical investigations for the rehabilitation of historic hydraulic structures around Shushtar City, Iran. Proc., Int. Conf. Construction of historical cities and geotechnical engineering. Saint Petersburg, Russia, 2003b.

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4-Barjasteh, A. Investigation of geological and geotechnical properties of historic Daryoon tunnel and intake of Shushtar City, Iran (in Persian).Proc. 3rd NIAEG, Bu-Ali Sina University, Hamedan, Iran. 2-4 Sept. 6p, 2003..

5-Mahdavi Adeli, M, et al.,. Seismic hazard analysis around Shushtar City and determination of

uniform hazard spectrum (in Persian) Proc., 4th National Conf. on Seismic Resistant Design of

Buildings, Standard No. 2800. BHRC, Tehran, Iran. 10 p, 2009.

6-Ambraseys, N. N. & Melville, C. P. A history of Persian earthquakes. Cambridge University Press, 1982.

7-SES Consulting Engineers Co. Geotechnical report of Daryun tunnel, 77pp. 2000.

Figure1. Location of the study area

(green square) relative to the main seismotectonic elements of Iran

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Figure2. Northward view of Band-e Mizan , north of Shushtar .

Figure3. Figure2. A view of Pol-e Lashgar (Troop bridge) in south of the city.

Figure4. Helicopter photo of Band-e Gargar and watermills in the east of the city.

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New Method for Landslide Stabilization

Ataollah DadashpourEmail: [email protected]

Prof. Robert Minasyan Email: [email protected]

Seyyed Ali Hamidi Email: [email protected]

Mahmoud Shirchi Email: [email protected]

Eshrat Ahmadi Khatir Email: [email protected]

Abstract Landslide of North Alborz land slope is one of the geological phenomena, that its occurrence is affected by various natural and unnatural factors. Statistical studies of more than 520 Landslides occurred in Mazandaran Province states that one of the most basic and effective factors in landslide is the existence of water in the land where layers are susceptible to slide. Removing water from land slope can increase shear resistance of soil and to some extent stabilize it and fix the landslide. Therefore, identifying the exact path of underground water flow of risky upstream areas of slope land, and stopping water from entering to the landslide place, can present a useful solution to stabilizing landslides and preventing the continuous mass movement process. wherefore the underground water flow usually enter the sliding mass through the fractures and faults in the upstream landslide place, and reduce soil shear strength and thus create a surface and sliding mass down the slope lands . In this new method of landslide stabilization, by using the Electromagnetic Method (also Geoelectric Method can be used), underground water flow path in upstream areas of the sliding mass can be identified, and the exact depth of lush layers can be specified and then drilling the wells and water pumping automatically can be done, before the mass slid. By stopping water from entering the slope lands susceptible to slide and sliding mass, the depth of water table in sliding mass place loss and therefore the soil shear resistance increase. Finally the landslide can be stabilized to some extent. It is necessary to dig some observation well in the slope lands susceptible to slide in order to have the statistic of water table depth level range. In this study for three villages in Mazandaran Province (Estakhr-posht in Neka – Chouret in Sari – Shahroud-kola in Qaemshahr) that have suffered from landslide, the stabilization operations with this new method was implemented that have had good results. For example, in Shahroud-kola a 30 meter depth well was dug in upstream sliding mass and in the line of Underground water flow. After pumping the water automatically for some day, the amount of 5350 liters per day were drained, that causes loss of water table in sliding mass.

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Key words: 1 – Electromagnetic2 – Landslide 3 – Arashk4 – Hydrogeology 5– Stabilization 6 – Control Well Introduction Landslide is one of the geological phenomena in the North Alborz slope lands. According to the definition, Landslide is movement of a part of slope materials along the specific surface of rupture. Although various factors such as underground water, slope, soil type, vegetation, tectonic, thickness of soil, the direction of slope layers, Azimuth, rainfall amount and human activities on land are involved in the slope landslide incidence, but The role of water in a Landslide incidence is considerable as a major factor. Usually the most important direct reason that unbalances the shear stress and shear strength of soil is underground water. By increasing the water content in the mass, soil shear resistance will be decrease. And by increasing the moisture of soil's weight per unit mass, the share stress will increase [FAO]. If the underground water could be controlled in a suitable way in susceptible zone of landslide or slipped slide area, to some extent, proportional stabilization of the zone will be achieved. Subject definition Landslide occurrence in different areas such as villages, roads, agricultural lands, forest regions ... especially in residential areas will cause lots of damage, harm and loss. From field surveying of landslide which occurred continuously in different parts of Mazandaran province during fifteen years (I have visited more than 200 cases and studied them), and also from reviewing statistical information about more than 520 registered Landslide of different parts of Mazandaran province in the form Landslide Database of Iran (landslides review group(2000), Ministry of Agriculture), all indicate that the most fundamental factor is water, and for some of them the damages and the costs of executive consolidation has been remarkable. As a practical example, stabilizing one zone in Sari - Kyasr road in Mazandaran province by piling method that costs more than 10 million dollar, can be mentioned. By the way, if the exorbitant costs of landslide stabilization could be reduced by using one of the new appropriate methods alone or as a complementary solution, it will lead to saving national resources and some good results will be obtained. Research objectives 1) Reducing executive costs of stabilizing landslide to down to approximately 0.1 percent of usual methods. 2) Prevention of landslides in susceptible zone. 3) Prevention of morphological changes and land damages, for early stage moving landslides. 4) Optimal use of underground water extraction for agricultural purposes and in some cases even for drinking.

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Research method Methodology is based on electromagnetic and the most important success factor of this method is Identify the exact underground water resource of upstream areas. Common methods such as Geo-Electric, seismic and other methods are very expensive and time consuming, but in this method an electromagnetic devices (Arashk) – invented by Seyed Ali Hamidi – is used. The device detection method is based on absorption of invisible infrared waves. Underground water flow usually enter the slip mass through fractures and faults that are in the upstream of slip location and reduce soil shear strength and thus create slip surface and cause slip mass movement down to the slope . In this method, the underground water flow path in the upstream of slip mass will be identified, and then the number and the exact depth of lush layers are determined. The next step is to determine the exact drilling pumping wells point and drilling depth. Drilling specified wells and continuously pumping underground water, result drop in water table in slip mass and thus the shear strength of soil of the slope will increase and at the end landslide will be stabilized. It should be mentioned that in order to record the statistics of water table Changes it is required to drill a control well in slip mass and in slope zone that are susceptible to slip. Research results This new method was applied in three villages in Mazandaran Province (Estakhr-posht in Neka city, Churetin Sari city, Shahrud-kola in Qaemshahr city) that have suffered from slippage, and then the executive operation of the landslide stabilizations result to success. Here are the statistics of Shahrud-kola as an example: Landslide of Shahrud-kola cause damage to five residential units, one old public bathroom, 195 m of the village entrance asphalted road and some orange gardens. Sliding mass dimensions were 500 meters length and 195 meters width and the settlement at the cross point with road were about 1.5 m. First, by using Arashk the transversal profile of slip mass along the road was considered to define the underground water flow. Thus three path of underground water flow that were feeding sliding masses were identified, which their specification are as follows: Point A: The coordinates: (4031462 - 666263) UTM Underground water flow path direction (N 80 E) and total length of the water table is 750 meters which 300 meters is located in upstream and 450 meters is located in downstream. Four hydrous layers were identified in this direction: the first layer with a depth of 10 meters, the second layer with a depth of 16.5 meters, the third layer with a depth of 22.5 meters and the forth layer with a depth of 37.5 meters. * We ignore to mention the number and depth of soil layers for all of points here. The width of underground water flow path has been recorded as 6 m using Arashk. Point B: The coordinates: (4031540 - 666240) UTM Underground water flow path direction (N 85 E) and total length of the water table is 780 meters which 450 meters is located in upstream and 330 meters is located in downstream. The number and depth of hydrous layers are recorded as Point A.

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The width of underground water flow path has been recorded as 7 m using Arashk. Point C: The coordinates: (4031567 - 666234) UTM Underground water flow path direction (N 75 E) and total length of the water table is 850 meters which 400 meters is located in upstream and 450 meters is located in downstream. Three hydrous layers were identified in this direction: the first layer with a depth of 12 meters, the second layer with a depth of 18 meters, the third layer with a depth of 30 meters. The width of underground water flow path has been recorded as 5.5 m using Arashk. The elevation of all points is 100 m. Then, in order to identify the main current path of underground water which supplies the sliding mass, we survey upstream slip mass precisely using Arashk that lead to identification of mainstream underground water flow in direction (N 10 W) and a height of 160 meters above sea level. The specifications are as follows: Point K: The coordinates: (4031432 - 666419) UTM Total length of the water table is 2100 meters which 1400 meters is located in upstream and 700 meters is located in downstream. Three hydrous layers were identified in this direction: the first layer with a depth of 12.1 meters, the second layer with a depth of 19.1 meters, the third layer with a depth of 25.1 meters. The width of underground water flow path has been recorded as 8.5 m using Arashk. After drawing all points and directions of underground water flow on the map, it was specified that all three directions of A, B and C cross point K direction. It means that the mainstream underground water flow of point K direction were feeding three directions of A, B and C. So in order to stop underground water flow of A, B and C we suggested to drill a 30 meters deep well at point K. The job was done and pumping results is given in the table (1). The recorded statistical data indicate that: 1) 5350 liters of water per 24 hours has been pumping. 2) Recording water table level of control well on sliding mass indicates a loss of 20 cm after 24 hours of pumping. 3) After 7 days of pumping we could stop entering of about 37450 liters of water to sliding mass. This lead to a loss of 140 cm in water table level in sliding mass. Conclusion The result of this study will answer to many questions such as: Is it impossible to use new method like ours to stabilize some landslides with a lower cost? Whether it is better to use drainage method or prevent entering of water to a sliding mass, yet many of experts are discussing about it. And there is another question: Can we increase the depth of drainage down to slip surface? Certainly it is impossible for landslides with slip surface depth of grater than 3 or 4 meters; but in our new method the depth of the slip surface isn't important. The other problem in drainage method for stabilizing a sliding mass is the type and density of drainage net, because the tissues of clay have poorly drained feature.

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The other question is if it is sufficient to construct only a retaining wall at the toe of slip mass and ignore the path of underground water? As a practical example, there was a sliding mass in Mohammad Abaad – Pole Sefid road (Savadkoh-Mazandaran Province). To stabilize the landslide, they construct a retaining wall for several times and each time it was destroyed, and finally they have spend a lot of money to remove most of the sliding mass and they have spend much more money to construct a costly retaining wall and it was temporarily stabilized. Isn't this research a better solution? Or at least, isn't it a appropriate complementary solution? Loss of water table in slip mass is directly related to increasing soil shear strength and increasing soil shear strength is directly related to stability of slip mass and so in this method, only by omitting a single factor (water) and without any other executive operations, we will be able to prevent the sliding mass movement. Suggestions According to the information and discussions presented in this article, in order to reduce the cost of stabilizing landslides and also to prevent repetition costs, the followings are recommended: 1) Identifying the on-ground and underground water supplies and upstream and downstream springs of slip mass accurately. 2) Controlling on-ground and underground water and leading them properly to an area out of landslide zone. 3) A professional experienced geologist in the filed of underground water resources and the ways of Landslide Stabilization should manage the planning type and style of stabilization. 4) Electromagnetic method can be used to know underground water resources better, because the precision is higher and the error is less than the other methods.

Table (1): Pumping results data water table depth of

control well after pumping (m)

water table depth of control well before

pumping (m)

The amount of water dischared (L)

parameter Date

- 2.30 - 22-04-2009 2.50 2.30 5350 23-04-2009 2.70 2.50 5350 24-04-2009 2.90 2.70 5350 25-04-2009 3.10 2.90 5350 26-04-2009 3.30 3.10 5350 27-04-2009 3.50 3.30 5350 28-04-2009 3.70 3.50 5350 29-04-2009

Thanks Special thanks to Mr. Pour-Mohammad, prior manager of Disaster Management Office of

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Mazandaran province and also special thanks to managers and engineers of Housing Foundation Office of Mazandaran province.

Sources

1 – Landslides review group, Iran landslide database, Ministry of Agriculture, (2000)

2 – Syarpour. M. "Landslide risk zone Map of south Khalkhal, Ardebil province" MSc thesis, Engineering Faculty of Tehran University, (1999).

3 – Ha'eri.M. & Samiee. A. "The new method of slope areas zonation for slippage hazard relying on Mazandaran province slippage zonation studies" Iranian journal of Earth Science, Geological Survey Organization of Iran, sixth year, Number 23, 1997.

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On Formation of Underground Water in Karst Region of "Neka R." (Province of Mazandaran, Iran).

Ataollah Dadashpour Email: [email protected]

Prof. Robert Minasyan Email: [email protected]

Abstract The under study “Neka R.” is an example of karst region where underground water is mainly formed at the expense of infiltration, influent and condensation processes. These processes are first of all promoted by physical and geographical conditions of the region. Infiltration feeding takes place from the surfaces of development of karst formations. In summer time this takes place predominantly after intense precipitation exceeding 10mm/day. Precipitation with fewer amounts almost completely is intercepted by trees and vegetation and evaporates. In wintertime infiltration feeding takes place mainly at the expense of melting of the lower part of snow cover and during rains. The size of infiltration feeding of the given area can be determined as the amount of effective precipitation, i.e. as the difference of average amount of precipitation and evaporation. We have carried out such calculations by higher zones of the region under study (for example with the rated altitude every 200m) based upon the values of average precipitation (mm), average evaporation (mm) and surface (km2) of the given region. Influent feeding in the given area takes place at the expense of surface flow absorption, formed in the area of karst development and non-karstic rocks. Flow absorption takes place in erosion and hydrographic network of the territory. In low water amount of influent waters is not big - generally flows of permanent streams of karst massifs do not exceed 5-6 l⁄s. In high water they sharply increase, reaching several tens of cubic meters per second. During spring snow melt maximum flows of influent streams are lower; instead the flow is more stable. The value of feeding of karst underground water with influent water fluctuates sharply during different seasons, which is determined by climatic conditions, as well as karst-hydrogeological features of the region. In a relatively warm period a significant role in the formation of underground water is anticipated by moisture condensation in fissured-karst carbonate collectors. A series of ways is known for assessment of condensation moisture amount, which in such regions generally does not exceed first percents; condensation flow module, as shown by calculations, is up to 3-4l⁄s·km2. In some cases on annual basis condensation does not plan a significant role in water balance of karst massifs, amounting on average no more than 5%-7% of the total flow. Water balance preparation is of a special interest for practical use of karst water in the region under study. This is one of the reliable ways of calculation during evaluation of underground flow of the territory. At the same time two main difficulties arise during those calculations: correct determination of the area of balance site and obtaining of data on all elements of water balance, included in the design formula. The first difficulty requires implementation of a special geological-karstologic survey. Depending on local conditions, border of the design area can be erosion cuts, various lithologic and tectonic contacts and topographic divide lines. Using the water balance equation, the total amount of underground water could be evaluated. The total flow can be divided into components only in the case if there are data of actual observations of sources (springs) and water streams. The main difficulties we face are related also to insufficient or lacking data on underground karst spring flows, lacking observations of surface stream flows. All

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these significantly complicate separate determination of surface, underground and deep flows. And at last, determination of spatial distribution of underground water, including their concentrated movement ways, is very important. Solution of this task requires application of complex methods of investigation: first of all complexation of hydrological-hydrogeological methods with the results of aerial photointerpretation and field geophysical and biolocation methods. Key words: 1- Karst 2- Hydrogeology 3- Neka R. 4-Biolocation Subject definition To obtain the values of atmospheric precipitation (X, mm) we have used the data from meteorological stations located nearby. The X=f (H) diagrams have been compiled (where H- is the altitude of the site). With their help the average values for corresponding altitude zones have been obtained (with altitude interval of 100-200 m). The design values of falling precipitation have been determined as weight average. As weighting coefficient the areas of the singled out altitude zones have been assumed (they have been determined by large-scale topographic maps). Actual data on evaporation from soils and transpiration through vegetation for karst sites of the region are practically missing. Therefore, for calculation of evaporation we considered it more advisable to use empiric formulas and diagrams based on the existence of relatively close relations with different meteo-elements. A special analysis of articles published in publications of different countries showed that there are several tens of formulas and diagrams relating evaporation with precipitation, evaporability, with absolute and relative humidity, air temperature, saturation deficit, etc. Naturally, while selecting calculation methods, we based upon availability of meteorological data. In general, the values X and Y obtained by independent methods allowed determining the value of the total flow from the given karst massif:

Ytot = Ysurf .+Yundergr.+Ydeep.= X-Z (2) Dividing the obtained total flow into components is possible only in the case, if the data of actual observations of the sources (springs) and surface streams are available. The observation method and corresponding calculations are common. The main difficulties we are facing here are missing data on underground flows, karst sources, there are no long-term observations of major surface river runoffs, formed at the expense of flows from karst and non-karst massifs. All of the above mentioned makes it impossible separate determination of surface, underground and deep flows for individual karts massifs at this stage. Therefore, the design values obtained by us are to be considered as estimative and requiring results of more detailed and purposeful investigations, Table (1) and Table (2). Obtaining of new data for justified water balance calculations required implementation of complex works for organization of long-term permanent observations. These works shall include hydrological, hydro-geological and hydro-geophysical investigations with establishment of regime observation network with hydrometric equipment on springs and rivers. Only such kind of works will allow quantitative determination and characterization of underground and deep components of water balance of the territory under study and provision of recommendations for the efficient ways of practical use of underground waters for water supply purposes.

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Table (1): The components of Neka No.1 hydro geological zone balance equation

Annual amount M.C.M

Balance equation components NO

-

200 Km2 The area of Upper Cretaceous calcareous

formation 1

156

780 (mm) Annual rainfall average 2

83

415 (mm) Actual evapotranspiration 3

-

% 17 Flow coefficient 4

26.5

132.6 (mm) Runoff 5

-

% 29.8 Amount of rainfall penetration (%) 6

46.48

232.4 (mm) Rainfall penetration (Qin) 7

12.75

404.3 (L/S )

Springs discharge (QS) 8

1.36

262 (L/S ) Wells discharge (QW ) 9

12.6

399 (L/S ) Entering amount of on-ground water to the

zone (QRin ) 10

12.15

358.7 (L/S ) Outgoing amount of on-ground water from

zone (QRout ) 11

32.8

1040 (L/S ) Outgoing underground water plus storage (QG

) 12

Table (2): The components of Neka No.2 hydro geological zone balance equation

Annual amount

M.C.M

Balance equation components No

- 190 Km3 The area of Upper Cretaceous calcareous

formation 1

188.48 992 (mm) Annual rainfall average 2

89.3 470 (mm) Actual evapotranspiration 3

- % 27 Flow coefficient 4

50.92 268 (mm) Runoff 5

- % 25.6 Amount of rainfall penetration (%) 6

48.26 254(mm) Rainfall penetration (Qin) 7

8.45 268 (mm) Springs discharge (QS) 8

- - Wells discharge (QW ) 9

- - Entering amount of on-ground water to the zone

(QRin ) 10

4 127 (L/S ) Outgoing amount of on-ground water from zone

(QRout ) 11

35.81 1136 (L/S ) Outgoing underground water plus storage (QG ) 12

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Corresponding author: Estimating of soils abrasiveness along tabriz metro line 2

TABRIZ, IRAN

Batol headari, ebrahim asghari .E.mail address :[email protected].

Abstract Mostly the long tunnels are excavating with tunnel boring machine (TBM).soils and rocks types are important in tunneling with TBM. one of the risks easily overlooked by engineer and contractor alike are the effects of abrasive ground on the costs and schedule of a given project. one of the important parameters in such tunneling is abrasiveness of soils and rocks on TBM cutter heads .several well ackhowledged test and prognosis methods already exist for rock , however there is only very limited khowledge available to describe the abrasiveness of soil and its impact on soft ground TBMs. In addition to mineral composition , many other textural features however also influence on abrasivity . there are some methods for estimating of soils and rock abrasiveness. the important mineral of soils and rocks is quarts. Tabriz metro line 2 tunnel, about 20 km , will be located in alluvial deposits that consist of clay particles to boulders sizes about 50 cm. quartz mineral in soils, cobbles and boulders is the main material in the deposits of this project . for soils the situation is quite different there are only very few fest methods to describe the abrasive characteristic of soils .for estimating abrasiveness of cobbles and boulders CERCHAR test and for estimating abrasiveness of sandy soils, petrography and mineralogy carried out. The CERCHAR tests are showed that the cobbles and boulders are very abrasive. The earth pressure balance (EPB) shield method is well known in the tunneling world, but there are still unexplained processes which require more understanding. Mineralogy of sandy soils is shown the abrasive mineral (quartz) content is between 5 and 20%. Based on existence classification, the sandy soils are slightly abrasive to abrasive. This paper will examine approaches to this problem and suggest a new approach based on current project undergoing design .and addition introduction method assigns mint abrasivation soils and rocks , study performed for introduction abrasiveness along Tabriz metro line 2 . Keywords : abrasiveness , TBM ,Tabriz metro ,CERCHAR test , mineralogy , NTNU test Introduction The modern world we live in would be very different without these sub terranean constructions. They are of great importance_ not just in the densely populated regions of the world. Tunnel excavation using tunnel boring machines (TBM), has become increasingly common in recent years, despite the fact that precise evaluation of certain risks have not kept pace with the use of these machines. Risks easily. One of the risks easily overlooked by Engineer and Contractor alike are the effects of abrasive ground on the costs and schedule of a given project.Earth pressure balance, or EPB, is a mechanized tunneling method in which spoil is admitted into the tunnel boring machine (TBM) via screw conveyer (cochlea) arrangement which allows the pressure at the face of the TBM to remain balanced without the use of slurry. This has allowed soft, wet, or unstable

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ground to be tunneled with a speed and safety not previously possible. This paper will examine approaches to this problem and suggest a new approach based on a current project undergoing design. Discussion Defining wear It is said that the amount of machinery cuter heads rubbing has important roll in estimating designing and improving the time of project. By primary wear we refer to the expected wear on the excavation tools and surfaces such as drag bits, disc cutters, scrapers and buckets etc. Secondary wear, on the other hand, is an unplanned wear and occurs when the primary wear on the cutting tools described to hold or support the tools in place such as cutting head spokes or cutter mounting saddles and wear on other surfaces not anticipated by the designers and TBM manufacturers. In picture 1 illustrates the drill rubbing before and after repairing. Abrasively of soils in TBM tunneling While rocks effects on TBM tunneling are well known, less work has been done on soil abrasiveness and its impacts on soil abrasiveness and its impacts on soil abrasiveness and its impacts on equipment such as cutter heads. The authors describe the different parts of the TBM that can suffer damage and recommend steps to establish regular inspection and maintenance programs for soft ground TBM components. A bar chart shows different weathered granites and the disc cutter consumption associated with different ground conditioning .The authors recommend a more adjective set of measures for soil properties in order to permit TBM projects to be better managed. Illustrates in stance of tunneling by TBM machinery The most important factor _ not only in EPB tunneling _ is to balance the soil pressure at the cutter head by a counter pressure in the working chamber. To calculate the necessary counter pressure, various face support calculation programs are given, depending also on the soil type in situ .Why using soil condition in EPB tunneling To build up the necessary face support pressure, the soil has to be impermeable against air. Three main closed mode tunneling techniques were developed out of these principle demand: Air pressure TBM It is possible to work by air pressure, when the soil itself is nearly impermeable against the air. Slurry TBM The working chamber is filled with a betonies suspension, a big air bubble in the top of the working chamber controls the support pressure EPB TBM The working chamber is filled with the original soil , the turning cutter head is responsible for creating a homogeneous and impermeable soil paste. To obtain this soil paste, conditioning additives have to be used in most cases _ according to the soil type in situ. Sometimes only water is sufficient, more common is the use of Foam to create a pasty soil and to introduce a certain amount of air to obtain the necessary face support pressure.

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The earth pressure balance tunnel boring machine or EPB consists of a cutting chamber located behind the cutter head. This chamber is used to mix the soil + water + foam. It is maintained under pressure by the mucking system .The system consists of a screw conveyor whose speed .is controlled so that constant pressure inside the chamber is guaranteed. The material exits the screw conveyor via hatch that can be closed when the TBM is shut down.in TABRIZ metro line 2 EPB methods couldn’t results acetyl so we couldn't use this method in vast scale. Methods of discussion wearing TBM cuter heads Foam the foam used is surface _ active product (like liquid soap)mixed with water, then with compressed air, in order to obtain micro babbles of air surrounded by a fine, biodegrade addable and not readily washable membrane. The mixture resembles shaving cream. When mixed whit the excavated soil, the product has the same properties us Benton tic slurry. Ties cased that soil became soft then the amount of TBM tunneling rubbing will decrease with be coming soft of soil Determine experiments of rubbing in rock and soils. Vickers test Hardness is a characteristic of a solid material expressing its resistance to permanent deformation. Hardness can be measured on the MOHS scale or various other scales. Some of the other scales used for indentation hardness in engineering—Rockwell, Vickers, and Brielle—can be compared using practical conversion tables. It is important to note that hardness of a material to deformation is dependent on its micro durability or small-scale shear modulus in any direction, not to any rigidity or stiffness properties such as its bulk modulus. Scientists and journalists often confuse stiffness for hardness, and spuriously report materials that are not actually harder than diamond because the anisotropy of their solid cells compromise hardness in other dimensions, resulting in a material prone to spelling and flaking in squeamish or acicular habits in that dimension (e.g. osmium is stiffer than diamond but only as hard as quartz). In other words, a claimed hard material should have similar hardness characteristics at any location on its surface. MOHS division which illustrated in one table. Scratch hardness In mineralogy, hardness commonly refers to a material's ability to penetrate softer materials. An object made of a hard material will scratch an object made of a softer material. Scratch hardness is usually measured on the MOHS scale of mineral hardness. One tool to make this measurement is the accelerometer. In following you can observe some of results obtained from lithotomic studies and the determination of quartz percentage over floating rocks in alluvial deposition. In stance depth: 10-22 meter Stone name: conglomerate Crush _conglomerate to bolder seem 5-7 mm carbonate segmented casing. Average amount quartz 25-30 present .pitcher 2 illustrate the microscopy profile. CERCHAR abrasiveness test.In the CERCHAR test, a sharp steel indenter (hardness of 200 kg/mm2)of 90cone angle is applied to the surface of a rock specimen with static force of 70

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N. The steel point is then slowly moved on 10mm. this procedure is repeated five times in various direction son the rock surface, always using a fresh steel tip. The abrasivity of the rock is obtained by measuring with a microscope the resulting wear flat on the steel cone. The unit of abrasivity is defined as a wear flat of 0.1 mm diameter .Picture 4symbolic design from CERCHAR test machine. LCPC abrasivity The abrasivity test of the laboratories des points et chausses consists in measuring the weight loss of a steel plate rotating at 4500rpm for 5 minutes in 500g of rock which was previously crushed pieces of 4_6.3 mm diameter. The metal plate (25*20*5) presents a ROCK well hardness B 60_75.in the pincher 3 show symbolic LCPC test. Conclusion: Sandy deposits of line 2 TABRIZ metro containing plenty of stone, boulders which comprising of rubbing potentiality over cutter heads implements. Thesevolcano derived from Sahand mountains and are igneous. in addition to we can utter that they are arranged in very rubbing part of tunneling in TBM machinery. this mineral are one of the hardstand the most rubbing of sandy soils in case of studding quartz the amount of quartz in soils is estimated between 5-25 percent. To decrease amount of rubbing in this cutting implements we can use FOAM specially in residential regions we use from .and recently with using of covering from antis _rubbing sheets over cuter heads and also with altering of cutting angle the amount of rubbing can be decreased .

table1:Classification of minerals occur according mohs

TALK GYPSE CALSIT FLUORITE APATIT ORTOZ QAUARTZ TOPAZ CRONDOM DIYAMOND 1 2 3 4 5 6 7 8 9 10

Picther1: The amount of rubbing can be decreased

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Pitcher 2:with carbonate cement the 10 depth boring

Picher4: Symbolic design LCPCtest picher3: Symbolic design from cerchar test REFRENCE

ه سازمان قطار "قطار شهری تبريز 2گزارش مطالعات ژئوتکنيک پروژه خط ). "1387(پژوهش عمران راهوار -1 ، ارائه شده ب شهري تبريز و حومه

1: 000/100ياس به مق" نقشه زمين شناسي تبريز"، 1372سازمان زمين شناسي و اآتشافات معدني آشور، -2

زمين شناسی برای مهندسين،دکتر معماريان ،حسين - 3

4.ASTM (2006), "Standard Test Method for Resistance to Degradation of Small-Size Coarse Aggregate by Abrasion and Impact in the Los Angeles Machine",

5.Allen, Robert (2006-12-10), A guide to rebound hardness and scleroscope test, , retrieved 2008-09-08

6.Jeandron, Michelle (2005-08-25), "Diamonds are not forever", Physics World,

7.San-Miguel, A.; et al. (1999-05-19), "High Pressure Behavior of Silicon Clathrates: A New Class of Low Compressibility Materials", Physical Review 83 (25): 5290,

8.west g . rock abrasiveness testing for tunneling technical note.international journal of rock Mechanics &Mining Sclences 26,_151_160,1989.

9..Nilsen B., Dafi, F., Holzhauser, J. and Raleigh, P. (2007), "New test methodology for estimating the abrasiveness of soils for TBM tunneling", Rapid excavation and tunneling conference.

10..Plinninger, R., Kasling, H., Thuro, K. and Spaun, G. (2003) "Testing Conditions and Geomechanical Properties influencing the CERCHAR Abrasiveness Index (CAI) Value", Int. Journal of Rock Mech.

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Evaluation of Qanat Collapse Hazard in Mashhad City (Case study: the zone 11 of municipality of Mashhad, Iran)

Fahimeh Salehi1, Mohammad Ghafoori2, Golamreza Lashkaripour3, Naser Hafezi Moghadas4

1: M.Sc. Student of Engineering Geology, Faculty of Earth Sciences, Ferdowsi University of Mashhad [email protected] address: -E

2, 3: Professor of Engineering Geology, Faculty of Earth Sciences, Ferdowsi University of Mashhad.

4: Associate Professor of Engineering Geology, Faculty of Earth Science, Shahrood University of Technology.

Abstract Mashhad city has been developed in recent decades. The development of the city towards the routes used to be qanat well is one of the problems that Mashhad city is confronted. Today many of the qanats are under urban areas. These qanats become dry little by little because of successive droughts, developing of the city and drilling deep wells In order to supply water. Contemporary of developing the city, the qanats are filled with earth fill soils uncontrollably and this problem causes ground settlement, cracks and fissures in the ground and consequently damages of buildings and also cracking in the system of water supply. This problem is doubled in west areas of the city because of high buildings and high abundance of qanats in those areas. This paper deals with the main factors that cause qanat collapse. First of all the exact location of the qanats in the zone11 of municipality of Mashhad was studied. Then the main factors that influence the stability and performance of qanats were determined. These factors include: depth of qanat gallery, loading due to surface structures, land use, underground water table and geotechnical properties of the soil. Finally areas with the most potential of collapse hazard are introduced. The results can be used in planning for increasing the security level of buildings and structures in hazardous areas of the city. Keywords: qanat; Settlement; zone 11 of municipality of Mashhad; land use. Introduction Mashhad, the second big city in Iran, is the capital city of Khorasan Razavi province. It is located in north east of Iran. The area of the city is about 270 km2. The population of the city is about 2.5 million people. Every year 13 million people visit this city. More than 25000 qanat shafts were identified by evaluating aerial photos in Mashhad region that most of them are located in west areas of the city. Of course, nowadays most of them dried. In the recent years qanats were covered by buildings and streets due to development of the city toward the west. Geology Mashhad plain is divided into three zones. Kopet Dagh sedimentary zone, Ophiolite zone and Binalood metamorphic zone are from north to south respectively. It is located between Binalood and Hezar Masjed mountain ranges. From the hydrological viewpoint, the city is a part of Kashafrood River’s basin and it lies on young alluvial deposits of Mashhad plain. The study area includes the eleventh zone of municipality of Mashhad in western part of the city.

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The soil type in that part is mainly consisted of gravel and sand that are originated from the southwestern metamorphic mountain. Surface soil type map of zone 11 is shown in figure 1. Mashhad qanats in general Mashhad has arid and semi-arid climate so the water resource are limited. The maximum average annual precipitation in 24 hours is 33 mm [1]. Underground irrigation systems called Qanats were used in the past few decades in Iran due to scarcity of water [2]. Qanats which are the traditional water piping systems are consist of an underground tunnel connected to the surface by a series of shafts. The tunnel has a gentle slope. This system causes water that comes in to view on the surface by gravity force. The qanat system was used where there is no surface water and was originally invented by Iranians [3]. In last decades, high demand for fresh water and the technology of drilling of deep wells have been resulted in death of Kariz (qanat) civilization [4]. There are two groups of qanats in urban region; some of these qanats are active i.e. they have water. The next group consists of old qanats related to the past decades or even past centuries that are inactive. These old qanats are now dry and partially collapsed. In regions with collapsed qanats, construction is not safe and soil test is necessary [5]. In Mashhad region there are more than 100 qanat chains and 26278 qanat shafts that identified by using aerial photos with 1/20000 scale [6]. Bahr Abad qanat with 22 km length and 133 m depth of mother well is the longest and deepest qanat in Mashhad area. Figure 2 shows the qanat chains in the urban area of Mashhad. Most of their mother wells are located in the western and southwestern parts out of the city. Also, appearances (The place where water comes into view on the surface) are located in central part of the city [7]. Nowadays most of qanats shown in figure 2 are dry and inactive, except Pachenar and Ghasem Abad qanats that they are still active. There is a high density of qanat chains in the developing western part of city with high buildings. Ground settlement will be induced by qanat collapse in these areas due to structure loading and may cause some damage to structures and lifelines. On Andishe Street in Ghasemabad area (west of Mashhad) several ground settlement took place. Most of this damage is due to construction over hidden tunnels and access wells of old qanats [8]. Characteristic of qanats in zone 11 of municipality of Mashhad Study area lies between Chehelbaze floodway from the north, Azadee highway from the east, Vakilabad Boulevard from the south and Namayeshgah square from the west. Statistics show that 170941 people lived in this area in 1386. This population makes up 7.04% of Mashhad population. Zone 11 is not an old region in Mashhad but it grew rapidly in recent years. Urban aerial photos with 1/6000 scale in 1351 was used to determine the exact location of qanats in study area. Water-resources map of Mashhad plain that supplied in 1343 indicates 9 main qanat chains exist in study area their characteristics is shown in table 1 (khorasan Razavi Regional Water Company). Due to decline of groundwater level in Mashhad plain, many of these qanats are dry except Ghasem Abad qanat that recharge from mountain. Qanats in table 1 checked with qanats were seen in aerial photos. 31% of qanat shafts have 15-30 meters depth that located in the east of study area. 1.2% of them have less than 15 meters depths that belong to Ghasem Abad qanat

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and the others have more than 30 meters depth. Groundwater level map were drown to exploring the water table in study area and checking the depth of qanat gallery with water table (figure 3). Flow regime mainly is toward the west and topography slopes mainly is toward the east. In this area water level declined and it is between 60-90 meters from ground surface. Average depth of mother well in table 1 is about 60 meters so the location of water level is deeper than the depth of qanat gallery. So according this result the water table don’t have direct effect in saturation of soil in tunnels and access wells of qanats and inducing the qanat collapse. There is not enough data about ground settlement in study area so we have to use of defective or incomplete data from fire services. Ground settlement was used to determine its relationship with qanat density. 7 cases of ground settlement happened in the study area during 1375-1386. In figure 4, black points are a sign of qanat shafts and grey rectangles are a sign of ground settlement. All of the ground settlement except one of them (85% of these cases) located in area with high and very high density of qanat. Therefore we can conclude that the ground settlement occurrences are influenced by qanat density in study area. One of the main reasons of ground settlement is the qanat shafts and wells that filled with earth fill soil and fill material. In past years the soil mechanic tests did not carry out and construction done on the earth fill soils with low relative density and low shear strength. So nowadays, urban problems like ground settlements occur in these areas. Collapse hazard map Numbers of qanat shafts per area and land use are two factors that evaluated for qanat collapse zonation. Land use planning is the most important factors in control and management of urban project and it determines how to use of land with the mention of urban necessity [9]. The most hazardous area in this region is defined as blocks with an area of about 10000 m2 that contain more than three qanat shafts. It is apparent that the blocks without qanat shafts don’t have the collapsibility potential. Finally the region under study is classified into 3 risk groups according to land use such as 1) Low risk area. 2) Medium risk area. 3) High risk area. High risk area consists of residential areas with buildings that have more than 3 floors and also schools, hospitals, governmental buildings and historic-cultural centers. Highways and residential areas with medium density are classified in the second group. Low risk area includes residential areas with low density and green areas. Figure 5, shows the qanat collapse map of the region based on land use and qanat shaft density. Different classes that are shown in this figure are as follows: Class 1: No qanat shaft + low risk and medium risk and high risk. Class 2: 1-3 qanat shafts + low risk. Class 3: More than 3 qanat shafts + low risk. Class 4: 1-3 qanat shafts + medium risk. Class 5: 1-3 qanat shafts + high risk. Or More than 3 qanat shafts + medium risk. Class 6: More than 3 qanat shafts + high risk. Based on the results obtained, about 28% of the region belongs to class 5 and 6 where the highest potential of collapsibility is expected. Moreover qanats located on northwest of the study area are less than 15 m deep so the collapse and induced settlement is more probable. Also some foundational settlements have shown in this region.

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Conclusion Qanats were a sign of genius at hydraulic science that used by Iranians over centuries; but nowadays they have made problems in urban area. There is not exact location map of qanat in Mashhad and almost always the qanat location was ignored in urban project. The problem is doubled in developing part of city like west areas because of high buildings and high density of qanats in those areas. Most of qanats in Mashhad area are dry and the access wells of old qanats were filled by earth fill soil; as a result the qanats have disappeared over the years. Due to structure loading and ground water changes, their stability may be altered and collapse would occur. 2355 qanat shafts were fined by using aerial photos in study area. On the other word there is a qanat shaft instead of 70 inhabitants in this area; or there is a qanat shaft in each 7000 m2 area of zone 11. In Collapse hazard map of study area more than One-fourth of lands have a high risk of qanat collapse. 85% of land subsidence located in area with high and very high density of qanat. We suggest preparing a qanat location map in urban area. This map will be used in management of land use and urban development. Another suggestion is to use the geophysics methods for finding the disappeared qanat location. Acknowledgements: we express our thanks to research center of Mashhad Islamic council and fire services for their cooperation and help in data collection. References

1- Torshizee, H., 1385, “Problems arise from construction waste, earth fill soils and aqueducts in Mashhad area”, Theses for master degree, Ferdowsi University of Mashhad, (in Persian).

2- Rayhani, M. H. T, El Naggar, M. H. 2006. “Collapse hazard zonation of qanats in greater Tehran area”, Journal of Geotechnical and Geological Engineering, v. 25(3), p.p. 327-338.

3- Salih. A. 2006. “Qanats a unique groundwater management tool in arid regions”: The case of bam region in Iran, International Symposium on Groundwater Sustainability, p.p. 79-87.

4- Beckman, C.S., Weigand, P.C., Pint, J.J. 1999. “Old world irrigation technology in a new contact: Qanats in Spanish colonial western Mexico”, Antiquity, v. 73 (274), p.p. 440-446.

5- Hashemee Sahee, S. H., Hashemee Sahee, S. M., 1384, “Qanat, land subsidence and construction problems”, Proceeding of International Symposium on Qanat, Kerman, p.p. 701-707, (in Persian).

6- National Geographical Organization, 1345, Aerial photos (1/20000).

7- Ghafoori, M., Lashkaripour, G. L., Hafezi Moghadas, N., Salehi moteahed, F., Naseh, S., 1388, “The assessment of environmental problems derives from old qanats in Mashhad city” proceeding of the International Conference on Water Resources, Shahrood, (in Persian).

8- Hafezi Moghadas, N., Ghafoori, M., Qezi, A., 1386, “Old qanats problem in Mashhad”, Proceeding of the Fifth Conference on Engineering Geology and Environment, p.p. 531-536 (in Persian).

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9- Esfandiyaree, A., 1388, “Evaluation of quantity of achievement detail project in Mashhad (Case study: the zone 11 of municipality of Mashhad)”, Theses for master degree, Ferdowsi University of Mashhad, (in Persian).

Table 1- zone 11 qanat chains characteristics visited in 1342 (khorasan razavi Regional Water Company)

Figure 1- surface soil type map of zone 11 of municipality of Mashhad

Figure 2- qanat map in Mashhad area

Figure 3- groundwater level map

Figure4- ground settlement map of zone 11 of municipality of Mashhad

Figure 5- collapse hazard map of zone 11 municipality of Mashhad

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SALT WATER INTRUSION MODELING OF AN AQUIFER IN THE NORTHWEST OF MAHARLU LAKE

F, Ghader & M, Zaree

Department pf Earth Science, Shiraz University [email protected]

Abstract The objective of this research is preparation a saltwater intrusion model for a coastal aquifer in the northwest of Maharlu lake Sout-East of the city of Shiraz, where the coastal aquifer is the single supply source of fresh water for irrigation. The saltwater intrusion from the lake has been widely caused the deterioration of the water quality. In this study, the SEAWAT-2000 computer code, a three dimensional finit difference model, used to study the intrusion mechanism and the groundwater system. After data collection including qualitative and quantitative data and geology and hydrogeology of the study area in the field, a conceptual model were prepared. On the basis of collected data, condition of the aquifer in February 2008 were taken as the initial condition and the length of calibration and verification periods consequently were taken 150 and 121 days after this time. After model calibration and verification, the aquifer conditions for the next year is predicted considering the following strategies : 1. The present condition for the next year, and 2.higher of Lake water level during the next year. However, with the constructed model, other strategies could be tested base on the more likely situation.

Introduction Coastal aquifers are important supply sources of fresh water in numerous area of the earth. The problem of saltwater intrusion has been widely caused the deterioration of water quality in these sources. As fresh water flows from the aquifer towards the coastline an aquilibrum condition will be estabilished between saltwater and freshwater. The installation of pumping wells within the coastal aquifer will to disturb this equilibrium and if the extraction rate is too large, it could cause adrop in the water table and will decrease the amount of freshwater towards the shoreline and increases the amount of saltwater flow from the shoreline towards the fresh water aquifer. Various case studies of sweater intrusion have been published in the past decades for example, the relation between sea-level changes and saltwater/freshwater interface has been studied for the aquifers in the North American coastal plain (Meisler et al. 1984), New Jersey(Navoy 1991; Lennon et al . 1986). Mahasa and Nagaraja (1996) discussed the general relation between groundwater recharge and seawater intrusion applying the Gyben-Herzberg equation, Ranjan et al (2006) applied a numerical model based on the sharp interface assumption to analyze the effects of climate change and land use on coastal groundwater resources in Sri Lanka. This paper described a salt water intrusion modeling for a coastal aquifer in the Northwest of Maharlu lake. Maharlu Lake is a salt lake located 27 km southeast of Shiraz (Fig 1 shows the location of the study area) . There are many fresh coastal aquifers around this lake that naturally are

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recharged by fresh water entering from the landward karstic aquifer. The hydraulic equilibrium could be disturbed due to large extraction rate and consequently dropping in groundwater table level. In consequence, the lake saltwater with high salinity (Ec more than 300ms/cm in summer) could flow towards the freshwater aquifer. The salinity of this lake salinity is much more than the oceans salinity, therefore the aquifer salinity could change very much even with a low equilibrium disturbance. For this reason, the management and maintenance of this aquifer is very difficult and important.

Method of study The main purpose of this work was the prepared saltwater intrusion model and determine the interface zone between salt and freshwater. With this aim the SEAWAT-2000 computer code was chosen as a salt and density- dependent ground water flow simulator. This computer code contains considerably more functionality than the piror released of version. This code was chosen primarily because it compares well with other density-dependent flow models in terms of the accuracy and execution time.In fact, new solvers for the flow equation (Hurbaugh et al. 2000; Mehl and Hill 2001) that may reduce model execution times is part of model codes. A finite-difference grid comprise a uniform cell size of 35 by 35 meters and 43 row and 45 columns. Boundary condition were assigned to the model domain based on the general knowledge and field data wich includs a constant- head and constant-salinity boundaries of the lake boundary. A constant flux of ground water, representing general flow of the ground water towards the coast originating from the karstic formation in the North of the aquifer. (Fig2, showes the isopotantioal map and position of the pizometer and wells). Aquifer properties including effective prosity, hydraulic conductivity, longitudinal dispersivity and etc. based on the field data and general knowledge is used. The collected data, condition of the February 2008 were taken as the initial condition. Model calibration is achieved through a trial-and error approach by adjusting the zonation and the values of four key parameters : TDS)kg/m3), hydraulic conductivity, recharge rate, effective porosity and dispersivity. In result of the model calibration the hydraulic head and concentratin(TDS) values calculated by SEAWAT model matched with the observed values to a satisfactory degree. Calibration and verification periods were chosen to be 150 and 121 days respectively. Fig3(a, b) illustrate scattered diagrams between observed and calculated head and concentration values for calibration period. Fig (a, b) showes scattered diagerams after verification. Fig5(a, b, c) show the zonation of hydraulic conducitivity, effective prosity and dispersivity values of the aquifer materials. Constructed model also showed the good fit between observed and calculated values after calibration and verification periods, Fig6(a, b). In order to determine the interface location across the lake saltwater and freshwater aquifer (A-A') longitudinal cross section the model was ran for February and July 2008 and the results are shown in Fig6(a, b). The Fig 6a showsthe result for February 2008 that the interface is streched up to 600m inward to the aquifer. Fig 6b shows the interface zone up to 400m from the lake line for July 2008. The reason that the interface zone is shorther for the month July in compare with the month of February, inspite that the ground water extraction is higher in summer season(July), in that during this time the lake water level decreases substantidly due to the high evaporation rate and lower discharge to that.

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Conclusion The purpose of this study was to construct model to aid in management of the groundwatr rsources of the coastal aquifer in Northwest of the Maharlu lake from the futur contamination by seawater intrusion. For this purpose a three-dimenional numerical model of density-dependent groundwater flow and misicible salt transport is developed to assess the current extent and predict the future condition of the lakewater intrusion in the study area. The model incorporates regional geologic, hydrogeologic feature and field data. The SEAWAT codeused in this study, well producted the model and simulate the condition of the aquifer in realation to the lake water. After clibration a reasonabaly good match between observed and calculated head and concentration was achieved. Interface was located in about 400 to 600m from the coastline in dry and wet seasons. The model prediction shows that future water level and concentration decrease, if all condition remain the same as those for July 2008 (afetr 1 year) due to lack of precipitation in this year salt water moves toward the lake. Refrences

1. Langevin, C. D, (2001), Simulation of groundwater motion discharge Biscayne Bay, Southeastern Florida:U. S. Geological Survey Water-Resources Investigatins Report 00-4251, p127.

2. Lin. J & Zheng (2008), A modeling study of seawater intrusion in Alabama Gulf Coast, USA, Springer

3. Ghader, F (2008) Saltwater intrusion modeling of an aquifer in the northwest of Maharlu Lake, Msc thesis, Shiraz university

4. Shoemaker, B.(2004). Important observation and parameters for salt water intrusion model.J.Ground water.Vol.42, PP.829-840

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Fig1: Location of study the are Fig 2: Isopotentional map(February 2008) and distribution of piezometer and pumping wells

Fig 3: Scatter diagram showing the goodness of fit between the abserved and calculated head(a) and concentratin ((b)for calibratin period

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a b

Fig 4:Scatter diagram showing the goodness of fit between the abserved and calculated head(a) and concentratin after(b) verification of model

Fig5: Hydarulic parameters after calibration (a): hydraulic conductivity (b): storage coefficient and(c): dispersivity

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a

b

Fig 6: The result of model calculaton showing the interface of lake and aquifer waterfor February2008(a) and July 2008(b)

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Investigation of geology condition and hydrogeology Kuhdasht area, Lorestan province, Iran

F. Hakimi1, A. Ahmadi-khalaji2, T. Dolatsha1, H. Mollaei3, V. Shahrokhi4

1. Islamic Azad University, Khorramabad Branch and member of young researchers club

2- Department of Geology, Faculty of Sciences, University of Lorestan

3. Islamic Azad University, Mashhad Branch

4- Islamic Azad University, Khorramabad Branch

Abestract The studied area lies 33° 25' - 33°45' N and between 47° 10' - 47° 45' E and located in Folded Zagros Zone. Water resources underground of Kuhdasht zone are depth well, low depth well and springs. The investigation of chemical quality based on chemical analyses different part show that these sources are good quality and suitable for agriculture and drinking consumptions. Over exploitation of water ground aquifer in recent year occurs conditions critical in water bearing formations and fall on water ground table. This critical condition in water bearing formation and carbonates formations in Kuhdasht area cause that necessary to draw of karstic Asmari-Shahbazan formation for Kuhdasht city water providence. Over salty-chalk formation Gachsaran of karstic Shahbazan-Asmari influence to water source quality. The effect of this formation depended on erosion or outcrop its in area. So, Gachsaran formation in this area is problem and basic factor in bitterness and salty water resource Asmari-Shahbazan formation. The studies of area show that this formation involved of high erosion and low influence of water resource karstic and provide EC suitable content for drinking uses. So, providence of water in Kuhdasht city is possible to karstic Shahbazan-Asmari formation. Key words: Kuhdasht, Zagros, karstic, ground water, Asmari Introduction Kuhdasht is located in Lorestan province, 85 km far from Khoramabad, 47,10' – 47,45’ E and 33,25’ – 33,45’ N , with 1197m average height (Fig 1). At the present time, Kuhdasht’s water is supplied by deep alluvial wells made in Kuhdasht plain. Over exploitation during the process of urbanization, as well as, penetration of urban drainage into underground water tables in recent years has headed towards a critical condition in the alluvial water tables in Kuhdasht plain. This critical condition, quantitatively and qualitatively, as well as, the presence of hard carbonate formations around kuhdasht have arrested the attentions towards the lime in the area in order to supply mid term water in Kuhdash, which has been studied in this research.

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Stratigraphy and geological setting The area is classified geologically as a part of the Folded Zagros Zone. Constructing the structure of the area, the upper Alpine rock making movements (Mohajjel and Fergusson, 2000, Mohajjel et al., 2003) have induced the folds as syncline and anticline structures with NE-SE trends (Farhoudi, 1981 Alavi, 1994, Berberian and King, 1981). The formations of the area are present in most of these folds which are according to their ages as follows: Gourpi, Amiran, Talezang, Kashkan, Asmari – shahbazan, Gachsaran and Quaternary alluvial. Hydrogeologic features of the formations Gourpi formation: This formation is considered as impenetrable classes respecting development of marl layers in it, and they are observed invaluable from viewpoint of underground water. Just limed Imam Hassan formation has solubility property and secondary porosity because of having high carbonate percentage; however, it does not have considerable value due to trail of the karstic water reservoirs. Amiran formation: The weak penetrability is one characteristic of this formation; the other characteristic is the great amount of current surface water. Being too weak respecting the amount of water output due to development of marl – siltstone and shale layers, this formation connot form favorable and full of water layers, also, it, generally, is too considerably weak to form underground water reservoirs. Talezang formation: The presence of primary porosity, besides, the function of secondary geological processes has expanded substantially its karstic penetrability. The calculation of the formation current water amount does not show a great deal. The formation has had a favorable development in the southern part of Kuhdasht plain; however, it has not been regarded as a prior source of water for supplement of Kuhdasht’s requirements, because of lack of any stream or pool with considerable water, also, its low thickness, as well as, respecting the presence of the limed formation, Asmari, in Kuhdasht area. Kashkan formation: Having no considerable value respecting the underground resources of water, the formation can function as rock of floor in Asmari – Shahbazan formation reservoirs in the bottom of it in some part of the area, because of its location under the latter formation. Asmari – shahbazan formation: The phenomenon of karst has developed a great deal in this formation, because of the presence of slits and holes and a high degree of porosity in it, and the most progressive karstic steps of these carbonate rocks can be found in the studied area (Aghasi, 1999). The quality of Asmari – Shahbazan karstic water reservoirs are affected overtly, because the salty – chalky Gachsaran formation is located upon it, and it has different effects, whether the salty - chalky Gachsaran formation has completely its manifestations in the area or it is eroded. Gachsaran formation is completely eroded in the studied area, therefore, it is anticipated that Gachsaran formation karstic water reservoirs will have enjoy appropriate amount of EC for being drunk. Thus, there can be possibly a proper option for supplement of half-time water in Kuhdasht via karstic - limed Asmari – Shahbazan formation. Gachsaran formation: Being problematic regarding underground water, this formation chiefly causes the bitterness and salinity of Asmari – Shahbazan underground karstic alluvial water. It shows low degree of penetrability due to development of marl layers and tiny – grained sediment in it, and has rather a large amount of current surface water. Gachsaran

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formation, having a high degree of sensitivity to erosion, So the water passing through the sediment can easily dissolve different kinds of salts in it, and when they enter to the lands, they can pollute the surface or underground sources of water. Fortunately being eroded in the studied area, the formation does not have much impact upon the karstic water reservoirs. The calculations show that the amount of Mercury and Arsenic is zero in the area’s water and the amounts of the other elements are: Plumb (-7.62-1.38 mg/lit), Chrome (13.47-32.29 mg/lit), Copper (0.6-4.30 mg/lit), Zink (3.15-26.43 mg/lit). Geology and hydrology This section’s objective is the study for determination of the physicochemical quality of the area’s karstic water resources, the variation’s features of water qualitatively in the process of the research, and determination of limitations in water consumption both for drinking and culture. The study and analysis of chemical quality of the area’s karstic water resources is based upon the chemical results of the last picked up samples of water during the research, some parts of which have been carried out in Lorestan organization of water and the other parts performed by Kermanshah nuclear absorption system. Since the analysis of chemical quality of water have its own complexity, the displaying techniques of qualitative water conditions are used for facilitation to access them. Sholer diagram is used for displaying the condition of drinking and Wilcox diagram is used for displaying the condition of cultural consumption of the area’s water. As mentioned, there is Asmari karstic formation in the studied area According to the chemical results obtained from the water samples picked up water samples, the conditions of the water reservoirs of the formation in the studied area have been shown by Sholer and Wilcox diagrams (Fig 2, 3). The samples are placed from good to acceptable from drinking viewpoint (Fig 1) and because of low sodium percentage (%Na)they are from excellent class, and from cultural uses viewpoint are placed in classes C2S1 and C3S1 (Fig 3). PH of the water samples are as the minimum level 7.4 and the optimum level 7.8 and the optimum amount of choler 14.7 mg/lit and the minimum amount of insoluble solid materials (TDS) 350 mg/lit and the maximum 529 mg/lit, which are reduced during the flowing. Also total hardness (TH) of minimum is equal to 270 and maximum is equal to 486 according to CaCO3 of standard level, so they are not problematic for drinking. Results Due to chemical data, the water of the area’s wells has high quality, but the kind of the contacting formations with the formations with karstic water reservoirs can affect upon the quality of the resources considerably. In some parts where there is the evaporated sediment, the quality has been reduced and it has made the anions of C1 and SO4 to be increased in their chemical syntheses, in fact, evaporating formation of Gachsaran is observed as a polluting, harmful, and adverting formation for the area’s karstic water. Generally, according to the results obtained from the studies, the area’s water resources do not have any limitation qualitatively for drinking and cultural uses.

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References

1- Aghasi, A. (1999). Karst Hydrology. Water engineering standards publishing, 397p.

2-Alavi, M. (1994) Tectonics of the Zagros Orogenic belt of Iran: New data and interpretations, Tectonophysics, 299, 211-238.

3-Berberian, M and King, G.C (1981) Toward a paleography and Tectonic evolution of Iran, Canadian journal of earthSciencs.18, 210-265.

4-Farhoudi, G (1981), A Compression of Zagros Geology to Island Arcs, Journal of Geology, 86,323-334.

5-James, G.A.and Waynd, J.d (1965) Stratigraphic nomenclature of Iranian Oil Consortium Agreement area. A.A.P.G BULLETIN 49, PP.2182-2245.

6-Mohajjel, M and Fergusson, CL.(2000)Dexteral Transpression in late Cretaceous Continental Collision, Sanandaj-Sirjan Zone, Western Iran. Journal of Structural Geology, 22, 1125-1139.

7- Mohajjel, M., Fergusson, C.L., Sahandi, M.R., 2003. Cretaceous–Tertiary convergence and continental collision, Sanandaj-Sirjan zone, Western Iran. Journal of Asian earth Sciences 21, 397–412.

8-N.I.O.C(1974)Geological Compilation map .Ilam-Kuhdasht , Sheet 20504.

9- Stocklin,J .(1968)Structural history and Tectonics of Iran : a review. A.A.P.G.Bulletin, 55, 1229-1258.

10-White, B.W (1977) Role of Solution Kinetics in the development of Karst aquifers .Karst and F .L.Doyle, Alabama, USA.

Figure 1: The geographic situation of Kuhdasht and the places of the studied area water resources.

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Fig 2: The chemical result of complete analysis of qualitative water resources in Kuhdasht, which shows that the water is from good to acceptable from drinking viewpoint.

Fig 3: The chemical result of Kuhdasht resources which shows that the water is from excellent classes from cultural uses viewpoint respecting having low sodium percentage, placed in classes C2S1 and C3S1.

Acceptable

Good

Bad

Unsuitable

Temporarily acceptable for drinking

Unacceptable for drinking

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Study of Hydrogeochemistry and Evaluation of the Groundwater Quality for Irrigation and Domestic Purposes in Marand Plain, East Azerbaijan

Fazel Khaleghi1*, Behzad Hajalilou2

Corresponding author: Islamic Azad University, Tabriz branch, Geology department, Tabriz. E-mail address: [email protected]

2Payame Noor University, Geology department, Tabriz, Iran. E-mail: [email protected]

Abstract To study hydrogeochemistry of groundwater, water samples were collected in an area of about 800 km2 and 87 locations from Marand plain, Eastern Azerbaijan province. Samples analyzed for major cations and anions and processed by statistical methods. Some of the locations are defined by higher concentration of EC, TDS, Cl, Na and K. Half of the groundwater samples posses Ca-Mg-HCO3 type of hydro chemical facies, followed by Ca-HCO3, Ca-Cl and Na-Cl types. Based on US salinity diagram, most of the samples fall in the field of C3-S1, indicating high salinity and low sodium water, which can be used for almost all types of soil with little danger of exchangeable sodium. Majority of the samples are not suitable for domestic purposes and far from drinking water standards. Comparing average electrical conductivity and total dissolved solids of the study area in the recent years revealed that declines in water levels with the extensive agricultural activities and urbanization resulting in the deterioration of groundwater quality in the major parts of the plain. Keywords: Hydrogeochemistry, Irrigation and Drinking, Water salinity, Marand plain Introduction It is estimated that about one third of the world's population use groundwater for drinking purpose [1]. Groundwater is the major source of water supply for domestic purposes because it was generally belief that groundwater is healthy and safer [2]. Groundwater is the only water source for domestic, industrial and irrigation uses in Marand plain and so it is really important to guaranty its quality for these different uses. Meanwhile it should be considered that the problems of ground water quality are more acute in areas that are densely populated and thickly industrialized. The quality of groundwater is the result of variety of processes and reactions. Geochemical studies could provide a better understanding of possible changes in groundwater quality as development progress [3]. Assessment of groundwater quality is the main factor which determines whether the water is suitable for domestic, irrigation and industrial purposes or not [4]. The study area is located between latitudes 38° 18'- 38° 46' N and longitudes 45° 15'- 46° 05' E. The region has a semi-arid climate and the average rainfall is 236 mm. Geologically, the area is overlain by young alluvial sediments and quaternary deposits but at the same time different rock units like igneous rocks, Miocene evaporation sediment and Miocene conglomerate affect the quality of groundwater (Fig.1), [5, 6, 9].

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Discussion 87 water samples from 74 water wells, 10 Qantas and 3 springs were collected in July and were analyses with standard methods in order to assess the groundwater chemistry and the variety of parameters that related to this factor. Sample locations were selected to cover the entire Marand plain. Furthermore, local surveys were done to determine probable contaminants in quality of water in the area. The results were evaluated with water quality standards given by the World Health Organization [7]. Groundwater chemistry Results of statistical analysis of physical and chemical parameters of groundwater such as minimum, maximum, median, mean and mode are given in Table.1. The EC values differs from 404 to 5580 (mho cm-1) and the mean value is 1827.7 mho cm-1. Values of pH are from 6.3 to 8.8 with an average of 7.70. This shows the neutral to alkaline nature of groundwater in the region. TDS values also vary from 242 to 3348 mg/l with an average value of 1096.6 mg/l. Hydro geochemical facies Geochemical evolution of groundwater was specified through plotting the concentrations of major cations and anions in the Piper diagram [8]. On the basis of Piper diagram, groundwater is divided into five facies including mixed CaMgCl types, CaHCO3, CaCl, NaCl, and CaNaHCO3 respectively (Fig.2). Therefore it is observed that alkaline earth (Mg2+ and Ca2+) exceeds the other cations and Cl- exceeds the other anions. Groundwater quality The chemical parameters of water samples compared with water quality standards [7] and public health standards for domestic uses. The cation concentration indicate that 12,40 and 6.9% of K+, Na+ and Ca2+ concentration exceed the standard limit of WHO. For chloride (Cl-) 16% of samples, shows more concentrations than maximum allowable limit for drinking water. High amounts of alkaline concentrations in western parts of Marand plain were associated to Miocene evaporation sediments [9]. The comparison of the average electrical conductivity and total dissolved solids from July 2005 to July 2008 indicates that the EC and TDS values had increased in the study area. Also, the unit hydrograph confirms that water levels have declined [6]. Decline in groundwater level due to over-exploitation of the aquifer in the Marand plain has caused the deterioration of groundwater quality in the major parts of the region. To ascertain the suitability of groundwater for different consumptions, it is essential to classify the groundwater based on their TDS values [10]. Approximately 55% of samples in the region are fresh water while the rest of the samples represent brackish water based on this classification. Only 19.5% of the samples have TDS less than 500 mg/l and can be used for drinking without any problem based upon classification of Davis and Dewiest [11], whereas only 2% are not suitable for irrigation purposes. Study of electrical conductivity of groundwater in Marand plain reveals that 48% of the samples are within the permissible limit (EC< 1500) and 40% of the samples fall in not permissible limit (EC=1500-3000). S.A.R (sodium adsorption ratio) is an important parameter for irrigation because it is a

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measure of alkali/sodium hazard to crops. The analytical data plotted on the US salinity diagram [12, 13], (Fig. 3) to determine groundwater suitability for irrigation purposes. Results show that approximately 42% of the groundwaters fall in the field of C3-S1, indicating water of medium-high salinity and low sodium and can be used for irrigation. However 26.5% of the samples fall in the field of C4-S2, indicating high salinity and medium alkalinity hazard. One sample comes under C4-S4 classification and may not be suitable for irrigation. Conclusion The hydrochemical analysis demonstrates that the groundwater in Marand plain is fresh to brackish water and neutral to alkaline in nature. The alkaline earth ions (Ca2+ + Mg2+) are more than alkaline ions (Na+ and K+) and value of Cl- is more than the other anions. This leads to a CaMgCl type of groundwater. However few groundwater samples represent CaHCO3 and NaCl types. Sodium value of groundwater in one third of the study area exceed the permissible limit for drinking and the TDS values in 29% of samples are higher than World Health Organization (WHO) standard and 40% of the samples are classified as not permissible based on Electrical conductivity. 42% of the groundwater samples are in the field of C3-S1 on the Wilcox diagram and can be used for irrigation in almost all types of soil with little danger of exchangeable sodium. SAR values and the sodium percentage (Na %) in locations indicate that majority of the groundwater samples are suitable for irrigation. Due to population and agricultural activities growth, the aquifer of the Marand plain is already being over-exploited which caused the salinity of groundwater and would be making it unsuitable for the domestic purposes and the irrigation of some lands in the study area.

Table 1: Statistical characteristics of different chemical parameters in groundwater of the region

Water quality

parameters

EC TDS pH Ca Mg Na K HCO3 CO3 Cl SO4

Numbers of samples

87 87 87 87 87 87 87 87 87 87 87

Mean 1827.7 1096.6 7.69 91.56 58.4 199.06 6.36 340.7 1.67 360.3 118.02 Standard deviation

1220.2 732.1 0.5 66.86 41.36 153.31 5.59 172.2 5.67 379.8 88.93

Maximum 5580 3348 8.8 336 218.4 798.1 29.64 945.5 42 1712.9 496.8 Minimum 404 242.4 6.3 17.6 4.32 6.67 0.04 100.65 0 8.8 4.8

Mode 984 590.4 7.5 66.4 39.36 184 3.9 183 0 443.7 48 Median 1514 908.4 7.7 67.6 45.6 172.5 5.07 305 0 221.8 96

All values are in mg/l except pH, EC (mho cm-1)

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Fig. 1 Geological setting of the study area and Sampling locations

Fig. 2 Piper diagram showing hydrichemical facies of groundwater

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0

2

4

6

8

10

12

14

16

18

20

22

24

26

28

30

32

Sodium ( alkali ) H

azard

Salinity Hazard

Sodi

um -

Ads

orpt

ion

- Rat

io (S

AR

)

Low

- S1

Med

ium

- S2

H

igh

- S3

V

ery

Hig

h -S

4

Low - C1 Medium - C2 High - C3 Very High - C4

250 750

Conductivity ( micromhos/cm (*106) at 25 oc )2250 10000100 5000

Fig. 3 Salinity and alkalinity hazard of irrigation water in US salinity diagram

Reference

1- Nickson, R.T. and etal., 2005, Arsenic and other drinking water quality issues, Muzaffargarh District, Pakistan. Appl. Geochem. p. 55-68.

2- Mishra, PC, Behera, PC. and Patel, PK., 2005, Contamination of water due to major industries and open refuse dumping in the steel city of Orissa-a case study. J. Environ. Sci. Eng., v. 47, no. 2, p. 141-154.

3- Arumugam, K. and Elangovan, K., 2009, Hydrochemical characteristics and groundwater quality assessment in Tirupur Region, Coimbatore District, Tamil Nadu, India. Environ Geol DOI 10.1007/s00254-008-1652-y.

4- Subramani, T., Elango, L. and Damodarasamy, SR., 2005, Groundwater quality and its suitability for drinking and agricultural use Chithar River Basin, Tamil Nadu, India. Environ. Geol. v. 47, p. 1099-1110.

5- Khaleghi, F. and Hajalilou, B., 2009, Investigation of hydrogeochemical factors and groundwater quality assessment in Marand Municipality, northwest of Iran: A multivariate statistical approach. Journal of Food, Agriculture & Environment (JFAE). v. 7, Issue 3&4, pages 930-937.

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6- Lashkaripour, G.R., Asghari-Mogaddam, A. and Allaf-Najib, M., 2005, The effects of water table decline on the groundwater quality in Marand plan, Northwest Iran. Iranian Int. J. Sci., v. 6, no. 1, p. 47-60.

7- WHO, 1993, Guidelines for drinking water quality: v. 1, recommendations, 2nd edn. WHO, Geneva, p. 130.

8- Piper, AM., 1994, A graphical procedure in the geochemical interpretation of water analysis. Am. Geophys Union Trans. v. 25, p. 914-928.

9- Asadian, A., Rastegar-Mirzayi, A., Mohajjel, M. and Hajalilu, B., 1993, Marand Geological Map: Tehran, Geological Survey of Iran. Scale 1:100000.

10- Freeze, RA. and Cherry, JA., 1990, Groundwater: Printice-Hall, New Jersey.

11- Davis, SN. and DeWiest, RJ., 1966, Hydrogeology: Wiley, New York.

12- US Salinity Laboratory Staff, 1954, Diagnosis and improvement of saline and alkalis soils. US Dept Agric Handbook, no. 60, p. 160

13- Wilcox, L.V., 1955, Classification and use of irrigation water, US Department of Agri., Circ. 696, Washington, DC.

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A Geotechnical Investigation of the Effect of Grain Size and Texture of Calcareous Rocks on Their Engineering Behaviour

G. R. Khanlari*, L. Ahmadi**, P. Lennox***, S. D. Mohammadi*

*Dept. of Geology, Faculty of Science, Bu Ali Sina University, Hamadan, Iran Email: [email protected]

**Postgraduate Student, Bu Ali Sina University, Hamadan, Iran

*** Dept. of Geology, School of BEES, Faculty of Science, NSW University, NSW, Australia

Abstract This paper examines the effect of the grain size and texture of calcareous rocks on their engineering behaviour with an emphasis on the texture of the rock. Aggregates are one of the most important construction materials in civil engineering, so their durability is critical to the long life of engineering works. The study of the effect of the size of aggregates leads to a new approach in the use of aggregates in order to achieve long life in engineering construction. Six different samples of calcareous rocks were selected from the regions of Hamedan province, Iran. The standard sulfate soundness test has been carried out on all samples and the weight loss of each sample was recorded. From the results, it was concluded that the grain size between 37.5 and 50 mm shows the best durability and quality of rocks and the grain size ranges between 4.5 to 12.5 mm shows the lowest durability and quality of calcareous rock samples in the sulfate soundness tests. Finally, the results show that there is a reasonable relationship between the texture of calcareous rocks and their durability, such that the rocks with a uniform and homogenous grain size and texture show a very good durability according to the sulfate soundness tests. Keywords: Aggregate, Engineering behaviour, Sulfate soundness test, Calcareous rocks, Grain size. Introduction Sedimentary rocks form more than 80% of the crust of the earth references. In this regard, calcareous rocks are the most widely distributed sedimentary rocks through the earth. From an economic and engineering point of view, aggregates are very important and are one of the most widely used construction materials in civil engineering projects. Normally, aggregates and other borrow materials are used in high volumes in engineering construction. For this reason, the study of the engineering properties and geological factors affecting the behaviour of calcareous rocks is very important, Kazi and Almansour, (1980). Figure 1 shows a map of the study area. Sampling has been undertaken based on Business, Transport and Housing Agency (1995), un-weathered and fresh samples were tested. From the thin section studies, it is clear that the texture of rocks can be used as the main factor in distinguishing calcareous rocks. Sulfate soundness tests have been carried out on different samples according to the ASTM C88 standard, American Society for Testing and Materials (1996).

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Description of Textures of Calcareous Rocks The study of the textures of different types of calcareous rocks has been carried out on the thin sections from different type of rocks. In order to recognize dolomites within the thin sections, they were painted with red alizarin liquid, Gupta and Seshgiri (2001). Figures 2, 3, 6, 7, 14 and 15 show the thin sections of six different samples of calcareous rocks from Hamedan province, Iran. The results of texture studies are presented in Table 1. Dunham, (1962) and Folk, (1962) have proposed some useful classifications for calcareous rocks. Dunham,s classification is mainly based on texture and environmental deposition. Since, the main aim of this research was study of textures of calcareous rocks and their effects on the engineering behavior of calcareous rocks; therefore Dunham,s classification has been used. As is clear from Table 1, all six samples have different types of textures. The samples from Nahavand (No: 1) contain crushed micrite grains with sparry cement. The texture is that of a brecciated calcareous. The samples from the Malayer area (No: 2), show a texture type of crystalline calcareous containing some calcite, quartz, and also some opaque minerals (pyrite and chalcopyrite), and cherts. Samples from the Hamehkasy area (No: 3) show a bioclastice packstone texture and contain reef and crinoid’s pieces. Samples from the Ali-Sadr region (No: 4) show a dolostone texture and contain large crystal of dolomite and quartz. The Abshineh samples (No: 5) show a bandstone reefy texture and contain reef pieces accompanied by micrite mud and cement. The samples from the Ekbatan Dam (No: 6) the texture is that of a calcareous conglomerate. The conglomerate contains pieces of calcareous which are slightly metamorphosed with spary cement. The results of the petrographic studies of the six different selected samples of calcareous rocks are shown in Table 1. Results from Sulfate Soundness Tests It should be noted that according to ASTM C88, the size of aggregates selected for the sulfate soundness test should be accordance with Table 2. In the sulfate soundness test, the sizes of aggregates are classified into seven groups. The biggest size (65 mm) is group one (G1) and the smallest size (4.75 mm) is group seven (G7). A: Results for the Nahavand Samples All samples selected from Hamadan province were prepared according to ASTM C88 standard, Ameraican Society for Testing and Materials (1996), into seven group sizes. The first groups of samples which have been tested were the Nahavand samples. Figures 2 and 3 shows the thin sections of Nahavad samples. The results of sulfate soundness test on the Nahavand samples (Brecciated calcareous) are presented in Figures 4 and 5. From Figures 4 and 5, the largest decrease of weight during the sulfate soundness test has been seen in the samples with 4.75 to 9.5 mm grain sizes (G7). This means that, from the seven groups of grain sizes, this group is most susceptible to weight loss in comparison with the other six sizes. On the other hands, the lowest decrease of weight has been recorded in samples with 37.5 to 50 mm grain sizes (G2). B: Results for the Malayer Samples The results of thin section studies on the Malayer samples are shown in Figures 6 and 7. This shows that these samples are crystalline calcareous sometimes with minor quartz grain. In addition, the results of five cycles of sulfate soundness test on the calcareous rock samples

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from Malayer are shown in Figures 8 and 9. It can be concluded that the largest decrease of weight has occurred on samples of 4.75 to 9.50 mm grain sizes (G7) and the lowest decrease of weight has been seen in samples of 37.5 to 50 mm grain sizes (G2 in the magnesium sulfate test) and samples of 25 to 37.5 mm grain sizes (G3 in the sodium sulfate test). It seems, sizes between 25 to 37.5 mm and 37.5 to 50 mm are most resistant to the sulfate soundness test and sizes below that and above these sizes have the lowest resistance to the sulfate soundness test. It means, the grain size is an important parameter affected to the durability of calcareous rocks. C: Results for the Hamehkasy Samples From thin-section study of the texture of calcareous rock samples from the Hamehkasy calcareous, it was found to be a bioclastic packstone texture. The Hamekasy calcareous is a white and porous calcareous with special engineering properties. Figures 10 and 11 showed the results of thin section studies on the Hamehkasy calcareous. Figures 12 and 13 show the results of sulfate soundness test. As is clear from Figure 12, the Hamehkasy samples show the largest resistance to weight loss in grain sizes between 4.75 to 19 mm (Groups 5 to 7) and lowest resistance to weight loss in grain sizes between 37.5 to 65 mm (Groups 1 to 3) in magnesium sulfate soundness test. Figure 13 show the largest resistance to weight loss of calcareous samples from Hamehkasy in grain sizes between 4.75 to 19 mm (Groups 5 to 7) and lowest resistance to weight loss in grain sizes between 37.5 to 65 mm (Groups 1 to 3) in sodium sulfate soundness test. D: Results for the Ali-Sadr Cave Samples Thin section studies from the Ali-Sadr cave samples show that the texture of the Ali-Sadr samples is a type of Dolostone Zonotopic. Figures 14 and 15 show the results of thin section studies on the Ali-Sadr cave calcareous rock samples. From the engineering properties studies it was concluded that Ali-sadr calcareous is a very compact calcareous and shows very good engineering properties. Figures 16 and 17 show the results of these tests. As is clear from Figures 16 and 17, the largest decrease of weight has occurred in grain sizes between 4.75 and 9.5 mm (G 7) for both tests and the lowest decrease of weight is recorded for grain sizes between 4.75 to 19 mm (Groups 1 to 3) in both tests respectively. E: Results for the Abshineh Dam Samples The results of thin section studies from the Abshineh Dam samples show that this type of calcareous rocks has a reefy boundstone texture. Figure 18 shows a photomicrograph of a thin section of the Abshineh dam sample. A part of a reef is in the centre of photomicrograph which is confined within the calcareous cement. Sodium and magnesium sulfate soundness tests were carried out on the Abshineh Dam samples in 5 cycles of wetting and drying. Figures 19 and 20 show the results of the sulfate soundness test. F: Results for the Ekbatan Dam Samples Dam is constructed near the boundary between the calcareous and metamorphic rocks and recently it has been raised (25m) in order to increase its storage capacity. The results from thin sections studies show that the texture of these samples is a calcareous conglomerate. Figures 21 and 22 show photomicrographs of calcareous rock samples from the Ekbatan Dam. Results from the sulfate soundness test show that the largest decrease in weight was in the size ranges between 9.5 to 12.5 mm and the smallest decrease in weight has occurred in size ranges between 25 to 37.5 mm in the magnesium sulfate soundness test (Figure 23). Also the

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smallest decrease in weight was recorded in size ranges between 50 to 63 mm and the largest decrease in weight has occurred in size ranges between 9.5 to 12.5 mm in the sodium sulfate soundness test (Figure 24). Conclusions In this research, general tendencies of the sulfate soundness test results have decrease tendency. The uniformity of rocks caused the results tendency of Malayer and Ali-sadr samples are reversed manifest tendencies. This tendency is acceptable for Abshine Dam samples as well. Regarding to heterogeneity of the Nahavand, Ekbatan Dam and Hamekasi samples, the sulfate soundness test results haven't reversed manifest tendencies. Also, the lowest weight decrease of Hamekasi samples during soundness tests has been seen with finer grain sizes (G5 and G7). It could be described that the durability strength of fossil particles is more than the welded particles from the same fossils. For all samples (except Hamekasi samples) the lowest weight decrease during soundness tests has been seen with G2 grain size (37.5 to 50 mm) that could be optimized size against corrosion. Consequently it can be concluded that, before using calcareous rocks as aggregates or as borrow materials, their texture and grain size should be studied carefully. References

1 - American Society for Testing and Materials, 1996, Standard Test Method for Soundness of Aggregates by Use of Sodium Sulfate or Magnesium Sulfate: ASTM C88-90.Annual book of ASTM Standards, v. 14.

2- Business, Transportation and Housing Agency, Department of Transportation, Engineering Service Center, 1995, Method of Test for the Soundness of Aggregates by use of Sodium Sulfate: California Test, p.214.

3- Dunham, R.j., 1962, Classification of Carbonate Rocks According to Depositional Texture: Amr. Assoc. Petrol. Geol. Mem. No. 1, p. 108-121.

4- Folk, R. L., 1962, Spectral Subdivision of Calcareous Types, In: Ham, W.E., editor, Classification of Carbonate Rocks: A Symposium. Amr. Assoc. Petrol. Geol. Mem, No.1, p. 62-84.

5- Gupta, A.S., Seshgiri, K., 2001, Weathering Indices and Their Application for Crystalline Rock. Bull. Eng. Geol. and Env. v. 60, p. 201-221.

6 - Kazi, A., Almansour, Z.R., 1980, Influence of Geological Factors on Abrasion and Soundness Characteristics of Aggregates: Eng. Geol, v. 15, p. 95-203.

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Table 1: The results of thin section and texture studies for carbonaceous rocks.

Sample No:

Name of the study Area

Description of Rock Texture of the rock (Dunham, 1962)

Texture of the rock (Folk, 1962)

1 Nahavand crushed micritic limestone pieces with spary cement

brecciate limestone

2 Malayer calcite crystals, quartz, opaque minerals, chert and muscovite

crystalline limestone

3 Hamehkasy reef pieces with crinoids and algae bioclastic packestone

4 Ali-Sadr Cave large crystals of dolomites and quartz dolostone

5 Abshineh Dam reef pieces and muddy micrites with micritic cement

reefy bandstone

6 Ekbatan Dam metamorphosed pieces of limestone with spary cement

conglomerate with limestone cement

Table 2: The percentages of particles within the each sample

Name of the study Area Sample No: Opaque (%)

Fossil (%)

Alluvial Particles (%)

Porosity (%)

Nahavand NA-1 1-2 - 5 2 NA-2 1 - 11 1-2

Malayer MA-1 - - 3 3 MA-2 1 - 10 1-2

Hamehkasy HA-1 - 50 - 35 HA-2 - 70 - 25

Ali-Sadr Cave AL-1 1 - 3 <0.5 AL-2 1 - 1-2 <0.5

Abshineh Dam AB-1 - >95* - 8 AB-2 - >95* - 4

Ekbatan Dam EK-1 - - - 5 EK-2 - - - 3

*Corral Boundstone

Table 3: Description of sizes used in Sulfate Soundness Test. Group G1 G2 G3 G4 G5 G6 G7

Size (mm) 50 – 65 37.5 – 50 25 – 37.5 19 - 25 12.5 - 19 9.5 – 12.5 4.75 – 9.5

Tehran MashhadTabriz

Shiraz

Caspian Sea

Persian Gulf

Dubai

UAE Oman Sea

N

Hamadan

CapitalSampling AreaImportant City

1 Location of the study area within the circle on the map. (from website:www.iranmap.biz)

Figure 2. Photomicrogarph of a thin section of the breciated limestone from Nahavand.

Figure 3. Photomicrogarph of a thin section of the the breciated limestone from Nahavand

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Figure 4. Results of magnesium sulfate soundness test for the Nahavand samples.

Figure 5. Results of the sodium sulfate soundness test for the Nahavand samples.

Figure 6. Photomicrograph of a thin section of a Malayer sample.

Figure 7. Photomicrograph of a thin section of a Malayer sample.

Figure 8. Results of magnesium sulfate soundness test for theMalayer samples

Figure 9. Results of the sodium soundness test for the Malayer samples sulfate

Figure 10. Photomicrogarph of a thin section of the Hamehkasy carbonaceous sample. Note the Alokoms within the limestone.

Figure 11. Photomicrogarph of a thin section of the Hamehkasy carbonaceous sample. The Alokoms are very clear within this sample

Figure 12. Results of magnesium sulfate soundness test for Hamehkasy samples.

Figure 13. Results of sodium sulfate soundness test for Hamehkasy samples

Figure 14. Photomicrogarph of a thin section of the Ali-Sadr Cave carbonaceous samples. On the right hand side there are dolomite crystals and on the left hand side there are quartz crystal within the limestone

Figure 15. Photomicrogarph of a thin section of the Ali-Sadr Cave carbonaceous samples. The upper right part of figure shows dolomite crystals and the lower left part of the figure shows quartz crystals within the limestone.

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Figure 16. Results of magnesium sulfate soundness test for the samples from the Ekbatan Dam area.

Figure 17. Results of sodium sulfate soundness test for the samples from the Ekbatan Dam area.

Figure 18. Photomicrograph of a thin section of the Abshineh Dam carbonaceous samples.

Figure 19. Results of magnesium sulfate soundness test for Abshineh Dam samples.

Figure 20. Results of sodium sulfate soundness test for Abshineh Dam samples.

Figure 21. Photomicrograph of a thin section of the Ekbatan Dam samples.

Figure 22. Photomicrograph of a thin section of theEkbatan Dam samples.

Figure 23. Results of magnesium sulfate soundness test for the Ekbatan Dam samples.

Figure 24. Results of sodium sulfate soundness test for the Ekbatan Dam samples.

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Engineering Geologcal Assessment of Alvand Granitic Rocks

G. R. Khanlari, M Heidari, H. Jafar-Gholizadeh

Dept, of Geology, Faculty of Science, Bu Ali Sina University, Hamedan, Iran Email: [email protected]

Abstract The purpose of this paper is to demonstrate the influence of lithology and weathering on the physico-mechanical properties of the Alvand granitic rocks. It also presents the results of engineering geology investigations carried out on the Alvand granitic rocks in southwest part of Hamedan, Iran. Studies were carried out both in the field and laboratory. Petrological studies have shown that there are different types of granite in Alvand granitic rocks including: porphyry granite, monzo-granite, holo-leucogranite and diorite. From laboratory testing it was concluded that the physical and mechanical characteristics of garnitic rocks are depend on their weathering degree. These results reflect the effect of the mineralogy on the engineering properties of granitic rocks. Keywords: engineering geology, granitic rocks, engineering properties, lithology, mineralogy Introduction The Alvand granitic rocks are the most abundant intrusive plutonic rocks in Iran. From a structural geological point of view, it is a very complicated igneous rock mass, because it was affected by several tectonic phases. Alvand granitic rocks methamorphed the adjacent Jurassic schists to hornfels. Throughout the history, granite has been used as a building stone and also shaped into rock reliefs, rock statues, bathing-tub, stone pavements and some famous monuments such as the inscriptions of Darius in Persepolis, Shiraz, and Ganjnameh in Hamedan, Iran respectively. Figure 1 shows one of the most important of the Persepolis memorials from the Alvand granitic rocks in Hamedan, Iran. Different parameters such as environmental (external) and inherent (internal) factors affect the engineering properties of rocks. One of the most important environmental factors affecting the engineering behaviour of rocks is weathering. Rock masses, on the other hand, are addressed in terms of rock strength and discontinuity characteristics (e.g., joints, faults, bedding and foliation) (Ehlen, 1991). Therefore, when we are using granitic rocks as a construction material, we have to study their engineering properties in order to understand their engineering behaviors under the loads and the surrounding factors. Geological Setting The study region contains a very complicated arrangement of igneous and metamorphic rocks with ages from Liassic to Late Cretaceous (Valizade et al, 1974). The Alvand granitic rocks are part of the Sanadaj-Sirjan zone which belongs to the main thrust of the Zagros in the western part of Iran. The petrology of the Alvand granite consists of five different types of granite (Sepahigreo, 1999). From an engineering geology point of view, these granitic rocks were divided into three main categories by Khanlari et al (2003). Figures 2 to 5 show some geological structures within the Alvand granites.

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General Characteristics of the Alvand Granitic Rocks The Alvand granitic rocks are usually light grey to white color and fine to coarse grained (2-5 mm in diameter). Petrographical study of the Alvand granitic rocks indicates that the main minerals are plagioclase feldspar (25%), orthoclase feldspar (30%) and quartz (25%), biotite (15%). The remaining 5% contains hornblende accompanied by lesser amounts of apatite, titanite, zircon, epidote and other opaque minerals. Weathering Characteristics The weathering state and weatherability of rocks are very important for engineering geology projects and to assess the useability of these rocks as building stones. The weathering state of rocks can be described by various chemical and petrographical indices. To determine the weathering state of a rock, a considerable amount of chemical analysis is required. In this research, the samples are subjected to chemical and petrographical analyses and also physical and mechanical properties testing. Weathering profiles were studied in a number of excavated sections in the study area. The weathering of the Alvand granitic rockds has been described by Gholizadeh, (2006) following the six stage classification schemes proposed by GSL (1995) as shown in Table1. Definitions of the grades of the weathering are classified by following the procedure suggested by The ISRM (1981). The Alvand granitic rocks exhibits a complete weathering profile from fresh rock to completely weathered rock and locally residual soil.Figures 6 to 8 show different photomicrographs of the mineralogy and textural characteristics of the Alvand granitic rocks (fresh and weathered samples). Description of Engineering Properties of Alvand Granitic Rocks The main objective of this research work was an assessment of the engineering properties of rock sample from the Alvand granitic rocks based on site investigations and laboratory testing. Variations in measured rock properties are due not only to the physical dimensions of the specimens used, but also to the testing equipment, test techniques, rate of loading and rate of displacement (Khanlari et al, 2005). Laboratory tests were carried out on different samples of rock from the Alvand granitic rocks to acquire data on the engineering properties of the intact rock. Many samples were prepared from the block rocks according to the ISRM, (1981). The most important physical and mechanical properties of intact rock granite (unweathered samples) obtained from the laboratory tests are presented in Table 2. For the whole rock analyses, the X-ray fluorescence (XRF) has been used to obtain the oxide content of the samples having different degree of weathering (Table 3). Conclusions The following results are achieved from this research: 1- Physical and mechanical properties of granitic rocks can be used as weathering indices and these are cheaper to perform the chemical indices. 2- Three different types of granitic rocks (holo-leucogranite, porphyritic granite and granodiorite) were recognized based on texture and fabric

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characteristics of granitic rocks as important factors with respect to their engineering geological properties. 3 – Physical and mechanical properties of weathered granitic rocks are varied extremely depending upon the degree of weathering. 4- Because of climate conditions in the study area (around 70 degrees changes between the highest and lowest temprature), there is a predominance of physical rather that chemical processes operating on the rocks, as indicated by the mineralogical and chemical analyses. References

Ehlen, J., 1991, Significant geomorphic and petrographic relations with joint spacing in the Dartmoor GraniteL: southwest Eng- land Zeitschrift fur Geomorphologie, v. 35, p.425–438.

GSL., 1995, The description and classification of weathered rocks for engineering purposes, geological society engineering group working party report: Quarterly Journal of Engineering Geology, v. 28, p. 207-242.

ISRM, 1981, Suggested method for determining water content, porosity, density, absorption and related properties, swelling and slake-durability index properties, in Brown, E. T., editor, Oxford: Pergamon Press, p. 81-94.

Jafar-Gholizadeh, H., 2006, The Study of Weathering Indices and Their Application on Alvand Granitic Rocks: MSc Thesis, Bu-Ali Sina University, Hamedan, Iran.

Khanlari, G.R., Sepahi-gero, A. A., and Sadr, A. H., 2003, Study of Engineering Properties of Alvand Granites, Research work, University of Bu–Ali Sina.

Khanlari, G. R., and. Mohammadi, S. D., 2005, Instability Assessment of Slopes in the Heavily Jointed Limestone Rocks: Bulletin of Engineering Geology and the Environment, v. 64 (3), p. 295 – 301.

Sepahi-gero, A.A., 1999, Petrology of Alvand polotunic with emphysis on granitoids: PhD Thesis, Tarbiat Moalem University, Tehrean, Iran.

Valizadeh, M.V., 1974, The study of petrology, chemist-mineralogy of Alvand batholith, Hamedan: Journal of science, Tehran University, v. 6, p. 14-29.

Table 1: Weathering classification for rock materials (GSL, 1995)

Grade Description Typical characteristics I Fresh Unchanged from original state II Slightly weathered Slight discoloration, slight weathering III

Moderately weathered

Considerably weakened, penetrative discoloration Large pieces cannot be broken by hand

IV

Highly weathered

Large pieces can be broken by hand Does not readily disaggregate (slake) when dry sample immersed in water

V

Completely weathered

Considerably weakened Slakes in water Original texture apparent

VI Residual soil Soil derived by in-situ weathering but retaining none of the original texture or fabric

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Table 2 Physical and mechanical properties of Alvand granitic rocks (Khanlari et al, 2003) Name of the sample

UCS (MPa)

IS(50) (MPa)

σt

(MPa) Dry density (gr.cm3)

Porosity %

Water absorption% (IV)

Moisture content%

Hololeuco granite

72.38 3.29 2.26 2.55 1.46 1.09 0.32

Monzogranite 136.49 6.20 7.41 2.65 0.94 0.5 0.05 Diorite 203.28 9.24 9.74 2.86 0.76 0.27 0.21

Table 3: Elemental composion obtained by XRF from the Alvand Granitic rocks samples

D = Porphyry granite H = Holo-leucogranite G = Granodiorite 0 = Fresh 1 = Slightly weathered 2 = Moderately weathered 3 = Highly weathered 4 = Completely weathered 6 = Residual soil LOI = Oxid content and loss on ignition

Figure 1. A very famous inscriptions of Darius in Ganjnameh,

Hamedan,Iran (2550 years ago).

Weathering grade of samples

SiO2 Al2O3 Na2O MgO K2O TiO2 MnO CaO Fe2O3 P2O5 LOI

D1 63.67 14.63 2.62 2.29 5.42 0.7 0.11 2.26 7.32 0.15 0.84 D2 63.42 14.82 2.45 2.08 5.20 1.05 0.12 2.17 7.48 0.12 1.18 D3 63.15 15.23 2.42 1.70 4.88 1.13 0.90 2.15 7.50 0.16 1.39 D4 63.31 16.65 2.34 1.63 4.81 1.25 0.11 2.13 7.51 0.15 1.62 D5 63.02 16.70 2.12 1.52 4.40 1.26 0.16 1.98 7.53 0.11 1.68 D6 62.68 16.76 2.01 1.51 4.15 1.30 0.19 1.73 7.54 0.13 2.00 H1 62.14 19.99 7.19 0.42 0.44 0.64 0.01 8.56 0.63 0.23 0.34 H2 62.12 20.14 7.13 0.38 0.34 0.69 0.01 7.74 0.68 0.32 0.42 H3 62.11 20.23 7.06 0.33 0.31 0.70 0.03 7.54 0.87 0.26 0.52 H4 61.46 21.01 6.94 0.25 0.28 0.72 0.01 7.52 0.96 0.03 0.67 H5 61.36 21.11 6.37 0.23 0.27 0.74 0.01 7.44 1.14 0.03 1.21 H6 61.26 21.32 6.22 0.17 0.22 0.84 0.02 6.89 1.12 0.07 1.55 GG11 68.07 13.21 2.04 1.55 6.00 0.69 0.08 0.88 5.78 0.13 0.53 GG22 01.68 27.13 98.1 5.1 6.5 71.0 1.0 83.1 23.6 17.0 63.0 GG33 01.67 52.13 94.1 46.1 2.5 94.0 12.0 55.1 55.6 11.0 61.1 GG44 66.57 13.72 1.87 1.36 5.05 1.00 0.09 1.55 6.65 0.09 2.05 GG55 66.49 13.98 1.80 1.35 2.78 1.22 0.18 0.56 7.00 0.11 3.53 GG66 66.08 14.08 1.76 1.31 2.51 1.85 0.10 1.49 6.98 0.19 3.65

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Figure 2. Illustration of the porphyry granite (G2) with an aplitic dyke.

Figure 3. Illustration of holo-leucogranite (G3) with oriented enclaves

Figure 4. Illustration of porphyry granite with

oriented feldspars and enclaves. Figure 5. Illustration of two orthogonal joints system in the Alvand granitic rocks. The C joints are horizontal and formed later than the L joints which are vertical.

Figure 6.a) Photomicrograph of fresh Porphyrtic granit , b) Photomicrograph of weathered porphyritic granite

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Figure 7.a) Photomicrograph of fresh granodiorite, b) Photomicrograph of weathered granodiorite

Figure 8.a) Photomicrograph of fresh holo-leucogranite, b) Photomicrograph of weathered holo-leucogranite In these photomicrographs, minerals are illustrated with: Pl = plagioclase, Or = orthoclase, Q = quartz, Bi = biotite, and Se = sericite.

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The Characteristic and Classification of Thermal Spring in Ramsar area, North of Iran

M,R,Ansari (Islamic Azad university ,chaloos branch).

M,BahramAbadi (Islamic Azad university, Tonekabon branch).

M,Nazeri (Islamic Azad university, Lahijan branch).

K,Ghorchibiki (Islamic Azad university, Tonekabon branch).

F,Abedsoltan (Islamic Azad uni, North Tehran branch).

ABSTRACT Ramsar area is located across and between Alborze Mountain and Caspine Sea in North of Iran. About 30 spas are located south of the Ramsar and Sadatshar town. They are almost in between 20 to 70 m elevation. Paleozoic, Mesozoic and Tertiary rocks and alluvial deposit are exposed around the Ramsar area. In tertiary, acidic Plutonism was active and intrusion into the Paleozoic and Mesozoic formations. Quaternary and Alluvium deposits are exposed and extending on the Jurassic formations in Ramsar plain and have thickness lower than 10 m in show springs. The annual precipitation in the Ramsar region is 976 mm.There has not any proper Thermal spring management in Ramsar area yet. This could post some serious problem on improper management of Thermal spring sites, where its environment has been put into jeopardy. This study aims to provide a way to classify the Thermal springs in Ramsar area. The result of this study help in the classification of Thermal spring sites for official planning improvement of administration and sustainable development of natural resources of the area.The study makes use of the Department Applied Geosciences in Islamic Azad University and GIS data of a total of 9 Thermal springs in the attempt to set up a classification system of Thermal springs in Ramsar area. These data include surface temperature, conductivity, alkalinity, acidity, TDS, pH values, Ca, Cl, Fe, K, Mg, Mn, Na, SiO2, SO4 contents, their locations, usages and other relevant information.The surface temperature of Thermal springs are between 19oC – 65oC and SiO2 geothermometer shows estimated reservoir temperature range from 86 o C – 96 o C. Most of the water from these Thermal springs is relatively turbidness and their composition is sodium choloride. The Thermal springs in this area generally exhibit high SiO2 and Na content; strong smell of sulfur. In addition, there are 30 Thermal springs located in Ramsar area and that show high concentration of Cl, Ca, Na, K and Mg.There are two major criteria used in the classification system in this study, temperature and their usage. On the basis of temperature, there are three classes of Thermal springs in Ramsar area: hyperthermal spring (10 %, 50-99o C); thermal spring (80%, 30-50o C). There are 4 types of usage classification: swimming pools, Tourism, space heating and drying of organic materials. There is one class achieved on the basis of pH values, all of Thermal springs exhibit weak acids. Keywords: Thermal spring, thermal water, chemical composition, classification

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1-INTRODUCTION Ramsar area is located across and between Alborze Mountain and Caspine Sea in North of Iran. About 30 spas are located south of the Ramsar and Sadatshar town. They are almost in between 20 to 70 m elevation. Paleozoic, Mesozoic and Tertiary rocks and alluvial deposit are exposed around the Ramsar area. Quaternary and Alluvium deposits are exposed and extending on the Jurassic formations in Ramsar plain and is composed of fan and debris deposits and have thickness lower than 10 m in show springs. The annual precipitation in the Ramsar region is 976 mm. In tertiary, acidic Plutonism was active and intrusion into the Paleozoic and Cenozoic formations. (Fig. 1) Khazar fault is normally and longest fault in south of Caspine sea, and has NW- SE trend, in junction locally fault with N-S trend and khazar fault thermal waters issue through these faults.(Ansari et al 2009) There are increasing of usage of natural resources due to the population growth rate and convenient instruments used in everyday life. So there will be serious problems on sustainability and environment. Geothermal resources are one of natural resources, thus sustainable management and wise-used are needed. It is necessary to have information of all geothermal resources in this area. These data provided by BPJprogramming (Bashgah Pazhooheshgaran Javan Islamic Azad university of Iran), investigation of thermal spring in Ramsar area. This paper will informs about thermal spring geological settings, geology, chemical characteristics of Thermal springs and some classifications of Thermal springs in Ramsar area. 2. CHEMICAL CHARACTERISTICS AND DISTRIBUTION There are a total of 9 Thermal springs in Ramsar area. The assay of these Thermal springs consist of surface temperature, conductivity, alkalinity, TDS, pH values, H2S, Ca, Cl, Fe, K, Mg, Mn, Na, SiO2 and SO4 contents. The detail of some items is as follow; 2.1 Surface Temperature:The temperature measured from a total of 9 Thermal springs range between 19C and 65o C. The average temperature is 44 o C. The Standard deviation (SD.) is 9 and median (or 50th %) is 45 o C. The Thermal springs which, temperature are higher than 65o C mostly located in Ramsar town, probably related to the fault system. 2.2 Alkalinity (HCO3):A total of 9 assay of thermal water show HCO3 content ranging from 442.86 and7731.08 mg/l. The average is 1499 mg/l, with an SD. of 24.8 and the median value of 785.56 mg/l. Thermal springs in the Western part of this area have HCO3 content higher than the median values. It may have been cause by the chemical reaction while thermal water flows through wall rocks which shale is bearing coal lens, limestone, dolometic-limestone and dolomite. 2.3 TDS (Total dissolved solids):The 9 thermal water samples have TDS contents between 1356 and 16720 mg/l. The average is 11210.11 mg/l; the median is 13500 mg/l. Most of Thermal springs in this area have high TDS (>1,500 mg/l) especially those Thermal springs located near the junction of NW-SE and N-S faults in Ramsar area. 2. 4 pH : The pH values of 9 Thermal springs show a range between 5.5 and 6, with an average of 5.8, the median value of 6. Most of Thermal springs are weak acid spring. 2.5 Ca, Cl, K, Mg and Na:The Ca content of thermal water has a range between 285948 and 3635254 µg/l. The average is 922999.7 µg/l with an SD, Of 319.23 and the median value of 726545 µg/l. One of the reasons of high Ca is flowing through mineralized veins related with

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Tertiary plutonism and carbonate units of thermal water in Ramsar region. The Cl content of thermal waters has an assay 16 to 62903 µg/l. The average is about 12636.7 µg/l, with an SD. of 155.06 and the median value of 8961 µg/l. Following Groundwater acts in 1991; standard drinking has Cl content less than 200 mg/l, brackish water has Cl content about 1,400– 3,000 mg/l and salty water has Cl more than 3,000 mg/l. Most of Thermal springs in this area have Cl content less than 200 mg/l.The K content of thermal water is between 6765 and 187925 µg/l. The average is about 51132.33 µg/l, with an SD. of 122.36 and a median value of 42012 µg/l. Most of thermal waters have medium K content. The Mg content of thermal water has arranged between 120886 and 893703 µg/l. The average is about 249722.4 µg/l., with an SD. Of 127.36 and the median value of 202128.The Na content of thermal water shows ranging from 35789 to 32600000 µg/l. The average is 6705330 µg/l, with an SD. Of 123.89 and the median value of 4942747 µg/l.The contents of Ca, Cl, K and Mg in thermal water are high concentration of these elements in some Thermal springs. 2.6 Fe (iron) : The Fe content of 9 Thermal springs has range from 754 to8849 µg/l. The average is 2287.33 µg/l, the SD is 138.334 and the median is 1311 µg/l. Most of them have Fe content higher than 1 mg/l; this value is the standard drinking water of Groundwater acts in 1991. To solve high Fe content in the water is to fill oxygen in to water, and related with infiltration mature water and interaction with mineralized and Alteration veins. 2.7 Mn (manganese) : The Mn content of 9 Thermal spring samples range from 37.43 to463.26 µg/l. The average is about 92 µg/l, the SD is 91.199 and the median value equals to 46.85 µg/l. 2.8 SiO2 (silica) : A total of 9 assay of thermal water show SiO2 content from 2.15 to 19 mg/l. The average is 4.6 mg/l, and a median value of 2.52 mg/l. Thermal springs have low SiO2 content in this area. 2.9 SO4 (sulfate) :The SO4 content of 9 Thermal springs has a range between 152 mg/l and 247.2 mg/l. The average is 204.13 mg/l, with an SD. of 8.06 and a median value of 216.71mg/l. The Thermal springs having high SO4 are mostly located in the spas. Cl-SO4-HCO3 triangular diagram (Giggenbach, 1991) in Figure 2, Ca-Na-K equilibrium triangular diagram and Ca-Na-Mg equilibrium triangular diagram (modified from Hen,1959; Giggenbach, 1991 and Arnorsson,S.200) in Figure 3and Figure 4 present property of thermal water in the Ramsar area. Cl-SO4-HCO3 triangular diagram shows that some of thermal water are located near the bicarbonate region such as Safarod and Absiah thermal springs and they are known as ( Peripheral Waters) due to absorobtion of deep CO2 and to the mixing with shallower water. Most of thermal water property is saline water and located near the Cl content also related with Mature water area. In Figure 3 and Figure 4 There are approximately 90% of total numbers of Thermal springs water samples show high Na content . On the basis of result from the chemical analysis of SiO2, Na, K, Ca and triangular geothermometers(Figure 5) were then calculated to estimate reservoir temperature (Fournier, 1981), (Giggenbach 1991). The estimated reservoir temperatures from the equations above are summarized in Table 1.Estimated temperature from triangular geothermometers (Giggenbach 1991), is approximately the same as the temperature obtained from quartz no stream loss , quartz maximum stream loss, where as Na-K-Ca geothermometer shows higher estimate temperature and the highest estimate temperature is Na/K and Na-K-Ca-Mg geothermometer, and triangular geothermometer is shown reservoir temperature between 100 ºc to 120 ºc .

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3. CLASSIFICATION OF THERMAL SPRING There are many criteria to classify Thermal springs such as temperature, pH, chemical composition etc. These criteria depend on purpose or object of classification. The object of these classifications is to sustainable management and development. 3.1 Temperature Classification: There are 3 types of Thermal springs classified by surface temperature as follow;The 7 data of springs in Ramsar indicated that Thermal springs (80%) are thermal springs, where as 1 Thermal springs (10%) are hyperthermal springs. 3.2 pH Classification: Thermal springs in Ramsar have1 classes on the basis of pH. These are weak acid spring . (pH = 4–6). 3.3 Usage Classification :There are 3 types of this classification: Electric power generation plant, swimming pool and Tourism, House heating and Greenhouses. There are approximately 13% of Thermal springs used in tourism purpose. The Electric power generation plant of Thermal springs in Ramsar is approximately 70%, where 17% of Thermal springs in this area use to House heating and Greenhouses. It is useful to know status of all Thermal springs, if sustainable development of geothermal are needed. 4. CONCLUSION Most of Thermal springs in Ramsar are classified in sodium chloride, some of them are calcium sulfate water. In the thermal water generally exhibits strong smell of sulfur and high SiO2 contents. The surface temperature is between 19oC – 65oC. The SiO2 geothermometer shows estimated reservoir temperature range from 86 o C – 96o C. here are two types of Thermal spring classification system; temperature and geothermal usage. On the basis of temperature, there are three classes of Thermal springs in Ramsar: 10 % of Thermal spring is hyperthermal spring (50- 99o C) and 80% show thermal spring (30-50o C). The last classification is geothermal usage. They are classified in 3 types: There are approximately 13% of Thermal springs used in tourism purpose. The Electric power generation plant of Thermal springs in Ramsar is approximately 70%, where 17% of Thermal springs in this area use to House heating and Greenhouses. Extremity , suggestion to exploration to deep( reservoir > 1000 m depth), is essential for assessment of deep reservoir potential and identifying the up flow zone. The present discharge may be used for direct heat uses viz. spa, greenhouse cultivation, food industry and tourist attraction. ACKNOWLEDGEMENT The authors’ is grateful With BPJ programming (Bashgah Pazhoheshgaran Javan), in Islamic Azad University ;Chaloos branch and Director General of Islamic Azad University ; Chaloos branch, Proof. M.Sam and Dr.J. Ghomi, for granting permission to publish the paper. REFERENCES

Ansari,M,R. Nazeri,M. Geology and Geochemistry study of Ramsar Thermal spring.2009.report of BPJ(Bashgahe Pazhooheshgaran Javan) .

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Arnorsson,S.2000.Isotopic And Chemical Techniques In Geothermal Exploration, Development and Use.

Fournier, R., O., 1981. Application of water geochemistry exploration and reservoir engineering, in Rybach, L., and Muffler, L.J.P., eds., Geothermal system,: Principle and case histories, New York John Wiley &Sons Inc., pp. 109-144.

Arnorsson, S. and Gudmundsson Bjorn Th., 2003. Geochemical monitoring of the response of geothermal Reservoirs to production load examples from Krafla Iceland. Proceedings, International Geothermal Conference, Reykjavik, Iceland.pp.30-36.

Giggenbach, W.F., 1991. Chemical techniques. In Application of geochemistry in geothermal reservoir development, (Ed) D’Amore, United Nation Institute for Training and Research, USA. Pp.119-144.

Hen, J.D., 1959. Study and Interpretation of the chemical characteristics of Natural water. Geological Survey water supply paper, 269 p...

Table 1: estimated reservoir temperature from 9 type of geothermometer

1 2 3 4 5 6 7 8 9

Qtz no Qtz Max Chalcedony α-Ciristobalite Na-K

Na-K-Ca

Na-K-Ca-Mg Mg-Li Na-Li

H1 88.744�c 91.219˚c 57.929˚c 38.66˚c <150˚c 95.318˚c >350˚c 38.347˚c 38.347˚c H2 88.868˚c 91.327˚c 58.061˚c 38.781˚c <150˚c 94.391˚c >350˚c 38.71˚c 50.304˚ H3 93.248˚c 95.14˚c 62.72˚c 43.044˚c <150˚c 95.462˚c >350˚c 39.109˚c 50.821˚c H4 92.005˚c 94.059˚c 61.396˚c 41.832˚c <150˚c 92.125˚c >350˚c 38.386˚c 48.489˚c H5 85.9˚c 88.737˚c 54.914˚c 35.809˚c 278.41˚c ` <0˚c 13.571˚c 181.85˚c H6 83.558˚c 86.7˚c 52.436˚c 33.6˚c <150˚c 94.081˚c >350˚c 55˚c 41.647˚c H7 94˚c 96˚c 63˚c 44˚c <150˚c 99.543˚c >350˚c 55˚c 41.647˚c H8 94.551˚c 96.272˚c 64.11˚c 44.03˚c <150˚c 195˚c >350˚c 47˚c 75˚c H9 91.4˚c 93.5˚c 60.7˚c 41˚c <150˚c 107˚c >350˚c 45˚c 78˚c . 1)Fournier (1977); 2) Fournier (1977); 1) Fournier (1977); 2) Fournier (1977);5) Fournier (1979); 6) Fournier& Truesdell (1973); 7) Kharaka, Y.K. and R.H. Mariner, (1989);8) Kharaka, Y.K. and R.H. Mariner, (1989) 9) Kharaka, Y.K. and R.H. Mariner, (1989).

Figure1: Geological map of Ramsar area.

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Figure 2 : Cl-SO4-HCO3 triangular diagram of Figure 3 : Ca-Na-K diagram of thermal spring in Ramsar thermal spring in Ramsar

Figure 4 : Ca-Na-Mg diagram of thermal spring in Ramsar Figure 5 :Na/1000-K/100-√Mg diagram of

thermal spring in Ramsar

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Speciation of Cr (III) and Cr (VI) in Water Sample by Spectrophotometry with Cloud Point Extraction

M.Masrournia *1, A.Nezhadali 2,B.Taghezadeh-Darban3 , Zahra Ahmadabaddi1 , Habib Mollaei1

1Department of chemistry, Faculty of science,Islamic Azad University of Mashad, Mashad, Iran

2Department of Chemistry, Payame Noor University of Mashad, Mashad, Iran

3Waterr and Wastwater organization, Mashad, khorasan Razavi,Iran

Abstract The use of CPE techniques for metal speciation has become more important ..A study has been carried out to determination of Cr(VI) and Cr(III) in water sample after cloud point extraction. The method is based complexation of Cr (VI) with 1,5-Diphenylcarbazid,Cr(II) is convert to Cr(VI) by reduction agent and forms complexationthen then in the optimum condition is measured with specterophotometric method in 540 nm. The cloud point extraction was used by surfactant of Triton-x-114 for preconcentration and determination of Cr(VI).The determination of Cr(III) in the sample was achieved by absorbance difference total cromium and Cr(VI).The effective parrameter such as ,pH solution ,organic solvent, surfactant concentration, ligand concentration, extraction time temperature were investigated and optimized. Under the optimum condition the enrichment factor obtained 10.The calibration curve was linear over the range 2-200 ng m l -1 with relative standard deviation(RSD)0.3%(n=10 at 100 ng m l -1). The interference effects of some cations were studied. The performance of the proposed technique was evaluated for the determination of Cr (VI) and Cr (III) in the water sample (tap water and waste water). Introduction Chromium is one of the most abundant elements on Earth. The amount of chromium in the environment has gradually been increased predominantly by industrial activities especially from tanneries, mines and incinerators [1]. Chromium exists in Cr(III) and Cr(VI) oxidation states in aqueous solutions [2], [3] and [4]. The properties of these species are different [1]. Trivalent chromium, the main chemical form found in foods, is essential for maintaining normal glucose metabolism [4] and [5]. Cr (VI) oxidation state is detrimental to health as it may be involved in the pathogenesis of some diseases like liver, kidney, lung and gastrointestinal cancers. Industrial processes such as plating, tanning, paint production, pigment production and metallurgy involve the use of Cr(VI) compounds and are therefore the most frequent source of hexavalent chromium [5] and [6]. The importance of chromium speciation is governed by the fact that the toxicity and reactivity depend on the chemical form or oxidation state of chromium [7-9]. Separation and preconcentration based on cloud point extraction (CPE) are becoming an important and practical application of surfactants in analytical chemistry. The technique is based on the property of most non-ionic surfactants in aqueous solutions to form micelles and become turbid when heated to a temperature known as cloud point temperature. Above cloud point temperature, the micellar solution separates into a surfactant-rich phase of a small volume and a diluted aqueous phase, in which the surfactant concentration is close to the critical micellar concentration (CMC). Any analyte solubilized in the hydrophobic core of the

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micelles will separate and become concentrated in the small volume of the surfactant-rich phase. The aim of the present work was to apply CPE as a separation and preconcentration step combined with spectrophotometry for the speciation of chromium. The experimental parameters affecting the CPE efficiency were investigated in detail. The proposed method has been applied to the speciation of chromium in tap and lake water samples with satisfactory results Experimental Instrumentation A UV –Vis spectrophotometer-6405 (JENWAY) was used. The pH values were measured with a pH meter Sartorius pp-15 Model glass-electrode. A thermostated bath maintained at the desired temperatures was used for the cloud point experiments. An 80-2 centrifuge (Changzhou Guohua Electric Appliance CO. LTD. , PR China) was used to accelerate the phase separation. Standard solution and reagents All chemicals used were of analytical grade .Stock solution (1.000 g L−1) of Cr (III) was prepared by dissolving of CrCl3·6H2O in 0.1 mol L−1 hydrochloric acid. Stock solutions (1.000 g L−1) of Cr (VI) were prepared by dissolving of K2Cr2O7 in 0.1mol L−1 nitric acid. The non-ionic surfactant Triton X-114 was obtained from Sigma (St. Louis, MO, USA) and was used without further purification. A 1.0 × 10−2 mol L−1 solution of 1, 5-Diphenylcarbazid was prepared by dissolving appropriate amounts of this reagent in absolute methanol from the commercially available product. Doubly distilled water was used throughout the entire experiment. The pipettes and vessels used were kept in 10% nitric acid for at least 24 h and subsequently washed four times with doubly distilled water. Cloud point extraction procedure For CPE, 10 mL aliquots of a solution containing the Cr (VI) buffered at a suitable pH, Triton X-114 and1, and 5-Diphenylcarbazid solution were kept in the thermostatic bath maintained at 60 °C for 20 min. The solution separated into two phases, and the surfactant-rich phase could settle through the aqueous phase. Phase separation was accelerated by centrifuging the solution at 4000 rpm for 10min. After cooling in an ice-bath, the surfactant-rich phase became viscous and was retained at the bottom of the tube. The aqueous phases can readily be discarded simply by inverting the tubes. To decrease the viscosity of the surfactant-rich phase and allow its pipetting, 1 ml of 0.1 mol L−1 HNO3 was added to it and diluted with methanol to 5 ml then determine chromium at 540 nm. Calibration was performed against aqueous standards submitted to CPE procedure. A blank submitted to the same procedure was measured parallel to the samples and calibration solutions. Oxidation of Cr(III) to Cr(VI) has been performed After oxidation of Cr(III) to Cr(VI) by using H2O2 in basic media, the method was applied to the determination of Cr(VI) Sample analysis Tap water samples were taken from our laboratory and region located in Korasan Razave were collected in pre-washed polyethylene bottles and then the samples were filtered through a Millipore cellulose membrane filter with 0.45 µm of pore size and analysed as soon as possible after sampling. The water samples must not be acidified before storage, because this

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would change the chemical species. The analysis of chromium species in water samples was made as described above. Total chromium in natural water samples was determined as chromium (VI) after oxidation of Cr (III) to Cr (VI) by using H2O2. The concentration of Cr (III) was calculated by substracting the concentration of Cr (VI) from total chromium concentration. Results and discussion Effect of pH on CPE of Cr (III) and Cr (VI) The formation of hydrophobic metal complex and its chemical stability are the two important factors influencing CPE efficiency. The pH plays a unique role on the metal complex formation and subsequent extraction. The effect of pH on the CPE efficiency of Cr (VI) was studied and the results are shown that extraction was quantitative (recovery > 95%) for Cr (VI) in the pH range 5.0–7.0. Effect of 1, 5-Diphenylcarbazid concentration A 10 mL solution containing 100 ng of Cr (VI) in 1.0 g L−1 Triton X-114, at a medium buffer of pH 5-7 containing various amounts of 1, 5-Diphenylcarbazid was subjected to the CPE process. The extraction recovery for Cr (VI) increased up to a 1, 5-Diphenylcarbazid concentration of 7.5 × 10−4 mol L−1 and reaches near 100%. A 1, 5-Diphenylcarbazid concentration of 1.0 × 10−3 mol L−1 was chosen to account for other extractable species that might potentially interference with the extraction of Cr (VI). Effect of Triton X-114 concentration A successful CPE would be that maximizes the enrichment factor through minimizing the phase volume ratio. The variation in extraction efficiency of chromium within the Triton X-114 concentration range of 0.1–2.0 g L−1 was examined. Quantitative extraction was observed when Triton X-114 concentration above 0.9 g L−1. So a concentration of 1.0 g L−1 was chosen as the optimum surfactant concentration in order to achieve the highest possible enrichment factor. Effects of equilibration temperature and time It was desirable to employ the shortest equilibration time and the lowest possible equilibration temperature as a compromise between completion of extraction and efficient separation of phases. The dependence of extraction efficiency upon equilibration temperature and time was studied with a range of 25–80°C and 5–30 min, respectively. The results showed that an equilibration temperature of 60 °C and a time of 10 min were adequate to achieve quantitative extraction. Interferences The effect of various interfering ions found in water samples, on the determination of Cr (VI) was studied. Cations that may react with 1, 5-Diphenylcarbazid and are extracted to the micelle phase were studied. The tolerance limits of the coexisting ions, defined as the largest amount making the recovery of Cr (VI) less than 90%, are given in Table 1. It can be seen that the major cations in the water samples have no obvious influence on the extraction of Cr (VI) under the selected conditions.

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Characteristics of the method Under the optimal experimental conditions, the calibration curve for Cr (VI) is linear up to 200 ng mL−1 with a correlation coefficient (r) of 0.9990. The relative standard deviation (R.S.D.) for 10 samples of 100 ng mL−1 of Cr (VI) subjected to the CPE procedure is 0.3%. The detection limit (LOD) of this method, calculated as three times the standard deviation of the blank signals, is 1.5 ng ml−1. The enrichment factor, calculated as the ratio of the absorbance of the preconcentrated sample to that obtained without preconcentration, is 10. Sample analysis The proposed method has been applied to the determination of Cr (III) and Cr (VI) in tap and lake water samples collected in Mashhad. In addition, the recovery experiments of different amounts of Cr (III) and Cr (VI) were carried out, and the results are shown in Table 2. The results indicated that the recoveries were reasonable for trace analysis, ranging from 98 to 101%. Conclusion The feasibility of chromium speciation in water has been demonstrated based on cloud point extraction of Cr (VI) with1, 5-Diphenylcarbazid in the presence of the surfactant Triton X-114 and sequential determination by spectrophotometry. The developed method is definitely simple, reproducible, and highly sensitive, because of the distinct and advantageous features of CPE (in situ and single-step extraction). The method has been successfully applied to the speciation of chromium in tap and lake water samples, and the precision and accuracy of the method are satisfactory. The method may also be used for the speciation of chromium in various matrices other than water. References

[1] A. Manova, S. Humenikova, M. Strelec and E. Beinrohr, Determination of chromium(VI) and total chromium in water by in-electrode coulometric titration in a porous glassy carbon electrode, Microchim. Acta 159 (2007), pp. 41–47.

[2] S. Yalçin and R. Apak, Chromium (III, VI) speciation analysis with preconcentration on a maleic acid-functionalized XAD sorbent, Anal. Chim. Acta 505 (2004), pp. 25–35.

[3] M. Ghaedi, E. Asadpour and A. Vafaie, Sensitized spectrophotometric determination of Cr(III) ion for speciation of chromium ion in surfactant media using alpha-benzoin oxime, Spectrochim. Acta 63A (2006), pp. 182–188.

[4] N. Rajesh, B.G. Mishra, P.K. Pareek, Solid phase extraction of chromium(VI) from aqueous solutions by adsorption of its diphenylcarbazide complex on a mixed bed adsorbent (Acid Activated Montmorillonite -Silica gel) column, Spectrochim. Acta Part A, in press.

[5] M.J. Marqués, A. Salvador, A. Morales-Rubio and M. de la Guardia, Chromium speciation in liquid matrices: a survey of the literature, Fresen. J. Anal. Chem. 367 (2000), pp. 601–613.

[6] B. Preetha and T. Viruthagiri, Bioaccurnulation of chromium (VI), copper(II) and nickel(II) ions by growing Rhizopus arrhizus, Biochem. Eng. J. 34 (2) (2007), pp. 131–135.

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[7] S. Pramanik, S. Dey and P. Chattopadhyay, A new chelating resin containing azophenol-carboxylate functionality: synthesis, characterization and application to chromium speciation in wastewater, Anal. Chim. Acta 584 (2007), pp. 469–476.

[8] F. Shemirani and M. Rajabi, Preconcentration of chromium (III) and speciation of chromium by electrothermal atomic absorption spectrometry using cellulose adsorbent, Fresen. J. Anal. Chem. 371 (2001), pp. 1037–1040.

[9] L. Shen, J.L. Xia, H. He, Z.Y. Nie and G.Z. Qiu, Biosorption mechanism of Cr(VI) onto cells of Synechococcus sp, J. Cent. South Univ. Technol. 14 (2) (2007), pp. 157–162.

Table1 Tolerance limits of coexisting ions Cr (VI): 100 ng mL−1.

CPE conditions: 1 × 10−3 mol L−11, 5-Diphenylcarbazid , 1.0 g L−1 Triton X-114, pH 5.0-7.0.

Table 2 Determination of chromium species in natural water samples a Mean of five determinations. b Calculated value.

Coexisting ions Foreign ion to analyte ratio

K+, Na+ 1000

Ca2+, Mg2+, Ba2+, 500

Cu2+, Mn2+, Zn2+, Cd2+, Ni2+, Pb2+

10

Al3+, Fe3+, Cr(VI) 50

Samples Added (ng ml−1) Found a (ng ml−1) Recovery (%)

Cr(III)

Cr(VI) Cr(III) Cr(VI) b Total Cr(III)

Cr(VI)

Tap water 0 0 3.3± 0.1 2.4 ± 0.1 5.8 ± 0.1 – –

2.0 2.0 5.2 ± 0.1 4.4 ± 0.1 9.6 ± 0.2 98 100

5.0 5.0 8.4 ± 0.2 7.3 ± 0.2 14.7± 0.3 101 98

Lake water 0 0 5.5 ± 0.2 4.1 ± 0.1 9.7 ± 0.3 – –

5.0 5.0 10.5± 0.3 9.0 ± 0.1 19.5± 0.4 100 98

10.0 10.0 15.3 ± 0.3 14.3 ± 0.3 29.6 ± 0.5 99 101

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Numerical analysis of hydraulic fracturing process in wellbores; A three dimensional mixed mode study

M.R. Ayatollahi*, M.R.M. Aliha, M.H. Pourkavian

Corresponding author: Fatigue and Fracture Lab., Department of Mechanical Engineering, Iran University of Science and Technology, Narmak, Tehran, 16846, Iran

E-mail address: m.ayat@ iust.ac.ir Abstract The hydraulic fracturing operation is a suitable method for stimulating and increasing the productivity of oil and gas wells. Since the hydraulic fracturing is essentially a process of crack growth in the wellbores and the reservoirs formations, it is preferred to investigate this method using the concepts of rock fracture mechanics. In practice, because of heterogeneity and anisotropy of rock layers and formations and also the magnitude and the direction of in situ stresses, the created hydraulic fractures may grow under mixed mode tensile-shear loading. Thus in this paper, the stress intensity factors of a semi-circular crack in the wall of a vertical wellbore were determined by means of various 3D finite element analyses in the ABAQUS code. In the analyzed models, the influence of the initial crack direction relative to the in situ principal stresses on the stress intensity factors KI and KII were investigated. It was shown that by changing the angle between the crack plane and the maximum horizontal principal stress (σ2), the mode I component decreases and the corresponding mode II stress intensity factor (KII) increases. However, the effect of KI was more pronounced than KII in deformation of crack during the hydraulic fracturing process. A design mixed mode fracture curve was also presented for theoretical estimation of the minimum required pumping pressure for any mixed mode loading situation in the hydraulic fracturing. 1. Introduction During the past decades, many research studies have been conducted in the field of hydraulic fracturing [1]. This technique is basically used for increasing the productivity of oil and gas wellbores. In this method an artificial fracture is induced in the wall of well by applying the fluid pressure which is pumped by especial devices [2]. The created fractures are then extended into targeted rock formations and hence increase the productivity of wells [3]. Fig. 1 shows a schematic representation of this process [4]. Since the hydraulic fracturing is essentially a process of crack growth in the wellbores and the reservoirs formations, it is essential to investigate this method using concepts of rock fracture mechanics. In this discipline, the state of stress/strain field for any types of crack deformations including opening (mode I), in-plane sliding (mode II) and out-of-plane sliding (mode III) is defined by the stress intensity factors. In most of the previous analytical and theoretical fracture mechanics models it is assumed that the initiation and then growth of hydraulic fracture is occurred under pure tension or pure mode I condition [5]. However, because of heterogeneity and anisotropy of rock layers and formations, the created hydraulic fractures in practice may grow under mixed mode loading. In these cases, the influence of other fracture modes including in and out of plane sliding can affect the fracture process in addition to the crack opening mode. Meanwhile, the hydraulic fractures in inclined wells generally initiate and propagate under mixed mode loading. Therefore, for a more accurate analysis of hydraulic

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fracturing, it is important to investigate this procedure using mixed mode fracture models [6]. For understanding the mixed mode crack growth behavior during the hydraulic fracture and for controlling the fracture path, the stress state in front of the growing crack should be studied. The stress intensity factors are the main parameters for describing the crack growth behavior during the hydraulic fracturing process. The magnitude and the direction of in situ stresses at great depths can affect strongly the fracture behavior of rock masses around the wellbores. Fig. 2 shows three principal stresses that are applied to a rock element at a great depth. The vertical principal stress component (σ 1) is induced from the weight of upper rock masses and the two horizontal stresses of σ2 and σ3 are the maximum and minimum horizontal principal stresses, respectively induced from the tectonic plate and the earth layers reactions [7]. In this paper, the fracture parameters of a semi-circular crack induced due to perforation in the wall of a vertical oil well are determined numerically by means of various 3D finite element analyses. In the analyzed models, the influence of initial crack orientation with respect to the direction of horizontal principal stresses is investigated. It is shown that for many of the considered situations, the hydraulic fractures grow in a mixed mode manner and hence the sliding mode stress intensity factor also affects the fracture behavior in addition to the mode I stress intensity factor. 2. Numerical modeling of hydraulic fracturing process Fig. 3 shows the 3D geometry and loading configuration of a reservoir rock formation having a vertical well which is subjected to three in–situ stresses of σ1, σ2 and σ3 and an internal pressure of Pf. A semi circular crack perforated in the wall of well and perpendicular to the borehole is also considered that generally makes an angle σ with respect to the direction of σ2

as shown in Fig. 4. For analyzing the fracture behavior of the cracked wellbore under the illustrated loading condition a 3D finite element model of the well and rock formation was created in the ABAQUS finite element code. A cube of 2m length was considered as the formation rock and, as shown in Fig. 5 a cylindrical hole with diameter of 20 cm was created in the middle of cube to simulate the well. Also the radius of the semi circular crack perforated in the wall of well was chosen equal to 4 cm. The elastic material properties of a typical reservoir formation rock as E = 10 GPa and ν = 0.25 reported by Ingraffea et al. [8] were also considered in the finite element models. A total number of 11000 solid brick elements were used for creating the finite element model. A large number of fine and singular elements were also used in the first ring of crack front line for producing the square root singularity of stress/strain field. Fig. 5 shows the finite element mesh pattern for the well and a zoomed view of the crack region. The stress intensity factors (KI and KII) are functions of the applied in situ stresses and the crack geometry as well and can be written as:

III,),,,,,( 321 == iaPfK fi γσσσ (1)

where, a is the radius of the semi circular crack. The following stresses given by Ingraffea et al. [8] were also applied to the model: σ 1 = 80 MPa, σ 2 = 70 MPa, σ 3 = 60 MPa and Pf = 60 MPa. A J-integral based method built in ABAQUS was used for obtaining the stress intensity factors KI and KII directly from software.

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3. Results and discussion The results obtained for mode I and mode II stress intensity factors (KI and KII) from the finite element analysis have been presented in Fig. 6 for different angles of σ. The normalizing parameter (KIc) in this figure is the pure mode I fracture toughness which assumes to be a constant material property for any cracked material. For normalizing the obtained stress intensity factors, the reported value of KIc = 5 MPa m0.5 for a coal reservoir [8] was used. It is seen from Fig. 6, that when the direction of crack is along the direction of maximum horizontal principal stress (i.e. when the angle σ is zero) the crack is subjected to pure mode I loading (KII = 0). By increasing the angle σ from zero, mode II component also appears in the crack deformation. Indeed for non zero crack angles σ, the perforated crack in the wall of wellbore experience a combination of opening-sliding deformation and thus both mode I and mode II components become important in crack growth behavior of the hydraulic fracturing process. However, it is seen from Fig. 6 that the effect of KI component is more pronounced than KII in the given case. Also by increasing the crack angle σ, KI decreases and conversely KII increase and at a special crack angle KI becomes zero while KII is non zero. This angle corresponds to pure mode II (pure shear) loading conditions. For the analyzed model, this condition is achieved typically at an angle σ = 30o. After this angle, the KI component becomes negative and hence the crack faces tend to compress to each other. Thus, for these conditions, the required pumping pressure for opening the crack flanks and growing the hydraulic fracture is increased noticeably. Since the hydraulic fracturing is in general a process of mixed mode crack growth, for a theoretical evaluation of this process the mixed mode fracture criteria should be used. For example, a theoretical mixed mode fracture curve shown in Fig. 7 has been presented by Erdogan and Sih [9] based on a well known maximum tangential stress criterion. This fracture curve can be used for estimating the required minimum pumping pressure in the hydraulic fracturing process under any combinations of tensile-shear loads including pure mode I and pure mode II and mixed mode I/II conditions. For any mode mixities, by increasing the level of applied pumping pressure, the values of KI and KII increase linearly and the hydraulic fracture starts to grow when the corresponding values of the mode I and mode II stress intensity factors reach the design curve. Therefore, by estimating the critical stress intensity factors, the corresponding required pumping pressure can be evaluated for any loading conditions. This pumping pressure, as seen from Fig. 7, also depends on fracture toughness of the rock formations in front of the perforated crack in the wall of the wellbore. 4. Conclusions - Crack growth in hydraulic fracturing process can be occurred generally in mixed mode tensile-shear manner. - The mixed mode stress intensity factors (KI and KII) for a vertical well having a semi circular crack in the wall of wellbore subjected to in situ stresses and internal pumping pressure were computed numerically using 3D finite element analyses. - By changing the orientation of crack with respect to the direction of the maximum horizontal principal stress (�2), different combinations of mode I and mode II were determined for the investigated model. However the influence of tensile mode was more pronounced than the shear mode.

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- For performing an optimum hydraulic fracturing process under mixed mode I/II conditions, the theoretical fracture criterion scan be employed to estimate the minimum required pumping pressure. 5. References

[1]. Wilkinson J.R., Teletzke G.F. and King K.C., (2006), “Opportunities and Challenges for Enhanced Recovery in Middle East” SPE Monograph, 22:15-20.

[2]. Economides M., (2004),“Evaluation of Impacts to Underground Sources of Drinking Water by Hydraulic Fracturing of Coalbed Methane Reservoirs”, Department of Energy, pp 2-24.

[3]. Bareer R.D., Fisher M.K. and Woodroof R.A., (2002), “A practical guide to hydraulic fracturing diagnostic technologies”, SPE Annual Technical Conference and Exhibition, Texas, 10-15.

[4]. Cornet F.H., Doan M.L. and Fontbonne F., (2003), “Electrical imaging and hydraulic testing for a complete stress determination”, International Journal of Rock Mechanics & Mining Sciences, 40: 2-6.

[5]. Thompson P.M. and Chandler N.A., (2004), “In situ rock stress determinations in deep boreholes at the Underground Research Laboratory”, International Journal of Rock Mechanics & Mining Sciences, 41:1-5.

[6]. Queipo V., Verde J., Canelo J and Pintos S., (2002), “Efficient global optimization for hydraulic fracturing treatment design”, Journal of Petroleum Science and Engineering, 45:1-2.

[7]. Sneddon I.N., (1946), “The distribution of stress in the neighborhood of a crack in an elastic solid”, Proceedings of the Royal Society of London, pp 229-260.

[8]. Ingraffea A.R., Saouma V., (1985), “Numerical modeling of discrete crack propagation in reinforced and plain concrete”, Netherlands: Martinus Nijhoff Publishers, pp 171-225.

[9]. Erdogan, F., Sih, G.C., (1963), “On the crack extension in plates under plane loading and transverse shear”, Journal of Basic Engineering, Trans ASME 85: 519-25.

Frac pumper

Sand truck

Blender truckFracturing fluid and proppant

Fluid tank

Producing formation

Created fracture

Proppantingredients

Fig. 1: Schematic representation of hydraulic fracturing process in wellbores [4].

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Fig. 2: Principal in situ stresses at great depth applied to a rock element [7].

1σ

2σ

3σ

fP

1σ

3σ

2σ

Fig.3: Geometry and loading configuration of reservoir formation containing a cracked vertical wellbore.

Fig. 4: Inclination angle (�) of a vertical semicircular crack perforated in the wall of vertical well relative to the direction of maximum horizontal principal stress

Crack tip regionCrack tip region

Fig. 5: Finite element mesh pattern created for modeling the reservoir formation, vertical well and a semi circular crack.

0 10 20 30 40 500.00

0.02

0.04

0.06

0.08

0.10

0.12

0.14

0.16

0.18

0.20

CKK

ΙΙΙ

)degree(γ

0 10 20 30 40 50

-0.4

-0.2

0.0

0.2

0.4

0.6

CKK

ΙΙ

)degree(γ

Fig 6: Variations of mode I and mode II stress intensity factors with crack angle σ for the analyzed crack in the wall of wellbore.

1σ

3σ

2σ

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Non propagating hydraulic fracture zone

Mixed mode fracture design curve

Propagating hydraulic fracture zone

Non propagating hydraulic fracture zone

Mixed mode fracture design curve

Propagating hydraulic fracture zone

Fig. 7: Mixed mode fracture design curve for estimating the required pumping pressure during a hydraulic fracturing process.

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On crack growth path of rock materials subjected to tensile loading

M.R. Ayatollahi *, M.R.M. Aliha , M. Rezaei

Corresponding author: Fatigue and Fracture Lab., Department of Mechanical Engineering, Iran University of Science and Technology, Narmak, Tehran, 16846, Iran

E-mail address: [email protected] Abstract Underground mining and tunneling have been developed extensively in many geological related applications like underground railways, gas and oil wellbores and deep tunnel mining. Since the tunneling and excavation are based on a process of crack growth in the rock masses, the investigation of crack growth behavior and controlling its propagation path is an important task for designing and constructing the underground structures. In this paper, the stability of crack growth path under tensile mode of loading in a rock sample is studied both experimentally and theoretically using fracture mechanics approach. A series of fracture experiments were conducted on the Iranian Harsin white marble using the double cantilever beam (DCB) and semi circular bend (SCB) configurations. While the path of crack growth in the SCB specimens was stable and self similar, the crack curving was observed for the DCB specimens. The directions of crack growth initiation for the DCB specimen did not comply with the predictions of the available classical fracture criteria. However, it is shown that a generalized fracture criterion which takes into account the effects of both specimen geometry and material type can predict very well the fracture behavior of the tested rock material. It is shown that the crack curving in the tested DCB specimens made of coarse grain Harsin marble is mainly due to the noticeable positive T-stresses that exist in the DCB specimens and the relatively large size of fracture process zone in this material. 1. Introduction Nowadays, underground mining and tunneling have been developed extensively in many geological related applications like underground railways, gas and oil wellbores and deep tunnel mining. In such applications, the higher safety and stability of the constructed tunnels, the faster speed of excavation and rock cutting. Increasing the productivity of oil and gas wells is also one of the main designing parameters for the geology and mining engineers. Since the excavation of rock masses is basically a process of crack growth in the rocks, the investigation of crack growth behavior and controlling its propagation path, is an important task for designing and constructing the underground structures. The existence of initial cracks, flaws, joints, beddings and weak planes and inherent discontinuities is one of the main natural characteristics of rock masses. Hence, for a more precise analysis and design of the rock structures, the influence of cracks and flaws should be studied. The linear elastic fracture mechanics (LEFM) can provide a suitable framework to study the crack growth behavior in cracked rock masses. LEFM deals with various experimental methods and theoretical fracture criteria for evaluating the onset of crack growth and the direction of fracture path. In this paper, the stability of crack growth path under tensile mode of loading in a rock sample (Iranian Harsin white marble) is studied both experimentally and theoretically using two test samples namely: the double cantilever beam (DCB) and the semi circular bend (SCB) configurations. Also, the parameters affecting the initiation of fracture and the path of the crack extension in the tested rock, is investigated theoretically. Using a generalized fracture

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criterion, it is shown that the stability of mode I crack growth for the tested rock material, is controlled by the sign and the magnitude of T-stress and the size of fracture process zone as well. 2. Theoretical aspects Crack growth in rocks or other geo-materials often occurs under crack-opening deformation (known as mode I) and in a brittle fracture manner. Since the geometry and loading conditions in mode I deformation are symmetric with respect to the crack plane, it is usually expected that the mode I crack growth would be self-similar i.e. along the direction of original crack. This phenomenon is in agreement with the predictions of the classical fracture criteria for mode I loading [1-3]. These criteria suggest that the angle of fracture initiation in pure mode I loading, is always zero and the path of crack growth is stable and along the initial crack line. However, a review of literature shows that some of the mode I fracture paths observed for various engineering materials like rocks are not along the original crack line. Indeed, the mode I fracture may grow in some cases along a curvilinear path. Thus, some researchers have attempted to investigate the stability of crack growth path under mode I loading. For example Cottrell and Rice [4], used a well known maximum tangential stress (MTS) criterion for investigating the mode I crack curving problem. The elastic tangential stress for mode I loading condition can be written as an infinite series expansion [5]:

)(sin2

cos21 2

123

I rOTKr

++= θθπ

σθθ (1)

where r and θ are the polar co-ordinates, KI is the mode I stress intensity factor and T is a constant and nonsingular stress term usually called the T-stress. The higher order terms O(r1/2) are negligible near the crack tip. According to Cottrell and Rice [4], the sign of T-stress is the main controlling parameter for the stability of crack growth under mode I loading. Based on their study, the path of crack growth for those mode I specimens having a negative T-stress is stable and along the original crack line and conversely for those specimens that the sign of T-stress is positive, the crack curving would be occurred. Although their theory could provide good predictions for the stability of crack growth in some specimens, their criterion failed for some other mode I experiments. Then Ayatollahi and his co-workers [6], presented a more accurate criterion for justifying the mode I crack growth behavior. Based on Ayatollahi et al. [6], the direction of fracture initiation angle in mode I depends not only on the sign of T-stress but also on the magnitude of T-stress and the material properties as well. Brittle fracture occurs when the maximum tangential stress (σθθ) at a critical distance rc in front of the crack tip, reaches a critical value (σθθc). The required conditions for satisfying the above statement are:

0,0 2

2p

θσ

θσ θθθθ

∂

∂=

∂∂ (2)

Consequently Ayatollahi et al. [6], showed that the direction of fracture initiation angle is zero if the value of B.� < 0.375. For B.� > 0.375, the direction of fracture initiation (θm) is calculated from:

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⎥⎥⎦

⎤

⎢⎢⎣

⎡+⎟

⎠⎞

⎜⎝⎛+±= −

21

323

323cos2

21

ααθ

BBm (3)

where B is the biaxiality ratio and α is a parameter related to the size of critical distance (rc). These parameters are written as:

cc r

KTB

ar

KaTB πααπ 2.2,

II=⇒== (4)

For investigating the validity of the mentioned criteria for the stability of mode I crack in rocks, a series of fracture specimens were tested using a sample rock material and by means of two different mode I geometries. In the next section, the experimental results are presented. 3. Fracture experiments on Harsin marble A schematic representation of the test specimens used for mode I fracture experiments are shown in Fig. 1. These specimens are: the semi circular specimen containing an edge crack and subjected to three-point bend loading (SCB) specimen and the double cantilever beam (DCB) specimen subjected to tensile pin loading. For conducting the fracture experiments, several SCB and DCB specimens were manufactured from an Iranian white marble rock with coarse grains (Harsin marble). The thickness (t) of both test samples was approximately 20 mm. The crack length (a) was also considered as a variable in both SCB and DCB specimens. The specimens were then loaded by means of suitable fixtures using a ball screw testing machine until the final fracture. It was observed from the experiments that, the fracture paths of all the SCB specimens were along the original crack line but the fracture paths for the tested DCB specimens were deviated from the crack line. The fracture paths for some of the broken SCB and DCB specimens are shown in Fig. 2. 4. Results and discussion For investigating the crack growth stability of the tested rock samples, based on the fracture criteria [4,6] mentioned in the previous section, the value of T-stress (or B) should be known. The fracture parameters of KI and T in both DCB and SCB specimens at the onset of fracture were calculated by means of the finite element code ABAQUS and using the fracture load obtained for each specimen. The value of rc in rock materials is usually estimated by the size of fracture process zone in front of the crack tip. Schmidt [7] has proposed the following relation for evaluating the size of fracture process zone (FPZ) in rock materials under mode I loading:

2

21)(FPZofsize ⎟⎟

⎠

⎞⎜⎜⎝

⎛=

t

Icc

Krσπ

(5)

where KIc and σt are the pure mode I fracture toughness and the tensile strength of rock, respectively. Using the ISRM suggested methods [8,9], the values of KIc and σt was obtained as 1.50 MPa m0.5 and 6.01 MPa from experiments conducted on appropriate test specimens. By replacing the obtained values of KIc and σt into Eq. (5), the process zone size rc was found about 9.91 mm. it should be noted that the size of rc in most of rock materials is considerably greater than the size of rc for many other engineering materials like metals, polymers and ceramics. Then by using the corresponding values of B.α for any test samples, the direction of fracture initiation angle can be determined theoretically by the maximum tangential stress

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criterion suggested by Ayatollahi et al. [6]. The obtained test results including the fracture angles experimentally measured from the broken samples and together with the predicted fracture angles are presented in Table 1 for both SCB and DCB specimens tested with different geometry and loading conditions. It is seen from this Table that the T-stress in all of the tested DCB specimens is noticeably positive and the corresponding B.α values are greater than 0.375. Hence, according to both criteria i.e. Cottrell and Rice [4] and also Ayatollahi et al. [6], the crack curving should occur. These predictions are in agreement with the fracture pattern observed from the broken samples (see Fig. 2). However, according to Table 1 while the T-stress for some of the tested SCB specimens was positive, the crack growth paths for all of the tested SCB specimens were stable and along the original crack line (i.e. θm was equal to zero). This result is not consistent with the theory suggested by Cottrell and Rice [4]. But the criterion suggested by Ayatollahi et al. [6] was in agreement with the fracture path observed for the SCB specimens as well. According to Ayatollahi et al. [6] the crack initiation angle for all of the tested SCB specimens would be zero because the corresponding values of B.α for any SCB specimens studied in this research were less than 0.375. Consequently, the SCB specimens should have stable crack growth path when they are subjected to pure mode I loading. Therefore, the generalized criterion suggested in [6] which takes into account the effects of magnitude and sign of T-stress and also the type of material (which was related to the size of fracture process zone) can provide more reliable estimates for crack growth stability in mode I cracks in rock masses. 5. Conclusions - Crack growth stability in mode I cracks were studied both experimentally and

theoretically for a rock material using DCB and SCB specimens. - While the path of crack growth path in the SCB specimens were stable and along the

original crack line, crack curving was observed for the DCB specimens. - The very high positive T-stress that exists in the DCB specimen and the relatively large

size of fracture process zone in the tested marble rock were the main reasons for the crack growth curving in the DCB specimen.

6. References

[1]. Erdogan, F., Sih, G.C., (1963), “On the crack extension in plates under plane loading and transverse shear”, Journal of Basic Engineering, Trans ASME 85: 519-25.

[2]. Sih, G.C., (1974), “Strain-energy-density factor applied to mixed mode crack problems”, International Journal of Fracture 10: 305-21.

[3]. Hussain, M.A., Pu, S.L., Underwood J., (1974), “Strain energy release rate for a crack under combined mode I and Mode II. Fracture Analysis”, ASTM STP 560. American Society for Testing and Materials, Philadelphia: 2-28.

[4]. Cotterell B. and Rice J.R., (1980), "Slightly curved or kinked cracks”, International Journal of Fracture 16: 155-169.

[5]. Williams, M.L., (1957), “On the stress distribution at the base of a stationary crack’, Journal of Applied Mechanics 24: 109-14.

[6]. Ayatollahi, M.R., Pavier, M.J. and Smith, D.J., (2002), "Mode I cracks subjected to large T-stresses”, International Journal of Fracture 117: 159–174.

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[7]. Schmidt, R.A., (1980), “A microcrack model and its significance to hydraulic fracturing and fracture toughness testing”, Proc US symposium on rock mechanics 21:581-590.

[8]. ISRM, International Society of Rock Mechanics, Commission on Standardization of Laboratory and Field Tests, Suggested methods for determining tensile strength of rock materials, (1978), International Journal of Rock Mechanics & Mining Sciences, Geomechanics Abstract 15:99-103.

[9]. ISRM, Suggested methods for determining mode I fracture toughness using cracked chevron notched Brazilian disk (CCNBD) specimens, R. J. Fowell, (1995), International Journal of Rock Mechanics and Mining Science, Geomechanics Abstract: 32, 57

Table 1: Experimental and theoretical results obtained for the direction of fracture initiation angle in the tested rock samples.

specimens

experimental fracture angle (Deg)

T- stress )(MPa αB

theoretical fracture angle (Deg)

SCB

=Ra 0.45 =R

S 0.50 0 -2.0750 -0.3982 0 0 -2.3180 -0.3982 0

=Ra 0.50 =R

S 0.50 0 -1.0277 -0.1554 0 5 -1.3086 -0.1554 0

=Ra 0.66 =R

S 0.60 0 0.3249 0.0659 0 10 0.5796 0.0659 0

DCB

=wa 0.20 60 6.1099 1.6509 79.98

55 6.7400 1.6515 79.98

=wa 0.30 70 7.7866 1.8258 81.02

59 9.0032 1.8259 81.02

=wa 0.70 72 8.3901 2.1228 82.36

70 9.0026 2.1229 82.36

DCB

SCB

Fig. 1: Geometry and loading conditions of SCB and DCB specimens subjected to mode I loading (dimensions: mm).

Fig. 2: fracture paths observed for some of the tested SCB and DCB specimens tested with Harsin marble.

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Seismicity and Seismotectonic in the Strait of Hormuz

Mehdi Rastgoo*, Sayyed Mahmood Azhari, Mohammad Reza Gheitanchi

Corresponding author: Institute of Geophysics, University of Tehran, Iran, Po. 1435944411

[email protected] (M. Rastgoo)*, [email protected] (S. M. Azhari), [email protected] (M. R. Gheitanchi)

Abstract The Iranian plateau lies along a broad zone of deformation that forms part of Alpine-Himalayan orogenic belt. It located between Arabian plate in southwest and Eurasian plate in northeast. Neotectonic activities and seismotectonic parts effects at each other produce a great seismicity in Iran. The Strait of Hormuz region was bounded by latitudes 26.00ºN – 29.50ºN and longitudes 55.00ºE - 59.00ºE, in south of Iran. This region located between three seismotectonic provinces (Zagros, Makran and Central-East Iran). In this article for study of seismicity and seismotectonic in the Strait of Hormuz region is used modern instrumental earthquake data from International Seismological Centre (ISC) catalog, Harvard Centroid Moment Tensor (CMT) catalog and historical earthquakes catalog (Ambraseys & Melville, 1982). Shuttle Radar Topography Mission (SRTM) data is used for topography map. Geographic Information System (Arc-GIS) and Analysis of Earthquake Data (Zmap) softwares are used in this research. Analyses of seismicity in the Strait of Hormuz region indicate active seismicity in this region. The most of modern instrumental earthquakes have magnitudes about 4.0 to 4.5 in mb scale. Magnitude 4.3 has most frequency. Earthquakes epicenters compression and the greatest earthquakes (mb=6.2, 6.1, 6.0) were recorded in the area that located in the Zagros seismotectonic province. The earthquakes were occurred in crust. In the area of the Makran seismotectonic province, the most magnitude is mb=5.5 and subduction phenomenon is active. In the area of the Central-East Iran seismotectonic province, many earthquakes were recorded in vicinity of Bam fault that the most magnitude is mb=5.9. Bandar Abbas and Qeshm cities have high seismicity activity in the Strait of Hormuz region because the greatest earthquakes (modern instrumental, early instrumental and historical) were recorded in environs of these cities. Keywords: Seismicity, Seismotectonic Province, Strait of Hormuz, ISC Catalog. 1- Introduction The Iranian plateau is a relatively wide zone of compressional deformation along the Alpine-Himalayan active mountain belt, which is entrapped between two plates, the Arabian plate in the southwest and the Eurasian plate in the northeast. Its deformation is related to the continuing convergent movement between the Arabian plate and the Eurasian plate, by north-northeastward drift Arabian plate against Eurasian plate. Lithospheric movement has led Iran to be one of the seismically active areas of the world and frequently affected by destructive earthquakes, imposing heavy losses in human lives and widespread damage. Studied region is the Strait of Hormuz region that bounded by latitudes 26.00ºN – 29.50ºN and longitudes 55.00ºE - 59.00ºE, in south of Iran (Figure 1). 2- Geology of Region The Strait of Hormuz region included area that located between three seismotectonic provinces (Zagros, Makran and Central-East Iran). In the area that located in the Zagros

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seismotectonic province, bedrock was continental crustal type and included two distinctive structures (High Zagros fault and Main Zagros Reverse fault). In this area, the sequence of parallel anticline and syncline was located that have an east-west trend. Because of continuous convergent between Iranian plateau and Arabian plate, effective factors folding of the Zagros mountains are still active. So, upward movements in the Zagros mountains are associated with crustal shortening and energy centralization. Energy freeing is almost constant. In this area, numerous earthquakes were occurred. Some of these earthquakes were caused destruction and human casualties. Some of the major faults in this area are Main Zagros Reverse Fault (MZRF), High Zagros Fault (HZF), Zagros Foredeep Fault (ZFF) and Mountain Front Fault (MFF). In another area that located in the Makran seismotectonic province, oceanic crust of Arabian plate driven down continental crust of Iranian plateau by phenomenon of Subduction. So type of bedrock is oceanic crust. Subduction phenomenon is active now. Structures have east-west trend. Minab fault system is the most important system in this area that caused considerable deformation in its adjacent structures. Jiroft and Sabzevaran faults were located in this area. The Central-East seismotectonic province was located in the northern and northeastern areas of the Strait of Hormuz. The type of bedrock is continental crust that may be transformed ultramafics. Golbaf, Bam and Jebal Barez faults are important faults in this area. 3- Seismicity and Seismotectonic of Region Seismotectonic map of studied region is showed in figure 2. Earthquake parameters (epicenter and magnitude) for modern instrumental earthquakes are according to International Seismological Centre (ISC) catalog from 1964/03/11 to 2007/10/18. In this interval time 1147 earthquakes were recorded with magnitude from 3.1 to 6.2 in mb scal. The greatest modern instrumental earthquakes recorded in this region, were showed in tables 1, 2 and 3 for each seismotectonic province. Earthquakes epicenters compression in the Strait of Hormuz region was located in the Zagros seismotectonic province. Earthquakes focal mechanisms were gotten from Harvard Centroid Moment Tensor (CMT) catalog and the most of them are strike-slip and reverse faulting that adapted with local faults. Earthquake parameters for early instrumental and historical earthquakes are according to Ambraseys & Melville (1982) catalog. The greatest early instrumental and historical earthquakes were showed in tables 4 and 5. In this region, 12 early instrumental earthquakes were recorded from 1900 to 1964 in Ms scale. The greatest one was occurred in 1902 with Ms=6.4. Also 7 historical earthquakes were recorded before 1900. The greatest one was occurred in 1497 with Ms=6.5. Figure 3 shows Frequency of modern instrumental earthquakes versus magnitude. The most of earthquakes have magnitudes about 4.0 to 4.5. The most frequency is associated with mb=4.3. Figure 4 shows depth distribution of modern instrumental earthquakes. In this figure, five earthquakes with the greatest magnitudes were denoted. The most of recorded earthquakes are in low focal depths, but in southeastern of region, focal depths are increased in upper latitudes. 4- Conclusion The Strait of Hormuz region is very active in seismicity. With ISC catalog, the most of earthquakes have magnitudes about 4.0 to 4.5 in mb scale and the most frequency is associated

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with mb=4.3. The greatest earthquakes (mb=6.2, 6.1, 6.0) were recorded in the area of the Zagros seismotectonic province. The most of earthquakes were accrued in this area. So this area has the greatest seismicity activity. The most of earthquakes are in low depths and they were occurred in crust. In southeastern of the Strait of Hormuz region (Makran seismotectonic province), focal depths are increased in upper latitudes. Therefore subduction phenomenon is active in this area. In other area that located in the Central-East Iran seismotectonic province, many earthquakes were occurred in the vicinity of Bam fault. The greatest earthquakes were recorded in environs of Bandar Abbas and Qeshm cities. Therefore these cities have high seismicity activity. References

[1] Aghanabati, S., A., 2005, Geology of Iran, Geological Survey of Iran Press, Tehran, Iran.

[2] Mirzaei, N., Mengtan, G., Yuntai, C., Seismic source regionalization for seismic zoning of Iran: Major seismotectonic provinces: 1998, Journal of Earthquake Prediction Research, v. 7, p. 465� 495.

[3] Berberian, M., 1995, Master blind thrust faults hidden under the Zagros folds: Active basement tectonics and surface morphotectonics: Tectonophysics, v. 241, p. 193� 224.

[4] International Seismological Center catalog: UK, available online at: http://www.isc.ac.uk.

[5] Centroid Moment Tensor catalog: Harvard University, Department of Geological Sciences, available online at: http://www.globalcmt.org/CMTsearch.html

[6] Ambraseys, N. N., Melville, C. P., 1982, A history of Persian earthquakes: Cambridge University Press, Cambridge, UK.

Table 1: The greatest modern instrumental earthquakes recorded in the Zagros seismotectonic province.

Event Time (yr)

Latitude (deg)

Longitude (deg)

Magnitude (mb)

Epicenter

1 1977 27.59 56.38 6.2 45 km in north of Bandar Abbas 2 1990 28.23 55.47 6.1 43 km in west of Hajiabad 3 1999 28.28 57.20 6.1 68 km in southwest of Jiroft 4 1971 28.30 55.61 6.0 30 km in west of Hajiabad 5 2005 26.75 55.83 6.0 50 km in southwest of Qeshm

Table 2: The greatest modern instrumental earthquake recorded in the Makran seismotectonic province. Event Time

(yr) Latitude (deg)

Longitude (deg)

Magnitude (mb)

Epicenter

1 1983 26.89 57.59 5.5 57 km in south eastern of Minab

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Table 3: The greatest modern instrumental earthquake recorded in the Central-East Iran seismotectonic province. Event Time

(yr) Latitude (deg)

Longitude (deg)

Magnitude (mb)

Epicenter

1 2003 28.97 58.30 5.9 15 km in southwest of Bam

Table 4: The greatest early instrumental earthquakes recorded in the Strait of Hormuz region. Event Time

(yr) Latitude (deg)

Longitude (deg)

Magnitude (Ms)

Epicenter

1 1902 27.00 56.00 6.4 27 km in west of Qeshm 2 1949 27.22 56.42 6.3 15 km in east of Bandar Abbas 3 1930 27.88 55.02 6.1 100 km in southwest of Hajiabad

Table 5: The greatest historical earthquakes recorded in the Strait of Hormuz region.

Event Time (yr)

Latitude (deg)

Longitude (deg)

Magnitude (Ms)

Epicenter

1 1497 27.20 56.30 6.5 3 km in east of Bandar Abbas 2 1897 26.90 56.00 6.4 27 km in west of Qeshm

Figure 1: Topographic map of the Strait of Hormuz region by SRTM data.

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Figure 2: Seismotectonic map of the Strait of Hormuz region.

Figure 3: Modern instrumental earthquakes frequency versus magnitude.

Figure 4: Depth distribution of modern instrumental earthquakes in the Strait of Hormuz region.

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An Artificial Neural Network Approach to Evaluate Cation and Anion changes in Electrical Conductivity Change procedure in Underground water resources, Case Study: Damghan Plain, Semnan Province, Iran

Mohammad Ahmadi*, A. Fazeli Oladi1, Reza Pirmoradi2, S. Partani3

Corresponding author: MSc. Student of civil Engineering, Bu Ali Sina University, Hamedan, Iran.

E-mail address: mohammad_ahmadi8m@yahoo . Tel: +98-912-2974529

Abstract Ions, which have positives or negative Electrical charge that could be called as cation and anion respectively, could be classified as one of the effective and important factors in underground water table quality. In this way and in order to Electrical conductivity potential of water which contained with ions, Electrical Conductivity (EC) have been defined as a quality index in underground water resources. Solution of ions in water could be affect this index; for example, the EC of pure water is less than the same water when it contains ions and increasing the amount of solved ions could be increased the EC index. In presented research, by employing chemichal analyze samples which get from Damghan plain in semnan province, an Artificial Neural Network (ANN) which could estimate EC of underground water by using cations and anions has been designed. By random selection of about %80 of mentioned samples, ANN has been trained and with %20 of them, estimator network has been validated. Comparison of observed and estimated values gives any suggestions about efficiency and accuracy of designed ANN. In this way, application of any statistical indices, could be useful for assessing accuracy and efficiency of designed network. Finally, to evaluate cations and anions changes and them effect on change rate of EC in underground water table of Damghan plain, sensitivity analysis of ANN input variables4 have been conducted. These variables effect on EC changes has been encountered and any conclusions have been extracted. Keywords: underground water; Artificial Neural Network; Sensitivity Analyze; EC; 1- Introduction The amount of soluble salts could be mentioned as the indices for expressing quality of surface and subsurface water resources. In this regard, some ions such as Ca2+ ،Na+ and Mg2+ which are classified as cations and some others such as So4

2- ،Cl- and HCo3- that identified as

anions compared with other salts are more important. It should be mentioned that Electrical conductivity of water has direct relationship with the amount of solution salts and could be said that more dissolved salts causes more EC and vice versa. In this way and for expressing the amount of salts in water, an index has defined as the Electrical Conductivity (EC). Mentioned index shows the rate of electrical conductivity of water. It should be mentioned that anions and cations and percent of their presence could be affect on this index. But the rate of effects of each salt on EC change procedure is a topic that requires more investigations. For

1 M.S.c Student of Economic Geology, Islamic Azad University, Khoram Abad Branch, Khoram Abad, Iran 2 M.S.c Student of Hydrogeology, Islamic Azad University, Science and Research Campus, Tehran, Iran 3 PhD Student of civil engineering in water and environmental engineering, Tehran University, Tehran, Iran 4 Anions and Cations

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this purpose, for assessing the rate of change procedures of target value in order to independent variables change require some methods which describe relationships with mathematical equations. Artificial Neural Network method, which is the following set of meta-heuristic methods, could discover the hidden relations between system parameters. This method has the ability to discover the relation between target value and independent variables by employing the observed data set. In this way, employing best Artificial Neural Network for prediction, which by handling special topology, learning rule and transfer function can predict the objective value in non-measured locations, seems essential. Sensitivity analysis of changes of independent variables on change procedure of EC and anions and cations influence on electrical conductivity is one of the most interesting research fields for hydrogeological studies. Mentioned subjects with more detail have been provided in next sections. 2- Location of Study Area The study area is located in Semnan province in the center of Iran and its coordinate has been limited between 53° 21' 00" and 54° 43' 44" eastern hemisphere and 35° 42' 38" and 36° 32' 06" northern hemisphere. The area of study area is about 5905 square kilometers. The main city in study area is Damghan and Damghan township is its center. Location of study area has been shown at figure (1). 3- Methodology First of all, gathering dataset from qualitative data sources such as observation wells and any exploration logs has been done. Then, qualitative analysis and some experiments have been carried out. ANN Design, finding the best transfer function, learning rule and number of processors in neuron, Validating ANN, extracting weights and employ them in a calculation could be mentioned as the next steps. Eventually, the Sensitivity analysis has been encountered. The mentioned steps, has been shown in figure(2). 4- Overview of Neural Networks McCulloch and Pitts (1943) developed the first artificial neuron. However, it was not until the psychologists David Rumelhart, of University of California at San Diego, and James McClelland, of Carnegie-Mellon University, developed the back-propagation algorithm for training multi-layer perceptrons, that interest in ANNs flourished [1]. Recently, ANNs have been applied extensively to many prediction tasks. ANNs are able to determine the relationship between a set of input data and the corresponding output data without the need for predefined mathematical equations between these data. Artificial neural networks (ANNs) are a form of artificial intelligence which, in their architecture, try to simulate the biological structure of the human brain. ANNs try to mimic the behavior of the basic biological and chemical processes of ANNs. ANNs learn “by example” and therefore are well suited to complex processes where the relationship between the variables is unknown [2]. Many authors have described the structure and operation of ANNs [3]. ANNs consist of a number of artificial neurons (variously known as “processing elements”, “PEs”, “Nodes” or “Units”) representative of the neurons in ANNs. Each processing element has several input paths and one output path, as shown in Figure (3). An individual PE receives its inputs from

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many other processing elements via weighted input connections. These weighted inputs are summed and passed through a transfer function to produce a single activation level for the processing element, which is the node output. A typical structure of artificial neural networks consists of many processing elements that are arranged in layers: an input layer, an output layer, and one or more layers in between, called intermediate or hidden layers .Each processing element in a specific layer is interconnected to all the processing elements in the next layer via weighted connections. The scalar weights determine the strength of the connection between interconnected neurons. A zero weight refers to no connection between two neurons and a negative weight refers to a prohibitive relationship [3]. The propagation of information starts at the input layer where the input data are presented. The inputs are weighted and received by each node in the next layer. The weighted inputs are then summed and passed through a non-linear transfer function to produce the node output, which is weighted and passed to the processing elements in the next layer. The network’s output is compared with the actual value and the error between the two values is calculated. This error is then used to adjust the weights until the network can find a set of weights that will produce the input-output mapping with the smallest possible error [3, 4 and 5].

Figure (1): Location of study area and hydro-meteorological stations

Figure (2): Methodology of this study

Figure (3): Typical processing element (PE) in a neuron [3]

5- Input datasets In this research for design of artificial neural network, an extended data set has been employed. The data set has been derived from Damghan plain in Semnan province. The location of mentioned data set has presented in figure No. 1. This data includes the location of observations and amount of anions and cations which has been extracted [6].

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6- ANN Design for Calculating EC in order to the Anion and Cation Amount Multi-Layer Perceptron ANN with learning rule on back propagation was design for calculation of EC based on anions and cations. As it's said before, the learning rule of this ANN is back propagation and hyperbolic tangential transfer function has been applied in the neural cells. The ANN has eight entrances, one hidden layer including one processor neural cell and one estimated output result; in afterward it will be called MLP BP TANH 2-1-1 in abbreviation. Synaptic weight and bias term weight is shown in figure (4). In this figure the equations used in processor cells for estimating outputs has been presented. Following, using the output results of ANN and comparing them with observed data, the ANN verified [7].

Figure (4): Synaptic weight and bias term weight in designed ANN

7- Sensitivity Analysis of Anion and Cation Change on EC change Procedure As can be seen, in order to EC estimation, first of all designed ANN verified in observed and planned points. Then using the ANN equations and applying them on main layers of data and by using topology, effects of main input layers on EC can be investigated. The effects of main layers on annual mean precipitation is shown in figure (5).

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8- Conclusion and Results • According to presented figures in section number 6 and 7 it can be said that anion change has more effect on the rate of change procedure of EC. Change of HCo3-, So42- and Cl- ions has the most rules in EC changes within anions, respectively. Within cations, Na+, Mg2+ and Ca2+ play the most rules on EC change procedure, respectively. Ca2+ change has the lowest effect on EC change procedure. • By employing the ANN method, hidden relations between system parameters could be

carried out. Having in hand these relations that could be expressed by equations, review of system elements could be encountered, also the influences of independent variables on target value could be carried out. • The accuracy of investigations preliminary depends on the ANN model accuracy. And eventually, application of statistical analysis and statistical indices for estimator selection is inevitable.

0

20

40

60

80

100

120

Na Mg Ca Cl Hco3 So4The

Effe

ct o

f Ani

ons

and

Cat

ions

on

EC(D

imen

tion

Less

)

Figure (5): The effect of Anions and Cations on EC in a Dimension less Diagram

Acknowledgment The assistance and technical support of Pangan Avaran Consulting Engineers for providing the data base of presented research kindly acknowledged. References

[1] Rumelhart, D. E., Hinton, G. E. and Williams, R. J., “Learning internal representations by error propagation” In: D. E. Rumelhart & J. L. McMlelland, Eds. Parallel Distributed Processing, 1, Chapter 8, Reprinted in Anderson & Rosenfeld (1988), 675-695, 1986.

[2] Hubick, K. T. (1992). “Artificial neural networks in Australia” Department of Industry, Technology and Commerce, Commonwealth of Australia, Canberra.

[3] Shahin M. A., Jaksa M. B., Maier H. R., “Predicting the Settlement of Shallow Foundations on Cohesion less Soils Using Back-Propagation Neural Networks”, Department of Civil & Environmental Engineering, University of Adelaide, Research Report No. R 167, February, 2000.

[4]Goh, A. T. C., ”Empirical design in geotechnics using neural networks”, Geotechnique, Vol. 45, No. 4, 709-714, 1995.

[5]Xiaohong Li, Xinfei Wang, Yong Kang, and Zheng He, “Artificial Neural Network for Prediction of Rock burst in Deep-Buried Long Tunnel”, Springer, Verlag Berlin Heidelberg, pp. 983-986, 2005.

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[6] Pangan Avaran Consulting Engineers, Surface and Sub-Surface Water Resources Data Gathering Project, semnan province, 2007.

[7] Ahmadi M., Partani S., Parsoon M., “GEOGRAPHIC INFORMATION SYSTEMS ARTIFICIAL NEURAL NETWORKS COUPLING MODEL TO PREDICT MEAN ANNUALY PRECIPITATION IN STUDY AREAS, CASE STUDY: DENA SUBBASIN, KOHGILOUYE PROVINCE, IRAN”, Proceeding of International Multidisciplinary Scientific Geo-Conference and EXPO Sgem, pp 191-198, 2009.

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Geo-Statistics and its Application for Creating Iso Maps in Hydrogeological Studies, Technical Study: Electric Conductivity contours of Atrak Plain,

Golestan Province, Iran

Mohammad Ahmadi*, Peyman Shirin Zade1, Behrouz Yaghoubi2, Mostafa Safari Komeil3

*Corresponding author: MSc. Student of civil Engineering, Bu Ali Sina University, Hamedan, Iran. E-mail address: mohammad_ahmadi8m@yahoo .

Tel: +98-912-2974529

Abstract With taking discrete sampling from the water resource parameters in quantity and quality and the use of procedures of turning discrete spots to connected area one can study the process of the surface changes of selected area. There are different procedures for turning broken discrete spots to continuity of areas such as procedure of Geostatistics which conclude Kriging procedure, Inverse Distance Weighting (IDW), Radial Basis Functions (RBF), Local Polynomial Interpolation, Global Polynomial Interpolation and Co-kriging. This research is going to explain any applications of Geostatistics for creating iso-maps such as underground water table contours, iso-quality (for example Ec and pH) contours, and place changes of too many other hydro-geological parameters. In this way, statistic signs such as Mean Absolute Error (MAE), Mean Absolute Relative Error (MARE), Root Mean Square Error (RMSE), MBE and Coefficient of Correlation, could be employed to select the best Geo-Statistic model in a GIS framework. Eventually, the power in IDW method has been optimized and also best Geo-Statistic method has been introduced for predicting the Electric Conductivity (EC) of underground water in Atrak plain. Finally any conclusions have been extracted. Keywords: Geo-statistics; underground water quality; statistic signs; GIS. 1-Introduction Change procedure assessment of objective value in study area could be obtained by discrete sampling of variable. In this regard, increase or decrease evaluation of objective value and extracting the critical points in study area could be classified as one the most important technical problems for geo-science researchers. The accuracy of future studies which have been based on these sampling and also change procedure studies of target value in study area, have directly depended on the accuracy and efficiency of data gathering and the procedure of turning discrete spots to continuous surface. It means that, the exactitude of future studies has widely depended on the certitude of spot point to contour map conversion method. There are too many ways to create iso-maps from spot sampling, Geo-Statistics (G.S) could be explained as one of these methods. The Geo-Statistics method divided into some sub-methods such as Inverse Distance Weighting (IDW), Radial Basis Functions (RBF), Global Polynomial Interpolation (GPI), Local Polynomial Interpolation (LPI), Kriging and Co-Kriging methods. This prediction approach, could estimate target value on non-measured points in the study area more accurate than the classic procedures such as Triangular Irregular Network (TIN). It should be mentioned that in Geo-Statistics, there are some constant

1 River Engineering Department of Yekom Consulting Engineers, Tehran, Iran. 2 Director of Integrating and Balance of Water Resources, Hamedan Regional Water Co., Iran. 3 M.S.c Student of Hydrogeology, Shahid Beheshti University, Tehran, Iran.

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coefficient that they are effective on the accuracy of estimation. In this respect, a statistical index, which has called Root Mean Squared Prediction Error (RMSE), could be defined for selecting the best Geo-Statistic estimator and finding the optimized constant coefficient. Mentioned index, which has show differences between observed target value and the predicted one in non-measured points, could help the researcher to find the best estimator and optimized constant coefficients. Best estimator should have minimum value of RMSE. In presented study, by employing the results of qualitative analysis of underground water samples of Atrak plain in Golestan province, the best G.S estimator has been selected for predicting the Electrical Conductivity of underground water in mentioned study area. 2-Methodology Selecting the best Geo-Statistics estimator to predict Electric Conductivity1, and also power optimization of IDW method could be considered as the main purpose of presented study. Figure No. 1 describes main steps of this research. 2-The Location of study area Atrak plain is located in Golestan province with the area of 3257 square kilometers. This study area has a plain in its central zone. Figure No.1 shows the location of the study limit along with the limit of Atrak plain.

Figure 1. Research Methodology 1-Geo-Statistics 2-Inverse Distance Weighting 3-Local Polynomial Interpolation 4-Global Polynomial Interpolation 5-Kriging model (Based on D. G. Krige theorem)

Figure 2. Location of Study Area

4-Introduction related to the procedures of Geostatistics In general Geostatistics procedures are based on Regionalized Variable theory. Regionalized Variable refers to every environmental feature distributed in two or three dimensional space. The changes of this set of variables from one point to another are clear and their continuity is obvious. The features such as the Electrical Conductivity, texture of soil and/or the amount of different elements in soil are examples of the regionalized variables. The major difference between classic statistics and Geostatistics is that it is assumed that the samples collected

1 . EC

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form society are not depend on each other in classic statistics ,therefore the existence of one sample does not give any information about the other samples located in certain distance. For example, Kriging procedure based on models and statistical procedures is auto-correlation. It is an estimator based on the logic of weighted moving average and it is an unbiased estimator and it is determined by the use of Krige's formula. The equation no.1 shows how it is estimated in Kriging procedure. In Inverse Distance Weighting or IDW method, the amount of one quantity in spots with known coordinate can be attained by the use of quantity of the same amount in other spots with known coordinate. In other words in this procedure the value of one variable is counted based on the mean of neighbors in specific zones. Equation No. (2) describes the IDW prediction procedure. Radial Basis functions are a procedure contains 5 kinds of radial functions as explained through following words. There is not a big difference among the results of different functions in RBF procedure and the selection of the radial basis function happens by validating the estimate results. The equations no.3 and 4 introduces some of these functions such as CRS and SWT respectively. The CRS function is used in this research. The procedures and the functions of RBF are the especial form of Artificial Neural Networks (ANN).

∑=

=n

iii xzxz

1)(.)(ˆ λ (1) ∑

∞

=

++=−

−=1

21

22

)2.()

2.ln(

!.)1()(ˆ

nE

nn

CrErnnrrz σσ (3)

∑=

=n

iii xz

nxz

1

)(1)(ˆ (2) ECrKrrz ++= 20 ).()

2.ln()(ˆ σσ (4)

In which z(x) is the estimated parameter and .λ.is the weight or the significance of the quantity that depended on ith sample and z(xi) is known parameter and )(ˆ xz is the estimated parameter and )( ixz is known parameter [1,2,4,5,6, and 7].In these equations No. 3 and 4, σ

is Tension Parameter, E1 is Exponential Integral Function, EC is Euler Constant, and 0K is Modified Bessel Function [8]. 5-Establishing and Validating Geostatistics Model In this stage with the use of GIS and random procedure, establishing samples, and validating samples of models are 80 and 20 percent of the whole selected data bank, and are recalled in cyber space in the form of two separate layers. After this stage, Kriging models, IDW, and RBF are established and validated. The results of models are shown in the figure no.4. One of the criteria in examining of the validity of the attained results from models is the criteria of Coefficient of correlation (r); whatever its absolute value gets closer to 1 the better adaptation between the observed amounts is shown. But with the use of just Coefficient of correlation one can not declare anything about the efficiency and the accuracy of the model; therefore other parameters and statistics will be used for examining the designed models. In this regard the criteria of Root Mean Square Error (RMSE), Mean Absolute Error (MAE), and Mean Bias Error (MBE) have been employed. The equations number (5) to (8) shows these parameters in order. The amount of stated parameters in both stages of establishing (education) and validating (test) of Geostatistics models are shown in table no. 1 [7 and 8].

∑

∑

=

=

−−

−−=

n

iii

n

iii

OOpp

OOppr

1

22

1

)()(

))((

(5) ∑=

−=n

1i2)iPi(O

n

1RMSE

(6) ∑=

−=n

iii PO

nMAE

1

1

(7) ∑

=

−=n

iii PO

nMBE

1)(1

(8)

450


In these equations, iO is the observed amount, iP is the predicted amount and n is the number

of observations. The above introduced features are the whole statistical indices which do not provide any information about the procedure of error distribution; therefore for evaluating the capacity of the models, statistical features are needed which specifies how the error distribution in the established models. For this reason the Mean Absolute Relative Error distribution diagram for final evaluation of used models (besides statistical parameter) is used. 5-1-Optimization of Power in IDW Model and selection of best G.S1 Model In this section, by taking the results of Kriging, RBF, GPI, LPI and optimized IDW method, the best estimator which belongs to the minimum of RMSE2 has been extracted. For this purpose, first of all optimization of power in IDW method has been carried out. 5-1-1- Power Optimization The best and accurate estimation of objective value could be mentioned as the main purpose of G.S. In this regard, constant coefficient optimization to reach the minimum RMSE plays the main rule. This part of research wants to optimize the power in IDW method as an example for constant coefficient optimization. Comparison between results of optimized models with non-optimized models expresses the necessity of linear of nonlinear optimization in such these studies. Figure No. 3 shows the relationship between RMSE and power variation in IDW results. By having in hand the results which has presented in mentioned Figure, The optimized power in IDW method is 1.38 and the results that related to this power have the minimum RMSE. 5-1-2- Best Estimator Selection As it noted in paragraph No. (5-1-1), this research aims to provide an optimal method for calculating the objective value in non-measured locations, change procedure studies and create Iso-Maps for presenting the change surface of variable in Raster maps in a GIS frame work. For this purpose, having in hand the estimated results with different G.S methods and incorporate statistical index Correlation Coefficient (r), RMSE, MAE and MBE, the best estimator could be extracted. In order to table No. 1, Kriging Method has the best correlation between estimations and measurement and the minimum RMSE. Also, by employing the results which has been presented in fig no. 4, kriging method has the best Mean Absolute Relative Error (MARE) (the MARE of more than %89 of datasets in test stage is less than %38), so the Kriging Geo-Statistic method could be introduced as the best EC estimator in Atrak plain.

Table No. 1: Comparison of Statistical Indices for Best Estimator Selection G.S Method r RMSE MBE MAE Kriging 0.81 2200 485 1740 RBF 0.79 2263 427 1662 GPI 0.63 2981 347 2031 LPI 0.64 2942 349 2002 Power Optimized IDW 0.459 4816 -183 2845

1 Geo-Statistics 2 Root Mean Squared Prediction Error

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0102030405060708090

100

0 10 20 30 40 50 60 70

Mean Absolute Relative Error (%)

GPI

LPI

RBF

Kriging

Num

ber o

f Obs

erva

tions

(%)

Figure No. 3: Power optimization in IDW method and the minimum of RMSE

Figure No.4: Evaluation of Mean Absolute Relative Error change in Number of Data sets for evaluated Methods

6-Results and Conclusions • With the use of Geostatistics procedures and statistical analysis of results it is tried to find out the best estimator of Electric Conductivity in the points apart from the measured points in Atrak plain .The best estimator is kriging model respecting part No.5-1-2. • Respecting to this point that determining place changes of some quantity and quality parameters are counted as the input data of other stages of water resource study, selecting the best estimator model and its careful estimation has a direct influence on the carefulness of further stages. 7-Suggestions • Optimization of constant coefficients such as tension parameter in RBF procedure, in Geostatistics models and the comparison of different procedures happen in the presence of optimized factor. • The comparison of the results of Geostatistics procedures and the procedure of Triangular Irregular Network (TIN) in providing the map of the iso-level of EC. References

[1] Ghohroudi Tali, Manije, "Geographic Information System in Three Dimensional Environment, Three Dimensional GIS in Arc Gis Environment", Jahad Daneshgahi publication of Tarbiat Moalem University, first edition, spring 2005.

[2] Sanjeri. Sara, "GIS Training in use", Abed publications, 3rd edition, 2008.

[3] Mohammadi Jahangard, "Geostatistical Evaluation of salt changes of soil in Ramhormoz zone, 1- Kriging Method", Scientific and technical studies of Agriculture and Natural Resources Journal, Vol 2, Number 4, Winter 2007.

[4] C.P. Lo, Albert K. W. Yeung, “Concepts and Techniques of Geographic Information Systems”, Prentice Hall of India Private Limited, New Dehli, 2005.

[5] Ahmadi M., Partani, S., Zabihi M., "GIS Application in Climate-Microzonation in hot and arid areas, Case study: Raze2 Dam", Proceeding of the 1st International conference on Water crisis, Zabol University, winter 2009.

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[6] Mohammadi Jahangard, "Geostatistical Evaluation of salt changes of soil in Ramhormoz zone, 1- Kriging Method", Scientific and technical studies of Agriculture and Natural Resources Journal, Vol 3, Number 1, spring 1999.

[7] Ghohroudi Tali, Manije, "Establishing and Modification methods of creating elevated models, Case study: Golestan 2 Dam", Geographic Researches Journal, Number 57, fall 2006.

[8] Asadian F., Ahmadi M., Arzjani Z., Partani S., Pirmoradi R., " A Comparison of Different Procedures of Geostatic in the Study of Place Changes of the Level of Underground Water by GIS (A Case Study of Razan-Ghahavand Plain in Hamedan Province, Iran)", Proceeding of International Conference on Water Resources (ICWR2009), Shahroud University, Summer 2009.

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Investigating the role of Geological Formation on mass movement occurrence Case study: Bar watershed)

Mohamad Razavi Moghadam*, Mohsen Padyab

Dr. Sadat Feiz Nia, Dr. Baharak Motamed Vaziri

Corresponding author: MSc Student of Science and Research, Azad University E-mail address: [email protected]

Abstract Iran, because of its special geographical conditions of various geological and geomorphologic properties and also diversity of climate, is challenging with many different catastrophes including mass movement which cause plenty of damages. Geological factor, especially type of geological formation is considered as an innate element to occur mass movements. To determine different geological formation tendency on mass movement occurrence, it is necessary to consider mass movement density occurring on different geological formations. In this study, performed bar domain, with area of 5399 hectares, that is 33 km far from north of Neyshaboor, numerical layers of geological formation and mass movements have been provided in GIS in order to estimate the effect of each formation on mass movement occurrence. Then diagrams have been drawn by statistical software and finally area percentage of each type of mass movement on formations of the zone has been provided. The results showed that Delichay formation and Lar formation have the most effect on mass movement occurrence and 54.3% and 40.2% of area mass movements occur on them, respectively. Key words: Geology, Mass movement, GIS, Delichay formation, Lar formation 1- Introduction Land morphology usually indicates the type of land materials, resistance of this material to erosion, soil permeability, erosion type and flooding hazard. The geology factor always, has a major role in creating of landslides. Iran in terms of specific geographic location has different geological zones and constructor variety of Geology (Prkambryn to the present covenant). This material layers are always under stress of deformation because the Alps Himalayas belt is near and has grown tectonic structure types such as faults and joints and fractures. This transformation reduces the resistance of the stone mass and caused increase mass movements. On the other hand, exposure this material in various weather of Iran, affect the types of weathering on the geological materials and in this case, density and type of Landslides will be different due to various in climates, sedimentation zones and structural geology. This matter caused to researchers with various studies of mass movements occurred; pay attention to role of factors involved in this phenomenon, especially the role of Geological formations on Landslides. The research results from this article express effects the constructor geology and the role of structural differences had in the occurrence and distribution of many types of mass movement. Chang and colleagues [5] review and zonation effectives factors of mass movements occurrence in the Hoshe basin (Taiwan Center) that area were 92 kilometers. The results indicated that geological formation is important factor of mass movement factors. Tangestani

454


[11], research the roles of geology factor, slope angle, slope direction, land cover and soil depth on Landslide occurrence in the Kakan basin (located northwest of Shiraz) and reached to this conclusion that formation type have effective role on Landslide. Yalcin [12], attempted to review factors mass movement in the 40 basin of Ardesen (located in the north-eastern Turkey) was an area of 50 kilometers, and concluded that factors such as region formation, degree of slope and land cover are more effective in the occurrence of Landslide. Shirani and colleagues researches [10] also showed that in Semirom of Isfahan, geology role had most important factor among the factors in mass movement occurrence. 2- Materials and Methods 2-1 Features the study area Bar Watershed with 5,399 hectares area that is 33 km far from of north Neyshaboor city between 65.04 and 66.11 Geography altitude and 40.39 in latitude. It region in spring and summer have a mild weather but in winter is very cold and have many snow. Average of area rainfall is 338 mm. This region contains Mesozoic stone and quaternary sediments. Minimum and maximum of elevation are, respectively, 2900 meter and 1580 meter and average slope is 39 degrees. This region has many faults that one of important of faults is Bar fault. (Appendix 1) 2-1-1 watershed Geology First time Eshtoklin with considering the complexity of the structure and different sedimentary conditions divided Iran to several separate structural sedimentary basin. Then the other studies provided more comprehensive and complete divisions that can noted to Nabovati (1355) [9] Eftekhar nejad (1359) [7] Brbryan (1373) [4] Alavi (1996) [2] Agha nabati (1383) [1]. Region based on Nabovati Studies (1355) [9], and Darvish Zadeh (1383) [6] is located in the Alborz zone on under zone of Geology of Kope dagh and eastern Alborz (Binalud). Formation in this area is to follow: Delichay Formation (Jd) The unit consists of light gray marn with limestone is between the layers with about 100 meters thickness. It is the result of become more relaxed environment of sedimentation at this time. In this formation are visible Brakiopud and Ammonite Fossils that are specified for the unit the Middle Jurassic age to early upper Jurassic. The Ammonites Find in this collection can be name Parkinsonis sp and Oppella subroliata. In much of the regions, this formation is directly metamorphosed on the Carboniferous - Triassic units. In this case, cut faults can be seen in the low surface of layer that it is result of pushed to them on another. Surface example of this formation is in the right side of Delichay River (Firouzkooh way to Tehran). [6] It is thickness about 110 meters. Delichay (Jd) Formation consists of marl and thin layer of sand limestone that it color is green and Sometimes the marl shale seems between layer. Underside it can be seen Lime Alit with Limonitic Rubbles and sometimes muddy splits. Delichay formation was sensitive to erosion. [8]

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Lar Formation (Jl) Gray marn Delichay Formation toward high-level in a gradually contact convert to limestone with pea color. This unit includes two sections. Underside is consists of the mass limestone to thick layer and the upper layer is consists of medium limestone layers which layers are clearly defined. Thickness of this collection is about 260 meters. High resistance of the lime and Non-resistance of older units of stone in front of erosion caused to this limestone create high topography. Lithacoceras sp and Ataxioceras sp that found in this formation are Ammonites. Sample point of Lar formation is Lar Valley in Central Alborz. Thickness formation is between 250 and 350 meters. This formation composed of thin layer from Mykrity limestone to mass dense with light gray color that have puddle or white cherty layers to light violet is filled with fossils. Lar formation appears in Shahrud, Semnan and Damghan on Eastern Alborz. [8] This Formation is equivalent to the upper part of Surmeh formation of the Zagros and is similar to Mozdoran formation in kope Dagh. This formation is sensitive to destruction and sometimes dissolution that is related to past wet period. [6] Shale and Jurassic sandstone (Jsh.s) This unit consists of periodic sandstone and black shale that often shales have some coal. Plant fossils that have been identified in the shales include Ginbkgoites and Kelokia with Middle Jurassic age and Glodophlebis friziensis and Cladophlebis sohabis. Based on these fossils, formation age is at the end of Jurassic to lower Middle Jurassic. Low surface of this unit has fault and the upper surface with gradually contact convert to Delichay. [6] Quaternary sediments Quaternary deposits are youngest sediments in this region and include different units. Old alluvial cones (Qt1) mainly caused the highlands and alluvial fan (Qtf) in foot of height and the beginning of the plain. Travertine deposits (Qtr) are resulting of warm springs activities and inform about Earth heating Phenomenon in the region. Young alluvial terraces (Qt2) mainly in the lowest point are covered to plain floor and deposit around the drainage rather than old alluvial terraces. Young flood sediments (Qal) in the path have been caused rivers and channels. Sand Hills (Qs) appear in plain floor and points that have more severe winds. Clay zones (Qc) and salt zones (Qsm) deposits in plain floor and flood plains path. [6] 2-2 Research Methodology To determine different geological formation tendency on mass movement occurrence, it is necessary to consider mass movement density occurring on different geological formations. For this purpose, we used informations that were collected from explanation air photos and satellite images. In first section, we used remote sensing techniques to recognize tumble and surge mode, then boundaries these as mass movements. After this step, referring to the Landslide database and use field study, to measure work accuracy. Researches have shown us received an acceptable result from this method. Then Import these in formations to GIS and made numeral layer of occurred mass movements and saved them in the significant database. We used the geology map to made numeral surface layers of geological formation. Numerical layers of geological formation and mass movements have been provided in GIS in order to estimate the effect of each formation on mass movement occurrence. In next step, using GIS

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to made overlay numeral layers of geological formations and numeral layers of mass movements. After this stage, check attribute tables of each layer and extracted data from area and surface of mass movements and enter to EXCEL software. Then using capability of this statistical software to compare tables and made diagrams. Finally area percentage of each type of mass movement on formations of the zone has been provided (Appendix 2) 3- Conclusion Review of this subject is indicating, if the landslide surface developed on geological formation this formation named as sensitive. With overly Layers and research attribute tables such understanding is that the total area of 5399 hectare, 1050.7 hectare of total basin surface that is equivalent to 19.4 percent have been influence under of mass movements. Analysis showed that are contributions Lar (Jl) formation and Delichay (Jd) formation, respectively, 40.2% and 57.3% of the total types of mass movements occurred in the basin surface and other formations in the basin are including a share equivalent to 5.5%. Air photos researching and review of field studies Will be determined that from derrises on basin surface, respectively, 53 percent occurred on Lar (Jl) Formation, and 47% occurred on Delichay (Jd) Formation and other formations don't had any contributions on occurred derrises. About other types of mass movements, Delichay (Jd) formation with 39% make the largest contribution and (Qal) with 5.5% make the lowest contribution. It should be mentioned that Lar (Jl) formation is allocation 24% of the other mass movements. (Appendix 3) According to these observations can be concluded to two reasons: Nature of this formation, vast of these formations in the study area. Considering these cases can be justified that the Lar (Jl) Formation due to the nature of lime is being too hard and resistant and this type of lime creating high topographic, thus accrued more derrises against environmental factors. [8] Delichay (Jd) Formation consists of marl and thin layer of sand limestone that it color is green and Sometimes the marl shale seems between layer. Due to the nature of the marn in limestone caused its tendency to absorb more water. Because of this formation is directly metamorphosed on the Carboniferous - Triassic units, in this case, cut faults can be seen in the low surface of layer that it is result of pushed to them on another and it can be a reasonable cause of more landslides. [8] It should be note that in this region, vast of these two formations than to other formations cannot be affectless to having more percentage of mass movements. (Appendix 4) References

1- Agha nabati, A., 1383, Geology of Iran. Geological Survey of Iran. p. 606.

2- Alavi, M., 1996. Tectonostratigraphic synthesis and structural style of the Alborz Mountains system northem Iran, Journal of Geodynam, v. 21, p. 33.

3- Shtoklin, E. Eftekhar nejad, J. Hoshmand zade, A., 1352. Geological review of the East Central Loot. Geological Survey of Iran. v. 22, p. 86.

4- Berebrian, M., 1373, Research and review and tectonic earthquake - Fault in Tehran and surrounding range, Report 56. p 315.

5- Chang, K. T, Chiang, S. H, Hsu, M. L., 2007. Modeling typhoon- and earthquake induced landslides in a mountain watershed using logistic regression. Geomorphology, v. 89, p. 335–347

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6- Darvish zade, A., 1383, Geology of Iran. Sepehr publication. p. 433.

7- Eftekhar nejad, J., 1359, Separation of different parts of a building in connection with the situation sedimentary basin. Journal Oil Association, v. 82, p. 19-28.

8- Feiz nia, S., 1385, Quaternary formations. University of Tehran publication. p. 82-84.

9- Nabavi, M, H., 1355. Introductory geology of Iran, Geological Survey of Iran, p. 109.

10- Shirani, K. Chavoshi, S. Ghayomian, J., Study and assessment of landslide risk methods In the Upper Padnay Semirom. Journal of Isfahan University (Basic Sciences), v. 23, p. 24-38.

11- Tangestani, M. H., 2009, a comparative study of Dempster–Shafer and fuzzy models for landslide susceptibility mapping using a GIS: An experience from Zagros Mountains, SW Iran. Journal of Asian Earth Sciences, v. 35, p. 66-73.

12- Yalcin, A., 2008, GIS-based landslide susceptibility mapping using analytical hierarchy Process and bivariate statistics in Ardesen (Turkey): Comparisons of results and confirmations. Catena, v. 72, p. 1–12.

Bar watershed (Appendix 1)

Overly landslides and Geology maps (Appendix 3) landslides map Geology map

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Jd

Jl

Jsh-s

QalQt1 Qt2

0

10

20

30

40

Jd 39

Jl 24

Jsh-s 12

Qal 5

Qt1 9

Qt2 11

percent

Jd

Jl

44

46

48

50

52

54

Jd 47

Jl 53

percent

Percent of landslide occurence (Appendix 4) Percent of derrises occurrence

Area and percent of mass movement occurrence on formations (Appendix 5)

Formation Jd Jl Jsh-s Qal Qt1 Qt2 Total Landslides 570.91 423.10 4.18 10.65 21.43 20.42 1050.71 percent 54.3 40.2 0.3 1.1 2.1 2 100

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Geotechnical and geological aspects of Amir Kabir tunnel of Tehran

Mojtaba Daneshvar1, Ebrahim Asghari2, Ali Ghanbari3, Mahmoud Shahbazi4

1. Engineering geology student, Tehran science & research campus, Azad University

2. Assistant professor of Engineering Geology, University of Tabriz

3. Assistant professor of Civil Engineering, University of Tarbiat Moalem

4. Engineering Geology student, Ferdowsi University of Mashhad

Abstract In construction of urban tunnels, site investigation and evaluating of geomechanical parameters of various layers are important. Tehran is located on alluvial deposits. These deposits are host of various tunnels, like as metro tunnels, road tunnels and water transition tunnels. This paper explains the geological and geotechnical aspects of Amir Kabir tunnel which is about 1500 m and extended between 17th Shahrivar street and Imam Ali highway at the south of Tehran. Considering the drilling results of boreholes and test pits and according to results of in-situ tests (pressurmeter, in-situ shear test, plate load test) and laboratory tests, geotechnical aspects of sediments are presented. In the greatest part of tunnel route, sediments belong to "C" series of Tehran alluvial and consisted of sandy gravel to gravely sand with some silty and sandy lenses. According to unified classification, their classification are mostly GM and GC. The depth of groundwater table along the tunnel is between 25 and 30m that is lower than tunnel line. According to results and parameters of laboratory and in-situ experiments, coarse soils are dense to very dens and deformation modules are between 25 to 50 MPa. Also, the relation of in-situ test results between laboratory test results are compared. Key words: Amir Kabir tunnel, C series alluvial, Pressurmeter, Deformation modulus. 1. Introduction Geotechnical studies play an important role in civil engineering projects, especially underground structures. This study included excavation of boreholes, test pits, laboratory and in-situ tests. Physical and shear strength parameters of subsurface layers including cohesion, internal friction angle and deformation parameters (Young modulus, shear modulus and Poisson's ratio), can be obtained by using the above tests. This paper explains the geological and geotechnical aspects of Amir Kabir tunnel which is about 1500 m and extended between 17th Shahrivar street and Imam Ali highway in the south of Tehran (Figure, 1). 2. Geology of study area Tehran alluvium has been deposited by frequent flow of floods and rivers originating from mountains to the north of Tehran city. Based on geological aspects, Tehran alluvium is divided to 4 units, A, B, C and D [6]. Respect to the study area is located on C series, a brief explanation is presented here. This alluvial formation is shaped alluvial fan near the foothills and it is transformed to silty layers with low slope. These sediments are homogeneous and includes coarse grain with cobbles at north and fine grain at south of Tehran. Center parts of

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city is transition zone of coarse to fine grain soils. Soil cementation of this unit is low to medium. In general, Tehran "C" alluvial sediments is homogeneous and due to low cementation, is more permeable than A and B alluviums units and it has high relative strength [4]. 3. Geotechnical features of Amir Kabir tunnel area For determining of subsurface conditions of study area, 12 boreholes up to 50m are drilled and some in-situ tests, sampling are conducted. Moreover 13 test pits are excavated and some in-situ tests are conducted [5]. An overall classification is conducted based on the soil grain distribution and consistency limits, that basic gravely layer (based on unified classification, GM and GC and GP-GM and GW-GM in frequency), sandy lenses (SM and SC), silty lenses (ML) are produced. Whereas, above classification is not presented true engineering judgment, obtained elasticity modulus of Plate load tests, Pressurmeter and Triaxial tests are added in above classification according to methods and equations in part 4. Then, in some places that was not possible to calculating elasticity modulus, wet density is used for alluvium and an applied classification for tunnel coarse alluvium is presented, that its obtained results are two kinds of gravely layers (G1 and G2), two kinds of sandy lenses (S1 and S2) and one kind of silty lens. These layers are recommender of study area’s soils. The differences between 1 and 2 gravely layers and 1 and 2 sandy lenses are their elasticity modulus and wet density. So that elasticity modulus of area is lower than 30 MPa, dense layers of area are more than this value. And also the extents of wet density are higher than 20 kN/m3 according to layers that is dense based on elasticity modulus. Therefore in some depth that was not possible to calculate elasticity of modulus, the extents that is higher than 20 kN/m3, is used for differences between loose and dense layers. Also shear strength parameters (cohesion and internal friction angle) are obtained based on Triaxial, Direct shear and in-situ shear tests, finally geotechnical features of area soils are presented in Table (1). Geotechnical sections of tunnel course are presented in figures (2) and (3) based on logs of bore holes and test pits. Different thickness of man made soil is 1-5 meters. The depth of water table along the project course is lower than bottom of tunnel and is measured between 25-30 meters. 4. Determination the elasticity modulus Determination of the elasticity modulus of the tunnel coarse sediments is determined by several in-situ tests (including Pressurmeter test, Plate load test, and in-situ shear test) and laboratory tests (including Direct shear and Triaxial tests). Elasticity and shear modulus of soil G are related to Poisson's ratio, according to elasticity laws, that elasticity modulus of soil is calculated by using the Direct shear tests according to equations 1 and 2. Triaxial test is also one of the methods to determine the elasticity modulus of soil. In this test, ε∆ calculated against the increased axial stress σ∆ and modulus of elasticity is obtained according to the equation 3 [3]. Es=2G (1+ν ) (1)

heightsamplentdisplacemeShear

stressShearG ×= (2)

εσ ∆∆= /sE (3)

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In addition to the above tests, Plate load and Pressurmeter tests are considered of most accurate methods for determining in-situ elasticity modulus. Elasticity modulus is calculable based on the Plate load test results according to equation 4 [1]. Equation 4 is, implemented pressure increase in load plate and soil, B is breadth of load plate, ∆ρ is settlement according to soil implemented stress increase, Iw is shape factor, that its extents is presented technical references based on plate shape and its flexibility measure [7]. Elasticity modulus is calculable also based on Pressurmeter test results [4].

ws IqBEρν

∆−

∆=21 (4)

4.1. The evaluation of Direct shear test results The obtained elasticity modulus of this test is 2.5-4.5 MPa (Table, 1). Whereas the obtained elasticity modulus of this test is less than Pressurmeter’s tests (one of the most accurate methods in obtaining elasticity modulus), it is not recommended to use in engineering judgment. Generally obtained elasticity modulus of direct shear test is lower that other obtained tests, because of the lack of implemented confining pressure on sample and its damaged. Also probable reason is, registering shear displacement in great displacements. 4.2. The evaluation of Triaxial test results Obtained elasticity modulus of Triaxial test is similar to Pressurmeter’s obtained elasticity modulus test in S1 and G1 soils. But obtained elasticity modulus of Triaxial test is lower than Pressurmeter test in G2 and S2 soils (EPMT =1.7 ETT) (Table 1). The reasons of it, are sample disturbing, testing during the drainage condition and fine grain of sample. 4.3. The evaluation of Plate load and Pressuremeter tests results Elasticity modulus obtained from Plate load test is measured only in G2 soil. The plate load modulus is highly similar to Pressurmeter modulus (Table 1). Generally, elasticity modulus obtained from these two tests with reference to the performing the Pressurmeter and Plate load tests, modulus of elasticity obtained from the two last tests is precision according to the method of pressurmeter and plate load tests, and it is suitable engineering judgment. 5. Conclusion Based on investigations, the most of the tunnel coarse sediments are related to Tehran C series alluviums and include two kinds of gravely layers (G1 and G2 groups), two kinds of sandy lenses (S1 and S2) and one kind of silty lens. The depth of groundwater table during the project area is lower than bottom of tunnel and is measured between 25-30 meters. According to results and parameters of laboratory and in-situ experiments, the soils of course density is dense and very dense. Sediment deformation modulus is between 25 to 50 MPa. In this project, using elastic modulus of Direct shear test is not suitable to engineering judgment. But the Pressurmeter and Plate load tests are recommended to estimating of elastic modulus. References

1. Bowles, J. E. (1996). "Foundation Analysis and Design", 3rd Ed.

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2. Ghanbari, A., and Mojezi, M. (1386 solar). " Pressurmeter test in Geotechnical Engineering", Asar Moaser publication (to Persian).

3. Ghanbari, A. (1388 solar). "The study of elasticity modulus of soil in the south of Tehran alluvium", Journal of Earth Sciences, No. 71 (to Persian).

4. Pahlavan, B. (1381 solar). "An investigation to deformation of coarse grained alluvium of Tehran using Pressurmeter", Ph.D. thesis, Tarbiat Modarres University (to Persian).

5. Pazhoohesh Omran Rahvar Co. (2009), " Geotechnical investigation report of Amirkabir Tunnel project".

6. Rieben, E. H. (1966). "Geological observation on alluvial deposits in northern Iran", Geological Survey of Iran, Report No. 9.

7. US Army Corps Engineers (1990), Engineer Manual (EM 1110-1-1904), Engineering and Design- Settlement Analysis.

Table 1. Geotechnical parameters of soils

Unit Title

M S2 S1 G2 G1 54.7 25.6 24.6 13.5 17.2 Fine material (%) 29 42 42 28 29 Sand (%) 17 32 33 57 54 Gravel (%) 6.7 7.2 9.3 8.9 7.8 Plasticity Index (%)

20.3 20.3 18.6 19.8 18.1 γm (kN/m3) 16 15 9 12 7 Water content (%) - 54 19 68 22 Pressuremeter

Modulus of deformation

(MPa)

20 32 21 37 22 Triaxial - - - 75 - Plate Load Test - 4.2 4 2.3 2.7 Direct Shear**

- - - 5.7 - In-situ shear test**

- - - 34 - In-situ shear test φ (deg) - 35 3537 37 Direct Shear*

24 30 29 33 32 Triaxial (φcu) - - - 31 - In-situ shear test

C (kPa)

- 4 34 3Direct Shear* 36 20 13 13 10 Triaxial (Ccu)

* Obtained from the remolded sample ** Unacceptable

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Figure 1. The location and plan of Amir Kabir tunnel at Tehran

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Figure 2. Geological section along the north tunnel (Doroudian street)

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Figure 3. Geological section along the south Tunnel (Kerman Street)

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The hydrochemical evaluation of groundwater quality in the Harzandat plain aquifer, Northwest of Iran

N. Aghazadeh 11, and A. A. Mogaddam 2

1 Department of Geology, Azad University, Urmia branch, Urmia, Iran

2 Department of Geology, Tabriz University, Tabriz, Iran

Abstract The Harzandat plain is part of the East Azarbaijan province, which lies between Marand and Jolfa cities, northwestern of Iran, and its groundwater resources are developed for water supply and irrigation purposes. For hydrogeological consideration and optimum management of groundwater resources a mathematical model as an efficient and economical tool was prepared. In order to evaluate the quality of groundwater in study area, 36 groundwater samples were collected and analyzed for various parameters. Chemical indexes like sodium adsorption ratio, percentage of sodium, residual sodium carbonated, permeability index (PI) and chloroalkaline indexes were calculated. Based on the analytical results, groundwater in the area is generally very hard, brackish, high to very high saline and alkaline in nature. The abundance of the major ions is as follows: Cl> HCO3 > SO4 and Na>Ca>Mg>K. The dominant hydrochemical facieses of groundwater is Na-Cl type and alkalis (Na, K) and strong acids (Cl, SO4) are slightly dominating over alkali earths(Ca, Mg) and weak acids(HCO3,CO3). The chemical quality of groundwater is related to the lithology of the area and the residence time of the groundwater in contact with rock materials. The results of calculation saturation index by computer program PHREEQC shows that the nearly all of the water samples were supersaturated with respect to carbonate minerals and undersaturated with respect to sulfate minerals. Assessment of water samples from various methods indicated that groundwater in study area is chemically unsuitable for drinking and agricultural uses. Keywords: Groundwater quality, Harzandat plain, Hydrochemistry, Model,Saturation index 1. Introduction Understanding the aquifer hydraulic properties and hydrochemical characteristics of water is crucial for groundwater planning and management in the study area. Generally, the motion of groundwater along its flow paths below the ground surface increases the concentration of the chemical species (Freeze & Cherry, 1979; Domenico and Schwartz, 1990; Kortatsi, 2007). Groundwater chemistry depends on a number of factors, such as general geology, degree of chemical weathering of the various rock types, quality of recharge water and inputs from sources other than water–rock interaction. Such factors and their interactions result in a complex groundwater quality (Guler and Thyne, 2004).The rapid increase in the population of the country has led to large scale groundwater developments in some areas. Intense agricultural and urban development has caused a high demand on groundwater resources in

1 Corresponding author Email: [email protected] Tel: +98 - 441 - 3440096 Address: Iran-Urmia- Azad university Urmia branch - Department of geology, Azad university of Urmia (57159-44867) .

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arid and semi-arid regions of Iran while putting these resources at greater risk to contamination (Aghazadeh, 2004; Asghari and Najib, 2006). In this study, physical, hydrogeological, and hydrochemical data from the groundwater system will be integrated and used to determine the main factors and mechanisms controlling the chemistry of groundwater in the area. 2. Description of study area The study area is part of the Aras river drainage basin and lies between latitudes 38°,35′ to 38°,45′ N and 45°,30′, to 45°,45′ E (Fig.1). The climate of the study area is semi-arid and it’s average annual rainfall and temperate is about 280 mm, 13.2Co respectively. Groundwater is an important water resource for drinking, agriculture and industrial uses in study area. Low precipitation and over-exploitation of groundwater resources in recent years has caused an extensive groundwater level decline in this plain prohibiting further development of the aquifer. From a geological point of view, the investigated area is located in the Alborz- Azarbijan zone of the Iran (Nabavi, 1976). The exposed lithological units of the Harzandat plain range in age from Devonian to Quaternary and have different hydrogeological characteristics (Fig.1). The groundwater of the study area occurs under unconfined conditions. The result obtained form drilled wells indicate that the thickness of the alluvium aquifer is average 65m (Azarbaijan Regional Water Authority, 2004). According to the results obtained from groundwater flow modeling of the study area, the values of hydraulic conductivity and the specific yields ranges from 0.5 to 2.5md-1 and 1 to 4 percent, respectively (Asghari moghaddam and Aghazade, 2006). The general groundwater flow direction in the aquifer is from SE to NW (Fig.2) and depth to water table varies from 6 to 46 m below ground level. 3. Materials and methods For to design mathematical model of the aquifer, all the necessary hydrological, climatological, geophysical and geological data were collected and analyzed. Based on this data the mathematical model of the aquifer was prepared by VISUAL MODFLOW software. In order to evaluate the quality of groundwater in study area groundwater samples were collected from 36 shallow and deep wells and springs of the area during May 2003(Fig.2). The pH and electrical conductivity (EC) were measured using digital conductivity meters immediately after sampling. Water sample collected in the field were analyzed in the laboratory for cations and anions using the standard methods as suggested by the American Public Health Association (APHA, 1995). 4. Results and discussion The abundance of the major ions in groundwater is in following order: Na>Ca>Mg>K and Cl> HCO3> SO4>CO3. Figure 3 shows that Na and Cl are dominant cations and anion, respectively and the median values of Cl exceeded 50 % of total anions in milli-equivalent unit. Minimum, maximum and average values of physical and chemical parameters of groundwater samples are presented in Table 1. The large variation in EC is mainly attributed to geochemical processes prevailing in this region and high concentrations of Na in the groundwater are attributed to cation exchange among minerals. The concentration of dissolved ions in groundwater samples are generally governed by lithology, velocity and

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quantity of groundwater flow, nature of geochemical reactions and solubility of interaction rocks. The dissolution of evaporate minerals such as halite and gypsum influences the chemistry of the water in the Harzandat plain aquifer. Saturation indexes are used to evaluate the degree of equilibrium between water and minerals (Langmuir, 1997; Drever 1997; Coetsiers and et al., 2006). The saturation indexes were determined using the hydrogeochemical equilibrium model, PHREEQC for Windows (Parkhurst and Appelo, 1999). The saturation index of a mineral is obtained from equation (Garrels and Mackenzie, 1967). SI = log (IAP/Kt) where IAP is the ion activity product of the dissociated chemical species in solution and Kt is the equilibrium solubility product for the chemical involved at the sample temperature. In Table 1 the SI for calcite, dolomite, anhydrate and gypsum are shown. Nearly all water samples were supersaturated with respect to calcite, dolomite and aragonite and all samples undersaturated with respect to gypsum and anhydrite, suggesting that these carbonate mineral phases may have influenced the chemical composition of the study area. The values obtained from the groundwater samples analyzing, and their plot on the Piper's diagrams (Piper, 1944) reveal that the major cation is Na and the anion is Cl (Fig.4). In the study area, the major groundwater type is Na-Cl, and alkalis (Na, K) are significantly dominating over the alkaline earth metals (Ca, Mg). The sodium-chloride water type in study area is due to the low velocity of groundwater, long time contacts of water and formations as well as the type of the rocks. The analytical results have been evaluated to ascertain the suitability of groundwater of the study area for drinking and agricultural uses. The drinking water quality is evaluated by comparing with the specifications of TH and TDS set by the WHO (1989). Assessment of water samples according to exceeding the permissible limits prescribed by WHO for drinking purposes indicated that all of the groundwater samples is very hard water and groundwater in study area is chemically unsuitable for drinking uses (Table2). Salinity and indexes such as, sodium absorption ratio (SAR), sodium percentage (Na %), residual sodium carbonate (RSC), and permeability index (PI) are important parameters for determining the suitability of groundwater for agricultural uses (Ragunath, 1987; Srinivasa, 2005; Subramani, 2005; Raju, 2006). The SAR values range from 1.2 to 19.2. According to the Richards (1954) classification based on SAR values, %83 of samples is belong to the excellent category, %11 of them is belong to good category and the remaining samples are belong to the doubtful category. The Wilcox (1955) diagram relating sodium percentage and total concentration shows that %27 of the groundwater samples fall in the field of good to permissible, %16 of the groundwater samples fall in the field of doubtful to unsuitable and %53 of the groundwater samples fall in the field of unsuitable for irrigation. Residual sodium carbonate (RSC) has been calculated to determine the hazardous effect of carbonate and bicarbonate on the quality of water for agricultural purpose (Eaton, 1950). The classification of irrigation water according to the RSC values show that, %5 samples belongs to the good category,%16 samples belongs to the doubtful category and %79 belongs to unsuitable category. According to permeability index (PI) values, the groundwater of in the study area can be designated as class II (25–75%) indicate that the groundwater is unsuitable for irrigation excepting the two samples, which classified as class I (>75%).

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5. Conclusions Interpretation of hydrochemical analysis reveals that the groundwater in study area is very hard, fresh to brackish and alkaline in nature. The results of calculation saturation index show that the nearly all of the water samples were supersaturated with respect to carbonate minerals and undersaturated with respect to sulfate minerals. In the study area, the dominant hydrochemical facieses of groundwater is Na- Cl. Ionic concentrations, TDS, EC and water quality suggest that groundwater residence time is primarily controlled by the occurrence of different hydrochemical facies. The chemical quality of groundwater is related to the lithology of the area and the residence time of the groundwater in contact with rock materials. Assessment of water samples for drinking purposes indicated that groundwater in study area is chemically unsuitable for drinking uses. Assessment of water samples from calculation of chemical indexes indicated that groundwater in study area is chemically doubtful to unsuitable for irrigation. References

Aghazadeh, N., 2004. Hydrogeological consideration of the Harzandat plain aquifer and preparing of its mathematical model(in Persian). M.S Thesis, University of Tabrze, Iran.

APHA, 1995. Standard methods for the examination of water and wastewater, 19th ed. American Public Health Association. Washington, D.C., 1, 467 pp.

Asghari Moghaddam, A., Aghazadeh, N., 2006. Hydrogeological consideration of the Harzandat Plain aquifer of its mathematical model (in Persian). Agricultural Science, Scientific Journal of Faculty of Agriculture, university of Tabriz, Vol. 16 No.1, 73-82.

Asghari Moghaddam, A., Najib, A., 2006. Hydrogeologic characteristics of the alluvial tuff aquifer of northern Sahand Mountain slopes, Tabriz, Iran. Hydrogeology journal 14:1319-1329.

Azarbaijan Regional Water Authority, 2004. Evalution of groundwater in Harzandat plain (in Persian). Azarbaijan Regional Water Authority, Tabriz.

Coetsiers, M., Walraevens, k., 2006. Chemical characterization of the Neogene Aquifer, Belgium. Hydrogeology Journal , 14: 1556–1568.

Domenico, PA. Schwartz, FW., 1990. Physical and chemical hydrogeology. New York: John Wiley and sons.824 pp.

Drever, J.I., 1997. The Geochemistry of natural waters. New Jersey: Prentice- Hall, 436 PP.

Eaton, FM., 1950. Significance of carbonate in irrigation water. Soil Sci. 69(2), 123–133.

Freeze, R.A., Cherry, J.A., 1979. Groundwater. Prentice-Hall, Englewood Cliffs, NJ, USA.

Garrels, R., Mackenzie F., 1967. Origin of the chemical compositions of some springs and lakes. In: Ground RF (ed) Equilibrium concepts in natural water systems. American Chemical Society Publications, Washington.

Guler, C., Thyne, G.D., 2004. Hydrologic and geologic factors controlling surface and groundwater chemistry in Indian Wells –Owens Valley area, southeastern California, USA. Journal of Hydrology 285,177-198.

Kortatsi, B.K., 2007. Hydrochemical framework of groundwater in the Ankobra Basin, Ghana. Aquat. Geochem., 13: 41-74.

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Langmuir, D., 1997. Aqueous environmental geochemistry. Prentice Hall, Inc. 601 pp.

Nabavi, M.H., 1976. Preface geology of Iran (in Persian). Geology Survey Iran.

Parkhurst, D.L., Appelo, C.A.J., 1999. User’s guide to PHREEQC (ver. 2)—A computer program for speciation, batch-reaction, one-dimensional transport, and inverse geochemical calculations. USGeol. Surv. Water-Resources Invest. Rept., 99–4259.

Piper, A.M., 1944. A graphic procedure in the geochemical interpretation of water-analyses . Trans.,Am. Geophysic.Union 25,914-923.

Ragunath, HM., 1987. Groundwater. Wiley Eastern Ltd, New Delhi, pp 563.

Raju, N.J., 2006. Hydrogeochemical parameters for assessment of groundwater quality in the upper Gunjanaeru River basin,Cuddapah District, Andhara Pradesh, South India. Environmental Geology.

Richards, LA., 1954. Diagnosis and improvement of saline alkali soils: Agriculture, vol 160. Handbook 60, US Department of Agriculture, Washington DC.

Srinivasa Gowd, S., 2005. Assessment of groundwater quality for drinking and irrigation purpose: a case study of Peddavanka watershed , Anantapur District, Andhra Pradesh,India .Environmental Geology 48,702-712.

Subramani, T., Elango, L., Damodarasamy, S.R, 2005. Groundwater quality and its suitability for drinking and agricultural use in Chithar River Basin, Tamil Nadu, India. Environmental Geology 47, 1099-1110.

WHO., 1983. Guideline to drinking water quality. World Health Organization. Geneva. 186 pp.

WHO., 1989. Health Guidelines for the use of wastewater in Agriculture and Aquaculture. Report of a WHO Scientific Group-Technical Report Series 778,WHO Geneva,74 pp.

Wilcox, LV., 1955. Classification and use of irrigation water. USDA, Circular 969. Washington, DC. USA.

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Table 1 Minimum, Maximum and average values of physical and chemical parameters of groundwater samples

Average Maximum Minimum Units Parameters 7.52 3489 2300 471 11 161 78 637 479 10 490 724 7.6 55 -6.46 63.7 -0.33 -0.18 0.35 0.85 -1.71 -1.34

8.2 6220 4000 1127 50 287 205 1611 1488 60 1248 1720 19.2 79 4.5 82 0.44 0.37 1.5 2.95 -0.32 -0.5

6.8 990 653 66 1.17 54 30 115 212 0 125 325 1.2 28 -30.4 43 -1.2 -0.44 -1.08 -0.7 -3.5 -3.27

- S/cmµ mg/l mg/l mg/l mg/l mg/l mg/l mg/l mg/l mg/l mg/l - % meq/l % meq/l meq/l - - - -

pH EC TDS Na K Ca Mg Cl HCO3 CO3 SO4 TH SAR %Na RSC PI CAI,1 CAI,2 SI calcite

SI dolomite

SI gypsum

SI anhydrate

SAR: Sodium adsorption ratio RSC: Residual sodium carbonate PI: Permeability index CAI: Chloro alkaline index SI: Saturation index

EC: Electrical conductivity TDS: Total dissolved solids TH: Total hardness

Table 2 Groundwater samples of the study area exceeding the permissible limits prescribed by WHO for drinking purposes

)WHO international standard (1983,1989 Parameters Amount in groundwater samples

Maximum allowable limits

Most desirable limits

6.8-8.2 9.2 7-8.5 PH 653-4000 1500 500 TDS(mg/l) 325-1720 500 100 TH(mg/l) 66-1127 200 - Na(mg/l) 54-287 200 75 Ca(mg/l) 30-205 150 50 Mg(mg/l) 115-1611 600 200 Cl(mg/l) 125-1248 400 200 SO4(mg/l)

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Fig.3. Pie diagram of median values of major ions.

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8. Carbonate alkalie exceeds 50 %

7. Non - carbonate alkalie exceeds 50 %

9. Non one cation anion pair exceeds 50 %

Fig.4. Chemical facies of groundwater in Piper diagram.

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Methods of Coastal Conservation as viewed by Engineering Geology with examples from the Hormozgan Province.

R. Zarei Sahamieh,

Geology Department, Lorestan University [email protected]

P.Rezaee,

Geology Department, Hormozgan University

S.V. Shahrokhi,

Geology Department, Islamic Azad University, Khoram Abad Branch

Abstract Coast is an area between the sea and the land. The important types of coast are: primary and developed, sedimentary and structural, biological and glacial, sandy and stone. The most important items affecting on the coastal area are: waves, tides, winds, marine streams, manmade effects. Conservation of the coastal area is made with the aim of taking care, fixation and improvement of the situation of the area against destructive natural and artificial factors and is among important topics in the engineering geology. Methods of coastal conservation are divided in two groups: 1- structural, 2- non-structural. Conversation structures are usually in the following three groups: 1- structures perpendicular to the coast, 2- structures parallel to the coast, 3- Offshore structures. The most important conservation structures are: 1- gabions, 2- coastal walls, 3- groins, 4- revetment, 5- water breaker, 6- wedges. From the most important methods on non structural conservation, must be included to: 1- sandy fences, 2- artificial reduction, 3- plant cover and 4- management methods. The length of shorelines of the Hormozgan province extends to more than 800 km. In this scope, considering features such as types of coast, geotechnical properties of the shorelines, different development plans such as tourism, economic- social conditions, kinds and properties of waves, tides, winds and marine currents, kinds of coastal conservation methods are chosen, designed and constructed. The best examples about this case can be observed in cities such as Bandar Abbas, Bandar Jask, Islands especially Kish and Gheshm, and harbors such as Shahid Bahonar and Shahid Rajaee in the Hormozgan province. Introduction In view of civil activities, coastal areas are so important. These areas are so effective in stable development of countries enjoying from coasts. Iran has near to 3000km coastal lines, which 814km of it is placed on the Hormozgan province. This province has 14 big and small islands [1]. In this area, kinds of coastal structures with different uses are made or are making. Of course, coastal changes (natural and artificial) are very high in the banks of the Hormozgan province. The subject of this paper is considered of coastal conservation methods with especial view of this province.

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Discussion 1- Generalities Bank is an area between sea and land with relatively low dip. It consists to parts: coastal pool and embankment. The important types of coast are: primary and developed, sandy and stone, plain and orographic ,structural, biological and glacial. Erosion and sedimentation, manmade effects are factors which change banks gradually and continuously on the coastal area, are: waves, winds, marine stream and artificial factors. Effects of these items can be seen at point, local, regional, national and international scale. 2- Common properties of the Hormozgan province’s coasts This province is located at north of the Hormoz strait and in contact with the Persian Gulf and the Oman sea. This province has complex geology and composes from parts of folded Zagros, Makran and Sanandaj- Sirjan sedimentary structural units [2]. The most primary (structural, orographic, stone) coasts are concentrated on the western part and more developed (sandy, plain) coasts are concentrated on the eastern part of this province. The height of banks and tides change in order 0-20m and 0.2 - 4.3m. The main marine current is parallel to coast from the Oman sea toward the Persian gulf and direction of majority wind is between west north – east south or reversed [3]. Danger of seismicity and liquefaction in coasts of this province is high. 3- Coastal conservation methods Safeguarding of the beaches is made with the aim of taking care, fixation and improvement of the area against destructive natural and artificial factors. This subject is among important topics in the civil engineering, geology engineering coastal management. Methods of coastal conservation are divided in two groups: 1- structural, 2- non structural. Conservation structures are usually in the following three groups: 1- structures perpendicular to the coast, 2- structures parallel to the beach, 3- offshore structures. The most important conservation structures are: 1- gabions, 2- coastal wall, 3- groins, 4- revetments, 5- water breakers, 6- wedges [4]. Gabions are structures which more applied in sides of coastal rivers and low depth beaches. They are made by borrow materials (especially concrete and rock blocks). This structure is suitable for coastal rivers and beaches of areas such as Bandar Abbas, Babdare Charak, and the north of Qeshm Island. Coastal walls or retaining walls are parallel to shoreline. They reduce energy of tides, waves, marine currents and especially prevent from liquefaction of upstream sediments. This structure is seen in locations such as Bandare Lengeh and Hormoz Island. Grions are narrow structures and are made perpendicular to the beach. They have different height and are composed of wood, rock, concrete, asphalt and or steel. This structure is seen in areas such as Kish Island, Bnadare Jask. Revetments are parallel to bank and consist of rock blocks and steel plates. The kinds of them are vertical, ordinary rock mass and etc. This structure is seen at places such as Qeshm island, Kish island and Bandare Khamir. Water breakers are offshore structures. They reduce power and velocity of tides, waves, marine currents, settlement of sediments in upstream. They have different types, for example parallel to beach, convergent and inclined [5]. The best kinds of this structure are seen at Shahid Bahonar and Shahid Rajee harbors. Wedges are made for fixation of debauchers and prevention of sedimentation. They are made from different materials, such as wood, pile, shield, asphalt, gravel. This structure is seen in very points of the Hormozgan’s coasts.

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Existence of different suitable rock, especially sedimentary (such limestone), pyroclastic (tuff) and volcanic (andesite) rocks in near shore lands of this province, is a most important factors in making of types of conservation structures. The most important methods of non-structure, can be induced 1- sandy fences, 2- artificial reduction, 4- management methods. Sandy fences are made by wood or metal for fixation of coastal sediments. This method is suitable for areas such as around regions of Bandare Jask, Bandare Khamir and Bandare Maghoiyed. In artificial reduction, crushed rock, borrow materials, sand gravel from local sources are accumulated at coasts, and then are surfaced [6]. This method is very applied in areas such as Bandar Abbas, Kish island and Qeshm island. Plant covers such as halophyte, tree- brake, grass are very effective in fixation of sediments and conservation of coast in opposite of eresional factors. The Harra forest is the best example in this case, and is located at the northwest of Qeshm island. By to write and to execute suitable laws and orders can be helped to related local organizations such as harbours and navigation offices and municipalities. This process is a serious management necessity for the Hormozgan province. Conclusion In the Hormozgan province such as everywhere, considering features such as types of beaches, geotechnical properties of these areas, differential developed plans, economic- social conditions, characters of wind, wave, tide and marine currents, kinds of coastal conservation structure methods are chosen, designed and constructed [8]. The best examples about this case can be seen in long of the Hormozgan province’s shorelines. In otherwise, non structure methods are very necessary for this area, especially for future. References

[1] GITASHENACI INESTITUE, Atlas of Iran’s roads (2005), 271p.

[2] AGHANABATI, S.A, Geology of Iran, GSI (2004), 586p.

[3] REZAEE, P., et al., Coastal conservation methods in the Hormozgan province (2004), 406p.

[4] SHAPEN, Y, Marine works (translated by: K.Behnia), Tehran University Press (1990), 798p.

[5] RAHN, P.H, Engineering geology, Prentice Hall (1996), 565 p.

[6] CEDREO, A, Land use problems, planning and management in coastal zone: an introduction, Ocean & Shorelines management (1989), Vol. 12,No 5-6, p: 367- 382.

474


Qeshm Island’s Surface and Underground Waters Resources and Methods for Utilizing them.

P.Rezaee,

Geology Department, Hormozgan University [email protected]

S.V. Shahrokhi,

Geology Department, Islamic Azad University, Khoram Abad Branch

R. Zaree Sahmieh,

Geology Department, Lorestan University

Abstract The Qeshm Island with a maximum area of 1796 km2, is located at the Persian gulf, near the Hormoz strait. It is located at the extreme southeast of the Zagros sedimentary- structural unit and is a part of the folded Zagros and Bandar Abbas subzone. Varied deposits with Upper Precambrian to Quaternary age have profiles at the island surface, with much influence on the quality of surface and underground waters resources. There is no permanent river at the island. The total area of watersheds is 500 km2, and the most of which are: 1- Tourian, 2- pay posht, Deirestan, 4- Gowdrin, 5- Giahdan, and 6- Ramchah. The average annual volume of run water is 37 milions m3. The most important aquifer of the island is located at the Tourian plain. Of course, scattered and limited aquifers are at the areas such as Deirestan, Tonban, Soheili, Table, Gavarzin, Tourgan and Laft. Each year, 4-8 millions m3 of surface waters and up to 3 millions m3 of underground waters are utilized and the water balance has been negative in recent few years. The general quality of the waters being used is a medium to good level. Utilization of the aquifers in the island is effected using 387 well. At the present, there is no underground water cannel there. Storage and utilization of surface run waters is affected using 102 earth barriers and dams, 322 natural and artificial pools and water reservoirs, 366 developed natural holes. For the purpose of supplying the water required, maintaining and up grounding the quality of surface and underground waters of the island, the following and suggested: correct and optimal management of using the current resources, correction and development of the current utilization methods, exploration of new underground water resource, using sea water desalination equipments as much as possible, water transfer from the mainland, design and correct implementation of sewerage collection and treatment network. Introduction The local and time distribution of water resources in Iran is very heterogenous. In very areas of the Hormozgan province, there is an intense limitation of water resources. In this southern province of Iran, with yearly precipitation mean 200 mm and yearly evaporation average 3200 mm [1], existence of tens of salt domes, infiltration of sea water, droughts of recent years, and increase of consumption, are caused that need to suitable use and management of surface water resources increasing, especially in its island, for example the Qeshm island, which is the subject of this paper.

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Discussion 1- Geographic properties The Qeshm island with 1536 – 1796 km2 area (in view of minimum and maximum of tide and area of the Harra forest) is located at the Persian gulf and near Hormoz strait. The geographic coordinates of this island, are: 55º 20' – 56º 44' eastern longitudes and 26º 5' - 27º 10' northern latitudes. The Namakdan crest with 397m height is the most raised point of area. Moisture and warm climate, height of waves 1-5 m, sea level changes (during of tide) 0.2-4.3 m, yearly temperature average 27ºC (22-55ºC), yearly precipitation mean 175 mm, are the other common geographic characters [2]. 2- Geological characters The Qeshm island is located at the extreme southeast of the Zagros sedimentary- structural unit and is a part of the folded Zagros and Bandar Abbas subzone [3]. The most important geological structures of this island, have east- west or northeast-southwest strike. Varied deposits with Upper Precambrian to Quaternary age have profiles at the island surface, with much influence on the quality of surface and subsurface water resources. Hormoz series (Lately Precambrian- Early Cambrian) consists salt rock, gypsum, limestone, dolostone, small parts of igneous rocks. This series has out crops at shape of the Namakdan salt dome in extreme southwest of area. Saline solutions sourced from it, have very effective on reduction of quality of surface and subsurface waters, especially in the west part of this island [4]. Mishan formation (Middle-Lately Miocene) composes from marl and limestone in the area and is impermeable. Aghajari formation (Lately Miocene- Pliocene) consist sandstone, marl and siltstone. In comparison of these formations from the view of effect on reduction of quality of water resource on the area, Mishan formation is more important. Of course, parts of sandy deposits of Aghajari formation are host of restricted groundwater resources with well quality in this island. Bakhtiayri formation equivalent deposits (Pliocene- pliostocene) compose loose conglomerate, siltstone and marl. The sediments (coarse to medium), coastal and eolian sands, evaporite/ mud falts, loumashels (calcareous marine terraces) and fine grain recent sediments. Fan course- medium sediments and loumashels have well permeability and are the host of the most important groundwater resources. 3- Water resources In the Qeshm island, there is no permanent river, but there are small, short and abundant natural and artificial waterway at it’s surface. The most important watersheds are: 1- Tourian, 2- Pay posht, 3- Deirestan, 4- Gowdrin, 5- Giahdan, 6- Ramchah. They have 2-400 height, %1-12 dip and south- north or north – south strike. Annual average of total surface runoffs is 37 millions m3 (0-20 millions m3) the most important parts of this volume storage back of barriers or seepage on ground. Of course, 17 millions m3 (50-100 millions m3 in humid years) of it, yearly discharge to sea. Maximum instantaneous debit 51-161 m3/s, volume of maximum flood 36,000-1,160,000 m3, electric conductivity 2/25 dz/m and 6-20 dZ/m at back of barriers, are the other important properties of runoffs of the Qeshm island [5]. The most important aquifer is located at the Tourian plain. It has 50 km3 area and syncline structure. Average thickness of this aquifer is 37 m and composes from alluvial (fan and river) coarse – medium sediments of Quaternary age. Thickness and size of sediments, quality and quantity of subsurface water reduce in the Tourian plain from east north- north to west south-

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south. In 2006, 2,38 millions m3 discharged from the aquifer [6]. Electricity conductivity change from 1200 µZ /cm to 13800 µZ /cm, and water table is located at 4/7 – 85/4 m (mean 27/19m) bottom of surface. Of course, scattered and limited aquifers are at areas such as Table, Deirestan, Tonban, Soheili, Gavarzin, Tourgan and Laft in the other deposits of the Quaternary age. 4- Revenue methods For recovery of surface and subsurface water resources to the Qeshm island, modern methods (such as mechanical wells and earthy barriers) and conventional methods (for example natural pools and holes) are used. Each year, 4-8 millions m3 of surface waters and up to 3 millions m3 of subsurface waters are utilized. Utilization of the aquifers in the area is effected using 358 wells which 231 of them are placed on Tourian plain with mean discharge 3/17 litr/s. Storages and utilization of surface run offs is effected using 102 earth barriers and dams, 322 natural and artificial pools and water reservoirs, 366 developed natural holes. Volume of capital storage waters in back of earth barrier and dams are 25/910/800m3 [7]. There is no active qanat in the Qeshm island. Conclusion The water balance has been negative in recent few years on Qheshm island and reached, 2/000/000 m3 in some years. For the purpose of supplying the water required, maintaining and upgrading the quality of surface and underground waters of this area, especially for future years, the following and suggested: correct and optimal management of using the current resources, correction and development of the current utilization methods, exploration of new underground water resources, using sea water desalination equipments as possible (especially, local and solar water desalinators), water transfer from the mainland, design and correct implementation of sewerage collection and treatment network. References

[1] AMRI KAZEMI. A.R, The geological atlas of Qeshm island, GSI (2005), 113p.

[2] HAGHIPOUR, A., Geology of the Qeshm area, Qeshm free area (2005), 5p.

[3] AGHANABATI. S.A., Geology of Iran, GSI (2004), 586p.

[4] TOOS AAB ADVISER ENGINEERING CO, Project of water securing in the Qheshm island (subsurface), Vol 4 (1999), 33p

[5] QHESHM FREE AREA, Surface water resources of the Qeshm island and their exploration, Vol 9 (1998), 104p.

[6] TOOS AAB ADVISER ENGINEERING CO, Project of water securing in the Qeshm island (conclusion and planning), Vol 12 (1999), 121p.

[7] KAMAND AAB ADVISER ENGINEERING CO, Statical report of the Qeshm area (2006), 124p.

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Geotechnical Properties of the Quaternary Calcareous marine terraces of the Qeshm island

P. Rezaee

Geology Department, Hormozgan University [email protected]

A.R. Rasekhi

Civil Engineering Department, Islamic Azad University, Qeshm Branch

Abstract The Qeshm island with a maximum of 1796 km2 is located at the Persian gulf, near the Hormoz strait. It is located at the southeast of the Zagros sedimentary structural unit. Varied deposits with Upper Precambrian to Quaternary age have outcrops at the island's surface. The Quaternary calcareous marine terraces are located from bank until latitude of 220m in different parts of the Qeshm island. These deposits are composed from types of limestone. Geotechnical experiments achieved on 180 samples from 30 holes drilled on these deposits. The most important results are: porosity: %10.7-20.2, Loss of weight: %0-3, Percentage of abrasion (Los Angles method): %49-100, Percentage of water absorption: %2.4-26, Dry compressive strength: 21-87 kg/cm2, Moisture compressive strength: 4-50 kg/cm2, Index of R.Q.D: %23-69, Index of CR: %43-95, Vertical Force: 3-6 kN, Vertical stress: 1.04-2.09 MPa, Dry density: 1.25-2.15 gr/cm2, Apparent specific gravity: 2.118-2.359 kN/m2, True specific gravity: 1.790-2.107 kN/m2, Effective shear stress: a) ultimate: 0.35-0.87 MPa, b) residual: 0-0.7 MPa, Resistivity coefficients: a) ultimate: Cu = 0-0.82 kg/cm2, Øu: 0-23o, b) residual: Cr: 1.2 kg/cm2, Ør: 0-19o. These information show that the deposits have low to moderate strength and are moderate dense. These geotechnical properties are caused until civil applications of these rocks in the Qeshm island are very different, but must be precaution. Introduction In the Qeshm island, there are 28 calcareous marine terraces of the Quaternary age. These rocks have abundant applies in civil activities on the area. So, to recognize of geotechnical properties of these deposits is very important. This affair, is the subject of under paper. Discussion 1- Geographic characters: The Qeshm island with 1536 - 1796 km2 area (in view of maximum and minimum of tide, and area of the Harra forest), is located at the Persian gulf and near the Hormoz strait. This island has below geographic coordinates: 55o 20'-56o 44' eastern longitudes and 26o 5'-27o 10' northern latitudes. The Namakdon crest with 397m height is the most raised point of the Qeshm island. From the most important geographic properties of this island, can be direct to below cases: moisture and warm climate, height of waves 1-5m, sea level changes (during of tide) 0.2-4.3m, mean of year temperature 27oc (22-50oc), average of year precipitation 175mm [1].

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2- Geological properties The Qeshm island is located at the extreme southeast of the Zagros sedimentary-structural unit and is a part of the folded Zagros and Bandar Abbas subzone. Varies deposits with Upper Precambrian to Quaternary age have profiles at the island surface. Hormoz series (Lately Precambrian-Early Cambrian) which consists of salt rock, gypsum and parts of limestone, dolostone, sandstone, and igneous rocks. Mishan formation (Middle-Lately Miocene) that compose from limestone and marl. Aghajari formation (Lately Miocene-Pliocene) which consists of sandstone, marl and siltstone. Bakhtiyari formation equivalent deposits that compose of loose conglomerate, marl and siltstone. Quaternary deposits of the Qeshm island are very different: marine terraces, alluvial sediments, coastal and eolian sands, evaporite/mud sediments, fine grain recent deposits [2]. The important geological structures of this island, have east-west or eastnorth-westnorth strike. Relatively danger of earthquake in the area is high and minimum of base design acceleration is 0.35g[3]. 3- Quaternary calcareous marine terraces The age of this deposits is Pleistocene to Holocene. There are 28 Quaternary calcareous marine terraces in the Qeshm island from near of beach to 220m height [2]. They overlay older deposits with a erosional unconformity. These deposits have a low dip to sea, relatively flat shape, and 10m maximum thickness. They place especially near and along coasts of this island. These terraces are composed from fine to coarse grain limestones and are rich from bioclasts, example: bivalve, coral, red algae, echinoderm and bryozoae until 70%. These rocks that are named Loumashel commonly, settle at classes of mudstone, bioclast wackstone, bioclast packstone and rudstone. They have very low quartz, feldspar and iron oxides. 4- Geotechnical properties of Quaternary calcareous marine terraces For study of these characters, 30 hole drilled in the terraces at places how Suza, Basaidu, Dulab, Mesen, extreme east of the Qeshm island and 180 samples took from these deposits. The different geotechnical field and laboratory tests on these holes and samples, show that the Quaternary calcareous marine terraces have below properties: 1-RQD (rock quality designation) index: %23-69.2-CD (recovery percentage) index: %43-95,3 Vertical force (Pn): 3-6 kN, 4-Vertical stress (6n): 1.04-2.09 MPa, 5-Dry density: 1.25-2.15 gr/cm3, 6- porosity (n): %10.7-20.2,7-Loss of weight: % 0-3.8-Percentage of abrasion (Los Angles method): %49-100, 9-Percentage of water absorption: %2.4-26, 10-Dry compressive strength 21-87 kg/cm2, 11-Moisture compressive strength: 4-50 kg/cm2, 12-Apparent specific gravity: 2.118-2.359 kN/m2, 13-True specific gravity: 1.790-2.107 kN/m2, 14-Effective shear stress: a) ultimate: 0.35-0.87 MPa, b) residual: 0-0.7 MPa, 15-Resistivity coefficients: a) ultimate: Cu: 0-0.82 kg/cm2, Øu: 0-23o, b) residual: Cr: 0-1.2 kg/cm2, Ør: 0-19o. Conclusion The experimental information and correlated them with geotechnical references about these, show that the Quaternary calcareous marine terraces have low to moderate strength and are moderately dense. These rocks are suitable and have very applies in make of small wave breakers, coastal walls and revetments (especially in the north coasts), borrow materials (for

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different structures such as roads, barriers and …) and pure lime in the Qeshm. Of course, these applications must be precaution. References

[1] AMRI KAZEMI, A.R, The geological atlas of Qeshm island, GSI (2005), 113p.

[2] HAGHIPOUR, A, Geology of the Qeshm area, Qeshm free area (2005), 5p.

[3] VISEH, S., KHODABANDEH, N., Exploration and quality appointment of Qeshm island's local materials, House and building institute (2003), 156p.

[4] HAGHIPOUR, A, Geological researches and mining explorations of Qeshm area, Ministry of metals and mines (1995), 523p.

480


Investigation of Engineering Geology characterization of Khersan 3 dam site.

R. Dadkhah1, R. Ajalloeian2, Z. Hoseeinmizaei3

1 PhD. Student, Ferdowsi University of Mashhad, Mashhad, Iran

2 Asst. Prof., Dept. of Geology, Faculty of Science, Isfahan University, Isfahan, Iran,

3 M.Sc., Dept. of Geology, Faculty of Science, Hamedan University, Isfahan, Iran

Abstract This paper discusses the results of engineering geological investigation and geotechnical studies carry out at the propose Khersan3 dam site. The dam will be built on Khersan river, located in 50 km of west of Lordegan city in west of Iran. The Khersan dam has 370 m length crest, 175 m maximum height and 777.505*106 m3 total storage capacity. The dam is mainly founded on sedimentary rocks of the Tertiary age and on Quaternary deposits. Geotechnical information obtains from both of field and laboratory study. Field study includes engineering geological mapping, surface discontinuity mapping, drilling borehole and sampling for laboratory testing. Samples obtain from drilling have been tested in the laboratory, included of uniaxial, triaxial and tensile strength tests and deformation parameters, unit weight and porosity. We can classification rock masses of dam according to RMR, Q and GSI system. Detailed of geological and geotechnical study (i.e. scan-line survey, discontinuity measurements, various laboratory, in-situ tests, kinematics analyses and etc.) was carrying out in the project area to determine the engineer in geological characteristics of the rock masses. In this study, using Geological Strength System (GSI) and the Hoek-Brown equation for rock mass classify properties to obtain rock mass strength parameters and elasticity modulus. 1. Introduction Rocks have been classified on the basis of their origin, mineralogical composition, void index, fracture/joint intensity, joint inclination, flow rate of water, velocity of propagation of shock wave, weathering, colour or grain size. When rocks and rock masses are classified for geotechnical purposes, they need to be classified on the basis of strength and/or modulus to give an indication of their stability and/or deformability. The purpose of this study is to investigate the Engineering geological characteristics of the rock Material and rock mass a khersan3 dam. The Khersan3 dam will be situated on the Khersan River, 50 km south-west of Lordegan in the east part Mountain Zakrose of Iran (Fig. 1).It will be used for flow control and water storage for product energy projects. The design of Khersan3 Dam is under the direction of General Directorate of the Ministry of Energy, Iran. This paper explains engineering geological assessment for safe design of the proposed khersan3 Dam. These geotechnical Investigations (scan-line survey, discontinuity measurements, various laboratory and in-situ tests, kinematical analyses, etc.) have been carried out at the project site and in the laboratory. Various laboratory and in-situ tests were performed to assess the characteristics of rock masses. Detailed discontinuity surveying was also carried out. In the study, rock mass properties were classified using RMR (Bieniawski, 1989), Q (Barton et al., 1974) and GSI (Hoek and Brown, 1997) was used to obtain rock mass strength parameters.

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2. Geological setting Geological factors play a major role in designing and constructing a dam. Of the various natural factors that influence the design of dams, none are more important than the geological ones. Not only do they control the character of formations, but they also govern the material available for construction. There exist numerous examples of projects where the conditions of the foundation were not sufficiently known and the cost of construction and treatment greatly exceeded the original budget (Ichikawa, 1999). The Khersan3 Dam is located on sedimentary rocks of the Tercier Age and on Quaternary deposits. 3-Engineering geological investigations or site investigation The preliminary site investigations were carried out start on the 1996. Engineering geological investigations and rock mechanics studies mainly include discontinuity surveying, core drilling, in-situ is testing. 3-1-Mass properties The engineering geological properties of the rock masses at the site have been assessed in accordance with the working partly and the International Society for Rock Mechanics (ISRM) Suggested method (ISRM, 1978). 3-2-Discontinuity surveying Discontinuities surveys consisted of orientation, aperture, roughness, persistence, infilling and spacing was determined at the site by exposure logging in accordance to ISRM (1981). A total of 558 discontinuities, 258on the right bank and 300 on the left bank, have been measured. The basic orientation data were analyzed using a computer program based on equal-area stereographic projection namely DIPS 5.0 (Diederichs and Hoek, 1989) in order to determine the number of dominant discontinuity sets. Three dominant discontinuity sets and bedding are distinguished on the right bank (Fig. 2) that including: (dip direction/dip) J1:65/275; J2:35/235; J3:45/180. Four dominant discontinuity sets and also are determined on the left bank (Fig. 3) that including: (dip direction/dip) J1:73/300; J2:80/030; J3:30/140; J4:45/260. Table 1 shows quantitative descriptions and statistical distributions of discontinuities of rock units at the dam site according to ISRM (1981). 3-3-Drilling In order to verify foundation conditions and to obtain rock samples for laboratory testing, borings were made at this site in د stages. Based on these studies, 47 boreholes, totaling چن5303.7 m, were drilled on the dam site (Fig. 4). Tables 2 show the Rock Quality Designation (RQD) of the right abutment, left abutment, riverbed and boreholes, respectively. 4-Laboratory tests Detailed laboratory studies were performed on the specimens prepared from blocks, samples and core specimens of NX-size; (54.7 mm) determine the geotechnical parameters of the intact rock. The tests on NX size specimens were carried out according to the procedures recommended by ISRM (1981) suggested methods Mechanic tests, the Uniaxial Compressive Strength (UCS) test, density, absorption test, deformability and porosity tests were conducted according to ISRM (1981) standards. The deformability parameters, Poison’s` ratio (m) and modulus of elasticity (Ei) were also obtained from deformability test. The results are given in Table 4.

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5-Rock mass classifications of rock units For the qualification of the rock mass the khersan3 dam, RMR and Q rock mass classification systems and GSI system were used. These systems have been used for a long time and evolved due to the requirement of modifications for the different case studies but there are still doubts and confusions on the applications. A brief explanation of RMR and Q systems and their evolutions is therefore necessary. Bieniawski (1974) has initially developed rock mass rating (RMR) system. He has developed this system on the basis of experiences in tunnel projects from South Africa. Since then, this classification system has undergone significant changes. These changes are mostly on the ratings given to ground water, joint condition and joint spacing. In order to apply this system for the classification of rock mass, the uniaxial compressive strength of intact rock, rock quality designation, RQD, joint spacing, joint condition, joint orientation and ground water conditions have to be known. Barton et al. (1974) have developed Q rock mass quality system. Q system is also known as NGI rock mass classification (Norwegian Technical Institute). This system is defined by the function of joint sets, Jn, discontinuity roughness, Jr, joint alteration, Ja, water pressure, Jw, stress reduction factor, SRF and RQD. Recently, Barton (2002) has compiled the system again and has made some changes on the support recommendations. He has also included the strength factor of the rock material in the system. Rock mass classifications can serve as a powerful design tool in Dams construction, showed how to estimate the compressive strength of a rock mass based on the (m) and (s) criteria. Hoek et al. (1995) have expressed the compressive strength of rock masses with an equivalent set of cohesion and friction parameters for given Hoek–Brown values. The geotechnical properties of the rock units comprising the Dam site were assessed by using three empirical rock mass classification systems, namely RMR method, Q method and GSI (Geological Strength Index). The Geological Strength Index (GSI), introduced by Hoek (1994), Hoek et al. (1995) and Hoek et al. (1998) provides a system for estimating the reduction in rock mass strength for different geological conditions as identified by field observations. 5.1. Results of rock mass classification systems at dam site rock units In order to overcome some uncertainties of these classification systems, a range of rock mass values was estimated rather than just a single value.The RMR (Bieniawski, 1989) classification of the Dam site rock units is shown in Table 5. As shown in this table, the rock units are classified as medium rock quality (class III). The Asmary unit at left bank is classified as medium rock masses (RMR=56). The Asmary unit at right bank and riverbed is classified as fair rock (RMR=59). The Q (Barton et al., 1974) classification of the dam site rock units is shown in Table 6. As shown in this table, the rock units are classified as medium rock quality (class III). The Asmary unit at left bank is classified as medium rock masses (Q=6.79). The Asmary unit at right bank is classified as fair rock (Q=7). In the study, furthermore RMR and Q methods, rock mass properties were classified using the GSI system. This system was evaluated by (Hoek et al., 1998). These groups are shown in Table 7. Asmary unit at right bank (crystalline to microcrystalline limestone) is classified as Blocky to Very Blocky (GSI=53-64). Asmary unit at left bank (crystalline limestone to marly limestone) is classified as Blocky to Very Blocky (GSI=49-58).

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6. Rock mass strength estimation Singh (1993) proposed the following relationship to be an approximate estimate to the value of the rock mass compressive strength based on the rock mass Q and rock density γ (kN/m3), in Bhasin and Grimstad (1996).

)(7.0 31

MPaQm γσ = Too the rock mass strength parameters such as, Hoek–Brown constants, modulus of elasticity and uniaxial compressive strength, are essential need in the preliminary stages of dam design. In this study, Hoek–Brown strength criterion was used for estimation of the rock mass strength parameters. To estimate, the parameters related to Hoek–Brown criterion, which represent the rock mass, the test results of the intact rock specimen were used in conjunction with GSI values. The generalized empirical failure criterion is as follows (Hoek et al., 2002)

a

cibci sm ⎟⎟

⎠

⎞⎜⎜⎝

⎛+

′+′=′

σσσσσ 3

31

Where σ'1 and σ'3 are the major and minor effective principal stresses at failure σci is the

uniaxial compressive strength of the intact rock material and mb is a reduced value of the material constant mi and is given by

⎟⎠⎞

⎜⎝⎛

−−

=D

GSImm ib 1428100exp

Intact rock constant (mi) was found from Table 8.3 of Hoek et al. (1995). s and a are constants for the rock mass given by the following relationships:

⎟⎠⎞

⎜⎝⎛

−−

=D

GSIs39100exp ⎟

⎠⎞⎜

⎝⎛ −+=

−−3

2015

61

21 eea

GSI

D is a factor which depends upon the degree of disturbance to which the rock mass has been subjected by blast damage and stress relaxation. It varies from 0 for undisturbed in situ rock masses to 1 for very disturbed rock masses (Hoek et al., 2002). Also the in-situ deformation modulus of rock masses (Em) can be obtained by using the GSI value in the formula below (Hoek et al., 2002).

( ) ⎟⎠⎞⎜

⎝⎛ −

⎟⎠⎞

⎜⎝⎛ −= 40

10

10.1002

1)(GSI

cim

DGPaE σ

The rock mass constants, uniaxial compression strength and the in-situ deformation modulus of each rock units are presented in Table 8. 7-Conclusions and recommendations Based on the information collected at site and the analysis carried out, the Both theoretical and empirical solutions showed that limestone Asmary unit creates no problem since the rock mass strength greater than tangential stress concentration. When the results from different methods based on parameters found by using GSI are examined, it is seen that GSI gives consistent results irrespective of the evaluation method. Khersan3 Dam will be built on sedimentary rocks which consist of microcrystalline limestone and marly limestone of the tercier Age. Quantitative description of discontinuities was performed at the site by exposure logging in accordance with ISRM (1981). This high permeability is one of main geological engineering problems of the Khersan3 Dam. Therefore, improving the rock units by injection of cement is recommended for reduction of seepage flow through the foundation and left bank of the dam.

484


Khersan3 Dam, concrete dam will be located on the sedimentary rocks. These rocks indicate fair rock mass quality. Engineering geological investigations, test results and computations indicate that Khersan3 concrete dam can be safely constructed on the proposed site. The regional and local engineering geology have played a major role in the planning, design, construction and preference of the Khersan3 Dam. This paper assesses the engineering geological characteristics of the rock units and rock mass and suggests appropriate recommendation and improving techniques at Khersan3 dam site. A detailed engineering geological study (scan-line survey, discontinuity measurements, core drilling, etc.) was carried out in the project. The dam site and reservoir will be situated in an area underlain by Upper Cretaceous sediments, and Quaternary deposits. The rock masses of the dam site were classified as fair quality rock mass. The results of the Permeability testing showed that permeability in the rock units of the dam foundation and left bank are medium to high. This high permeability is one of main geological engineering problems of the Khersan3 Dam. Therefore, improving the rock units by injection of cement is necessary for permeable zones to prevent leakage through the foundation and left bank of the dam. References

1-Barton, N., Loset, Lien, R. and Lunde, J. 1980. Application of the Q-system in design decisions. In Subsurface spsce, (ed. M. Bergman) 2, 553-561. New York: Pergman.

2-Bieniawski, Z.T. 1989. Engineering Rock Mass Classifications. Wiley, New York. Pp.251.

3-Diederichs, M.S., Hoek, E., 1989. DIPS 2.2. Advanced VersionComputer Programme, Rock Engineering Group, Department of Civil Engineering, University of Toronto.

4-Grimstad, E., Barton, N., 1993. Updating the Q-System for NMT. In: Kompen, Opsahl, Berg (Eds.), Proc. Int. Symp. on Sprayed Concrete-Modern Use of Wet Mix Sprayed Concrete for Underground

Support, Fagernes, Oslo: Norwegian Concrete Assn.

5-Hoek, E. and Brown, E.T. 1997. Practical estimates or rock mass strength. Intnl. J. Rock Mech. & Mining Sci. & Geomechanics Abstracts. 34 (8), 1165-1186.

6-Hoek, E., Kaiser, P.K., Bawden, W.F., 1995. Support of Underground Excavations in Hard Rock. Balkema, Rotterdam,

7-Hoek, E., Carranza-Torres, C.T., and Corkum, B. (2002), Hoek-Brown failure criterion –2002 edition. Proc. North American Rock Mechanics Society meeting in Toronto in July.

8-Hoek, E., Marinos, P. and Benissi, M. 1998. Applicability of the Geological Strength Index (GSI) classification for very weak and sheared rock masses. The case of the Athens Schist Formation. Bull. Engg. Geol. Env. 57(2), 151-160.

9-Ichikawa, K., 1999. Geological investigation of dams. Proc. of 2nd Asian Symposium on Engineering Geology and the Environment. Malaysian National Group, Bangi, Malaysia, 1-44–1-57.

10-ISRM, 1981. Suggested Methods for the Quantitative Description of Discontinuities in Rock Masses. Rock Characterization, Testing and Monitoring, London. Pergamon, Oxford, 221 pp.

11-Sari, D., Pasamehmetoglu, A.G., 2003. Proposed support design, Kaletepe tunnel, Turkey, engineering geology, article in press

485


Table 1:Quantitative descriptions and statistical distributions of discontinuities of Right and Left bank at the Khersan3 Dam site.

Range Description Distribution (%) Right bank Left bank J1 J2 J3 J1 J2 J2 J3

Spacing (mm)

20> Extremely close - - - - - - - 20-60 Very close - - - - - - - 60-200 Close 35 16 12 - - - - 200-600 Moderate 35 24 18 40 35 - - 600-2000 Widely 20 60 38 40 30 25 50 2000< Very widely 10 - 32 20 35 75 50

Aperture (mm)

0.25-0.5 Partly open 20 20 15 - 10 - - 0.5-2.5 Open 10 20 17 10 20 10 5 2.5-10 Moderately wide 70 60 68 90 70 90 95

Persistence (m)

0.25-0.5 Partly open 10 10 10 10 30 50 5 0.5-10 Moderately 90 90 90 90 70 50

Description Right bank Left bank J1 J2 J3 J1 J2 J3 J4

filling

Clay * - - * * - * Calcite - - * - - - - Hematite * * * * - * * Limonite * * * * - * *

Water Condition Dry * * * - * * * Wet - - - * - - -

Roughness Rough * * * * * * * Smooth - - - - - - -

Table 2: Rock Quality Designation (RQD) of the abutment site boreholes.

Borehole NO. Upper Asmary (m) RQD% Lower Asmary (m) RQD%

Right Bank

KT-15 0-48.60 56 48.60-90 68 KT-18 0-70 74 - - KT-23 0-134.35 62 134.35-150 80

Ave 65 74

Dam axis KT-33 - - 6-210 63 KT-35 - - 6-100 58

Ave - 60

Left Bank KT-24 0-92 58 92-105 87 KT-36 0-44.45 56 44.45-150 69

Ave 58 78

90-100 75-90 50-75 25-50 0-25 R.Q.D%

Very Good Good Medium Bad Very Bad Rock Quality Designation

486


Table 4: Laboratory testing results of Asmary rocks at Khersan3 Dam R

ock

unit

Bor

ehol

e N

O.

Den

sity

gr/

cm3

Abs

orpt

ion

%

Poro

sity

%

Uni

axia

lCom

pres

sive

Str

engt

h (M

pa)

Mod

ulus

of e

last

icity

(G

Pa)

Pois

son

Rat

io

Coh

esio

n (M

Pa)

Inte

rnal

fric

tion

angl

e (φ

)

Upper Asmary

KT-15 2..66 0.94 2.18 67.99 40.17 0.20 49.98 53.19 KT-18 2.61 2.01 4.92 73.18 43.25 0.19 50.49 57.75 KT-23 2.63 1.57 4.03 118.26 37.51 0.21 39.20 60.20 KT-24 2.51 4.31 11.30 68.78 23.35 0.17 24.20 55.30 KT-36 2.48 5.02 12.41 62.73 19.81 0.20 21.80 49.99

Ave 2.57 2.77 7.52 78.02 32.81 0.19 37.13 55.28

Lower Asmary

KT-15 2.60 1.91 3.23 58.47 41.25 0.2 13.2 27 KT-23 2.53 2.58 6.37 36.89 34.67 0.25 11.50 18.98 KT-33 2.61 2.1 5.98 102.18 32.23 0.17 15.30 31.1 KT-35 2.62 2.01 4.19 48.37 26.30 0.22 12.81 19.1 KT-24 2.62 1.48 2.72 94.57 43.83 0.25 14.39 29.20 KT-36 2.59 0.98 1.99 120.72 40.4 0.21 16.32 21.23

Ave 2.59 1.69 4.08 76.87 36.45 0.21 13.92 24.43

Table 5: The RMR classification of the dam site rock units

Parameters

Location

Right bank Left bank

Value Rating Value Rating UCS (MPa) 78.02 7 76.87 7 RQD 70 13 68 13 Spacing (m) 0.6-2 and 2< 18 0.2-2 12

Condition of discontinuities

Persistence (m) 0.25-10 4 0.25-10 4 Aperture (mm) 0.25-10 0 0.25-10 0 Roughness Rough 5 Rough 5 Filling Smooth filling < 5 mm 0 Smooth filling < 5 mm 0 Weathering Low weathered 5 Low weathered 5

Groundwater dry 15 Dry and wet 12 Discontinuity orientation Fair -5 Fair -5 RMR 59 56

Table 6: The Q classification of the dam site rock units

Parameters

Location


Value Rating Value Rating RQD 70 70 68 68

Joint set number ( Jn) four joint sets plus random

15 four joint sets plus random

15

Joint roughness number ( Jr) Rough and irregular, undulating

3 Rough and irregular, undulating

3

Joint alteration number ( Ja) Slightly altered joint 2 Slightly altered joint 2

Joint water reduction factor ( Jw) Dry excavation or 1.0 Dry excavation or 1.0

Stress reduction factor (SRF) Medium stress 1 Medium stress 1

Q 7 6.79

487


Table 7: Field of GSI classification of distinct rock mass types encountered in the Khersan3 dam.

Table 8: Geotechnical parameter of the dam site rock units

Parameter

Location


Min Max Ave Min Max Ave

Intact Uniaxial Compressive Strength (MPa) 62.73 118.26 78.02 36.89 120.72 70.87 mi 10 14 12 8 12 10

material constants mb 1.866 3.87 2.678 1.294 2.678 1.866 s 0.0054 0.0183 0.0094 0.0035 0.0094 0.0054 a 0.505 0.502 0.503 0.506 0.503 0.505

Upper Limit of Confining Stress (MPa)

4.027 4.419 4.179 3.772 4.347 4.071

Cohesion (MPa) 1.434 2.869 1.868 0.973 2.377 1.523 Friction Angle (Deg) 42.63 52.45 47.05 35.63 50.02 43.52

Roc

k M

ass

Para

met

er

(MPa

)

Tensile Strength -0.1813 -0.5596 -0.274 -0.0986 -0.424 -0.205 Uniaxial Compressive Strength

4.497 15.869 7.451 2.096 11.529 5.081

Global Strength 11.684 32.857 17.662 5.661 27.328 13.2 Modulus of Deformation 9413.21 22387.21 13999.19 5733.96 15848.9 10005.3

GSI 53 64 58 49 58 53

Fig. 1. Location map of the Khersan 3 Dam site.

Right bank

Left bank

488


Fig.2: Dominant joint sets on right bank of the Kersan3 Dam site.

Fig.3: Dominant joint sets on Left bank of the Kersan3 Dam site.

489


Investigation the impact of flood spreading project on groundwater level

Reza Ghazavi1, Abbasali Vali1, Reza Ghasemi

1Assistant professor, Department of range and watershed management, Shiraz University, Iran

Abstract Percolation of flood waters into the bed and banks of ephemeral streams provides one of the key mechanisms responsible for transmission loss.The purpose of this paper is to delineate and explain variations of groundwater quality and groundwater discharge in relation to flood spreading. A total of 10 dug wells were sampled from the study area. Groundwater level was measured after any floods spreading in 10days interval for 3 month and also in the day that flood evevent was occurred. Depth of study dug wells range from 40 to 65 m below ground level in the study period . Our results indicate that the floodwater spreading can influences groundwater level. These results shows that floods water can interact with the neighboring aquifer during flood spreading projection. Stream water levels that rise in response to runoff may result in lateral water flow into the neighboring floodplain. Key words: Flood spreading projection, Groundwater quality, Groundwater level Introduction Floodplain associated with streams is of particular importance because of the significance of their cumulative impacts on downstream water quality and groundwater level. Knowledge of the exchange between groundwater and surface water bodies is essential for evaluating the role of riparian floodplain processes on water quality and groundwater level variation (Angier et al., 2005; Rassam et al., 2005). In the arid and semi-arid areas, rainfall distribution is bimodal and highly skewed with the highest, rainfall amounts and intensity, being received in the winter and spring. The annual evaporation is high, and exceeds annual rainfall for most part of the year (Stephen et al, 2008).The high intensity and short duration convective of rainfall cause the extensive overland flow. High evapotranspiration and low rainfall in arid area is the most limiting factor to socioeconomic development in the river basin (Kithinji and Liniger 1991). Excess evapotranspiration and low precipitation during subsequent dry seasons has been conduced to increased groundwater abstraction for enhance crop production (Stephen et al, 2008). Ground-water abstraction increases from 20% in the wet season to over 70% in the dry season (Aeschbacher et al. 2005). The water demand has been increasing continuously due to population growth, and cause farmers immigration to adjacent high agricultural potential .Subsequently, immigration has resulted to land use change in the lower zones from natural vegetation to small-scale agriculture, which have led to increased ground-water abstraction. Hedelin (2007) and Xia et al. (2007) indicated that pressure on the world’s water resources is increasing, restraining social and economic development in many countries, and threatening ecological values in others. Moreover, in arid and semiarid area, bimodal and highly rainfall leads to infrequent flood that can be extremely damaging (Kowsar, 1992). To reduce the impacts of persistent intra-seasonal drought and also to reduce flood damaging, rainwater storage is a prerequisite in arid and semiarid area that keeps water far from

490


evapotranspiration, increase groundwater level and decrease flood hazards (Kowsar 1992, Rejani 2008). There are several techniques for implementation of water harvesting based on farming and watershed management policy.Flood spreading is one of the suitable methods for flood management and water harvesting that increase the ground-water recharge (Dhruva et al.,1990). Flood spreading and management would not only reduce negative environmental effects such as soil erosion through reduced runoff, but also reduce water pressure and direct stream flow abstractions during the dry seasons (Al-Qudah,2009). Floodplain associated with low-order streams are of particular importance because of the significance of their cumulative impacts on downstream water quality (Angier et al., 2005; Rassam et al., 2005). Knowledge of the exchange between ground-water and surface water bodies is essential for evaluating the role of riparian floodplain processes on water quality and groundwater level variation. Flood-water directly can influences groundwater flow level in the area with high groundwater level. Surface water may interact with the neighbouring aquifer during flood events. Stream water levels that rise in response to runoff may result in lateral water flow into the neighbouring floodplain. In the area with high ground-water level, this water is slowly released back to the stream when the stream water level drops (Todd, 1955., Kondolf et al., 1987., Peterjohn and Correll, 1984). In lowland rivers, water is continously exchanged between the river and its floodpalin through groundwater.In arid and semiaride regions, modification to this exchange (through flood spreading, dams,etc) have been implicated in ground-water level and ground-water chimical properties of river and floodplain.However, the impact of modifying the groundwater-surface water regime on groundwater level and groundwater quality is not as well know.The purpose of this paper is to delineate and explain variations in groundwater rechaarge and groundwater quality along a ephemeral stream that has been modified by canalizations. Study site The study site named Hajitahere (latitudes 28°52' 28" N, longitudes 54°41'30" E) located in a catchment 25 km west of Darab, Fars, Iran. Darab has been located in arid and semi-arid zone with hot and dry summer and cold and dry winter. The main study area, which FSP located there, has 2.2 km long and 1.5 km wide. General slope in the flood plain is between 1- 5 percent. Data monitoring In the flood projection area, some dikes have been made on isoaltitude lines. There are some overflows for leading extra floodwater to the other dikes. The distance of overflow spacing is about 50m. Immediately after each dike, a settlement basin (spreading channel) was made for water relaxation and suitable time for more penetration. Water spreading designed as the water was transported by transition channel to the first diffusion channel and separated behind of the first dike . After inflowing of water to this basin, water will reach to a particular level (0.2 m) for spreading inside the FSP region. When the level of water behind of the first dike reaches to a level that all soil surfaces were irrigated, water will be transferred to the second diffusion channel by the overflows. Hajitahere is an ephemeral river that its flow (about 10

491


yearly peak flows) distributes on FSP area. The mean yearly flood water of this river is about 1 million m3. A total of 10 dug wells located in downslope of FSP area were sampled from the study area. Figure (1) indicat the schematic of study area and location of wells. Studied welles were located in different distance from FSP area and also in different distance from main river.Groundwater level was measured after any floods spreading in 10 days interval for 3 month and also in the day of floods events .Based on geround-water mesurement, monthly change in groun-water level was calculated and compared . Results The study area has a mean annual rainfall of 290 mm of which 85 % was occurred in the autumn–winter period, 13% in the spring and only 2% in the summer (Figure 1). The mean annual air temperature is 22° C, ranging from 9.6° C in January to 34° C in July.Ground-water level was maximum in the summer and increased with increasing of rainfall. Maximum ground-water level was observed in February. In the wet season,with increasing of rainfall , ground-water obstraction for irrigation decreased and in the same time flood storage increased , consequently ground-water level from soil surface decreased (Figure 2) . Ground-water level dropped continuously throughout the study periods. The means of ground-water level was about 45m in hydrological years 2004-2005 and increased to 65m in 2008-2009 . Because of the sharp decreas of rainfall and during studied years , ground-water recharge by surface water has been decreased (Figure 3a). Mean of yearly rainfall was 375mm in 2004-2005 hydrological years and decreased to 147, 275, 87.5, and 175mm respectivly for 2005-2006 to 2008-2009 hydrological years.Morevore,irrigation water requirements were increased with decreasing of rainfall and so more wells were dug and ground-water abstraction extracted each year. Due to imbalance between extraction and supply, the groundwater level dropped at an annual rate of 3 to 5 m. The water table depth from soil surface was about 42m, 45m, 42m, 48m and 61m respectively for 5 hydrological study years. Table (1) shows ground-water level change for 10 wells located at different distance of FSP area for 3 month interval after flood evevents compared to ground-water level in the days that flood spreading area was irrigiated by flood.Results shows that ground-water level rise after flood spreading in all wells. Recharge of ground-water was maximum in 2th month after flood events (figure 4a shows the results of 5 studied wells) and decrease with increasing distance from FSP area (figure 4b). No scignificant different was observed due to distance of studied wells from main rivers(figure 4c) Discusion Ground-water level decreased continusely during 5 hydrological studiedyears.The Increasing of ground-water level from soil surface in the studied basin is alarming and urgent attention is required to reverse the trend. The cumulative effect of water abstractions in this area is reflected by dropping of ground-water level. The case study, which is representative of water crisis in other sub-basins in arid and semi arid area, was used to demonstrate this scenario. The water crisis is aggravated by poor water governance system, which has led to over abstraction of irrigation water and low water use efficiency. This has led to high proportions of unauthorized water abstractions.Results show that ground-water level can affected by

492


groud-water spreading in the upstream of wells. The results show that flood storage can provide a feasible water management option, which may reduce the demand on ground-water abstraction during dry and wet seasons. This means that excess runoff and flood flows would be stored and used for ground-water recharge during wet period of years. Flood storage ensures water availability throughout the dry season. Another positive impact of flood storage is runoff reduction, which would reduce land degradation related to soil erosion. Soil erosion depletes agricultural lands of fertile top soil and also leads to sedimentation of water bodies. This FSP designed also for decreasing number of point that needed for flow transfer from road located in downstream of FSP area. This project increased the number of point to half and so increased costs of road construction. Finally, flood storage and management can be one of the sustainable solutions for ground-water recharge if supported by responsive policies and institutions that will adopt integrated water resources management principles and embrace direct and indirect actors and stakeholders. Reference

Aeschbacher J, Liniger HP, Weingartner R (2005) River water shortage in a highland–lowland system: a case study of the impacts of water abstraction in the Mount Kenya region. Mt Res Dev 25(2):155–162

Al-Qudah KH, Abu-Jabe N (2009) A GIS Database for Sustainable Management of Shallow Water Resources in the Tulul al Ashaqif Region, NE Jordan, Water Resources Management 23(3) 603:615.Boulton, A.J., 2000. River ecosystem health down under: assessing ecological condition in riverine groundwater zones in Australia. Ecosystem Health 6 (2), 108–118

Dhruva Narayana V.V, Sastry G, Patnaik US., 1990.Watershed management. New dwlhi.176pp

Hedelin B (2007) Criteria for the assessment of sustainable water management. Environ Manage 39(2): 151–163

in streams and rivers. Annual Review of Ecology and Systematics 29, 59–81.

Kithinji GRM, Liniger HP (1991) Strategy for water conservation in Laikipia district. Proceedings of a water conservation seminar, Nanyuki, 7–11 August. Laikipia-Mt. Kenya papers, D-4. LRP and Universities of Nairobi (Kenya) and Berne (Switzerland)

Kondolf, G.M., Maloney, L.M., Williams, J.G., 1987. Effects of bank storage and well pumping on base flow, Carmel River, Monterey County, California. Journal of Hydrology 91, 351e369.

Peterjohn, W.T., Correll, D.L., 1984. Nutrient dynamics in agricultural watershed: observations on the role of a riparian forest. Ecology 65, 1466e1475.

Rassam, D., 2005. Impacts of hillslopeefloodplain characteristics on groundwater dynamics: implications for riparian denitrification. In: The International Congress on Modelling and Simulation, December 12e15, Melbourne, Australia, pp. 2735e2741

Rejani R, Madan KJ , Panda SN , Mull R(2008) Simulation Modeling for Efficient Groundwater Management in Balasore Coastal Basin, India, Water Resources Management 22(1) 23:50Todd, G.K., 1995. Groundwater flow in relation to the flooding stream. Proceedings of the American Society of Civil Engineers 81 (628), pp. 20e28

493


Xia J, Zhang L, Liu C, Yu J (2007) Towards better water security in North China. Water Resour Manag 21 (1):233–247.

Table 1: Ground-water level change in tree month interval after flood event

Well sample No.

Distance from FSP

Distance from river

Ground-water level change after flood event (cm) One month Two month Three

month 1 250 120 0.196 0.452 0.386 2 262 510 0.165 0.354 0.345 3 271 420 0.154 0.279 0.258 4 310 270 0.165 0.325 0.278 5 460 152 0.145 0.241 0.123 6 480 570 0.12 0.16 -0.11 7 1100 105 0.06 0.19 -0.41 8 1600 180 0.06 -0.19 -0.31 9 1670 410 0.05 -0.16 -0.46 10 2050 345 0.03 -0.11 -0.48

Figure 1. Schematic of study area and sampled wells

0

20

40

60

80

SEP OCT NOV DEC JAN FEB MAR APR MAY JUNE JULY AUG

Rai

nfal

l (m

m)

0

20

40

60

80

Gro

und-

wat

er le

vel(m

), A

ir Te

mp(

C)

Rainfall Tempreture Groundwater level

Figure 2: Average monthly rainfall, temperature and ground-water level in study area

494


a0

10

20

30

40

50

60

70

2004-2005 2005-2006 2006-2007 2007-2008 2008-2009

Gro

und-

wat

er le

vel(m

)

b

0

50

100

150

200

250

300

350

400

2004-2005 2005-2006 2006-2007 2007-2008 2008-2009

Ann

ual r

ainf

all (

mm

)

Figure 3. Mean of yearly ground-water level (a) and mean of yearly rainfall (b) during study period

Gro

und-

wat

er le

vel

chan

ge(m

)

Gro

und-

wat

er le

vel

chan

ge in

2th

m

onth

(m)

Gro

und-

wat

er le

vel

chan

ge in

2th

m

onth

(m)

a

-1

-0.5

0

0.5

One month Two month Three month

W1 W3 W5 W7 W10

b y = -0.249Ln(x) + 1.7518R2 = 0.8623

-0.4-0.2

00.20.40.6

0 300 600 900 1200 1500 1800 2100

Distance from FSP area(m)

c y = -0.0569Ln(x) + 0.4711R2 = 0.0236

-0.4-0.2

00.20.40.6

50 100 150 200 250 300 350 400 450 500 550 600Distance from river(m)

Figure 4. Mean of ground-water level change after flood event (a), in relationship to distance from FSP area (b) and in relationship to distance from main river(c).

495


Geotechnical Investigation of Sinkhole Occurrence in Kabudrahang Plain, Hamedan Province, Iran

Reza Pirmoradi *, Mohammad Ahmad 1i, Behrouz Yaghoubi2

Corresponding author: M.S.c Student of Hydrogeology, Islamic Azad University , Science and Research Campus, Tehran, Iran

E-mail address: [email protected] .

Abstract Water resource management faces with a lot of problems in arid and semi-arid area because of water crisis and lots of problems in finding water and extracting it, traditional irrigation, climate change and recently droughts. Moreover, irrational extraction of underground water resource causes any irrecoverable damages to environment and these resources. Sinkholes could be classified as irreparable and irrecoverable disaster. For example, in order to unallowable water extraction from underground resources in Famenin and Kabudrahang plains in Hamedan province, underground water level decreases about 2.5 to 3 meters annually. Mean thickness of alluvial deposits in mentioned plains are 70 to 100 meters. Mentioned decrease in underground water level and also reservoir shortage causes sinkholes and land subsidence in those plains that the number of sinkholes is 35 and the magnitude of land subsidence is about 35 centimeters in recently two decades. In the aim of managements and making applied decisions to eliminate the occurrence of this phenomenon, correct knowledge of its occurrence mechanism and creating a local data base of sinkholes could be beneficial. In this research, geotechnical mechanism of sinkhole occurrences, in Kabudrahang plain has been encountered and finally any conclusions have been presented. Keywords: Sinkhole; Geotechnical Investigation; Underground water table; 1-Introduction According to UNICCO definition, subsidence is downfall or land settlement, which has occurred in different dimensions and different reasons. Usually this phenomenon could be described by perpendicular motion of land surface that has small horizontal vector. This definition doesn’t contain any settlement or slip slop observations, such as landslide, because these movements are almost horizontally and also in disturbed soils, occurrence mechanism could change and be in a different manner. In general, land subsidence and sinkholes should be considered in two different categories. The first one, which belongs to general settlement of plains, could be called “land subsidence”. Mentioned phenomenon has been accessed in some plains such as Kerman, Rafsanjan, Abarghoo, Yazd and Ardakan plain. Second section is related to subsidence in limited and depth zones that are sinkholes or Dolin and occurred in the regions under study. Dimensions and depth of sinkholes are different, and from the most important types of those are Kabudrahang, Famenin, Hamekasi sinkholes and other small types are Maharloo plain sinkholes in Fars province.[1] Several factors are effective to create this phenomenon out of which solution, ice-melting, sedimentary concentration, plan slow motion and magma eruption, or human operations such

1 M.s.c in civil engineering, Hamedan bu ali university 2 Water budget research and study bureau manager of Hamedan province

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as mining or groundwater and oil consumption can be referred. Pay attending to geological situation and already done geophysical studies in the area under investigation indicating the existence of alluvium on top of carbonate bedrock and with respect to it, it can certainly be a referent as the origin of karstic. An example of sinkholes seen in the area of kabudrahang plain has been presented in figure (1)

Figure left: An example of sinkholes seen in the area of kabudrahang plain, [right]: the largest sinkhole in our country

Figure (2) is related to the largest sinkhole in our country near to villages Baban and Ghozlije 5 kilometers to kabudrahang city. These sinkholes have occurred and we tried to portray them. Today in most of Iran plains, sinkholes can be seen. The plains of Tehran, Isfahan, Hamedan, Kerman, are with the largest number of sinkholes. 2-Methodology Through the comprehensive investigation which was done during the study, and based on the information gathered at the field study stage, the exact location of sinkhole was determined and also, a map of the sinkholes was drawn having compared with the map of faults of area, It was seen that the process the sinkholes are in accordance with the young faults. In addition, by investigating the available reports of geophysical and geotechnical studies and comparing them with the nearby wells log, and geological reports of the area, the exact mechanism of sinkholes was determined. And then, having introduced the scope of study, and the sinkhole situation, first an introduction of karstic sinkholes and the study of their formation in this the area, and also the understanding of geotechnical structure around the sinkhole, some related factors will be represented. Finally the results of the present study will be discussed. 3-The Geographic situation of the study As it has been shown in map 1, the area of the study included in Hamedan province which its situation is between 48° 30’ 00” and 49° 30’ 00” eastern hemispheroid, and 34° 45’ 00” and 35° 30’ 00” northern hemispheroid. The study area and Razan-Ghahavand area in Hamedan province possesses the largest number of sinkholes in the province.

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Map 1 : The area of the study and situation of sinkholes

4- An introduction to karstic sinkhole and the study area of their formation process in the area of study. 4-1- Karstic sinkholes Karstic sinkholes can be categorized into three main classes (solution, subsidence, and collapse). The collapsible sinkholes especially the cap ones are the most problematic and causing financial damages and casualty. These sinkholes are formed only in an area having adhesive soil on the top of karstic carbonate. It is important to mention that in this formation there must be several channels in the depth of karstic formations which can transfer water. This condition leads to increase the speed of water vertically and horizontal as a result, the transferred sediment of the cavities is created on the border between soil and carbonate. And by the cavity getting larger, the cavity ceiling strength decreases, and consequently it collapses suddenly. Human being by these activities specially by dropping the level of aquifer or by concentrating runoff causes the collapsible cap sinkhole to happen faster. By geological and karstic hydrogeologic studies, one can identify areas with the possibility of sinkholes by paying attention to the vast area of the karstic formation in the Zagros mountain range; the number of dangerous sinkholes is low in Iran due to the geological features of the Zagros.[3] 4-2- The study of the formation process of sinkholes in the area In the manifestation of karsts in the studied area has provided the right condition to create the main reason for creating sinkholes in the sediment of alluvium of upper surface during hundreds or thousands of years. The collapse of the ceiling the karsts activities cavities in the mass of carbonate bedrock which is mainly created by the solution erosion during the process, makes the parts separate and creates many cavities that these points of creating sinkhole and finally the movement and transfer of the alluvium covering materials to the deeper areas and their washing-away by the lateral currants happen. Generally, the development of cavities in the alluvium and the soil transfer into those cavities in the bedrock happens in two ways of vertical and lateral. The effective factors in vertical transfer are: the adhesiveness persistence, wetness, the size of forming materials, and finally the size of cavities and cracks in the bedrock. The effective factors in lateral are as follows: the speed of water in the horizontal channels of the bedrock and the size of the collapsible materials of the model of process of buried sinkhole formation. These factors show the mechanism of sinkhole formation in two ways: the homogeneous and non-homogeneous alluvium mass.[2]

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5-The understanding of geotechnical formation of earth around the sinkhole By drilling an exploration well About 4 inches to 115 meters through rotary technique with the random sampling without using drilling mud in 15 meters distance to the edge of Jahan abad sinkhole in formation plain, the geotechnical conditions of the area was investigated. The kind of subsurface soil up to 93 meters down includes the diversity of fine grains which have passive such as silty clay (CL) and clay silt (ML) and also silty clay sand layers (SC/SM), they are according to unified ranking. The silty clays usually have average plasticity and also their common liquid limit is between %31.2 and %47.2.The bed rock at 93 meters down includes calcareous Breccias with tiny cavities which are 109 to 119 meters with relatively large cavities. The level of groundwater at 109.5 meter down indicates the mass of alluvium of unsaturated covering with blow-up of sand materials (collapse of piling of materials from deep horizon of cavities in the bedrock).[4] 6-Conclusions Based on investigations, measurements and field studies, it can be shown that: 6-1- solution cavities, water channels, faults and cracks system in milestone bedrock and irregular water pumping that has in those is the major factor for sinkhole occurrence in the area. It is important to mention that any factors such as sand washing-away, wells gas out and very speed decrease groundwater table affect in speed up sinkhole occurrence 6-2-it can be mentioned that the major factor of carbonate solution is carbon dioxide with hydrothermal, penomality and atmospheric origin that solution in groundwater, that dioxide with atmospheric region approaches mero-karst and carbon dioxide with internal region approaches holo-karst 6-3- Paying attention to done studies about Hamedan sinkholes it was ignored the importance and majority factor and has been the claim that there aren’t effective faults in sinkhole occurrence and just very high harvesting of ground water and sinkholes dispersal aren’t in accordance with special trend. But paying attention to studies, the sinkholes situation is systematic and the major factor is three groups that occur in tertiary. These faults has been oligomiusen carbonate karstification that it is the preliminary and importance factor of sinkhole occur or generally can have been this claim that sinkholes dispersal in accordance with faults trend. The achievement of the integration map of subsidence sinkhole scattered plains Hamedan obtained tectonic Sitemap So that the dispersion around sinkhole in existing faults are plain. 6-4-One important factor in expediting the creation of natural phenomena and the Earth Summit created sinkhole groundwater table change and eventually disassemble stable balance between vertical stress and inhibitory forces in the crust of soil mass is, The famenin and Kabudrahang plains also provided the model surface of a reduction in groundwater level during the past two decades with the increased utilization is and Effect of soil covering the rock bed column in expediting the process of creating this phenomenon can be identified as follows: 6.4.1- Loss Buoyant Support in the ceiling cavities in the bedrock mass that already have water storage and eventually created tension changes in soil mass 6.4.2- Vertical speed flow of underground water level depth in alluvial mass due to increased hydraulic gradient along the vertical pressure change due to piesometeric

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6.4.3- Increasing range of water level eventually changes the water level of underground bedrock surface and drainage through to complete the mass to the upper alluvial 6.4.4- Phenomenon created to make feeding easier to create vertical and establishing vertical flow surface to a depth of penetration to achieve seamless system and gaps and cavities in the rock mass bed References

[1] M, A, Sanaie, Study of water resources exploitation and subsidence phenomenon causes and adverse effects and creating sinkholes meeting in Hamadan plains The conference on hazard of sinkholes in karst terrains28 dec 2005

[2] GH, Saadati, Understanding the phenomenon of land subsidence and land subsidence Kabudrahang famenin plains in Hamedan, Contact sinkholes central plain of Hamadan tectonic zone status, the conference on hazard of sinkholes in karst terrains28 dec 2005

[3]E, Reissi Ardakani, Incident maker Karstic sinkhole and the potential of creating, the conference on hazard of sinkholes in karst terrains28 dec 2005

[4]F, Parvizi, The understanding sinkholes and land subsidence around Famenin-Kabudrahang plains, the conference on hazard of sinkholes in karst terrains28 dec 2005

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Estimating the Abrasion Resistance of Rock Aggregates from the P-wave Velocity

Sair Kahraman*, Mustafa Fener, Osman Gunaydin

*Corresponding author: Mining Engineering Department, Nigde University, Nigde, Turkey Phone number: +90-388-2252264, E-mail address: [email protected]

Abstract The prediction of Los Angeles (LA) abrasion loss from some indirect tests is useful especially for the preliminary. For this purpose, LA abrasion, P-wave velocity, density and porosity tests were carried out on 35 different rock types such as igneous, metamorphic and sedimentary rocks. The test results were analysed using the method of least squares regression. The LA values were correlated with the P-wave velocity values and no correlation was found between the two parameters for all rocks. The regression analysis was repeated for the rock classes respectively. An acceptable correlation was found only for sedimentary rocks.To check the possibility of obtaining the more significant relations, multiple regression analysis was applied to the data including porosity and density. However, the correlation coefficients of the multiple regression models were not strong. Multiple regression analysis was repeated for the rock classes respectively. Multiple regression models having good correlation coefficients were obtained for the rock classes. Concluding remark is that LA abrasion loss of aggregates can be estimated from the multiple regression models derived for the rock classes. 1. Introduction The demand of crushed stone aggregates has increased from day to day in the world as a result of increasing expansion of highway and other construction works and decreasing natural aggregate resources. Different types of rocks such as igneous, metamorphic and sedimentary are used as aggregates in a wide variety of applications including portland cement concrete and asphalt production, road/rail base, drainage systems etc. The rocks to be used as an aggregate must have some physical and mechanical properties. Abrasion resistance is one of the important properties of crushed rock aggregates. Los Angeles (LA) abrasion test is a standard method to measure the abrasion resistance of aggregates. Although the method is relatively simple it is time consuming and expensive comparing to the indirect tests, such as ultrasonic test. In addition, at least 5000g sample is necessary for the LA abrasion test. Ultrasonic techniques are widely used in various fields such as mining, geotechnical, civil, and underground engineering, since they are non-destructive and easy to apply. These techniques are usually employed both in site and laboratory to characterize and determine the dynamic properties of rocks. If a strong correlation between LA abrasion loss and ultrasonic velocity are found, ultrasonic test can be used for the prediction of the abrasion resistance of aggregates especially for the preliminary investigations. Several researchers [1-10] have investigated the relations between the the LA abrasion loss and some rock properties. However, any study on the relation between the LA abrasion loss and P-wave velocity could not be found. In this study, the possibility of estimating the abrasion resistance of aggregates from the P-wave velocity was investigated using the regression analysis.

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2. Sampling A total of 35 rock types were sampled, 9 of which were igneous, 11 of which were metamorphic and 15 of which were sedimentary. Quarries, granite and marble factories, and natural outcrops in Nigde, Kayseri, Konya and Antalya areas of Turkey were visited and rock blocks were collected. An attempt was made to collect rock samples that were large enough to obtain all of the test specimens of a given rock type from the same piece. Each block sample was inspected for macroscopic defects so that it would provide test specimens free from fractures, partings or alteration zones. The location and the name of the rocks are given in Table 1. 3. Experimental Studies 3.1. Los Angeles Abrasion Test ASTM method C 131-66 was used for the LA abrasion test. Test samples were oven-dried at 105-110OC for 24 hr and then cooled to room temperature before they were tested. There are four aggregate size grading to choose from in the ASTM method. Grading D was used in the tests. 6 steel spheres were placed in a steel drum along with approximately 5000g aggregate sample and the drum was rotated for 500 revolutions at a rate of 30-33 rev/min. After the revolution was complete, the sample was sieved through the No. 12 sieve (1.7 mm). The amount of material passing the sieve, expressed as a percentage of the original weight, is the LA abrasion loss or percentage loss. 3.2. Ultrasonic Test NX (54 mm) samples were cored from the block samples in the laboratory. End surfaces of the core samples were cut and polished sufficiently smooth plane to provide good coupling. A good acoustic coupling between the transducer face and the rock surface is necessary for the accuracy of transit time measurement. Ultrasonic gel was used as a coupling agent in this study. Transducers were pressed to either end of the sample and the pulse transit time was recorded. P-wave velocity values were calculated by dividing the length of core to the pulse transit time. In the measurements, the PUNDIT and two transducers (a transmitter and a receiver) having a frequency of 1 MHz were used. 3.3. Density Test Trimmed core samples were used in the determination of dry density. The specimen volume was calculated from an average of several calliper readings. The dry weight of the specimen was determined by a balance, capable of weighing to an accuracy of 0.01 of the sample weight. The density values were obtained from the ratio of the specimen weight to the specimen volume. 3.3. Porosity test Porosity values were determined using saturation and calliper techniques. Pore volumes were calculated from dry and saturated weights and sample volumes were obtained from calliper readings. The porosity values were obtained from the ratio of the pore volumes to the specimen volume. The summarized results of LA abrasion, ultrasonic, density and porosity tests for each rock type are given in Table 1.

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Table 1. The location and the name of the rocks tested and test results.

Location

Rock type

Rock class

LA abrasion loss (%)

P-wave velocity (km/s)

Porosity (%)

Density (g/cm3)

Altinhisar/Nigde Basalt Igneous 17.2 4.5 5.50 2.58 Tepekoy/Nigde Andesite Igneous 18.2 3.8 7.19 2.53 Azatli/Nigde Andesite Igneous 18.3 4.9 1.15 2.57 Uckapili/Nigde Granodiorite Igneous 29.7 3.0 2.51 2.54 Uckapili/Nigde Metagabro Igneous 10.2 6.0 0.65 2.94 Uckapili/Nigde Granite Igneous 15.7 4.5 1.15 2.63 Ortakoy/Aksaray Granite (Anadolu grey) Igneous 33.7 5.0 0.62 2.55 Kaman/Kirsehir Granite(Kaman Rosa) Igneous 40.3 4.6 0.63 2.61 Kaman/Kirsehir Granite (Kırcicegi) Igneous 34.7 4.0 0.98 2.47 Gumusler/Nigde Quartzite Metamorphic 20.2 5.7 0.85 2.72 Gumusler/Nigde Marble Metamorphic 45.5 5.3 0.37 2.69 Uckapili/Nigde Marble Metamorphic 40.6 5.7 0.37 2.68 Altindag/Kutahya Marble Metamorphic 28.8 4.7 0.06 2.55 Iscehisar/Afyon Marble Metamorphic 47.2 5.1 0.13 2.55 Yatagan/Muğla Marble Metamorphic 73.2 4.0 0.30 2.57 Gumusler /Nigde Amfibolsişt Metamorphic 22.3 5.6 1.90 2.75 Gumusler /Nigde Gneiss Metamorphic 40.5 3.0 0.79 2.70 Gumusler /Nigde Micaschist Metamorphic 37.7 2.6 1.95 2.49 Gumusler /Nigde Migmatite Metamorphic 16.6 6.2 1.33 2.75 Kilavuzkoy/Nigde Serpentinite Metamorphic 15.9 5.4 0.91 2.73 Sogutalan/Bursa Limestone Sedimentary 33.3 6.1 0.69 2.56 Korkuteli/Antalya Limestone Sedimentary 28.9 6.2 0.38 2.57 Basmakcı/Nigde Limestone Sedimentary 23.3 5.5 0.18 2.69 Yahyali/Kayseri Dolomitic limestone Sedimentary 25.0 6.1 0.31 2.58 Fethiye/Mugla Limestone Sedimentary 35.6 6.1 0.18 2.57 Bunyan/Kayseri Limestone Sedimentary 24.7 6.0 0.93 2.57 Gokbez/Nigde Travertine Sedimentary 21.9 5.2 7.22 2.51 Yıldızeli/Sivas Travertine Sedimentary 31.4 5.4 3.12 2.40 Finike/Antalya Travertine (Limra) Sedimentary 42.3 4.3 5.93 2.31 Bucak/Burdur Travertine (Limra) Sedimentary 75.9 3.7 12.57 2.13 Demre/Antalya Travertine (Demre stone) Sedimentary 54.5 5.5 2.15 2.39 Demre/Antalya Travertine (Limra) Sedimentary 45.3 4.0 13.27 2.09 Godene/Konya Travertine Sedimentary 40.1 5.4 4.08 2.33 Mut/Icel Travertine Sedimentary 61.9 4.0 8.74 1.93 Karaman Travertine Sedimentary 39.0 5.4 4.04 2.29

4. Evaluation of the results The test results were analysed using the method of least squares regression. Linear, logarithmic, exponential and power curve fitting approximations were tried and the best approximation equation with highest correlation coefficient was determined. The L A. values were correlated with the P-wave velocity values and no correlation was found between the two parameters for all rocks (Figure 1). To see the correlation degrees for the rock classes, regression analysis were performed for igneous rocks, metamorphic rocks and sedimentary rocks, respectively (Figures 2-4). An acceptable correlation was found only for sedimentary rocks.

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Figure 1. The relation between P-wave velocity and LA abrasion loss.

y = 73.2e-0.27x

r = 0.48

05

1015202530354045

0 1 2 3 4 5 6 7

LA a

bras

ion

loss

(%)


Figure 2. The relation between P-wave velocity and LA abrasion loss for igneous rocks.

y = -6.9x + 68.5r = 0.47

01020304050607080

0 1 2 3 4 5 6 7

LA a

bras

ion

loss

(%)


Figure 3. The relation between P-wave velocity and LA abrasion loss for metamorphic rocks.

0

10

20

30

40

50

60

70

80

0 1 2 3 4 5 6 7

LA a

bras

ion

loss

(%)


504


y = -67.1Ln(x) + 149.3r = 0.76

0

10

20

30

40

50

60

70

80

0 1 2 3 4 5 6 7

LA a

bras

ion

loss

(%)


Figure 3. The relation between P-wave velocity and LA abrasion loss for sedimentary rocks. To check the possibility of obtaining the more significant relations, multiple regression analysis was applied to the data including porosity and density. However, the correlation coefficients of the multiple regression models were not strong. The derived models are given below:

pV3.32.64n6.18.216LA −γ−−= r = 0.68 (1)

pV4.4n1.17.52LA −−= r = 0.43 (2)

pV5.24.449.158LA −γ−= r = 0.65 (3)

where, LA is the LA abrasion loss (%), n is the porosity (%), γ is the density (g/cm3) and Vp is the P-wave velocity (km/s). Multiple regression analysis was repeated for the rock classes respectively. Multiple regression models having good correlation coefficients were obtained for the rock classes. These models are given following: For igneous rocks, pV5.26.44n5.22.157LA −γ−−= r = 0.77 (4)

For metamorphic rocks, pV2.65.32n4.128.161LA −γ−−= r = 0.73 (5)

For sedimentary rocks, pV6.70.52n2.15.208LA −γ−−= r = 0.82 (6)

As shown above the correlation coefficients of multiple regression models for the rock classes are higher than that of multiple regression models for all rocks. 5. Conclusions To investigate the predictability of LA) abrasion loss from the P-wave velocity, 35 different rock types such as igneous, metamorphic and sedimentary rocks were tested. The test results were first analysed using the simple regression analysis. Then, including porosity and density multiple regression analysis was performed for all rocks and the rock classes respectively. Multiple regression models for the rock classes have good correlation coefficients. It was concluded that LA abrasion loss of aggregates can be estimated from the derived multiple regression models for the rock classes especially for the preliminary studies.

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References

1- Kazi, A. and Al-Mansour, L.R., 1980, Empirical relationship between Los Angeles Abrasion and Schmidt hammer strength tests with application to aggregate around Jeddah: Quarterly Journal of Engineering Geology., v. 13, p. 45-52.

2- Ballivy, G. and Dayre. M., 1984, The mechanical behaviour of aggregates related to physicomechanical properties of rocks: International Association of Engineering Geology Bulletin, v. 29, p. 339-342.

3- Cargill, J.S. and Shakoor, A., 1990, Evaluation of empirical methods for measuring the uniaxial compressive strength of rock: International Journal of Rock Mechanics and Mining Science, v. 27, p. 495-503.

4- Shakoor, A. and Brown, C.L., 1996, Development of a quantitative relationship between unconfined compressive strength and Los Angeles abrasion loss for carbonate rocks: International Association of Engineering Geology Bulletin, v. 53, p. 98-103.

5- Kasim, M. and Shakoor, A., 1996, An investigation of the relationship between uniaxial compressive strength and degradation for selected rock types: Engineering Geology., v. 44, p. 213-227.

6- Al-Harthi, A.A., 2001, A field index to determine the strength characteristics of crushed aggregate: Bulletin of Engineering Geology and The Environment, v. 60, p. 193-200.

7- Kahraman, S. and Fener, M., 2007, Predicting the Los Angeles abrasion loss of rock aggregates from the uniaxial compressive strength: Materials. Letters, v. 61, p. 4861-4865.

8- Kahraman, S. and Gunaydin, O., 2007, Empirical methods to predict the abrasion resistance of rock aggregates: Bulletin of Engineering Geology and The Environment, v. 66, p. 449-455.

9- Kahraman, S. and Toraman, O. Y., 2008, Predicting the Los Angeles abrasion loss of rock aggregates from crushability index: Bulletin of Materials Science, v. 31, p. 173-177.

10- Kahraman, S. and Fener, M., 2008. Electrical resistivity measurements to predict the abrasion resistance of rock aggregates: Bulletin of Materials Science, v. 31, p. 179-184.

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Determination of crustal velocity model in Fars province using simultaneous inversion of local earthquake travel times

Sayyed Mahmood Azhari*,Mostafa Javanmehri,Mehdi Rezapour

Corresponding author: Institute of Geophysics of University of Tehran, 1435944411Tehran, Iran

[email protected](S.M.Azhari)*,[email protected](M.Javanmehri),[email protected](M.Rezapour) Abstract Geomorphological observations reveal a major oblique fold in Fars province. A sum of thrust and right-lateral fault was located in this region, where some earthquakes occurred in there. These earthquakes killed inhabitants and left widespread devastation in recent century. Therefore, fault structures in southwestern Fars province do appear to be active in the late Quaternary and may be capable of producing destructive earthquakes in the future. Seismicity analysis of this area requires the precise locations of occurred earthquakes. The Iranian seismic networks have been operated since 1996. The existing earthquake catalogue routinely generated by the IRanian Seismological Center (IRSC), due to un-modeled velocity structure, are in large errors. The availability of a large number of phase data collected by IRSC, for 11 years, has motivated this study to develop a reliable crustal velocity model, accurate locations of earthquakes and obtain an enhanced picture of seismicity of region. No previous studies have been carried out in this region for crustal structure. We determine an optimum 1D velocity model by using the VELEST algorithm for reliable determination of earthquake hypocenter locations. Applying the obtained velocity model for relocation of about 2956 recorded events show a significant improvements over locations, which are routinely determined by the IRSC. There are new coherent alignments both in depths and epicenters in this region which have not been seen until now. Keywords: Seismicity, Seismotectonic Province, Fars, crustal structure, Vp /Vs 1-Introduction The NW-SE trending Zagros fold and thrust belt, one of the ranges of the Alpine – Himalayan belt, extends for about 1800 km from a location some 300 km southeast of the East Anatolian Fault in northeastern Turkey to the Strait of Hormuz where the north-south trending Zendan-Minab-Palami fault system separates the Zagros belt from the Makran accretionary prism. This range are formed by closure of the Neo-Tethys ocean and then continental collision, starting in the Miocene (McQuarrie et al., 2003), between the Arabian plate and Central Iran. The Zagros range currently accommodates almost half of NS shortening between the Arabia and Eurasia (Vernant et al., 2004). This active fold and thrust belt is subdivided into five morphotectonic units: the High Zagros Thrust Belt, the simple Fold Belt, the Zagros Fordeep, the Zagros Coastal Plain and the Persian Gulf-Mesopotamian lowland (Berberian, 1995). Studied region in this paper located in Fars province, in the High Zagros Thrust Belt, north eastern part of this region is Abarkuh desert that located in central Iran is less active than the other border region around studied region. The west and southeastern part of this region is located in Zagros seismotectonic province that a lot of earthquakes were seen (Figure1). In this paper we study crustal structure of the Fars province based on recorded earthquakes by a Shiraz seismic network from June 2002 to

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November 2009 and seismicity from International Seismological Centre (ISC) catalog, Harvard Centroid Moment Tensor (CMT) catalog and historical earthquakes catalog (Ambraseys & Melville, 1982) in the northern part of Fars province. Crustal structure of this region is particular issue that is not yet resolved in the studied region. 2-Data analysis In order to study of the crustal structure of studied region, we use from Shiraz network that have 5 stations (Figure 2). To improve the velocity model, we selected a subset of 125 events, recorded by a minimum of 3 stations, with an azimuthal gap less than 270º, residual RMS less than 0.5 s and uncertainties both in epicenter and depth less than 5 km. With these criteria the trade-off between the velocity structure and the location of the events is small. Plotting Tsj-Tsi (S arrival time to stations i and j respectively for same event) versus Tpj-Tpi (P arrival time to stations i and j respectively for same event) for all events and all stations, we compute a Vp /Vs ratio of 1.77 ± 0.03 with 908 arrival times (Figure 3) (Gholamzadeh et al., 2009). We inverted the arrival times of the selected set of events for a 1-D velocity structure using the program VELEST (Kissling, 1988). The result of these inversions(Figure 4) suggests that no more than four layers are resolvable(table 1).After using calculated 1D model the corresponding residual RMS reduces from 0.3 s to 0.15 s for the final four-layer model. We assume 4 models with p velocity, s velocity, average of p velocity and average of s velocity (Figure 4). 3-Conclusions In this study we investigate seismicity and seismotectonic of fars province and we understand that this region has a high potential region that a lot of earthquakes were seen. Most of faults in this region have a NW-SE trend and earthquakes mechanism is reverse. Vp /Vs ratio was assessed 1.77 ± 0.03 that clearly adapt with other identical studies were perform in this region. The result of inversion was display a four layer model and because most of our earthquakes are in low depth we can't approximate moho depth in this region. References

[1] Ambraseys, N. N., Melville, C. P., 1982, A history of Persian earthquakes: Cambridge University Press, Cambridge, UK.

[2]Berberian, M., 1995. Master "blind" thrust faults hidden under the Zagros folds: active basement tectonics and surface morphotectonics. Tectonophysics 241, 193-224.

[3] Centroid Moment Tensor catalog: Harvard University, Department of Geological Sciences, available online at: http://www.globalcmt.org/CMTsearch.html

[4]Gholamzadeh, A., 2009. Seismicity, seismotectonics and velocity structure of the south easternmost Zagros. Ph.D. Thesis, International Institute of Earthquake Engineering and Seismology.

[5] International Seismological Center catalog: UK, available online at: http://www.isc.ac.uk

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[6]Kissling, E., 1988. Geotomography with local earthquake data. Reviews of Geophysics 26, 659-698.

[7]McQuarrie, N, Stock, J. M., C. Verdel, Wernicke, B. P., 2003. Cenozoic evolution of Neotethys and implications for the causes of plate motions. Geophys. Res. Let. 30, 2036, doi:10.1029/2003GL017992, 2003.

[8]Vernant, P., Nilforoushan, F., Hatzfeld, D., Abbasi, M.R., Vigny, C., Masson, F., Nankali, H., Martinod, J., Ashtiany, A., Bayer, R., Tavakoli, F., Chéry, J., 2004. Present day crustal deformation and plate kinematics in the middle east constrained by GPS measurements in Iran and Northern Oman. Geophysical Journal International 157, 381-398.

Table 1: Final velocity structure calculated by 1-D inversion method for studied region.

Top of the layer (km) P velocity (Km s-1 )

0 6 10 14

5.70 ± 0.03 5.82 ± 0.05 6.52 ± 0.03 6.65 ± 0.03

Figure 1: Seismicity and focal mechanisms of the Fars province. Focal spheres in red are CMT solutions computed by waveform modeling that assume from from International Seismological Centre (ISC) catalog, Harvard Centroid Moment Tensor (CMT) catalog and historical earthquakes catalog (Ambraseys & Melville, 1982)

509


Figure 2: Configuration of Shiraz network from Figure 3: Vp/Vs ratio computed for the June 2002 to November 2009 in the south studied region from 908 arrival times Northern part of Fars province.

(A)

(B)

(C)

Figure 4: Good convergence of the final calculated velocity model by 1-D inversion of travel times. P velocity model (A), s velocity model (B) Left figures shows initial random models and right ones are final models. Average of p and s velocity(c).

510


Fourier Analysis Models and Their Application to River Flow’s Prediction

Soheil Ghareaghaji Zare1 - Mohammad Hossein Karimi Pashaki2 – Hosein Sedghi3

1(M.SC) student in Water Science and Engineering, IAU-science and research branch of Tehran-IRAN [email protected]

2(M.SC) student in Water Science and Engineering, IAU-science and research branch of Tehran-IRAN [email protected]

3Prof. Faculty of Water Science and Engineering, IAU -science and research branch of Tehran -IRAN [email protected]

Abstract The forecasting of hydrologic systems by using the date of the system is one of the most important advantages of time series analysis (dynamic systems) in water science. By using time series analysis that is based on mathematical logics and statistical solutions and recent electronic solution methods, it is possible to evaluate the system's reactions in advance by using the systems past behavior characteristics. In most water resource systems design and operation studies, the periodic phenomena have been represented by Fourier functions. After Quimpo (1967), Fourier analysis has become a standard tool in any hydrologic study concerning periodicity because Fourier analysis and modeling present powerful tools to analyze different periodic events behavior. For analysis and design of water resource systems, it is sometimes useful to generate high- resolution synthetic river flows. Modeling and simulation of river flow time series is an important step in the planning and operational analysis of water resources systems. Thus, this paper compares three different Fourier based models in their capabilities and results. These three models are: Fourier PARMA models, Adapted Fourier analysis with kalman filter(AFAM), Fourier series ARIMA model(FSAM). These models test on “shahar-chayi” river flow. It is prospected that the results show the best way and its reliability. Keywords: Fourier analysis, Fourier transforms, river flow, kalman filtering. Introduction Numerous factors contributed in environmental changes which ultimately resulted in creation of variable environs morphologically as well as applicably. Among the most vital factors is erosion which plays a crucial role in appearance and land use changes. Significant sorts of erosion include wind erosion, hydro-erosion as well as erosion due to human applications. Water with a surprising power is a key component in erosion and sedimentation riverbeds and coastal lines. Moreover, valleys and vast plains are formed due to water erosion which is mainly associated with water flow. To measure the water flow a quantity called “discharge” is applied. Thus, study of river erosion is carried out based on information about water flow (discharge measurement) in combination with geological properties. In this regard, investigation of collected data which provide the time series of river discharge is considered as a rational and applicable method to predict the future flow values. A natural river flow process has significant periodic behavior in mean, standard deviation, skewness, and serial dependence structure. This study aims to investigate and compare three conventional methods applied to measure flow discharge based on analysis of time series which include: 1.Fourier

511


Series ARIMA models (FSAM) 2.Adapted fourier analysis with “kalman” filter(AFAM) 3.Fourier PARMA models. These models test and compare on natural river flow. Fourier series ARIMA models (FSAM) Mostly, it is easier to show a function by a set of primary functions called as ”base”. So that it could be possible to illustrate the whole studied functions as linear composites of primary functions in base. Among the applicable function are (sin) as well as (cos) functions or mixed indices directly applicable to frequency analysis. In 1976, the studied model was applied for the first time by “Bloomfield” to analysis the time series in hydrology. “Afshar” and “Fahmi” (1996) provided a model to predict the rainfall in Iran by combining Fourier model with ARIMA models. Fourier model is a mathematical structure designed of Fourier equation in combination with “Markov model”. Fit pattern Fit pattern is represented as follow: ξδµ tntttnX ,, += (1)

Where, µ tand δ t

are average coefficient and standard deviation of harmonic series,

respectively which are computed by following equation:

)22(1

tjSintjCos BAm jj

jxt ωπ

ωπω

µ ++= ∑=

(2)

Where, ω is series frequency period. To compute the February series expansion coefficient ( Bj

and Aj), following equation is

used:

tjCosj

jj mA ωπ

ω

ω 221∑=

= (3)

tjSinj

jj mB ωπ

ω

ω 221∑=

= (4)

In the above relation, mt is average of inputs in a distinct interval time (month) during the

statistical period and mx is the total average of inputs.

Standard deviation of harmonic series,δ t , could be measured as:

)22(1

tjSintjCos BAS jj

jtt ωπ

ωπω

δ ′∑ ′ ++==

(5)

Where,

tjCosj

tj SA ωπ

ω

ω 221∑′=

= (6)

tjSinj

tj SB ωπ

ω

ω 221∑′=

= (7)

St= standard deviation of inputs in a distinct interval time (month) during statistical period

512


Adapted Fourier analysis with “kalman” filter (AFAM) AFAM model provided on the basis of a complicated mathematical structure has been simulated using statistic, mathematic as well as electronic sciences to predict the dynamic systems. “Zeki chen” (1980) attentively simulated discharge of flow in “Guta” and “Colombia” rivers and then predicted the future levels for the studied rivers. This model then called as kalman model: (8) )11(ˆ)1,()1(ˆ −−−=− iiYiiiiY φ

(9) )()1,()11()1,()1( iQiiiiPiiiiP +−−−−=− φφ (10) [ ] 1)()()1().()()1()( −

+−−= iRiHiiPiHiHiiPiK TT

(11) [ ])1(ˆ)()()()1(ˆ)(ˆ −−+−= iiYiHiZiKiiYiiY (12) [ ] )1()()()( −−= iiPiHiKIiiP

There are three essential requirements in the model designed on the basis of kalman filter model: 1- state variable vector 2- Rule of transfer the state variable from one time to a further time 3- Primary state vector In this model, Fourier equation is used as mode variable vector. In other words, the considered equation is the simulator function for real values. To design the model according to mentioned above analysis, by computation of )1()( −− ixix , following equation is achieved:

{ }[ ] { }[ ]( ) )()1(cos)cos()1()1(sin)sin()1()1()(1

iikkiiBikkiiAixixm

kkk ωγγγγ +−−−+−−−+−= ∑

=

(13)

))1(cos()cos()),1(sin()sin( −−=−−= ikkiikki kk γγβγγα (14)

[ ] )()1()1()1()(1

iiBiAixixm

kkkkk ωβα +−+−+−= ∑

=

(15)

⎥⎥⎥⎥⎥⎥⎥⎥⎥⎥⎥⎥

⎦

⎤

⎢⎢⎢⎢⎢⎢⎢⎢⎢⎢⎢⎢

⎣

⎡

+

⎥⎥⎥⎥⎥⎥⎥⎥⎥⎥⎥⎥

⎦

⎤

⎢⎢⎢⎢⎢⎢⎢⎢⎢⎢⎢⎢

⎣

⎡

−−

−−−−−−

⎥⎥⎥⎥⎥⎥⎥⎥⎥⎥⎥⎥

⎦

⎤

⎢⎢⎢⎢⎢⎢⎢⎢⎢⎢⎢⎢

⎣

⎡

=

⎥⎥⎥⎥⎥⎥⎥⎥⎥⎥⎥⎥

⎦

⎤

⎢⎢⎢⎢⎢⎢⎢⎢⎢⎢⎢⎢

⎣

⎡

00

00000

)(

)1()1(

)1()1()1()1()1()1(

.

10...00000001000000000010000000010000000010000000010000000010

...01

)()(

)()()()()()(

2

2

1

1

2211

2

2

1

1

MMMMMMMMMM

i

iBiA

iBiAiBiAiMix

iBiA

iBiAiBiAiMix

m

m

mm

m

m

ωβαβαβα

Mathematical illustration of above matrix is: (16) )()1().1,()( iWiYiiiY +−−= φ

513


Fourier-Parma Models In the area of stochastic hydrology, standardizing or filtering is used to transform periodic time series to stationary series before fitting stationary stochastic models but standardizing or filtering of most river flow series will not yield stationary residuals due to periodic autocorrelations. in these cases, the resulting model is mis specified. To model such periodicity in autocorrelations, periodic autoregressive moving average (PARMA) models can be employed. in most cases, PARMA models have been applied to time series at a time scale of a months or more. However, when the number of periods is large (e.g, weekly data), PARMA models estimation of an exorbitant number of parameters, hereto for making PARMA modeling virtually impractical. the parsimony in these models is achieved by expressing the periodic model parameters in terns of their discrete fourier transforms. to find a parsimony model in time river discharge time series, “Tesfaye” e.t al(2007) found from their experience that it is prudent to initially fit a PARMAυ (1,1) model to the data. for more complicated PARMAυ (p,q) models, the periodic ARMA process{ }tX~ with periodυ (denoted

by PARMAυ (p,q))and the fourier series representation of the parameters )(),( ll tt θφ and tσ are

jt

q

jtt

p

jjttt jXjX −

==− ∑∑ −=− εθεφ

11)()( (17)

( ) ( ) ( )∑= ⎭

⎬⎫

⎩⎨⎧

⎟⎠⎞

⎜⎝⎛+⎟

⎠⎞

⎜⎝⎛+=

k

rararat

rtSINlSrtCOSlClC1

022υπ

υπθ (18)

( ) ( ) ( )∑= ⎭

⎬⎫

⎩⎨⎧

⎟⎠⎞

⎜⎝⎛+⎟

⎠⎞

⎜⎝⎛+=

k

rbrbrbt

rtSINlSrtCOSlClC1

022υπ

υπϕ (19)

∑= ⎭

⎬⎫

⎩⎨⎧

⎟⎠⎞

⎜⎝⎛+⎟

⎠⎞

⎜⎝⎛+=

k

rdrdrdt

rtSINSrtCOSCC1

022ππ

ππσ (20)

Where, ttt XX µ−= ~ and tε = sequence of random variables with mean zero and scale tσ

such that { }ttt εσδ 1−= is independent and identically distributed. k= total number of

harmonics, which is equal to 2υ or 2

1−υ depending on whether υ is even or odd,

respectively. the validation of a time series model is tantamount to the application of diagnostic checks to the model residuals to see if they resemble white-noise. to test the white-noise null hypothesis the ljung-box test has used. if the null hypothesis of white-noise residuals is not rejected and if the autocorrelation and partial autocorrelation function of the residuals show no evidence of serial correlation, then we judge the model to adequate. Conclusion In this study, using observation information about “Shahr-chayi” River along with Fourier, Fourier kalman as well as Fourier PARMA models, time series of river flow has been simulated and applied to predict the future flow. Results showed that every three models were strongly applicable in modeling of dynamic time series. Meanwhile, FSAM model due to application of ARIMA model and elasticity of Fourier equation has been located in a higher position rather than ARIMA linear models. In addition, AFAM model was remarkably able to

514


rapidly reduce the errors and improve the results due to application of kalman filter. Also, PARMA (1, 1) model showed a significant accordance with observation information due to application of lower functions. Overall, increasing statistic regarding time series of monthly flows highly develop the applicability of these models in short term predictions in order to be applied in black box modeling.

figure 1: Plot of observed and simulated 60 monthly river flows Data for the “Shahar-chayi” river –Urmia-IRAN References

[1] Tesfaye, Anderson, Meerschart (2007), "Fourier PARMA models and Their Application to River Flows"-Journal of Hydrologic Engineering- ASCE.

[2] Salas,J.D. ,J.W.Delleur.,V.Yevjevich.,W.L.Lane (1998)."Applied Modelling of

Hydrological Time series ", Water Resources Publication.

[3] S.K.Jain, A.Das, D.K.Srivasttava,(1999) "Application of ANN for reservoir inflow

prediction and operation", ASCE journal of Water Research Planning and

Management 25(5).

[4] Rostam Afshar, Fahmi (1996), "Fourier series ARIMA models to rainfall prediction of IRAN", national water organization of IRAN-Annual publication of power Administration.

[5] Pire, Rostam Afshar, "Application of FSAM and AFAM models in rainfall and discharge prediction" , (M.Sc) thesis , Urmia university-Urmia-IRAN.

[6] Box,G.E.P and Jenkins,G.M (1976)."Time Series Analysis Forecasting and Control",2end ed, Holden day , San Francisco.

[7] Wei,W.W.S (1981). "Effect of Systematic Sampling on ARIMA models", Theor & Math.

515


Hydrogeochemistry investigation of karstic sources Khorramabad area, Lorestan province, Iran

T. Dolatsha1, A. Ahmadi-khalaji2, F. Hakimi1, H. Mollaei3, V. Shahrokhi4

1. Islamic Azad University, Khorramabad Branch and member of young researchers club

2- Department of Geology, Faculty of Sciences, University of Lorestan

3. Islamic Azad University, Mashhad Branch

4- Islamic Azad University, Khorramabad Branch

Abstract The studied area lies 33° 25' - 33°33' N and between 48° 15' - 48° 50' E and located in Folded Zagros Zone. The investigation of chemical quality based on chemical analyses different water resources under ground of drinking water in Khorramabad area show that these sources are good quality (with the exceptions of Tir square that have high content Arsenic, 27mg/lit) and suitable for agriculture and drinking consumptions. Lithological exact investigation implies that geology formations in this area different from based on hydrogeology characteristics. The purity percentage of carbonates in upper cretaceous rocks (Bangestan carbonate formation) shows that these rocks have primary and secondary porosity. The primary porosity has low effect of karst formation but secondary porosity is basic factor in karstic formation. So, tectonics conditions and faults are basic influence in karstic bed, caves that was canal for passing ground water. Indeed in parts of dolomitizations occurred, carbonates rocks have high thickness and ground water increase in these beds. Occurrence of different spring to high Debby in these rocks (Motahari, Golestan, Falakedin and Poshte carbonate wells) imply that rocks in this area are mature Karstic. To attention of cap or contact rocks formations (salty- chalky Gachsaran and Asmari) these karstic resources carbonate are damageable of quality for resources water. Key words: Khorramabad, Zagros, karstic, Arsenic, Asmari Introduction Nowadays the access to sweet and safe water is one of great problems for human-beings; therefore, the function of karstic water, which enjoys favorable quality, is undeniably significant in fulfillment of human requirements, and the water resources in our country are considered as strategic richness for our strategic needs, regarding recent droughts. Therefore, due to criticality of karstic resources in supplement of water either for drinking or for culture, also due to vulnerability of these valuable resources against polluting elements, it seems necessary to take the maintenance and preservation of the karstic resources into account. The natural polluting elements, result the geological structure of the area, can be mentioned as the

516


most important elements corresponding to the pollution of karstic water resources. Hence, now the karstic water resources in Khorramabad are studied here. Stratigraphy and geological setting The studied area is located between 48, 15’ & 48, 50’ E, and 33, 25’ & 33, 33’ N (Fig 1). Placing in Zagros Folded Zone geologically (Stocklin, 1968), it has such a normal and balanced condition tectonically (Berthier et al., 1974) that the sediment is aggregated with uniformed stratification according to the age, and there are no particular phenomena excepting the presence of numerous folding and faults in internal parts of formations (James and Waynd, 1965). The emergence of some streams can be corresponding to these sills. The oldest rocks of the area are including limestone, belonging to upper Cretaceous age. The limestone respecting time and place belongs to Bangestan group or it is equivalent of it, and with a sudden contact, it is placed under the Amiran conglomerate. Amiran formation is consisted of two distinct sections in Khorramabad: one is the section of conglomerate with thick stratification called informally Khorramabad conglomerate, because of its rather high development in the area. Another one is the sandstone-shale section, which is from one kind of very tiny – grained calsic shale placed under the Kashkan conglomerate. Kashkan formation, in the age of Paleocene to Eocene is consisted of conglomerate, sandstone and red marl along with layers of limestone in the middle of rocks, whose red marl generally are seen as red soil. Asmari formation in the age of Oligocene to beginning of Miocene is consisted of limestone with tiny texture and including very small and sometimes microscopic holes in the studied area. The limestone is placed under sedimentary units of Fars group in the shape with common slope and with tectonic contact, which is the result of huge fault functions or folding as stalactites and stalagmites. These contacts are particularly important in exchanges and connections of karstic water resources. There are units formed by sandy lime, sandstone, tiny – grained conglomerate, marl, chalk, anhydrite in the age of middle to upper of Miocene on top of Asmari formation. These sedimentary units belong to Fars group regarding the characteristics of the units, as well as, the situation of their settlements upon Asmaric formation. The similarity between the accumulation of sedimentary units and units of Gachsaran formation is rather minuscule; however, it seems more similar to the sedimentary units of Razak formation. Hydrology of the formations Bangestan and Asmari formations are from the most significant formations, being in the area, respecting the amount of their water and the amount of their water output. They are constructed of stony units from limestone and dolomite, and they show their potentiality of forming layers of sweet water, whenever they are changed into karsts, and the holes, breakings, slits and gaps are developed aggregately (White, 1977), but their potentiality is too minute and, they have reduced to be as Shales and the other tiny–grained stones, whenever the rocks are as the form of solidarity without slits and holes, and the dissolvent vessels are not developed in them. The thickness and the development of carbonate rocks are, also, effective in the amount of available underground water in them; therefore, wherever the carbonate rocks have more thickness and regional development, they have more water, and whenever they have less thickness and development, they usually form small water tables. In

517


addition, in some parts where the phenomenon of the development of dolomite and faulting has taken place, the amount of available underground water has increased, because the porosity of carbonate rocks has increased. The upper Cretaceous lime stones (lime Bangestan formation) in Khorramabad area (Khorramabad anticline) from a hydrologic viewpoint have two kinds of primary and secondary porosity, that primary porosity have little impact upon the production of Karst, but their secondary porosity play the greatest role in the production of it, so as the tectonic elements and the faults have a great impact upon the production of the karstic bands and holes and caves in these rocks, which are the place for accumulation and passage of water (Aghasi, 1999). The phenomenon of karstic has developed considerably in lime Asmari formation, because of the presence of great amount of slits and holes and so much porosity especially secondary porosity and there are a lot of outward visible testimonies of karst; this formation has caused the production of underground flowing among the limestone, because of high percentage of carbonate and the vast development of it in the Folded Zagros Zone and rather evolved karst in it. In some parts of the studied area where Asmati formation is covered by salty – chalky formation, it has a great negative impact upon the water resources being in it; however, in the other parts where it is covered by the form from chiefly marl and sandstone, it has less effect upon the quality of Asmari water resources. In addition to the limestone , Amiran conglomerate and Kashkan conglomerate have formed, also, the layers with water in them, whenever they lack complete cement or cement with a lot of holes and slits; however, in the formations whose lithology are chiefly from moraine with chalk , anhydrite , and salt , the amount of water output are weak because of the development of tiny – grained sediment, and the underground water tables are seldom formed in them, which do not have favorable chemical quality and are usually salty. Hydrogeochemical of the water resources Here it is dealt with the determination of physicochemical quality of karstic resources, the effect of geological formations upon the quality of water resources and the determination of the limitation of water consumption both for drinking and culture. The study and analysis of chemical quality of the karstic water resources is dependent upon the chemical results of the last picked up samples of water during the research, some parts of which have been carried out in Lorestan organization of water and the other parts performed by Kermanshah nuclear absorption system. Since the analyses of chemical quality of water have its own complexity, the displaying techniques of qualitative water conditions are used for facilitation to access them. Sholer diagram is used for displaying the condition of drinking and Wilcox diagram is used for displaying the condition of cultural consumption of the area’s water. As mentioned, there are two karstic reservoirs of Asmari formation and Bangestan formation in the studied area. Based upon the chemical results of picked up water samples, the conditions of the studied water have been shown by Sholer and Wilcox diagrams (Fig 2, 3). From drinking viewpoint, they are put from good to acceptable water (Fig 2) and due to having low sodium percentage (%Na) from excellent water and from cultural viewpoint are in the class C2S1 and some C3S1 (Fig 3). PH of the water samples is as the minimum level 7.2 and the optimum of PH 7.4 and the optimum amount of Ion of choler 2.4 mg/lit, and the minimum amount of insoluble solid materials (TDS) are 202 mg/lit, and the maximum of

518


them are 888 mg/lit, which are reduced during the flowing. Total hardness (TH) is, also, as the minimum level 170 and maximum level 332 according to CaCO3. The calculation of the amount of mercury and arsenic in the water samples (except Meidan-e Tir well which has a considerable amount of Arsenic 0.87-4.33 mg/lit), Chrome (5.96-14.15 mg/lit), Copper (0.6-3.97 mg/lit), Zinc (6.97-103 mg/lit) of them are in the standard level and they are not problematic to be drunk. However, the water of Meidan-e Tir well, because of having so much arsenic due to being poisoned by this dangerous element can have hazard for dweller of this part of Khorramabad, so as 0.1 mg of arsenic trioxide can cause people to die. Also, being so much in drinking water and food, this element can cause skin cancer and a lot of kinds of cancers of internal parts of body such as; bladder, kidney, and lung. (Ghazban, 2007). Results There are two karstic reservoirs in the studied area: Asmari reservoirs and Bangestan carbonate unit reservoirs. These carbonate resources and reservoirs are qualitatively vulnerable due to the kind of the covering or contacting formations, in fact, Fars group formation is observed as a polluting, harmful, and adverse formation for area’s karstic water. The water of the area’s wells (excepting Meidan-e Tir well because of high amount of arsenic) has high quality, and does not have any limitation for drinking and cultural uses. References

1- Aghasi, A. (1999). Karst Hydrology. Water engineering standards publishing, 397p.

2- Berthier, F; Billiaul, H.P; Halbroronn, B., Marizot, p., 1974. Etude Stratigraphique, petrologique et structural de La region de khorramabad (Zagros, Iran) - These De 3e cycle, Grenoble, 282.p.

3- Ghazban, F. (2007). Environmental Geology. University or Tehran Press, 440p.

4- James, G.A.and Waynd, J.d (1965) Stratigraphic nomenclature of Iranian Oil Consortium Agreement area. A.A.P.G BULLETIN 49, PP.2182-2245.

5- Stocklin,J .(1968)Structural history and Tectonics of Iran : a review. A.A.P.G.Bulletin, 55, 1229-1258.

6-White, B.W (1977) Role of Solution Kinetics in the development of Karst aquifers .Karst and F .L.Doyle, Alabama, USA.

519


Figure 1: The geographic situation of Khorramabad and the places of the studied area water resources Fig 3: The chemical result of complete analysis of qualitative water resources in Khorramabad, which shows that the water is from good to acceptable from drinking viewpoint.

Acceptable

Good

Bad

Unsuitable

Temporarily acceptable for drinking

Unacceptable for drinking

520


Fig 3: The chemical result of Khorramabad resources which shows that the water is from excellent classes from cultural uses viewpoint respecting having low sodium percentage, placed in classes C2S1 and C3S1.

521


Geoelectrical Exploration for Groundwater in Shooroo Basin, Southwest of Zahedan, Iran

Hadi Tahmasbi nejad, Gholam R. Lashkaripour

Islamic Azad University, Behbahan branch, Tel: 09163720786, [email protected]

Department of Geology, University of Mashhad

Abstract A geophysical survey using the Vertical Electrical Soundings (VES) techniques has been used to investigate the sub-surface layering in Shooroo basin, Southwest of Zahedan in order to determine the nature, characteristics and spatial extent of the components of the aquifer underlying the region, the field data was interpreted using the Russian software IPI7.63. The results of the interpreted VES data suggest that the region consists of four to five layers of topsoil, unsaturated aquifer, saturated aquifer and bed rock. From the viewpoint of geoelectric, aquifer is divided into two separated parts. One with high resistivity in the west especially southwest of basin which thanks to good water quality and coarse grain size (existing alluvial fan) and another with low resistivity specially in the central part, as a result of bad water quality inputted from adjust basin. The average resistivity of top soil, alluvium, aquifer and bedrock calculated in the entire basin are respectively as 110, 87, 27 and 110 Ohm-m, in the east as 70, 74, 12 and 103 ohm- m and in the west as 175, 116, 46 and 106 ohm-m. The depth and thickness of the aquifer were measured in the entire basin as 30 and 30 m, in the east as 23 and 24 m and in the west as 40 and 41 m. In the case study, the relationship between the depth of current penetration and length of current electrodes is obtained. Limitation of aquifer, depth of aquifer in entire basin, and isopize groundwater map to be obtained from geoelectrical survey, also zones with high yield potential have been determined. Key Words: exploration, Groundwater, Vertical Electrical Soundings (VES), Shooroo basin. Introduction Shooroo basin is located in Southwest of Zahedan and between longitudes of 60 50 to 20 12 (fig. 1). Average of annual rainfall in Shooroo basin is 84 millimeter and its climate is dry (using Demarton method), and intense hot (using Amberger method).

Fig.1. Location of investigation and sounding data

225000 230000 235000 240000 245000

3215000

3220000

3225000

3230000

a1 a2 a3 a4 a5 a6 a7 a8

b1b2b3b4b5b6

c1 c2 c3 c4 c5 c6 c7 c8 c9 c 10

d1d2d3d4d5d6d7d8d9d 10d 11d 12

e1 e2 e3 e4 e5 e6 e7 e8 e9 e 10 e 11 e 12 e 13 e 14 e 15 e 16 e 17 e 18

f1f2f3f4f5f6f7f8f9f10f11f12f13f14f15f16f17f18f19f20f21

g1 g2 g3 g4 g5 g6 g7 g8 g9 g 10 g 11 g 12 g 13 g 14 g 15 g 16 g 17 g 18 g 19

h1h2h3h4h5h6h7h8h9h 10h 11h 12h 13h 14h 15h 16h 17h 18h 19h 20h 21

i1 i2 i3 i4 i5 i6 i7 i8 i9 i10 i11 i12 i13 i14 i15 i16 i17

j1j2j3j4j5j6j7j8j9j10j11j12j13j14j15

k1 k2 k3 k4 k5 k6 k7 k8 k9 k 10 k 11

l1l2l3l4l5

m1 m2 m3 m4

ee0ee1ee2ee3ee4

d d0 d d1 d d2 d d3 d d4

cc0cc1cc2cc3cc4cc5cc6

b b7b b6b b5b b4b b3b b2b b1b b0

aa7aa6aa5aa4aa3aa2aa1aa0

a a 0a a 1a a 2a a 3a a 4a a 5

4

4shoo roo

Haji a bad 1

M oha mmad a bad

Haji a bad 2

Galoo gah

Kashi lkiPelki

Neama t a bad

Out line

T oward ko orin

Towar d Doomak

0 2000 4000 6000

( m)

522


Geological Setting From the view point of geology and structural geology, Shooroo basin is located in Flysch zone of Eastern Iran. In this zone, sediments of older than cretaceous are absent, mountains direction is north-south and more numerous Flyshes were metamorphic (McCall, 1997). Approximately entire area has been covered by Slats mainly green as upper Cretaceous age and partly, Eocene too. In west part of watershed were observed intermediate of Phylit and Sandstone. Quaternary alluviums that has covered plain surface were involve to fine grain alluvium of Shooroo river and drainage’s, gravel to pebble of alluvial fan and too sand to gravel’s of near the mountains. Introduction Surface geophysical survey as a veritable tool in groundwater exploration, has the basic advantage of saving cost in borehole construction by locating target aquifer before drilling is embarked upon (Obiora and Ownuka, 2005). Vertical electrical sounding (VES) is a geoelectrical common method to measure vertical alterations of electrical resistivity (Heilan, 1940). Also, schlumberger array is found to be more suitable and common in groundwater exploration. It is well known that resistivity methods can be successfully employed for ground water investigations, where a good electrical resistivity contrast exists between the water-bearing formation and the underlying rocks (Zohdy et al., 1974) In general, VES method with Schlumberger array assumes considerable importance in the field of ground water exploration because of its ease of operation, low cost and its capability to distinguish between saturated and unsaturated layers. Thus this technique has been used in case study. This method is generally used to solve a wide variety of groundwater problems. such as determination of depth, thickness and boundary of a aquifer (Bello and Makinde, 2007; Omosuyi, 2007; Ismail Mohamaden, 2005), determination of zones with high yield potential in a aquifer (Akaolisa, 2006; OSEJI, 2005), determination of the boundary between saline and fresh water zones (El-Waheidi, 1992; Khalil, 2006), delineation groundwater contamination (Kelly, 1976; Park et al., 2007), Exploration of geothermal reservoirs (El-Qady. 2006), estimation of porosity of aquifer(Jackson et al., 1978), estimation of hydraulic conductivity of aquifer (Asfahan, 2007; Yadav, 1995) estimation of aquifer transmissivty (Kosinski and Kelly, 1981) and estimation of aquifer specific yield(Frohlich and Kelly, 1988). The electrical resistivity technique enables the determination subsurface resistivity by sending an electric current into the ground and measuring the potential field generated by the current. The depth of penetration is proportional to the Schlumberger array uses closely spaced potential electrodes and widely spaced current electrodes. Separation between the electrodes in homogeneous ground and varying the electrodes separation provides information about the stratification of the ground (Dahlin, 2001). However, in general, the depth of infiltration is small in this method, and only shallow subsurface layers have been surveyed (Danielsen et al., 2007). For soundings, the apparent resistivity values (ρa) were plotted against half current electrode separation on a log-log graph and a smooth curve was drawn for each of the soundings. Then, the sounding curves were interpreted to determine the true resistivities and thicknesses of the subsurface layers.

523


aà`5

aà`4

aà`3

aà`2

aà`1

aà`0

36

59

43

75

51

51

108

45

26

47

85

117

4

10

12

15

22

9

126

41

40

48

108

133

40 41

154

64----9.5162----- -1524

314

50

154

120-----486

168-----525

80----1022

6059110

425

152

151

82

192

148

180

1540

1520

1500

1480

1460

1440

1420

1400

1380

0Horizontal Scale:

200 400 800 600

Geoelectrical resistivity survey Geoelectrical survey of Shooroo basin was involve 207 vertical electrical sounding by Schlumberger array and 19 profiles (profile spacing was 1 kilometer) that sounding spacing was 750 m and direction of total profiles was East-West (Fig. 1). For Schlumberger soundings, the apparent resistivity values were plotted against half current electrode separation (AB/2) on transparent double log graph paper and a smooth field curve was drawn for each of the soundings. The field curves were interpreted by the well-known method of curve matching with the aid Russian software IPI7.63. The key to success of any geophysical survey is the calibration of the geophysical data with hydro geological and geological ground truth information. Therefore, a number of geoelectric stations were purposely located near about 70 wells so that litologic information obtained from log could be used to calibrate the V.E.S field curves. Where test hole-log information was available, the solution to automatic interpretation procedure was constrained by keeping known layer thickness constant during the program computations. The result of Schlumberger soundings have been compared with the geoelectrical sections obtained from 13 Pizometer. These results are in good agreement whit the geological sections. Results and discussion At the test sites, one type of sounding curve was observed that a four-layer curve resulted from a four-layer section consisting of topsoil, unsaturated aquifer, saturated aquifer and bed rock. In some cases more than one layer was evident in the saturated zone but these cases were also treated in this analysis as single layers. Depth and thickness of subsurface layers were identified and dimension of the aquifer and type of bedrock were indicated. Bedrock of area is generally Slat but in some parts is appeared as Shale. Geoelectrical section of profile aà` has been shown in figure 2, for example.

Fig. 2. The geoelectrical section of profile aà` Two separate parts is identifiable in the east and the west parts of basin. The average resistivity of top soil, alluvium, aquifer and bedrock respectively calculated in the total basin as 110, 87, 27 and 110 Ohm-m, in the east as 70, 74, 12 and 103 ohm- m and in the west as

524


175, 116, 46 and 106 ohm-m. Depth and thickness of the aquifer were measured in entire basin as 30 and 30 m, in the east as 23 and 24 m and in the west as 40 and 41 m. These are obtained in the west part due to existence alluvial fan and in the other due to bad water quality inputted from adjust basin. Yield potential in the west part of basin is more than another part and profile ee has the most of yield potential and the best of water quality with respect to high thickness and resistivity. The geoelectrical model of subsurface layers indicates average of resistivity and thickness of layers is shown in Fig.3.

Fig.3. The geoelectrical model of subsurface layers. Also, for example, interpreted curve of sounding aa5 by software IPI7.63 is shown in Fig.4.

Fig.4. Typical interpreted VES curve from study area (sounding aa5).

After the interpretation, depth of current penetration in plain was calculated (Fig.5), as:

970

2570 .)AB(.Depth =

This relation present current penetration depth in plain equal Approximately4

AB .

Alluvium

Top Soil

Aquifer

Bed Rock

R=110 Ohm-mT=11 m

R=87 Ohm-mT=19 m

R=27 Ohm-mT=30 m

R=110 Ohm-m

525


225000 230000 235000 240000 245000

3215000

3220000

3225000

3230000

4shooroo

Haji abad 1

Mohammad abad

Haji abad 2

Galoogah

KashilkiPelki

Neamat abad

Out line

Toward koorin

Toward Doomak

0 2000 4000 6000(m)

Fig.5. relation of depth of current penetration with length of current electrodes Fig. 6 shows isopize groundwater map to be obtained from geoelectrical survey that represents inflow and outflow of aquifer. Limitation of aquifer and type of bedrock were indicated. Bedrock of area is generally Slat and at some points has appeared as Shale.

Fig. 6 Isopize groundwater map (obtained of geoelectrical survey) Conclusions The geoelectric investigations showed that there are four geoelectric layers correspond to near-surface layers, dry alluvium, aquifer and bedrock. Aquifer has different resistivity values that respect to its water quality and its component grain size. Also bedrock show different resistivity values with respect to degree of saturation and values of fracture. In the west part of plain, yield potential and water quality is more than another part.Limitation of plain has been estimated profile e in Sought-East profile a`a` in Northwest and mountains in North.

y = 0.5666x0.9706

R2 = 0.8364

0

50

100

150

0 25 50 75 100 125 150 175 200

AB/2 (m)

Dep

th(m

)

526


Reference

[1] Akaolisa, c., 2006. Aquifer transmissivity and basement structure determination using resistivity sounding at Jos Plateau state Nigeria. Environmental monitoring and assessment., 114: 1-3.

[2] Apparao, A., Rao, T.G., 1974. Depth of investigation in resistivity methods using linear electrodes. Geophysical Prospecting 22: 211-223.

[3] Asfahan, J., 2007. Neogene aquifer properties specified through the interpretation of electrical sounding data, Salamiyeh region. central Syria. Hydrological Processes, 21: 2934 – 2943.

[4] Bello, A. A., Makinde, V., 2007. Delineation of the Aquifer in the South-Western Part of the Nupe Basin, Kwara State, Nigeria. Journal of American Science, 3(2): 36-44.

[5] Dahlin, T. (2001) The development of DC resistivity imaging techniques. Computers Geosciences, 27: 1019-1029

[6] Danielsen, J., Dahlin, T., Owen, R., Mangeya, P. and Auken, E., 2007. Geophysical and hydrogeologic investigation of groundwater in the Karoo stratigraphic sequence at Sawmills in northern Matabeleland, Zimbabwe: a case history. Hydrogeology Journal, 15(5): 945-960.

[7] Darvishzadeh, A., 1981. Geology of Iran. Nacre ermine (in Persian.

[8] El-Qady. G., 2006. Exploration of a geothermal reservoir using geoelectrical resistivity inversion: case study at Hammam Mousa, Sinai, Egypt. J. Geophys. Eng., 3: 114-121

[9] El-Waheidi, M. M., Merlanti, F., and Pavan, M. 1992. Geoelectrical resistivity survey of the central part of Azraq basin (Jordan) for identifying saltwater/freshwater interface. J. Applied Geophysics, 29: 125-133.

[10] Frohlich, R. K. and Kelly, W. E., 1988. Estimates of specific yield with the geoelectrical resistivity method in glacial aquifers. J. Hydrol., 97: 33-44.

[11] Frohlich, R. K., and Parke, C. D., 1989. The electrical resistivity of vadose zone–field survey. Groundwater., 27 (4): 524-530.

[12] Heilan, C. A., 1940. Geophysical exploration. Prentice Hall, NewYork, N.Y.

Ismailmohamaden, M. I., 2005. Electric resistivity investigation at Nuweiba Harbour Gulf of Aqaba, south Sinal, Egypt. Egyptian journal of aquatic research Issn, 31: 1110-0354.

[13] Jackson, P. N., Taylor Smith, D., and Stanford, P.N., 1978. Resistivity-porosity-particle shape relationships for marine sands. Geophysics, 43(6): 1250-1268.

[14] Kelly, W. E., 1976. Geoelectric sounding for delineating ground water contamination. Ground Water, 14(1): 6-11.

[15] Khalil, M. H., 2006. Geoelectric resistivity sounding for delineating salt water intrusion in the Abu Zenima area, west Sinai, Egypt. J. Geophys. Eng., 3: 243-251.

[16] Kosinski, W. K., and Kelly, W. E. 1981. Geoelectric sounding for predicting Aquifer Properties. Ground Water, 19(2): 163-171.

[17] MCCALL, G.J.H. (1997): The geotectonic history of Makran and adjacent area of Southern Iran, J. Asian Earth Sci., 15, 517-531.

[18] Obiora, D.N. and Onwuka. O.S., 2005. Groundwater exploration in Ikorodu, Lagos-Nigeria: a surface geophysical survey contribution. The pacific journal of science and technology, 6(1): 86-93.

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[19] Omosuyi, G.O., Adeyemo, A. and Adegoke. A.O., 2007. Investigation of Groundwater Prospect Using Electromagnetic and Geoelectric Sounding at Afunbiowo, near Akure, Southwestern Nigeria. The pacific journal of science and technology, 8(2): 172-182.

[20] Oseji, J. O., Atakpo, E. A., Okolie, E. C., 2005. Geoelectric investigation of the aquifer characteristics and groundwater potential in Kwale, Delta state, Nigeria. J. Appl. Sci. Environ. Mgt., 9(1): 157 – 160.

[21] Park, Y. Doh, S. and Yun, S., 2007. Geoelectric resistivity sounding of riverside alluvial aquifer in an agricultural area at Buyeo, Geum river watershed, Korea: an application to groundwater contamination study. Environmental geology journal, 53(4): 849-859.

[22] Yadav, G. S., 1995. Relating hydraulic and geoelectric parameters of the Jayant aquifer, India. Journal of Hydrology, 167: 23-38.

[23] Zohdy, A.A.R., G. P. Eaton, and D. R. Mabey., 1974. Application of surface geophysics to ground-water investigations. D1. U.S. Geol. Surv. Techn. Water Res. Invest., 116pp.

528


OLAP Methods for EQ Alarm Systems Design

Vladimir Prelov

Russian Academy of Sciences, Mechanical Engineering Research Institute,

Maliy Kharitonievskiy per., 4, Moscow 101990 RUSSIA, 7(495)624-9800. Email: [email protected]

Abstract In our paper we present a set of OLAP and Data Mining opportunities to solve well known problem of the seismic shocks forecasting. As known, the three of parameters such as time, magnitude, location are integrated in this problem and if any of them can not be forecasted well, the total forecast can not play the role of the warning. Our goal is to discuss the points concerning the development of the EQs early alarm reliable systems on the basis of modern IT opportunities spectrum we have briefly mentioned in [1-7]. Any creative techniques to solve the problem have both advantages and weaknesses plus some limitations to be applied. The most effective way to increase the reliability of the EQ alarm systems is a strong collaboration between long-, medium- and short-term techniques of forecasting and, as well, the interdisciplinarity of the research methods. We present a set of such tools for EQ events forecasting developed on the basis of the ultra-long data series (up to 60 GB) collected at the Russian Far East IRIS stations of Kamchatka. As widely known, it is extremely difficult to guess the location of coming EQ with precursors recorded at only one seismic station. However, we noticed a high degree of correlation exists at the Efficiency and the Entropy precursor curves corresponding to EQs occurring in the same location but at different times, even if the magnitudes of the events were different [1-3]. We present and discuss both some general practical (Fig.1, 2) and theoretical (Fig.3, 4) results obtained with analytical processing of huge data arrays mentioned above we usually deal with in geophysics. It was noticed, verified and proved, the existence of asymptotically stable limit value for the Efficiency connected with both the Maxwell-Boltzmann and Shannon entropies (Fig.4, 5). We present the thermodynamical way to get the explicit value of the parameter and discuss the wide spectrum of geophysical applications of the phenomenon. Some Entropy methods developed recently by us to study the crisis events [4-7] can be fruitfully applied to solve the short-term EQs forecasting problem (Fig.6-9). We present a creative spectral distance method for ultra-long data series processing to explain EQ short-term forecasting algorithms (Fig.4, 7, 9). Finally, we discuss some opportunities to solve the seismic shock/fore-shock identification problem on the basis of the USGS NEIC series processed for the 30-Y period (Fig.10). Wide spectrum of the IT ideas for reliable EQ alarm systems is presented.

529


REFERENCES

1- Prelov, V.V., 2009, Data Mining and Crisis Forecasting Opportunities: ISSN-1941-9589, v.4, No.2, pp. 60-64.

2- Prelov, V.V., 2009, On the Efficiency Theorem: ISSN-1941-9589, v.4, No.2, pp. 88-91.

3- Prelov, V.V., Makhutov, N.A., 2004, Descriptorial Analysis of the Crisis Syndromes:

Safety and Emergencies Problems, v. 4, p. 11-17 (in Russian).

4- Prelov, V.V., 2009, Large Systems Theory and Geophysical Monitoring: Problems for Complex Geophysical Monitoring of the Russian Far East. Russian Academy of Sciences, Far East Branch, p. 38 (in Russian).

5- Prelov, V.V., 2009, Seismic Data-flow Analysis and the EQs Short-term Forecasting Problems: Problems for Complex Geophysical Monitoring of the Russian Far East. Russian Academy of Sciences, Far East Branch, p. 92 (in Russian).

6- Prelov, V.V., 2009, Data-mining for Seismic Statistics – Unexpected Relationships to Global Physical Constants: Problems for Complex Geophysical Monitoring of the Russian Far East. Russian Academy of Sciences, Far East Branch, p. 93 (in Russian).

7- Prelov, V.V., 2009, Data-mining and the Main-Shock Forecasting Opportunities: The IV-th Russian Symposium on volcanology and paleovolcanology. Russian Academy of Sciences, Far East Branch, p. 659 (in Russian).

FIGURES

Fig.1. FFT for 1997 Kronotskoe EQ (5-days spectrum before the event).

Fig.2. FFT for 1997 Kronotskoe EQ (4.5-days spectrum before the event).

530


Fig.3. Efficiency surface for making-decisions (normalized over the unit cube).

Fig.4. Relationships with fundamental physical constants for making-decisions.

Fig.5. Global EQs distributions since 1971 by the moment and Fibonacci numbers.

3820,0~1 Φ−=ϕ 3822,0/ 5.45.4 =<> NN

37817755.0)1(

1 2

≈+

+=

eeeE ϕ

eE

eE=

−−

ϕ/1

,1 Φ−=ϕ2

15 −=Φ

531


Fig.6. Global EQs distributions since 1971 step-by-step.

Fig.7. Semi-log scale for Magnitude-EQs (USGS NEIC) equations (with R^2~1).

Fig.8. Semi-log chart for Magnitude-EQs (USGS NEIC) Fibonacci events forecasting.

532


Fig.9. Right-hand side of Fig.8. for Fibonacci events forecasting (with R^2~1).

Fig.10. Global EQs distributions over the latitudes and Fibonacci law of the 2-nd order.

4370,0~2/2Φ=φ)/arcsin( nkk =α ,

k=1…n, ∞→n 4375,0=ρ

533


Crustal modeling in the Naeen region

Z.S. Riazi Rad

Islamic Azad University, Chalus branch [email protected]

Abstract This study, joint inversion method of body waves and receiver function, has been investigated. At first body waves recorded in broadband Naein station, have been analyzed with one station and two station methods. Therefore, travel time curves and body wave velocities of crust and upper mantel indicated. These method-calculated depths of Moho discontinue (40 km). The receiver function method has been divided upper, middle and lower crust. Upper, middle and lower crust thickness is 14 km, Vp=3.9-4.6 km/s, h=6 km, Vp=4.8-5.9 km/s and h=19km, Vp=3.7-4.6 km/s. depth of Moho discontinue with joint inversion calculated 38km. this method show two layers (upper and lower crust). Vp=6.2-6.7 km/s, Vs=3.6-3.7 km/s and h=12km in upper crust and Vp=6.7-8.01 km/s, Vs=3.7-4.6 km/s and h= 26km. The crustal velocity coincides with the region of high seismic activity, which indicates that the crustal anomaly is related to active tectonic processes. Keywords: Modeling, Crust, joint inversion, Central Iran Introduction The problem of data-driven velocity model building for depth-imaging applications is approached from the point of view of simultaneous joint inversion of separate geophysical domains. For this purpose, a general formulation of the joint inversion problem is provided. The method is then applied to a real (long offsets) seismic dataset from Central Iran where seismic refraction travel-time residuals (first-break and Common Image Gather residuals) are jointly inverted with receiver function for improving velocity model building and the corresponding depth-domain seismic image. Effective depth imaging through migration can be achieved only if a precise estimate of interval velocity in depth is available. The definition of a reliable velocity model for depth imaging is a difficult task especially when sharp lateral and vertical velocity variations are present. The problem becomes even more serious when the seismic refraction data are noisy giving little chance to extract useful velocity information from the data. Geologic models can provide a guide to the velocity model building and data integration with other geophysical methods can also be extremely important. Several different approaches to geophysical data integration were proposed in the past but in a very few cases the data integration problem has been handled in terms of simultaneous joint inversion of geophysical data. No applications to date, however, attempted the simultaneous joint inversion of non-seismic geophysical data and pre-stack seismic migration residuals for the improvement of seismic images in depth domain.

534


Formulation of the Joint Inverse Problem The conversion of one elastic wave, either P or S, into another upon reflection or transmission at an interface is described by the Zoeppritz equations. These equations are algebraically quite complex and it is not practical to reproduce them here.

α∆α

iρ∆ρPPN

2cos2

124121

+⎟⎠⎞⎜

⎝⎛ −=

ββ

αβββ

ρρ

αβββα ∆

⎟⎟⎠

⎞⎜⎜⎝

⎛−−

∆⎟⎟⎠

⎞⎜⎜⎝

⎛+−−=

jiPjiPj

PRF coscos44coscos221cos2

2222

Instead, we will present useful concepts and approximate forms. Since there are four possible incident waves, upcoming, downcoming P, S, and four possible scattered waves, upgoing, and downgoing P and S, sixteen scattering coefficients link them. The normal incidence PN can be written in other suggestive ways. If we define the impedance contrast ∆I=I2-I1, and the average impedance I=(I2+I1)/2 , then PN=0.5∆I/I. Going further, since P-wave impedance is the product of density, ρ , and P-wave velocity, α, it turns out that PN=.5(∆α/α+∆ρ/ρ). The ratios in the parenthesis are called the P-wave velocity fluctuation, ƒα=∆α/α, and the density fluctuation, ƒρ=∆ρ/ρ, so that PN=.5ƒα+.5ƒρ. This suggests the very useful Colombo approximation that PN≈Cαƒα+Cρƒρ+Cβƒβ. Here ƒβ is the S-wave velocity fluctuation and the coefficients Cα, Cρ, Cβ depend upon the P-wave and S-wave incidence and refraction angles and the average αβρ but not upon ∆α∆β∆ρ. Comparing the normal incidence form of PN to the Colombo approximation shows that, for an incidence angle of 00, Cα=Cρ=.5 and Cβ=0. So at normal incidence, PN carries information about fα and fρ in equal amounts and nothing at all about fβ . This situation changes as we move to nonzero offset and Cα, Cρ, Cβ depart from their normal values of (.5,.5,0). If we let θdenote the average of the P-wave angles of incidence and transmission and φbe the average of the S-wave angles of reflection and transmission, then the variation of Cα, Cρ, Cβ with offset can be represented either as dependence on θor upon φsince these angles are related by Snell’s law. In addition, Cρ, Cβ are not independent of one another in fact Cρ=.5+.5Cβ. Precisely how these coefficients vary depends upon the specific values of the elastic constants. These cases are idealized examples of the regional and reservoir behavior, at the stratigraphic level of the top of the channel, in the Blackfoot field. In both reservoir and regional settings, the fluctuations fα ,fρ ,fβ have the same sign with αand ρ decreasing while βincreases. However, the magnitude of these changes is much great in the reservoir case. Figure 1 shows the behavior of of Cα,Cρ,Cβ for both the reservoir and non-reservoir cases. Colombo also provides an approximate form for the refraction coefficient for a P-wave converting to and S-wave as RF≈dβƒβ+dρƒρ. As before, the coefficients dβ, dρ depend upon either the P-wave angle θor the S-wave angle φand the average (background) elastic parameters. As with the P-wave case, the density and S-wave coefficients are not completely independent though the relation between them is more complicated: dρ=-sin θ/(2cosφ)+.5dβ. Figure 2 shows the behavior of dβ ,dρ versus P-wave incidence angle and, again, the curves change very little from the regional to the reservoir scenario.

535


Figure 1. The coefficients Cα, Cρ, Cβ of the Colombo approximation PN≈Cαƒα+Cρƒρ+Cβƒβ are shown as a function of the incidence angle.

Figure 2. The coefficients dβ ,dρ of the Colombo approximation RF≈dβƒβ+dρƒρ are shown versus P-wave azimuth angle.

That is, fαcan be estimated, in principle, by an equation of the form

∑ ∑+=k k

kka RFbPNaf )()( θθ

With similar equations, having different weighting functions, for fβ , fρ. In this equation, the sum is over all available offsets and the weights, αθk , are known functions of the background velocity and the incidence angle for the kth offset and b(θk) are the weights for the receiver function data. Similar equations, with different weights, will estimate fβor fρ. The weights for the PN refraction data α θk in these expressions are generally quite different from the analogous weights in the inversion using PN data alone. Seismic data were initially processed in time domain using well-established techniques such-as tomographic static calculation (i.e. tomostatics), multi-window deconvolution and state-of-the-art residual statics and denoising algorithms. The pre-processed data were then provided for the depth-imaging phase. Receiver function data were processed in a robust and fairly standard processing approach involving (among others) the calculation of terrain corrections to a suitable distance (e.g. 40km) from the measurement points. A grid-based model parameterization was adopted. The seismic velocity and density grids were different allowing larger model cells for the receiver function method for deeper layers

536


and by allowing additional lateral padding in the density model for taking into account border effects. Figure 3 shows the result of a simple series of experiments on synthetic data from a single interface. The full Zoeppritz equations were used to generate exact PN and RF. In a noise-free case, both P inversion and joint PN and RF inversion produce identical estimates of the fluctuations. However, when random noise was added to the PN and RF values, the joint method becomes clearly superior. The simplest reason for this is that both methods constrain the same number of unknowns but the joint method uses twice as much data. This is much greater statistical leverage. As this figure shows, the fJ estimates are most dramatically improved in the joint inversion and that leads to better estimates of the pseudo-Poisson’s ratio fluctuation fI fJ. FPJI - Joint Inversion Workflow The velocity model building was performed since the first iteration by applying the simultaneous joint inversion of seismic refraction and receiver function data. This provided a long wavelength solution of the velocity field ranging from detailed velocity determinations to macro-velocity determinations for the model section below the maximum penetration of the long offset turning rays. The receiver function method was critical at this stage in extrapolating the velocity determinations to depth. Further refinement of the velocity model for depth migration was performed by interpreting geologically consistent horizons, determining post-migration residuals along them and performing joint inversions in conjunction with receiver function. The horizon-based joint inversion proceeded in a layer stripping approach from top to bottom of the model (figure 4).

Figure 4. Velocity model building through Joint Inversion of seismic refraction and receiver function data, Central Iran.

Conclusions The Joint-Inversion velocity model building workflow shows various advantages over traditional approaches. Some of these are:

537


1) The simultaneous use of receiver function data with seismic refraction provides extended depth resolution to what can be achieved from the use of the first breaks alone: from the first iterations one can solve for the macro velocities describing the whole model. 2) Receiver function data are equally sensitive to low and high density distributions whilst turning rays are more sensitive to high-velocity zones. This means that seismic refraction-receiver function joint inversion is able to retrieve near surface velocity inversions that would not be obtained by first break tomography alone. 3) The inversion problem becomes less non-unique and converges more rapidly toward the correct solution (velocity model building takes many less iterations and it is more reliable). Acknowledgements The author acknowledged IIEES (International Institute Earthquake Engineering and Seismology) of Iran, for providing the necessary data for this research. We thank Indago Petroleum Ltd and Ministry of Oil and Gas, Oman for allowing the publication of the real data application. References

- Galve, A., Sapin, M., Hirn, A., Diaz, J., lepin, C., Laigle, M., Gallart.J., 2002. Complex images of Moho and variation of Vp/Vs across the Himalaya and Sounth Tibet, from a joint receiver function and ide angel reflection approach: J. Geophys. Res., no. 29, p. 2182-2186.

- Colombo, D., Mantovani, M., De Stefano, M., Garrad, D., and Al Lawati, H., 2007. Simultaneous joint inversion of seismic refraction and receiver function depth Migration in Northern Oman: Departement of Earth and Atmospherics Sciences, Saint Louis University, Sponsored by DSWA, Contract No. DSWA 01-100-c0160.

- Julià, J., Ammon, C.J., and Herrmann, R.B., 2003. Lithospheric structure of the Arabian Shield from the joint inversion of receiver functions and surface wave group velocities: Tectonophysics, no. 371, p. 1–21.

- Hu, J., Zhu, X., Xia, J., Chen, Y., 2005. Using surface wave and receiver function to jointly inverse the crust–mantle velocity structure in the West Yunnan area: Chin. J. Geophys, no. 48, p. 1069–1076.

- Chang, S., and Baag, C., 2005. Crustal structure in Southern Korea from joint analysis of teleseismic receiver functions and surface-wave dispersion: BSSA no. 95, p. 1516–1534.

nonlinear site response evaluation procedure under the

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