research article excellent performance of earth dams under
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Research ArticleExcellent Performance of Earth Dams under ResonanceMotion Using Isolator Damping Layer
Behrouz Gordan and Azlan Adnan
Engineering Seismology and Earthquake Engineering Research Group (e-SEER) Universiti Teknologi Malaysia81310 Skudai Johor Malaysia
Correspondence should be addressed to Azlan Adnan azlanadnanutmmy
Received 20 February 2014 Accepted 22 April 2014 Published 22 May 2014
Academic Editor Alicia Gonzalez-Buelga
Copyright copy 2014 B Gordan and A Adnan This is an open access article distributed under the Creative Commons AttributionLicense which permits unrestricted use distribution and reproduction in any medium provided the original work is properlycited
The effect of blanket layer using isolator damping layer (IDL) between river sand foundation and short embankment to removedamage under severe earthquake was investigated in the present study In case of numerical analysis by ANSYS program dominantfrequency (DF)was computed by free vibration analysis Soilmechanic tests for thirteen samples to design IDL formulawere carriedout In terms of critical condition for earthquake effect such as resonance five physical small models were tested using vibrator tableunder the dominant frequency with scale parameter 1100 As a result dam was significantly damaged without blanket layer IDLIn order to reduce damage the best performance was observed using blanket layer (IDL) when this layer was expanded below thereservoir region The reinforced thickness layer size is one-fourth of dam height This method is a novel suggestion for earth damdesign in seismic zone
1 Introduction
The dynamic assessment dramatically has been started inearth dams after the observation of some damages duringthe earthquake In this domain huge damage such as bodycracks was recorded Totally this knowledge is correspon-dent to control dam behavior to avoid of failure processBesides earth dam construction is possible with respect tocompaction process Therefore the consolidation settlementcan be completely maximized at the end of construction Interms of earthquake effect on dam response the first phaseof total settlement is related to the final displacement in thestatic state Therefore total settlement is the superposition ofstatic and dynamic effect According to literature review inthis study a few cases of data monitoring was just recorded[1ndash3] Two cases such as the lack of data monitoring andtechnological development to provide computing programled to use of numeric method for dynamic analyzing Inthe other words the numerical analysis was commonlyutilized in several studies to predict dynamic behavior duringthe earthquake [4ndash9] In terms of analysis technique two
methods such as finite-element method (FEM) and finite-difference method (FDM) can be applied Dynamic analysisof earth dam was carried out by using two techniquessuch as two-dimensional and three-dimensional [10ndash13] Toselect plane strain (2D) and plane stress (3D) depends ondam configuration and valley shape in order to distributelateral strain [14] In terms of reinforcement methods somemethods have been used to reinforce dam in order to improvedynamic behavior along the earthquake [15ndash19] To verifyresults based on numeric analysis both tests such as shakingtable and centrifuge were successfully experienced [20ndash22]However to avoid dam failure by earthquake the effect offoundation soil was of a significant role to generate crackswith respect to increase of acceleration and displacementat the crest In the present study the main purpose is theimprovement of dam performance under severe motion likeresonance condition using blanket layer between foundationand homogenized earth dam In other words this paperpresents a novel method to remove damage by using newmaterial (IDL) In order to discuss level of damage in damfive physical models in regard to dominant frequency will
Hindawi Publishing CorporationShock and VibrationVolume 2014 Article ID 432760 15 pageshttpdxdoiorg1011552014432760
2 Shock and Vibration
be vibrated To improve dam performance the optimumthickness will be finally suggested
2 Laboratory Soil Tests
Two types of experimental tests were carried out in thisstudy Firstly soil mechanic tests were performed based onBritish Standard (BS) in order to design isolator dampinglayer (IDL) Secondly some small scale models with respectto finding the best location to reinforce dam were vibrated byusing vibrator table In terms of soil characters the BritishStandard (BS) for soil mechanic tests was used Based onsoil classification the local laterite soil MH was applied Thesummarizing of laterite properties is illustrated in Table 1 asused in this study
The passing percentage for different materials such aslaterite tire derived aggregate (TDA) and microsilica (MS)was shown in Figure 1 The determination of particle sizedistribution was carried out by using BS 1377-2 1990 Thisfigure shows that the amplitude of material size was locatedbetween 0075mm and 200mm Based on specific gravitytest this value forMSwasmore than TDAThese values wererespectively exposed at 242 and 215 Table 2 shows sampleswith respect to different mixtures to design IDL
According to soil laboratory test undrained shearstrength in the triaxial compression without measurement ofpore pressure (quick undrained) indicated that the strain insamples is increased by using more percentage of TDA it canbe observed in Figure 2 Also in this figure elasticitymodulusis reduced (see histograms in Figure 3) Significantly theyield point was dramatically reduced in this trend Withrespect to increasing flexibility by using maximum TDAfailure stress is possible with lower value Figure 3 showsthat the increase of TDA has effectively led to decrease ofelasticity modulus that was obtained with 9021 for sample5 In fact the elasticity modulus was significantly decreasedby using 10 TDA as mentioned previously Moreover themaximum and minimum values of modulus elasticity wererespectively obtained in sample 1 and sample 5 as can be seenin Figure 4 It is worth noting that the regular increase of themodulus was just found in sample 4 by increase ofmicrosilicawith 7 of TDA (see Figure 5 histogram without filling)In terms of flexibility distribution in samples the maximumand minimum value of the area below curve were located insample 8 and sample 5 as shown in Figure 6 In addition thegood convergence for sample 9 and sample 1 was obtainedIt should be noted that the quick undrained results werecomputed by average from three cases After all flexibilityfactor has the important role in order to absorb energy
According to consolidation test themaximum coefficientof volume compressibility was located in sample 6 with 0207while the minimum value was in sample 13 with 0081 (seeFigure 7(a)) It was revealed that the increase of TDA forsamples 1 to 5 caused increasing of rate regardless of sample 2In fact this coefficient was double value for sample 5with 10TDA In addition the minimum value was observed by 10TDA with 4 silica (see sample 12) Also in Figure 7(b) themaximum and minimum coefficient of consolidation were
Table 1 Characteristics of the laterite soil
Physical properties ValueSpecific gravity 240Liquid limit LL () 75Plastic limit PL () 41Plasticity index PI () 34BS classification MHMaximum dry density (g cmminus3) 133Optimum moisture content () 35Unconfined compressive strength (KPa) 30626Cohesion (KPa) 2518Angle of internal friction (degree) 3000Modulus elasticity (KPa) 1528372Coefficient of volume compressibility (mv m2MN) 01055Coefficient of consolidation (cv m2yr) 4416Permeability (cmseconds) 129119864 minus 5
Table 2 Sample definition
Sample number Component1 Laterite2 Laterite + 3 TDA3 Laterite + 5 TDA4 Laterite + 7 TDA5 Laterite + 10 TDA6 Laterite + 3 TDA + 2 silica7 Laterite + 3 TDA + 3 silica8 Laterite + 5 TDA + 2 silica9 Laterite + 5 TDA + 3 silica10 Laterite + 7 TDA + 3 silica11 Laterite + 7 TDA + 4 silica12 Laterite + 10 TDA + 4 silica13 Laterite + 10 TDA + 5 silica
respectively observed in sample 6 and sample 10 This factorwas progressively reduced by more percentage of TDA andsilicaTherefore the impact of silica to decrease consolidationcoefficient was greater than TDA
It should be noted that the determination of the one-dimensional consolidation properties based on BS 1377-51990 was carried out All samples were tested by using loadssuch as 25 50 999 19980 39970 and 7994 Kilo Pascal Inaddition in order to evaluate unloading effect to computecompression index the load of samples was declined withregard to 39970 19980 and 9990 Kilo Pascal In this testthe test duration for each sample was nine days Moreoverthe logarithmic-time method was used to identify void ratiodistribution with respect to applied pressure Consequentlyboth coefficients as discussed were computed by averagevalue based on different pressure with respect to loadingstages
In terms of permeability assessment sample 5 showsthe maximum permeability regarding use of 10TDA (see
Shock and Vibration 3
1006819
56833941
2729129533382
0102030405060708090
100
001 01 1 10 100
Fine
r (
)
Particle size (mm)
Laterite
(a)
Fine
r (
)
10097969388
6531
32661633
8172050102030405060708090
100
001 01 1 10 100Particle size (mm)
TDA
(b)Fi
ner (
)
10099328881
5966
37292204
1187340
102030405060708090
100
001 01 1 10 100
Particle size (mm)
MS
(c)
Figure 1 Distribution of gradation for different materials (a) Laterite (b) tire driven aggregate and (c) microsilica
00225 30626
006 16767
0065 10698
0045 2327400325 26357
000
5000
10000
15000
20000
25000
30000
35000
0 001 002 003 004 005 006 007 008
Sample 1Sample 4Sample 5
Sample 3Sample 2
Strain
Und
rain
ed sh
ear s
treng
th
Figure 2 Undrained shear strength in the triaxial compressionwithout measurement of pore pressure sample 1 to sample 5
0
2000
4000
6000
8000
10000
12000
14000
16000
Sample 1 Sample 2 Sample 3 Sample 4 Sample 5
1528372
982937
733618
25826214959El
astic
ity m
odul
us (k
Pa)
Figure 3 Distribution of elasticity modulus in samples one to five
1528372
982937733618
25826214959
693668871086
971862850591
55811653648
436286265589
02000400060008000
1000012000140001600018000
Sam
ple 1
Sam
ple 2
Sam
ple 3
Sam
ple 4
Sam
ple 5
Sam
ple 6
Sam
ple 7
Sam
ple 8
Sam
ple 9
Sam
ple 1
0
Sam
ple 1
1
Sam
ple 1
2
Sam
ple 1
3
Elas
ticity
mod
ulus
(kPa
)
Figure 4 Distribution of elasticity modulus in samples
Figure 8) However one of the major factors to design damis seepage controlling Therefore the permeability index wassignificantly improved by using more percentage of silicain this study In Figure 8 the minimum permeability wasobserved in sample 10 (167119864 minus 5 cms)
In terms of shear strength assessment using direct sheartest (small shear box apparatus) sample 10 indicated the bestperformance in order to increase both factors of cohesionand internal angle of friction Table 3 shows distribution ofcohesion and internal angle of friction in different samples
In order to estimate the damping ratio the nonlinearstress-strain characteristics of soils (Figure 9(a)) for anal-ysis purposes can be represented by bilinear relationships(Figure 9(b)) or multilinear relationships However the useof an equivalent linear viscoelastic analysis leads to similarresults Damping ratio depends on both areas as can be seen
4 Shock and Vibration
12000
10000
8000
6000
4000
2000
0
Sample 2 Sample 6 Sample 7
982937
693668
871086
(a)
12000
10000
8000
6000
4000
2000
0
Sample 3 Sample 8 Sample 9
733618
971862850591
(b)
Sample 4 Sample 10 Sample 11
7000
6000
5000
4000
3000
2000
1000
0
258262
55811
653648
(c)
Sample 5 Sample 12 Sample 13
5000
4000
3000
2000
1000
0
14959
436286
265589
(d)
Figure 5 Distribution of elasticity modulus (Kilo Pascal) for samples
377506
642489
327
593688 747
371 421514
333
61
012345678
Sam
ple 1
Sam
ple 2
Sam
ple 3
Sam
ple 4
Sam
ple 5
Sam
ple 6
Sam
ple 7
Sam
ple 8
Sam
ple 9
Sam
ple 1
0
Sam
ple 1
1
Sam
ple 1
2
Sam
ple 1
3
Figure 6 Distribution of area under the curve of stress-strain basedon unconfined test
with blue and red colors in this figure [24] This ratio can begiven as follows
Damping ratio = 119863 = (1
4120587)
lowast (Loop area
area under stress strain curve)
(1)
However the area under stress strain curve and hysteresisloop area can be computed according to Figure 9 Figure 10shows damping ratio for sample 1 and sample 10 respectivelyIt can be seen that this ratio was 1795 in laterite soil Interms of soil improvement the damping coefficient increasedto 2263 for sample 10 (7 TDA with 3 silica)
After discussing all tests in soil mechanic that werecarried out sample 10 shows the excellent performance inorder to reinforce dam Therefore IDL material was defined
Table 3 Distribution of cohesion and angle of internal friction indifferent samples
Sample Cohesion (KPa) Friction (degree)1 2518 30002 1317 35013 2234 31074 1305 36335 301 29396 1474 3367 1682 33588 1815 33479 1557 363110 2638 321011 3494 285712 2711 286713 1486 3252
by using sample 10 In the physical small dam modeling thismaterial to reinforce dam in different location was used
For small scale modeling the river sand was used forfoundation Table 4 presents sand properties It is importantto note that river sand included uniform size particlesbecause uniformity coefficient was less than five In additioncoefficient of curvature was less than oneThe soil is said to bewell graded if this value lies between one and threeThereforethis type of sand was selected in order to critically conditionfoundation
Shock and Vibration 5
01055
0093301137
0117701566
0207
0111201163
00675
01533 01544
00625
0081
0
005
01
015
02
025
Sam
ple 1
Sam
ple 2
Sam
ple 3
Sam
ple 4
Sam
ple 5
Sam
ple 6
Sam
ple 7
Sam
ple 8
Sam
ple 9
Sam
ple 1
0
Sam
ple 1
1
Sam
ple 1
2
Sam
ple 1
3
mv (average)
(m2M
N)
(a) Coefficient of volume compressibility
Sam
ple 1
Sam
ple 2
Sam
ple 3
Sam
ple 4
Sam
ple 5
Sam
ple 6
Sam
ple 7
Sam
ple 8
Sam
ple 9
Sam
ple 1
0
Sam
ple 1
1
Sam
ple 1
2
Sam
ple 1
3
4416
3395
36076
31893463
8159
3118
28552487
11922659
1596
2311
0102030405060708090
cv (average)
(m2y
ear)
(b) Coefficient of consolidation
Figure 7 Distribution of coefficients in samples for consolidation test (a) Coefficient of volume compressibility and (b) coefficient ofconsolidation
Sam
ple 1
Sam
ple 2
Sam
ple 3
Sam
ple 4
Sam
ple 5
Sam
ple 6
Sam
ple 7
Sam
ple 8
Sam
ple 9
Sam
ple 1
0
Sam
ple 1
1
Sam
ple 1
2
Sam
ple 1
3Permeability (cms)
000E + 00
500E minus 05
100E minus 04
150E minus 04
200E minus 04
250E minus 04
300E minus 04
129E minus 05345E minus 05
613E minus 05
710E minus 05
242E minus 04
386E minus 05
450E minus 05
257E minus 05
322E minus 05
167E minus 05
206E minus 05
234E minus 04
213E minus 04
Figure 8 Distribution of permeability for different samples
Table 4 Sand properties
Physical properties ValueSpecific gravity 2547Cohesion (KPa) 000Angle of internal friction (Degree) 35Modulus elasticity (KPa) 32460Maximum dry density (grcm3) 172Minimum dry density (grcm3) 136Density for 119868
119889
= 75 (grcm3) 1613Permeability (cms) 01Maximum size (mm) 200Minimum size (mm) 0075Uniformity coefficient 119862
119906
4375Coefficient of curvature 119862
119888
097
3 Small Scale Model on Vibrator Table
Physical models with scale parameter equal to 1100 weretested In order to research methodology for this purposesome aspects included characteristic of vibrator table dis-placement transducer data logger sinusoidal motion scaleparameter for static or dynamic condition free vibrationanalysis and physical modeling will be presented In this
study five small scale dams were tested as will be explainedin the next section
31 Vibrator Table In this study vibrating table 24-9112(CN-166) with respect to sinus motion was used Figure 11shows the vibrating desk that was cushioned with steeland seminoiseless electromagnetic vibrator with 3600 vpmoperating frequency In addition it has a separate controllerto vary vibrator amplitude in case of frequency capacitylimit 100Hz Table capacity was equal to 750 lbs (340 kg)Double amplitude range was located at 0002 inch (005mm)to 0015 inch (038mm) Actuator was an electromagneticvibrator over 100 lbs (4530 kg)The table was square in shapeand 30 inch (762mm) The table thickness was 333mm ofsteel In case of weight it was net 555 lbs (252 kg) and shippingwas 605 lbs (274 kg) Figure 11 illustrates the vibrator table forthis study
32 Displacement Transducerand Data Logger Displacementtransducer CDP-D was utilized with respect to dual isolatedIO ports By using transducer one set of cables for input andoutput was connected to the analog measuring instrumentand another set to the digital measuring instrument Withtwo different types of measuring equipment connected tothis transducer simultaneous measurements can be madewithout interference Figure 12(a) shows the displacementtransducer and Figure 12(b) shows the dimensions for trans-ducer CDP-100 Tomeasure displacement at both edges of thecrest in small scale modeling two transducers were installedIn terms of data record data logger or data recorder is anelectronic device that records data over time or in relation tolocation with either a built in instrument or a sensor or viaexternal instruments and sensors
Figure 12(c) illustrates the data logger that was used inthis study Based on device ability results were printed duringthe vibration duration After that results were classified byusing Excel program It should be noted that both transducersas mentioned previously were connected to this data logger(UCAM-70A) in order to record vertical displacement duringthe vibration In addition the sub step of vibration periodwas
6 Shock and Vibration
Stress
Strain
(a)
Stress
Strain
(b)
Figure 9 Damping definition and hysteretic and equivalent bilinear stress-strain relationships for soil (a) stress-strain curves (b) bilinearidealization [23]
400
300
200
100
0
minus100
minus200
minus300
minus400
minus003 minus002 minus001 0 001 002 003
0020
00168
00225Stress (kPa)
Strain
Blue area = 377
Loop area = 850
Damping = 01795
Hysteresis loop-sample 1
(a)
250200150100500
minus50minus100minus150minus200minus250
minus006 minus004 minus002 0 002 004 006
00425
0034
00404
Stress (kPa)
Strain
Hysteresis loop-sample 10
Blue area = 421Loop area = 1197
Damping = 02263
(b)
Figure 10 Estimation of damping ratio (a) sample 1 and (b) sample 10
Figure 11 Vibrator table
equal to two seconds based on device ability with respect toprint
33 Sinusoidal Vibrate Loading There is a mathematicalrelationship between frequency displacement velocity andacceleration for sinusoidalmotion according to considerationof the peak value for them The relationship is such that ifany two of the four variables are known the other two can becalculated Table 5 shows all equations that were provided inthis context [25]
Table 5 Conversion for peak value in sinusoidal motion displace-ment (X) velocity (V) acceleration (A) and frequency (f )
Displacement X Velocity V Acceleration A
Displacement X 119883 = 119883 119883 =119881
2120587119891119883 =
119860
(2120587119891)2
Velocity V 119881 = 2120587119891119883 119881 = 119881 119881 =119860
2120587119891
Acceleration A 119860 = (2120587119891)2
119883 119860 = 2120587119891119881 119860 = 119860
119866 in these formulas is not gravity acceleration It is aconstant for calculation within different systems Respec-tively for metric imperial and Si 119866 is 980665ms23860885827 ins2 and 100ms2
Since themotion is sinusoidal the displacement velocityand acceleration are changing sinusoidal trend Howeverthey are not in the same phase The phase relationshipbetween displacement velocity and acceleration is that veloc-ity is 90∘ out of phase with acceleration and displacement is180∘ out of phase with acceleration
Shock and Vibration 7
(a)
CDP-D
12060110120601D
10
120601E
C A
120601BInputoutput 1Inputoutput 2
2 inputoutput cables
Dimensions
TypeCDP-50-D
A B C D E
165 335 65 5 10
(b)
(c)
Figure 12 Transducer and data logger (a) Displacement transducer CDP-100 (b) dimension of displacement transducer (CDP-100) and (c)data logger UCAM-70A
155
minus5minus15
20100
minus10minus20
25155
minus5minus15minus25
Displacement 13mm peak
Velocity 16336ms peak
Acceleration 2090gn peak
Figure 13 20Hz sinusoidal motion
In other words when displacement is at a maximumvelocity is at a minimum and acceleration is at a maximumIt should be noted that 1 119892
119899
= 980665ms2 = 32174 fts2 =3860886 ins2 Figure 13 shows the example of displacementdistribution with velocity and acceleration while the fre-quency of sinusoidal motion is twenty hertz
34 Scaling Laws In case of the scale parameter the scalefactor can be used according to
119909lowast
=119909119898
119909119901
(2)
The subscript 119898 represents ldquomodelrdquo and the subscript 119901represents ldquoprototyperdquo and 119909lowast represents the scale factor forthe quantity 119909 [26]
k
mx
Figure 14 Mass spring system
Figure 15 Free mesh
The reason for spinning a model on a centrifuge is toenable small scale models to feel the same effective stresses asa full scale prototype This goal can be stated mathematicallyas
1205901015840119909
=1205901015840
119898
1205901015840
119901
= 1 (3)
where the asterisk represents the scaling factor for thequantity 1205901015840
119898
is the effective stress in the model and 1205901015840119901
is theeffective stress in the prototype
8 Shock and Vibration
Nodal solutionStep = 1
UX (Avg)RSYS = 0
DMX = 0288E minus 03
SMX = 0271E minus 04
Sub = 1X
Y
Z
MN
MX
minus0271E
minus04
minus0210E
minus04
minus0150E
minus04
minus0902Eminus05
minus0301Eminus05
0301Eminus05
0902Eminus05
0150E
minus04
0210E
minus04
0271E
minus04
SMN = minus0271E minus 04
Freq = 0229855
(a)
Nodal solutionStep = 1
Sub = 1
UY (Avg)RSYS = 0
DMX = 0288E minus 03
SMX = 0126E minus 03
X
Y
Z
MN
MX
minus0971E
minus04
minus0125E
minus03
minus0692E
minus04
minus0413Eminus04
minus0134Eminus04
0145Eminus04
0423E
minus04
0702E
minus04
0981E
minus04
0126E
minus03
SMN = minus0125E minus 03
Freq = 0229855
(b)
X
Y
Z MN
MX
0
0287E
minus04
0575E
minus04
0862Eminus04
0115Eminus03
0144Eminus03
0172Eminus03
0201E
minus03
0230E
minus03
0259E
minus03
Nodal solutionStep = 1
UZ (Avg)RSYS = 0
DMX = 0288E minus 03
SMX = 0259E minus 03
Sub = 1
Freq = 0229855
(c)
X
Y
Z
MX0
0320E
minus04
0639E
minus04
0959Eminus04
0128Eminus03
0160Eminus03
0192Eminus03
0224E
minus03
0256E
minus03
0288E
minus03
Nodal solutionStep = 1
Sub = 1
USUM (Avg)RSYS = 0
DMX = 0288E minus 03
SMX = 0288E minus 03
MN
Freq = 0229855
(d)
Figure 16 Mode shape 1 (a) horizontal displacement (b) vertical displacement (c) lateral displacement and (d) total displacement
In soil mechanics the vertical effective stress 1205901015840 forexample is typically calculated by
1205901015840
= 120590119905
minus 119906 (4)
where 120590119905 and 119906 are total stress and pore pressure respectivelyFor a uniform layer with no pore pressure the total verticalstress at a depth119867may be calculated by
120590119905
= 120588119892119867 (5)
where 120588 represents the density of the layer and 119892 representsgravity In the conventional form of centrifugemodeling [26]it is typical that the same materials are used in the model andprototype therefore the densities are the same in model andprototype that is
120588lowast
= 1 (6)
Furthermore in conventional centrifugemodeling all lengthsare scaled by the same factor 119871lowast To produce the same stressin the model as in the prototype we thus require
120588lowast
119892lowast
119867lowast
= 1119892lowast
119871lowast
= 1 (7)
It may be rewritten as
119892lowast
=1
119871lowast
(8)
The above scaling law states that if lengths in the model arereduced by some factor 119899 then gravitational accelerationsmust be increased by the same factor 119899 in order to preserveequal stresses in model and prototype
Shock and Vibration 9
1650
950
500 5200 500
1000
1000785
Laterite
Water
Sand
(a)
1650
950
500 5200 500
1000
1000785
Laterite
Water
Sand
(b)
1650
950
500 5200 500
1000
1000785
Laterite
Water
Sand
(c)
1650
950
500 5200 500
1000
1000785 Water
Sand
Laterite reinforced
(d)
1650
950
1000
1000785
Laterite
Water
Sand
500 5200 500
(e)
Figure 17 Model introducing ((a) (b) (c) (d) and (e)) for small dam (cm) (119878 = 1100)
For dynamic problems where gravity and accelerationsare important all accelerations must scale as gravity is scaledthat is
119886lowast
= 119892lowast
=1
119871lowast
(9)
Since acceleration has units of 1198711198792 it is required that
119886lowast
=119871lowast
1198792
(10)
Hence it is required that
1
119871lowast
=119871lowast
1198792
or 119879lowast
= 119871lowast
(11)
Frequency has units of inverse of time and velocity has unitsof length per time so for dynamic problems we also obtain
119891lowast
=1
119871lowast
Vlowast =119871lowast
119879lowast
= 1 (12)
For model tests involving dynamics the conflict in time scalefactors may be resolved by scaling the permeability of the soil[26]
35 Free Vibration Analysis In dynamic assessment freevibration analysis is the base of study In fact the distributionof frequency in the different vibrationmode can be computedby the application of modal analysis based on finite-elementmethod (FEM) It is worth mentioning that this analysis isperfectly related to the mass and spring In case of the mass-spring-damper system the first assumption is negligibleabout damping effect Therefore there is not any externalforce on mass in this state The force applied to the massby the spring is proportional to the amount of the springthat is stretched ldquo119909rdquo (it can be assumed that spring isalready compressed due to the weight of the mass) Theproportionality constant (119896) is spring stiffness (see Figure 14)The unit measurement is force divided by distance (kgm)
10 Shock and Vibration
(a) (b)
(c) (d)
Figure 18 Small scale dam (a) Dam perspective with two LVDT (b) soil compaction with roller (c) dam section with index network and(d) dam with tank before vibration
The negative sign indicates that force is always opposingthe motion of the mass attached to it according to thefollowing equation
119865119904
= minus119896119909 (13)
The force generated by the mass is proportional to theacceleration of the mass as given by Newtonrsquos second law ofmotion
sum119865 = 119898119886 = 119898 = 1198981198892
119909
1198891199052
(14)
The sumof the forces on themass then generates this ordinarydifferential equation
119898 + 119896119909 = 0 (15)
Assuming that the initial vibration can be started by stretch-ing and releasing the spring with distance (119860) the solution tothe above equation that describes the motion of mass can beseen in the following equation
119909 (119905) = 119860 cos (2120587119891119899
119905) (16)
This solution shows that it will oscillate with simple harmonicmotion that has amplitude of (119860) and a frequency (119891
119899
) Thenumber (119891
119899
) is called the undamped natural frequency Forthe simple mass-spring system frequency is given by
119891119899
=1
2120587
radic119896
119898 (17)
However the relation between frequency and vibrationperiod is always reverse Consider
119879 =1
119891 (18)
In terms of the measurement unit the vibration periodand frequency were according to seconds and hertz It isworth noting that the dominant frequency is the minimumfrequency to produce maximum vibration period
4 Numerical Analysis
In terms of numerical analysismodal analysis was carried outby using ANSYS program in this study to compute dominantfrequency for small scale model regarding 3D analysis Thisprogram is one of the famous software programs with respectto finite-elementmethod (FEM) In particular this software isone of the universal programs with high level of the ability fordifferent analyses A strong ability to compute free vibrationanalysis is possible with modal analysis [27]
41 Elements and Meshing Process To select element basedon Help menu solid 8 nodes 183 (3D) were used for thispurpose Figure 15 shows the mapped mesh for numericalmodeling In this figure 23956 elements and 35457 nodes inmodels were used for free vibration analysis According tothis condition free vibration analysis to access frequency indifferent vibration modes was carried out as results can bediscussed in the next section
Shock and Vibration 11
0 20 40 60 80 100 1200
minus01
minus02
minus03
minus04
minus05
minus06
62 minus029
90 minus048
Time (s)
Disp
lace
men
t (m
m)
Time (s)0 10 20 30 40 50 60 70 80 90 100 110 120
03
025
02
015
01
005
0
Rela
tive
disp
lace
men
t (m
m)
96 024
Model A
0 20 40 60 80 100 120
Time (s)
Disp
lace
men
t (m
m) 2
15
1
05
0
minus05
minus1
minus15
84 15
104 minus064
Time (s)0 10 20 30 40 50 60 70 80 90 100 110 120
Rela
tive
disp
lace
men
t (m
m) 25
2
15
1
05
0
minus05
minus1
104 213
Model B
0 20 40 60 80 100 120
Time (s)
Disp
lace
men
t (m
m)
01201008006004002
0minus002minus004
108 01
108 006
Time (s)
0 10 20 30 40 50 60 70 80 90 100 110 120
Rela
tive
disp
lace
men
t (m
m)
007
006
005
004
003
002
001
0
8 006
Model C
Time (s)0 10 20 30 40 50 60 70 80 90 100 110 120
Rela
tive
disp
lace
men
t (m
m)
0201501005
0minus005minus01minus015minus02
90 017
26 minus017
0 20 40 60 80 100 120
Time (s)
Disp
lace
men
t (m
m) 015
01005
0
minus01minus015
minus005
minus02minus025
114 minus007116 minus022
Model DTime (s)
Disp
lace
men
t (m
m)
01
0
minus01
minus02
minus03
minus04
104 minus011
102 minus033
0 20 40 60 80 100 120
Up streamDown stream
Time (s)
0 10 20 30 40 50 60 70 80 90 100 110 120
Rela
tive
disp
lace
men
t (m
m)
03
025
02
015
01
0
005
86 025
Model E
Figure 19 Vertical displacement in both edges of the crest in models with relative displacement
12 Shock and Vibration
(a) (b) (c)
Figure 20 Damage in the first model (Model A)
(a) (b)
(c) (d)
Figure 21 Damage in the second model (Model B)
42 Free Vibration Analysis and Dominant Frequency Interms of modal analysis the free vibration analysis was cal-culated by ANSYS program Figure 16 shows displacement inthree directions of model and total displacement in the firstvibration mode because based on distribution of frequencyin the first mode to fifth mode it is important to note thatthe minimum frequency (022986Hz) was observed in thefirst vibration mode It means that the vibration period wasmaximum and critical in this mode
Distribution of frequency in different vibration modesindicated that this value was respectively obtained at026257Hz 028387Hz and 030135Hz in the vibration shapemodes 2 to 4
5 Results and Discussion Based on PhysicalSmall Scale Modeling
In order to find the best location of reinforcement in damfive small dams with different locations of reinforcementusing IDL material were vibrated by dominant frequency
(22986Hz) with respect to resonance condition Figure 17shows five small scale dams (Models (a) (b) (c) and (d))it is obvious that models have the same dimension In thisfigure the reinforced area was illustrated with a hatch areaFor example Model (d) indicated that all dam body wasreinforced For this purpose one steel box for modeling wasused This box made by five sheets of Plexiglas with 20mmthickness One of them was in the base of model The levelof reservoir was 75 of the dam height The scale parameterwas 1100 Itmeans thatmodel was one hundred times smallerthan prototypeThedamheightwas 227meter in reality but itwas made 227 cm in physical model In addition small scalemodeling was coupled by foundation Foundation materialwas dense sand with 75 relative density Sand propertieswere mentioned in soil mechanic test Figure 18 shows somedetails including dam perspective soil compaction networkindex and reservoir In this Figure two LVDT on the middleof model at the both edges of the crest were installed Inorder to achieve support one steel frame and one steel beamwere applied (see Figure 18(a)) However both LVDT wereconnected to data logger device by specific cables In terms
Shock and Vibration 13
(a) (b)
Figure 22 Damage in the third model (Model C)
of compaction soil for each layer the steel roller used wasselected by trial error methodWoodmolding with respect tocontrol slope via network index was used In order to avoidabsorption of soil water content both the described moldswere just soaked by water before use For tank purpose smallscale models were filled up by water with very slow rate
After vibration equal to two minutes for all modelsthe vertical displacement for both slopes such as upstreamand downstream were printed With respect to use of Excelprogram Figure 19 shows the distribution of vertical displace-ment in both edges in the middle of the crest and relativedisplacement in all models It was obvious that distributionof the vertical displacement indicated a same trend for bothmodels such as A and E In both models displacement valueswere negative during the vibration It means that both ofthem were in uplift condition In this figure also maximumandminimum peak of the relative displacement respectivelyoccurred in Models B and C with 213mm and 006mm It isalso worth noting that this value was at convergence positionfor Models A and E with 024mm and 025mm respectively
In terms of damage location in models Figure 20 showsthe damage in Model A which occurred at upstream anddownstream The level of damage was greater in upstream Itwas very sensible occurrence in case of hydrodynamic pres-sure along the vibration Also in this figure the maximumlongitudes cracks (see line C) were observed near to themiddle of dam at the crest For damage at downstream thetransverse cracks significantly occurred in dam toe
Figure 21 shows Model B that was damaged after vibra-tion It can be observed that dam was significantly damagedin some locations such as crest and surfaces Body cracks andfailure process dramatically occurred in both areas near toabutments Also in this figure one transverse crack in themiddle of the crest was seen (see Figure 20(c)) This damagewas significantly repeated at upstream in Model C but itwas placed in dam toe and it can be seen in Figure 22 Inaddition Model D was damaged in three places such as bothabutments and the middle of the upstream Figure 23 showsModel D that was damaged in toe Briefly all four modelswere damaged as discussed previously On the other handa successful way in order to remove damage was obtained inModel E as shown in Figure 24 Figure 24 shows that model
Figure 23 Damage in the fourth model (Model D)
was safe after vibration without any damage In this figurethe reinforced blanket layer using IDLmaterial was indicatedby red circles between dam and foundation In addition itwas very important to note that both surfaces were safe anddam was stable under severe seismic loading like resonancemotion In fact a good absorption of energy with respectto increase of damping was found by using IDL In case ofusing this technique displacement in both edges of the crestwith negative value indicated the uplift situation Moreoverrelative displacement was like the first model Thereforedam behavior before and after reinforcement was similar forboth distributions of displacement Nevertheless Model Ewas successful to remove damage with respect to high levelof damping in blanket layer In fact this model shows theexcellent performance in earth dams when the blanket layerwas expanded below tank
Finally blanket layer using isolator damper layer (IDL)below dam and tank is a good recommendation for earthdams in seismic zonewhen reinforced thickness is one-fourthof damheight As recommended optimization of thickness inthis method is the next study
6 Conclusion
In this study the earth dam performance under severeseismic motion such as resonance was evaluated by usingblanket layer (IDL) With respect to soil mechanic testthe optimum mixture for IDL was designed IDL powderwas made by using some materials Main material was alocal soil (laterite) with 90 and additives such as TDA
14 Shock and Vibration
(a) (b)
(c) (d)
Figure 24 Dam stabilization in the fifth model (Model E)
(tire derived aggregate with 7) and MS (microsilica) with3 were used This material was utilized to reinforce damin small scale physical modeling According to numericalanalysis the dominant frequency (02298Hz) in order tohave maximum effect for modeling vibration was computedBy using this frequency for physical modeling the damagelocation and distribution of vertical displacement at bothedges of the crest in the middle of small dams for five smallmodel with scale 1100 were discussed As results the bestperformance in order to remove damages was obviouslyobserved in Model E while other models were dramaticallydamaged in some locations such as upstream downstreamand crest In addition the thickness of blanket layer in thismodel was one-fourth of dam height Finally this model is anovel method to reinforce dam under strong earthquake likeresonance phenomena recommended for earth dam designin seismic zone
Conflict of Interests
The authors declare that there is no conflict of interestsregarding the publication of this paper
Acknowledgment
This study ismade possible by the support of the InternationalDoctorate Fellowship of Universiti Teknologi Malaysia andit is very much appreciated
References
[1] M Zeghal and A M Abdel-Ghaffar ldquoAnalysis of behavior ofearth dam using strong-motion earthquakes recordsrdquo Journalof Geotechnical Engineering vol 118 no 2 pp 266ndash277 1992
[2] V Gikas andM Sakellariou ldquoSettlement analysis of theMornosearth dam (Greece) evidence from numerical modeling andgeodetic monitoringrdquo Engineering Structures vol 30 no 11 pp3074ndash3081 2008
[3] R Verdugo N Sitar J D Frost et al ldquoSeismic performanceof earth structures during the February 2010 Maule Chileearthquake dams levees tailings dams and retaining wallsrdquoEarthquake Spectra vol 28 no 1 pp S75ndashS96 2012
[4] Y Parish and F N Abadi ldquoDynamic behaviour of earth damsfor variation of earth material stiffnessrdquo Proceedings of WorldAcademy of Science Engineering and Technology vol 50 pp606ndash611 2009
[5] T G Berhe X T Wang and W Wu ldquoNumerical investigationinto the arrangement of clay core on the seismic performanceof earth damsrdquo in Proceedings of the GeoShanghai InternationalConference on Soil Dynamics and Earthquake Engineering pp131ndash138 ASCE June 2010
[6] Z F Xia G L Ye J HWang B Ye and F Zhang ldquoFully couplednumerical analysis of repeated shake-consolidation process ofearth embankment on liquefiable foundationrdquo Soil Dynamicsand Earthquake Engineering vol 30 no 11 pp 1309ndash1318 2010
[7] X J Kong Y Zhou B Xu and D G Zou ldquoAnalysis on seismicfailure mechanism of Zipingpu dam and several reflections ofaseismic design for high rock-fill damrdquo in Proceedings of theEarth and Space pp 3177ndash3189 March 2010
Shock and Vibration 15
[8] A BayraktarM E Kartal and S Adanur ldquoThe effect of concreteslabrockfill interface behavior on the earthquake performanceof a CFR damrdquo International Journal of Non-Linear Mechanicsvol 46 no 1 pp 35ndash46 2011
[9] R P Piao A H Rippe B Myers and K W Lane ldquoEarthdam liquefaction and deformation analysis using numericalmodelingrdquo in Proceedings of the GeoCongress pp 1ndash6 March2006
[10] A W Elgamal ldquoThree-dimensional seismic analysis of la villitadamrdquo Journal of Geotechnical Engineering vol 118 no 12 pp1937ndash1958 1992
[11] B Gordan and B A Azlan ldquoEffect of material properties inCFRD tailing-embankment bridge during a strong earthquakerdquoCaspian Journal of Applied Sciences Research vol 2 no 11 pp61ndash72 2013
[12] A Papalou and J Bielak ldquoSeismic elastic response of Earthdams with canyon interactionrdquo Journal of Geotechnical andGeoenvironmental Engineering vol 127 no 5 pp 446ndash453 2001
[13] Y Yu L Xie and B Zhang ldquoStability of earth-rockfill damsinfluence of geometry on the three-dimensional effectrdquo Com-puters and Geotechnics vol 32 no 5 pp 326ndash339 2005
[14] L H Mejia and H B Seed ldquoComparison of 2-D and 3-D dynamic analyses of earth damsrdquo Journal of GeotechnicalEngineering vol 109 no 11 pp 1383ndash1398 1983
[15] J L Borges ldquoThree-dimensional analysis of embankmentson soft soils incorporating vertical drains by finite elementmethodrdquoComputers andGeotechnics vol 31 no 8 pp 665ndash6762004
[16] A Yildiz ldquoNumerical analyses of embankments on PVDimproved soft claysrdquo Advances in Engineering Software vol 40no 10 pp 1047ndash1055 2009
[17] B Le Hello and P Villard ldquoEmbankments reinforced by pilesand geosynthetics-Numerical and experimental studies dealingwith the transfer of load on the soil embankmentrdquo EngineeringGeology vol 106 no 1-2 pp 78ndash91 2009
[18] S W Abusharar J J Zheng B G Chen and J H Yin ldquoA sim-plified method for analysis of a piled embankment reinforcedwith geosyntheticsrdquo Geotextiles and Geomembranes vol 27 no1 pp 39ndash52 2009
[19] R Noorzad and M Omidvar ldquoSeismic displacement analysisof embankment dams with reinforced cohesive shellrdquo SoilDynamics and Earthquake Engineering vol 30 no 11 pp 1149ndash1157 2010
[20] T Matsumaru K Watanabe and J Isono ldquoApplication ofcement-mixed gravel reinforced by ground for soft groundimprovementrdquo in Proceedings of the 4th Asian Regional Confer-ence on Geosynthetics pp 380ndash385 Shanghai China June 2008
[21] Namdar and A A K Pelko ldquoSeismic evaluation of embank-ment shaking table test and finite element methodrdquo ThePacific Journal of Science and Technology vol 11 no 2 2010httpwwwakamaiuniversityusPJST
[22] L Wang G Zhang and J Zhang ldquoCentrifuge model tests ofgeotextile-reinforced soil embankments during an earthquakerdquoGeotextiles and Geomembranes vol 29 no 3 pp 222ndash232 2011
[23] H B Seed R T Wong I M Idriss and K Tokimatsu ldquoModuliand damping factors for dynamic analyses of cohesionless soilsrdquoJournal of Geotechnical Engineering vol 112 no 11 pp 1016ndash1032 1986
[24] B M Das Advanced Soil Mechanics CRC Press New York NYUSA 2013
[25] M J Griffin Handbook of Human Vibration Academic PressNew York NY USA 2012
[26] J Garnier C Gaudin S M Springman P J Culligan DJ Goodings and D Konig ldquoCatalogue of scaling laws andsimilitude questions in geotechnical centrifuge modellingrdquoInternational Journal of Physical Modelling in Geotechnics vol7 no 3 pp 1ndash23 2007
[27] A Fluent 120 Userrsquos Guide User Inputs for PorousMedia 2009
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Shock and Vibration
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2 Shock and Vibration
be vibrated To improve dam performance the optimumthickness will be finally suggested
2 Laboratory Soil Tests
Two types of experimental tests were carried out in thisstudy Firstly soil mechanic tests were performed based onBritish Standard (BS) in order to design isolator dampinglayer (IDL) Secondly some small scale models with respectto finding the best location to reinforce dam were vibrated byusing vibrator table In terms of soil characters the BritishStandard (BS) for soil mechanic tests was used Based onsoil classification the local laterite soil MH was applied Thesummarizing of laterite properties is illustrated in Table 1 asused in this study
The passing percentage for different materials such aslaterite tire derived aggregate (TDA) and microsilica (MS)was shown in Figure 1 The determination of particle sizedistribution was carried out by using BS 1377-2 1990 Thisfigure shows that the amplitude of material size was locatedbetween 0075mm and 200mm Based on specific gravitytest this value forMSwasmore than TDAThese values wererespectively exposed at 242 and 215 Table 2 shows sampleswith respect to different mixtures to design IDL
According to soil laboratory test undrained shearstrength in the triaxial compression without measurement ofpore pressure (quick undrained) indicated that the strain insamples is increased by using more percentage of TDA it canbe observed in Figure 2 Also in this figure elasticitymodulusis reduced (see histograms in Figure 3) Significantly theyield point was dramatically reduced in this trend Withrespect to increasing flexibility by using maximum TDAfailure stress is possible with lower value Figure 3 showsthat the increase of TDA has effectively led to decrease ofelasticity modulus that was obtained with 9021 for sample5 In fact the elasticity modulus was significantly decreasedby using 10 TDA as mentioned previously Moreover themaximum and minimum values of modulus elasticity wererespectively obtained in sample 1 and sample 5 as can be seenin Figure 4 It is worth noting that the regular increase of themodulus was just found in sample 4 by increase ofmicrosilicawith 7 of TDA (see Figure 5 histogram without filling)In terms of flexibility distribution in samples the maximumand minimum value of the area below curve were located insample 8 and sample 5 as shown in Figure 6 In addition thegood convergence for sample 9 and sample 1 was obtainedIt should be noted that the quick undrained results werecomputed by average from three cases After all flexibilityfactor has the important role in order to absorb energy
According to consolidation test themaximum coefficientof volume compressibility was located in sample 6 with 0207while the minimum value was in sample 13 with 0081 (seeFigure 7(a)) It was revealed that the increase of TDA forsamples 1 to 5 caused increasing of rate regardless of sample 2In fact this coefficient was double value for sample 5with 10TDA In addition the minimum value was observed by 10TDA with 4 silica (see sample 12) Also in Figure 7(b) themaximum and minimum coefficient of consolidation were
Table 1 Characteristics of the laterite soil
Physical properties ValueSpecific gravity 240Liquid limit LL () 75Plastic limit PL () 41Plasticity index PI () 34BS classification MHMaximum dry density (g cmminus3) 133Optimum moisture content () 35Unconfined compressive strength (KPa) 30626Cohesion (KPa) 2518Angle of internal friction (degree) 3000Modulus elasticity (KPa) 1528372Coefficient of volume compressibility (mv m2MN) 01055Coefficient of consolidation (cv m2yr) 4416Permeability (cmseconds) 129119864 minus 5
Table 2 Sample definition
Sample number Component1 Laterite2 Laterite + 3 TDA3 Laterite + 5 TDA4 Laterite + 7 TDA5 Laterite + 10 TDA6 Laterite + 3 TDA + 2 silica7 Laterite + 3 TDA + 3 silica8 Laterite + 5 TDA + 2 silica9 Laterite + 5 TDA + 3 silica10 Laterite + 7 TDA + 3 silica11 Laterite + 7 TDA + 4 silica12 Laterite + 10 TDA + 4 silica13 Laterite + 10 TDA + 5 silica
respectively observed in sample 6 and sample 10 This factorwas progressively reduced by more percentage of TDA andsilicaTherefore the impact of silica to decrease consolidationcoefficient was greater than TDA
It should be noted that the determination of the one-dimensional consolidation properties based on BS 1377-51990 was carried out All samples were tested by using loadssuch as 25 50 999 19980 39970 and 7994 Kilo Pascal Inaddition in order to evaluate unloading effect to computecompression index the load of samples was declined withregard to 39970 19980 and 9990 Kilo Pascal In this testthe test duration for each sample was nine days Moreoverthe logarithmic-time method was used to identify void ratiodistribution with respect to applied pressure Consequentlyboth coefficients as discussed were computed by averagevalue based on different pressure with respect to loadingstages
In terms of permeability assessment sample 5 showsthe maximum permeability regarding use of 10TDA (see
Shock and Vibration 3
1006819
56833941
2729129533382
0102030405060708090
100
001 01 1 10 100
Fine
r (
)
Particle size (mm)
Laterite
(a)
Fine
r (
)
10097969388
6531
32661633
8172050102030405060708090
100
001 01 1 10 100Particle size (mm)
TDA
(b)Fi
ner (
)
10099328881
5966
37292204
1187340
102030405060708090
100
001 01 1 10 100
Particle size (mm)
MS
(c)
Figure 1 Distribution of gradation for different materials (a) Laterite (b) tire driven aggregate and (c) microsilica
00225 30626
006 16767
0065 10698
0045 2327400325 26357
000
5000
10000
15000
20000
25000
30000
35000
0 001 002 003 004 005 006 007 008
Sample 1Sample 4Sample 5
Sample 3Sample 2
Strain
Und
rain
ed sh
ear s
treng
th
Figure 2 Undrained shear strength in the triaxial compressionwithout measurement of pore pressure sample 1 to sample 5
0
2000
4000
6000
8000
10000
12000
14000
16000
Sample 1 Sample 2 Sample 3 Sample 4 Sample 5
1528372
982937
733618
25826214959El
astic
ity m
odul
us (k
Pa)
Figure 3 Distribution of elasticity modulus in samples one to five
1528372
982937733618
25826214959
693668871086
971862850591
55811653648
436286265589
02000400060008000
1000012000140001600018000
Sam
ple 1
Sam
ple 2
Sam
ple 3
Sam
ple 4
Sam
ple 5
Sam
ple 6
Sam
ple 7
Sam
ple 8
Sam
ple 9
Sam
ple 1
0
Sam
ple 1
1
Sam
ple 1
2
Sam
ple 1
3
Elas
ticity
mod
ulus
(kPa
)
Figure 4 Distribution of elasticity modulus in samples
Figure 8) However one of the major factors to design damis seepage controlling Therefore the permeability index wassignificantly improved by using more percentage of silicain this study In Figure 8 the minimum permeability wasobserved in sample 10 (167119864 minus 5 cms)
In terms of shear strength assessment using direct sheartest (small shear box apparatus) sample 10 indicated the bestperformance in order to increase both factors of cohesionand internal angle of friction Table 3 shows distribution ofcohesion and internal angle of friction in different samples
In order to estimate the damping ratio the nonlinearstress-strain characteristics of soils (Figure 9(a)) for anal-ysis purposes can be represented by bilinear relationships(Figure 9(b)) or multilinear relationships However the useof an equivalent linear viscoelastic analysis leads to similarresults Damping ratio depends on both areas as can be seen
4 Shock and Vibration
12000
10000
8000
6000
4000
2000
0
Sample 2 Sample 6 Sample 7
982937
693668
871086
(a)
12000
10000
8000
6000
4000
2000
0
Sample 3 Sample 8 Sample 9
733618
971862850591
(b)
Sample 4 Sample 10 Sample 11
7000
6000
5000
4000
3000
2000
1000
0
258262
55811
653648
(c)
Sample 5 Sample 12 Sample 13
5000
4000
3000
2000
1000
0
14959
436286
265589
(d)
Figure 5 Distribution of elasticity modulus (Kilo Pascal) for samples
377506
642489
327
593688 747
371 421514
333
61
012345678
Sam
ple 1
Sam
ple 2
Sam
ple 3
Sam
ple 4
Sam
ple 5
Sam
ple 6
Sam
ple 7
Sam
ple 8
Sam
ple 9
Sam
ple 1
0
Sam
ple 1
1
Sam
ple 1
2
Sam
ple 1
3
Figure 6 Distribution of area under the curve of stress-strain basedon unconfined test
with blue and red colors in this figure [24] This ratio can begiven as follows
Damping ratio = 119863 = (1
4120587)
lowast (Loop area
area under stress strain curve)
(1)
However the area under stress strain curve and hysteresisloop area can be computed according to Figure 9 Figure 10shows damping ratio for sample 1 and sample 10 respectivelyIt can be seen that this ratio was 1795 in laterite soil Interms of soil improvement the damping coefficient increasedto 2263 for sample 10 (7 TDA with 3 silica)
After discussing all tests in soil mechanic that werecarried out sample 10 shows the excellent performance inorder to reinforce dam Therefore IDL material was defined
Table 3 Distribution of cohesion and angle of internal friction indifferent samples
Sample Cohesion (KPa) Friction (degree)1 2518 30002 1317 35013 2234 31074 1305 36335 301 29396 1474 3367 1682 33588 1815 33479 1557 363110 2638 321011 3494 285712 2711 286713 1486 3252
by using sample 10 In the physical small dam modeling thismaterial to reinforce dam in different location was used
For small scale modeling the river sand was used forfoundation Table 4 presents sand properties It is importantto note that river sand included uniform size particlesbecause uniformity coefficient was less than five In additioncoefficient of curvature was less than oneThe soil is said to bewell graded if this value lies between one and threeThereforethis type of sand was selected in order to critically conditionfoundation
Shock and Vibration 5
01055
0093301137
0117701566
0207
0111201163
00675
01533 01544
00625
0081
0
005
01
015
02
025
Sam
ple 1
Sam
ple 2
Sam
ple 3
Sam
ple 4
Sam
ple 5
Sam
ple 6
Sam
ple 7
Sam
ple 8
Sam
ple 9
Sam
ple 1
0
Sam
ple 1
1
Sam
ple 1
2
Sam
ple 1
3
mv (average)
(m2M
N)
(a) Coefficient of volume compressibility
Sam
ple 1
Sam
ple 2
Sam
ple 3
Sam
ple 4
Sam
ple 5
Sam
ple 6
Sam
ple 7
Sam
ple 8
Sam
ple 9
Sam
ple 1
0
Sam
ple 1
1
Sam
ple 1
2
Sam
ple 1
3
4416
3395
36076
31893463
8159
3118
28552487
11922659
1596
2311
0102030405060708090
cv (average)
(m2y
ear)
(b) Coefficient of consolidation
Figure 7 Distribution of coefficients in samples for consolidation test (a) Coefficient of volume compressibility and (b) coefficient ofconsolidation
Sam
ple 1
Sam
ple 2
Sam
ple 3
Sam
ple 4
Sam
ple 5
Sam
ple 6
Sam
ple 7
Sam
ple 8
Sam
ple 9
Sam
ple 1
0
Sam
ple 1
1
Sam
ple 1
2
Sam
ple 1
3Permeability (cms)
000E + 00
500E minus 05
100E minus 04
150E minus 04
200E minus 04
250E minus 04
300E minus 04
129E minus 05345E minus 05
613E minus 05
710E minus 05
242E minus 04
386E minus 05
450E minus 05
257E minus 05
322E minus 05
167E minus 05
206E minus 05
234E minus 04
213E minus 04
Figure 8 Distribution of permeability for different samples
Table 4 Sand properties
Physical properties ValueSpecific gravity 2547Cohesion (KPa) 000Angle of internal friction (Degree) 35Modulus elasticity (KPa) 32460Maximum dry density (grcm3) 172Minimum dry density (grcm3) 136Density for 119868
119889
= 75 (grcm3) 1613Permeability (cms) 01Maximum size (mm) 200Minimum size (mm) 0075Uniformity coefficient 119862
119906
4375Coefficient of curvature 119862
119888
097
3 Small Scale Model on Vibrator Table
Physical models with scale parameter equal to 1100 weretested In order to research methodology for this purposesome aspects included characteristic of vibrator table dis-placement transducer data logger sinusoidal motion scaleparameter for static or dynamic condition free vibrationanalysis and physical modeling will be presented In this
study five small scale dams were tested as will be explainedin the next section
31 Vibrator Table In this study vibrating table 24-9112(CN-166) with respect to sinus motion was used Figure 11shows the vibrating desk that was cushioned with steeland seminoiseless electromagnetic vibrator with 3600 vpmoperating frequency In addition it has a separate controllerto vary vibrator amplitude in case of frequency capacitylimit 100Hz Table capacity was equal to 750 lbs (340 kg)Double amplitude range was located at 0002 inch (005mm)to 0015 inch (038mm) Actuator was an electromagneticvibrator over 100 lbs (4530 kg)The table was square in shapeand 30 inch (762mm) The table thickness was 333mm ofsteel In case of weight it was net 555 lbs (252 kg) and shippingwas 605 lbs (274 kg) Figure 11 illustrates the vibrator table forthis study
32 Displacement Transducerand Data Logger Displacementtransducer CDP-D was utilized with respect to dual isolatedIO ports By using transducer one set of cables for input andoutput was connected to the analog measuring instrumentand another set to the digital measuring instrument Withtwo different types of measuring equipment connected tothis transducer simultaneous measurements can be madewithout interference Figure 12(a) shows the displacementtransducer and Figure 12(b) shows the dimensions for trans-ducer CDP-100 Tomeasure displacement at both edges of thecrest in small scale modeling two transducers were installedIn terms of data record data logger or data recorder is anelectronic device that records data over time or in relation tolocation with either a built in instrument or a sensor or viaexternal instruments and sensors
Figure 12(c) illustrates the data logger that was used inthis study Based on device ability results were printed duringthe vibration duration After that results were classified byusing Excel program It should be noted that both transducersas mentioned previously were connected to this data logger(UCAM-70A) in order to record vertical displacement duringthe vibration In addition the sub step of vibration periodwas
6 Shock and Vibration
Stress
Strain
(a)
Stress
Strain
(b)
Figure 9 Damping definition and hysteretic and equivalent bilinear stress-strain relationships for soil (a) stress-strain curves (b) bilinearidealization [23]
400
300
200
100
0
minus100
minus200
minus300
minus400
minus003 minus002 minus001 0 001 002 003
0020
00168
00225Stress (kPa)
Strain
Blue area = 377
Loop area = 850
Damping = 01795
Hysteresis loop-sample 1
(a)
250200150100500
minus50minus100minus150minus200minus250
minus006 minus004 minus002 0 002 004 006
00425
0034
00404
Stress (kPa)
Strain
Hysteresis loop-sample 10
Blue area = 421Loop area = 1197
Damping = 02263
(b)
Figure 10 Estimation of damping ratio (a) sample 1 and (b) sample 10
Figure 11 Vibrator table
equal to two seconds based on device ability with respect toprint
33 Sinusoidal Vibrate Loading There is a mathematicalrelationship between frequency displacement velocity andacceleration for sinusoidalmotion according to considerationof the peak value for them The relationship is such that ifany two of the four variables are known the other two can becalculated Table 5 shows all equations that were provided inthis context [25]
Table 5 Conversion for peak value in sinusoidal motion displace-ment (X) velocity (V) acceleration (A) and frequency (f )
Displacement X Velocity V Acceleration A
Displacement X 119883 = 119883 119883 =119881
2120587119891119883 =
119860
(2120587119891)2
Velocity V 119881 = 2120587119891119883 119881 = 119881 119881 =119860
2120587119891
Acceleration A 119860 = (2120587119891)2
119883 119860 = 2120587119891119881 119860 = 119860
119866 in these formulas is not gravity acceleration It is aconstant for calculation within different systems Respec-tively for metric imperial and Si 119866 is 980665ms23860885827 ins2 and 100ms2
Since themotion is sinusoidal the displacement velocityand acceleration are changing sinusoidal trend Howeverthey are not in the same phase The phase relationshipbetween displacement velocity and acceleration is that veloc-ity is 90∘ out of phase with acceleration and displacement is180∘ out of phase with acceleration
Shock and Vibration 7
(a)
CDP-D
12060110120601D
10
120601E
C A
120601BInputoutput 1Inputoutput 2
2 inputoutput cables
Dimensions
TypeCDP-50-D
A B C D E
165 335 65 5 10
(b)
(c)
Figure 12 Transducer and data logger (a) Displacement transducer CDP-100 (b) dimension of displacement transducer (CDP-100) and (c)data logger UCAM-70A
155
minus5minus15
20100
minus10minus20
25155
minus5minus15minus25
Displacement 13mm peak
Velocity 16336ms peak
Acceleration 2090gn peak
Figure 13 20Hz sinusoidal motion
In other words when displacement is at a maximumvelocity is at a minimum and acceleration is at a maximumIt should be noted that 1 119892
119899
= 980665ms2 = 32174 fts2 =3860886 ins2 Figure 13 shows the example of displacementdistribution with velocity and acceleration while the fre-quency of sinusoidal motion is twenty hertz
34 Scaling Laws In case of the scale parameter the scalefactor can be used according to
119909lowast
=119909119898
119909119901
(2)
The subscript 119898 represents ldquomodelrdquo and the subscript 119901represents ldquoprototyperdquo and 119909lowast represents the scale factor forthe quantity 119909 [26]
k
mx
Figure 14 Mass spring system
Figure 15 Free mesh
The reason for spinning a model on a centrifuge is toenable small scale models to feel the same effective stresses asa full scale prototype This goal can be stated mathematicallyas
1205901015840119909
=1205901015840
119898
1205901015840
119901
= 1 (3)
where the asterisk represents the scaling factor for thequantity 1205901015840
119898
is the effective stress in the model and 1205901015840119901
is theeffective stress in the prototype
8 Shock and Vibration
Nodal solutionStep = 1
UX (Avg)RSYS = 0
DMX = 0288E minus 03
SMX = 0271E minus 04
Sub = 1X
Y
Z
MN
MX
minus0271E
minus04
minus0210E
minus04
minus0150E
minus04
minus0902Eminus05
minus0301Eminus05
0301Eminus05
0902Eminus05
0150E
minus04
0210E
minus04
0271E
minus04
SMN = minus0271E minus 04
Freq = 0229855
(a)
Nodal solutionStep = 1
Sub = 1
UY (Avg)RSYS = 0
DMX = 0288E minus 03
SMX = 0126E minus 03
X
Y
Z
MN
MX
minus0971E
minus04
minus0125E
minus03
minus0692E
minus04
minus0413Eminus04
minus0134Eminus04
0145Eminus04
0423E
minus04
0702E
minus04
0981E
minus04
0126E
minus03
SMN = minus0125E minus 03
Freq = 0229855
(b)
X
Y
Z MN
MX
0
0287E
minus04
0575E
minus04
0862Eminus04
0115Eminus03
0144Eminus03
0172Eminus03
0201E
minus03
0230E
minus03
0259E
minus03
Nodal solutionStep = 1
UZ (Avg)RSYS = 0
DMX = 0288E minus 03
SMX = 0259E minus 03
Sub = 1
Freq = 0229855
(c)
X
Y
Z
MX0
0320E
minus04
0639E
minus04
0959Eminus04
0128Eminus03
0160Eminus03
0192Eminus03
0224E
minus03
0256E
minus03
0288E
minus03
Nodal solutionStep = 1
Sub = 1
USUM (Avg)RSYS = 0
DMX = 0288E minus 03
SMX = 0288E minus 03
MN
Freq = 0229855
(d)
Figure 16 Mode shape 1 (a) horizontal displacement (b) vertical displacement (c) lateral displacement and (d) total displacement
In soil mechanics the vertical effective stress 1205901015840 forexample is typically calculated by
1205901015840
= 120590119905
minus 119906 (4)
where 120590119905 and 119906 are total stress and pore pressure respectivelyFor a uniform layer with no pore pressure the total verticalstress at a depth119867may be calculated by
120590119905
= 120588119892119867 (5)
where 120588 represents the density of the layer and 119892 representsgravity In the conventional form of centrifugemodeling [26]it is typical that the same materials are used in the model andprototype therefore the densities are the same in model andprototype that is
120588lowast
= 1 (6)
Furthermore in conventional centrifugemodeling all lengthsare scaled by the same factor 119871lowast To produce the same stressin the model as in the prototype we thus require
120588lowast
119892lowast
119867lowast
= 1119892lowast
119871lowast
= 1 (7)
It may be rewritten as
119892lowast
=1
119871lowast
(8)
The above scaling law states that if lengths in the model arereduced by some factor 119899 then gravitational accelerationsmust be increased by the same factor 119899 in order to preserveequal stresses in model and prototype
Shock and Vibration 9
1650
950
500 5200 500
1000
1000785
Laterite
Water
Sand
(a)
1650
950
500 5200 500
1000
1000785
Laterite
Water
Sand
(b)
1650
950
500 5200 500
1000
1000785
Laterite
Water
Sand
(c)
1650
950
500 5200 500
1000
1000785 Water
Sand
Laterite reinforced
(d)
1650
950
1000
1000785
Laterite
Water
Sand
500 5200 500
(e)
Figure 17 Model introducing ((a) (b) (c) (d) and (e)) for small dam (cm) (119878 = 1100)
For dynamic problems where gravity and accelerationsare important all accelerations must scale as gravity is scaledthat is
119886lowast
= 119892lowast
=1
119871lowast
(9)
Since acceleration has units of 1198711198792 it is required that
119886lowast
=119871lowast
1198792
(10)
Hence it is required that
1
119871lowast
=119871lowast
1198792
or 119879lowast
= 119871lowast
(11)
Frequency has units of inverse of time and velocity has unitsof length per time so for dynamic problems we also obtain
119891lowast
=1
119871lowast
Vlowast =119871lowast
119879lowast
= 1 (12)
For model tests involving dynamics the conflict in time scalefactors may be resolved by scaling the permeability of the soil[26]
35 Free Vibration Analysis In dynamic assessment freevibration analysis is the base of study In fact the distributionof frequency in the different vibrationmode can be computedby the application of modal analysis based on finite-elementmethod (FEM) It is worth mentioning that this analysis isperfectly related to the mass and spring In case of the mass-spring-damper system the first assumption is negligibleabout damping effect Therefore there is not any externalforce on mass in this state The force applied to the massby the spring is proportional to the amount of the springthat is stretched ldquo119909rdquo (it can be assumed that spring isalready compressed due to the weight of the mass) Theproportionality constant (119896) is spring stiffness (see Figure 14)The unit measurement is force divided by distance (kgm)
10 Shock and Vibration
(a) (b)
(c) (d)
Figure 18 Small scale dam (a) Dam perspective with two LVDT (b) soil compaction with roller (c) dam section with index network and(d) dam with tank before vibration
The negative sign indicates that force is always opposingthe motion of the mass attached to it according to thefollowing equation
119865119904
= minus119896119909 (13)
The force generated by the mass is proportional to theacceleration of the mass as given by Newtonrsquos second law ofmotion
sum119865 = 119898119886 = 119898 = 1198981198892
119909
1198891199052
(14)
The sumof the forces on themass then generates this ordinarydifferential equation
119898 + 119896119909 = 0 (15)
Assuming that the initial vibration can be started by stretch-ing and releasing the spring with distance (119860) the solution tothe above equation that describes the motion of mass can beseen in the following equation
119909 (119905) = 119860 cos (2120587119891119899
119905) (16)
This solution shows that it will oscillate with simple harmonicmotion that has amplitude of (119860) and a frequency (119891
119899
) Thenumber (119891
119899
) is called the undamped natural frequency Forthe simple mass-spring system frequency is given by
119891119899
=1
2120587
radic119896
119898 (17)
However the relation between frequency and vibrationperiod is always reverse Consider
119879 =1
119891 (18)
In terms of the measurement unit the vibration periodand frequency were according to seconds and hertz It isworth noting that the dominant frequency is the minimumfrequency to produce maximum vibration period
4 Numerical Analysis
In terms of numerical analysismodal analysis was carried outby using ANSYS program in this study to compute dominantfrequency for small scale model regarding 3D analysis Thisprogram is one of the famous software programs with respectto finite-elementmethod (FEM) In particular this software isone of the universal programs with high level of the ability fordifferent analyses A strong ability to compute free vibrationanalysis is possible with modal analysis [27]
41 Elements and Meshing Process To select element basedon Help menu solid 8 nodes 183 (3D) were used for thispurpose Figure 15 shows the mapped mesh for numericalmodeling In this figure 23956 elements and 35457 nodes inmodels were used for free vibration analysis According tothis condition free vibration analysis to access frequency indifferent vibration modes was carried out as results can bediscussed in the next section
Shock and Vibration 11
0 20 40 60 80 100 1200
minus01
minus02
minus03
minus04
minus05
minus06
62 minus029
90 minus048
Time (s)
Disp
lace
men
t (m
m)
Time (s)0 10 20 30 40 50 60 70 80 90 100 110 120
03
025
02
015
01
005
0
Rela
tive
disp
lace
men
t (m
m)
96 024
Model A
0 20 40 60 80 100 120
Time (s)
Disp
lace
men
t (m
m) 2
15
1
05
0
minus05
minus1
minus15
84 15
104 minus064
Time (s)0 10 20 30 40 50 60 70 80 90 100 110 120
Rela
tive
disp
lace
men
t (m
m) 25
2
15
1
05
0
minus05
minus1
104 213
Model B
0 20 40 60 80 100 120
Time (s)
Disp
lace
men
t (m
m)
01201008006004002
0minus002minus004
108 01
108 006
Time (s)
0 10 20 30 40 50 60 70 80 90 100 110 120
Rela
tive
disp
lace
men
t (m
m)
007
006
005
004
003
002
001
0
8 006
Model C
Time (s)0 10 20 30 40 50 60 70 80 90 100 110 120
Rela
tive
disp
lace
men
t (m
m)
0201501005
0minus005minus01minus015minus02
90 017
26 minus017
0 20 40 60 80 100 120
Time (s)
Disp
lace
men
t (m
m) 015
01005
0
minus01minus015
minus005
minus02minus025
114 minus007116 minus022
Model DTime (s)
Disp
lace
men
t (m
m)
01
0
minus01
minus02
minus03
minus04
104 minus011
102 minus033
0 20 40 60 80 100 120
Up streamDown stream
Time (s)
0 10 20 30 40 50 60 70 80 90 100 110 120
Rela
tive
disp
lace
men
t (m
m)
03
025
02
015
01
0
005
86 025
Model E
Figure 19 Vertical displacement in both edges of the crest in models with relative displacement
12 Shock and Vibration
(a) (b) (c)
Figure 20 Damage in the first model (Model A)
(a) (b)
(c) (d)
Figure 21 Damage in the second model (Model B)
42 Free Vibration Analysis and Dominant Frequency Interms of modal analysis the free vibration analysis was cal-culated by ANSYS program Figure 16 shows displacement inthree directions of model and total displacement in the firstvibration mode because based on distribution of frequencyin the first mode to fifth mode it is important to note thatthe minimum frequency (022986Hz) was observed in thefirst vibration mode It means that the vibration period wasmaximum and critical in this mode
Distribution of frequency in different vibration modesindicated that this value was respectively obtained at026257Hz 028387Hz and 030135Hz in the vibration shapemodes 2 to 4
5 Results and Discussion Based on PhysicalSmall Scale Modeling
In order to find the best location of reinforcement in damfive small dams with different locations of reinforcementusing IDL material were vibrated by dominant frequency
(22986Hz) with respect to resonance condition Figure 17shows five small scale dams (Models (a) (b) (c) and (d))it is obvious that models have the same dimension In thisfigure the reinforced area was illustrated with a hatch areaFor example Model (d) indicated that all dam body wasreinforced For this purpose one steel box for modeling wasused This box made by five sheets of Plexiglas with 20mmthickness One of them was in the base of model The levelof reservoir was 75 of the dam height The scale parameterwas 1100 Itmeans thatmodel was one hundred times smallerthan prototypeThedamheightwas 227meter in reality but itwas made 227 cm in physical model In addition small scalemodeling was coupled by foundation Foundation materialwas dense sand with 75 relative density Sand propertieswere mentioned in soil mechanic test Figure 18 shows somedetails including dam perspective soil compaction networkindex and reservoir In this Figure two LVDT on the middleof model at the both edges of the crest were installed Inorder to achieve support one steel frame and one steel beamwere applied (see Figure 18(a)) However both LVDT wereconnected to data logger device by specific cables In terms
Shock and Vibration 13
(a) (b)
Figure 22 Damage in the third model (Model C)
of compaction soil for each layer the steel roller used wasselected by trial error methodWoodmolding with respect tocontrol slope via network index was used In order to avoidabsorption of soil water content both the described moldswere just soaked by water before use For tank purpose smallscale models were filled up by water with very slow rate
After vibration equal to two minutes for all modelsthe vertical displacement for both slopes such as upstreamand downstream were printed With respect to use of Excelprogram Figure 19 shows the distribution of vertical displace-ment in both edges in the middle of the crest and relativedisplacement in all models It was obvious that distributionof the vertical displacement indicated a same trend for bothmodels such as A and E In both models displacement valueswere negative during the vibration It means that both ofthem were in uplift condition In this figure also maximumandminimum peak of the relative displacement respectivelyoccurred in Models B and C with 213mm and 006mm It isalso worth noting that this value was at convergence positionfor Models A and E with 024mm and 025mm respectively
In terms of damage location in models Figure 20 showsthe damage in Model A which occurred at upstream anddownstream The level of damage was greater in upstream Itwas very sensible occurrence in case of hydrodynamic pres-sure along the vibration Also in this figure the maximumlongitudes cracks (see line C) were observed near to themiddle of dam at the crest For damage at downstream thetransverse cracks significantly occurred in dam toe
Figure 21 shows Model B that was damaged after vibra-tion It can be observed that dam was significantly damagedin some locations such as crest and surfaces Body cracks andfailure process dramatically occurred in both areas near toabutments Also in this figure one transverse crack in themiddle of the crest was seen (see Figure 20(c)) This damagewas significantly repeated at upstream in Model C but itwas placed in dam toe and it can be seen in Figure 22 Inaddition Model D was damaged in three places such as bothabutments and the middle of the upstream Figure 23 showsModel D that was damaged in toe Briefly all four modelswere damaged as discussed previously On the other handa successful way in order to remove damage was obtained inModel E as shown in Figure 24 Figure 24 shows that model
Figure 23 Damage in the fourth model (Model D)
was safe after vibration without any damage In this figurethe reinforced blanket layer using IDLmaterial was indicatedby red circles between dam and foundation In addition itwas very important to note that both surfaces were safe anddam was stable under severe seismic loading like resonancemotion In fact a good absorption of energy with respectto increase of damping was found by using IDL In case ofusing this technique displacement in both edges of the crestwith negative value indicated the uplift situation Moreoverrelative displacement was like the first model Thereforedam behavior before and after reinforcement was similar forboth distributions of displacement Nevertheless Model Ewas successful to remove damage with respect to high levelof damping in blanket layer In fact this model shows theexcellent performance in earth dams when the blanket layerwas expanded below tank
Finally blanket layer using isolator damper layer (IDL)below dam and tank is a good recommendation for earthdams in seismic zonewhen reinforced thickness is one-fourthof damheight As recommended optimization of thickness inthis method is the next study
6 Conclusion
In this study the earth dam performance under severeseismic motion such as resonance was evaluated by usingblanket layer (IDL) With respect to soil mechanic testthe optimum mixture for IDL was designed IDL powderwas made by using some materials Main material was alocal soil (laterite) with 90 and additives such as TDA
14 Shock and Vibration
(a) (b)
(c) (d)
Figure 24 Dam stabilization in the fifth model (Model E)
(tire derived aggregate with 7) and MS (microsilica) with3 were used This material was utilized to reinforce damin small scale physical modeling According to numericalanalysis the dominant frequency (02298Hz) in order tohave maximum effect for modeling vibration was computedBy using this frequency for physical modeling the damagelocation and distribution of vertical displacement at bothedges of the crest in the middle of small dams for five smallmodel with scale 1100 were discussed As results the bestperformance in order to remove damages was obviouslyobserved in Model E while other models were dramaticallydamaged in some locations such as upstream downstreamand crest In addition the thickness of blanket layer in thismodel was one-fourth of dam height Finally this model is anovel method to reinforce dam under strong earthquake likeresonance phenomena recommended for earth dam designin seismic zone
Conflict of Interests
The authors declare that there is no conflict of interestsregarding the publication of this paper
Acknowledgment
This study ismade possible by the support of the InternationalDoctorate Fellowship of Universiti Teknologi Malaysia andit is very much appreciated
References
[1] M Zeghal and A M Abdel-Ghaffar ldquoAnalysis of behavior ofearth dam using strong-motion earthquakes recordsrdquo Journalof Geotechnical Engineering vol 118 no 2 pp 266ndash277 1992
[2] V Gikas andM Sakellariou ldquoSettlement analysis of theMornosearth dam (Greece) evidence from numerical modeling andgeodetic monitoringrdquo Engineering Structures vol 30 no 11 pp3074ndash3081 2008
[3] R Verdugo N Sitar J D Frost et al ldquoSeismic performanceof earth structures during the February 2010 Maule Chileearthquake dams levees tailings dams and retaining wallsrdquoEarthquake Spectra vol 28 no 1 pp S75ndashS96 2012
[4] Y Parish and F N Abadi ldquoDynamic behaviour of earth damsfor variation of earth material stiffnessrdquo Proceedings of WorldAcademy of Science Engineering and Technology vol 50 pp606ndash611 2009
[5] T G Berhe X T Wang and W Wu ldquoNumerical investigationinto the arrangement of clay core on the seismic performanceof earth damsrdquo in Proceedings of the GeoShanghai InternationalConference on Soil Dynamics and Earthquake Engineering pp131ndash138 ASCE June 2010
[6] Z F Xia G L Ye J HWang B Ye and F Zhang ldquoFully couplednumerical analysis of repeated shake-consolidation process ofearth embankment on liquefiable foundationrdquo Soil Dynamicsand Earthquake Engineering vol 30 no 11 pp 1309ndash1318 2010
[7] X J Kong Y Zhou B Xu and D G Zou ldquoAnalysis on seismicfailure mechanism of Zipingpu dam and several reflections ofaseismic design for high rock-fill damrdquo in Proceedings of theEarth and Space pp 3177ndash3189 March 2010
Shock and Vibration 15
[8] A BayraktarM E Kartal and S Adanur ldquoThe effect of concreteslabrockfill interface behavior on the earthquake performanceof a CFR damrdquo International Journal of Non-Linear Mechanicsvol 46 no 1 pp 35ndash46 2011
[9] R P Piao A H Rippe B Myers and K W Lane ldquoEarthdam liquefaction and deformation analysis using numericalmodelingrdquo in Proceedings of the GeoCongress pp 1ndash6 March2006
[10] A W Elgamal ldquoThree-dimensional seismic analysis of la villitadamrdquo Journal of Geotechnical Engineering vol 118 no 12 pp1937ndash1958 1992
[11] B Gordan and B A Azlan ldquoEffect of material properties inCFRD tailing-embankment bridge during a strong earthquakerdquoCaspian Journal of Applied Sciences Research vol 2 no 11 pp61ndash72 2013
[12] A Papalou and J Bielak ldquoSeismic elastic response of Earthdams with canyon interactionrdquo Journal of Geotechnical andGeoenvironmental Engineering vol 127 no 5 pp 446ndash453 2001
[13] Y Yu L Xie and B Zhang ldquoStability of earth-rockfill damsinfluence of geometry on the three-dimensional effectrdquo Com-puters and Geotechnics vol 32 no 5 pp 326ndash339 2005
[14] L H Mejia and H B Seed ldquoComparison of 2-D and 3-D dynamic analyses of earth damsrdquo Journal of GeotechnicalEngineering vol 109 no 11 pp 1383ndash1398 1983
[15] J L Borges ldquoThree-dimensional analysis of embankmentson soft soils incorporating vertical drains by finite elementmethodrdquoComputers andGeotechnics vol 31 no 8 pp 665ndash6762004
[16] A Yildiz ldquoNumerical analyses of embankments on PVDimproved soft claysrdquo Advances in Engineering Software vol 40no 10 pp 1047ndash1055 2009
[17] B Le Hello and P Villard ldquoEmbankments reinforced by pilesand geosynthetics-Numerical and experimental studies dealingwith the transfer of load on the soil embankmentrdquo EngineeringGeology vol 106 no 1-2 pp 78ndash91 2009
[18] S W Abusharar J J Zheng B G Chen and J H Yin ldquoA sim-plified method for analysis of a piled embankment reinforcedwith geosyntheticsrdquo Geotextiles and Geomembranes vol 27 no1 pp 39ndash52 2009
[19] R Noorzad and M Omidvar ldquoSeismic displacement analysisof embankment dams with reinforced cohesive shellrdquo SoilDynamics and Earthquake Engineering vol 30 no 11 pp 1149ndash1157 2010
[20] T Matsumaru K Watanabe and J Isono ldquoApplication ofcement-mixed gravel reinforced by ground for soft groundimprovementrdquo in Proceedings of the 4th Asian Regional Confer-ence on Geosynthetics pp 380ndash385 Shanghai China June 2008
[21] Namdar and A A K Pelko ldquoSeismic evaluation of embank-ment shaking table test and finite element methodrdquo ThePacific Journal of Science and Technology vol 11 no 2 2010httpwwwakamaiuniversityusPJST
[22] L Wang G Zhang and J Zhang ldquoCentrifuge model tests ofgeotextile-reinforced soil embankments during an earthquakerdquoGeotextiles and Geomembranes vol 29 no 3 pp 222ndash232 2011
[23] H B Seed R T Wong I M Idriss and K Tokimatsu ldquoModuliand damping factors for dynamic analyses of cohesionless soilsrdquoJournal of Geotechnical Engineering vol 112 no 11 pp 1016ndash1032 1986
[24] B M Das Advanced Soil Mechanics CRC Press New York NYUSA 2013
[25] M J Griffin Handbook of Human Vibration Academic PressNew York NY USA 2012
[26] J Garnier C Gaudin S M Springman P J Culligan DJ Goodings and D Konig ldquoCatalogue of scaling laws andsimilitude questions in geotechnical centrifuge modellingrdquoInternational Journal of Physical Modelling in Geotechnics vol7 no 3 pp 1ndash23 2007
[27] A Fluent 120 Userrsquos Guide User Inputs for PorousMedia 2009
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Shock and Vibration
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International Journal of
Shock and Vibration 3
1006819
56833941
2729129533382
0102030405060708090
100
001 01 1 10 100
Fine
r (
)
Particle size (mm)
Laterite
(a)
Fine
r (
)
10097969388
6531
32661633
8172050102030405060708090
100
001 01 1 10 100Particle size (mm)
TDA
(b)Fi
ner (
)
10099328881
5966
37292204
1187340
102030405060708090
100
001 01 1 10 100
Particle size (mm)
MS
(c)
Figure 1 Distribution of gradation for different materials (a) Laterite (b) tire driven aggregate and (c) microsilica
00225 30626
006 16767
0065 10698
0045 2327400325 26357
000
5000
10000
15000
20000
25000
30000
35000
0 001 002 003 004 005 006 007 008
Sample 1Sample 4Sample 5
Sample 3Sample 2
Strain
Und
rain
ed sh
ear s
treng
th
Figure 2 Undrained shear strength in the triaxial compressionwithout measurement of pore pressure sample 1 to sample 5
0
2000
4000
6000
8000
10000
12000
14000
16000
Sample 1 Sample 2 Sample 3 Sample 4 Sample 5
1528372
982937
733618
25826214959El
astic
ity m
odul
us (k
Pa)
Figure 3 Distribution of elasticity modulus in samples one to five
1528372
982937733618
25826214959
693668871086
971862850591
55811653648
436286265589
02000400060008000
1000012000140001600018000
Sam
ple 1
Sam
ple 2
Sam
ple 3
Sam
ple 4
Sam
ple 5
Sam
ple 6
Sam
ple 7
Sam
ple 8
Sam
ple 9
Sam
ple 1
0
Sam
ple 1
1
Sam
ple 1
2
Sam
ple 1
3
Elas
ticity
mod
ulus
(kPa
)
Figure 4 Distribution of elasticity modulus in samples
Figure 8) However one of the major factors to design damis seepage controlling Therefore the permeability index wassignificantly improved by using more percentage of silicain this study In Figure 8 the minimum permeability wasobserved in sample 10 (167119864 minus 5 cms)
In terms of shear strength assessment using direct sheartest (small shear box apparatus) sample 10 indicated the bestperformance in order to increase both factors of cohesionand internal angle of friction Table 3 shows distribution ofcohesion and internal angle of friction in different samples
In order to estimate the damping ratio the nonlinearstress-strain characteristics of soils (Figure 9(a)) for anal-ysis purposes can be represented by bilinear relationships(Figure 9(b)) or multilinear relationships However the useof an equivalent linear viscoelastic analysis leads to similarresults Damping ratio depends on both areas as can be seen
4 Shock and Vibration
12000
10000
8000
6000
4000
2000
0
Sample 2 Sample 6 Sample 7
982937
693668
871086
(a)
12000
10000
8000
6000
4000
2000
0
Sample 3 Sample 8 Sample 9
733618
971862850591
(b)
Sample 4 Sample 10 Sample 11
7000
6000
5000
4000
3000
2000
1000
0
258262
55811
653648
(c)
Sample 5 Sample 12 Sample 13
5000
4000
3000
2000
1000
0
14959
436286
265589
(d)
Figure 5 Distribution of elasticity modulus (Kilo Pascal) for samples
377506
642489
327
593688 747
371 421514
333
61
012345678
Sam
ple 1
Sam
ple 2
Sam
ple 3
Sam
ple 4
Sam
ple 5
Sam
ple 6
Sam
ple 7
Sam
ple 8
Sam
ple 9
Sam
ple 1
0
Sam
ple 1
1
Sam
ple 1
2
Sam
ple 1
3
Figure 6 Distribution of area under the curve of stress-strain basedon unconfined test
with blue and red colors in this figure [24] This ratio can begiven as follows
Damping ratio = 119863 = (1
4120587)
lowast (Loop area
area under stress strain curve)
(1)
However the area under stress strain curve and hysteresisloop area can be computed according to Figure 9 Figure 10shows damping ratio for sample 1 and sample 10 respectivelyIt can be seen that this ratio was 1795 in laterite soil Interms of soil improvement the damping coefficient increasedto 2263 for sample 10 (7 TDA with 3 silica)
After discussing all tests in soil mechanic that werecarried out sample 10 shows the excellent performance inorder to reinforce dam Therefore IDL material was defined
Table 3 Distribution of cohesion and angle of internal friction indifferent samples
Sample Cohesion (KPa) Friction (degree)1 2518 30002 1317 35013 2234 31074 1305 36335 301 29396 1474 3367 1682 33588 1815 33479 1557 363110 2638 321011 3494 285712 2711 286713 1486 3252
by using sample 10 In the physical small dam modeling thismaterial to reinforce dam in different location was used
For small scale modeling the river sand was used forfoundation Table 4 presents sand properties It is importantto note that river sand included uniform size particlesbecause uniformity coefficient was less than five In additioncoefficient of curvature was less than oneThe soil is said to bewell graded if this value lies between one and threeThereforethis type of sand was selected in order to critically conditionfoundation
Shock and Vibration 5
01055
0093301137
0117701566
0207
0111201163
00675
01533 01544
00625
0081
0
005
01
015
02
025
Sam
ple 1
Sam
ple 2
Sam
ple 3
Sam
ple 4
Sam
ple 5
Sam
ple 6
Sam
ple 7
Sam
ple 8
Sam
ple 9
Sam
ple 1
0
Sam
ple 1
1
Sam
ple 1
2
Sam
ple 1
3
mv (average)
(m2M
N)
(a) Coefficient of volume compressibility
Sam
ple 1
Sam
ple 2
Sam
ple 3
Sam
ple 4
Sam
ple 5
Sam
ple 6
Sam
ple 7
Sam
ple 8
Sam
ple 9
Sam
ple 1
0
Sam
ple 1
1
Sam
ple 1
2
Sam
ple 1
3
4416
3395
36076
31893463
8159
3118
28552487
11922659
1596
2311
0102030405060708090
cv (average)
(m2y
ear)
(b) Coefficient of consolidation
Figure 7 Distribution of coefficients in samples for consolidation test (a) Coefficient of volume compressibility and (b) coefficient ofconsolidation
Sam
ple 1
Sam
ple 2
Sam
ple 3
Sam
ple 4
Sam
ple 5
Sam
ple 6
Sam
ple 7
Sam
ple 8
Sam
ple 9
Sam
ple 1
0
Sam
ple 1
1
Sam
ple 1
2
Sam
ple 1
3Permeability (cms)
000E + 00
500E minus 05
100E minus 04
150E minus 04
200E minus 04
250E minus 04
300E minus 04
129E minus 05345E minus 05
613E minus 05
710E minus 05
242E minus 04
386E minus 05
450E minus 05
257E minus 05
322E minus 05
167E minus 05
206E minus 05
234E minus 04
213E minus 04
Figure 8 Distribution of permeability for different samples
Table 4 Sand properties
Physical properties ValueSpecific gravity 2547Cohesion (KPa) 000Angle of internal friction (Degree) 35Modulus elasticity (KPa) 32460Maximum dry density (grcm3) 172Minimum dry density (grcm3) 136Density for 119868
119889
= 75 (grcm3) 1613Permeability (cms) 01Maximum size (mm) 200Minimum size (mm) 0075Uniformity coefficient 119862
119906
4375Coefficient of curvature 119862
119888
097
3 Small Scale Model on Vibrator Table
Physical models with scale parameter equal to 1100 weretested In order to research methodology for this purposesome aspects included characteristic of vibrator table dis-placement transducer data logger sinusoidal motion scaleparameter for static or dynamic condition free vibrationanalysis and physical modeling will be presented In this
study five small scale dams were tested as will be explainedin the next section
31 Vibrator Table In this study vibrating table 24-9112(CN-166) with respect to sinus motion was used Figure 11shows the vibrating desk that was cushioned with steeland seminoiseless electromagnetic vibrator with 3600 vpmoperating frequency In addition it has a separate controllerto vary vibrator amplitude in case of frequency capacitylimit 100Hz Table capacity was equal to 750 lbs (340 kg)Double amplitude range was located at 0002 inch (005mm)to 0015 inch (038mm) Actuator was an electromagneticvibrator over 100 lbs (4530 kg)The table was square in shapeand 30 inch (762mm) The table thickness was 333mm ofsteel In case of weight it was net 555 lbs (252 kg) and shippingwas 605 lbs (274 kg) Figure 11 illustrates the vibrator table forthis study
32 Displacement Transducerand Data Logger Displacementtransducer CDP-D was utilized with respect to dual isolatedIO ports By using transducer one set of cables for input andoutput was connected to the analog measuring instrumentand another set to the digital measuring instrument Withtwo different types of measuring equipment connected tothis transducer simultaneous measurements can be madewithout interference Figure 12(a) shows the displacementtransducer and Figure 12(b) shows the dimensions for trans-ducer CDP-100 Tomeasure displacement at both edges of thecrest in small scale modeling two transducers were installedIn terms of data record data logger or data recorder is anelectronic device that records data over time or in relation tolocation with either a built in instrument or a sensor or viaexternal instruments and sensors
Figure 12(c) illustrates the data logger that was used inthis study Based on device ability results were printed duringthe vibration duration After that results were classified byusing Excel program It should be noted that both transducersas mentioned previously were connected to this data logger(UCAM-70A) in order to record vertical displacement duringthe vibration In addition the sub step of vibration periodwas
6 Shock and Vibration
Stress
Strain
(a)
Stress
Strain
(b)
Figure 9 Damping definition and hysteretic and equivalent bilinear stress-strain relationships for soil (a) stress-strain curves (b) bilinearidealization [23]
400
300
200
100
0
minus100
minus200
minus300
minus400
minus003 minus002 minus001 0 001 002 003
0020
00168
00225Stress (kPa)
Strain
Blue area = 377
Loop area = 850
Damping = 01795
Hysteresis loop-sample 1
(a)
250200150100500
minus50minus100minus150minus200minus250
minus006 minus004 minus002 0 002 004 006
00425
0034
00404
Stress (kPa)
Strain
Hysteresis loop-sample 10
Blue area = 421Loop area = 1197
Damping = 02263
(b)
Figure 10 Estimation of damping ratio (a) sample 1 and (b) sample 10
Figure 11 Vibrator table
equal to two seconds based on device ability with respect toprint
33 Sinusoidal Vibrate Loading There is a mathematicalrelationship between frequency displacement velocity andacceleration for sinusoidalmotion according to considerationof the peak value for them The relationship is such that ifany two of the four variables are known the other two can becalculated Table 5 shows all equations that were provided inthis context [25]
Table 5 Conversion for peak value in sinusoidal motion displace-ment (X) velocity (V) acceleration (A) and frequency (f )
Displacement X Velocity V Acceleration A
Displacement X 119883 = 119883 119883 =119881
2120587119891119883 =
119860
(2120587119891)2
Velocity V 119881 = 2120587119891119883 119881 = 119881 119881 =119860
2120587119891
Acceleration A 119860 = (2120587119891)2
119883 119860 = 2120587119891119881 119860 = 119860
119866 in these formulas is not gravity acceleration It is aconstant for calculation within different systems Respec-tively for metric imperial and Si 119866 is 980665ms23860885827 ins2 and 100ms2
Since themotion is sinusoidal the displacement velocityand acceleration are changing sinusoidal trend Howeverthey are not in the same phase The phase relationshipbetween displacement velocity and acceleration is that veloc-ity is 90∘ out of phase with acceleration and displacement is180∘ out of phase with acceleration
Shock and Vibration 7
(a)
CDP-D
12060110120601D
10
120601E
C A
120601BInputoutput 1Inputoutput 2
2 inputoutput cables
Dimensions
TypeCDP-50-D
A B C D E
165 335 65 5 10
(b)
(c)
Figure 12 Transducer and data logger (a) Displacement transducer CDP-100 (b) dimension of displacement transducer (CDP-100) and (c)data logger UCAM-70A
155
minus5minus15
20100
minus10minus20
25155
minus5minus15minus25
Displacement 13mm peak
Velocity 16336ms peak
Acceleration 2090gn peak
Figure 13 20Hz sinusoidal motion
In other words when displacement is at a maximumvelocity is at a minimum and acceleration is at a maximumIt should be noted that 1 119892
119899
= 980665ms2 = 32174 fts2 =3860886 ins2 Figure 13 shows the example of displacementdistribution with velocity and acceleration while the fre-quency of sinusoidal motion is twenty hertz
34 Scaling Laws In case of the scale parameter the scalefactor can be used according to
119909lowast
=119909119898
119909119901
(2)
The subscript 119898 represents ldquomodelrdquo and the subscript 119901represents ldquoprototyperdquo and 119909lowast represents the scale factor forthe quantity 119909 [26]
k
mx
Figure 14 Mass spring system
Figure 15 Free mesh
The reason for spinning a model on a centrifuge is toenable small scale models to feel the same effective stresses asa full scale prototype This goal can be stated mathematicallyas
1205901015840119909
=1205901015840
119898
1205901015840
119901
= 1 (3)
where the asterisk represents the scaling factor for thequantity 1205901015840
119898
is the effective stress in the model and 1205901015840119901
is theeffective stress in the prototype
8 Shock and Vibration
Nodal solutionStep = 1
UX (Avg)RSYS = 0
DMX = 0288E minus 03
SMX = 0271E minus 04
Sub = 1X
Y
Z
MN
MX
minus0271E
minus04
minus0210E
minus04
minus0150E
minus04
minus0902Eminus05
minus0301Eminus05
0301Eminus05
0902Eminus05
0150E
minus04
0210E
minus04
0271E
minus04
SMN = minus0271E minus 04
Freq = 0229855
(a)
Nodal solutionStep = 1
Sub = 1
UY (Avg)RSYS = 0
DMX = 0288E minus 03
SMX = 0126E minus 03
X
Y
Z
MN
MX
minus0971E
minus04
minus0125E
minus03
minus0692E
minus04
minus0413Eminus04
minus0134Eminus04
0145Eminus04
0423E
minus04
0702E
minus04
0981E
minus04
0126E
minus03
SMN = minus0125E minus 03
Freq = 0229855
(b)
X
Y
Z MN
MX
0
0287E
minus04
0575E
minus04
0862Eminus04
0115Eminus03
0144Eminus03
0172Eminus03
0201E
minus03
0230E
minus03
0259E
minus03
Nodal solutionStep = 1
UZ (Avg)RSYS = 0
DMX = 0288E minus 03
SMX = 0259E minus 03
Sub = 1
Freq = 0229855
(c)
X
Y
Z
MX0
0320E
minus04
0639E
minus04
0959Eminus04
0128Eminus03
0160Eminus03
0192Eminus03
0224E
minus03
0256E
minus03
0288E
minus03
Nodal solutionStep = 1
Sub = 1
USUM (Avg)RSYS = 0
DMX = 0288E minus 03
SMX = 0288E minus 03
MN
Freq = 0229855
(d)
Figure 16 Mode shape 1 (a) horizontal displacement (b) vertical displacement (c) lateral displacement and (d) total displacement
In soil mechanics the vertical effective stress 1205901015840 forexample is typically calculated by
1205901015840
= 120590119905
minus 119906 (4)
where 120590119905 and 119906 are total stress and pore pressure respectivelyFor a uniform layer with no pore pressure the total verticalstress at a depth119867may be calculated by
120590119905
= 120588119892119867 (5)
where 120588 represents the density of the layer and 119892 representsgravity In the conventional form of centrifugemodeling [26]it is typical that the same materials are used in the model andprototype therefore the densities are the same in model andprototype that is
120588lowast
= 1 (6)
Furthermore in conventional centrifugemodeling all lengthsare scaled by the same factor 119871lowast To produce the same stressin the model as in the prototype we thus require
120588lowast
119892lowast
119867lowast
= 1119892lowast
119871lowast
= 1 (7)
It may be rewritten as
119892lowast
=1
119871lowast
(8)
The above scaling law states that if lengths in the model arereduced by some factor 119899 then gravitational accelerationsmust be increased by the same factor 119899 in order to preserveequal stresses in model and prototype
Shock and Vibration 9
1650
950
500 5200 500
1000
1000785
Laterite
Water
Sand
(a)
1650
950
500 5200 500
1000
1000785
Laterite
Water
Sand
(b)
1650
950
500 5200 500
1000
1000785
Laterite
Water
Sand
(c)
1650
950
500 5200 500
1000
1000785 Water
Sand
Laterite reinforced
(d)
1650
950
1000
1000785
Laterite
Water
Sand
500 5200 500
(e)
Figure 17 Model introducing ((a) (b) (c) (d) and (e)) for small dam (cm) (119878 = 1100)
For dynamic problems where gravity and accelerationsare important all accelerations must scale as gravity is scaledthat is
119886lowast
= 119892lowast
=1
119871lowast
(9)
Since acceleration has units of 1198711198792 it is required that
119886lowast
=119871lowast
1198792
(10)
Hence it is required that
1
119871lowast
=119871lowast
1198792
or 119879lowast
= 119871lowast
(11)
Frequency has units of inverse of time and velocity has unitsof length per time so for dynamic problems we also obtain
119891lowast
=1
119871lowast
Vlowast =119871lowast
119879lowast
= 1 (12)
For model tests involving dynamics the conflict in time scalefactors may be resolved by scaling the permeability of the soil[26]
35 Free Vibration Analysis In dynamic assessment freevibration analysis is the base of study In fact the distributionof frequency in the different vibrationmode can be computedby the application of modal analysis based on finite-elementmethod (FEM) It is worth mentioning that this analysis isperfectly related to the mass and spring In case of the mass-spring-damper system the first assumption is negligibleabout damping effect Therefore there is not any externalforce on mass in this state The force applied to the massby the spring is proportional to the amount of the springthat is stretched ldquo119909rdquo (it can be assumed that spring isalready compressed due to the weight of the mass) Theproportionality constant (119896) is spring stiffness (see Figure 14)The unit measurement is force divided by distance (kgm)
10 Shock and Vibration
(a) (b)
(c) (d)
Figure 18 Small scale dam (a) Dam perspective with two LVDT (b) soil compaction with roller (c) dam section with index network and(d) dam with tank before vibration
The negative sign indicates that force is always opposingthe motion of the mass attached to it according to thefollowing equation
119865119904
= minus119896119909 (13)
The force generated by the mass is proportional to theacceleration of the mass as given by Newtonrsquos second law ofmotion
sum119865 = 119898119886 = 119898 = 1198981198892
119909
1198891199052
(14)
The sumof the forces on themass then generates this ordinarydifferential equation
119898 + 119896119909 = 0 (15)
Assuming that the initial vibration can be started by stretch-ing and releasing the spring with distance (119860) the solution tothe above equation that describes the motion of mass can beseen in the following equation
119909 (119905) = 119860 cos (2120587119891119899
119905) (16)
This solution shows that it will oscillate with simple harmonicmotion that has amplitude of (119860) and a frequency (119891
119899
) Thenumber (119891
119899
) is called the undamped natural frequency Forthe simple mass-spring system frequency is given by
119891119899
=1
2120587
radic119896
119898 (17)
However the relation between frequency and vibrationperiod is always reverse Consider
119879 =1
119891 (18)
In terms of the measurement unit the vibration periodand frequency were according to seconds and hertz It isworth noting that the dominant frequency is the minimumfrequency to produce maximum vibration period
4 Numerical Analysis
In terms of numerical analysismodal analysis was carried outby using ANSYS program in this study to compute dominantfrequency for small scale model regarding 3D analysis Thisprogram is one of the famous software programs with respectto finite-elementmethod (FEM) In particular this software isone of the universal programs with high level of the ability fordifferent analyses A strong ability to compute free vibrationanalysis is possible with modal analysis [27]
41 Elements and Meshing Process To select element basedon Help menu solid 8 nodes 183 (3D) were used for thispurpose Figure 15 shows the mapped mesh for numericalmodeling In this figure 23956 elements and 35457 nodes inmodels were used for free vibration analysis According tothis condition free vibration analysis to access frequency indifferent vibration modes was carried out as results can bediscussed in the next section
Shock and Vibration 11
0 20 40 60 80 100 1200
minus01
minus02
minus03
minus04
minus05
minus06
62 minus029
90 minus048
Time (s)
Disp
lace
men
t (m
m)
Time (s)0 10 20 30 40 50 60 70 80 90 100 110 120
03
025
02
015
01
005
0
Rela
tive
disp
lace
men
t (m
m)
96 024
Model A
0 20 40 60 80 100 120
Time (s)
Disp
lace
men
t (m
m) 2
15
1
05
0
minus05
minus1
minus15
84 15
104 minus064
Time (s)0 10 20 30 40 50 60 70 80 90 100 110 120
Rela
tive
disp
lace
men
t (m
m) 25
2
15
1
05
0
minus05
minus1
104 213
Model B
0 20 40 60 80 100 120
Time (s)
Disp
lace
men
t (m
m)
01201008006004002
0minus002minus004
108 01
108 006
Time (s)
0 10 20 30 40 50 60 70 80 90 100 110 120
Rela
tive
disp
lace
men
t (m
m)
007
006
005
004
003
002
001
0
8 006
Model C
Time (s)0 10 20 30 40 50 60 70 80 90 100 110 120
Rela
tive
disp
lace
men
t (m
m)
0201501005
0minus005minus01minus015minus02
90 017
26 minus017
0 20 40 60 80 100 120
Time (s)
Disp
lace
men
t (m
m) 015
01005
0
minus01minus015
minus005
minus02minus025
114 minus007116 minus022
Model DTime (s)
Disp
lace
men
t (m
m)
01
0
minus01
minus02
minus03
minus04
104 minus011
102 minus033
0 20 40 60 80 100 120
Up streamDown stream
Time (s)
0 10 20 30 40 50 60 70 80 90 100 110 120
Rela
tive
disp
lace
men
t (m
m)
03
025
02
015
01
0
005
86 025
Model E
Figure 19 Vertical displacement in both edges of the crest in models with relative displacement
12 Shock and Vibration
(a) (b) (c)
Figure 20 Damage in the first model (Model A)
(a) (b)
(c) (d)
Figure 21 Damage in the second model (Model B)
42 Free Vibration Analysis and Dominant Frequency Interms of modal analysis the free vibration analysis was cal-culated by ANSYS program Figure 16 shows displacement inthree directions of model and total displacement in the firstvibration mode because based on distribution of frequencyin the first mode to fifth mode it is important to note thatthe minimum frequency (022986Hz) was observed in thefirst vibration mode It means that the vibration period wasmaximum and critical in this mode
Distribution of frequency in different vibration modesindicated that this value was respectively obtained at026257Hz 028387Hz and 030135Hz in the vibration shapemodes 2 to 4
5 Results and Discussion Based on PhysicalSmall Scale Modeling
In order to find the best location of reinforcement in damfive small dams with different locations of reinforcementusing IDL material were vibrated by dominant frequency
(22986Hz) with respect to resonance condition Figure 17shows five small scale dams (Models (a) (b) (c) and (d))it is obvious that models have the same dimension In thisfigure the reinforced area was illustrated with a hatch areaFor example Model (d) indicated that all dam body wasreinforced For this purpose one steel box for modeling wasused This box made by five sheets of Plexiglas with 20mmthickness One of them was in the base of model The levelof reservoir was 75 of the dam height The scale parameterwas 1100 Itmeans thatmodel was one hundred times smallerthan prototypeThedamheightwas 227meter in reality but itwas made 227 cm in physical model In addition small scalemodeling was coupled by foundation Foundation materialwas dense sand with 75 relative density Sand propertieswere mentioned in soil mechanic test Figure 18 shows somedetails including dam perspective soil compaction networkindex and reservoir In this Figure two LVDT on the middleof model at the both edges of the crest were installed Inorder to achieve support one steel frame and one steel beamwere applied (see Figure 18(a)) However both LVDT wereconnected to data logger device by specific cables In terms
Shock and Vibration 13
(a) (b)
Figure 22 Damage in the third model (Model C)
of compaction soil for each layer the steel roller used wasselected by trial error methodWoodmolding with respect tocontrol slope via network index was used In order to avoidabsorption of soil water content both the described moldswere just soaked by water before use For tank purpose smallscale models were filled up by water with very slow rate
After vibration equal to two minutes for all modelsthe vertical displacement for both slopes such as upstreamand downstream were printed With respect to use of Excelprogram Figure 19 shows the distribution of vertical displace-ment in both edges in the middle of the crest and relativedisplacement in all models It was obvious that distributionof the vertical displacement indicated a same trend for bothmodels such as A and E In both models displacement valueswere negative during the vibration It means that both ofthem were in uplift condition In this figure also maximumandminimum peak of the relative displacement respectivelyoccurred in Models B and C with 213mm and 006mm It isalso worth noting that this value was at convergence positionfor Models A and E with 024mm and 025mm respectively
In terms of damage location in models Figure 20 showsthe damage in Model A which occurred at upstream anddownstream The level of damage was greater in upstream Itwas very sensible occurrence in case of hydrodynamic pres-sure along the vibration Also in this figure the maximumlongitudes cracks (see line C) were observed near to themiddle of dam at the crest For damage at downstream thetransverse cracks significantly occurred in dam toe
Figure 21 shows Model B that was damaged after vibra-tion It can be observed that dam was significantly damagedin some locations such as crest and surfaces Body cracks andfailure process dramatically occurred in both areas near toabutments Also in this figure one transverse crack in themiddle of the crest was seen (see Figure 20(c)) This damagewas significantly repeated at upstream in Model C but itwas placed in dam toe and it can be seen in Figure 22 Inaddition Model D was damaged in three places such as bothabutments and the middle of the upstream Figure 23 showsModel D that was damaged in toe Briefly all four modelswere damaged as discussed previously On the other handa successful way in order to remove damage was obtained inModel E as shown in Figure 24 Figure 24 shows that model
Figure 23 Damage in the fourth model (Model D)
was safe after vibration without any damage In this figurethe reinforced blanket layer using IDLmaterial was indicatedby red circles between dam and foundation In addition itwas very important to note that both surfaces were safe anddam was stable under severe seismic loading like resonancemotion In fact a good absorption of energy with respectto increase of damping was found by using IDL In case ofusing this technique displacement in both edges of the crestwith negative value indicated the uplift situation Moreoverrelative displacement was like the first model Thereforedam behavior before and after reinforcement was similar forboth distributions of displacement Nevertheless Model Ewas successful to remove damage with respect to high levelof damping in blanket layer In fact this model shows theexcellent performance in earth dams when the blanket layerwas expanded below tank
Finally blanket layer using isolator damper layer (IDL)below dam and tank is a good recommendation for earthdams in seismic zonewhen reinforced thickness is one-fourthof damheight As recommended optimization of thickness inthis method is the next study
6 Conclusion
In this study the earth dam performance under severeseismic motion such as resonance was evaluated by usingblanket layer (IDL) With respect to soil mechanic testthe optimum mixture for IDL was designed IDL powderwas made by using some materials Main material was alocal soil (laterite) with 90 and additives such as TDA
14 Shock and Vibration
(a) (b)
(c) (d)
Figure 24 Dam stabilization in the fifth model (Model E)
(tire derived aggregate with 7) and MS (microsilica) with3 were used This material was utilized to reinforce damin small scale physical modeling According to numericalanalysis the dominant frequency (02298Hz) in order tohave maximum effect for modeling vibration was computedBy using this frequency for physical modeling the damagelocation and distribution of vertical displacement at bothedges of the crest in the middle of small dams for five smallmodel with scale 1100 were discussed As results the bestperformance in order to remove damages was obviouslyobserved in Model E while other models were dramaticallydamaged in some locations such as upstream downstreamand crest In addition the thickness of blanket layer in thismodel was one-fourth of dam height Finally this model is anovel method to reinforce dam under strong earthquake likeresonance phenomena recommended for earth dam designin seismic zone
Conflict of Interests
The authors declare that there is no conflict of interestsregarding the publication of this paper
Acknowledgment
This study ismade possible by the support of the InternationalDoctorate Fellowship of Universiti Teknologi Malaysia andit is very much appreciated
References
[1] M Zeghal and A M Abdel-Ghaffar ldquoAnalysis of behavior ofearth dam using strong-motion earthquakes recordsrdquo Journalof Geotechnical Engineering vol 118 no 2 pp 266ndash277 1992
[2] V Gikas andM Sakellariou ldquoSettlement analysis of theMornosearth dam (Greece) evidence from numerical modeling andgeodetic monitoringrdquo Engineering Structures vol 30 no 11 pp3074ndash3081 2008
[3] R Verdugo N Sitar J D Frost et al ldquoSeismic performanceof earth structures during the February 2010 Maule Chileearthquake dams levees tailings dams and retaining wallsrdquoEarthquake Spectra vol 28 no 1 pp S75ndashS96 2012
[4] Y Parish and F N Abadi ldquoDynamic behaviour of earth damsfor variation of earth material stiffnessrdquo Proceedings of WorldAcademy of Science Engineering and Technology vol 50 pp606ndash611 2009
[5] T G Berhe X T Wang and W Wu ldquoNumerical investigationinto the arrangement of clay core on the seismic performanceof earth damsrdquo in Proceedings of the GeoShanghai InternationalConference on Soil Dynamics and Earthquake Engineering pp131ndash138 ASCE June 2010
[6] Z F Xia G L Ye J HWang B Ye and F Zhang ldquoFully couplednumerical analysis of repeated shake-consolidation process ofearth embankment on liquefiable foundationrdquo Soil Dynamicsand Earthquake Engineering vol 30 no 11 pp 1309ndash1318 2010
[7] X J Kong Y Zhou B Xu and D G Zou ldquoAnalysis on seismicfailure mechanism of Zipingpu dam and several reflections ofaseismic design for high rock-fill damrdquo in Proceedings of theEarth and Space pp 3177ndash3189 March 2010
Shock and Vibration 15
[8] A BayraktarM E Kartal and S Adanur ldquoThe effect of concreteslabrockfill interface behavior on the earthquake performanceof a CFR damrdquo International Journal of Non-Linear Mechanicsvol 46 no 1 pp 35ndash46 2011
[9] R P Piao A H Rippe B Myers and K W Lane ldquoEarthdam liquefaction and deformation analysis using numericalmodelingrdquo in Proceedings of the GeoCongress pp 1ndash6 March2006
[10] A W Elgamal ldquoThree-dimensional seismic analysis of la villitadamrdquo Journal of Geotechnical Engineering vol 118 no 12 pp1937ndash1958 1992
[11] B Gordan and B A Azlan ldquoEffect of material properties inCFRD tailing-embankment bridge during a strong earthquakerdquoCaspian Journal of Applied Sciences Research vol 2 no 11 pp61ndash72 2013
[12] A Papalou and J Bielak ldquoSeismic elastic response of Earthdams with canyon interactionrdquo Journal of Geotechnical andGeoenvironmental Engineering vol 127 no 5 pp 446ndash453 2001
[13] Y Yu L Xie and B Zhang ldquoStability of earth-rockfill damsinfluence of geometry on the three-dimensional effectrdquo Com-puters and Geotechnics vol 32 no 5 pp 326ndash339 2005
[14] L H Mejia and H B Seed ldquoComparison of 2-D and 3-D dynamic analyses of earth damsrdquo Journal of GeotechnicalEngineering vol 109 no 11 pp 1383ndash1398 1983
[15] J L Borges ldquoThree-dimensional analysis of embankmentson soft soils incorporating vertical drains by finite elementmethodrdquoComputers andGeotechnics vol 31 no 8 pp 665ndash6762004
[16] A Yildiz ldquoNumerical analyses of embankments on PVDimproved soft claysrdquo Advances in Engineering Software vol 40no 10 pp 1047ndash1055 2009
[17] B Le Hello and P Villard ldquoEmbankments reinforced by pilesand geosynthetics-Numerical and experimental studies dealingwith the transfer of load on the soil embankmentrdquo EngineeringGeology vol 106 no 1-2 pp 78ndash91 2009
[18] S W Abusharar J J Zheng B G Chen and J H Yin ldquoA sim-plified method for analysis of a piled embankment reinforcedwith geosyntheticsrdquo Geotextiles and Geomembranes vol 27 no1 pp 39ndash52 2009
[19] R Noorzad and M Omidvar ldquoSeismic displacement analysisof embankment dams with reinforced cohesive shellrdquo SoilDynamics and Earthquake Engineering vol 30 no 11 pp 1149ndash1157 2010
[20] T Matsumaru K Watanabe and J Isono ldquoApplication ofcement-mixed gravel reinforced by ground for soft groundimprovementrdquo in Proceedings of the 4th Asian Regional Confer-ence on Geosynthetics pp 380ndash385 Shanghai China June 2008
[21] Namdar and A A K Pelko ldquoSeismic evaluation of embank-ment shaking table test and finite element methodrdquo ThePacific Journal of Science and Technology vol 11 no 2 2010httpwwwakamaiuniversityusPJST
[22] L Wang G Zhang and J Zhang ldquoCentrifuge model tests ofgeotextile-reinforced soil embankments during an earthquakerdquoGeotextiles and Geomembranes vol 29 no 3 pp 222ndash232 2011
[23] H B Seed R T Wong I M Idriss and K Tokimatsu ldquoModuliand damping factors for dynamic analyses of cohesionless soilsrdquoJournal of Geotechnical Engineering vol 112 no 11 pp 1016ndash1032 1986
[24] B M Das Advanced Soil Mechanics CRC Press New York NYUSA 2013
[25] M J Griffin Handbook of Human Vibration Academic PressNew York NY USA 2012
[26] J Garnier C Gaudin S M Springman P J Culligan DJ Goodings and D Konig ldquoCatalogue of scaling laws andsimilitude questions in geotechnical centrifuge modellingrdquoInternational Journal of Physical Modelling in Geotechnics vol7 no 3 pp 1ndash23 2007
[27] A Fluent 120 Userrsquos Guide User Inputs for PorousMedia 2009
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Shock and Vibration
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International Journal of
4 Shock and Vibration
12000
10000
8000
6000
4000
2000
0
Sample 2 Sample 6 Sample 7
982937
693668
871086
(a)
12000
10000
8000
6000
4000
2000
0
Sample 3 Sample 8 Sample 9
733618
971862850591
(b)
Sample 4 Sample 10 Sample 11
7000
6000
5000
4000
3000
2000
1000
0
258262
55811
653648
(c)
Sample 5 Sample 12 Sample 13
5000
4000
3000
2000
1000
0
14959
436286
265589
(d)
Figure 5 Distribution of elasticity modulus (Kilo Pascal) for samples
377506
642489
327
593688 747
371 421514
333
61
012345678
Sam
ple 1
Sam
ple 2
Sam
ple 3
Sam
ple 4
Sam
ple 5
Sam
ple 6
Sam
ple 7
Sam
ple 8
Sam
ple 9
Sam
ple 1
0
Sam
ple 1
1
Sam
ple 1
2
Sam
ple 1
3
Figure 6 Distribution of area under the curve of stress-strain basedon unconfined test
with blue and red colors in this figure [24] This ratio can begiven as follows
Damping ratio = 119863 = (1
4120587)
lowast (Loop area
area under stress strain curve)
(1)
However the area under stress strain curve and hysteresisloop area can be computed according to Figure 9 Figure 10shows damping ratio for sample 1 and sample 10 respectivelyIt can be seen that this ratio was 1795 in laterite soil Interms of soil improvement the damping coefficient increasedto 2263 for sample 10 (7 TDA with 3 silica)
After discussing all tests in soil mechanic that werecarried out sample 10 shows the excellent performance inorder to reinforce dam Therefore IDL material was defined
Table 3 Distribution of cohesion and angle of internal friction indifferent samples
Sample Cohesion (KPa) Friction (degree)1 2518 30002 1317 35013 2234 31074 1305 36335 301 29396 1474 3367 1682 33588 1815 33479 1557 363110 2638 321011 3494 285712 2711 286713 1486 3252
by using sample 10 In the physical small dam modeling thismaterial to reinforce dam in different location was used
For small scale modeling the river sand was used forfoundation Table 4 presents sand properties It is importantto note that river sand included uniform size particlesbecause uniformity coefficient was less than five In additioncoefficient of curvature was less than oneThe soil is said to bewell graded if this value lies between one and threeThereforethis type of sand was selected in order to critically conditionfoundation
Shock and Vibration 5
01055
0093301137
0117701566
0207
0111201163
00675
01533 01544
00625
0081
0
005
01
015
02
025
Sam
ple 1
Sam
ple 2
Sam
ple 3
Sam
ple 4
Sam
ple 5
Sam
ple 6
Sam
ple 7
Sam
ple 8
Sam
ple 9
Sam
ple 1
0
Sam
ple 1
1
Sam
ple 1
2
Sam
ple 1
3
mv (average)
(m2M
N)
(a) Coefficient of volume compressibility
Sam
ple 1
Sam
ple 2
Sam
ple 3
Sam
ple 4
Sam
ple 5
Sam
ple 6
Sam
ple 7
Sam
ple 8
Sam
ple 9
Sam
ple 1
0
Sam
ple 1
1
Sam
ple 1
2
Sam
ple 1
3
4416
3395
36076
31893463
8159
3118
28552487
11922659
1596
2311
0102030405060708090
cv (average)
(m2y
ear)
(b) Coefficient of consolidation
Figure 7 Distribution of coefficients in samples for consolidation test (a) Coefficient of volume compressibility and (b) coefficient ofconsolidation
Sam
ple 1
Sam
ple 2
Sam
ple 3
Sam
ple 4
Sam
ple 5
Sam
ple 6
Sam
ple 7
Sam
ple 8
Sam
ple 9
Sam
ple 1
0
Sam
ple 1
1
Sam
ple 1
2
Sam
ple 1
3Permeability (cms)
000E + 00
500E minus 05
100E minus 04
150E minus 04
200E minus 04
250E minus 04
300E minus 04
129E minus 05345E minus 05
613E minus 05
710E minus 05
242E minus 04
386E minus 05
450E minus 05
257E minus 05
322E minus 05
167E minus 05
206E minus 05
234E minus 04
213E minus 04
Figure 8 Distribution of permeability for different samples
Table 4 Sand properties
Physical properties ValueSpecific gravity 2547Cohesion (KPa) 000Angle of internal friction (Degree) 35Modulus elasticity (KPa) 32460Maximum dry density (grcm3) 172Minimum dry density (grcm3) 136Density for 119868
119889
= 75 (grcm3) 1613Permeability (cms) 01Maximum size (mm) 200Minimum size (mm) 0075Uniformity coefficient 119862
119906
4375Coefficient of curvature 119862
119888
097
3 Small Scale Model on Vibrator Table
Physical models with scale parameter equal to 1100 weretested In order to research methodology for this purposesome aspects included characteristic of vibrator table dis-placement transducer data logger sinusoidal motion scaleparameter for static or dynamic condition free vibrationanalysis and physical modeling will be presented In this
study five small scale dams were tested as will be explainedin the next section
31 Vibrator Table In this study vibrating table 24-9112(CN-166) with respect to sinus motion was used Figure 11shows the vibrating desk that was cushioned with steeland seminoiseless electromagnetic vibrator with 3600 vpmoperating frequency In addition it has a separate controllerto vary vibrator amplitude in case of frequency capacitylimit 100Hz Table capacity was equal to 750 lbs (340 kg)Double amplitude range was located at 0002 inch (005mm)to 0015 inch (038mm) Actuator was an electromagneticvibrator over 100 lbs (4530 kg)The table was square in shapeand 30 inch (762mm) The table thickness was 333mm ofsteel In case of weight it was net 555 lbs (252 kg) and shippingwas 605 lbs (274 kg) Figure 11 illustrates the vibrator table forthis study
32 Displacement Transducerand Data Logger Displacementtransducer CDP-D was utilized with respect to dual isolatedIO ports By using transducer one set of cables for input andoutput was connected to the analog measuring instrumentand another set to the digital measuring instrument Withtwo different types of measuring equipment connected tothis transducer simultaneous measurements can be madewithout interference Figure 12(a) shows the displacementtransducer and Figure 12(b) shows the dimensions for trans-ducer CDP-100 Tomeasure displacement at both edges of thecrest in small scale modeling two transducers were installedIn terms of data record data logger or data recorder is anelectronic device that records data over time or in relation tolocation with either a built in instrument or a sensor or viaexternal instruments and sensors
Figure 12(c) illustrates the data logger that was used inthis study Based on device ability results were printed duringthe vibration duration After that results were classified byusing Excel program It should be noted that both transducersas mentioned previously were connected to this data logger(UCAM-70A) in order to record vertical displacement duringthe vibration In addition the sub step of vibration periodwas
6 Shock and Vibration
Stress
Strain
(a)
Stress
Strain
(b)
Figure 9 Damping definition and hysteretic and equivalent bilinear stress-strain relationships for soil (a) stress-strain curves (b) bilinearidealization [23]
400
300
200
100
0
minus100
minus200
minus300
minus400
minus003 minus002 minus001 0 001 002 003
0020
00168
00225Stress (kPa)
Strain
Blue area = 377
Loop area = 850
Damping = 01795
Hysteresis loop-sample 1
(a)
250200150100500
minus50minus100minus150minus200minus250
minus006 minus004 minus002 0 002 004 006
00425
0034
00404
Stress (kPa)
Strain
Hysteresis loop-sample 10
Blue area = 421Loop area = 1197
Damping = 02263
(b)
Figure 10 Estimation of damping ratio (a) sample 1 and (b) sample 10
Figure 11 Vibrator table
equal to two seconds based on device ability with respect toprint
33 Sinusoidal Vibrate Loading There is a mathematicalrelationship between frequency displacement velocity andacceleration for sinusoidalmotion according to considerationof the peak value for them The relationship is such that ifany two of the four variables are known the other two can becalculated Table 5 shows all equations that were provided inthis context [25]
Table 5 Conversion for peak value in sinusoidal motion displace-ment (X) velocity (V) acceleration (A) and frequency (f )
Displacement X Velocity V Acceleration A
Displacement X 119883 = 119883 119883 =119881
2120587119891119883 =
119860
(2120587119891)2
Velocity V 119881 = 2120587119891119883 119881 = 119881 119881 =119860
2120587119891
Acceleration A 119860 = (2120587119891)2
119883 119860 = 2120587119891119881 119860 = 119860
119866 in these formulas is not gravity acceleration It is aconstant for calculation within different systems Respec-tively for metric imperial and Si 119866 is 980665ms23860885827 ins2 and 100ms2
Since themotion is sinusoidal the displacement velocityand acceleration are changing sinusoidal trend Howeverthey are not in the same phase The phase relationshipbetween displacement velocity and acceleration is that veloc-ity is 90∘ out of phase with acceleration and displacement is180∘ out of phase with acceleration
Shock and Vibration 7
(a)
CDP-D
12060110120601D
10
120601E
C A
120601BInputoutput 1Inputoutput 2
2 inputoutput cables
Dimensions
TypeCDP-50-D
A B C D E
165 335 65 5 10
(b)
(c)
Figure 12 Transducer and data logger (a) Displacement transducer CDP-100 (b) dimension of displacement transducer (CDP-100) and (c)data logger UCAM-70A
155
minus5minus15
20100
minus10minus20
25155
minus5minus15minus25
Displacement 13mm peak
Velocity 16336ms peak
Acceleration 2090gn peak
Figure 13 20Hz sinusoidal motion
In other words when displacement is at a maximumvelocity is at a minimum and acceleration is at a maximumIt should be noted that 1 119892
119899
= 980665ms2 = 32174 fts2 =3860886 ins2 Figure 13 shows the example of displacementdistribution with velocity and acceleration while the fre-quency of sinusoidal motion is twenty hertz
34 Scaling Laws In case of the scale parameter the scalefactor can be used according to
119909lowast
=119909119898
119909119901
(2)
The subscript 119898 represents ldquomodelrdquo and the subscript 119901represents ldquoprototyperdquo and 119909lowast represents the scale factor forthe quantity 119909 [26]
k
mx
Figure 14 Mass spring system
Figure 15 Free mesh
The reason for spinning a model on a centrifuge is toenable small scale models to feel the same effective stresses asa full scale prototype This goal can be stated mathematicallyas
1205901015840119909
=1205901015840
119898
1205901015840
119901
= 1 (3)
where the asterisk represents the scaling factor for thequantity 1205901015840
119898
is the effective stress in the model and 1205901015840119901
is theeffective stress in the prototype
8 Shock and Vibration
Nodal solutionStep = 1
UX (Avg)RSYS = 0
DMX = 0288E minus 03
SMX = 0271E minus 04
Sub = 1X
Y
Z
MN
MX
minus0271E
minus04
minus0210E
minus04
minus0150E
minus04
minus0902Eminus05
minus0301Eminus05
0301Eminus05
0902Eminus05
0150E
minus04
0210E
minus04
0271E
minus04
SMN = minus0271E minus 04
Freq = 0229855
(a)
Nodal solutionStep = 1
Sub = 1
UY (Avg)RSYS = 0
DMX = 0288E minus 03
SMX = 0126E minus 03
X
Y
Z
MN
MX
minus0971E
minus04
minus0125E
minus03
minus0692E
minus04
minus0413Eminus04
minus0134Eminus04
0145Eminus04
0423E
minus04
0702E
minus04
0981E
minus04
0126E
minus03
SMN = minus0125E minus 03
Freq = 0229855
(b)
X
Y
Z MN
MX
0
0287E
minus04
0575E
minus04
0862Eminus04
0115Eminus03
0144Eminus03
0172Eminus03
0201E
minus03
0230E
minus03
0259E
minus03
Nodal solutionStep = 1
UZ (Avg)RSYS = 0
DMX = 0288E minus 03
SMX = 0259E minus 03
Sub = 1
Freq = 0229855
(c)
X
Y
Z
MX0
0320E
minus04
0639E
minus04
0959Eminus04
0128Eminus03
0160Eminus03
0192Eminus03
0224E
minus03
0256E
minus03
0288E
minus03
Nodal solutionStep = 1
Sub = 1
USUM (Avg)RSYS = 0
DMX = 0288E minus 03
SMX = 0288E minus 03
MN
Freq = 0229855
(d)
Figure 16 Mode shape 1 (a) horizontal displacement (b) vertical displacement (c) lateral displacement and (d) total displacement
In soil mechanics the vertical effective stress 1205901015840 forexample is typically calculated by
1205901015840
= 120590119905
minus 119906 (4)
where 120590119905 and 119906 are total stress and pore pressure respectivelyFor a uniform layer with no pore pressure the total verticalstress at a depth119867may be calculated by
120590119905
= 120588119892119867 (5)
where 120588 represents the density of the layer and 119892 representsgravity In the conventional form of centrifugemodeling [26]it is typical that the same materials are used in the model andprototype therefore the densities are the same in model andprototype that is
120588lowast
= 1 (6)
Furthermore in conventional centrifugemodeling all lengthsare scaled by the same factor 119871lowast To produce the same stressin the model as in the prototype we thus require
120588lowast
119892lowast
119867lowast
= 1119892lowast
119871lowast
= 1 (7)
It may be rewritten as
119892lowast
=1
119871lowast
(8)
The above scaling law states that if lengths in the model arereduced by some factor 119899 then gravitational accelerationsmust be increased by the same factor 119899 in order to preserveequal stresses in model and prototype
Shock and Vibration 9
1650
950
500 5200 500
1000
1000785
Laterite
Water
Sand
(a)
1650
950
500 5200 500
1000
1000785
Laterite
Water
Sand
(b)
1650
950
500 5200 500
1000
1000785
Laterite
Water
Sand
(c)
1650
950
500 5200 500
1000
1000785 Water
Sand
Laterite reinforced
(d)
1650
950
1000
1000785
Laterite
Water
Sand
500 5200 500
(e)
Figure 17 Model introducing ((a) (b) (c) (d) and (e)) for small dam (cm) (119878 = 1100)
For dynamic problems where gravity and accelerationsare important all accelerations must scale as gravity is scaledthat is
119886lowast
= 119892lowast
=1
119871lowast
(9)
Since acceleration has units of 1198711198792 it is required that
119886lowast
=119871lowast
1198792
(10)
Hence it is required that
1
119871lowast
=119871lowast
1198792
or 119879lowast
= 119871lowast
(11)
Frequency has units of inverse of time and velocity has unitsof length per time so for dynamic problems we also obtain
119891lowast
=1
119871lowast
Vlowast =119871lowast
119879lowast
= 1 (12)
For model tests involving dynamics the conflict in time scalefactors may be resolved by scaling the permeability of the soil[26]
35 Free Vibration Analysis In dynamic assessment freevibration analysis is the base of study In fact the distributionof frequency in the different vibrationmode can be computedby the application of modal analysis based on finite-elementmethod (FEM) It is worth mentioning that this analysis isperfectly related to the mass and spring In case of the mass-spring-damper system the first assumption is negligibleabout damping effect Therefore there is not any externalforce on mass in this state The force applied to the massby the spring is proportional to the amount of the springthat is stretched ldquo119909rdquo (it can be assumed that spring isalready compressed due to the weight of the mass) Theproportionality constant (119896) is spring stiffness (see Figure 14)The unit measurement is force divided by distance (kgm)
10 Shock and Vibration
(a) (b)
(c) (d)
Figure 18 Small scale dam (a) Dam perspective with two LVDT (b) soil compaction with roller (c) dam section with index network and(d) dam with tank before vibration
The negative sign indicates that force is always opposingthe motion of the mass attached to it according to thefollowing equation
119865119904
= minus119896119909 (13)
The force generated by the mass is proportional to theacceleration of the mass as given by Newtonrsquos second law ofmotion
sum119865 = 119898119886 = 119898 = 1198981198892
119909
1198891199052
(14)
The sumof the forces on themass then generates this ordinarydifferential equation
119898 + 119896119909 = 0 (15)
Assuming that the initial vibration can be started by stretch-ing and releasing the spring with distance (119860) the solution tothe above equation that describes the motion of mass can beseen in the following equation
119909 (119905) = 119860 cos (2120587119891119899
119905) (16)
This solution shows that it will oscillate with simple harmonicmotion that has amplitude of (119860) and a frequency (119891
119899
) Thenumber (119891
119899
) is called the undamped natural frequency Forthe simple mass-spring system frequency is given by
119891119899
=1
2120587
radic119896
119898 (17)
However the relation between frequency and vibrationperiod is always reverse Consider
119879 =1
119891 (18)
In terms of the measurement unit the vibration periodand frequency were according to seconds and hertz It isworth noting that the dominant frequency is the minimumfrequency to produce maximum vibration period
4 Numerical Analysis
In terms of numerical analysismodal analysis was carried outby using ANSYS program in this study to compute dominantfrequency for small scale model regarding 3D analysis Thisprogram is one of the famous software programs with respectto finite-elementmethod (FEM) In particular this software isone of the universal programs with high level of the ability fordifferent analyses A strong ability to compute free vibrationanalysis is possible with modal analysis [27]
41 Elements and Meshing Process To select element basedon Help menu solid 8 nodes 183 (3D) were used for thispurpose Figure 15 shows the mapped mesh for numericalmodeling In this figure 23956 elements and 35457 nodes inmodels were used for free vibration analysis According tothis condition free vibration analysis to access frequency indifferent vibration modes was carried out as results can bediscussed in the next section
Shock and Vibration 11
0 20 40 60 80 100 1200
minus01
minus02
minus03
minus04
minus05
minus06
62 minus029
90 minus048
Time (s)
Disp
lace
men
t (m
m)
Time (s)0 10 20 30 40 50 60 70 80 90 100 110 120
03
025
02
015
01
005
0
Rela
tive
disp
lace
men
t (m
m)
96 024
Model A
0 20 40 60 80 100 120
Time (s)
Disp
lace
men
t (m
m) 2
15
1
05
0
minus05
minus1
minus15
84 15
104 minus064
Time (s)0 10 20 30 40 50 60 70 80 90 100 110 120
Rela
tive
disp
lace
men
t (m
m) 25
2
15
1
05
0
minus05
minus1
104 213
Model B
0 20 40 60 80 100 120
Time (s)
Disp
lace
men
t (m
m)
01201008006004002
0minus002minus004
108 01
108 006
Time (s)
0 10 20 30 40 50 60 70 80 90 100 110 120
Rela
tive
disp
lace
men
t (m
m)
007
006
005
004
003
002
001
0
8 006
Model C
Time (s)0 10 20 30 40 50 60 70 80 90 100 110 120
Rela
tive
disp
lace
men
t (m
m)
0201501005
0minus005minus01minus015minus02
90 017
26 minus017
0 20 40 60 80 100 120
Time (s)
Disp
lace
men
t (m
m) 015
01005
0
minus01minus015
minus005
minus02minus025
114 minus007116 minus022
Model DTime (s)
Disp
lace
men
t (m
m)
01
0
minus01
minus02
minus03
minus04
104 minus011
102 minus033
0 20 40 60 80 100 120
Up streamDown stream
Time (s)
0 10 20 30 40 50 60 70 80 90 100 110 120
Rela
tive
disp
lace
men
t (m
m)
03
025
02
015
01
0
005
86 025
Model E
Figure 19 Vertical displacement in both edges of the crest in models with relative displacement
12 Shock and Vibration
(a) (b) (c)
Figure 20 Damage in the first model (Model A)
(a) (b)
(c) (d)
Figure 21 Damage in the second model (Model B)
42 Free Vibration Analysis and Dominant Frequency Interms of modal analysis the free vibration analysis was cal-culated by ANSYS program Figure 16 shows displacement inthree directions of model and total displacement in the firstvibration mode because based on distribution of frequencyin the first mode to fifth mode it is important to note thatthe minimum frequency (022986Hz) was observed in thefirst vibration mode It means that the vibration period wasmaximum and critical in this mode
Distribution of frequency in different vibration modesindicated that this value was respectively obtained at026257Hz 028387Hz and 030135Hz in the vibration shapemodes 2 to 4
5 Results and Discussion Based on PhysicalSmall Scale Modeling
In order to find the best location of reinforcement in damfive small dams with different locations of reinforcementusing IDL material were vibrated by dominant frequency
(22986Hz) with respect to resonance condition Figure 17shows five small scale dams (Models (a) (b) (c) and (d))it is obvious that models have the same dimension In thisfigure the reinforced area was illustrated with a hatch areaFor example Model (d) indicated that all dam body wasreinforced For this purpose one steel box for modeling wasused This box made by five sheets of Plexiglas with 20mmthickness One of them was in the base of model The levelof reservoir was 75 of the dam height The scale parameterwas 1100 Itmeans thatmodel was one hundred times smallerthan prototypeThedamheightwas 227meter in reality but itwas made 227 cm in physical model In addition small scalemodeling was coupled by foundation Foundation materialwas dense sand with 75 relative density Sand propertieswere mentioned in soil mechanic test Figure 18 shows somedetails including dam perspective soil compaction networkindex and reservoir In this Figure two LVDT on the middleof model at the both edges of the crest were installed Inorder to achieve support one steel frame and one steel beamwere applied (see Figure 18(a)) However both LVDT wereconnected to data logger device by specific cables In terms
Shock and Vibration 13
(a) (b)
Figure 22 Damage in the third model (Model C)
of compaction soil for each layer the steel roller used wasselected by trial error methodWoodmolding with respect tocontrol slope via network index was used In order to avoidabsorption of soil water content both the described moldswere just soaked by water before use For tank purpose smallscale models were filled up by water with very slow rate
After vibration equal to two minutes for all modelsthe vertical displacement for both slopes such as upstreamand downstream were printed With respect to use of Excelprogram Figure 19 shows the distribution of vertical displace-ment in both edges in the middle of the crest and relativedisplacement in all models It was obvious that distributionof the vertical displacement indicated a same trend for bothmodels such as A and E In both models displacement valueswere negative during the vibration It means that both ofthem were in uplift condition In this figure also maximumandminimum peak of the relative displacement respectivelyoccurred in Models B and C with 213mm and 006mm It isalso worth noting that this value was at convergence positionfor Models A and E with 024mm and 025mm respectively
In terms of damage location in models Figure 20 showsthe damage in Model A which occurred at upstream anddownstream The level of damage was greater in upstream Itwas very sensible occurrence in case of hydrodynamic pres-sure along the vibration Also in this figure the maximumlongitudes cracks (see line C) were observed near to themiddle of dam at the crest For damage at downstream thetransverse cracks significantly occurred in dam toe
Figure 21 shows Model B that was damaged after vibra-tion It can be observed that dam was significantly damagedin some locations such as crest and surfaces Body cracks andfailure process dramatically occurred in both areas near toabutments Also in this figure one transverse crack in themiddle of the crest was seen (see Figure 20(c)) This damagewas significantly repeated at upstream in Model C but itwas placed in dam toe and it can be seen in Figure 22 Inaddition Model D was damaged in three places such as bothabutments and the middle of the upstream Figure 23 showsModel D that was damaged in toe Briefly all four modelswere damaged as discussed previously On the other handa successful way in order to remove damage was obtained inModel E as shown in Figure 24 Figure 24 shows that model
Figure 23 Damage in the fourth model (Model D)
was safe after vibration without any damage In this figurethe reinforced blanket layer using IDLmaterial was indicatedby red circles between dam and foundation In addition itwas very important to note that both surfaces were safe anddam was stable under severe seismic loading like resonancemotion In fact a good absorption of energy with respectto increase of damping was found by using IDL In case ofusing this technique displacement in both edges of the crestwith negative value indicated the uplift situation Moreoverrelative displacement was like the first model Thereforedam behavior before and after reinforcement was similar forboth distributions of displacement Nevertheless Model Ewas successful to remove damage with respect to high levelof damping in blanket layer In fact this model shows theexcellent performance in earth dams when the blanket layerwas expanded below tank
Finally blanket layer using isolator damper layer (IDL)below dam and tank is a good recommendation for earthdams in seismic zonewhen reinforced thickness is one-fourthof damheight As recommended optimization of thickness inthis method is the next study
6 Conclusion
In this study the earth dam performance under severeseismic motion such as resonance was evaluated by usingblanket layer (IDL) With respect to soil mechanic testthe optimum mixture for IDL was designed IDL powderwas made by using some materials Main material was alocal soil (laterite) with 90 and additives such as TDA
14 Shock and Vibration
(a) (b)
(c) (d)
Figure 24 Dam stabilization in the fifth model (Model E)
(tire derived aggregate with 7) and MS (microsilica) with3 were used This material was utilized to reinforce damin small scale physical modeling According to numericalanalysis the dominant frequency (02298Hz) in order tohave maximum effect for modeling vibration was computedBy using this frequency for physical modeling the damagelocation and distribution of vertical displacement at bothedges of the crest in the middle of small dams for five smallmodel with scale 1100 were discussed As results the bestperformance in order to remove damages was obviouslyobserved in Model E while other models were dramaticallydamaged in some locations such as upstream downstreamand crest In addition the thickness of blanket layer in thismodel was one-fourth of dam height Finally this model is anovel method to reinforce dam under strong earthquake likeresonance phenomena recommended for earth dam designin seismic zone
Conflict of Interests
The authors declare that there is no conflict of interestsregarding the publication of this paper
Acknowledgment
This study ismade possible by the support of the InternationalDoctorate Fellowship of Universiti Teknologi Malaysia andit is very much appreciated
References
[1] M Zeghal and A M Abdel-Ghaffar ldquoAnalysis of behavior ofearth dam using strong-motion earthquakes recordsrdquo Journalof Geotechnical Engineering vol 118 no 2 pp 266ndash277 1992
[2] V Gikas andM Sakellariou ldquoSettlement analysis of theMornosearth dam (Greece) evidence from numerical modeling andgeodetic monitoringrdquo Engineering Structures vol 30 no 11 pp3074ndash3081 2008
[3] R Verdugo N Sitar J D Frost et al ldquoSeismic performanceof earth structures during the February 2010 Maule Chileearthquake dams levees tailings dams and retaining wallsrdquoEarthquake Spectra vol 28 no 1 pp S75ndashS96 2012
[4] Y Parish and F N Abadi ldquoDynamic behaviour of earth damsfor variation of earth material stiffnessrdquo Proceedings of WorldAcademy of Science Engineering and Technology vol 50 pp606ndash611 2009
[5] T G Berhe X T Wang and W Wu ldquoNumerical investigationinto the arrangement of clay core on the seismic performanceof earth damsrdquo in Proceedings of the GeoShanghai InternationalConference on Soil Dynamics and Earthquake Engineering pp131ndash138 ASCE June 2010
[6] Z F Xia G L Ye J HWang B Ye and F Zhang ldquoFully couplednumerical analysis of repeated shake-consolidation process ofearth embankment on liquefiable foundationrdquo Soil Dynamicsand Earthquake Engineering vol 30 no 11 pp 1309ndash1318 2010
[7] X J Kong Y Zhou B Xu and D G Zou ldquoAnalysis on seismicfailure mechanism of Zipingpu dam and several reflections ofaseismic design for high rock-fill damrdquo in Proceedings of theEarth and Space pp 3177ndash3189 March 2010
Shock and Vibration 15
[8] A BayraktarM E Kartal and S Adanur ldquoThe effect of concreteslabrockfill interface behavior on the earthquake performanceof a CFR damrdquo International Journal of Non-Linear Mechanicsvol 46 no 1 pp 35ndash46 2011
[9] R P Piao A H Rippe B Myers and K W Lane ldquoEarthdam liquefaction and deformation analysis using numericalmodelingrdquo in Proceedings of the GeoCongress pp 1ndash6 March2006
[10] A W Elgamal ldquoThree-dimensional seismic analysis of la villitadamrdquo Journal of Geotechnical Engineering vol 118 no 12 pp1937ndash1958 1992
[11] B Gordan and B A Azlan ldquoEffect of material properties inCFRD tailing-embankment bridge during a strong earthquakerdquoCaspian Journal of Applied Sciences Research vol 2 no 11 pp61ndash72 2013
[12] A Papalou and J Bielak ldquoSeismic elastic response of Earthdams with canyon interactionrdquo Journal of Geotechnical andGeoenvironmental Engineering vol 127 no 5 pp 446ndash453 2001
[13] Y Yu L Xie and B Zhang ldquoStability of earth-rockfill damsinfluence of geometry on the three-dimensional effectrdquo Com-puters and Geotechnics vol 32 no 5 pp 326ndash339 2005
[14] L H Mejia and H B Seed ldquoComparison of 2-D and 3-D dynamic analyses of earth damsrdquo Journal of GeotechnicalEngineering vol 109 no 11 pp 1383ndash1398 1983
[15] J L Borges ldquoThree-dimensional analysis of embankmentson soft soils incorporating vertical drains by finite elementmethodrdquoComputers andGeotechnics vol 31 no 8 pp 665ndash6762004
[16] A Yildiz ldquoNumerical analyses of embankments on PVDimproved soft claysrdquo Advances in Engineering Software vol 40no 10 pp 1047ndash1055 2009
[17] B Le Hello and P Villard ldquoEmbankments reinforced by pilesand geosynthetics-Numerical and experimental studies dealingwith the transfer of load on the soil embankmentrdquo EngineeringGeology vol 106 no 1-2 pp 78ndash91 2009
[18] S W Abusharar J J Zheng B G Chen and J H Yin ldquoA sim-plified method for analysis of a piled embankment reinforcedwith geosyntheticsrdquo Geotextiles and Geomembranes vol 27 no1 pp 39ndash52 2009
[19] R Noorzad and M Omidvar ldquoSeismic displacement analysisof embankment dams with reinforced cohesive shellrdquo SoilDynamics and Earthquake Engineering vol 30 no 11 pp 1149ndash1157 2010
[20] T Matsumaru K Watanabe and J Isono ldquoApplication ofcement-mixed gravel reinforced by ground for soft groundimprovementrdquo in Proceedings of the 4th Asian Regional Confer-ence on Geosynthetics pp 380ndash385 Shanghai China June 2008
[21] Namdar and A A K Pelko ldquoSeismic evaluation of embank-ment shaking table test and finite element methodrdquo ThePacific Journal of Science and Technology vol 11 no 2 2010httpwwwakamaiuniversityusPJST
[22] L Wang G Zhang and J Zhang ldquoCentrifuge model tests ofgeotextile-reinforced soil embankments during an earthquakerdquoGeotextiles and Geomembranes vol 29 no 3 pp 222ndash232 2011
[23] H B Seed R T Wong I M Idriss and K Tokimatsu ldquoModuliand damping factors for dynamic analyses of cohesionless soilsrdquoJournal of Geotechnical Engineering vol 112 no 11 pp 1016ndash1032 1986
[24] B M Das Advanced Soil Mechanics CRC Press New York NYUSA 2013
[25] M J Griffin Handbook of Human Vibration Academic PressNew York NY USA 2012
[26] J Garnier C Gaudin S M Springman P J Culligan DJ Goodings and D Konig ldquoCatalogue of scaling laws andsimilitude questions in geotechnical centrifuge modellingrdquoInternational Journal of Physical Modelling in Geotechnics vol7 no 3 pp 1ndash23 2007
[27] A Fluent 120 Userrsquos Guide User Inputs for PorousMedia 2009
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Shock and Vibration
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DistributedSensor Networks
International Journal of
Shock and Vibration 5
01055
0093301137
0117701566
0207
0111201163
00675
01533 01544
00625
0081
0
005
01
015
02
025
Sam
ple 1
Sam
ple 2
Sam
ple 3
Sam
ple 4
Sam
ple 5
Sam
ple 6
Sam
ple 7
Sam
ple 8
Sam
ple 9
Sam
ple 1
0
Sam
ple 1
1
Sam
ple 1
2
Sam
ple 1
3
mv (average)
(m2M
N)
(a) Coefficient of volume compressibility
Sam
ple 1
Sam
ple 2
Sam
ple 3
Sam
ple 4
Sam
ple 5
Sam
ple 6
Sam
ple 7
Sam
ple 8
Sam
ple 9
Sam
ple 1
0
Sam
ple 1
1
Sam
ple 1
2
Sam
ple 1
3
4416
3395
36076
31893463
8159
3118
28552487
11922659
1596
2311
0102030405060708090
cv (average)
(m2y
ear)
(b) Coefficient of consolidation
Figure 7 Distribution of coefficients in samples for consolidation test (a) Coefficient of volume compressibility and (b) coefficient ofconsolidation
Sam
ple 1
Sam
ple 2
Sam
ple 3
Sam
ple 4
Sam
ple 5
Sam
ple 6
Sam
ple 7
Sam
ple 8
Sam
ple 9
Sam
ple 1
0
Sam
ple 1
1
Sam
ple 1
2
Sam
ple 1
3Permeability (cms)
000E + 00
500E minus 05
100E minus 04
150E minus 04
200E minus 04
250E minus 04
300E minus 04
129E minus 05345E minus 05
613E minus 05
710E minus 05
242E minus 04
386E minus 05
450E minus 05
257E minus 05
322E minus 05
167E minus 05
206E minus 05
234E minus 04
213E minus 04
Figure 8 Distribution of permeability for different samples
Table 4 Sand properties
Physical properties ValueSpecific gravity 2547Cohesion (KPa) 000Angle of internal friction (Degree) 35Modulus elasticity (KPa) 32460Maximum dry density (grcm3) 172Minimum dry density (grcm3) 136Density for 119868
119889
= 75 (grcm3) 1613Permeability (cms) 01Maximum size (mm) 200Minimum size (mm) 0075Uniformity coefficient 119862
119906
4375Coefficient of curvature 119862
119888
097
3 Small Scale Model on Vibrator Table
Physical models with scale parameter equal to 1100 weretested In order to research methodology for this purposesome aspects included characteristic of vibrator table dis-placement transducer data logger sinusoidal motion scaleparameter for static or dynamic condition free vibrationanalysis and physical modeling will be presented In this
study five small scale dams were tested as will be explainedin the next section
31 Vibrator Table In this study vibrating table 24-9112(CN-166) with respect to sinus motion was used Figure 11shows the vibrating desk that was cushioned with steeland seminoiseless electromagnetic vibrator with 3600 vpmoperating frequency In addition it has a separate controllerto vary vibrator amplitude in case of frequency capacitylimit 100Hz Table capacity was equal to 750 lbs (340 kg)Double amplitude range was located at 0002 inch (005mm)to 0015 inch (038mm) Actuator was an electromagneticvibrator over 100 lbs (4530 kg)The table was square in shapeand 30 inch (762mm) The table thickness was 333mm ofsteel In case of weight it was net 555 lbs (252 kg) and shippingwas 605 lbs (274 kg) Figure 11 illustrates the vibrator table forthis study
32 Displacement Transducerand Data Logger Displacementtransducer CDP-D was utilized with respect to dual isolatedIO ports By using transducer one set of cables for input andoutput was connected to the analog measuring instrumentand another set to the digital measuring instrument Withtwo different types of measuring equipment connected tothis transducer simultaneous measurements can be madewithout interference Figure 12(a) shows the displacementtransducer and Figure 12(b) shows the dimensions for trans-ducer CDP-100 Tomeasure displacement at both edges of thecrest in small scale modeling two transducers were installedIn terms of data record data logger or data recorder is anelectronic device that records data over time or in relation tolocation with either a built in instrument or a sensor or viaexternal instruments and sensors
Figure 12(c) illustrates the data logger that was used inthis study Based on device ability results were printed duringthe vibration duration After that results were classified byusing Excel program It should be noted that both transducersas mentioned previously were connected to this data logger(UCAM-70A) in order to record vertical displacement duringthe vibration In addition the sub step of vibration periodwas
6 Shock and Vibration
Stress
Strain
(a)
Stress
Strain
(b)
Figure 9 Damping definition and hysteretic and equivalent bilinear stress-strain relationships for soil (a) stress-strain curves (b) bilinearidealization [23]
400
300
200
100
0
minus100
minus200
minus300
minus400
minus003 minus002 minus001 0 001 002 003
0020
00168
00225Stress (kPa)
Strain
Blue area = 377
Loop area = 850
Damping = 01795
Hysteresis loop-sample 1
(a)
250200150100500
minus50minus100minus150minus200minus250
minus006 minus004 minus002 0 002 004 006
00425
0034
00404
Stress (kPa)
Strain
Hysteresis loop-sample 10
Blue area = 421Loop area = 1197
Damping = 02263
(b)
Figure 10 Estimation of damping ratio (a) sample 1 and (b) sample 10
Figure 11 Vibrator table
equal to two seconds based on device ability with respect toprint
33 Sinusoidal Vibrate Loading There is a mathematicalrelationship between frequency displacement velocity andacceleration for sinusoidalmotion according to considerationof the peak value for them The relationship is such that ifany two of the four variables are known the other two can becalculated Table 5 shows all equations that were provided inthis context [25]
Table 5 Conversion for peak value in sinusoidal motion displace-ment (X) velocity (V) acceleration (A) and frequency (f )
Displacement X Velocity V Acceleration A
Displacement X 119883 = 119883 119883 =119881
2120587119891119883 =
119860
(2120587119891)2
Velocity V 119881 = 2120587119891119883 119881 = 119881 119881 =119860
2120587119891
Acceleration A 119860 = (2120587119891)2
119883 119860 = 2120587119891119881 119860 = 119860
119866 in these formulas is not gravity acceleration It is aconstant for calculation within different systems Respec-tively for metric imperial and Si 119866 is 980665ms23860885827 ins2 and 100ms2
Since themotion is sinusoidal the displacement velocityand acceleration are changing sinusoidal trend Howeverthey are not in the same phase The phase relationshipbetween displacement velocity and acceleration is that veloc-ity is 90∘ out of phase with acceleration and displacement is180∘ out of phase with acceleration
Shock and Vibration 7
(a)
CDP-D
12060110120601D
10
120601E
C A
120601BInputoutput 1Inputoutput 2
2 inputoutput cables
Dimensions
TypeCDP-50-D
A B C D E
165 335 65 5 10
(b)
(c)
Figure 12 Transducer and data logger (a) Displacement transducer CDP-100 (b) dimension of displacement transducer (CDP-100) and (c)data logger UCAM-70A
155
minus5minus15
20100
minus10minus20
25155
minus5minus15minus25
Displacement 13mm peak
Velocity 16336ms peak
Acceleration 2090gn peak
Figure 13 20Hz sinusoidal motion
In other words when displacement is at a maximumvelocity is at a minimum and acceleration is at a maximumIt should be noted that 1 119892
119899
= 980665ms2 = 32174 fts2 =3860886 ins2 Figure 13 shows the example of displacementdistribution with velocity and acceleration while the fre-quency of sinusoidal motion is twenty hertz
34 Scaling Laws In case of the scale parameter the scalefactor can be used according to
119909lowast
=119909119898
119909119901
(2)
The subscript 119898 represents ldquomodelrdquo and the subscript 119901represents ldquoprototyperdquo and 119909lowast represents the scale factor forthe quantity 119909 [26]
k
mx
Figure 14 Mass spring system
Figure 15 Free mesh
The reason for spinning a model on a centrifuge is toenable small scale models to feel the same effective stresses asa full scale prototype This goal can be stated mathematicallyas
1205901015840119909
=1205901015840
119898
1205901015840
119901
= 1 (3)
where the asterisk represents the scaling factor for thequantity 1205901015840
119898
is the effective stress in the model and 1205901015840119901
is theeffective stress in the prototype
8 Shock and Vibration
Nodal solutionStep = 1
UX (Avg)RSYS = 0
DMX = 0288E minus 03
SMX = 0271E minus 04
Sub = 1X
Y
Z
MN
MX
minus0271E
minus04
minus0210E
minus04
minus0150E
minus04
minus0902Eminus05
minus0301Eminus05
0301Eminus05
0902Eminus05
0150E
minus04
0210E
minus04
0271E
minus04
SMN = minus0271E minus 04
Freq = 0229855
(a)
Nodal solutionStep = 1
Sub = 1
UY (Avg)RSYS = 0
DMX = 0288E minus 03
SMX = 0126E minus 03
X
Y
Z
MN
MX
minus0971E
minus04
minus0125E
minus03
minus0692E
minus04
minus0413Eminus04
minus0134Eminus04
0145Eminus04
0423E
minus04
0702E
minus04
0981E
minus04
0126E
minus03
SMN = minus0125E minus 03
Freq = 0229855
(b)
X
Y
Z MN
MX
0
0287E
minus04
0575E
minus04
0862Eminus04
0115Eminus03
0144Eminus03
0172Eminus03
0201E
minus03
0230E
minus03
0259E
minus03
Nodal solutionStep = 1
UZ (Avg)RSYS = 0
DMX = 0288E minus 03
SMX = 0259E minus 03
Sub = 1
Freq = 0229855
(c)
X
Y
Z
MX0
0320E
minus04
0639E
minus04
0959Eminus04
0128Eminus03
0160Eminus03
0192Eminus03
0224E
minus03
0256E
minus03
0288E
minus03
Nodal solutionStep = 1
Sub = 1
USUM (Avg)RSYS = 0
DMX = 0288E minus 03
SMX = 0288E minus 03
MN
Freq = 0229855
(d)
Figure 16 Mode shape 1 (a) horizontal displacement (b) vertical displacement (c) lateral displacement and (d) total displacement
In soil mechanics the vertical effective stress 1205901015840 forexample is typically calculated by
1205901015840
= 120590119905
minus 119906 (4)
where 120590119905 and 119906 are total stress and pore pressure respectivelyFor a uniform layer with no pore pressure the total verticalstress at a depth119867may be calculated by
120590119905
= 120588119892119867 (5)
where 120588 represents the density of the layer and 119892 representsgravity In the conventional form of centrifugemodeling [26]it is typical that the same materials are used in the model andprototype therefore the densities are the same in model andprototype that is
120588lowast
= 1 (6)
Furthermore in conventional centrifugemodeling all lengthsare scaled by the same factor 119871lowast To produce the same stressin the model as in the prototype we thus require
120588lowast
119892lowast
119867lowast
= 1119892lowast
119871lowast
= 1 (7)
It may be rewritten as
119892lowast
=1
119871lowast
(8)
The above scaling law states that if lengths in the model arereduced by some factor 119899 then gravitational accelerationsmust be increased by the same factor 119899 in order to preserveequal stresses in model and prototype
Shock and Vibration 9
1650
950
500 5200 500
1000
1000785
Laterite
Water
Sand
(a)
1650
950
500 5200 500
1000
1000785
Laterite
Water
Sand
(b)
1650
950
500 5200 500
1000
1000785
Laterite
Water
Sand
(c)
1650
950
500 5200 500
1000
1000785 Water
Sand
Laterite reinforced
(d)
1650
950
1000
1000785
Laterite
Water
Sand
500 5200 500
(e)
Figure 17 Model introducing ((a) (b) (c) (d) and (e)) for small dam (cm) (119878 = 1100)
For dynamic problems where gravity and accelerationsare important all accelerations must scale as gravity is scaledthat is
119886lowast
= 119892lowast
=1
119871lowast
(9)
Since acceleration has units of 1198711198792 it is required that
119886lowast
=119871lowast
1198792
(10)
Hence it is required that
1
119871lowast
=119871lowast
1198792
or 119879lowast
= 119871lowast
(11)
Frequency has units of inverse of time and velocity has unitsof length per time so for dynamic problems we also obtain
119891lowast
=1
119871lowast
Vlowast =119871lowast
119879lowast
= 1 (12)
For model tests involving dynamics the conflict in time scalefactors may be resolved by scaling the permeability of the soil[26]
35 Free Vibration Analysis In dynamic assessment freevibration analysis is the base of study In fact the distributionof frequency in the different vibrationmode can be computedby the application of modal analysis based on finite-elementmethod (FEM) It is worth mentioning that this analysis isperfectly related to the mass and spring In case of the mass-spring-damper system the first assumption is negligibleabout damping effect Therefore there is not any externalforce on mass in this state The force applied to the massby the spring is proportional to the amount of the springthat is stretched ldquo119909rdquo (it can be assumed that spring isalready compressed due to the weight of the mass) Theproportionality constant (119896) is spring stiffness (see Figure 14)The unit measurement is force divided by distance (kgm)
10 Shock and Vibration
(a) (b)
(c) (d)
Figure 18 Small scale dam (a) Dam perspective with two LVDT (b) soil compaction with roller (c) dam section with index network and(d) dam with tank before vibration
The negative sign indicates that force is always opposingthe motion of the mass attached to it according to thefollowing equation
119865119904
= minus119896119909 (13)
The force generated by the mass is proportional to theacceleration of the mass as given by Newtonrsquos second law ofmotion
sum119865 = 119898119886 = 119898 = 1198981198892
119909
1198891199052
(14)
The sumof the forces on themass then generates this ordinarydifferential equation
119898 + 119896119909 = 0 (15)
Assuming that the initial vibration can be started by stretch-ing and releasing the spring with distance (119860) the solution tothe above equation that describes the motion of mass can beseen in the following equation
119909 (119905) = 119860 cos (2120587119891119899
119905) (16)
This solution shows that it will oscillate with simple harmonicmotion that has amplitude of (119860) and a frequency (119891
119899
) Thenumber (119891
119899
) is called the undamped natural frequency Forthe simple mass-spring system frequency is given by
119891119899
=1
2120587
radic119896
119898 (17)
However the relation between frequency and vibrationperiod is always reverse Consider
119879 =1
119891 (18)
In terms of the measurement unit the vibration periodand frequency were according to seconds and hertz It isworth noting that the dominant frequency is the minimumfrequency to produce maximum vibration period
4 Numerical Analysis
In terms of numerical analysismodal analysis was carried outby using ANSYS program in this study to compute dominantfrequency for small scale model regarding 3D analysis Thisprogram is one of the famous software programs with respectto finite-elementmethod (FEM) In particular this software isone of the universal programs with high level of the ability fordifferent analyses A strong ability to compute free vibrationanalysis is possible with modal analysis [27]
41 Elements and Meshing Process To select element basedon Help menu solid 8 nodes 183 (3D) were used for thispurpose Figure 15 shows the mapped mesh for numericalmodeling In this figure 23956 elements and 35457 nodes inmodels were used for free vibration analysis According tothis condition free vibration analysis to access frequency indifferent vibration modes was carried out as results can bediscussed in the next section
Shock and Vibration 11
0 20 40 60 80 100 1200
minus01
minus02
minus03
minus04
minus05
minus06
62 minus029
90 minus048
Time (s)
Disp
lace
men
t (m
m)
Time (s)0 10 20 30 40 50 60 70 80 90 100 110 120
03
025
02
015
01
005
0
Rela
tive
disp
lace
men
t (m
m)
96 024
Model A
0 20 40 60 80 100 120
Time (s)
Disp
lace
men
t (m
m) 2
15
1
05
0
minus05
minus1
minus15
84 15
104 minus064
Time (s)0 10 20 30 40 50 60 70 80 90 100 110 120
Rela
tive
disp
lace
men
t (m
m) 25
2
15
1
05
0
minus05
minus1
104 213
Model B
0 20 40 60 80 100 120
Time (s)
Disp
lace
men
t (m
m)
01201008006004002
0minus002minus004
108 01
108 006
Time (s)
0 10 20 30 40 50 60 70 80 90 100 110 120
Rela
tive
disp
lace
men
t (m
m)
007
006
005
004
003
002
001
0
8 006
Model C
Time (s)0 10 20 30 40 50 60 70 80 90 100 110 120
Rela
tive
disp
lace
men
t (m
m)
0201501005
0minus005minus01minus015minus02
90 017
26 minus017
0 20 40 60 80 100 120
Time (s)
Disp
lace
men
t (m
m) 015
01005
0
minus01minus015
minus005
minus02minus025
114 minus007116 minus022
Model DTime (s)
Disp
lace
men
t (m
m)
01
0
minus01
minus02
minus03
minus04
104 minus011
102 minus033
0 20 40 60 80 100 120
Up streamDown stream
Time (s)
0 10 20 30 40 50 60 70 80 90 100 110 120
Rela
tive
disp
lace
men
t (m
m)
03
025
02
015
01
0
005
86 025
Model E
Figure 19 Vertical displacement in both edges of the crest in models with relative displacement
12 Shock and Vibration
(a) (b) (c)
Figure 20 Damage in the first model (Model A)
(a) (b)
(c) (d)
Figure 21 Damage in the second model (Model B)
42 Free Vibration Analysis and Dominant Frequency Interms of modal analysis the free vibration analysis was cal-culated by ANSYS program Figure 16 shows displacement inthree directions of model and total displacement in the firstvibration mode because based on distribution of frequencyin the first mode to fifth mode it is important to note thatthe minimum frequency (022986Hz) was observed in thefirst vibration mode It means that the vibration period wasmaximum and critical in this mode
Distribution of frequency in different vibration modesindicated that this value was respectively obtained at026257Hz 028387Hz and 030135Hz in the vibration shapemodes 2 to 4
5 Results and Discussion Based on PhysicalSmall Scale Modeling
In order to find the best location of reinforcement in damfive small dams with different locations of reinforcementusing IDL material were vibrated by dominant frequency
(22986Hz) with respect to resonance condition Figure 17shows five small scale dams (Models (a) (b) (c) and (d))it is obvious that models have the same dimension In thisfigure the reinforced area was illustrated with a hatch areaFor example Model (d) indicated that all dam body wasreinforced For this purpose one steel box for modeling wasused This box made by five sheets of Plexiglas with 20mmthickness One of them was in the base of model The levelof reservoir was 75 of the dam height The scale parameterwas 1100 Itmeans thatmodel was one hundred times smallerthan prototypeThedamheightwas 227meter in reality but itwas made 227 cm in physical model In addition small scalemodeling was coupled by foundation Foundation materialwas dense sand with 75 relative density Sand propertieswere mentioned in soil mechanic test Figure 18 shows somedetails including dam perspective soil compaction networkindex and reservoir In this Figure two LVDT on the middleof model at the both edges of the crest were installed Inorder to achieve support one steel frame and one steel beamwere applied (see Figure 18(a)) However both LVDT wereconnected to data logger device by specific cables In terms
Shock and Vibration 13
(a) (b)
Figure 22 Damage in the third model (Model C)
of compaction soil for each layer the steel roller used wasselected by trial error methodWoodmolding with respect tocontrol slope via network index was used In order to avoidabsorption of soil water content both the described moldswere just soaked by water before use For tank purpose smallscale models were filled up by water with very slow rate
After vibration equal to two minutes for all modelsthe vertical displacement for both slopes such as upstreamand downstream were printed With respect to use of Excelprogram Figure 19 shows the distribution of vertical displace-ment in both edges in the middle of the crest and relativedisplacement in all models It was obvious that distributionof the vertical displacement indicated a same trend for bothmodels such as A and E In both models displacement valueswere negative during the vibration It means that both ofthem were in uplift condition In this figure also maximumandminimum peak of the relative displacement respectivelyoccurred in Models B and C with 213mm and 006mm It isalso worth noting that this value was at convergence positionfor Models A and E with 024mm and 025mm respectively
In terms of damage location in models Figure 20 showsthe damage in Model A which occurred at upstream anddownstream The level of damage was greater in upstream Itwas very sensible occurrence in case of hydrodynamic pres-sure along the vibration Also in this figure the maximumlongitudes cracks (see line C) were observed near to themiddle of dam at the crest For damage at downstream thetransverse cracks significantly occurred in dam toe
Figure 21 shows Model B that was damaged after vibra-tion It can be observed that dam was significantly damagedin some locations such as crest and surfaces Body cracks andfailure process dramatically occurred in both areas near toabutments Also in this figure one transverse crack in themiddle of the crest was seen (see Figure 20(c)) This damagewas significantly repeated at upstream in Model C but itwas placed in dam toe and it can be seen in Figure 22 Inaddition Model D was damaged in three places such as bothabutments and the middle of the upstream Figure 23 showsModel D that was damaged in toe Briefly all four modelswere damaged as discussed previously On the other handa successful way in order to remove damage was obtained inModel E as shown in Figure 24 Figure 24 shows that model
Figure 23 Damage in the fourth model (Model D)
was safe after vibration without any damage In this figurethe reinforced blanket layer using IDLmaterial was indicatedby red circles between dam and foundation In addition itwas very important to note that both surfaces were safe anddam was stable under severe seismic loading like resonancemotion In fact a good absorption of energy with respectto increase of damping was found by using IDL In case ofusing this technique displacement in both edges of the crestwith negative value indicated the uplift situation Moreoverrelative displacement was like the first model Thereforedam behavior before and after reinforcement was similar forboth distributions of displacement Nevertheless Model Ewas successful to remove damage with respect to high levelof damping in blanket layer In fact this model shows theexcellent performance in earth dams when the blanket layerwas expanded below tank
Finally blanket layer using isolator damper layer (IDL)below dam and tank is a good recommendation for earthdams in seismic zonewhen reinforced thickness is one-fourthof damheight As recommended optimization of thickness inthis method is the next study
6 Conclusion
In this study the earth dam performance under severeseismic motion such as resonance was evaluated by usingblanket layer (IDL) With respect to soil mechanic testthe optimum mixture for IDL was designed IDL powderwas made by using some materials Main material was alocal soil (laterite) with 90 and additives such as TDA
14 Shock and Vibration
(a) (b)
(c) (d)
Figure 24 Dam stabilization in the fifth model (Model E)
(tire derived aggregate with 7) and MS (microsilica) with3 were used This material was utilized to reinforce damin small scale physical modeling According to numericalanalysis the dominant frequency (02298Hz) in order tohave maximum effect for modeling vibration was computedBy using this frequency for physical modeling the damagelocation and distribution of vertical displacement at bothedges of the crest in the middle of small dams for five smallmodel with scale 1100 were discussed As results the bestperformance in order to remove damages was obviouslyobserved in Model E while other models were dramaticallydamaged in some locations such as upstream downstreamand crest In addition the thickness of blanket layer in thismodel was one-fourth of dam height Finally this model is anovel method to reinforce dam under strong earthquake likeresonance phenomena recommended for earth dam designin seismic zone
Conflict of Interests
The authors declare that there is no conflict of interestsregarding the publication of this paper
Acknowledgment
This study ismade possible by the support of the InternationalDoctorate Fellowship of Universiti Teknologi Malaysia andit is very much appreciated
References
[1] M Zeghal and A M Abdel-Ghaffar ldquoAnalysis of behavior ofearth dam using strong-motion earthquakes recordsrdquo Journalof Geotechnical Engineering vol 118 no 2 pp 266ndash277 1992
[2] V Gikas andM Sakellariou ldquoSettlement analysis of theMornosearth dam (Greece) evidence from numerical modeling andgeodetic monitoringrdquo Engineering Structures vol 30 no 11 pp3074ndash3081 2008
[3] R Verdugo N Sitar J D Frost et al ldquoSeismic performanceof earth structures during the February 2010 Maule Chileearthquake dams levees tailings dams and retaining wallsrdquoEarthquake Spectra vol 28 no 1 pp S75ndashS96 2012
[4] Y Parish and F N Abadi ldquoDynamic behaviour of earth damsfor variation of earth material stiffnessrdquo Proceedings of WorldAcademy of Science Engineering and Technology vol 50 pp606ndash611 2009
[5] T G Berhe X T Wang and W Wu ldquoNumerical investigationinto the arrangement of clay core on the seismic performanceof earth damsrdquo in Proceedings of the GeoShanghai InternationalConference on Soil Dynamics and Earthquake Engineering pp131ndash138 ASCE June 2010
[6] Z F Xia G L Ye J HWang B Ye and F Zhang ldquoFully couplednumerical analysis of repeated shake-consolidation process ofearth embankment on liquefiable foundationrdquo Soil Dynamicsand Earthquake Engineering vol 30 no 11 pp 1309ndash1318 2010
[7] X J Kong Y Zhou B Xu and D G Zou ldquoAnalysis on seismicfailure mechanism of Zipingpu dam and several reflections ofaseismic design for high rock-fill damrdquo in Proceedings of theEarth and Space pp 3177ndash3189 March 2010
Shock and Vibration 15
[8] A BayraktarM E Kartal and S Adanur ldquoThe effect of concreteslabrockfill interface behavior on the earthquake performanceof a CFR damrdquo International Journal of Non-Linear Mechanicsvol 46 no 1 pp 35ndash46 2011
[9] R P Piao A H Rippe B Myers and K W Lane ldquoEarthdam liquefaction and deformation analysis using numericalmodelingrdquo in Proceedings of the GeoCongress pp 1ndash6 March2006
[10] A W Elgamal ldquoThree-dimensional seismic analysis of la villitadamrdquo Journal of Geotechnical Engineering vol 118 no 12 pp1937ndash1958 1992
[11] B Gordan and B A Azlan ldquoEffect of material properties inCFRD tailing-embankment bridge during a strong earthquakerdquoCaspian Journal of Applied Sciences Research vol 2 no 11 pp61ndash72 2013
[12] A Papalou and J Bielak ldquoSeismic elastic response of Earthdams with canyon interactionrdquo Journal of Geotechnical andGeoenvironmental Engineering vol 127 no 5 pp 446ndash453 2001
[13] Y Yu L Xie and B Zhang ldquoStability of earth-rockfill damsinfluence of geometry on the three-dimensional effectrdquo Com-puters and Geotechnics vol 32 no 5 pp 326ndash339 2005
[14] L H Mejia and H B Seed ldquoComparison of 2-D and 3-D dynamic analyses of earth damsrdquo Journal of GeotechnicalEngineering vol 109 no 11 pp 1383ndash1398 1983
[15] J L Borges ldquoThree-dimensional analysis of embankmentson soft soils incorporating vertical drains by finite elementmethodrdquoComputers andGeotechnics vol 31 no 8 pp 665ndash6762004
[16] A Yildiz ldquoNumerical analyses of embankments on PVDimproved soft claysrdquo Advances in Engineering Software vol 40no 10 pp 1047ndash1055 2009
[17] B Le Hello and P Villard ldquoEmbankments reinforced by pilesand geosynthetics-Numerical and experimental studies dealingwith the transfer of load on the soil embankmentrdquo EngineeringGeology vol 106 no 1-2 pp 78ndash91 2009
[18] S W Abusharar J J Zheng B G Chen and J H Yin ldquoA sim-plified method for analysis of a piled embankment reinforcedwith geosyntheticsrdquo Geotextiles and Geomembranes vol 27 no1 pp 39ndash52 2009
[19] R Noorzad and M Omidvar ldquoSeismic displacement analysisof embankment dams with reinforced cohesive shellrdquo SoilDynamics and Earthquake Engineering vol 30 no 11 pp 1149ndash1157 2010
[20] T Matsumaru K Watanabe and J Isono ldquoApplication ofcement-mixed gravel reinforced by ground for soft groundimprovementrdquo in Proceedings of the 4th Asian Regional Confer-ence on Geosynthetics pp 380ndash385 Shanghai China June 2008
[21] Namdar and A A K Pelko ldquoSeismic evaluation of embank-ment shaking table test and finite element methodrdquo ThePacific Journal of Science and Technology vol 11 no 2 2010httpwwwakamaiuniversityusPJST
[22] L Wang G Zhang and J Zhang ldquoCentrifuge model tests ofgeotextile-reinforced soil embankments during an earthquakerdquoGeotextiles and Geomembranes vol 29 no 3 pp 222ndash232 2011
[23] H B Seed R T Wong I M Idriss and K Tokimatsu ldquoModuliand damping factors for dynamic analyses of cohesionless soilsrdquoJournal of Geotechnical Engineering vol 112 no 11 pp 1016ndash1032 1986
[24] B M Das Advanced Soil Mechanics CRC Press New York NYUSA 2013
[25] M J Griffin Handbook of Human Vibration Academic PressNew York NY USA 2012
[26] J Garnier C Gaudin S M Springman P J Culligan DJ Goodings and D Konig ldquoCatalogue of scaling laws andsimilitude questions in geotechnical centrifuge modellingrdquoInternational Journal of Physical Modelling in Geotechnics vol7 no 3 pp 1ndash23 2007
[27] A Fluent 120 Userrsquos Guide User Inputs for PorousMedia 2009
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Shock and Vibration
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Modelling amp Simulation in EngineeringHindawi Publishing Corporation httpwwwhindawicom Volume 2014
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International Journal of
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DistributedSensor Networks
International Journal of
6 Shock and Vibration
Stress
Strain
(a)
Stress
Strain
(b)
Figure 9 Damping definition and hysteretic and equivalent bilinear stress-strain relationships for soil (a) stress-strain curves (b) bilinearidealization [23]
400
300
200
100
0
minus100
minus200
minus300
minus400
minus003 minus002 minus001 0 001 002 003
0020
00168
00225Stress (kPa)
Strain
Blue area = 377
Loop area = 850
Damping = 01795
Hysteresis loop-sample 1
(a)
250200150100500
minus50minus100minus150minus200minus250
minus006 minus004 minus002 0 002 004 006
00425
0034
00404
Stress (kPa)
Strain
Hysteresis loop-sample 10
Blue area = 421Loop area = 1197
Damping = 02263
(b)
Figure 10 Estimation of damping ratio (a) sample 1 and (b) sample 10
Figure 11 Vibrator table
equal to two seconds based on device ability with respect toprint
33 Sinusoidal Vibrate Loading There is a mathematicalrelationship between frequency displacement velocity andacceleration for sinusoidalmotion according to considerationof the peak value for them The relationship is such that ifany two of the four variables are known the other two can becalculated Table 5 shows all equations that were provided inthis context [25]
Table 5 Conversion for peak value in sinusoidal motion displace-ment (X) velocity (V) acceleration (A) and frequency (f )
Displacement X Velocity V Acceleration A
Displacement X 119883 = 119883 119883 =119881
2120587119891119883 =
119860
(2120587119891)2
Velocity V 119881 = 2120587119891119883 119881 = 119881 119881 =119860
2120587119891
Acceleration A 119860 = (2120587119891)2
119883 119860 = 2120587119891119881 119860 = 119860
119866 in these formulas is not gravity acceleration It is aconstant for calculation within different systems Respec-tively for metric imperial and Si 119866 is 980665ms23860885827 ins2 and 100ms2
Since themotion is sinusoidal the displacement velocityand acceleration are changing sinusoidal trend Howeverthey are not in the same phase The phase relationshipbetween displacement velocity and acceleration is that veloc-ity is 90∘ out of phase with acceleration and displacement is180∘ out of phase with acceleration
Shock and Vibration 7
(a)
CDP-D
12060110120601D
10
120601E
C A
120601BInputoutput 1Inputoutput 2
2 inputoutput cables
Dimensions
TypeCDP-50-D
A B C D E
165 335 65 5 10
(b)
(c)
Figure 12 Transducer and data logger (a) Displacement transducer CDP-100 (b) dimension of displacement transducer (CDP-100) and (c)data logger UCAM-70A
155
minus5minus15
20100
minus10minus20
25155
minus5minus15minus25
Displacement 13mm peak
Velocity 16336ms peak
Acceleration 2090gn peak
Figure 13 20Hz sinusoidal motion
In other words when displacement is at a maximumvelocity is at a minimum and acceleration is at a maximumIt should be noted that 1 119892
119899
= 980665ms2 = 32174 fts2 =3860886 ins2 Figure 13 shows the example of displacementdistribution with velocity and acceleration while the fre-quency of sinusoidal motion is twenty hertz
34 Scaling Laws In case of the scale parameter the scalefactor can be used according to
119909lowast
=119909119898
119909119901
(2)
The subscript 119898 represents ldquomodelrdquo and the subscript 119901represents ldquoprototyperdquo and 119909lowast represents the scale factor forthe quantity 119909 [26]
k
mx
Figure 14 Mass spring system
Figure 15 Free mesh
The reason for spinning a model on a centrifuge is toenable small scale models to feel the same effective stresses asa full scale prototype This goal can be stated mathematicallyas
1205901015840119909
=1205901015840
119898
1205901015840
119901
= 1 (3)
where the asterisk represents the scaling factor for thequantity 1205901015840
119898
is the effective stress in the model and 1205901015840119901
is theeffective stress in the prototype
8 Shock and Vibration
Nodal solutionStep = 1
UX (Avg)RSYS = 0
DMX = 0288E minus 03
SMX = 0271E minus 04
Sub = 1X
Y
Z
MN
MX
minus0271E
minus04
minus0210E
minus04
minus0150E
minus04
minus0902Eminus05
minus0301Eminus05
0301Eminus05
0902Eminus05
0150E
minus04
0210E
minus04
0271E
minus04
SMN = minus0271E minus 04
Freq = 0229855
(a)
Nodal solutionStep = 1
Sub = 1
UY (Avg)RSYS = 0
DMX = 0288E minus 03
SMX = 0126E minus 03
X
Y
Z
MN
MX
minus0971E
minus04
minus0125E
minus03
minus0692E
minus04
minus0413Eminus04
minus0134Eminus04
0145Eminus04
0423E
minus04
0702E
minus04
0981E
minus04
0126E
minus03
SMN = minus0125E minus 03
Freq = 0229855
(b)
X
Y
Z MN
MX
0
0287E
minus04
0575E
minus04
0862Eminus04
0115Eminus03
0144Eminus03
0172Eminus03
0201E
minus03
0230E
minus03
0259E
minus03
Nodal solutionStep = 1
UZ (Avg)RSYS = 0
DMX = 0288E minus 03
SMX = 0259E minus 03
Sub = 1
Freq = 0229855
(c)
X
Y
Z
MX0
0320E
minus04
0639E
minus04
0959Eminus04
0128Eminus03
0160Eminus03
0192Eminus03
0224E
minus03
0256E
minus03
0288E
minus03
Nodal solutionStep = 1
Sub = 1
USUM (Avg)RSYS = 0
DMX = 0288E minus 03
SMX = 0288E minus 03
MN
Freq = 0229855
(d)
Figure 16 Mode shape 1 (a) horizontal displacement (b) vertical displacement (c) lateral displacement and (d) total displacement
In soil mechanics the vertical effective stress 1205901015840 forexample is typically calculated by
1205901015840
= 120590119905
minus 119906 (4)
where 120590119905 and 119906 are total stress and pore pressure respectivelyFor a uniform layer with no pore pressure the total verticalstress at a depth119867may be calculated by
120590119905
= 120588119892119867 (5)
where 120588 represents the density of the layer and 119892 representsgravity In the conventional form of centrifugemodeling [26]it is typical that the same materials are used in the model andprototype therefore the densities are the same in model andprototype that is
120588lowast
= 1 (6)
Furthermore in conventional centrifugemodeling all lengthsare scaled by the same factor 119871lowast To produce the same stressin the model as in the prototype we thus require
120588lowast
119892lowast
119867lowast
= 1119892lowast
119871lowast
= 1 (7)
It may be rewritten as
119892lowast
=1
119871lowast
(8)
The above scaling law states that if lengths in the model arereduced by some factor 119899 then gravitational accelerationsmust be increased by the same factor 119899 in order to preserveequal stresses in model and prototype
Shock and Vibration 9
1650
950
500 5200 500
1000
1000785
Laterite
Water
Sand
(a)
1650
950
500 5200 500
1000
1000785
Laterite
Water
Sand
(b)
1650
950
500 5200 500
1000
1000785
Laterite
Water
Sand
(c)
1650
950
500 5200 500
1000
1000785 Water
Sand
Laterite reinforced
(d)
1650
950
1000
1000785
Laterite
Water
Sand
500 5200 500
(e)
Figure 17 Model introducing ((a) (b) (c) (d) and (e)) for small dam (cm) (119878 = 1100)
For dynamic problems where gravity and accelerationsare important all accelerations must scale as gravity is scaledthat is
119886lowast
= 119892lowast
=1
119871lowast
(9)
Since acceleration has units of 1198711198792 it is required that
119886lowast
=119871lowast
1198792
(10)
Hence it is required that
1
119871lowast
=119871lowast
1198792
or 119879lowast
= 119871lowast
(11)
Frequency has units of inverse of time and velocity has unitsof length per time so for dynamic problems we also obtain
119891lowast
=1
119871lowast
Vlowast =119871lowast
119879lowast
= 1 (12)
For model tests involving dynamics the conflict in time scalefactors may be resolved by scaling the permeability of the soil[26]
35 Free Vibration Analysis In dynamic assessment freevibration analysis is the base of study In fact the distributionof frequency in the different vibrationmode can be computedby the application of modal analysis based on finite-elementmethod (FEM) It is worth mentioning that this analysis isperfectly related to the mass and spring In case of the mass-spring-damper system the first assumption is negligibleabout damping effect Therefore there is not any externalforce on mass in this state The force applied to the massby the spring is proportional to the amount of the springthat is stretched ldquo119909rdquo (it can be assumed that spring isalready compressed due to the weight of the mass) Theproportionality constant (119896) is spring stiffness (see Figure 14)The unit measurement is force divided by distance (kgm)
10 Shock and Vibration
(a) (b)
(c) (d)
Figure 18 Small scale dam (a) Dam perspective with two LVDT (b) soil compaction with roller (c) dam section with index network and(d) dam with tank before vibration
The negative sign indicates that force is always opposingthe motion of the mass attached to it according to thefollowing equation
119865119904
= minus119896119909 (13)
The force generated by the mass is proportional to theacceleration of the mass as given by Newtonrsquos second law ofmotion
sum119865 = 119898119886 = 119898 = 1198981198892
119909
1198891199052
(14)
The sumof the forces on themass then generates this ordinarydifferential equation
119898 + 119896119909 = 0 (15)
Assuming that the initial vibration can be started by stretch-ing and releasing the spring with distance (119860) the solution tothe above equation that describes the motion of mass can beseen in the following equation
119909 (119905) = 119860 cos (2120587119891119899
119905) (16)
This solution shows that it will oscillate with simple harmonicmotion that has amplitude of (119860) and a frequency (119891
119899
) Thenumber (119891
119899
) is called the undamped natural frequency Forthe simple mass-spring system frequency is given by
119891119899
=1
2120587
radic119896
119898 (17)
However the relation between frequency and vibrationperiod is always reverse Consider
119879 =1
119891 (18)
In terms of the measurement unit the vibration periodand frequency were according to seconds and hertz It isworth noting that the dominant frequency is the minimumfrequency to produce maximum vibration period
4 Numerical Analysis
In terms of numerical analysismodal analysis was carried outby using ANSYS program in this study to compute dominantfrequency for small scale model regarding 3D analysis Thisprogram is one of the famous software programs with respectto finite-elementmethod (FEM) In particular this software isone of the universal programs with high level of the ability fordifferent analyses A strong ability to compute free vibrationanalysis is possible with modal analysis [27]
41 Elements and Meshing Process To select element basedon Help menu solid 8 nodes 183 (3D) were used for thispurpose Figure 15 shows the mapped mesh for numericalmodeling In this figure 23956 elements and 35457 nodes inmodels were used for free vibration analysis According tothis condition free vibration analysis to access frequency indifferent vibration modes was carried out as results can bediscussed in the next section
Shock and Vibration 11
0 20 40 60 80 100 1200
minus01
minus02
minus03
minus04
minus05
minus06
62 minus029
90 minus048
Time (s)
Disp
lace
men
t (m
m)
Time (s)0 10 20 30 40 50 60 70 80 90 100 110 120
03
025
02
015
01
005
0
Rela
tive
disp
lace
men
t (m
m)
96 024
Model A
0 20 40 60 80 100 120
Time (s)
Disp
lace
men
t (m
m) 2
15
1
05
0
minus05
minus1
minus15
84 15
104 minus064
Time (s)0 10 20 30 40 50 60 70 80 90 100 110 120
Rela
tive
disp
lace
men
t (m
m) 25
2
15
1
05
0
minus05
minus1
104 213
Model B
0 20 40 60 80 100 120
Time (s)
Disp
lace
men
t (m
m)
01201008006004002
0minus002minus004
108 01
108 006
Time (s)
0 10 20 30 40 50 60 70 80 90 100 110 120
Rela
tive
disp
lace
men
t (m
m)
007
006
005
004
003
002
001
0
8 006
Model C
Time (s)0 10 20 30 40 50 60 70 80 90 100 110 120
Rela
tive
disp
lace
men
t (m
m)
0201501005
0minus005minus01minus015minus02
90 017
26 minus017
0 20 40 60 80 100 120
Time (s)
Disp
lace
men
t (m
m) 015
01005
0
minus01minus015
minus005
minus02minus025
114 minus007116 minus022
Model DTime (s)
Disp
lace
men
t (m
m)
01
0
minus01
minus02
minus03
minus04
104 minus011
102 minus033
0 20 40 60 80 100 120
Up streamDown stream
Time (s)
0 10 20 30 40 50 60 70 80 90 100 110 120
Rela
tive
disp
lace
men
t (m
m)
03
025
02
015
01
0
005
86 025
Model E
Figure 19 Vertical displacement in both edges of the crest in models with relative displacement
12 Shock and Vibration
(a) (b) (c)
Figure 20 Damage in the first model (Model A)
(a) (b)
(c) (d)
Figure 21 Damage in the second model (Model B)
42 Free Vibration Analysis and Dominant Frequency Interms of modal analysis the free vibration analysis was cal-culated by ANSYS program Figure 16 shows displacement inthree directions of model and total displacement in the firstvibration mode because based on distribution of frequencyin the first mode to fifth mode it is important to note thatthe minimum frequency (022986Hz) was observed in thefirst vibration mode It means that the vibration period wasmaximum and critical in this mode
Distribution of frequency in different vibration modesindicated that this value was respectively obtained at026257Hz 028387Hz and 030135Hz in the vibration shapemodes 2 to 4
5 Results and Discussion Based on PhysicalSmall Scale Modeling
In order to find the best location of reinforcement in damfive small dams with different locations of reinforcementusing IDL material were vibrated by dominant frequency
(22986Hz) with respect to resonance condition Figure 17shows five small scale dams (Models (a) (b) (c) and (d))it is obvious that models have the same dimension In thisfigure the reinforced area was illustrated with a hatch areaFor example Model (d) indicated that all dam body wasreinforced For this purpose one steel box for modeling wasused This box made by five sheets of Plexiglas with 20mmthickness One of them was in the base of model The levelof reservoir was 75 of the dam height The scale parameterwas 1100 Itmeans thatmodel was one hundred times smallerthan prototypeThedamheightwas 227meter in reality but itwas made 227 cm in physical model In addition small scalemodeling was coupled by foundation Foundation materialwas dense sand with 75 relative density Sand propertieswere mentioned in soil mechanic test Figure 18 shows somedetails including dam perspective soil compaction networkindex and reservoir In this Figure two LVDT on the middleof model at the both edges of the crest were installed Inorder to achieve support one steel frame and one steel beamwere applied (see Figure 18(a)) However both LVDT wereconnected to data logger device by specific cables In terms
Shock and Vibration 13
(a) (b)
Figure 22 Damage in the third model (Model C)
of compaction soil for each layer the steel roller used wasselected by trial error methodWoodmolding with respect tocontrol slope via network index was used In order to avoidabsorption of soil water content both the described moldswere just soaked by water before use For tank purpose smallscale models were filled up by water with very slow rate
After vibration equal to two minutes for all modelsthe vertical displacement for both slopes such as upstreamand downstream were printed With respect to use of Excelprogram Figure 19 shows the distribution of vertical displace-ment in both edges in the middle of the crest and relativedisplacement in all models It was obvious that distributionof the vertical displacement indicated a same trend for bothmodels such as A and E In both models displacement valueswere negative during the vibration It means that both ofthem were in uplift condition In this figure also maximumandminimum peak of the relative displacement respectivelyoccurred in Models B and C with 213mm and 006mm It isalso worth noting that this value was at convergence positionfor Models A and E with 024mm and 025mm respectively
In terms of damage location in models Figure 20 showsthe damage in Model A which occurred at upstream anddownstream The level of damage was greater in upstream Itwas very sensible occurrence in case of hydrodynamic pres-sure along the vibration Also in this figure the maximumlongitudes cracks (see line C) were observed near to themiddle of dam at the crest For damage at downstream thetransverse cracks significantly occurred in dam toe
Figure 21 shows Model B that was damaged after vibra-tion It can be observed that dam was significantly damagedin some locations such as crest and surfaces Body cracks andfailure process dramatically occurred in both areas near toabutments Also in this figure one transverse crack in themiddle of the crest was seen (see Figure 20(c)) This damagewas significantly repeated at upstream in Model C but itwas placed in dam toe and it can be seen in Figure 22 Inaddition Model D was damaged in three places such as bothabutments and the middle of the upstream Figure 23 showsModel D that was damaged in toe Briefly all four modelswere damaged as discussed previously On the other handa successful way in order to remove damage was obtained inModel E as shown in Figure 24 Figure 24 shows that model
Figure 23 Damage in the fourth model (Model D)
was safe after vibration without any damage In this figurethe reinforced blanket layer using IDLmaterial was indicatedby red circles between dam and foundation In addition itwas very important to note that both surfaces were safe anddam was stable under severe seismic loading like resonancemotion In fact a good absorption of energy with respectto increase of damping was found by using IDL In case ofusing this technique displacement in both edges of the crestwith negative value indicated the uplift situation Moreoverrelative displacement was like the first model Thereforedam behavior before and after reinforcement was similar forboth distributions of displacement Nevertheless Model Ewas successful to remove damage with respect to high levelof damping in blanket layer In fact this model shows theexcellent performance in earth dams when the blanket layerwas expanded below tank
Finally blanket layer using isolator damper layer (IDL)below dam and tank is a good recommendation for earthdams in seismic zonewhen reinforced thickness is one-fourthof damheight As recommended optimization of thickness inthis method is the next study
6 Conclusion
In this study the earth dam performance under severeseismic motion such as resonance was evaluated by usingblanket layer (IDL) With respect to soil mechanic testthe optimum mixture for IDL was designed IDL powderwas made by using some materials Main material was alocal soil (laterite) with 90 and additives such as TDA
14 Shock and Vibration
(a) (b)
(c) (d)
Figure 24 Dam stabilization in the fifth model (Model E)
(tire derived aggregate with 7) and MS (microsilica) with3 were used This material was utilized to reinforce damin small scale physical modeling According to numericalanalysis the dominant frequency (02298Hz) in order tohave maximum effect for modeling vibration was computedBy using this frequency for physical modeling the damagelocation and distribution of vertical displacement at bothedges of the crest in the middle of small dams for five smallmodel with scale 1100 were discussed As results the bestperformance in order to remove damages was obviouslyobserved in Model E while other models were dramaticallydamaged in some locations such as upstream downstreamand crest In addition the thickness of blanket layer in thismodel was one-fourth of dam height Finally this model is anovel method to reinforce dam under strong earthquake likeresonance phenomena recommended for earth dam designin seismic zone
Conflict of Interests
The authors declare that there is no conflict of interestsregarding the publication of this paper
Acknowledgment
This study ismade possible by the support of the InternationalDoctorate Fellowship of Universiti Teknologi Malaysia andit is very much appreciated
References
[1] M Zeghal and A M Abdel-Ghaffar ldquoAnalysis of behavior ofearth dam using strong-motion earthquakes recordsrdquo Journalof Geotechnical Engineering vol 118 no 2 pp 266ndash277 1992
[2] V Gikas andM Sakellariou ldquoSettlement analysis of theMornosearth dam (Greece) evidence from numerical modeling andgeodetic monitoringrdquo Engineering Structures vol 30 no 11 pp3074ndash3081 2008
[3] R Verdugo N Sitar J D Frost et al ldquoSeismic performanceof earth structures during the February 2010 Maule Chileearthquake dams levees tailings dams and retaining wallsrdquoEarthquake Spectra vol 28 no 1 pp S75ndashS96 2012
[4] Y Parish and F N Abadi ldquoDynamic behaviour of earth damsfor variation of earth material stiffnessrdquo Proceedings of WorldAcademy of Science Engineering and Technology vol 50 pp606ndash611 2009
[5] T G Berhe X T Wang and W Wu ldquoNumerical investigationinto the arrangement of clay core on the seismic performanceof earth damsrdquo in Proceedings of the GeoShanghai InternationalConference on Soil Dynamics and Earthquake Engineering pp131ndash138 ASCE June 2010
[6] Z F Xia G L Ye J HWang B Ye and F Zhang ldquoFully couplednumerical analysis of repeated shake-consolidation process ofearth embankment on liquefiable foundationrdquo Soil Dynamicsand Earthquake Engineering vol 30 no 11 pp 1309ndash1318 2010
[7] X J Kong Y Zhou B Xu and D G Zou ldquoAnalysis on seismicfailure mechanism of Zipingpu dam and several reflections ofaseismic design for high rock-fill damrdquo in Proceedings of theEarth and Space pp 3177ndash3189 March 2010
Shock and Vibration 15
[8] A BayraktarM E Kartal and S Adanur ldquoThe effect of concreteslabrockfill interface behavior on the earthquake performanceof a CFR damrdquo International Journal of Non-Linear Mechanicsvol 46 no 1 pp 35ndash46 2011
[9] R P Piao A H Rippe B Myers and K W Lane ldquoEarthdam liquefaction and deformation analysis using numericalmodelingrdquo in Proceedings of the GeoCongress pp 1ndash6 March2006
[10] A W Elgamal ldquoThree-dimensional seismic analysis of la villitadamrdquo Journal of Geotechnical Engineering vol 118 no 12 pp1937ndash1958 1992
[11] B Gordan and B A Azlan ldquoEffect of material properties inCFRD tailing-embankment bridge during a strong earthquakerdquoCaspian Journal of Applied Sciences Research vol 2 no 11 pp61ndash72 2013
[12] A Papalou and J Bielak ldquoSeismic elastic response of Earthdams with canyon interactionrdquo Journal of Geotechnical andGeoenvironmental Engineering vol 127 no 5 pp 446ndash453 2001
[13] Y Yu L Xie and B Zhang ldquoStability of earth-rockfill damsinfluence of geometry on the three-dimensional effectrdquo Com-puters and Geotechnics vol 32 no 5 pp 326ndash339 2005
[14] L H Mejia and H B Seed ldquoComparison of 2-D and 3-D dynamic analyses of earth damsrdquo Journal of GeotechnicalEngineering vol 109 no 11 pp 1383ndash1398 1983
[15] J L Borges ldquoThree-dimensional analysis of embankmentson soft soils incorporating vertical drains by finite elementmethodrdquoComputers andGeotechnics vol 31 no 8 pp 665ndash6762004
[16] A Yildiz ldquoNumerical analyses of embankments on PVDimproved soft claysrdquo Advances in Engineering Software vol 40no 10 pp 1047ndash1055 2009
[17] B Le Hello and P Villard ldquoEmbankments reinforced by pilesand geosynthetics-Numerical and experimental studies dealingwith the transfer of load on the soil embankmentrdquo EngineeringGeology vol 106 no 1-2 pp 78ndash91 2009
[18] S W Abusharar J J Zheng B G Chen and J H Yin ldquoA sim-plified method for analysis of a piled embankment reinforcedwith geosyntheticsrdquo Geotextiles and Geomembranes vol 27 no1 pp 39ndash52 2009
[19] R Noorzad and M Omidvar ldquoSeismic displacement analysisof embankment dams with reinforced cohesive shellrdquo SoilDynamics and Earthquake Engineering vol 30 no 11 pp 1149ndash1157 2010
[20] T Matsumaru K Watanabe and J Isono ldquoApplication ofcement-mixed gravel reinforced by ground for soft groundimprovementrdquo in Proceedings of the 4th Asian Regional Confer-ence on Geosynthetics pp 380ndash385 Shanghai China June 2008
[21] Namdar and A A K Pelko ldquoSeismic evaluation of embank-ment shaking table test and finite element methodrdquo ThePacific Journal of Science and Technology vol 11 no 2 2010httpwwwakamaiuniversityusPJST
[22] L Wang G Zhang and J Zhang ldquoCentrifuge model tests ofgeotextile-reinforced soil embankments during an earthquakerdquoGeotextiles and Geomembranes vol 29 no 3 pp 222ndash232 2011
[23] H B Seed R T Wong I M Idriss and K Tokimatsu ldquoModuliand damping factors for dynamic analyses of cohesionless soilsrdquoJournal of Geotechnical Engineering vol 112 no 11 pp 1016ndash1032 1986
[24] B M Das Advanced Soil Mechanics CRC Press New York NYUSA 2013
[25] M J Griffin Handbook of Human Vibration Academic PressNew York NY USA 2012
[26] J Garnier C Gaudin S M Springman P J Culligan DJ Goodings and D Konig ldquoCatalogue of scaling laws andsimilitude questions in geotechnical centrifuge modellingrdquoInternational Journal of Physical Modelling in Geotechnics vol7 no 3 pp 1ndash23 2007
[27] A Fluent 120 Userrsquos Guide User Inputs for PorousMedia 2009
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Shock and Vibration
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DistributedSensor Networks
International Journal of
Shock and Vibration 7
(a)
CDP-D
12060110120601D
10
120601E
C A
120601BInputoutput 1Inputoutput 2
2 inputoutput cables
Dimensions
TypeCDP-50-D
A B C D E
165 335 65 5 10
(b)
(c)
Figure 12 Transducer and data logger (a) Displacement transducer CDP-100 (b) dimension of displacement transducer (CDP-100) and (c)data logger UCAM-70A
155
minus5minus15
20100
minus10minus20
25155
minus5minus15minus25
Displacement 13mm peak
Velocity 16336ms peak
Acceleration 2090gn peak
Figure 13 20Hz sinusoidal motion
In other words when displacement is at a maximumvelocity is at a minimum and acceleration is at a maximumIt should be noted that 1 119892
119899
= 980665ms2 = 32174 fts2 =3860886 ins2 Figure 13 shows the example of displacementdistribution with velocity and acceleration while the fre-quency of sinusoidal motion is twenty hertz
34 Scaling Laws In case of the scale parameter the scalefactor can be used according to
119909lowast
=119909119898
119909119901
(2)
The subscript 119898 represents ldquomodelrdquo and the subscript 119901represents ldquoprototyperdquo and 119909lowast represents the scale factor forthe quantity 119909 [26]
k
mx
Figure 14 Mass spring system
Figure 15 Free mesh
The reason for spinning a model on a centrifuge is toenable small scale models to feel the same effective stresses asa full scale prototype This goal can be stated mathematicallyas
1205901015840119909
=1205901015840
119898
1205901015840
119901
= 1 (3)
where the asterisk represents the scaling factor for thequantity 1205901015840
119898
is the effective stress in the model and 1205901015840119901
is theeffective stress in the prototype
8 Shock and Vibration
Nodal solutionStep = 1
UX (Avg)RSYS = 0
DMX = 0288E minus 03
SMX = 0271E minus 04
Sub = 1X
Y
Z
MN
MX
minus0271E
minus04
minus0210E
minus04
minus0150E
minus04
minus0902Eminus05
minus0301Eminus05
0301Eminus05
0902Eminus05
0150E
minus04
0210E
minus04
0271E
minus04
SMN = minus0271E minus 04
Freq = 0229855
(a)
Nodal solutionStep = 1
Sub = 1
UY (Avg)RSYS = 0
DMX = 0288E minus 03
SMX = 0126E minus 03
X
Y
Z
MN
MX
minus0971E
minus04
minus0125E
minus03
minus0692E
minus04
minus0413Eminus04
minus0134Eminus04
0145Eminus04
0423E
minus04
0702E
minus04
0981E
minus04
0126E
minus03
SMN = minus0125E minus 03
Freq = 0229855
(b)
X
Y
Z MN
MX
0
0287E
minus04
0575E
minus04
0862Eminus04
0115Eminus03
0144Eminus03
0172Eminus03
0201E
minus03
0230E
minus03
0259E
minus03
Nodal solutionStep = 1
UZ (Avg)RSYS = 0
DMX = 0288E minus 03
SMX = 0259E minus 03
Sub = 1
Freq = 0229855
(c)
X
Y
Z
MX0
0320E
minus04
0639E
minus04
0959Eminus04
0128Eminus03
0160Eminus03
0192Eminus03
0224E
minus03
0256E
minus03
0288E
minus03
Nodal solutionStep = 1
Sub = 1
USUM (Avg)RSYS = 0
DMX = 0288E minus 03
SMX = 0288E minus 03
MN
Freq = 0229855
(d)
Figure 16 Mode shape 1 (a) horizontal displacement (b) vertical displacement (c) lateral displacement and (d) total displacement
In soil mechanics the vertical effective stress 1205901015840 forexample is typically calculated by
1205901015840
= 120590119905
minus 119906 (4)
where 120590119905 and 119906 are total stress and pore pressure respectivelyFor a uniform layer with no pore pressure the total verticalstress at a depth119867may be calculated by
120590119905
= 120588119892119867 (5)
where 120588 represents the density of the layer and 119892 representsgravity In the conventional form of centrifugemodeling [26]it is typical that the same materials are used in the model andprototype therefore the densities are the same in model andprototype that is
120588lowast
= 1 (6)
Furthermore in conventional centrifugemodeling all lengthsare scaled by the same factor 119871lowast To produce the same stressin the model as in the prototype we thus require
120588lowast
119892lowast
119867lowast
= 1119892lowast
119871lowast
= 1 (7)
It may be rewritten as
119892lowast
=1
119871lowast
(8)
The above scaling law states that if lengths in the model arereduced by some factor 119899 then gravitational accelerationsmust be increased by the same factor 119899 in order to preserveequal stresses in model and prototype
Shock and Vibration 9
1650
950
500 5200 500
1000
1000785
Laterite
Water
Sand
(a)
1650
950
500 5200 500
1000
1000785
Laterite
Water
Sand
(b)
1650
950
500 5200 500
1000
1000785
Laterite
Water
Sand
(c)
1650
950
500 5200 500
1000
1000785 Water
Sand
Laterite reinforced
(d)
1650
950
1000
1000785
Laterite
Water
Sand
500 5200 500
(e)
Figure 17 Model introducing ((a) (b) (c) (d) and (e)) for small dam (cm) (119878 = 1100)
For dynamic problems where gravity and accelerationsare important all accelerations must scale as gravity is scaledthat is
119886lowast
= 119892lowast
=1
119871lowast
(9)
Since acceleration has units of 1198711198792 it is required that
119886lowast
=119871lowast
1198792
(10)
Hence it is required that
1
119871lowast
=119871lowast
1198792
or 119879lowast
= 119871lowast
(11)
Frequency has units of inverse of time and velocity has unitsof length per time so for dynamic problems we also obtain
119891lowast
=1
119871lowast
Vlowast =119871lowast
119879lowast
= 1 (12)
For model tests involving dynamics the conflict in time scalefactors may be resolved by scaling the permeability of the soil[26]
35 Free Vibration Analysis In dynamic assessment freevibration analysis is the base of study In fact the distributionof frequency in the different vibrationmode can be computedby the application of modal analysis based on finite-elementmethod (FEM) It is worth mentioning that this analysis isperfectly related to the mass and spring In case of the mass-spring-damper system the first assumption is negligibleabout damping effect Therefore there is not any externalforce on mass in this state The force applied to the massby the spring is proportional to the amount of the springthat is stretched ldquo119909rdquo (it can be assumed that spring isalready compressed due to the weight of the mass) Theproportionality constant (119896) is spring stiffness (see Figure 14)The unit measurement is force divided by distance (kgm)
10 Shock and Vibration
(a) (b)
(c) (d)
Figure 18 Small scale dam (a) Dam perspective with two LVDT (b) soil compaction with roller (c) dam section with index network and(d) dam with tank before vibration
The negative sign indicates that force is always opposingthe motion of the mass attached to it according to thefollowing equation
119865119904
= minus119896119909 (13)
The force generated by the mass is proportional to theacceleration of the mass as given by Newtonrsquos second law ofmotion
sum119865 = 119898119886 = 119898 = 1198981198892
119909
1198891199052
(14)
The sumof the forces on themass then generates this ordinarydifferential equation
119898 + 119896119909 = 0 (15)
Assuming that the initial vibration can be started by stretch-ing and releasing the spring with distance (119860) the solution tothe above equation that describes the motion of mass can beseen in the following equation
119909 (119905) = 119860 cos (2120587119891119899
119905) (16)
This solution shows that it will oscillate with simple harmonicmotion that has amplitude of (119860) and a frequency (119891
119899
) Thenumber (119891
119899
) is called the undamped natural frequency Forthe simple mass-spring system frequency is given by
119891119899
=1
2120587
radic119896
119898 (17)
However the relation between frequency and vibrationperiod is always reverse Consider
119879 =1
119891 (18)
In terms of the measurement unit the vibration periodand frequency were according to seconds and hertz It isworth noting that the dominant frequency is the minimumfrequency to produce maximum vibration period
4 Numerical Analysis
In terms of numerical analysismodal analysis was carried outby using ANSYS program in this study to compute dominantfrequency for small scale model regarding 3D analysis Thisprogram is one of the famous software programs with respectto finite-elementmethod (FEM) In particular this software isone of the universal programs with high level of the ability fordifferent analyses A strong ability to compute free vibrationanalysis is possible with modal analysis [27]
41 Elements and Meshing Process To select element basedon Help menu solid 8 nodes 183 (3D) were used for thispurpose Figure 15 shows the mapped mesh for numericalmodeling In this figure 23956 elements and 35457 nodes inmodels were used for free vibration analysis According tothis condition free vibration analysis to access frequency indifferent vibration modes was carried out as results can bediscussed in the next section
Shock and Vibration 11
0 20 40 60 80 100 1200
minus01
minus02
minus03
minus04
minus05
minus06
62 minus029
90 minus048
Time (s)
Disp
lace
men
t (m
m)
Time (s)0 10 20 30 40 50 60 70 80 90 100 110 120
03
025
02
015
01
005
0
Rela
tive
disp
lace
men
t (m
m)
96 024
Model A
0 20 40 60 80 100 120
Time (s)
Disp
lace
men
t (m
m) 2
15
1
05
0
minus05
minus1
minus15
84 15
104 minus064
Time (s)0 10 20 30 40 50 60 70 80 90 100 110 120
Rela
tive
disp
lace
men
t (m
m) 25
2
15
1
05
0
minus05
minus1
104 213
Model B
0 20 40 60 80 100 120
Time (s)
Disp
lace
men
t (m
m)
01201008006004002
0minus002minus004
108 01
108 006
Time (s)
0 10 20 30 40 50 60 70 80 90 100 110 120
Rela
tive
disp
lace
men
t (m
m)
007
006
005
004
003
002
001
0
8 006
Model C
Time (s)0 10 20 30 40 50 60 70 80 90 100 110 120
Rela
tive
disp
lace
men
t (m
m)
0201501005
0minus005minus01minus015minus02
90 017
26 minus017
0 20 40 60 80 100 120
Time (s)
Disp
lace
men
t (m
m) 015
01005
0
minus01minus015
minus005
minus02minus025
114 minus007116 minus022
Model DTime (s)
Disp
lace
men
t (m
m)
01
0
minus01
minus02
minus03
minus04
104 minus011
102 minus033
0 20 40 60 80 100 120
Up streamDown stream
Time (s)
0 10 20 30 40 50 60 70 80 90 100 110 120
Rela
tive
disp
lace
men
t (m
m)
03
025
02
015
01
0
005
86 025
Model E
Figure 19 Vertical displacement in both edges of the crest in models with relative displacement
12 Shock and Vibration
(a) (b) (c)
Figure 20 Damage in the first model (Model A)
(a) (b)
(c) (d)
Figure 21 Damage in the second model (Model B)
42 Free Vibration Analysis and Dominant Frequency Interms of modal analysis the free vibration analysis was cal-culated by ANSYS program Figure 16 shows displacement inthree directions of model and total displacement in the firstvibration mode because based on distribution of frequencyin the first mode to fifth mode it is important to note thatthe minimum frequency (022986Hz) was observed in thefirst vibration mode It means that the vibration period wasmaximum and critical in this mode
Distribution of frequency in different vibration modesindicated that this value was respectively obtained at026257Hz 028387Hz and 030135Hz in the vibration shapemodes 2 to 4
5 Results and Discussion Based on PhysicalSmall Scale Modeling
In order to find the best location of reinforcement in damfive small dams with different locations of reinforcementusing IDL material were vibrated by dominant frequency
(22986Hz) with respect to resonance condition Figure 17shows five small scale dams (Models (a) (b) (c) and (d))it is obvious that models have the same dimension In thisfigure the reinforced area was illustrated with a hatch areaFor example Model (d) indicated that all dam body wasreinforced For this purpose one steel box for modeling wasused This box made by five sheets of Plexiglas with 20mmthickness One of them was in the base of model The levelof reservoir was 75 of the dam height The scale parameterwas 1100 Itmeans thatmodel was one hundred times smallerthan prototypeThedamheightwas 227meter in reality but itwas made 227 cm in physical model In addition small scalemodeling was coupled by foundation Foundation materialwas dense sand with 75 relative density Sand propertieswere mentioned in soil mechanic test Figure 18 shows somedetails including dam perspective soil compaction networkindex and reservoir In this Figure two LVDT on the middleof model at the both edges of the crest were installed Inorder to achieve support one steel frame and one steel beamwere applied (see Figure 18(a)) However both LVDT wereconnected to data logger device by specific cables In terms
Shock and Vibration 13
(a) (b)
Figure 22 Damage in the third model (Model C)
of compaction soil for each layer the steel roller used wasselected by trial error methodWoodmolding with respect tocontrol slope via network index was used In order to avoidabsorption of soil water content both the described moldswere just soaked by water before use For tank purpose smallscale models were filled up by water with very slow rate
After vibration equal to two minutes for all modelsthe vertical displacement for both slopes such as upstreamand downstream were printed With respect to use of Excelprogram Figure 19 shows the distribution of vertical displace-ment in both edges in the middle of the crest and relativedisplacement in all models It was obvious that distributionof the vertical displacement indicated a same trend for bothmodels such as A and E In both models displacement valueswere negative during the vibration It means that both ofthem were in uplift condition In this figure also maximumandminimum peak of the relative displacement respectivelyoccurred in Models B and C with 213mm and 006mm It isalso worth noting that this value was at convergence positionfor Models A and E with 024mm and 025mm respectively
In terms of damage location in models Figure 20 showsthe damage in Model A which occurred at upstream anddownstream The level of damage was greater in upstream Itwas very sensible occurrence in case of hydrodynamic pres-sure along the vibration Also in this figure the maximumlongitudes cracks (see line C) were observed near to themiddle of dam at the crest For damage at downstream thetransverse cracks significantly occurred in dam toe
Figure 21 shows Model B that was damaged after vibra-tion It can be observed that dam was significantly damagedin some locations such as crest and surfaces Body cracks andfailure process dramatically occurred in both areas near toabutments Also in this figure one transverse crack in themiddle of the crest was seen (see Figure 20(c)) This damagewas significantly repeated at upstream in Model C but itwas placed in dam toe and it can be seen in Figure 22 Inaddition Model D was damaged in three places such as bothabutments and the middle of the upstream Figure 23 showsModel D that was damaged in toe Briefly all four modelswere damaged as discussed previously On the other handa successful way in order to remove damage was obtained inModel E as shown in Figure 24 Figure 24 shows that model
Figure 23 Damage in the fourth model (Model D)
was safe after vibration without any damage In this figurethe reinforced blanket layer using IDLmaterial was indicatedby red circles between dam and foundation In addition itwas very important to note that both surfaces were safe anddam was stable under severe seismic loading like resonancemotion In fact a good absorption of energy with respectto increase of damping was found by using IDL In case ofusing this technique displacement in both edges of the crestwith negative value indicated the uplift situation Moreoverrelative displacement was like the first model Thereforedam behavior before and after reinforcement was similar forboth distributions of displacement Nevertheless Model Ewas successful to remove damage with respect to high levelof damping in blanket layer In fact this model shows theexcellent performance in earth dams when the blanket layerwas expanded below tank
Finally blanket layer using isolator damper layer (IDL)below dam and tank is a good recommendation for earthdams in seismic zonewhen reinforced thickness is one-fourthof damheight As recommended optimization of thickness inthis method is the next study
6 Conclusion
In this study the earth dam performance under severeseismic motion such as resonance was evaluated by usingblanket layer (IDL) With respect to soil mechanic testthe optimum mixture for IDL was designed IDL powderwas made by using some materials Main material was alocal soil (laterite) with 90 and additives such as TDA
14 Shock and Vibration
(a) (b)
(c) (d)
Figure 24 Dam stabilization in the fifth model (Model E)
(tire derived aggregate with 7) and MS (microsilica) with3 were used This material was utilized to reinforce damin small scale physical modeling According to numericalanalysis the dominant frequency (02298Hz) in order tohave maximum effect for modeling vibration was computedBy using this frequency for physical modeling the damagelocation and distribution of vertical displacement at bothedges of the crest in the middle of small dams for five smallmodel with scale 1100 were discussed As results the bestperformance in order to remove damages was obviouslyobserved in Model E while other models were dramaticallydamaged in some locations such as upstream downstreamand crest In addition the thickness of blanket layer in thismodel was one-fourth of dam height Finally this model is anovel method to reinforce dam under strong earthquake likeresonance phenomena recommended for earth dam designin seismic zone
Conflict of Interests
The authors declare that there is no conflict of interestsregarding the publication of this paper
Acknowledgment
This study ismade possible by the support of the InternationalDoctorate Fellowship of Universiti Teknologi Malaysia andit is very much appreciated
References
[1] M Zeghal and A M Abdel-Ghaffar ldquoAnalysis of behavior ofearth dam using strong-motion earthquakes recordsrdquo Journalof Geotechnical Engineering vol 118 no 2 pp 266ndash277 1992
[2] V Gikas andM Sakellariou ldquoSettlement analysis of theMornosearth dam (Greece) evidence from numerical modeling andgeodetic monitoringrdquo Engineering Structures vol 30 no 11 pp3074ndash3081 2008
[3] R Verdugo N Sitar J D Frost et al ldquoSeismic performanceof earth structures during the February 2010 Maule Chileearthquake dams levees tailings dams and retaining wallsrdquoEarthquake Spectra vol 28 no 1 pp S75ndashS96 2012
[4] Y Parish and F N Abadi ldquoDynamic behaviour of earth damsfor variation of earth material stiffnessrdquo Proceedings of WorldAcademy of Science Engineering and Technology vol 50 pp606ndash611 2009
[5] T G Berhe X T Wang and W Wu ldquoNumerical investigationinto the arrangement of clay core on the seismic performanceof earth damsrdquo in Proceedings of the GeoShanghai InternationalConference on Soil Dynamics and Earthquake Engineering pp131ndash138 ASCE June 2010
[6] Z F Xia G L Ye J HWang B Ye and F Zhang ldquoFully couplednumerical analysis of repeated shake-consolidation process ofearth embankment on liquefiable foundationrdquo Soil Dynamicsand Earthquake Engineering vol 30 no 11 pp 1309ndash1318 2010
[7] X J Kong Y Zhou B Xu and D G Zou ldquoAnalysis on seismicfailure mechanism of Zipingpu dam and several reflections ofaseismic design for high rock-fill damrdquo in Proceedings of theEarth and Space pp 3177ndash3189 March 2010
Shock and Vibration 15
[8] A BayraktarM E Kartal and S Adanur ldquoThe effect of concreteslabrockfill interface behavior on the earthquake performanceof a CFR damrdquo International Journal of Non-Linear Mechanicsvol 46 no 1 pp 35ndash46 2011
[9] R P Piao A H Rippe B Myers and K W Lane ldquoEarthdam liquefaction and deformation analysis using numericalmodelingrdquo in Proceedings of the GeoCongress pp 1ndash6 March2006
[10] A W Elgamal ldquoThree-dimensional seismic analysis of la villitadamrdquo Journal of Geotechnical Engineering vol 118 no 12 pp1937ndash1958 1992
[11] B Gordan and B A Azlan ldquoEffect of material properties inCFRD tailing-embankment bridge during a strong earthquakerdquoCaspian Journal of Applied Sciences Research vol 2 no 11 pp61ndash72 2013
[12] A Papalou and J Bielak ldquoSeismic elastic response of Earthdams with canyon interactionrdquo Journal of Geotechnical andGeoenvironmental Engineering vol 127 no 5 pp 446ndash453 2001
[13] Y Yu L Xie and B Zhang ldquoStability of earth-rockfill damsinfluence of geometry on the three-dimensional effectrdquo Com-puters and Geotechnics vol 32 no 5 pp 326ndash339 2005
[14] L H Mejia and H B Seed ldquoComparison of 2-D and 3-D dynamic analyses of earth damsrdquo Journal of GeotechnicalEngineering vol 109 no 11 pp 1383ndash1398 1983
[15] J L Borges ldquoThree-dimensional analysis of embankmentson soft soils incorporating vertical drains by finite elementmethodrdquoComputers andGeotechnics vol 31 no 8 pp 665ndash6762004
[16] A Yildiz ldquoNumerical analyses of embankments on PVDimproved soft claysrdquo Advances in Engineering Software vol 40no 10 pp 1047ndash1055 2009
[17] B Le Hello and P Villard ldquoEmbankments reinforced by pilesand geosynthetics-Numerical and experimental studies dealingwith the transfer of load on the soil embankmentrdquo EngineeringGeology vol 106 no 1-2 pp 78ndash91 2009
[18] S W Abusharar J J Zheng B G Chen and J H Yin ldquoA sim-plified method for analysis of a piled embankment reinforcedwith geosyntheticsrdquo Geotextiles and Geomembranes vol 27 no1 pp 39ndash52 2009
[19] R Noorzad and M Omidvar ldquoSeismic displacement analysisof embankment dams with reinforced cohesive shellrdquo SoilDynamics and Earthquake Engineering vol 30 no 11 pp 1149ndash1157 2010
[20] T Matsumaru K Watanabe and J Isono ldquoApplication ofcement-mixed gravel reinforced by ground for soft groundimprovementrdquo in Proceedings of the 4th Asian Regional Confer-ence on Geosynthetics pp 380ndash385 Shanghai China June 2008
[21] Namdar and A A K Pelko ldquoSeismic evaluation of embank-ment shaking table test and finite element methodrdquo ThePacific Journal of Science and Technology vol 11 no 2 2010httpwwwakamaiuniversityusPJST
[22] L Wang G Zhang and J Zhang ldquoCentrifuge model tests ofgeotextile-reinforced soil embankments during an earthquakerdquoGeotextiles and Geomembranes vol 29 no 3 pp 222ndash232 2011
[23] H B Seed R T Wong I M Idriss and K Tokimatsu ldquoModuliand damping factors for dynamic analyses of cohesionless soilsrdquoJournal of Geotechnical Engineering vol 112 no 11 pp 1016ndash1032 1986
[24] B M Das Advanced Soil Mechanics CRC Press New York NYUSA 2013
[25] M J Griffin Handbook of Human Vibration Academic PressNew York NY USA 2012
[26] J Garnier C Gaudin S M Springman P J Culligan DJ Goodings and D Konig ldquoCatalogue of scaling laws andsimilitude questions in geotechnical centrifuge modellingrdquoInternational Journal of Physical Modelling in Geotechnics vol7 no 3 pp 1ndash23 2007
[27] A Fluent 120 Userrsquos Guide User Inputs for PorousMedia 2009
International Journal of
AerospaceEngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
RoboticsJournal of
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Active and Passive Electronic Components
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Journal ofEngineeringVolume 2014
Submit your manuscripts athttpwwwhindawicom
VLSI Design
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Shock and Vibration
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Civil EngineeringAdvances in
Acoustics and VibrationAdvances in
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Electrical and Computer Engineering
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Advances inOptoElectronics
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Volume 2014
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
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Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Modelling amp Simulation in EngineeringHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Chemical EngineeringInternational Journal of Antennas and
Propagation
International Journal of
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Navigation and Observation
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
DistributedSensor Networks
International Journal of
8 Shock and Vibration
Nodal solutionStep = 1
UX (Avg)RSYS = 0
DMX = 0288E minus 03
SMX = 0271E minus 04
Sub = 1X
Y
Z
MN
MX
minus0271E
minus04
minus0210E
minus04
minus0150E
minus04
minus0902Eminus05
minus0301Eminus05
0301Eminus05
0902Eminus05
0150E
minus04
0210E
minus04
0271E
minus04
SMN = minus0271E minus 04
Freq = 0229855
(a)
Nodal solutionStep = 1
Sub = 1
UY (Avg)RSYS = 0
DMX = 0288E minus 03
SMX = 0126E minus 03
X
Y
Z
MN
MX
minus0971E
minus04
minus0125E
minus03
minus0692E
minus04
minus0413Eminus04
minus0134Eminus04
0145Eminus04
0423E
minus04
0702E
minus04
0981E
minus04
0126E
minus03
SMN = minus0125E minus 03
Freq = 0229855
(b)
X
Y
Z MN
MX
0
0287E
minus04
0575E
minus04
0862Eminus04
0115Eminus03
0144Eminus03
0172Eminus03
0201E
minus03
0230E
minus03
0259E
minus03
Nodal solutionStep = 1
UZ (Avg)RSYS = 0
DMX = 0288E minus 03
SMX = 0259E minus 03
Sub = 1
Freq = 0229855
(c)
X
Y
Z
MX0
0320E
minus04
0639E
minus04
0959Eminus04
0128Eminus03
0160Eminus03
0192Eminus03
0224E
minus03
0256E
minus03
0288E
minus03
Nodal solutionStep = 1
Sub = 1
USUM (Avg)RSYS = 0
DMX = 0288E minus 03
SMX = 0288E minus 03
MN
Freq = 0229855
(d)
Figure 16 Mode shape 1 (a) horizontal displacement (b) vertical displacement (c) lateral displacement and (d) total displacement
In soil mechanics the vertical effective stress 1205901015840 forexample is typically calculated by
1205901015840
= 120590119905
minus 119906 (4)
where 120590119905 and 119906 are total stress and pore pressure respectivelyFor a uniform layer with no pore pressure the total verticalstress at a depth119867may be calculated by
120590119905
= 120588119892119867 (5)
where 120588 represents the density of the layer and 119892 representsgravity In the conventional form of centrifugemodeling [26]it is typical that the same materials are used in the model andprototype therefore the densities are the same in model andprototype that is
120588lowast
= 1 (6)
Furthermore in conventional centrifugemodeling all lengthsare scaled by the same factor 119871lowast To produce the same stressin the model as in the prototype we thus require
120588lowast
119892lowast
119867lowast
= 1119892lowast
119871lowast
= 1 (7)
It may be rewritten as
119892lowast
=1
119871lowast
(8)
The above scaling law states that if lengths in the model arereduced by some factor 119899 then gravitational accelerationsmust be increased by the same factor 119899 in order to preserveequal stresses in model and prototype
Shock and Vibration 9
1650
950
500 5200 500
1000
1000785
Laterite
Water
Sand
(a)
1650
950
500 5200 500
1000
1000785
Laterite
Water
Sand
(b)
1650
950
500 5200 500
1000
1000785
Laterite
Water
Sand
(c)
1650
950
500 5200 500
1000
1000785 Water
Sand
Laterite reinforced
(d)
1650
950
1000
1000785
Laterite
Water
Sand
500 5200 500
(e)
Figure 17 Model introducing ((a) (b) (c) (d) and (e)) for small dam (cm) (119878 = 1100)
For dynamic problems where gravity and accelerationsare important all accelerations must scale as gravity is scaledthat is
119886lowast
= 119892lowast
=1
119871lowast
(9)
Since acceleration has units of 1198711198792 it is required that
119886lowast
=119871lowast
1198792
(10)
Hence it is required that
1
119871lowast
=119871lowast
1198792
or 119879lowast
= 119871lowast
(11)
Frequency has units of inverse of time and velocity has unitsof length per time so for dynamic problems we also obtain
119891lowast
=1
119871lowast
Vlowast =119871lowast
119879lowast
= 1 (12)
For model tests involving dynamics the conflict in time scalefactors may be resolved by scaling the permeability of the soil[26]
35 Free Vibration Analysis In dynamic assessment freevibration analysis is the base of study In fact the distributionof frequency in the different vibrationmode can be computedby the application of modal analysis based on finite-elementmethod (FEM) It is worth mentioning that this analysis isperfectly related to the mass and spring In case of the mass-spring-damper system the first assumption is negligibleabout damping effect Therefore there is not any externalforce on mass in this state The force applied to the massby the spring is proportional to the amount of the springthat is stretched ldquo119909rdquo (it can be assumed that spring isalready compressed due to the weight of the mass) Theproportionality constant (119896) is spring stiffness (see Figure 14)The unit measurement is force divided by distance (kgm)
10 Shock and Vibration
(a) (b)
(c) (d)
Figure 18 Small scale dam (a) Dam perspective with two LVDT (b) soil compaction with roller (c) dam section with index network and(d) dam with tank before vibration
The negative sign indicates that force is always opposingthe motion of the mass attached to it according to thefollowing equation
119865119904
= minus119896119909 (13)
The force generated by the mass is proportional to theacceleration of the mass as given by Newtonrsquos second law ofmotion
sum119865 = 119898119886 = 119898 = 1198981198892
119909
1198891199052
(14)
The sumof the forces on themass then generates this ordinarydifferential equation
119898 + 119896119909 = 0 (15)
Assuming that the initial vibration can be started by stretch-ing and releasing the spring with distance (119860) the solution tothe above equation that describes the motion of mass can beseen in the following equation
119909 (119905) = 119860 cos (2120587119891119899
119905) (16)
This solution shows that it will oscillate with simple harmonicmotion that has amplitude of (119860) and a frequency (119891
119899
) Thenumber (119891
119899
) is called the undamped natural frequency Forthe simple mass-spring system frequency is given by
119891119899
=1
2120587
radic119896
119898 (17)
However the relation between frequency and vibrationperiod is always reverse Consider
119879 =1
119891 (18)
In terms of the measurement unit the vibration periodand frequency were according to seconds and hertz It isworth noting that the dominant frequency is the minimumfrequency to produce maximum vibration period
4 Numerical Analysis
In terms of numerical analysismodal analysis was carried outby using ANSYS program in this study to compute dominantfrequency for small scale model regarding 3D analysis Thisprogram is one of the famous software programs with respectto finite-elementmethod (FEM) In particular this software isone of the universal programs with high level of the ability fordifferent analyses A strong ability to compute free vibrationanalysis is possible with modal analysis [27]
41 Elements and Meshing Process To select element basedon Help menu solid 8 nodes 183 (3D) were used for thispurpose Figure 15 shows the mapped mesh for numericalmodeling In this figure 23956 elements and 35457 nodes inmodels were used for free vibration analysis According tothis condition free vibration analysis to access frequency indifferent vibration modes was carried out as results can bediscussed in the next section
Shock and Vibration 11
0 20 40 60 80 100 1200
minus01
minus02
minus03
minus04
minus05
minus06
62 minus029
90 minus048
Time (s)
Disp
lace
men
t (m
m)
Time (s)0 10 20 30 40 50 60 70 80 90 100 110 120
03
025
02
015
01
005
0
Rela
tive
disp
lace
men
t (m
m)
96 024
Model A
0 20 40 60 80 100 120
Time (s)
Disp
lace
men
t (m
m) 2
15
1
05
0
minus05
minus1
minus15
84 15
104 minus064
Time (s)0 10 20 30 40 50 60 70 80 90 100 110 120
Rela
tive
disp
lace
men
t (m
m) 25
2
15
1
05
0
minus05
minus1
104 213
Model B
0 20 40 60 80 100 120
Time (s)
Disp
lace
men
t (m
m)
01201008006004002
0minus002minus004
108 01
108 006
Time (s)
0 10 20 30 40 50 60 70 80 90 100 110 120
Rela
tive
disp
lace
men
t (m
m)
007
006
005
004
003
002
001
0
8 006
Model C
Time (s)0 10 20 30 40 50 60 70 80 90 100 110 120
Rela
tive
disp
lace
men
t (m
m)
0201501005
0minus005minus01minus015minus02
90 017
26 minus017
0 20 40 60 80 100 120
Time (s)
Disp
lace
men
t (m
m) 015
01005
0
minus01minus015
minus005
minus02minus025
114 minus007116 minus022
Model DTime (s)
Disp
lace
men
t (m
m)
01
0
minus01
minus02
minus03
minus04
104 minus011
102 minus033
0 20 40 60 80 100 120
Up streamDown stream
Time (s)
0 10 20 30 40 50 60 70 80 90 100 110 120
Rela
tive
disp
lace
men
t (m
m)
03
025
02
015
01
0
005
86 025
Model E
Figure 19 Vertical displacement in both edges of the crest in models with relative displacement
12 Shock and Vibration
(a) (b) (c)
Figure 20 Damage in the first model (Model A)
(a) (b)
(c) (d)
Figure 21 Damage in the second model (Model B)
42 Free Vibration Analysis and Dominant Frequency Interms of modal analysis the free vibration analysis was cal-culated by ANSYS program Figure 16 shows displacement inthree directions of model and total displacement in the firstvibration mode because based on distribution of frequencyin the first mode to fifth mode it is important to note thatthe minimum frequency (022986Hz) was observed in thefirst vibration mode It means that the vibration period wasmaximum and critical in this mode
Distribution of frequency in different vibration modesindicated that this value was respectively obtained at026257Hz 028387Hz and 030135Hz in the vibration shapemodes 2 to 4
5 Results and Discussion Based on PhysicalSmall Scale Modeling
In order to find the best location of reinforcement in damfive small dams with different locations of reinforcementusing IDL material were vibrated by dominant frequency
(22986Hz) with respect to resonance condition Figure 17shows five small scale dams (Models (a) (b) (c) and (d))it is obvious that models have the same dimension In thisfigure the reinforced area was illustrated with a hatch areaFor example Model (d) indicated that all dam body wasreinforced For this purpose one steel box for modeling wasused This box made by five sheets of Plexiglas with 20mmthickness One of them was in the base of model The levelof reservoir was 75 of the dam height The scale parameterwas 1100 Itmeans thatmodel was one hundred times smallerthan prototypeThedamheightwas 227meter in reality but itwas made 227 cm in physical model In addition small scalemodeling was coupled by foundation Foundation materialwas dense sand with 75 relative density Sand propertieswere mentioned in soil mechanic test Figure 18 shows somedetails including dam perspective soil compaction networkindex and reservoir In this Figure two LVDT on the middleof model at the both edges of the crest were installed Inorder to achieve support one steel frame and one steel beamwere applied (see Figure 18(a)) However both LVDT wereconnected to data logger device by specific cables In terms
Shock and Vibration 13
(a) (b)
Figure 22 Damage in the third model (Model C)
of compaction soil for each layer the steel roller used wasselected by trial error methodWoodmolding with respect tocontrol slope via network index was used In order to avoidabsorption of soil water content both the described moldswere just soaked by water before use For tank purpose smallscale models were filled up by water with very slow rate
After vibration equal to two minutes for all modelsthe vertical displacement for both slopes such as upstreamand downstream were printed With respect to use of Excelprogram Figure 19 shows the distribution of vertical displace-ment in both edges in the middle of the crest and relativedisplacement in all models It was obvious that distributionof the vertical displacement indicated a same trend for bothmodels such as A and E In both models displacement valueswere negative during the vibration It means that both ofthem were in uplift condition In this figure also maximumandminimum peak of the relative displacement respectivelyoccurred in Models B and C with 213mm and 006mm It isalso worth noting that this value was at convergence positionfor Models A and E with 024mm and 025mm respectively
In terms of damage location in models Figure 20 showsthe damage in Model A which occurred at upstream anddownstream The level of damage was greater in upstream Itwas very sensible occurrence in case of hydrodynamic pres-sure along the vibration Also in this figure the maximumlongitudes cracks (see line C) were observed near to themiddle of dam at the crest For damage at downstream thetransverse cracks significantly occurred in dam toe
Figure 21 shows Model B that was damaged after vibra-tion It can be observed that dam was significantly damagedin some locations such as crest and surfaces Body cracks andfailure process dramatically occurred in both areas near toabutments Also in this figure one transverse crack in themiddle of the crest was seen (see Figure 20(c)) This damagewas significantly repeated at upstream in Model C but itwas placed in dam toe and it can be seen in Figure 22 Inaddition Model D was damaged in three places such as bothabutments and the middle of the upstream Figure 23 showsModel D that was damaged in toe Briefly all four modelswere damaged as discussed previously On the other handa successful way in order to remove damage was obtained inModel E as shown in Figure 24 Figure 24 shows that model
Figure 23 Damage in the fourth model (Model D)
was safe after vibration without any damage In this figurethe reinforced blanket layer using IDLmaterial was indicatedby red circles between dam and foundation In addition itwas very important to note that both surfaces were safe anddam was stable under severe seismic loading like resonancemotion In fact a good absorption of energy with respectto increase of damping was found by using IDL In case ofusing this technique displacement in both edges of the crestwith negative value indicated the uplift situation Moreoverrelative displacement was like the first model Thereforedam behavior before and after reinforcement was similar forboth distributions of displacement Nevertheless Model Ewas successful to remove damage with respect to high levelof damping in blanket layer In fact this model shows theexcellent performance in earth dams when the blanket layerwas expanded below tank
Finally blanket layer using isolator damper layer (IDL)below dam and tank is a good recommendation for earthdams in seismic zonewhen reinforced thickness is one-fourthof damheight As recommended optimization of thickness inthis method is the next study
6 Conclusion
In this study the earth dam performance under severeseismic motion such as resonance was evaluated by usingblanket layer (IDL) With respect to soil mechanic testthe optimum mixture for IDL was designed IDL powderwas made by using some materials Main material was alocal soil (laterite) with 90 and additives such as TDA
14 Shock and Vibration
(a) (b)
(c) (d)
Figure 24 Dam stabilization in the fifth model (Model E)
(tire derived aggregate with 7) and MS (microsilica) with3 were used This material was utilized to reinforce damin small scale physical modeling According to numericalanalysis the dominant frequency (02298Hz) in order tohave maximum effect for modeling vibration was computedBy using this frequency for physical modeling the damagelocation and distribution of vertical displacement at bothedges of the crest in the middle of small dams for five smallmodel with scale 1100 were discussed As results the bestperformance in order to remove damages was obviouslyobserved in Model E while other models were dramaticallydamaged in some locations such as upstream downstreamand crest In addition the thickness of blanket layer in thismodel was one-fourth of dam height Finally this model is anovel method to reinforce dam under strong earthquake likeresonance phenomena recommended for earth dam designin seismic zone
Conflict of Interests
The authors declare that there is no conflict of interestsregarding the publication of this paper
Acknowledgment
This study ismade possible by the support of the InternationalDoctorate Fellowship of Universiti Teknologi Malaysia andit is very much appreciated
References
[1] M Zeghal and A M Abdel-Ghaffar ldquoAnalysis of behavior ofearth dam using strong-motion earthquakes recordsrdquo Journalof Geotechnical Engineering vol 118 no 2 pp 266ndash277 1992
[2] V Gikas andM Sakellariou ldquoSettlement analysis of theMornosearth dam (Greece) evidence from numerical modeling andgeodetic monitoringrdquo Engineering Structures vol 30 no 11 pp3074ndash3081 2008
[3] R Verdugo N Sitar J D Frost et al ldquoSeismic performanceof earth structures during the February 2010 Maule Chileearthquake dams levees tailings dams and retaining wallsrdquoEarthquake Spectra vol 28 no 1 pp S75ndashS96 2012
[4] Y Parish and F N Abadi ldquoDynamic behaviour of earth damsfor variation of earth material stiffnessrdquo Proceedings of WorldAcademy of Science Engineering and Technology vol 50 pp606ndash611 2009
[5] T G Berhe X T Wang and W Wu ldquoNumerical investigationinto the arrangement of clay core on the seismic performanceof earth damsrdquo in Proceedings of the GeoShanghai InternationalConference on Soil Dynamics and Earthquake Engineering pp131ndash138 ASCE June 2010
[6] Z F Xia G L Ye J HWang B Ye and F Zhang ldquoFully couplednumerical analysis of repeated shake-consolidation process ofearth embankment on liquefiable foundationrdquo Soil Dynamicsand Earthquake Engineering vol 30 no 11 pp 1309ndash1318 2010
[7] X J Kong Y Zhou B Xu and D G Zou ldquoAnalysis on seismicfailure mechanism of Zipingpu dam and several reflections ofaseismic design for high rock-fill damrdquo in Proceedings of theEarth and Space pp 3177ndash3189 March 2010
Shock and Vibration 15
[8] A BayraktarM E Kartal and S Adanur ldquoThe effect of concreteslabrockfill interface behavior on the earthquake performanceof a CFR damrdquo International Journal of Non-Linear Mechanicsvol 46 no 1 pp 35ndash46 2011
[9] R P Piao A H Rippe B Myers and K W Lane ldquoEarthdam liquefaction and deformation analysis using numericalmodelingrdquo in Proceedings of the GeoCongress pp 1ndash6 March2006
[10] A W Elgamal ldquoThree-dimensional seismic analysis of la villitadamrdquo Journal of Geotechnical Engineering vol 118 no 12 pp1937ndash1958 1992
[11] B Gordan and B A Azlan ldquoEffect of material properties inCFRD tailing-embankment bridge during a strong earthquakerdquoCaspian Journal of Applied Sciences Research vol 2 no 11 pp61ndash72 2013
[12] A Papalou and J Bielak ldquoSeismic elastic response of Earthdams with canyon interactionrdquo Journal of Geotechnical andGeoenvironmental Engineering vol 127 no 5 pp 446ndash453 2001
[13] Y Yu L Xie and B Zhang ldquoStability of earth-rockfill damsinfluence of geometry on the three-dimensional effectrdquo Com-puters and Geotechnics vol 32 no 5 pp 326ndash339 2005
[14] L H Mejia and H B Seed ldquoComparison of 2-D and 3-D dynamic analyses of earth damsrdquo Journal of GeotechnicalEngineering vol 109 no 11 pp 1383ndash1398 1983
[15] J L Borges ldquoThree-dimensional analysis of embankmentson soft soils incorporating vertical drains by finite elementmethodrdquoComputers andGeotechnics vol 31 no 8 pp 665ndash6762004
[16] A Yildiz ldquoNumerical analyses of embankments on PVDimproved soft claysrdquo Advances in Engineering Software vol 40no 10 pp 1047ndash1055 2009
[17] B Le Hello and P Villard ldquoEmbankments reinforced by pilesand geosynthetics-Numerical and experimental studies dealingwith the transfer of load on the soil embankmentrdquo EngineeringGeology vol 106 no 1-2 pp 78ndash91 2009
[18] S W Abusharar J J Zheng B G Chen and J H Yin ldquoA sim-plified method for analysis of a piled embankment reinforcedwith geosyntheticsrdquo Geotextiles and Geomembranes vol 27 no1 pp 39ndash52 2009
[19] R Noorzad and M Omidvar ldquoSeismic displacement analysisof embankment dams with reinforced cohesive shellrdquo SoilDynamics and Earthquake Engineering vol 30 no 11 pp 1149ndash1157 2010
[20] T Matsumaru K Watanabe and J Isono ldquoApplication ofcement-mixed gravel reinforced by ground for soft groundimprovementrdquo in Proceedings of the 4th Asian Regional Confer-ence on Geosynthetics pp 380ndash385 Shanghai China June 2008
[21] Namdar and A A K Pelko ldquoSeismic evaluation of embank-ment shaking table test and finite element methodrdquo ThePacific Journal of Science and Technology vol 11 no 2 2010httpwwwakamaiuniversityusPJST
[22] L Wang G Zhang and J Zhang ldquoCentrifuge model tests ofgeotextile-reinforced soil embankments during an earthquakerdquoGeotextiles and Geomembranes vol 29 no 3 pp 222ndash232 2011
[23] H B Seed R T Wong I M Idriss and K Tokimatsu ldquoModuliand damping factors for dynamic analyses of cohesionless soilsrdquoJournal of Geotechnical Engineering vol 112 no 11 pp 1016ndash1032 1986
[24] B M Das Advanced Soil Mechanics CRC Press New York NYUSA 2013
[25] M J Griffin Handbook of Human Vibration Academic PressNew York NY USA 2012
[26] J Garnier C Gaudin S M Springman P J Culligan DJ Goodings and D Konig ldquoCatalogue of scaling laws andsimilitude questions in geotechnical centrifuge modellingrdquoInternational Journal of Physical Modelling in Geotechnics vol7 no 3 pp 1ndash23 2007
[27] A Fluent 120 Userrsquos Guide User Inputs for PorousMedia 2009
International Journal of
AerospaceEngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
RoboticsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Active and Passive Electronic Components
Control Scienceand Engineering
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
International Journal of
RotatingMachinery
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporation httpwwwhindawicom
Journal ofEngineeringVolume 2014
Submit your manuscripts athttpwwwhindawicom
VLSI Design
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Shock and Vibration
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Civil EngineeringAdvances in
Acoustics and VibrationAdvances in
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Electrical and Computer Engineering
Journal of
Advances inOptoElectronics
Hindawi Publishing Corporation httpwwwhindawicom
Volume 2014
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
SensorsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Modelling amp Simulation in EngineeringHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Chemical EngineeringInternational Journal of Antennas and
Propagation
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Navigation and Observation
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
DistributedSensor Networks
International Journal of
Shock and Vibration 9
1650
950
500 5200 500
1000
1000785
Laterite
Water
Sand
(a)
1650
950
500 5200 500
1000
1000785
Laterite
Water
Sand
(b)
1650
950
500 5200 500
1000
1000785
Laterite
Water
Sand
(c)
1650
950
500 5200 500
1000
1000785 Water
Sand
Laterite reinforced
(d)
1650
950
1000
1000785
Laterite
Water
Sand
500 5200 500
(e)
Figure 17 Model introducing ((a) (b) (c) (d) and (e)) for small dam (cm) (119878 = 1100)
For dynamic problems where gravity and accelerationsare important all accelerations must scale as gravity is scaledthat is
119886lowast
= 119892lowast
=1
119871lowast
(9)
Since acceleration has units of 1198711198792 it is required that
119886lowast
=119871lowast
1198792
(10)
Hence it is required that
1
119871lowast
=119871lowast
1198792
or 119879lowast
= 119871lowast
(11)
Frequency has units of inverse of time and velocity has unitsof length per time so for dynamic problems we also obtain
119891lowast
=1
119871lowast
Vlowast =119871lowast
119879lowast
= 1 (12)
For model tests involving dynamics the conflict in time scalefactors may be resolved by scaling the permeability of the soil[26]
35 Free Vibration Analysis In dynamic assessment freevibration analysis is the base of study In fact the distributionof frequency in the different vibrationmode can be computedby the application of modal analysis based on finite-elementmethod (FEM) It is worth mentioning that this analysis isperfectly related to the mass and spring In case of the mass-spring-damper system the first assumption is negligibleabout damping effect Therefore there is not any externalforce on mass in this state The force applied to the massby the spring is proportional to the amount of the springthat is stretched ldquo119909rdquo (it can be assumed that spring isalready compressed due to the weight of the mass) Theproportionality constant (119896) is spring stiffness (see Figure 14)The unit measurement is force divided by distance (kgm)
10 Shock and Vibration
(a) (b)
(c) (d)
Figure 18 Small scale dam (a) Dam perspective with two LVDT (b) soil compaction with roller (c) dam section with index network and(d) dam with tank before vibration
The negative sign indicates that force is always opposingthe motion of the mass attached to it according to thefollowing equation
119865119904
= minus119896119909 (13)
The force generated by the mass is proportional to theacceleration of the mass as given by Newtonrsquos second law ofmotion
sum119865 = 119898119886 = 119898 = 1198981198892
119909
1198891199052
(14)
The sumof the forces on themass then generates this ordinarydifferential equation
119898 + 119896119909 = 0 (15)
Assuming that the initial vibration can be started by stretch-ing and releasing the spring with distance (119860) the solution tothe above equation that describes the motion of mass can beseen in the following equation
119909 (119905) = 119860 cos (2120587119891119899
119905) (16)
This solution shows that it will oscillate with simple harmonicmotion that has amplitude of (119860) and a frequency (119891
119899
) Thenumber (119891
119899
) is called the undamped natural frequency Forthe simple mass-spring system frequency is given by
119891119899
=1
2120587
radic119896
119898 (17)
However the relation between frequency and vibrationperiod is always reverse Consider
119879 =1
119891 (18)
In terms of the measurement unit the vibration periodand frequency were according to seconds and hertz It isworth noting that the dominant frequency is the minimumfrequency to produce maximum vibration period
4 Numerical Analysis
In terms of numerical analysismodal analysis was carried outby using ANSYS program in this study to compute dominantfrequency for small scale model regarding 3D analysis Thisprogram is one of the famous software programs with respectto finite-elementmethod (FEM) In particular this software isone of the universal programs with high level of the ability fordifferent analyses A strong ability to compute free vibrationanalysis is possible with modal analysis [27]
41 Elements and Meshing Process To select element basedon Help menu solid 8 nodes 183 (3D) were used for thispurpose Figure 15 shows the mapped mesh for numericalmodeling In this figure 23956 elements and 35457 nodes inmodels were used for free vibration analysis According tothis condition free vibration analysis to access frequency indifferent vibration modes was carried out as results can bediscussed in the next section
Shock and Vibration 11
0 20 40 60 80 100 1200
minus01
minus02
minus03
minus04
minus05
minus06
62 minus029
90 minus048
Time (s)
Disp
lace
men
t (m
m)
Time (s)0 10 20 30 40 50 60 70 80 90 100 110 120
03
025
02
015
01
005
0
Rela
tive
disp
lace
men
t (m
m)
96 024
Model A
0 20 40 60 80 100 120
Time (s)
Disp
lace
men
t (m
m) 2
15
1
05
0
minus05
minus1
minus15
84 15
104 minus064
Time (s)0 10 20 30 40 50 60 70 80 90 100 110 120
Rela
tive
disp
lace
men
t (m
m) 25
2
15
1
05
0
minus05
minus1
104 213
Model B
0 20 40 60 80 100 120
Time (s)
Disp
lace
men
t (m
m)
01201008006004002
0minus002minus004
108 01
108 006
Time (s)
0 10 20 30 40 50 60 70 80 90 100 110 120
Rela
tive
disp
lace
men
t (m
m)
007
006
005
004
003
002
001
0
8 006
Model C
Time (s)0 10 20 30 40 50 60 70 80 90 100 110 120
Rela
tive
disp
lace
men
t (m
m)
0201501005
0minus005minus01minus015minus02
90 017
26 minus017
0 20 40 60 80 100 120
Time (s)
Disp
lace
men
t (m
m) 015
01005
0
minus01minus015
minus005
minus02minus025
114 minus007116 minus022
Model DTime (s)
Disp
lace
men
t (m
m)
01
0
minus01
minus02
minus03
minus04
104 minus011
102 minus033
0 20 40 60 80 100 120
Up streamDown stream
Time (s)
0 10 20 30 40 50 60 70 80 90 100 110 120
Rela
tive
disp
lace
men
t (m
m)
03
025
02
015
01
0
005
86 025
Model E
Figure 19 Vertical displacement in both edges of the crest in models with relative displacement
12 Shock and Vibration
(a) (b) (c)
Figure 20 Damage in the first model (Model A)
(a) (b)
(c) (d)
Figure 21 Damage in the second model (Model B)
42 Free Vibration Analysis and Dominant Frequency Interms of modal analysis the free vibration analysis was cal-culated by ANSYS program Figure 16 shows displacement inthree directions of model and total displacement in the firstvibration mode because based on distribution of frequencyin the first mode to fifth mode it is important to note thatthe minimum frequency (022986Hz) was observed in thefirst vibration mode It means that the vibration period wasmaximum and critical in this mode
Distribution of frequency in different vibration modesindicated that this value was respectively obtained at026257Hz 028387Hz and 030135Hz in the vibration shapemodes 2 to 4
5 Results and Discussion Based on PhysicalSmall Scale Modeling
In order to find the best location of reinforcement in damfive small dams with different locations of reinforcementusing IDL material were vibrated by dominant frequency
(22986Hz) with respect to resonance condition Figure 17shows five small scale dams (Models (a) (b) (c) and (d))it is obvious that models have the same dimension In thisfigure the reinforced area was illustrated with a hatch areaFor example Model (d) indicated that all dam body wasreinforced For this purpose one steel box for modeling wasused This box made by five sheets of Plexiglas with 20mmthickness One of them was in the base of model The levelof reservoir was 75 of the dam height The scale parameterwas 1100 Itmeans thatmodel was one hundred times smallerthan prototypeThedamheightwas 227meter in reality but itwas made 227 cm in physical model In addition small scalemodeling was coupled by foundation Foundation materialwas dense sand with 75 relative density Sand propertieswere mentioned in soil mechanic test Figure 18 shows somedetails including dam perspective soil compaction networkindex and reservoir In this Figure two LVDT on the middleof model at the both edges of the crest were installed Inorder to achieve support one steel frame and one steel beamwere applied (see Figure 18(a)) However both LVDT wereconnected to data logger device by specific cables In terms
Shock and Vibration 13
(a) (b)
Figure 22 Damage in the third model (Model C)
of compaction soil for each layer the steel roller used wasselected by trial error methodWoodmolding with respect tocontrol slope via network index was used In order to avoidabsorption of soil water content both the described moldswere just soaked by water before use For tank purpose smallscale models were filled up by water with very slow rate
After vibration equal to two minutes for all modelsthe vertical displacement for both slopes such as upstreamand downstream were printed With respect to use of Excelprogram Figure 19 shows the distribution of vertical displace-ment in both edges in the middle of the crest and relativedisplacement in all models It was obvious that distributionof the vertical displacement indicated a same trend for bothmodels such as A and E In both models displacement valueswere negative during the vibration It means that both ofthem were in uplift condition In this figure also maximumandminimum peak of the relative displacement respectivelyoccurred in Models B and C with 213mm and 006mm It isalso worth noting that this value was at convergence positionfor Models A and E with 024mm and 025mm respectively
In terms of damage location in models Figure 20 showsthe damage in Model A which occurred at upstream anddownstream The level of damage was greater in upstream Itwas very sensible occurrence in case of hydrodynamic pres-sure along the vibration Also in this figure the maximumlongitudes cracks (see line C) were observed near to themiddle of dam at the crest For damage at downstream thetransverse cracks significantly occurred in dam toe
Figure 21 shows Model B that was damaged after vibra-tion It can be observed that dam was significantly damagedin some locations such as crest and surfaces Body cracks andfailure process dramatically occurred in both areas near toabutments Also in this figure one transverse crack in themiddle of the crest was seen (see Figure 20(c)) This damagewas significantly repeated at upstream in Model C but itwas placed in dam toe and it can be seen in Figure 22 Inaddition Model D was damaged in three places such as bothabutments and the middle of the upstream Figure 23 showsModel D that was damaged in toe Briefly all four modelswere damaged as discussed previously On the other handa successful way in order to remove damage was obtained inModel E as shown in Figure 24 Figure 24 shows that model
Figure 23 Damage in the fourth model (Model D)
was safe after vibration without any damage In this figurethe reinforced blanket layer using IDLmaterial was indicatedby red circles between dam and foundation In addition itwas very important to note that both surfaces were safe anddam was stable under severe seismic loading like resonancemotion In fact a good absorption of energy with respectto increase of damping was found by using IDL In case ofusing this technique displacement in both edges of the crestwith negative value indicated the uplift situation Moreoverrelative displacement was like the first model Thereforedam behavior before and after reinforcement was similar forboth distributions of displacement Nevertheless Model Ewas successful to remove damage with respect to high levelof damping in blanket layer In fact this model shows theexcellent performance in earth dams when the blanket layerwas expanded below tank
Finally blanket layer using isolator damper layer (IDL)below dam and tank is a good recommendation for earthdams in seismic zonewhen reinforced thickness is one-fourthof damheight As recommended optimization of thickness inthis method is the next study
6 Conclusion
In this study the earth dam performance under severeseismic motion such as resonance was evaluated by usingblanket layer (IDL) With respect to soil mechanic testthe optimum mixture for IDL was designed IDL powderwas made by using some materials Main material was alocal soil (laterite) with 90 and additives such as TDA
14 Shock and Vibration
(a) (b)
(c) (d)
Figure 24 Dam stabilization in the fifth model (Model E)
(tire derived aggregate with 7) and MS (microsilica) with3 were used This material was utilized to reinforce damin small scale physical modeling According to numericalanalysis the dominant frequency (02298Hz) in order tohave maximum effect for modeling vibration was computedBy using this frequency for physical modeling the damagelocation and distribution of vertical displacement at bothedges of the crest in the middle of small dams for five smallmodel with scale 1100 were discussed As results the bestperformance in order to remove damages was obviouslyobserved in Model E while other models were dramaticallydamaged in some locations such as upstream downstreamand crest In addition the thickness of blanket layer in thismodel was one-fourth of dam height Finally this model is anovel method to reinforce dam under strong earthquake likeresonance phenomena recommended for earth dam designin seismic zone
Conflict of Interests
The authors declare that there is no conflict of interestsregarding the publication of this paper
Acknowledgment
This study ismade possible by the support of the InternationalDoctorate Fellowship of Universiti Teknologi Malaysia andit is very much appreciated
References
[1] M Zeghal and A M Abdel-Ghaffar ldquoAnalysis of behavior ofearth dam using strong-motion earthquakes recordsrdquo Journalof Geotechnical Engineering vol 118 no 2 pp 266ndash277 1992
[2] V Gikas andM Sakellariou ldquoSettlement analysis of theMornosearth dam (Greece) evidence from numerical modeling andgeodetic monitoringrdquo Engineering Structures vol 30 no 11 pp3074ndash3081 2008
[3] R Verdugo N Sitar J D Frost et al ldquoSeismic performanceof earth structures during the February 2010 Maule Chileearthquake dams levees tailings dams and retaining wallsrdquoEarthquake Spectra vol 28 no 1 pp S75ndashS96 2012
[4] Y Parish and F N Abadi ldquoDynamic behaviour of earth damsfor variation of earth material stiffnessrdquo Proceedings of WorldAcademy of Science Engineering and Technology vol 50 pp606ndash611 2009
[5] T G Berhe X T Wang and W Wu ldquoNumerical investigationinto the arrangement of clay core on the seismic performanceof earth damsrdquo in Proceedings of the GeoShanghai InternationalConference on Soil Dynamics and Earthquake Engineering pp131ndash138 ASCE June 2010
[6] Z F Xia G L Ye J HWang B Ye and F Zhang ldquoFully couplednumerical analysis of repeated shake-consolidation process ofearth embankment on liquefiable foundationrdquo Soil Dynamicsand Earthquake Engineering vol 30 no 11 pp 1309ndash1318 2010
[7] X J Kong Y Zhou B Xu and D G Zou ldquoAnalysis on seismicfailure mechanism of Zipingpu dam and several reflections ofaseismic design for high rock-fill damrdquo in Proceedings of theEarth and Space pp 3177ndash3189 March 2010
Shock and Vibration 15
[8] A BayraktarM E Kartal and S Adanur ldquoThe effect of concreteslabrockfill interface behavior on the earthquake performanceof a CFR damrdquo International Journal of Non-Linear Mechanicsvol 46 no 1 pp 35ndash46 2011
[9] R P Piao A H Rippe B Myers and K W Lane ldquoEarthdam liquefaction and deformation analysis using numericalmodelingrdquo in Proceedings of the GeoCongress pp 1ndash6 March2006
[10] A W Elgamal ldquoThree-dimensional seismic analysis of la villitadamrdquo Journal of Geotechnical Engineering vol 118 no 12 pp1937ndash1958 1992
[11] B Gordan and B A Azlan ldquoEffect of material properties inCFRD tailing-embankment bridge during a strong earthquakerdquoCaspian Journal of Applied Sciences Research vol 2 no 11 pp61ndash72 2013
[12] A Papalou and J Bielak ldquoSeismic elastic response of Earthdams with canyon interactionrdquo Journal of Geotechnical andGeoenvironmental Engineering vol 127 no 5 pp 446ndash453 2001
[13] Y Yu L Xie and B Zhang ldquoStability of earth-rockfill damsinfluence of geometry on the three-dimensional effectrdquo Com-puters and Geotechnics vol 32 no 5 pp 326ndash339 2005
[14] L H Mejia and H B Seed ldquoComparison of 2-D and 3-D dynamic analyses of earth damsrdquo Journal of GeotechnicalEngineering vol 109 no 11 pp 1383ndash1398 1983
[15] J L Borges ldquoThree-dimensional analysis of embankmentson soft soils incorporating vertical drains by finite elementmethodrdquoComputers andGeotechnics vol 31 no 8 pp 665ndash6762004
[16] A Yildiz ldquoNumerical analyses of embankments on PVDimproved soft claysrdquo Advances in Engineering Software vol 40no 10 pp 1047ndash1055 2009
[17] B Le Hello and P Villard ldquoEmbankments reinforced by pilesand geosynthetics-Numerical and experimental studies dealingwith the transfer of load on the soil embankmentrdquo EngineeringGeology vol 106 no 1-2 pp 78ndash91 2009
[18] S W Abusharar J J Zheng B G Chen and J H Yin ldquoA sim-plified method for analysis of a piled embankment reinforcedwith geosyntheticsrdquo Geotextiles and Geomembranes vol 27 no1 pp 39ndash52 2009
[19] R Noorzad and M Omidvar ldquoSeismic displacement analysisof embankment dams with reinforced cohesive shellrdquo SoilDynamics and Earthquake Engineering vol 30 no 11 pp 1149ndash1157 2010
[20] T Matsumaru K Watanabe and J Isono ldquoApplication ofcement-mixed gravel reinforced by ground for soft groundimprovementrdquo in Proceedings of the 4th Asian Regional Confer-ence on Geosynthetics pp 380ndash385 Shanghai China June 2008
[21] Namdar and A A K Pelko ldquoSeismic evaluation of embank-ment shaking table test and finite element methodrdquo ThePacific Journal of Science and Technology vol 11 no 2 2010httpwwwakamaiuniversityusPJST
[22] L Wang G Zhang and J Zhang ldquoCentrifuge model tests ofgeotextile-reinforced soil embankments during an earthquakerdquoGeotextiles and Geomembranes vol 29 no 3 pp 222ndash232 2011
[23] H B Seed R T Wong I M Idriss and K Tokimatsu ldquoModuliand damping factors for dynamic analyses of cohesionless soilsrdquoJournal of Geotechnical Engineering vol 112 no 11 pp 1016ndash1032 1986
[24] B M Das Advanced Soil Mechanics CRC Press New York NYUSA 2013
[25] M J Griffin Handbook of Human Vibration Academic PressNew York NY USA 2012
[26] J Garnier C Gaudin S M Springman P J Culligan DJ Goodings and D Konig ldquoCatalogue of scaling laws andsimilitude questions in geotechnical centrifuge modellingrdquoInternational Journal of Physical Modelling in Geotechnics vol7 no 3 pp 1ndash23 2007
[27] A Fluent 120 Userrsquos Guide User Inputs for PorousMedia 2009
International Journal of
AerospaceEngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
RoboticsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Active and Passive Electronic Components
Control Scienceand Engineering
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
International Journal of
RotatingMachinery
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporation httpwwwhindawicom
Journal ofEngineeringVolume 2014
Submit your manuscripts athttpwwwhindawicom
VLSI Design
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Shock and Vibration
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Civil EngineeringAdvances in
Acoustics and VibrationAdvances in
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Electrical and Computer Engineering
Journal of
Advances inOptoElectronics
Hindawi Publishing Corporation httpwwwhindawicom
Volume 2014
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
SensorsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Modelling amp Simulation in EngineeringHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Chemical EngineeringInternational Journal of Antennas and
Propagation
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Navigation and Observation
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
DistributedSensor Networks
International Journal of
10 Shock and Vibration
(a) (b)
(c) (d)
Figure 18 Small scale dam (a) Dam perspective with two LVDT (b) soil compaction with roller (c) dam section with index network and(d) dam with tank before vibration
The negative sign indicates that force is always opposingthe motion of the mass attached to it according to thefollowing equation
119865119904
= minus119896119909 (13)
The force generated by the mass is proportional to theacceleration of the mass as given by Newtonrsquos second law ofmotion
sum119865 = 119898119886 = 119898 = 1198981198892
119909
1198891199052
(14)
The sumof the forces on themass then generates this ordinarydifferential equation
119898 + 119896119909 = 0 (15)
Assuming that the initial vibration can be started by stretch-ing and releasing the spring with distance (119860) the solution tothe above equation that describes the motion of mass can beseen in the following equation
119909 (119905) = 119860 cos (2120587119891119899
119905) (16)
This solution shows that it will oscillate with simple harmonicmotion that has amplitude of (119860) and a frequency (119891
119899
) Thenumber (119891
119899
) is called the undamped natural frequency Forthe simple mass-spring system frequency is given by
119891119899
=1
2120587
radic119896
119898 (17)
However the relation between frequency and vibrationperiod is always reverse Consider
119879 =1
119891 (18)
In terms of the measurement unit the vibration periodand frequency were according to seconds and hertz It isworth noting that the dominant frequency is the minimumfrequency to produce maximum vibration period
4 Numerical Analysis
In terms of numerical analysismodal analysis was carried outby using ANSYS program in this study to compute dominantfrequency for small scale model regarding 3D analysis Thisprogram is one of the famous software programs with respectto finite-elementmethod (FEM) In particular this software isone of the universal programs with high level of the ability fordifferent analyses A strong ability to compute free vibrationanalysis is possible with modal analysis [27]
41 Elements and Meshing Process To select element basedon Help menu solid 8 nodes 183 (3D) were used for thispurpose Figure 15 shows the mapped mesh for numericalmodeling In this figure 23956 elements and 35457 nodes inmodels were used for free vibration analysis According tothis condition free vibration analysis to access frequency indifferent vibration modes was carried out as results can bediscussed in the next section
Shock and Vibration 11
0 20 40 60 80 100 1200
minus01
minus02
minus03
minus04
minus05
minus06
62 minus029
90 minus048
Time (s)
Disp
lace
men
t (m
m)
Time (s)0 10 20 30 40 50 60 70 80 90 100 110 120
03
025
02
015
01
005
0
Rela
tive
disp
lace
men
t (m
m)
96 024
Model A
0 20 40 60 80 100 120
Time (s)
Disp
lace
men
t (m
m) 2
15
1
05
0
minus05
minus1
minus15
84 15
104 minus064
Time (s)0 10 20 30 40 50 60 70 80 90 100 110 120
Rela
tive
disp
lace
men
t (m
m) 25
2
15
1
05
0
minus05
minus1
104 213
Model B
0 20 40 60 80 100 120
Time (s)
Disp
lace
men
t (m
m)
01201008006004002
0minus002minus004
108 01
108 006
Time (s)
0 10 20 30 40 50 60 70 80 90 100 110 120
Rela
tive
disp
lace
men
t (m
m)
007
006
005
004
003
002
001
0
8 006
Model C
Time (s)0 10 20 30 40 50 60 70 80 90 100 110 120
Rela
tive
disp
lace
men
t (m
m)
0201501005
0minus005minus01minus015minus02
90 017
26 minus017
0 20 40 60 80 100 120
Time (s)
Disp
lace
men
t (m
m) 015
01005
0
minus01minus015
minus005
minus02minus025
114 minus007116 minus022
Model DTime (s)
Disp
lace
men
t (m
m)
01
0
minus01
minus02
minus03
minus04
104 minus011
102 minus033
0 20 40 60 80 100 120
Up streamDown stream
Time (s)
0 10 20 30 40 50 60 70 80 90 100 110 120
Rela
tive
disp
lace
men
t (m
m)
03
025
02
015
01
0
005
86 025
Model E
Figure 19 Vertical displacement in both edges of the crest in models with relative displacement
12 Shock and Vibration
(a) (b) (c)
Figure 20 Damage in the first model (Model A)
(a) (b)
(c) (d)
Figure 21 Damage in the second model (Model B)
42 Free Vibration Analysis and Dominant Frequency Interms of modal analysis the free vibration analysis was cal-culated by ANSYS program Figure 16 shows displacement inthree directions of model and total displacement in the firstvibration mode because based on distribution of frequencyin the first mode to fifth mode it is important to note thatthe minimum frequency (022986Hz) was observed in thefirst vibration mode It means that the vibration period wasmaximum and critical in this mode
Distribution of frequency in different vibration modesindicated that this value was respectively obtained at026257Hz 028387Hz and 030135Hz in the vibration shapemodes 2 to 4
5 Results and Discussion Based on PhysicalSmall Scale Modeling
In order to find the best location of reinforcement in damfive small dams with different locations of reinforcementusing IDL material were vibrated by dominant frequency
(22986Hz) with respect to resonance condition Figure 17shows five small scale dams (Models (a) (b) (c) and (d))it is obvious that models have the same dimension In thisfigure the reinforced area was illustrated with a hatch areaFor example Model (d) indicated that all dam body wasreinforced For this purpose one steel box for modeling wasused This box made by five sheets of Plexiglas with 20mmthickness One of them was in the base of model The levelof reservoir was 75 of the dam height The scale parameterwas 1100 Itmeans thatmodel was one hundred times smallerthan prototypeThedamheightwas 227meter in reality but itwas made 227 cm in physical model In addition small scalemodeling was coupled by foundation Foundation materialwas dense sand with 75 relative density Sand propertieswere mentioned in soil mechanic test Figure 18 shows somedetails including dam perspective soil compaction networkindex and reservoir In this Figure two LVDT on the middleof model at the both edges of the crest were installed Inorder to achieve support one steel frame and one steel beamwere applied (see Figure 18(a)) However both LVDT wereconnected to data logger device by specific cables In terms
Shock and Vibration 13
(a) (b)
Figure 22 Damage in the third model (Model C)
of compaction soil for each layer the steel roller used wasselected by trial error methodWoodmolding with respect tocontrol slope via network index was used In order to avoidabsorption of soil water content both the described moldswere just soaked by water before use For tank purpose smallscale models were filled up by water with very slow rate
After vibration equal to two minutes for all modelsthe vertical displacement for both slopes such as upstreamand downstream were printed With respect to use of Excelprogram Figure 19 shows the distribution of vertical displace-ment in both edges in the middle of the crest and relativedisplacement in all models It was obvious that distributionof the vertical displacement indicated a same trend for bothmodels such as A and E In both models displacement valueswere negative during the vibration It means that both ofthem were in uplift condition In this figure also maximumandminimum peak of the relative displacement respectivelyoccurred in Models B and C with 213mm and 006mm It isalso worth noting that this value was at convergence positionfor Models A and E with 024mm and 025mm respectively
In terms of damage location in models Figure 20 showsthe damage in Model A which occurred at upstream anddownstream The level of damage was greater in upstream Itwas very sensible occurrence in case of hydrodynamic pres-sure along the vibration Also in this figure the maximumlongitudes cracks (see line C) were observed near to themiddle of dam at the crest For damage at downstream thetransverse cracks significantly occurred in dam toe
Figure 21 shows Model B that was damaged after vibra-tion It can be observed that dam was significantly damagedin some locations such as crest and surfaces Body cracks andfailure process dramatically occurred in both areas near toabutments Also in this figure one transverse crack in themiddle of the crest was seen (see Figure 20(c)) This damagewas significantly repeated at upstream in Model C but itwas placed in dam toe and it can be seen in Figure 22 Inaddition Model D was damaged in three places such as bothabutments and the middle of the upstream Figure 23 showsModel D that was damaged in toe Briefly all four modelswere damaged as discussed previously On the other handa successful way in order to remove damage was obtained inModel E as shown in Figure 24 Figure 24 shows that model
Figure 23 Damage in the fourth model (Model D)
was safe after vibration without any damage In this figurethe reinforced blanket layer using IDLmaterial was indicatedby red circles between dam and foundation In addition itwas very important to note that both surfaces were safe anddam was stable under severe seismic loading like resonancemotion In fact a good absorption of energy with respectto increase of damping was found by using IDL In case ofusing this technique displacement in both edges of the crestwith negative value indicated the uplift situation Moreoverrelative displacement was like the first model Thereforedam behavior before and after reinforcement was similar forboth distributions of displacement Nevertheless Model Ewas successful to remove damage with respect to high levelof damping in blanket layer In fact this model shows theexcellent performance in earth dams when the blanket layerwas expanded below tank
Finally blanket layer using isolator damper layer (IDL)below dam and tank is a good recommendation for earthdams in seismic zonewhen reinforced thickness is one-fourthof damheight As recommended optimization of thickness inthis method is the next study
6 Conclusion
In this study the earth dam performance under severeseismic motion such as resonance was evaluated by usingblanket layer (IDL) With respect to soil mechanic testthe optimum mixture for IDL was designed IDL powderwas made by using some materials Main material was alocal soil (laterite) with 90 and additives such as TDA
14 Shock and Vibration
(a) (b)
(c) (d)
Figure 24 Dam stabilization in the fifth model (Model E)
(tire derived aggregate with 7) and MS (microsilica) with3 were used This material was utilized to reinforce damin small scale physical modeling According to numericalanalysis the dominant frequency (02298Hz) in order tohave maximum effect for modeling vibration was computedBy using this frequency for physical modeling the damagelocation and distribution of vertical displacement at bothedges of the crest in the middle of small dams for five smallmodel with scale 1100 were discussed As results the bestperformance in order to remove damages was obviouslyobserved in Model E while other models were dramaticallydamaged in some locations such as upstream downstreamand crest In addition the thickness of blanket layer in thismodel was one-fourth of dam height Finally this model is anovel method to reinforce dam under strong earthquake likeresonance phenomena recommended for earth dam designin seismic zone
Conflict of Interests
The authors declare that there is no conflict of interestsregarding the publication of this paper
Acknowledgment
This study ismade possible by the support of the InternationalDoctorate Fellowship of Universiti Teknologi Malaysia andit is very much appreciated
References
[1] M Zeghal and A M Abdel-Ghaffar ldquoAnalysis of behavior ofearth dam using strong-motion earthquakes recordsrdquo Journalof Geotechnical Engineering vol 118 no 2 pp 266ndash277 1992
[2] V Gikas andM Sakellariou ldquoSettlement analysis of theMornosearth dam (Greece) evidence from numerical modeling andgeodetic monitoringrdquo Engineering Structures vol 30 no 11 pp3074ndash3081 2008
[3] R Verdugo N Sitar J D Frost et al ldquoSeismic performanceof earth structures during the February 2010 Maule Chileearthquake dams levees tailings dams and retaining wallsrdquoEarthquake Spectra vol 28 no 1 pp S75ndashS96 2012
[4] Y Parish and F N Abadi ldquoDynamic behaviour of earth damsfor variation of earth material stiffnessrdquo Proceedings of WorldAcademy of Science Engineering and Technology vol 50 pp606ndash611 2009
[5] T G Berhe X T Wang and W Wu ldquoNumerical investigationinto the arrangement of clay core on the seismic performanceof earth damsrdquo in Proceedings of the GeoShanghai InternationalConference on Soil Dynamics and Earthquake Engineering pp131ndash138 ASCE June 2010
[6] Z F Xia G L Ye J HWang B Ye and F Zhang ldquoFully couplednumerical analysis of repeated shake-consolidation process ofearth embankment on liquefiable foundationrdquo Soil Dynamicsand Earthquake Engineering vol 30 no 11 pp 1309ndash1318 2010
[7] X J Kong Y Zhou B Xu and D G Zou ldquoAnalysis on seismicfailure mechanism of Zipingpu dam and several reflections ofaseismic design for high rock-fill damrdquo in Proceedings of theEarth and Space pp 3177ndash3189 March 2010
Shock and Vibration 15
[8] A BayraktarM E Kartal and S Adanur ldquoThe effect of concreteslabrockfill interface behavior on the earthquake performanceof a CFR damrdquo International Journal of Non-Linear Mechanicsvol 46 no 1 pp 35ndash46 2011
[9] R P Piao A H Rippe B Myers and K W Lane ldquoEarthdam liquefaction and deformation analysis using numericalmodelingrdquo in Proceedings of the GeoCongress pp 1ndash6 March2006
[10] A W Elgamal ldquoThree-dimensional seismic analysis of la villitadamrdquo Journal of Geotechnical Engineering vol 118 no 12 pp1937ndash1958 1992
[11] B Gordan and B A Azlan ldquoEffect of material properties inCFRD tailing-embankment bridge during a strong earthquakerdquoCaspian Journal of Applied Sciences Research vol 2 no 11 pp61ndash72 2013
[12] A Papalou and J Bielak ldquoSeismic elastic response of Earthdams with canyon interactionrdquo Journal of Geotechnical andGeoenvironmental Engineering vol 127 no 5 pp 446ndash453 2001
[13] Y Yu L Xie and B Zhang ldquoStability of earth-rockfill damsinfluence of geometry on the three-dimensional effectrdquo Com-puters and Geotechnics vol 32 no 5 pp 326ndash339 2005
[14] L H Mejia and H B Seed ldquoComparison of 2-D and 3-D dynamic analyses of earth damsrdquo Journal of GeotechnicalEngineering vol 109 no 11 pp 1383ndash1398 1983
[15] J L Borges ldquoThree-dimensional analysis of embankmentson soft soils incorporating vertical drains by finite elementmethodrdquoComputers andGeotechnics vol 31 no 8 pp 665ndash6762004
[16] A Yildiz ldquoNumerical analyses of embankments on PVDimproved soft claysrdquo Advances in Engineering Software vol 40no 10 pp 1047ndash1055 2009
[17] B Le Hello and P Villard ldquoEmbankments reinforced by pilesand geosynthetics-Numerical and experimental studies dealingwith the transfer of load on the soil embankmentrdquo EngineeringGeology vol 106 no 1-2 pp 78ndash91 2009
[18] S W Abusharar J J Zheng B G Chen and J H Yin ldquoA sim-plified method for analysis of a piled embankment reinforcedwith geosyntheticsrdquo Geotextiles and Geomembranes vol 27 no1 pp 39ndash52 2009
[19] R Noorzad and M Omidvar ldquoSeismic displacement analysisof embankment dams with reinforced cohesive shellrdquo SoilDynamics and Earthquake Engineering vol 30 no 11 pp 1149ndash1157 2010
[20] T Matsumaru K Watanabe and J Isono ldquoApplication ofcement-mixed gravel reinforced by ground for soft groundimprovementrdquo in Proceedings of the 4th Asian Regional Confer-ence on Geosynthetics pp 380ndash385 Shanghai China June 2008
[21] Namdar and A A K Pelko ldquoSeismic evaluation of embank-ment shaking table test and finite element methodrdquo ThePacific Journal of Science and Technology vol 11 no 2 2010httpwwwakamaiuniversityusPJST
[22] L Wang G Zhang and J Zhang ldquoCentrifuge model tests ofgeotextile-reinforced soil embankments during an earthquakerdquoGeotextiles and Geomembranes vol 29 no 3 pp 222ndash232 2011
[23] H B Seed R T Wong I M Idriss and K Tokimatsu ldquoModuliand damping factors for dynamic analyses of cohesionless soilsrdquoJournal of Geotechnical Engineering vol 112 no 11 pp 1016ndash1032 1986
[24] B M Das Advanced Soil Mechanics CRC Press New York NYUSA 2013
[25] M J Griffin Handbook of Human Vibration Academic PressNew York NY USA 2012
[26] J Garnier C Gaudin S M Springman P J Culligan DJ Goodings and D Konig ldquoCatalogue of scaling laws andsimilitude questions in geotechnical centrifuge modellingrdquoInternational Journal of Physical Modelling in Geotechnics vol7 no 3 pp 1ndash23 2007
[27] A Fluent 120 Userrsquos Guide User Inputs for PorousMedia 2009
International Journal of
AerospaceEngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
RoboticsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Active and Passive Electronic Components
Control Scienceand Engineering
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
International Journal of
RotatingMachinery
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporation httpwwwhindawicom
Journal ofEngineeringVolume 2014
Submit your manuscripts athttpwwwhindawicom
VLSI Design
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Shock and Vibration
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Civil EngineeringAdvances in
Acoustics and VibrationAdvances in
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Electrical and Computer Engineering
Journal of
Advances inOptoElectronics
Hindawi Publishing Corporation httpwwwhindawicom
Volume 2014
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
SensorsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Modelling amp Simulation in EngineeringHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Chemical EngineeringInternational Journal of Antennas and
Propagation
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Navigation and Observation
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
DistributedSensor Networks
International Journal of
Shock and Vibration 11
0 20 40 60 80 100 1200
minus01
minus02
minus03
minus04
minus05
minus06
62 minus029
90 minus048
Time (s)
Disp
lace
men
t (m
m)
Time (s)0 10 20 30 40 50 60 70 80 90 100 110 120
03
025
02
015
01
005
0
Rela
tive
disp
lace
men
t (m
m)
96 024
Model A
0 20 40 60 80 100 120
Time (s)
Disp
lace
men
t (m
m) 2
15
1
05
0
minus05
minus1
minus15
84 15
104 minus064
Time (s)0 10 20 30 40 50 60 70 80 90 100 110 120
Rela
tive
disp
lace
men
t (m
m) 25
2
15
1
05
0
minus05
minus1
104 213
Model B
0 20 40 60 80 100 120
Time (s)
Disp
lace
men
t (m
m)
01201008006004002
0minus002minus004
108 01
108 006
Time (s)
0 10 20 30 40 50 60 70 80 90 100 110 120
Rela
tive
disp
lace
men
t (m
m)
007
006
005
004
003
002
001
0
8 006
Model C
Time (s)0 10 20 30 40 50 60 70 80 90 100 110 120
Rela
tive
disp
lace
men
t (m
m)
0201501005
0minus005minus01minus015minus02
90 017
26 minus017
0 20 40 60 80 100 120
Time (s)
Disp
lace
men
t (m
m) 015
01005
0
minus01minus015
minus005
minus02minus025
114 minus007116 minus022
Model DTime (s)
Disp
lace
men
t (m
m)
01
0
minus01
minus02
minus03
minus04
104 minus011
102 minus033
0 20 40 60 80 100 120
Up streamDown stream
Time (s)
0 10 20 30 40 50 60 70 80 90 100 110 120
Rela
tive
disp
lace
men
t (m
m)
03
025
02
015
01
0
005
86 025
Model E
Figure 19 Vertical displacement in both edges of the crest in models with relative displacement
12 Shock and Vibration
(a) (b) (c)
Figure 20 Damage in the first model (Model A)
(a) (b)
(c) (d)
Figure 21 Damage in the second model (Model B)
42 Free Vibration Analysis and Dominant Frequency Interms of modal analysis the free vibration analysis was cal-culated by ANSYS program Figure 16 shows displacement inthree directions of model and total displacement in the firstvibration mode because based on distribution of frequencyin the first mode to fifth mode it is important to note thatthe minimum frequency (022986Hz) was observed in thefirst vibration mode It means that the vibration period wasmaximum and critical in this mode
Distribution of frequency in different vibration modesindicated that this value was respectively obtained at026257Hz 028387Hz and 030135Hz in the vibration shapemodes 2 to 4
5 Results and Discussion Based on PhysicalSmall Scale Modeling
In order to find the best location of reinforcement in damfive small dams with different locations of reinforcementusing IDL material were vibrated by dominant frequency
(22986Hz) with respect to resonance condition Figure 17shows five small scale dams (Models (a) (b) (c) and (d))it is obvious that models have the same dimension In thisfigure the reinforced area was illustrated with a hatch areaFor example Model (d) indicated that all dam body wasreinforced For this purpose one steel box for modeling wasused This box made by five sheets of Plexiglas with 20mmthickness One of them was in the base of model The levelof reservoir was 75 of the dam height The scale parameterwas 1100 Itmeans thatmodel was one hundred times smallerthan prototypeThedamheightwas 227meter in reality but itwas made 227 cm in physical model In addition small scalemodeling was coupled by foundation Foundation materialwas dense sand with 75 relative density Sand propertieswere mentioned in soil mechanic test Figure 18 shows somedetails including dam perspective soil compaction networkindex and reservoir In this Figure two LVDT on the middleof model at the both edges of the crest were installed Inorder to achieve support one steel frame and one steel beamwere applied (see Figure 18(a)) However both LVDT wereconnected to data logger device by specific cables In terms
Shock and Vibration 13
(a) (b)
Figure 22 Damage in the third model (Model C)
of compaction soil for each layer the steel roller used wasselected by trial error methodWoodmolding with respect tocontrol slope via network index was used In order to avoidabsorption of soil water content both the described moldswere just soaked by water before use For tank purpose smallscale models were filled up by water with very slow rate
After vibration equal to two minutes for all modelsthe vertical displacement for both slopes such as upstreamand downstream were printed With respect to use of Excelprogram Figure 19 shows the distribution of vertical displace-ment in both edges in the middle of the crest and relativedisplacement in all models It was obvious that distributionof the vertical displacement indicated a same trend for bothmodels such as A and E In both models displacement valueswere negative during the vibration It means that both ofthem were in uplift condition In this figure also maximumandminimum peak of the relative displacement respectivelyoccurred in Models B and C with 213mm and 006mm It isalso worth noting that this value was at convergence positionfor Models A and E with 024mm and 025mm respectively
In terms of damage location in models Figure 20 showsthe damage in Model A which occurred at upstream anddownstream The level of damage was greater in upstream Itwas very sensible occurrence in case of hydrodynamic pres-sure along the vibration Also in this figure the maximumlongitudes cracks (see line C) were observed near to themiddle of dam at the crest For damage at downstream thetransverse cracks significantly occurred in dam toe
Figure 21 shows Model B that was damaged after vibra-tion It can be observed that dam was significantly damagedin some locations such as crest and surfaces Body cracks andfailure process dramatically occurred in both areas near toabutments Also in this figure one transverse crack in themiddle of the crest was seen (see Figure 20(c)) This damagewas significantly repeated at upstream in Model C but itwas placed in dam toe and it can be seen in Figure 22 Inaddition Model D was damaged in three places such as bothabutments and the middle of the upstream Figure 23 showsModel D that was damaged in toe Briefly all four modelswere damaged as discussed previously On the other handa successful way in order to remove damage was obtained inModel E as shown in Figure 24 Figure 24 shows that model
Figure 23 Damage in the fourth model (Model D)
was safe after vibration without any damage In this figurethe reinforced blanket layer using IDLmaterial was indicatedby red circles between dam and foundation In addition itwas very important to note that both surfaces were safe anddam was stable under severe seismic loading like resonancemotion In fact a good absorption of energy with respectto increase of damping was found by using IDL In case ofusing this technique displacement in both edges of the crestwith negative value indicated the uplift situation Moreoverrelative displacement was like the first model Thereforedam behavior before and after reinforcement was similar forboth distributions of displacement Nevertheless Model Ewas successful to remove damage with respect to high levelof damping in blanket layer In fact this model shows theexcellent performance in earth dams when the blanket layerwas expanded below tank
Finally blanket layer using isolator damper layer (IDL)below dam and tank is a good recommendation for earthdams in seismic zonewhen reinforced thickness is one-fourthof damheight As recommended optimization of thickness inthis method is the next study
6 Conclusion
In this study the earth dam performance under severeseismic motion such as resonance was evaluated by usingblanket layer (IDL) With respect to soil mechanic testthe optimum mixture for IDL was designed IDL powderwas made by using some materials Main material was alocal soil (laterite) with 90 and additives such as TDA
14 Shock and Vibration
(a) (b)
(c) (d)
Figure 24 Dam stabilization in the fifth model (Model E)
(tire derived aggregate with 7) and MS (microsilica) with3 were used This material was utilized to reinforce damin small scale physical modeling According to numericalanalysis the dominant frequency (02298Hz) in order tohave maximum effect for modeling vibration was computedBy using this frequency for physical modeling the damagelocation and distribution of vertical displacement at bothedges of the crest in the middle of small dams for five smallmodel with scale 1100 were discussed As results the bestperformance in order to remove damages was obviouslyobserved in Model E while other models were dramaticallydamaged in some locations such as upstream downstreamand crest In addition the thickness of blanket layer in thismodel was one-fourth of dam height Finally this model is anovel method to reinforce dam under strong earthquake likeresonance phenomena recommended for earth dam designin seismic zone
Conflict of Interests
The authors declare that there is no conflict of interestsregarding the publication of this paper
Acknowledgment
This study ismade possible by the support of the InternationalDoctorate Fellowship of Universiti Teknologi Malaysia andit is very much appreciated
References
[1] M Zeghal and A M Abdel-Ghaffar ldquoAnalysis of behavior ofearth dam using strong-motion earthquakes recordsrdquo Journalof Geotechnical Engineering vol 118 no 2 pp 266ndash277 1992
[2] V Gikas andM Sakellariou ldquoSettlement analysis of theMornosearth dam (Greece) evidence from numerical modeling andgeodetic monitoringrdquo Engineering Structures vol 30 no 11 pp3074ndash3081 2008
[3] R Verdugo N Sitar J D Frost et al ldquoSeismic performanceof earth structures during the February 2010 Maule Chileearthquake dams levees tailings dams and retaining wallsrdquoEarthquake Spectra vol 28 no 1 pp S75ndashS96 2012
[4] Y Parish and F N Abadi ldquoDynamic behaviour of earth damsfor variation of earth material stiffnessrdquo Proceedings of WorldAcademy of Science Engineering and Technology vol 50 pp606ndash611 2009
[5] T G Berhe X T Wang and W Wu ldquoNumerical investigationinto the arrangement of clay core on the seismic performanceof earth damsrdquo in Proceedings of the GeoShanghai InternationalConference on Soil Dynamics and Earthquake Engineering pp131ndash138 ASCE June 2010
[6] Z F Xia G L Ye J HWang B Ye and F Zhang ldquoFully couplednumerical analysis of repeated shake-consolidation process ofearth embankment on liquefiable foundationrdquo Soil Dynamicsand Earthquake Engineering vol 30 no 11 pp 1309ndash1318 2010
[7] X J Kong Y Zhou B Xu and D G Zou ldquoAnalysis on seismicfailure mechanism of Zipingpu dam and several reflections ofaseismic design for high rock-fill damrdquo in Proceedings of theEarth and Space pp 3177ndash3189 March 2010
Shock and Vibration 15
[8] A BayraktarM E Kartal and S Adanur ldquoThe effect of concreteslabrockfill interface behavior on the earthquake performanceof a CFR damrdquo International Journal of Non-Linear Mechanicsvol 46 no 1 pp 35ndash46 2011
[9] R P Piao A H Rippe B Myers and K W Lane ldquoEarthdam liquefaction and deformation analysis using numericalmodelingrdquo in Proceedings of the GeoCongress pp 1ndash6 March2006
[10] A W Elgamal ldquoThree-dimensional seismic analysis of la villitadamrdquo Journal of Geotechnical Engineering vol 118 no 12 pp1937ndash1958 1992
[11] B Gordan and B A Azlan ldquoEffect of material properties inCFRD tailing-embankment bridge during a strong earthquakerdquoCaspian Journal of Applied Sciences Research vol 2 no 11 pp61ndash72 2013
[12] A Papalou and J Bielak ldquoSeismic elastic response of Earthdams with canyon interactionrdquo Journal of Geotechnical andGeoenvironmental Engineering vol 127 no 5 pp 446ndash453 2001
[13] Y Yu L Xie and B Zhang ldquoStability of earth-rockfill damsinfluence of geometry on the three-dimensional effectrdquo Com-puters and Geotechnics vol 32 no 5 pp 326ndash339 2005
[14] L H Mejia and H B Seed ldquoComparison of 2-D and 3-D dynamic analyses of earth damsrdquo Journal of GeotechnicalEngineering vol 109 no 11 pp 1383ndash1398 1983
[15] J L Borges ldquoThree-dimensional analysis of embankmentson soft soils incorporating vertical drains by finite elementmethodrdquoComputers andGeotechnics vol 31 no 8 pp 665ndash6762004
[16] A Yildiz ldquoNumerical analyses of embankments on PVDimproved soft claysrdquo Advances in Engineering Software vol 40no 10 pp 1047ndash1055 2009
[17] B Le Hello and P Villard ldquoEmbankments reinforced by pilesand geosynthetics-Numerical and experimental studies dealingwith the transfer of load on the soil embankmentrdquo EngineeringGeology vol 106 no 1-2 pp 78ndash91 2009
[18] S W Abusharar J J Zheng B G Chen and J H Yin ldquoA sim-plified method for analysis of a piled embankment reinforcedwith geosyntheticsrdquo Geotextiles and Geomembranes vol 27 no1 pp 39ndash52 2009
[19] R Noorzad and M Omidvar ldquoSeismic displacement analysisof embankment dams with reinforced cohesive shellrdquo SoilDynamics and Earthquake Engineering vol 30 no 11 pp 1149ndash1157 2010
[20] T Matsumaru K Watanabe and J Isono ldquoApplication ofcement-mixed gravel reinforced by ground for soft groundimprovementrdquo in Proceedings of the 4th Asian Regional Confer-ence on Geosynthetics pp 380ndash385 Shanghai China June 2008
[21] Namdar and A A K Pelko ldquoSeismic evaluation of embank-ment shaking table test and finite element methodrdquo ThePacific Journal of Science and Technology vol 11 no 2 2010httpwwwakamaiuniversityusPJST
[22] L Wang G Zhang and J Zhang ldquoCentrifuge model tests ofgeotextile-reinforced soil embankments during an earthquakerdquoGeotextiles and Geomembranes vol 29 no 3 pp 222ndash232 2011
[23] H B Seed R T Wong I M Idriss and K Tokimatsu ldquoModuliand damping factors for dynamic analyses of cohesionless soilsrdquoJournal of Geotechnical Engineering vol 112 no 11 pp 1016ndash1032 1986
[24] B M Das Advanced Soil Mechanics CRC Press New York NYUSA 2013
[25] M J Griffin Handbook of Human Vibration Academic PressNew York NY USA 2012
[26] J Garnier C Gaudin S M Springman P J Culligan DJ Goodings and D Konig ldquoCatalogue of scaling laws andsimilitude questions in geotechnical centrifuge modellingrdquoInternational Journal of Physical Modelling in Geotechnics vol7 no 3 pp 1ndash23 2007
[27] A Fluent 120 Userrsquos Guide User Inputs for PorousMedia 2009
International Journal of
AerospaceEngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
RoboticsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Active and Passive Electronic Components
Control Scienceand Engineering
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
International Journal of
RotatingMachinery
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporation httpwwwhindawicom
Journal ofEngineeringVolume 2014
Submit your manuscripts athttpwwwhindawicom
VLSI Design
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Shock and Vibration
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Civil EngineeringAdvances in
Acoustics and VibrationAdvances in
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Electrical and Computer Engineering
Journal of
Advances inOptoElectronics
Hindawi Publishing Corporation httpwwwhindawicom
Volume 2014
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
SensorsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Modelling amp Simulation in EngineeringHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Chemical EngineeringInternational Journal of Antennas and
Propagation
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Navigation and Observation
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
DistributedSensor Networks
International Journal of
12 Shock and Vibration
(a) (b) (c)
Figure 20 Damage in the first model (Model A)
(a) (b)
(c) (d)
Figure 21 Damage in the second model (Model B)
42 Free Vibration Analysis and Dominant Frequency Interms of modal analysis the free vibration analysis was cal-culated by ANSYS program Figure 16 shows displacement inthree directions of model and total displacement in the firstvibration mode because based on distribution of frequencyin the first mode to fifth mode it is important to note thatthe minimum frequency (022986Hz) was observed in thefirst vibration mode It means that the vibration period wasmaximum and critical in this mode
Distribution of frequency in different vibration modesindicated that this value was respectively obtained at026257Hz 028387Hz and 030135Hz in the vibration shapemodes 2 to 4
5 Results and Discussion Based on PhysicalSmall Scale Modeling
In order to find the best location of reinforcement in damfive small dams with different locations of reinforcementusing IDL material were vibrated by dominant frequency
(22986Hz) with respect to resonance condition Figure 17shows five small scale dams (Models (a) (b) (c) and (d))it is obvious that models have the same dimension In thisfigure the reinforced area was illustrated with a hatch areaFor example Model (d) indicated that all dam body wasreinforced For this purpose one steel box for modeling wasused This box made by five sheets of Plexiglas with 20mmthickness One of them was in the base of model The levelof reservoir was 75 of the dam height The scale parameterwas 1100 Itmeans thatmodel was one hundred times smallerthan prototypeThedamheightwas 227meter in reality but itwas made 227 cm in physical model In addition small scalemodeling was coupled by foundation Foundation materialwas dense sand with 75 relative density Sand propertieswere mentioned in soil mechanic test Figure 18 shows somedetails including dam perspective soil compaction networkindex and reservoir In this Figure two LVDT on the middleof model at the both edges of the crest were installed Inorder to achieve support one steel frame and one steel beamwere applied (see Figure 18(a)) However both LVDT wereconnected to data logger device by specific cables In terms
Shock and Vibration 13
(a) (b)
Figure 22 Damage in the third model (Model C)
of compaction soil for each layer the steel roller used wasselected by trial error methodWoodmolding with respect tocontrol slope via network index was used In order to avoidabsorption of soil water content both the described moldswere just soaked by water before use For tank purpose smallscale models were filled up by water with very slow rate
After vibration equal to two minutes for all modelsthe vertical displacement for both slopes such as upstreamand downstream were printed With respect to use of Excelprogram Figure 19 shows the distribution of vertical displace-ment in both edges in the middle of the crest and relativedisplacement in all models It was obvious that distributionof the vertical displacement indicated a same trend for bothmodels such as A and E In both models displacement valueswere negative during the vibration It means that both ofthem were in uplift condition In this figure also maximumandminimum peak of the relative displacement respectivelyoccurred in Models B and C with 213mm and 006mm It isalso worth noting that this value was at convergence positionfor Models A and E with 024mm and 025mm respectively
In terms of damage location in models Figure 20 showsthe damage in Model A which occurred at upstream anddownstream The level of damage was greater in upstream Itwas very sensible occurrence in case of hydrodynamic pres-sure along the vibration Also in this figure the maximumlongitudes cracks (see line C) were observed near to themiddle of dam at the crest For damage at downstream thetransverse cracks significantly occurred in dam toe
Figure 21 shows Model B that was damaged after vibra-tion It can be observed that dam was significantly damagedin some locations such as crest and surfaces Body cracks andfailure process dramatically occurred in both areas near toabutments Also in this figure one transverse crack in themiddle of the crest was seen (see Figure 20(c)) This damagewas significantly repeated at upstream in Model C but itwas placed in dam toe and it can be seen in Figure 22 Inaddition Model D was damaged in three places such as bothabutments and the middle of the upstream Figure 23 showsModel D that was damaged in toe Briefly all four modelswere damaged as discussed previously On the other handa successful way in order to remove damage was obtained inModel E as shown in Figure 24 Figure 24 shows that model
Figure 23 Damage in the fourth model (Model D)
was safe after vibration without any damage In this figurethe reinforced blanket layer using IDLmaterial was indicatedby red circles between dam and foundation In addition itwas very important to note that both surfaces were safe anddam was stable under severe seismic loading like resonancemotion In fact a good absorption of energy with respectto increase of damping was found by using IDL In case ofusing this technique displacement in both edges of the crestwith negative value indicated the uplift situation Moreoverrelative displacement was like the first model Thereforedam behavior before and after reinforcement was similar forboth distributions of displacement Nevertheless Model Ewas successful to remove damage with respect to high levelof damping in blanket layer In fact this model shows theexcellent performance in earth dams when the blanket layerwas expanded below tank
Finally blanket layer using isolator damper layer (IDL)below dam and tank is a good recommendation for earthdams in seismic zonewhen reinforced thickness is one-fourthof damheight As recommended optimization of thickness inthis method is the next study
6 Conclusion
In this study the earth dam performance under severeseismic motion such as resonance was evaluated by usingblanket layer (IDL) With respect to soil mechanic testthe optimum mixture for IDL was designed IDL powderwas made by using some materials Main material was alocal soil (laterite) with 90 and additives such as TDA
14 Shock and Vibration
(a) (b)
(c) (d)
Figure 24 Dam stabilization in the fifth model (Model E)
(tire derived aggregate with 7) and MS (microsilica) with3 were used This material was utilized to reinforce damin small scale physical modeling According to numericalanalysis the dominant frequency (02298Hz) in order tohave maximum effect for modeling vibration was computedBy using this frequency for physical modeling the damagelocation and distribution of vertical displacement at bothedges of the crest in the middle of small dams for five smallmodel with scale 1100 were discussed As results the bestperformance in order to remove damages was obviouslyobserved in Model E while other models were dramaticallydamaged in some locations such as upstream downstreamand crest In addition the thickness of blanket layer in thismodel was one-fourth of dam height Finally this model is anovel method to reinforce dam under strong earthquake likeresonance phenomena recommended for earth dam designin seismic zone
Conflict of Interests
The authors declare that there is no conflict of interestsregarding the publication of this paper
Acknowledgment
This study ismade possible by the support of the InternationalDoctorate Fellowship of Universiti Teknologi Malaysia andit is very much appreciated
References
[1] M Zeghal and A M Abdel-Ghaffar ldquoAnalysis of behavior ofearth dam using strong-motion earthquakes recordsrdquo Journalof Geotechnical Engineering vol 118 no 2 pp 266ndash277 1992
[2] V Gikas andM Sakellariou ldquoSettlement analysis of theMornosearth dam (Greece) evidence from numerical modeling andgeodetic monitoringrdquo Engineering Structures vol 30 no 11 pp3074ndash3081 2008
[3] R Verdugo N Sitar J D Frost et al ldquoSeismic performanceof earth structures during the February 2010 Maule Chileearthquake dams levees tailings dams and retaining wallsrdquoEarthquake Spectra vol 28 no 1 pp S75ndashS96 2012
[4] Y Parish and F N Abadi ldquoDynamic behaviour of earth damsfor variation of earth material stiffnessrdquo Proceedings of WorldAcademy of Science Engineering and Technology vol 50 pp606ndash611 2009
[5] T G Berhe X T Wang and W Wu ldquoNumerical investigationinto the arrangement of clay core on the seismic performanceof earth damsrdquo in Proceedings of the GeoShanghai InternationalConference on Soil Dynamics and Earthquake Engineering pp131ndash138 ASCE June 2010
[6] Z F Xia G L Ye J HWang B Ye and F Zhang ldquoFully couplednumerical analysis of repeated shake-consolidation process ofearth embankment on liquefiable foundationrdquo Soil Dynamicsand Earthquake Engineering vol 30 no 11 pp 1309ndash1318 2010
[7] X J Kong Y Zhou B Xu and D G Zou ldquoAnalysis on seismicfailure mechanism of Zipingpu dam and several reflections ofaseismic design for high rock-fill damrdquo in Proceedings of theEarth and Space pp 3177ndash3189 March 2010
Shock and Vibration 15
[8] A BayraktarM E Kartal and S Adanur ldquoThe effect of concreteslabrockfill interface behavior on the earthquake performanceof a CFR damrdquo International Journal of Non-Linear Mechanicsvol 46 no 1 pp 35ndash46 2011
[9] R P Piao A H Rippe B Myers and K W Lane ldquoEarthdam liquefaction and deformation analysis using numericalmodelingrdquo in Proceedings of the GeoCongress pp 1ndash6 March2006
[10] A W Elgamal ldquoThree-dimensional seismic analysis of la villitadamrdquo Journal of Geotechnical Engineering vol 118 no 12 pp1937ndash1958 1992
[11] B Gordan and B A Azlan ldquoEffect of material properties inCFRD tailing-embankment bridge during a strong earthquakerdquoCaspian Journal of Applied Sciences Research vol 2 no 11 pp61ndash72 2013
[12] A Papalou and J Bielak ldquoSeismic elastic response of Earthdams with canyon interactionrdquo Journal of Geotechnical andGeoenvironmental Engineering vol 127 no 5 pp 446ndash453 2001
[13] Y Yu L Xie and B Zhang ldquoStability of earth-rockfill damsinfluence of geometry on the three-dimensional effectrdquo Com-puters and Geotechnics vol 32 no 5 pp 326ndash339 2005
[14] L H Mejia and H B Seed ldquoComparison of 2-D and 3-D dynamic analyses of earth damsrdquo Journal of GeotechnicalEngineering vol 109 no 11 pp 1383ndash1398 1983
[15] J L Borges ldquoThree-dimensional analysis of embankmentson soft soils incorporating vertical drains by finite elementmethodrdquoComputers andGeotechnics vol 31 no 8 pp 665ndash6762004
[16] A Yildiz ldquoNumerical analyses of embankments on PVDimproved soft claysrdquo Advances in Engineering Software vol 40no 10 pp 1047ndash1055 2009
[17] B Le Hello and P Villard ldquoEmbankments reinforced by pilesand geosynthetics-Numerical and experimental studies dealingwith the transfer of load on the soil embankmentrdquo EngineeringGeology vol 106 no 1-2 pp 78ndash91 2009
[18] S W Abusharar J J Zheng B G Chen and J H Yin ldquoA sim-plified method for analysis of a piled embankment reinforcedwith geosyntheticsrdquo Geotextiles and Geomembranes vol 27 no1 pp 39ndash52 2009
[19] R Noorzad and M Omidvar ldquoSeismic displacement analysisof embankment dams with reinforced cohesive shellrdquo SoilDynamics and Earthquake Engineering vol 30 no 11 pp 1149ndash1157 2010
[20] T Matsumaru K Watanabe and J Isono ldquoApplication ofcement-mixed gravel reinforced by ground for soft groundimprovementrdquo in Proceedings of the 4th Asian Regional Confer-ence on Geosynthetics pp 380ndash385 Shanghai China June 2008
[21] Namdar and A A K Pelko ldquoSeismic evaluation of embank-ment shaking table test and finite element methodrdquo ThePacific Journal of Science and Technology vol 11 no 2 2010httpwwwakamaiuniversityusPJST
[22] L Wang G Zhang and J Zhang ldquoCentrifuge model tests ofgeotextile-reinforced soil embankments during an earthquakerdquoGeotextiles and Geomembranes vol 29 no 3 pp 222ndash232 2011
[23] H B Seed R T Wong I M Idriss and K Tokimatsu ldquoModuliand damping factors for dynamic analyses of cohesionless soilsrdquoJournal of Geotechnical Engineering vol 112 no 11 pp 1016ndash1032 1986
[24] B M Das Advanced Soil Mechanics CRC Press New York NYUSA 2013
[25] M J Griffin Handbook of Human Vibration Academic PressNew York NY USA 2012
[26] J Garnier C Gaudin S M Springman P J Culligan DJ Goodings and D Konig ldquoCatalogue of scaling laws andsimilitude questions in geotechnical centrifuge modellingrdquoInternational Journal of Physical Modelling in Geotechnics vol7 no 3 pp 1ndash23 2007
[27] A Fluent 120 Userrsquos Guide User Inputs for PorousMedia 2009
International Journal of
AerospaceEngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
RoboticsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Active and Passive Electronic Components
Control Scienceand Engineering
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
International Journal of
RotatingMachinery
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporation httpwwwhindawicom
Journal ofEngineeringVolume 2014
Submit your manuscripts athttpwwwhindawicom
VLSI Design
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Shock and Vibration
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Civil EngineeringAdvances in
Acoustics and VibrationAdvances in
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Electrical and Computer Engineering
Journal of
Advances inOptoElectronics
Hindawi Publishing Corporation httpwwwhindawicom
Volume 2014
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
SensorsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Modelling amp Simulation in EngineeringHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Chemical EngineeringInternational Journal of Antennas and
Propagation
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Navigation and Observation
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
DistributedSensor Networks
International Journal of
Shock and Vibration 13
(a) (b)
Figure 22 Damage in the third model (Model C)
of compaction soil for each layer the steel roller used wasselected by trial error methodWoodmolding with respect tocontrol slope via network index was used In order to avoidabsorption of soil water content both the described moldswere just soaked by water before use For tank purpose smallscale models were filled up by water with very slow rate
After vibration equal to two minutes for all modelsthe vertical displacement for both slopes such as upstreamand downstream were printed With respect to use of Excelprogram Figure 19 shows the distribution of vertical displace-ment in both edges in the middle of the crest and relativedisplacement in all models It was obvious that distributionof the vertical displacement indicated a same trend for bothmodels such as A and E In both models displacement valueswere negative during the vibration It means that both ofthem were in uplift condition In this figure also maximumandminimum peak of the relative displacement respectivelyoccurred in Models B and C with 213mm and 006mm It isalso worth noting that this value was at convergence positionfor Models A and E with 024mm and 025mm respectively
In terms of damage location in models Figure 20 showsthe damage in Model A which occurred at upstream anddownstream The level of damage was greater in upstream Itwas very sensible occurrence in case of hydrodynamic pres-sure along the vibration Also in this figure the maximumlongitudes cracks (see line C) were observed near to themiddle of dam at the crest For damage at downstream thetransverse cracks significantly occurred in dam toe
Figure 21 shows Model B that was damaged after vibra-tion It can be observed that dam was significantly damagedin some locations such as crest and surfaces Body cracks andfailure process dramatically occurred in both areas near toabutments Also in this figure one transverse crack in themiddle of the crest was seen (see Figure 20(c)) This damagewas significantly repeated at upstream in Model C but itwas placed in dam toe and it can be seen in Figure 22 Inaddition Model D was damaged in three places such as bothabutments and the middle of the upstream Figure 23 showsModel D that was damaged in toe Briefly all four modelswere damaged as discussed previously On the other handa successful way in order to remove damage was obtained inModel E as shown in Figure 24 Figure 24 shows that model
Figure 23 Damage in the fourth model (Model D)
was safe after vibration without any damage In this figurethe reinforced blanket layer using IDLmaterial was indicatedby red circles between dam and foundation In addition itwas very important to note that both surfaces were safe anddam was stable under severe seismic loading like resonancemotion In fact a good absorption of energy with respectto increase of damping was found by using IDL In case ofusing this technique displacement in both edges of the crestwith negative value indicated the uplift situation Moreoverrelative displacement was like the first model Thereforedam behavior before and after reinforcement was similar forboth distributions of displacement Nevertheless Model Ewas successful to remove damage with respect to high levelof damping in blanket layer In fact this model shows theexcellent performance in earth dams when the blanket layerwas expanded below tank
Finally blanket layer using isolator damper layer (IDL)below dam and tank is a good recommendation for earthdams in seismic zonewhen reinforced thickness is one-fourthof damheight As recommended optimization of thickness inthis method is the next study
6 Conclusion
In this study the earth dam performance under severeseismic motion such as resonance was evaluated by usingblanket layer (IDL) With respect to soil mechanic testthe optimum mixture for IDL was designed IDL powderwas made by using some materials Main material was alocal soil (laterite) with 90 and additives such as TDA
14 Shock and Vibration
(a) (b)
(c) (d)
Figure 24 Dam stabilization in the fifth model (Model E)
(tire derived aggregate with 7) and MS (microsilica) with3 were used This material was utilized to reinforce damin small scale physical modeling According to numericalanalysis the dominant frequency (02298Hz) in order tohave maximum effect for modeling vibration was computedBy using this frequency for physical modeling the damagelocation and distribution of vertical displacement at bothedges of the crest in the middle of small dams for five smallmodel with scale 1100 were discussed As results the bestperformance in order to remove damages was obviouslyobserved in Model E while other models were dramaticallydamaged in some locations such as upstream downstreamand crest In addition the thickness of blanket layer in thismodel was one-fourth of dam height Finally this model is anovel method to reinforce dam under strong earthquake likeresonance phenomena recommended for earth dam designin seismic zone
Conflict of Interests
The authors declare that there is no conflict of interestsregarding the publication of this paper
Acknowledgment
This study ismade possible by the support of the InternationalDoctorate Fellowship of Universiti Teknologi Malaysia andit is very much appreciated
References
[1] M Zeghal and A M Abdel-Ghaffar ldquoAnalysis of behavior ofearth dam using strong-motion earthquakes recordsrdquo Journalof Geotechnical Engineering vol 118 no 2 pp 266ndash277 1992
[2] V Gikas andM Sakellariou ldquoSettlement analysis of theMornosearth dam (Greece) evidence from numerical modeling andgeodetic monitoringrdquo Engineering Structures vol 30 no 11 pp3074ndash3081 2008
[3] R Verdugo N Sitar J D Frost et al ldquoSeismic performanceof earth structures during the February 2010 Maule Chileearthquake dams levees tailings dams and retaining wallsrdquoEarthquake Spectra vol 28 no 1 pp S75ndashS96 2012
[4] Y Parish and F N Abadi ldquoDynamic behaviour of earth damsfor variation of earth material stiffnessrdquo Proceedings of WorldAcademy of Science Engineering and Technology vol 50 pp606ndash611 2009
[5] T G Berhe X T Wang and W Wu ldquoNumerical investigationinto the arrangement of clay core on the seismic performanceof earth damsrdquo in Proceedings of the GeoShanghai InternationalConference on Soil Dynamics and Earthquake Engineering pp131ndash138 ASCE June 2010
[6] Z F Xia G L Ye J HWang B Ye and F Zhang ldquoFully couplednumerical analysis of repeated shake-consolidation process ofearth embankment on liquefiable foundationrdquo Soil Dynamicsand Earthquake Engineering vol 30 no 11 pp 1309ndash1318 2010
[7] X J Kong Y Zhou B Xu and D G Zou ldquoAnalysis on seismicfailure mechanism of Zipingpu dam and several reflections ofaseismic design for high rock-fill damrdquo in Proceedings of theEarth and Space pp 3177ndash3189 March 2010
Shock and Vibration 15
[8] A BayraktarM E Kartal and S Adanur ldquoThe effect of concreteslabrockfill interface behavior on the earthquake performanceof a CFR damrdquo International Journal of Non-Linear Mechanicsvol 46 no 1 pp 35ndash46 2011
[9] R P Piao A H Rippe B Myers and K W Lane ldquoEarthdam liquefaction and deformation analysis using numericalmodelingrdquo in Proceedings of the GeoCongress pp 1ndash6 March2006
[10] A W Elgamal ldquoThree-dimensional seismic analysis of la villitadamrdquo Journal of Geotechnical Engineering vol 118 no 12 pp1937ndash1958 1992
[11] B Gordan and B A Azlan ldquoEffect of material properties inCFRD tailing-embankment bridge during a strong earthquakerdquoCaspian Journal of Applied Sciences Research vol 2 no 11 pp61ndash72 2013
[12] A Papalou and J Bielak ldquoSeismic elastic response of Earthdams with canyon interactionrdquo Journal of Geotechnical andGeoenvironmental Engineering vol 127 no 5 pp 446ndash453 2001
[13] Y Yu L Xie and B Zhang ldquoStability of earth-rockfill damsinfluence of geometry on the three-dimensional effectrdquo Com-puters and Geotechnics vol 32 no 5 pp 326ndash339 2005
[14] L H Mejia and H B Seed ldquoComparison of 2-D and 3-D dynamic analyses of earth damsrdquo Journal of GeotechnicalEngineering vol 109 no 11 pp 1383ndash1398 1983
[15] J L Borges ldquoThree-dimensional analysis of embankmentson soft soils incorporating vertical drains by finite elementmethodrdquoComputers andGeotechnics vol 31 no 8 pp 665ndash6762004
[16] A Yildiz ldquoNumerical analyses of embankments on PVDimproved soft claysrdquo Advances in Engineering Software vol 40no 10 pp 1047ndash1055 2009
[17] B Le Hello and P Villard ldquoEmbankments reinforced by pilesand geosynthetics-Numerical and experimental studies dealingwith the transfer of load on the soil embankmentrdquo EngineeringGeology vol 106 no 1-2 pp 78ndash91 2009
[18] S W Abusharar J J Zheng B G Chen and J H Yin ldquoA sim-plified method for analysis of a piled embankment reinforcedwith geosyntheticsrdquo Geotextiles and Geomembranes vol 27 no1 pp 39ndash52 2009
[19] R Noorzad and M Omidvar ldquoSeismic displacement analysisof embankment dams with reinforced cohesive shellrdquo SoilDynamics and Earthquake Engineering vol 30 no 11 pp 1149ndash1157 2010
[20] T Matsumaru K Watanabe and J Isono ldquoApplication ofcement-mixed gravel reinforced by ground for soft groundimprovementrdquo in Proceedings of the 4th Asian Regional Confer-ence on Geosynthetics pp 380ndash385 Shanghai China June 2008
[21] Namdar and A A K Pelko ldquoSeismic evaluation of embank-ment shaking table test and finite element methodrdquo ThePacific Journal of Science and Technology vol 11 no 2 2010httpwwwakamaiuniversityusPJST
[22] L Wang G Zhang and J Zhang ldquoCentrifuge model tests ofgeotextile-reinforced soil embankments during an earthquakerdquoGeotextiles and Geomembranes vol 29 no 3 pp 222ndash232 2011
[23] H B Seed R T Wong I M Idriss and K Tokimatsu ldquoModuliand damping factors for dynamic analyses of cohesionless soilsrdquoJournal of Geotechnical Engineering vol 112 no 11 pp 1016ndash1032 1986
[24] B M Das Advanced Soil Mechanics CRC Press New York NYUSA 2013
[25] M J Griffin Handbook of Human Vibration Academic PressNew York NY USA 2012
[26] J Garnier C Gaudin S M Springman P J Culligan DJ Goodings and D Konig ldquoCatalogue of scaling laws andsimilitude questions in geotechnical centrifuge modellingrdquoInternational Journal of Physical Modelling in Geotechnics vol7 no 3 pp 1ndash23 2007
[27] A Fluent 120 Userrsquos Guide User Inputs for PorousMedia 2009
International Journal of
AerospaceEngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
RoboticsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Active and Passive Electronic Components
Control Scienceand Engineering
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
International Journal of
RotatingMachinery
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporation httpwwwhindawicom
Journal ofEngineeringVolume 2014
Submit your manuscripts athttpwwwhindawicom
VLSI Design
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Shock and Vibration
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Civil EngineeringAdvances in
Acoustics and VibrationAdvances in
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Electrical and Computer Engineering
Journal of
Advances inOptoElectronics
Hindawi Publishing Corporation httpwwwhindawicom
Volume 2014
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
SensorsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Modelling amp Simulation in EngineeringHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Chemical EngineeringInternational Journal of Antennas and
Propagation
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Navigation and Observation
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
DistributedSensor Networks
International Journal of
14 Shock and Vibration
(a) (b)
(c) (d)
Figure 24 Dam stabilization in the fifth model (Model E)
(tire derived aggregate with 7) and MS (microsilica) with3 were used This material was utilized to reinforce damin small scale physical modeling According to numericalanalysis the dominant frequency (02298Hz) in order tohave maximum effect for modeling vibration was computedBy using this frequency for physical modeling the damagelocation and distribution of vertical displacement at bothedges of the crest in the middle of small dams for five smallmodel with scale 1100 were discussed As results the bestperformance in order to remove damages was obviouslyobserved in Model E while other models were dramaticallydamaged in some locations such as upstream downstreamand crest In addition the thickness of blanket layer in thismodel was one-fourth of dam height Finally this model is anovel method to reinforce dam under strong earthquake likeresonance phenomena recommended for earth dam designin seismic zone
Conflict of Interests
The authors declare that there is no conflict of interestsregarding the publication of this paper
Acknowledgment
This study ismade possible by the support of the InternationalDoctorate Fellowship of Universiti Teknologi Malaysia andit is very much appreciated
References
[1] M Zeghal and A M Abdel-Ghaffar ldquoAnalysis of behavior ofearth dam using strong-motion earthquakes recordsrdquo Journalof Geotechnical Engineering vol 118 no 2 pp 266ndash277 1992
[2] V Gikas andM Sakellariou ldquoSettlement analysis of theMornosearth dam (Greece) evidence from numerical modeling andgeodetic monitoringrdquo Engineering Structures vol 30 no 11 pp3074ndash3081 2008
[3] R Verdugo N Sitar J D Frost et al ldquoSeismic performanceof earth structures during the February 2010 Maule Chileearthquake dams levees tailings dams and retaining wallsrdquoEarthquake Spectra vol 28 no 1 pp S75ndashS96 2012
[4] Y Parish and F N Abadi ldquoDynamic behaviour of earth damsfor variation of earth material stiffnessrdquo Proceedings of WorldAcademy of Science Engineering and Technology vol 50 pp606ndash611 2009
[5] T G Berhe X T Wang and W Wu ldquoNumerical investigationinto the arrangement of clay core on the seismic performanceof earth damsrdquo in Proceedings of the GeoShanghai InternationalConference on Soil Dynamics and Earthquake Engineering pp131ndash138 ASCE June 2010
[6] Z F Xia G L Ye J HWang B Ye and F Zhang ldquoFully couplednumerical analysis of repeated shake-consolidation process ofearth embankment on liquefiable foundationrdquo Soil Dynamicsand Earthquake Engineering vol 30 no 11 pp 1309ndash1318 2010
[7] X J Kong Y Zhou B Xu and D G Zou ldquoAnalysis on seismicfailure mechanism of Zipingpu dam and several reflections ofaseismic design for high rock-fill damrdquo in Proceedings of theEarth and Space pp 3177ndash3189 March 2010
Shock and Vibration 15
[8] A BayraktarM E Kartal and S Adanur ldquoThe effect of concreteslabrockfill interface behavior on the earthquake performanceof a CFR damrdquo International Journal of Non-Linear Mechanicsvol 46 no 1 pp 35ndash46 2011
[9] R P Piao A H Rippe B Myers and K W Lane ldquoEarthdam liquefaction and deformation analysis using numericalmodelingrdquo in Proceedings of the GeoCongress pp 1ndash6 March2006
[10] A W Elgamal ldquoThree-dimensional seismic analysis of la villitadamrdquo Journal of Geotechnical Engineering vol 118 no 12 pp1937ndash1958 1992
[11] B Gordan and B A Azlan ldquoEffect of material properties inCFRD tailing-embankment bridge during a strong earthquakerdquoCaspian Journal of Applied Sciences Research vol 2 no 11 pp61ndash72 2013
[12] A Papalou and J Bielak ldquoSeismic elastic response of Earthdams with canyon interactionrdquo Journal of Geotechnical andGeoenvironmental Engineering vol 127 no 5 pp 446ndash453 2001
[13] Y Yu L Xie and B Zhang ldquoStability of earth-rockfill damsinfluence of geometry on the three-dimensional effectrdquo Com-puters and Geotechnics vol 32 no 5 pp 326ndash339 2005
[14] L H Mejia and H B Seed ldquoComparison of 2-D and 3-D dynamic analyses of earth damsrdquo Journal of GeotechnicalEngineering vol 109 no 11 pp 1383ndash1398 1983
[15] J L Borges ldquoThree-dimensional analysis of embankmentson soft soils incorporating vertical drains by finite elementmethodrdquoComputers andGeotechnics vol 31 no 8 pp 665ndash6762004
[16] A Yildiz ldquoNumerical analyses of embankments on PVDimproved soft claysrdquo Advances in Engineering Software vol 40no 10 pp 1047ndash1055 2009
[17] B Le Hello and P Villard ldquoEmbankments reinforced by pilesand geosynthetics-Numerical and experimental studies dealingwith the transfer of load on the soil embankmentrdquo EngineeringGeology vol 106 no 1-2 pp 78ndash91 2009
[18] S W Abusharar J J Zheng B G Chen and J H Yin ldquoA sim-plified method for analysis of a piled embankment reinforcedwith geosyntheticsrdquo Geotextiles and Geomembranes vol 27 no1 pp 39ndash52 2009
[19] R Noorzad and M Omidvar ldquoSeismic displacement analysisof embankment dams with reinforced cohesive shellrdquo SoilDynamics and Earthquake Engineering vol 30 no 11 pp 1149ndash1157 2010
[20] T Matsumaru K Watanabe and J Isono ldquoApplication ofcement-mixed gravel reinforced by ground for soft groundimprovementrdquo in Proceedings of the 4th Asian Regional Confer-ence on Geosynthetics pp 380ndash385 Shanghai China June 2008
[21] Namdar and A A K Pelko ldquoSeismic evaluation of embank-ment shaking table test and finite element methodrdquo ThePacific Journal of Science and Technology vol 11 no 2 2010httpwwwakamaiuniversityusPJST
[22] L Wang G Zhang and J Zhang ldquoCentrifuge model tests ofgeotextile-reinforced soil embankments during an earthquakerdquoGeotextiles and Geomembranes vol 29 no 3 pp 222ndash232 2011
[23] H B Seed R T Wong I M Idriss and K Tokimatsu ldquoModuliand damping factors for dynamic analyses of cohesionless soilsrdquoJournal of Geotechnical Engineering vol 112 no 11 pp 1016ndash1032 1986
[24] B M Das Advanced Soil Mechanics CRC Press New York NYUSA 2013
[25] M J Griffin Handbook of Human Vibration Academic PressNew York NY USA 2012
[26] J Garnier C Gaudin S M Springman P J Culligan DJ Goodings and D Konig ldquoCatalogue of scaling laws andsimilitude questions in geotechnical centrifuge modellingrdquoInternational Journal of Physical Modelling in Geotechnics vol7 no 3 pp 1ndash23 2007
[27] A Fluent 120 Userrsquos Guide User Inputs for PorousMedia 2009
International Journal of
AerospaceEngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
RoboticsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Active and Passive Electronic Components
Control Scienceand Engineering
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
International Journal of
RotatingMachinery
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporation httpwwwhindawicom
Journal ofEngineeringVolume 2014
Submit your manuscripts athttpwwwhindawicom
VLSI Design
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Shock and Vibration
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Civil EngineeringAdvances in
Acoustics and VibrationAdvances in
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Electrical and Computer Engineering
Journal of
Advances inOptoElectronics
Hindawi Publishing Corporation httpwwwhindawicom
Volume 2014
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
SensorsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Modelling amp Simulation in EngineeringHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Chemical EngineeringInternational Journal of Antennas and
Propagation
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Navigation and Observation
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
DistributedSensor Networks
International Journal of
Shock and Vibration 15
[8] A BayraktarM E Kartal and S Adanur ldquoThe effect of concreteslabrockfill interface behavior on the earthquake performanceof a CFR damrdquo International Journal of Non-Linear Mechanicsvol 46 no 1 pp 35ndash46 2011
[9] R P Piao A H Rippe B Myers and K W Lane ldquoEarthdam liquefaction and deformation analysis using numericalmodelingrdquo in Proceedings of the GeoCongress pp 1ndash6 March2006
[10] A W Elgamal ldquoThree-dimensional seismic analysis of la villitadamrdquo Journal of Geotechnical Engineering vol 118 no 12 pp1937ndash1958 1992
[11] B Gordan and B A Azlan ldquoEffect of material properties inCFRD tailing-embankment bridge during a strong earthquakerdquoCaspian Journal of Applied Sciences Research vol 2 no 11 pp61ndash72 2013
[12] A Papalou and J Bielak ldquoSeismic elastic response of Earthdams with canyon interactionrdquo Journal of Geotechnical andGeoenvironmental Engineering vol 127 no 5 pp 446ndash453 2001
[13] Y Yu L Xie and B Zhang ldquoStability of earth-rockfill damsinfluence of geometry on the three-dimensional effectrdquo Com-puters and Geotechnics vol 32 no 5 pp 326ndash339 2005
[14] L H Mejia and H B Seed ldquoComparison of 2-D and 3-D dynamic analyses of earth damsrdquo Journal of GeotechnicalEngineering vol 109 no 11 pp 1383ndash1398 1983
[15] J L Borges ldquoThree-dimensional analysis of embankmentson soft soils incorporating vertical drains by finite elementmethodrdquoComputers andGeotechnics vol 31 no 8 pp 665ndash6762004
[16] A Yildiz ldquoNumerical analyses of embankments on PVDimproved soft claysrdquo Advances in Engineering Software vol 40no 10 pp 1047ndash1055 2009
[17] B Le Hello and P Villard ldquoEmbankments reinforced by pilesand geosynthetics-Numerical and experimental studies dealingwith the transfer of load on the soil embankmentrdquo EngineeringGeology vol 106 no 1-2 pp 78ndash91 2009
[18] S W Abusharar J J Zheng B G Chen and J H Yin ldquoA sim-plified method for analysis of a piled embankment reinforcedwith geosyntheticsrdquo Geotextiles and Geomembranes vol 27 no1 pp 39ndash52 2009
[19] R Noorzad and M Omidvar ldquoSeismic displacement analysisof embankment dams with reinforced cohesive shellrdquo SoilDynamics and Earthquake Engineering vol 30 no 11 pp 1149ndash1157 2010
[20] T Matsumaru K Watanabe and J Isono ldquoApplication ofcement-mixed gravel reinforced by ground for soft groundimprovementrdquo in Proceedings of the 4th Asian Regional Confer-ence on Geosynthetics pp 380ndash385 Shanghai China June 2008
[21] Namdar and A A K Pelko ldquoSeismic evaluation of embank-ment shaking table test and finite element methodrdquo ThePacific Journal of Science and Technology vol 11 no 2 2010httpwwwakamaiuniversityusPJST
[22] L Wang G Zhang and J Zhang ldquoCentrifuge model tests ofgeotextile-reinforced soil embankments during an earthquakerdquoGeotextiles and Geomembranes vol 29 no 3 pp 222ndash232 2011
[23] H B Seed R T Wong I M Idriss and K Tokimatsu ldquoModuliand damping factors for dynamic analyses of cohesionless soilsrdquoJournal of Geotechnical Engineering vol 112 no 11 pp 1016ndash1032 1986
[24] B M Das Advanced Soil Mechanics CRC Press New York NYUSA 2013
[25] M J Griffin Handbook of Human Vibration Academic PressNew York NY USA 2012
[26] J Garnier C Gaudin S M Springman P J Culligan DJ Goodings and D Konig ldquoCatalogue of scaling laws andsimilitude questions in geotechnical centrifuge modellingrdquoInternational Journal of Physical Modelling in Geotechnics vol7 no 3 pp 1ndash23 2007
[27] A Fluent 120 Userrsquos Guide User Inputs for PorousMedia 2009
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Volume 2014
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
SensorsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Modelling amp Simulation in EngineeringHindawi Publishing Corporation httpwwwhindawicom Volume 2014
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Chemical EngineeringInternational Journal of Antennas and
Propagation
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Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Navigation and Observation
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
DistributedSensor Networks
International Journal of
International Journal of
AerospaceEngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
RoboticsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Active and Passive Electronic Components
Control Scienceand Engineering
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
International Journal of
RotatingMachinery
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporation httpwwwhindawicom
Journal ofEngineeringVolume 2014
Submit your manuscripts athttpwwwhindawicom
VLSI Design
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Shock and Vibration
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Civil EngineeringAdvances in
Acoustics and VibrationAdvances in
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Electrical and Computer Engineering
Journal of
Advances inOptoElectronics
Hindawi Publishing Corporation httpwwwhindawicom
Volume 2014
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
SensorsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Modelling amp Simulation in EngineeringHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Chemical EngineeringInternational Journal of Antennas and
Propagation
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Navigation and Observation
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
DistributedSensor Networks
International Journal of
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