january 24, 2011 project no. 210-187 encana oil gas (usa ... · ) january 24, 2011 project no....

)

January 24, 2011 Project No. 210-187

Mr. Jeff Schaefer EnCana Oil & Gas (USA), Inc. 370 1 ih Street, Suite 1700 Denver, Colorado 80202

Subject: Additional Geotechnical Recommendations, Middle Fork Compressor Station in Garfield County, Colorado.

Dear Mr. Schaefer,

Yeh and Associates, Inc. prepared a Geotechnical Investigation for five proposed water tanks at the Middle Fork Compressor Station in Garfield County, Colorado (Project No. 210-187, report dated December 2, 2010). We recommended tanks be supported on a deep foundation system such as helical piers or micropiles. Yeh and Associates was requested to provide additional shallow foundation and other geotechnical related recommendations. We were informed that storage tanks will be 120 feet in diameter and 42 feet in height. Tank foundation loads will be on the order of 3,000 psf. Based on loads provided, we anticipate foundation loads for the VDU vessels and containment walls will be on the order of 1,500 psf.

SHALLOW FOUNDATION RECOMMENDATIONS Our investigation encountered existing, uncontrolled fill and natural, soft soils. We

estimate settlement due to tank loading to be on the order of 9 to 18 inches. For the VDU vessel and containment walls, we estimate settlements on the order of 1 to 3 inches for foundations placed on the existing fill soils. If estimated settlements cannot be tolerated during the service life of the structure, we recommend subexcavation be performed below these foundations. As an alternative, rammed aggregate piers (Geopiers) could be used to improve shallow soils to allow for the use of shallow foundations. Recommendations for pad, mat, ringwall and spread footing foundations are as follows:

Storage Tanks 1. We recommend removal and replacement of the existing soils as a moisture

conditioned fill (subexcavation) to a depth of 9 feet below proposed tank bottoms and/or ringwall foundations, whichever is deeper. The sides of the subexcavation should be sloped at 1 H:1V from the base of the excavation. In addition, we recommend the placement of a biaxial geogrid be placed within 2 feet of the bottom of the tank mat or ringwall foundation, whichever is deeper. The geogrid should have a minimum ultimate strength of 1,500 lb/ft in machine and cross-machine direction. After sub-excavation, we anticipate foundation settlement of less than 6 inches.

2. Foundations should be constructed on properly placed fill as recommended in the SUBEXCAVATION FILL section below.

3. For areas where subexcavation is performed, foundations can be designed for a maximum allowable soil pressure of 3,000 psf.

5700 East Evans Avenue , Denver , CO 80222 1 525 B l ake Aven u e , G l e nw oo d Spr in gs , CO 81601

570 Turn e r Drive , S uit eD, Durango, CO 8 1303

Additional Geotechnical Recommendations Middle Fork Compressor Station

Project No. 210-187

4. Resistance to sliding at the bottom of the ringwall foundation and spread footing can be calculated based on a coefficient of friction of 0.40. Passive pressure against the side of the wall and footing can also be considered for the sliding resistance if foundation soils are properly compacted. Passive pressure can be estimated based on an equivalent fluid density of 375 pcf.

5. The soils below foundations should be protected from freezing. We recommend the bottom of foundations be constructed at least 36 inches below proposed grade.

6. The base of the subexcavation and all foundation excavations should be observed by a representative of the geotechnical engineer prior to the placement of fill or concrete.

Pipe Racks, VDU Vessel and Containment Walls 1. Based on foundation loads provided, we estimated foundation settlement on the

order of 1 to 3 inches for foundations placed on the existing fill and soft soils. Provided these movements can be tolerated by the proposed structures, shallow foundations can be designed for a maximum allowable soil pressure of 1500 psf. If higher foundation loads are planned or estimated settlement cannot be tolerated, we recommend subexcavation be performed as recommended above.

2. For pipe rack foundations, drilled friction pier foundations can be used to support pipe and platform legs. Piers should have a minimum length of 10 feet, otherwise, all other recommendations provided in the aforementioned report could be used for design.

3. Resistance to sliding at the bottom of the ringwall foundation and spread footing can be calculated based on a coefficient of friction of 0.30. Passive pressure against the side of the wall and footing can also be considered for the sliding resistance if foundation soils are properly compacted. Passive pressure can be estimated based on an equivalent fluid density of 300 pcf.

4. The soils below foundations should be protected from freezing. We recommend the bottom of foundations be constructed at least 36 inches below proposed grade.

5. The base of all foundation excavations should be observed by a representative of the geotechnical engineer prior to the placement of concrete.

SUBEXCAVATION FILL The on-site soils free of organic matter, debris, deleterious material and rocks larger

than 6 inches can be used in fills provided the materials meet the specification in the table below. Topsoil is not recommended for fill. Processing of on-site soils and/or import material may be required. Import material should also meet the specification below. Fill should be placed in thin, loose lifts of 8 inches thick or less. Fill should be placed at a moisture content within 2 percent of optimum moisture and compacted to at least 95 percent of maximum standard Proctor dry density (ASTM D 698). We recommend earthen berms be placed according to the specifications above and be constructed with side slopes no steeper than

2

Additional Geotechnical Recommendations Middle Fork Compressor Station

Project No. 210·167

2H:1V. Asbestos was encountered in our original investigation. Caution, notification to officials and on-site monitoring would be advised during excavation. Placement and compaction of fill should be observed and tested by a representative of a geotechnical engineer.

Sieve Size Percent Passing 6" 100 4" 95-100 1" 65-100

No.4 30-100 No. 200 5-30

'L1qu1d hm1t less than 35 and plasticity index less than 11.

LATERAL EARTH PRESSURE Retaining walls should be designed to resist lateral earth pressure. Walls can be

designed using an equivalent fluid density of 45 pel. This equivalent fluid density assumes a horizontal, on-site material backfill meeting the specifications above. This value assumed the backfill materials are not saturated. Wall designs should consider the influence of surcharge loading such as traffic, construction equipment and/or sloping backfill.

Retaining walls should be constructed with a drainage system to drain away any excess water immediately behind the wall. The drainage system may consist of free-draining gravel and/or weep holes are commonly used for wall drainage.

If you have questions or require additional information, please call.

Respectfully Submitted,

YEH AND ASSOCIATES, INC.

Keith E. Asay Staff Engineer

Cc: Mr. Drew Mathies, E. I. Project Engineer ZAP Engineering 12567 W. Cedar Drive, Suite 210 Lakewood, Colorado 80228

3

Reviewed By:

Richard D. Johnson, P.E. Northwest Regional Manager

Geotechnical Investigation

Middle Fork Compressor Station North Parachute Ranch 10652 County Road 215

Gar1ield County, Colorado

Project No. 210-187 December 2, 2010

Prepared for:

Mr. Jeff Schaefer EnCana Oil & Gas (USA), Inc.

2717 Garfield County Road 215 Parachute, Colorado 81635

Prepared by:

Yeh and Associates, Inc. 0170 Mel Ray Road

Glenwood Springs, Colorado 81601 Phone: 970-384-15 00

Fax: 970-384-1501

Middle Fork Compressor Station Project No. 210-187

TABLE OF CONTENTS

PURPOSE AND SCOPE ...................................................................................... 1

PROPOSED CONSTRUCTION ............................................................................ 1

SITE CONDITIONS .............................................................................................. 1

GEOLOGIC CONDITIONS ................................................................................... 2

SUBSURFACE CONDITIONS .............................................................................. 2

SEISMIC CLASSIFICATION ................................................................................. 4

SITE DEVELOPMENT .......................................................................................... 4

FOUNDATION RECOMMENDATIONS ................................................................ 4

Drilled Friction Piers ................................................................................... 5

Helical Piers or Micropiles .......................................................................... 5

SURFACE DRAINAGE ......................................................................................... 6

WATER SOLUBLE SULFATE .............................................................................. 6

LIMITATIONS ....................................................................................................... 6

Figures

Approximate Test Hole Locations .................................................................................... 1 Test Hole Logs ............................................................................................................... 2-6 Test Hole Legend .............................................................................................................. 7

Appendices Laboratory Test Results .................................................................................................... A


PURPOSE AND SCOPE

This report presents the results of our geotechnical investigation for design and

construction of five new water tanks for EnCana Oil and Gas at the Middle Fork Compressor

Station in Garfield County, Colorado. The subsurface investigation was conducted to provide

recommendations for foundation design and construction of five new tank foundations at this

site. The site investigation consisted of reconnaissance and drilling of exploratory borings to

investigate subsurface conditions. EnCana Oil & Gas provided planned structure locations.

The exploratory drilling was observed by a representative of Yeh and Associates. Samples

obtained during the field exploration were examined by the project personnel and representative

samples were subjected to laboratory testing to determine the engineering characteristics of

materials encountered.

Based on our investigation, Yeh and Associates completed an engineering analysis of

the subsurface conditions. This report summarizes our field investigation, the results of our

analysis, and our conclusions and recommendations based on the proposed construction, site

reconnaissance, subsurface investigation and results of the laboratory testing.

PROPOSED CONSTRUCTION

We understand the proposed construction will consist of five treated water tanks with an

associated containment area. The proposed tanks are planned for 75,000 barrels and will be

116 feet in diameter and 40 feet high. Potentially, the tanks may be reduced in diameter and

may be taller. The proposed site plan and approximate test hole locations are presented on

Figure 1.

SITE CONDITIONS

The Middle Fork Compressor Station was located approximately 11 miles north of

Interstate 70 on Garfield County Road 215 (Parachute, Colorado). The site address was posted

as 10652 County Road 215. Middle Fork Compressor Station is a fully operational gas

gathering facility complete with structures and equipment necessary for natural gas production,

collection and distribution. The proposed site is located west of the current treated pond in the

current storage, construction, welding/fabrication yard. The site slopes gently down to the south

at a grade of less than 5 percent and is approximately 5793 feet above mean sea level. The

site is surrounded by existing structures with exception to the south which is bounded by the

1


continuation of County Road 215 which parallels East Fork. Vegetation is native scrub, pinyon

and juniper trees. Access to the site was gained on an unimproved road.

GEOLOGIC CONDITIONS

The project area was located in the Roan Plateau area of the northern Piceance Basin of

western Colorado, a major gas production area made up of high plateaus, mesas, ridges and

deep valleys. The site was on the valley floor of the Parachute Creek drainage, near of the

confluence of East Fork and Middle Fork of Parachute Creek, and approximately one-fourth mile

northeast of the confluence of West Fork and Parachute Creek. The site was bounded to the

north by the southwest edge of Long Ridge and to the south by Lindauer Point. The proposed

building site was located on commercial/industrial property that is the location of the Encana Oil

and Gas Middle Fork Compressor Station.

The project area was located on artificial fill and alluvium, which included material

ranging in size from clay and silt to gravel. Underlying the site and in the hillsides in all

directions from the site, was the gray shale and marlstone of the Tertiary age Garden Gulch

Member of the Green River Formation.

SUBSURFACE CONDITIONS

Subsurface conditions were investigated by drilling 14 holes on a north-south grid line

(Test Holes TH-1 through TH-14) as per the client's request, in an effort to investigate potential

fill, trash and debris. The client provided the grid line location. Five of these holes (Test Holes

TH-3, TH-6, TH-8, TH-11 and TH-14) were deepened and used for tank foundation investigation

as well as test holes TH-15 through TH-19. Yeh and Associates personnel selected which

holes were to be deepened as well as the locations of the additional 5 test holes. Test holes

TH-1 through TH-6, TH-18 and TH-19 were drilled for two future tanks and test holes TH-7

through TH-17 were drilled for three proposed tanks. The approximate locations of exploratory

test holes are presented on Figure 1. All test holes were advanced using a CME-55 truck

mounted drill rig with 4-inch continuous flight auger to pre-determined depths where a modified

California or split spoon sampler was used to record blow counts and obtain samples.

To perform the modified California penetration resistance test, a 2.0-inch inside diameter

sampler was seated at the bottom of the test hole, then driven up to 12 inches with blows of an

standard hammer weighing 140 pounds and falling a distance of 30 inches. The number of

2


blows (Blow Count) required to drive the sampler 12 inches or a fraction thereof, constitutes the

N-value. The N-value, when properly evaluated, is an index of the consistency or relative

density of the material tested. The split spoon sampler was used in the same manner but with a

1.5-inch inside diameter. The results are shown on Figures 2 through 6.

Existing fill was encountered in the majority of the test hole borings. The age of the fill

made differentiation from naturally deposited soils difficult. The fill consisted of sand, gravel and

silt material. Debris, such as ceramic pieces and metal was encountered in the fill in test holes

TH-19 and TH-25 at depths of 9 and 2 feet, respectively. Asbestos was also encountered in the

fill in test hole TH-28 within the upper 3 feet. Further potential deleterious material and debris

could be encountered upon excavation, but due to the spacing and location of the test holes,

was not observed at other test hole locations. We believe that the fill was placed in an

uncontrolled manner.

Generally, the subsoils beneath the fill consisted of sand, gravel, silt and clay. Bedrock

was encountered in test holes TH-14 and TH-15 at depths of 33.5 and 37.5 feet, respectively.

Four fill samples tested had 10 to 54 percent fines (material passing the No. 200 sieve).

Atterberg limit testing indicated liquid limits of non-liquid to 40 percent and plastic indices of non

plastic to 23 percent. Five additional fill samples exhibited low collapse (-0.2 to -0.4 percent)

when wetted under an applied load of 1,000 psf. Twelve sand samples tested had 8 to 33

percent fines, liquid limits of non-liquid to 46 percent and plastic indices of non-plastic to 16

percent. Four additional sand samples exhibited low collapse (-0.2 to -0.5 percent) when wetted

under an applied load of 1,000 psf. Six gravel samples tested had 8 to 10 percent fines, liquid

limits of non-liquid to 35 percent and plastic indices of non-plastic to 14 percent. Four silt and

clay samples tested had 26 to 65 percent fines, liquid limits of 43 to 47 percent and plastic

indices of 15 to 18 percent. Two additional silt samples exhibited low collapse of -0.3 percent

when wetted under an applied load of 1,000 psf. One sandstone bedrock sample tested had 45

percent fines, a liquid limit of 34 percent and a plastic index of 16 percent. The fill was medium

dense to dense and stiff to very stiff and classified as SP, SM, SC, SW-SM, ML and CL

according to the Unified Soil Classification System (USGS). The sand and gravel was very

loose to very dense and classified as SP, SW, SP-SM, SW-SM, SM, SC, GP, GW, GP-GM,

GW-GM. The silt and clay was medium stiff to stiff and classified as a ML and CL. The

laboratory test results are presented in Appendix A and are summarized in the Summary of

Laboratory Test Results table.

3


Groundwater was encountered at depths of 16 to 20 feet during this investigation

throughout the site. Subsoils were slightly moist to wet. Variations in groundwater conditions

may occur seasonally. The magnitude of the variation will be largely dependent upon the

amount of spring snowmelt, duration and intensity of precipitation, site grading changes, and the

surface and subsurface drainage characteristics of the surrounding area. Perched water tables

may be present, but were not encountered in these borings.

SEISMIC CLASSIFICATION

The 2006 IBC seismic classification is based on extrapolation of test hole data to depths

explored and our experience in the area. We consider the project site to be classified as a

seismic site Class D. Quantitative, down-hole, shear wave velocity testing could result in a

different site classification. Drilling and installation of casing to a depth of at least 100 feet is

necessary to perform this testing. If desired, we can provide a proposal for performing this

testing.

SITE DEVELOPMENT

We believe fills and cuts should be minable. Areas to receive fill should be stripped of

vegetation, organic soils and debris. The on-site soils free of organic matter, debris and rocks

larger than 6 inches can be used in fills. Fill should be placed in thin, loose lifts of 8 inches thick

or less. Clay soils should be moisture conditioned to 0 to 3 percent above optimum moisture

content and compacted to at least 95 percent of maximum standard Proctor dry density (ASTM

D 698). Granular soils should be placed at a moisture content within 2 percent of optimum

moisture. Placement and compaction of fill should be observed and tested by a representative

of a geotechnical engineer.

FOUNDATION RECOMMENDATIONS

The fill and natural soils exhibited low compression during laboratory testing.

Additionally, we believe the fill was placed in an uncontrolled manner. Due to the planned

weight of the structures and existing conditions, we believe the proposed tanks should be

supported on a deep foundation such as drilled friction piers, micropiles or helical piers.

Typically, micropiles and helical piers are installed by a specialty design/build contractor.

Recommended design and construction criteria for drilled friction piers, micropiles or helical

piers are presented below.

4


Drilled Friction Piers

1. Piers should be designed for an allowable end pressure of 15,000 psi and an allowable skin friction of 1,500 psi for the portion embedded in natural clay, sand and/or gravel. We recommend the upper 5 feet of the pier be ignored for support.

2. Piers should have a minimum length of 20 feet and a minimum diameter of 18 inches.

3. For lateral loading analysis using LPILE program, the following parameters may be used:

Friction Horizontil Modulus Total Saturated

Material Soil

Angle,~ Cohesion, ofSubgrade

Unit Unit Model

(deg) c(psl)

Reaction, k, (poi) 850 w~~~~·Y w~~~·Y Sand and

Gravel above Sand 32 0 100 - 130 135 oroundwater

Sand and Gravel below Sand 32 0 70 - 130 135 groundwater

4. The mm1mum spacing requirements between piers should be three diameters from center to center. For lateral loading, recommended P multipliers are 0.5 for tangent piers increasing linearly to 1.0 for piers placed at 3 diameters or greater. Additional capacity reduction factors can be provided if required for conditions other than those anticipated.

5. Groundwater was encountered during our investigation. Relatively deep piers may encounter groundwater. Casing of friction piers should not be performed unless piers were designed as end bearing only. Tremie placement of concrete in pier holes may be necessary.

6. A representative of the soil engineer should observe pier installation on a fulltime basis.

Helical Piers or Micropi/es

As an alternative, a deep foundation system such as helical piers or micropiles could be

utilized for tank foundations. We believe that either of these systems could penetrate the

existing fill and softer overburden soils and be founded into the firmer soils. Helical piers and

micropiles could be designed for working loads on the order of 20 to 60 kips per pile. Typically,

these systems are designed and installed by a specialty contractor. General recommendations

for design and construction of micropiles and helical piers are presented below.

5


1. The structural engineer should determine pier or micropile locations and load requirements for all piers or micropiles. This information should be provided to a specialty design/build contractor to provide shop drawings for the piers or micropiles. Based on our observations, we do not believe downdrag would induce additional loading on the foundation. Therefore, we do not believe the foundation design needs to account for additionalloadi ng due to downdrag.

2. Piers or micropiles could penetrate through the existing fill and softer overburden soils and be founded within firmer soils. We recommend a minimum pier or pile length of 20 feet. We recommend piers or piles be founded below the existing fill. Target depths for piers and top of bond zone for micropiles would need to be determined by the designer based on loading. In general, soils generally become denser and stiffer with depth.

3. A representative of the geotechnical engineer should observe pier or micropile installation.

SURFACE DRAINAGE

Surface drainage is crucial to the performance of foundations and flatwork. We

recommend the ground surface surrounding structures be sloped to drain away. We

recommend a slope of at least 6 inches in the first 10 feet for gravel areas and a minimum slope

of 1 percent for paved areas. Backfill around foundations should be moisture conditioned and

compacted as recommended in the SITE DEVELOPMENT section.

WATER SOLUBLE SULFATE

We measured water soluble sulfate concentrations of 0.014 and 0.028 percent for two

samples of the subsoils. Based laboratory test results, we anticipate a Class 0 exposure for

concrete due to the presence of water-soluble sulfate. Based on ACI 201.2R-01, "Guide to

Durable Concrete," concentrations between 0.0 and 0.1 percent represent Class 0 exposure

(negligible/low). For cast-in-place structures such as foundations, pavements placed on onsite

soils and grout for micropiles, ACI recommends ASTM C 150 Type II or equivalent be used for

improvements at this site. Structural fill and aggregate base course are assumed to have Class

0 exposure or no effect on concrete.

LIMITATIONS

The analyses and recommendations presented in this report are based upon our data

obtained from the test holes at the indicated locations, field observations, laboratory testing, our

understanding of the proposed construction and other information discussed in this report. It is

6


possible that subsurface conditions may vary between or beyond the points explored. The

nature and extent of such variations may not become evident until construction. If variations

appear, we should be contacted immediately so we can review our report in light of the

variations and provide supplemental recommendations as necessary. We should also review

the report if the scope of the proposed construction, including the proposed loads, finished

elevations or structure locations change from those described in this report. The conclusions

and recommendations contained in this report shall not be considered valid unless Yeh and

Associates reviews the changes and either verifies or modifies the conclusions of this report in

writing.

The scope of services for this project included preliminary environmental study of the fill

and debris for asbestos, only. Although our investigation did identify asbestos at one location,

the owner should undertake additional studies to determine the extent of the contamination.

The report was prepared in substantial accordance with the generally accepted

standards of practice for geotechnical engineering as exist in the site area at the time of our

investigation. No warranties, express or implied, are intended or made.

Respectfully Submitted,

YEH AND ASSOCIATES, INC.

Keith E. Asay Staff Engineer

Reviewed By:

Richard D. Johnson, P.E. Senior Geotechnical Engineer

7

LEGEND:

T~-1 Indicates approximate location of exploratory test hole

Project No. 210-187 SCALE: 1" = 100'

Approximate Test Hole Location

Figure 1

)

)

)

0

~ g ~ ~

~ 0

§ ~ ~ N

g .t:: c. (I)

0

TH-01 Grid. Line

0•·

1719

5•· '-~1? ..

10' ...... )·.!"· .~?m ......... .

15•·· ................. .

30•··

35•·

40• ......................... .

45•··

TH-02 Grid Line/Future South Tank

20/12

.1.¥.1.~

~~'.1.~

9112 '9112'

~28112

TH-19 TH-03 Future South Tank Future South Tank

. ·············· ························································································f•.•-:1·

.... ··················································~-~}!-.

TH-04 Grid Line

.. 0

24112

-~,-~ ....................... 15

8/12 ·•10

15112 15

20

·•25

30

35

40

··········•45

~--······································································· ··································································································································-~

~~------------------------------------------------------------------~------------------------------------------------------------------~

iJ~ ;L~~~~~~~------------------------------------------------------_J~P~ro~~e~ct:!N~u~m!be~r:~2~1~0~-~18~7~--------------------------------------~F~ig~u~r~e~N~o~-~2~ ~

YEH AND ASSOCIATES, INC. GEOTECHNICAL ENGINEERING CONSULTANTS

Middle Fork Compressor Station

0

~ b ~ a ~

§ ~

§ ~ ~ N

g .<::: a. (J)

0

TH-18 TH-05 TH-06 Future North Tank Grid Line/Future North Tank Future North Tank

0

24/12 37/10 3911

1 •• ?~,? ... --~~1? .. . .. ?9/1~1 5

--~~~?.. . ... _,:<~m .. . .. ?~n~ 10

12112 ..?9!~~ 15

'·. 9!1?. ... ?9!1~ 20

,, .?!1? .. . .. ~!~ 25

--~~?.. . ............... . '·. ??!!ft 30

35

'·. ?9!~. ············• 40

4~·· 45

5 ················· ·············· ~

~.~------------------------------------------------------------------------,-----------------------------------------------------------------------~

iJ~ ~;L__:::~~::~::=-----------------------------------------------------------~P~ro~je=ct~N~u~m~b=e~r:~2~1~0~-~1~8~7 __________________________________________ _cF~ig~u_re __ N_o_._3 __



~ b

~ § § ~ 6 ~

g .c 15. ., 0

TH~7 Grid Une/South Tank

······lh'f.-J..~F ....

. . . ·!ii:t1·. ')9!}? ..

2· . . . . rLLLJ .. ')~m ..

2

3••···

3, ..

4••··

4~··

5••··

TH-17 South Tank

14112

'·. ~.5!!?-..

TH-08 South Tank

'· .~!?.. . ......... ··········~ ,,1,1/:1?-..

'·. ),:;;.')? .• . ::t:WAl· 1112 ...

,,,;3!1? .. . .... W.+-'. m! ...

'·. ).4!)?-.. .. 1?19 ..

'·. ?.QI? ........................................... ~ •. "."!~

5010

TH-09 Grid line/South Tank

15112

. _7/}?...

..1¥.1?...

.. 1.~.1-~

0

5

10

15

20

25

30

35

40

45

....... 50

~~------------------------------------------------------------------,--------------------------------------------------------------------J

iJ~ ~il_~~~~::~::------------------------------------------------------~P~r~o~je~ct~N~u~m~b=er~:~2~1~~:1~8~7----------------------------------------~F~ig~u~re~N~o~·~4-



0

~

I ~ ii ~ ;;

g .<::: 1i (J)

Cl

··-·-. ·--··--·-··------

TH-16 TH-10 TH-11 Center Tank Grid Une/CenterTank Grid Une/CenterTank

0

14112 21/12 21/1

11/12 11/12 1011- 5

5/12 11/12 1211 ... 10

1/12 22/12 ·--~~~-1 15

2· 5112 1011- 20

2 26/12

25

3 2416

30

3~------------------------------------------------------------------------------~ 35

~~------------------------------------,----------------------------------------------

i l'j ~ a Project Number: 210-187 Figure No. 5 ~



0

~ b ~ 3 ~

~ ~

§ ~ 6 ~

g .<:: c. Q)

0

4

TH-12 TH-13 TH-14 TH-15 Center Tank Grid Une/North Tank North Tank North Tank

~ m I; m m I· 16112 F 31112 13112

20112 r-: 13/12 c-: 13112 • 5

4112 10/12 10

22112 4/12 15

15/12 13112 20

.. Sf~~- ............ · · · · · · · · ·······.I 25

7/12 30

························• 35

~ --··- 40

~~--------------------------------------------------------------~------------------------------------------------------------~

iJ~ ;l_~~~~~~~--------------------------------------------------_L~Pro~je~ct~N~u~mb~e~r:~21~~~18~7~----------------------------------~F~ig~u~r~e~N=o~-~6~



l 'jYEH AND ASSOCIATES, INC. Project: Middle Fork Compressor Station ... GEOTECHNICAL ENGINEERING CONSULTANTS Project Number: 21 Q-187

Legend for Symbols Used on Test Hole Logs

Sample Types

D Modified California Sampler. The symbol 20/12 indicates that 20 blows from a 140 pound hammer falling 30 inches was used to drive 2-inch I. D. sampler 12 inches .

•

Split Spoon Sampler. The symbol9/12 indicates that 9 blows from a 140 pound hammer falling 30 inches was used to drive 1.5-inch 1.0. sampler 12 inches.

~ Indicates bulk sample.

Other Symbols 5l Indicates approximate ground water level

at time of drilling.

Indicates approximate ground water level 1 day after drilling.

Soil Lithology

~ Concrete

Fill, gravel, base coarse (GP).

Fill, sand, clean, silty, clayey, occasional bedrock fragments, occasional gravels, occasional debris and asbestos, medium dense to dense, slightly moist to moist, gray, brown, dark brown, rust (SP, SM, SC, SW-SM).

Fill, silt, slightly sandy, occasional bedrock fragments, occasional gravels, medium stiff to very stiff, moist to very moist, brown, dark brown (ML).

Fill, clay, slightly sandy, silty, occasional bedrock fragments, occasional gravels, stiff, moist to very moist, brown, dark brown (CL).

Bedrock Lithology

D Bedrock sandstone, slighty silty, hard, slightly moist, gray.

~ Shale bedrock, silty, hard, slightly moist, gray.

Notes:

LJ [0]

~

Sand, poorly to well graded with silt, occasional bedrock fragments, occasional gravel, medium dense to very dense, slightly moist to wet, gray, brown, rust (SP, SW, SP-SM, SW-SM).

Sand, silty, occasional bedrock fragments, occasional gravel, loose to medium dense, slightly moist to wet, gra'f brown (SM).

Sand, clayey, occasional bedrock fragments, occasional gravel, very loose to medium dense, slightly moist to wet, gray, brown (SC).

Gravel, poorly to well graded with silt, occasional bedrocl fragments, medium dense to very dense, wet, gray, brow (GP, GW, GP-GM, GW-GM).

Silt. slightly sandy, stiff, wet. brown, dark brown (ML).

Clay, slightly sandy, medium stiff, wet, brown, dark brow (CL).

1. Test holes were drilled on October 27, 28 and 29, 2010 using 4-inch continuous flight auger. 2. Test hole descriptions are subject to explanations contained in this report.

Figure No.7

APPENDIX A

LABORATORY TEST RESULTS

Sieve Analysis Hydrometer Analysis

Sieve Opening in Inches I U.S. Standard Sieves Size of Particles in mm

12" 6" 3" 2" 1" 314" 112" 318" 4 8 10 16 30 40 50 100 200 Sieve % Size Passing

100

I 3" -I

90 I , 2%" I -

80 2" -

70 1 %" -I , , I 1" -., 60

c iii %" 100 II) , ..

50 0.. - I %" 93 c I .. ' ~ 40 I .. I %· 91 0.. I

30 #4 80

20 #10 69

#40 50 10

, , #200 27 0

1000 100 10 1 0.1 0.01 Particle Size (mm)

Gravel(%) I

20 LL 34 Project Name: Middle Fork Compressor

I~ Y eh & Associates~ Inc. Station

I

Geotechnical Engineering Consultants Sand(%) 53 PL 24 SampleiD: TH-2

I Sample

SIEVE ANALYSIS Fines(%) 27 PI 10 15

Depth (ft.): Drawn By: MA Project No.: 210- 187 Sample Checked By: KA ~scriction:

Sand, silty (SM) Figure No.: A-1

Revised 04/L J4

- -



12" , .. 3'' , .. 1" 314" 112" 318" 4 8 10 16 30 40 50 100 200 Sieve %

100 Size Passin

3" -90

2%" I -' I

80 I 2" -' I ,

1 %" 70 ' -' '

1" 100

"' 60 c 'iii %" 90 .. "' c. 50 - %" 84 c I I .. I:! 40 .. I %" 80 c.

I I

30 I #4 69 I

I

I

#10 54 20 ' ' I

' ' #40 35

10 ' ' I I #200 26 I

0 '

1000 100 10 1 0.1 0.01 Particle Size (mm)

Gravel(%) 31 LL 37 Project Name: Middle Fork Compressor

I~ Y eh & Associates, Inc. Station Geo1echnical Engineering Consultants

Sand(%) 43 PL 22 Sample ID: TH-3

Sample SIEVE ANALYSIS Fines(%) 26 PI 15 4

Deoth (ft.): Drawn By: SW Project No.: 210-187 Sample Checked By: KA

Description: Sand, clayey (SC) Figure No.: A-2

Revised 04/22/2004



12" .. 3" 2" 1" 3/4" 112" 318" 4 8 10 16 30 40 50 100 200 Sieve % Size Passing

100 ' ' 3" -I

90 ' 2%" -

'

80 '

2" -'

' ' 1 %" 70 -

'

' I

I 1" -"' 60 c

"iii "' %" -..

50 D.. - %" -c .. " ~ 40 .. %" 100 D..

30 #4 99

20 #10 92

#40 74 10

#200 65 0

1000 100 10 1 0.1 0.01 Particle Size (mm)

Gravel(%) I 1 LL 46 Project Name: Middle Fork Compressor

I~ Y eh & Associates, Inc. Station

I

Geotechnical Engineering Consultants Sand(%) 34 PL 28 Sample ID: TH-3

I

Sample SIEVE ANALYSIS

Fines(%) 65 PI 18 25-25.5 Depth (ft.): Drawn By: MA Project No.: 210- 187

Sample Checked By: KA Description:

Silt, sandy (ML) Date: 12/01/10 Figure No.: A-3

Revised 04/~ J4



12" 6" , .. 2" 1" 314" 112" 318" 4 8 10 16 30 40 50 100 200 Sieve % Size Passing

100 ' ' 3" -'

90 I I

I I 2%" -I

80 I 2" -I I

70 1 %" 100 I

I 1" 91 "' 60 '

I c ' I ·;;; I %" 87 "' I .. I I D.. 50 I I - I ' %" 75 c ' ' ., I I

" ~ 40 I I ., I I %" 70 D.. I I I I I I

30 I I #4 52 ' I I

' I I

' I #10 33 20 ' ' I

I

' I I #40 17

10 I I I

#200 9 0

1000 100 10 1 0.1 0.01 Particle Size (mm)

Gravel(%) I

48 LL NV Project Name: Middle Fork Compressor

I~ Y eh & Associates~ Inc. Station Geotechnical Engineering Consultants

Sand(%) 43 PL NP Sample ID: TH-6


Fines(%) 9 PI NP 24 Depth (ft.}: Drawn By: MA Project No.: 210-187

Sample Checked By: KA Descriotion:

Gravel, slightly silty (GP-GM) Figure No.: A-4

Revised 04/27/2004



12" •• 3" 2" 1M 3/4" 112" 318" 4 8 10 16 30 40 50 100 200 Sieve % Size Passing

100 '

' 3" -90 '

' 2%" -

80 I 2" I -

' ' 1 %" 70 ! -' ' ' ' 1" -

Cl 60 I

c ·;;; %" 100 .. .. D. 50 - %" 97 c "' ~ 40 "' %" 95 D. ' '

30 I #4 79

' '

20 ' #10 64

' ' I #40 38 10 '

' '

#200 17 0

1000 100 10 1 0.1 0.01 Particle Size (mm)

Gravel(%) I


I~ Y eh & Associates~ Inc. Stations Geotechnical Engineering Consultants



Fines(%) 17 PI 11 15- 19 Deoth (ft.l: Drawn By: MA Project No.: 210-187


Sand, clayey (SC) Figure No.: A-5

Revised 04/: )4



12" IS' 3" 2" 1" 314" 112"~ 4 8 10 16 30 40 50 100 200 Sieve % Size Passing

100 ' ' 3" -"

90 2 y, .. -

I I

80 ' 2" I -I ' ' '

I 1 y, .. 70 I I -

I I

1" -"' 60 c iii %" 100 .. .. D. 50 - y, .. 96 c ., " ~ 40 .,

%" 92 D.

30 #4 83

20 #10 71

#40 53 10

#200 21 0

1000 100 10 1 0.1 0.01 Particle Size (mm)


I~ Y eh & Associates, Inc. Station Geotechnical Engineering Consultants



Fines(%) 21 PI 11 6-9 Depth (ft.): Drawn By: MA Project No.: 210-187



Revised 04/27/2004



12" s·· s·· , .. 1" 314" 112" 318" 4 8 10 16 30 40 50 100 200 Sieve % Size Passin~

100 3" -

90 2 y, .. -

80 2" -

70 1 y, .. -

1" -"' 60 c 'iii %" 100 ., .. a. 50 - y, .. 98 c "' !:! 40 "' %" 95 a.

' '

30 #4 84 ' ' ' ' ' #10 69 20 ' '

'

#40 49 10

#200 30 0

1000 100 10 1 0.1 0.01 Particle Size (mm)



Sand(%) 54 PL 23 SampleiD: TH-8


Fines(%) 30 PI 14 15- 19 ! Depth (ft.): Drawn By: MA Project No.: 210-187



Revised 04/: )4.

-



12" 6" 3" 2" 1" 314~ 112" 318" 4 8 10 16 3040 50 100 200 Sieve %

100 Size Passi~

3" -90

2%" -80 2" -

70 1 %" 100

1" 94 ., 60 c ·;;;

%" 87 .. .. D.. 50 - %" 77 c .. " ~ 40 .. %" 73 D..

30 #4 53 I

'

20 #10 34

#40 19 10

#200 9 0

1000 100 10 1 0.1 0.01 Particle Size (mm)

Gravel(%) 47 LL NL Project Name: Middle Fork Compressor

I~ Y eh & Associates~ Inc. Station Geotechnical Engineering Consultants I Sand(%) 44 PL NP Sample ID: TH-8

Sample SIEVE ANALYSIS Fines(%) 9 PI NP 29

Depth (fl.): Drawn By: MA Project No.: 210- 187 Sample Checked By: KA Description:

Gravel, slightly silty (GW-GM) Figure No.: A-8

Revised 04/27/2004



12" , .. , .. 2" 1~ 3/4" 112~ 318" 4 8 10 16 30 40 50 100 200 Sieve % Size Passing

100 ' ' ' I 3" -' '

' 90

2 y, .. -

80 2" -

70 1 y, .. -

1" -

"' 60 c 'iii %" 100 .. .. c.. 50 - y, .. 97 c ., " ~ 40 .,

%" 92 c.. '

30 ' #4 82 '

'

20 #10 67

'

I #40 40 10 I

#200 13 0

1000 100 10 1 0.1 0.01 Particle Size (mm)





Fines(%) 13 PI 12 10- 14 Deoth (ft. l: Drawn By: MA Project No.: 210- 187



Revised 04/: )4



12" 6" , .. , .. 1" 3/4" 112" 318" 4 8 10 16 30 40 50 100 200 Sieve % Size Passirl£ 100

'

' 3" -' ' 90 ' ' 2%" ' -' I

' 80 I ' 2" ' ' -

I

70 I ' 1 %" -

: 1" 100 Cl 60 c

' ·;;; %" 100 .. .. I ' n. so ' - ' %" 91 c I I

' .. I I I ~ 40 ' .. I %" 85 n.

' I

30 ' #4 62 ' ' '

20 ' #10 42

' I ' #40 26

10 I

' ' #200 10

0

1000 100 10 1 0.1 0.01 Particle Size (mm)



Sand(%) 52 PL NP SampleiD: TH-12


Depth (ft. l: Drawn By: sw Project No.: 210-187 Sample Checked By: KA

Description: Fill, sand, silty (SM) Figure No.: A-10

Revised 0412212004



12" 6" 3" 2" 1" 314" 112" 318" 4 8 10 16 30 40 50 100 200 Sieve % Size Passi~

100 ' 3" -

90 2%" -

I

' ' 80 '' ' I 2" I I -

I I

1 Yz" 70 ' -I

1" -.. 60 c:

"iii %" -"' .. a. 50 I - I I %" -c: I I

' ., I I

l:! 40 I I

' ., I %" a. I -I

30 #4 99

20 #10 97

#40 93 10

#200 61 0 ' '

I

1000 100 10 1 0.1 0.01 Particle Size (mm)





Fines(%) 61 PI 18 9 Deeth (ft.): Drawn By: SW Project No.: 210-187


Clay, sandy (CL) Figure No.: A-11

Revised 04. 04



12" , .. 3'' 2" 1" 314" 1/2" 318" 4 8 10 16 30 40 50 100 200 Sieve % Size Passing

100 ' ' ' 3" -. '

' ' 90 ' '

• 2%" ' I -' ' I ' '

80 I ' ' 2" I ' I -' ' I

' ' 1 %" 70 I -;

' 1" -"' 60

' "' ·;;; I %" 100 .. ' ., ' 0.. 50 ' - ' %" 100 "' ' "' ' l:! 40 "' %" 98 0.. ' '

30 #4 87 I

'

I #10 72 20

'

' ' I I ' ' #40 41

10 ' ' ' ' I I

' #200 17 '

0 '

1000 100 10 1 0.1 0.01 Particle Size (mm)





Fines(%) 17 PI 12 15.5-18.5 Depth (ft.): Drawn By: MA Project No.: 210- 187



Revised 04/27/2004

------ ------- --- ------



12" , .. , .. 2"" 1M 314" 112" 3/S" 4 8 10 16 3040 50 100 200 Sieve % Size Passi~

100

3" -I I

90 2%" -

80 2" -

70 1 y., .. -' I

1" -"' 60 I ' ' ' c

' ' ·;;; ' %" 100 ., ' ..

D. 50 - y., .. 92 c "' I! 40 "' %" 85 D.

30 #4 71 '

' '

20 ' #10 54

I ' ' #40 37

10 ' I

I #200 15 0 '

1000 100 10 1 0.1 0.01 Particle Size (mm)

Gravel(%) I


I~ Y eh & Associates~ Inc. Station

I Geotechnical Engineering Consultants


I Sample

SIEVE ANALYSIS Fines(%) 15 PI 23 9

Depth (ft.): Drawn By: MA Project No.: 210- 187 Sample Checked By: KA

Description: Fill, sand, clayey (SC) Figure No.: A-13

Revised 04/; )4



12" 6" 3" 2" 1" 314" 112" 318" 4 8 10 16 30 40 50 100 200 Sieve % Size Passing

100 '

' 3" -

90 2 y, .. ' -

' I I I

80 ' ' 2" ' -' ' I

I

' 1 y, .. 100 70 I I I

I 1" 81

"' 60 ' ' c ' 'iii ' I %" 76 "' ' I .. I c.. 50 I - y, .. 65 c ' "' I! 40 I I

"' :y, .. 58 c.. I I

' 30 ' #4 44

I

20 #10 34

' #40 21 10

I

'

'

#200 10 0

1000 100 10 1 0.1 0.01 Particle Size (mm)





Fines(%) 10 PI 14 19 Depth (ft.): Drawn By: MA Project No.: 210- 187


Gravel, clayey (GC) Figure No.: A-14

Revised 04127/2004



12" 6'" 3" 2" 1" 314" 112" 318" 4 a 10 18 30 40 50 100 200 Sieve %

100 Size Passing

3" -90

2 y, .. -

80 2" -I

70 I 1 y, .. -' I

' I 1" 100

60 I

"' ' I c::

iii %" 97 ., .. D.. 50 I - y, .. 89 c:: ., " ~ 40 .,

%" 85 D..

30 #4 72

20 I #10 61

' #40 49 10

' #200 27 0 '

1000 100 10 1 0.1 0.01 Particle Size (mm)

Gravel(%) I


I~ Y eh & Associates, Inc. Station

I

Geotechnical Engineering Consultants Sand(%) 45 PL 23 Sample ID: TH-15

I


Fines(%) 27 PI 13 24 Depth (ft.): Drawn By: MA Project No.: 210-187



Revised 04/: )4



12" 6" 3" 2" 1" 314" 112" 318" 4 a 10 16 30 40 50 100 200 Sieve % Size Passing

100 '

' 3" -'

90 ' ' 2 '/:!" -I ' '

80 ' ' '

2" -I I I I

' ' '

1 %" 70 ' -' ' I I

I

' 1" -C) 60 ' ' ' ' c

' I "iii ' ' %" -., I I ..

D.. 50 ' - I I %" -c "' I I ::! 40 I

"' ' :y. .. 100 D.. I

' ' I

30 ' #4 93 I '

' ' ' I ' I #10 80 20 I

I ' ' #40 62

10 I

I I #200 45 I

0 '

1000 100 10 1 0.1 0.01 Particle Size (mm)

Gravel(%) I


I~ Y eh & Associates2 Inc. Station

I

Geotechnical Engineering Consultants Sand(%) 48 PL 18 SampleiD: TH-15

I Sample

SIEVE ANALYSIS Fines(%) 45 PI 16 37.5- 39

Depth (ft.): Drawn By: MA Project No.: 210-187 Sample Checked By: Keith Description:

Sandstone Bedrock Figure No.: A-16

Revised 04/27/2004



12" 6" 3" 2" 1" 3/4" 112" 318" 4 8 10 16 30 40 50 100 200 Sieve %

100 Size Passin~

3" -90

2%" -

80 2" -

' 1 %" 70 -I

I 1" -"' 60 ' I c

' iii %" 100 II) i .. 50 I 0.. - Yz" 78 c ..

!! 40 .. ' %" 70 0.. '

30 #4 44

20 #10 27

' #40 18 10 '' ' I •

' ' ' I #200 10 '' 0 ' '

1000 100 10 1 0.1 0.01 Particle Size (mm)





Fines(%) 10 PI NP 24 Depth (ft.\: Drawn By: sw Project No.: 210-187


Gravel, slightly silty (GP-GM) Figure No.: A-17

Revised 04. 04



12" ... 3" 2" 1" 3/4" 112" 318" 4 8 10 16 30 40 50 100 200 Sieve % Size Passin~

100 ' ' 3" -

90 2%" -

I

80 '

2" -I

70 1 %" -I

I

1" -"' 60 h c I ·;;; I %." 100 Ill

' .. 50 I 11.

' - ' %" 86 c I:

"' ' ' !:! 40 ' ' "' ' ' %" 83 11.

I

30 I I ' #4 72 I

' I ' I

#10 55 20 I ' ' ' ' '

' #40 39 I I '

10 I '

' ' ' ' ' #200 21 '

0 '

1000 100 10 1 0.1 O.Q1 Particle Size (mm)





Fines(%) 21 PI NP 4 Depth (ft.): Drawn By: sw Project No.: 210-187


Fill, sand, silty (SM) Figure No.: A-18

Revised 0412212004



12" S' 3" 2" 1" 3/4" 1/2" 318" 4 8 10 16 30 40 50 100 200 Sieve % Size Passing

100 3" -

90 2%" -

80 '

2" -'

70 1 %" -' ' ' ' 1" -

"' 60 '

"' ' "iii %" 100 .. .. D.. 50 - %" 96 "' "' I:! 40 "' %" 88 D..

30 #4 75

20 #10 61

#40 32 10

' ' #200 10 '

0 '

1000 100 10 1 0.1 0.01 Particle Size (mm)





Fines(%) 10 PI 11 15- 17.5 Depth (ft.): Drawn By: MA Project No.: 210-187


Sand, slightly silty (SW-SM) Figure No.: A-19

Revised 04/; )4

~



12" 6'' 3" 2" 1" 3/4" 112" 318" 4 8 10 16 30 40 50 100 200 Sieve % Size Passi~ 100

' I

' 3" -

' I

90 ' ' 2%" ' ' -

' ' ' '

80 ' ' '

2" -' I

'

70 ' '

1 %" -' ' 1" -

"' 60 I

c '

·;;; %" 100 1/)

' "' .h ' ll. 50 ' - I %" 87 c ' ., I

" I> ~ 40 ., ;

%" 83 ll. >I

' 30 '' ' #4 67 ' ' >I

' I 'I ' #10 45 20 '' ' t i '

I ' I> I

' ' #40 27 10 ' ' I

' I

' #200 11 0 ' '

1000 100 10 1 0.1 0.01 Particle Size (mm)





Depth (ft.): Drawn By: sw Project No.: 210-187 Sample Checked By: KA Description:


Revised 04/22/2004

---



12" .. , .. 2" 1~ 314" 112~ 318" 4 8 10 16 3040 50 100 200 Sieve % Size Passin£

100

3" -I

90 ' ' 2 y, .. I -

80 2" -' I

1 y, .. 70 100 '

' ' 1" 88 ., 60 ' c u; %" 81 U> ..

D.. 50 - %" 70 c ' ., u ~ 40 ., :y, .. 61 D..

30 #4 45

20 #10 34

' ' '

I #40 21 10 I

'

I #200 10 0

1000 100 10 1 0.1 0.01 Particle Size (mm)





Fines(%) 10 PI NP 19 Depth (ft.): Drawn By: MA Project No.: 210- 187



Revised 04/; )4

~



12" 6" 3" 2" 1" 3/4" 112" 318" 4 8 10 16 3040 50 100 200 Sieve % Size Passin~

100 ' ' I 3" -I

90 2%" -

80 2" -

70 1 %" -

' 1" 100 "' 60 ' c:

' ·;;; ' %·· 90 "' ' .. I I a. 50 ' ' - I %" 90 c: ' "' ' I:! 40 "' %" 90 a. ' I

I I

' ' 30 ' ' #4 83

I

20 #10 72

' #40 47 10

#200 26 0

1000 100 10 1 0.1 0.01 Particle Size (mm)





Fines(%) 26 PI 16 24 Depth (ft.): Drawn By: MA Project No.: 210- 187


Sand, silty (SM) Figure No.: A-22

Revised 04/27/2004

Sieve Analysis Hydrometer Analysis I


12" •• , .. 2" 1" 314" 112" 318" 4 8 10 16 3040 50 100 200 Sieve % Size Passin~

100 ' ' ' 3" -'

90 2 y, .. -

80 2" -I I

' 1 %" 70 -

' '

1" -"' 60 c 'iii %" 100 "' ..

50 ' 0.. - %" 98 c ' " ' !:! 40 " %" 97 0..

30 #4 89 '

' 20 ' #10 74

' ' ' #40 30

10 I I

#200 8 0

1000 100 10 1 0.1 0.01 Particle Size (mm)

Gravel(%) I





Fines(%) 8 PI 13 25-39 ' Deoth (ft.): Drawn By: MA Project No.: 210-187



Revised 04/: J4



12" 6" 3" 2" 1" 314" 112" 318" 4 6 10 16 30 40 50 100 200 Sieve %

100 Size Passin~

3" -'

90 ' 2%" -'

' 80 I

I 2" -I I ' ! I I

1 %" 70 I I -I

' I I I

I I I 1" -

"' 60 ! ' I c ' I ·;;; I ! %" 100 "' I !

"' n. 50 I - I I %" 95 c ! .. I

~ 40 I ' .. ' %" 94 n. ' '

30 ' #4 83 !

I #10 70 20

I

#40 52 10

#200 33 0

1000 100 10 1 0.1 0.01 Particle Size (mm)




Sample SIEVE ANALYSIS Fines(%) 33 PI 10 14

Depth (ft.): Drawn By: sw Project No.: 210-187 Sample Checked By: KA

Description: Fill, sand, clayey (SC) Figure No.: A-24

Revised 04/22/2004

---



12" 6' 3" 2" 1" 314" 112" 318~ 4 8 10 16 30 40 50 100 200 Sieve % Size Passing

100 I 3" -'

90 2%" -

80 2" - I

70 1 %" 100 '

1" 93 60 I

"' I c ' "iii I %" 88

"' .. 50 0.. - ' %" 78 c .,

I! 40 ' ., %" 72 0..

'

30 #4 53

' I #10 34 20 I

'

I #40 16 10

' #200 8 ' 0

1000 100 10 1 0.1 0.01 Particle Size (mm)





Fines(%) 8 PI NP 24 Depth (ft.): Drawn By: MA Project No.: 210- 187

Sample Checked By: KA ~scrij)tion:


Revised 04/: J4

1.0 fGraph 1

0.0 ) ~

-1.0 r-..... ~ t'-.... • ...... ~

r-.. - WATER ADDED -2.0 ---I-

~ -3.0 "" ~ ....... ~ " -4.0 -8 ....... .. ...... ... ..... = " -5.0

~ " u -6.0

-7.0

-8.0

0.1 I 10 100

Applied Normal Pressure, ksf

1.0 r Gra h2

0.0 ) ~

-1.0 ........ ~ !"-... • ...... ~ -2.0 .... - WATERADDED

~----" it -3.0 ~

" ...!,.-

" -4.0 -8 "' ..

' ... = -5.0 " '\ ~

' " u -6.0

' ...... -7.0

\, -8.0

0.1 I 10 100


Graph Boring Depth Natural Dry Moisture Swell(+) I SWELL/

Density Content Consolidation(-) Soil Description CONSOLIDATION Number Number (ft)

(pel) (%) (%) GRAPH

I l TH-2 14 109 17.9 -0.2 Sand, silty (SM) Drawn By: KEA

2 TH-3 14 80 36.5 -0.5 Silt, sandy (ML) Checked By: RDJ

Job No: 210-187 Project Name: Middle Fork Compressor Station Figure A-26

YEH & ASSOCIATES INC.

1.0 I Graph 1

0.0 -....... r--1.0 - WATER ADDED

~ ""'r- -!-----•

~ -2.0

~ ~ -3.0 "' "' 8 .. -4.0 "-0 "'I ;

r-... " ~ r-... -5.0 Ill ..... 0 u -6.0

-7.0

-8.0

0.1 l lO 100


1.0 IGra h 2

0.0 -----... --1.0 ...... ---- WATER ADDED ~ • A. -2.0 ;!:., --....., ~ ........

-3.0 "' ...., >-. ' -.!.- ...... .. -4.0 0 ;

" ~ -5.0 Ill 0 u -6.0 - ---

-7.0

-8.0

0.1 I 10 100



Number Number (fl) Density Content Consolidation(-) Soil Description CONSOLIDATION

(pel) (%) (%) GRAPH

1 TH-4 4 88 29.3 -0.4 Silt, sandy (ML) Drawn By: KEA

2 TH-8 4 Ill 14.8 -0.4 Sand, clean (SP) Checked By: RDJ

Job No: 210-187 Project Name: Middle Fork Compressor Station

YEH & ASSOCIATES INC. Figure A-27

1.0 -r--~-...,......,.....,...,.......,..,...----,..-.,....-...,-.,.......,.--r-T"T-r-----.---,-.--,-Graph 1

0.0 +o.--~-t--+--+-+-+-H-1+---+---+-H-+++++---+--t-+-1--+-+-1-+l r-._t-_ -1--- WATERADDED

-1.0 r---t----t-F'!"i-~::bc=-f"=-t--t-ttttrt----t----t---ttittt1

-2.0 +---+--+-+-+-j-++++--j'--._-~;;;:::--t--f---t-++++t--+---+-+-t-+++t-1 'r--

-3.0 +----+-+-+-+-+++++---+---+-+'""'-±-r-,++H------1-+--+-+-1-+-1-t-1

-4.0 +---t--+--+-+-+-H-1+---+---+---IH-+++++--+--t-+-1--++-1-+l

-5.0 +---t--+--+-++-H-1+---+---+---IH-+++++--+--1--+-1-++-1-+l

-6.0 +----+-+-+-+-+++++---+--+-++-++++1--+----1---I--+--HH+I

-7.0 +---1---+--+-++-H-I+---+---+---IH-+++++--+--1--+-1-++-1-+l

-8.0 .L..-.....I..-l.....L-I...J....II....I..J.J.._-.....I..-L.-L-I...UI....I..J.J.._-.....I...-L.-L.....J....W--U.J

0.1 10 100


1.0 T"""---,.-....-..,.....,....,...,...,......,.--...,...--,-,......,....,...T""T",..,...---.--...,...-,..._ r-•Gra h 2

0.0 .... --.......;;:::----+-r-...-++-f-+1+++--+--+-+-++++++-------lf--+-+--+-H+H

-1.0 +----+--1""--.1-.+1'-o-+-11-+-1+------1----l-- WATER ADDED

·····-- -1--+-++-+1-1

-2.0 +-----I--+--+-+-+-+-++•~.------+--+--+-+--+--I--I-++---+--+--+-+-+-+-H-1

-3.0 +-----I--+--+-+-+-+-+++-----"1~--+-+--++-+-+++----I----+--+--++-1--H-I "", -4.0 +-----1--+--+--++-+-+++---1---f-"'"'--1- --- --- -...... ,

-5.0 +----+-+---+-+--l-+IH+--+-----1-H--l"'H-H---1--+--++--+++H

-6.0 +-----+--+---+--++-+--H+---t--t--t--f--+-I+IH---1--· --- ---(-1--1-l--l-1-1

-7.0 +---+--+--+-+-+-+-+++-----lc-----+-+--++-+-+++-----II----+-+--++-1--H-I

-8.0 ...._ _ _.____.___......J...J....I...U..L.----1----1----1-..J..J..!....I...U __ J.._.....J........J.....l-I....I...L..U

0.1 10 100


Graph Boring Number Number

Depth (ft)

I Natural~ Dry Density

(pel)

Moisture Content

(%)

Swell(+) I Consolidation(-)

(%) Soil Description

SWELL/ CONSOLIDATION

GRAPH

1

2

TH-14

TH-15

Job No: 210-187

4

4

88

89

31.3

28.7

-0.2

-0.2

,fori

YEH & ASSlll:IA1'ES. INI

Fill, sand, clayey (SC)


·Station

By:

By:

KEA

RDJ

Figure A-28

1.0 I Graph 1

0.0

~ r-.... -1.0 ~ ~""-- r-.. • I--A 1'-t. -2.0

~ -3.0 "'

1--l--- WATERADDED

8 = -4.0 ;§ "

....... ~ -5.0 0

l!l 0 u -6.0

-7.0

-8.0 0.1 10 100

1.0

0.0

-1.0 ~ •

~ -2.0

il: -3.0 "' 8 = -4.0 ,g " ~ -5.0 0

l!l 0 u -6.0

-7.0

-8.0

Graph Boring Number Number

1 TH-15

2 TH-16

Job No: 210-187


I I I I I II --- WATERADDED

fGra h 2

+---1----+-+-++-+-+++---1-·· -·-- -1-+-+-+++---+---+---1--+-++++-1

+---1---1-- ---- - - - ---··-----1--1-+-H-++-l-l-----t--t-+-t-1--I--IH-1

0.1

Depth

(ft)

14

4

Natural Dry Density

(pet)

98

89

Moisture Content

(%)

24.5

29.0

10


Swell(+) I Consolidation(-) Soil Description

(%)

-0.5 Sand, clayey (SC)

-0.3 Silt, sandy (ML)

Project Name: Middle Fork Compressor Station

YEH & ASSOCIATES, INC.

100

SWELL/ CONSOLIDATION

GRAPH

Drawn By: KEA

Checked By: RDJ

FigureA-29

1.0 I Graph 1

0.0 --r--- 1---- WATER ADDED -1.0 -- -~

'-.... • ,.::,

-2.0 ;!:., 1'--~ ~ "' -3.0 ...... 8 .....

~'I'-= -4.0 ~ " ~ -5.0 ~ 0 u -6.0

-7.0

-8.0

0.1 1 10 100


1.0 I Gra h2

0.0

............... ...... -1.0 t"-... ~ ...... • .....

i -2.0 - WATER ADDED ---3.0 r--"' I"-. ;:...

"'-., ..!.-= -4.0 - ~

~- -· ·- .. ------·--·------ . -0 ;

" ~ -5.0 ~ 0 u -6.0 --~ ··--· --- . - ·- - ----

-7.0

-8.0

0.1 1 10 100




(pel) (%) (%) GRAPH

l TH-16 9 95 19.9 ·0.3 Silt, sandy (ML) Drawn By: KEA

2 TH-18 4 102 22.0 ·0.2 Fill, sand, silty (SM) Checked By: RDJ

Job No: 210-187 Project Name: Middle Fork Compressor Station FigureA-30


1.0 I Graph 1

0.0

~ -1.0 ~ ~ ~ -2.0

" ... ' ~

~ -3.0

I'-I'- -f.---~ WATER ADDED

" ~ .g -4.0 .. '-..... ~ -5.0 "' !'....... " <> u -6.0 ....,

..... I' -7.0

-8.0

0.1 I 10 100


1.0 I Gra h2

0.0

-1.0 ~

~ -2.0

... ~ -3.0 I!' 8 " -4.0 .g ..

~~- ---

"' "' -5.0 <> "' " 0 u -6.0 ~ - - ---- -

-7.0

-8.0

0.1 I 10 100




(pel) (%) (%) GRAPH

1 TH-19 4 92 25.8 -0.4 Fill, sand, clayey (SC) Drawn By: KEA

2 Checked By: RDJ

Job No: 210-187 Project Name: Middle Fork Compressor Station Figure A-31


·~ YEH & ASS\J~IATES, INC

Project No· 210-187

Sample Location Moisture

Dry Density Test Sample Content Hole

Depth (It) Type (%)

TH-2 14 CA 17.9

15 ss 27.1

TH-3 4 CA 9.8

14 CA 36.5

25-25.5 Bulk 49.0

TH-4 4 CA 29.3

TH-<3 14 CA 8.3

24 ss 17.3

TH-7 15-19 Bulk 20.2

TH-8 4 CA 14.8

6-9 Bulk 25.4

15-19 Bulk 27.4

29 ss 18.0

TH-9 4 CA 21.9

TH-11 10-14 Bulk 22.4

TH-12 9 CA 12.4

CA- Modified California sampler SS - Standard split spoon sampler NL - Indicates non-liquid NP - Indicates non-plastic

(pc1)

109

112

80

88

119

111

86

Summary of Laboratory Test Results


Grain Size Analysis Atterberg Umits Water Gravel Fines Soluble

Swell(+)/

>#4 Sand <#200 LL PL PI Sulfate

Consolidation(-)

(%) (%)

(%) (%) at 1,000 psf (%)

-0.2

20 53 27 34 24 10

31 43 26 37 22 15 0.028

NL NP NP -0.5

1 34 65 46 28 18

-0.4

NL NP NP

48 43 9 NL NP NP

21 62 17 33 22 11

-0.4

17 62 21 35 24 11

16 54 30 37 23 14

47 44 9 NL NP NP

NL NP NP

18 69 13 35 23 12

38 52 10 NL NP NP [._ ___ --------

Page 1 of3

Unconf. Camp.

Strength Soil Description

(psf)

Sand, silty (SM)

Sand, silty (SM)

Sand, clayey (SC)

Silt, sandy (ML)

Silt, sandy (ML)

Silt, sandy (ML)

Sand, clean (SP)

Gravel, slightly silty (GP-GM)

Sand, clayey (SC)

Sand, clean (SP)

Sand, clayey (SC)

Sand, clayey (SC)

Gravel, slightly silty (GW-GM)

990 Fill, silt sandy (M L)

Sand, clayey (SC)

Fill, sand, silty (SM)

·~ YEH & ASSOCIATES, INC



Dry Densi~ Test Sample Content Hole

Depth (ft Type (%)

TH-13 9 CA 29.0

15.5-18. Bulk 23.9

TH-14 4 CA 31.3

9 ss 13.9

19 CA 18.6

TH-15 2 CA 20.7

4 CA 28.7

14 CA 24.5

24 Bulk 30.5

37.5-39 Bulk 17.8

TH-16 4 CA 29.0

9 CA 19.9

14 CA 41.8

24 CA 11.8

TH-17 4 CA 12.8

TH-18 4 CA 22.0

14 CA 18.3

CA - Modified California sampler SS - '>tandard split spoon sampler NL dicates non-liquid NP- Indicates non-plastic

(pet)

84

88

101

89

98

89

95

113

102

98



Grain Size Analysis Atterberg Limits Water Gravel Fines Soluble

Swell(+)/ Sand Consolida~on (-)

>#4 (%)

<#20( LL PL PI Sulfate at 1,000 psi (%

(%) (%) (%)

1 38 61 43 25 18

13 70 17 35 23 12

-0.2

29 56 15 40 17 23

56 34 10 35 21 14

54 36 19 17

-0.2

-0.5

28 45 27 36 23 13

7 48 45 34 18 16

-0.3

-0.3

46 26 20

56 34 10 NL NP NP

28 51 21 NL NP NP 0.014

-0.2

33 56 11 NL NP NP

PagE:-z of3

-·---

Unconf. Comp.

Soil Description Strength (ps~

750 Clay, sandy (CL)

Sand, clayey (SC)



Gravel, clayey (GC)

Fill, clay (CL)


Sand, clayey (SC)

Sand, clayey (SC)

Sandstone Bedrock

Silt, sandy (ML)

Silt, sandy (ML)

Sand, clayey (SC)

Gravel, slightly silty (GP-GM)

Fill, sand, silty (SM)

Fill, sand, silty (SM) ' I

Sand, s6ghtly silty (SW-SM) I

I

·~ YEH & ASSbCIATES, INC



Dry Densi~ Test Sample Content Hole

Depth (It Type (%)

TH-18 15-17.5 Bulk 18.4

19 CA 14.7

24 ss 23.7

25-39 Bulk 30.4

TH-19 4 CA 25.8

14 CA 19.3

24 ss 21.4

CA - Modified California sampler SS - Standard split spoon sampler NL - Indicates non-liquid NP - Indicates non-plastic

(pc~

92



Grain Size Analysis Atterberg Umits Water Gravel Fines Soluble

Swell(+) I Sand Consolidation(-)

>#4 (%)

<#20( LL PL PI Sulfate at 1,000 psf (% (%) (%) (%)

25 65 10 33 22 11

55 35 10 NL NP NP

17 57 26 43 27 16

11 81 8 38 25 13

-0.4

17 50 33 33 23 10

47 45 8 NL NP NP

Page 3 of3

Unconf. Comp.

Soil Description Strength (ps~

Sand, slightly silty (SW-SM)

Gravel, slightly silty (GW.GM)

Sand, silty (SM)

Sand, slighty silty (SW-SM)


Sand, clayey (SC)

Gravel, slightly silty (GW-GM)

I(+A Kumar & Associates, Inc. Geotechnical and Malenals Engineers and Environmental Scientists

November 26, 2008

Raymond Williams HOAD Industrial Services 13025 WCR 16 Fort Lupton, Colorado 80621

---ACEC MEMBER

2390 South Lipan Street Denver, CO 80223

phone: (303) 742-9700 fax: (303) 742-9666

e~mail: [email protected] www.kumarusa.com

Other Office Locations: Colorado Springs, Fort Collins, Pueblo and Winter Park/Fraser, Colorado

Subject: Geotechnical Engineering Study, Proposed Water Treatment Facility, Encana Middle Fork Compressor Station, County Road 215, Garfield County (North of Parachute), Colorado

Project No. 08-1-511

Dear Mr. Williams:

This letter presents the results of a geotechnical engineering study performed for the proposed water treatment facility to be constructed at Encana Oil & Gas (USA), Inc.'s Middle Fork Compressor Station located on County Road 215 in Garfield County, Colorado, approximately 15 miles north of the Town of Parachute. The project site is shown on Fig. 1. The study was conducted for the purpose of developing geotechnical engineering recommendations for the design and construction of the treatment facility foundations and floor slabs. The study was conducted in general accordance with the scope of work in our Proposal No. P-08-600 to HOAD Industrial Services, dated October 1 0, 2008.

Kumar & Associates previously performed the geotechnical study for the existing compressor station. The results of that study were provided under our Project No. 05-1-203 in a report dated April 25, 2005. Data from the borings and other information developed for that study were used in preparation of this report.

Planned Construction: We understand that the proposed treatment facility will consist of two buildings to be located west of an existing lined water storage pond. The larger of the buildings will have a footprint area of about 11,700 square feet, with dimensions of 130 feet in the north-south direction and 90 feet in the east-west direction. The smaller building will be located 25 feet south of the larger building and will have a footprint area of about 2,900 square feet, with dimensions of 32 feet in the north-south direction and 90 feet in the east-west direction. The buildings will house skidded water treatment equipment and tanks.

Both buildings will be at-grade structures with no below-ground structures. Both buildings will generally be single-level structures, although one bay of the larger building will have a structural steel mezzanine supporting a filter press and a dissolved gas flotation unit. We assume the buildings will be pre-engineered metal structures with light to moderate column loads. We understand that the equipment will not include large pumps or compressors, and that dynamic loads due to machinery operation will not be significant.

HOAD Industrial Services November 26, 2008 Page2

If the proposed construction varies significantly from that described above or depicted in this report, we should be notified to reevaluate the recommendations provided in this report.

Site Conditions: At the time of our field exploration program, the site was a storage/staging area for the compressor facility and was occupied by work trailers, construction materials, and miscellaneous equipment and other items. The site was bounded on the east by the existing water storage pond, on the north by graded and ungraded areas of the compressor facility, on the south by unpaved roadways and a branch of Parachute Creek, and on the west by a branch of Parachute Creek. The site had been graded to a relatively flat and level configuration, and was free of vegetation.

Subsurface Conditions: The subsurface conditions at the general location of the water treatment facility were explored by drilling three (3) exploratory borings to depths of about 30 feet at the approximate locations shown on Fig. 1. The logs of the exploratory borings are presented on Fig. 2, and a legend and associated explanatory notes are presented on Fig. 3.

Laboratory testing was performed on selected soil samples obtained from the borings to determine soil moisture content, dry density, gradation, Atterberg limits, and concentration of water soluble sulfates. The results of the laboratory tests are shown to the right of the logs on Fig. 2 and summarized in Table I.

Subsurface conditions encountered at the boring locations consisted of about 3 to 8 feet of fill overlying natural alluvial soils extending to the full depths explored. The fill generally consisted of moist, brown and gray, clayey sand with gravel to clayey gravel with sand. The fill contained scattered cobble-sized shale fragments and isolated metal and inorganic debris. Although the lateral extent, depth and degree of compaction of the existing fill were not determined as part of this study, the condition of the existing fill appeared to be highly variable, suggesting that the fill may not have been placed under controlled conditions.

The alluvial soils underlying the fill consisted primarily of interbedded lean clay with sand and clayey sand with gravel, with isolated zones of sandy silt and silty clayey sand with gravel and occasional lenses of sand and shale fragments. The alluvial soils were slightly moist to moist, becoming wet below the water table, and ranged from brown to dark brown and gray to dark gray. Based on sampler penetration resistance blow counts, the clay generally ranged from soft to stiff to very stiff to hard around 30 feet in Borings 1 and 3, and the sand generally from loose to medium dense to dense around 30 feet in Boring 1.

Ground water was encountered during drilling at depths ranging from about 14 to 17 feet below existing ground surface. Ground water was measured at a depth of about 16 feet in Boring 2 about 3 hours after completion of drilling. Although these ground water conditions may not represent stabilized ground water levels at the time, the current and previous ground water data suggest that site ground water levels may generally be about 15 feet below existing site grades. Seasonal ground water levels may vary and may be affected by water level changes in the nearby Parachute Creek.

Geotechnical Engineering Considerations: Site conditions expected to impact building and floor slab performance include the existing non-engineered fills and near-surface zones of relatively soft or loose natural alluvial soils. The existing, predominantly ·

_, Kumar & Associates, Inc.

HOAD Industrial Services November 26, 2008 Page 3

granular fills are considered to be unsuitable in their current condition for support of building foundations or floor slabs, as are near-surface soft/loose natural soils. However, based on the anticipated light to moderate structural loads, it should be feasible to support the buildings on shallow spread footing or mat foundations provided the foundations are underlain by at least five feet of compacted, predominantly granular structural fill extending to undisturbed natural soils. This may require removal and replacement of existing fills to depths of more than five feet below footings and mats.

Slab-on-grade floors present a problem where existing non-engineered fill is present beneath the floor slab, particularly when the existing fill may contain debris or other deleterious material that may lead to fill settlement. The most positive method for limiting slab movements caused by settlement of existing fill is to completely excavate and replace the existing fill with properly compacted, predominantly granular structural fill similar to that discussed above for footings and mats. A cost-saving alternative is to remove a portion of the existing fill beneath lightly-loaded slabs, provided that the risk of some slab movement is acceptable to the owner.

The existing fills should be suitable for reuse as compacted structural fill provided they do not contain deleterious materials, including trash, organic materials, or excessive amounts of inorganic debris.

Shallow Spread Footing and Mat Foundations: The design and construction criteria presented below should be observed for a spread footing or mat foundation system. The construction details should be considered when preparing project documents.

1. Footings and mats established directly on a minimum of 5 feet of properly compacted, predominantly granular structural fill extending to undisturbed natural soils should be designed for an allowable soil bearing pressure of 2,500 psf. Allowable bearing pressures may be increased by 1/3 for transient load conditions.

2. Spread footings should have a minimum footing width of 16 inches for continuous footings and 20 inches for isolated pads.

3. Based on experience, we estimate total settlement for footings and rigid mats designed and constructed as discussed in this section will be 1 inch or less. Differential settlements between adjacent foundation elements or across a mat are estimated to be approximately Y, to % of the total settlement. Settlement of the foundation soils was calculated based on elastic theory. Non-uniformity of the subsurface conditions will contribute to total and differential settlements. Settlements should be substantially complete shortly after construction is finished.

0&-1·5111lr

Settlements of mats under static load were computed assuming a rigid mat and a uniformly distributed working contact pressure of 1,000 psf, which is significantly less than the allowable contact pressure. Note that deviation from the rigid assumption will also contribute to total and differential settlements.

Rigidity of a mat is dependent on the mat dimensions, load distribution, and the modulus of subgrade reaction of the supporting soils. We recommend mat foundations be analyzed to determine if the rigidity assumption is valid. If a mat cannot be considered rigid, the soil pressure distribution should be computed ·

Kumar & Associates, Inc.

"

HOAO Industrial Services November 26, 2008 Page4

using a method which models the soil-structure interaction, such as the beam on an elastic foundation procedure. For that case, a modulus of vertical subgrade reaction equal to 200 tcf may be used for the supporting granular fills. The modulus value given is for a 1-foot square plate and must be corrected for mat shape and size.

When the mat contact pressure distribution has been determined, we should be contacted to reanalyze the settlement pattern of the mat. The process of evaluating soil pressure distribution beneath the mat may require several iterations for a foundation which classifies between rigid and flexible.

4. Exterior foundations and foundations beneath unheated areas should be provided with adequate soil cover above their bearing elevation for frost protection. Placement of foundations at least 36 inches below the exterior grade is typically used in the site vicinity.

5. The lateral resistance of a spread footing or mat placed on properly compacted, predominantly granular structural fill material will be a combination of the sliding resistance of the footing on the foundation materials and passive earth pressure against the side of the footing. Resistance to sliding at the bottoms of the footings can be calculated based on an allowable coefficient of friction of 0.35. Passive pressure against the sides of the footings can be calculated using an equivalent fluid pressure of 200 pcf. The above values are working values.

6. Granular foundation soils should be densified with a smooth vibratory compactor prior to placement of concrete.

7. Areas of very soft or excessively loose natural soils encountered at the base of the excavations for the foundation fill should be removed and replaced with compacted structural fill. If soft or excessively loose subgrade conditions prevent achieving the recommended compaction, the fill subgrade may need to be stiffened using a coarse stabilizing material worked into the fill subgrade.

8. Structural fill should meet the requirements for structural fill described in the "Floor Slabs" section of this report. Structural fill beneath footings and mats should be placed in maximum 8-inch thick lifts and compacted to at least 98% of the standard Proctor (ASTM 0698) maximum dry density at a moisture content within 2 percentage points of optimum. Foundation excavations should extend to a lateral distance outside the footing equal to the depth of required overexcavation.

9. Structural fill placed against the sides of the footings or mats to resist lateral loads may consist of on-site or imported granular materials compacted to at least 95% of the standard Proctor (ASTM 0698) maximum dry density at a moisture content within 2 percentage points of optimum.

10. A representative of the project geotechnical engineer should observe all foundation excavations and backfilling activities prior to concrete placement.



Floor Slabs: The following measures should be taken to reduce the risk of settlementrelated damage to slabs-on-grade floors.

1. Preferably, all existing fills should be completely removed and replaced with a minimum of 3 feet of properly compacted structural fill extending to undisturbed natural soils. As previously discussed, an alternative would be to remove existing fill to a depth of at least 3 feet below slab subgrade and backfill the subexcavation with properly compacted structural fill. Prior to placing structural fill, the geotechnical engineer should observe the material exposed in the excavation, and the fill excavation should be deepened if the risk of settlement is not acceptable to the Owner based on discussion with the geotechnical engineer regarding conditions observed in the excavation.

2. Structural fill beneath at-grade slabs may consist of on-site fills and natural soils free of organics and deleterious material. If necessary, imported fill materials should have a plasticity index of 15 or less and less than 50% passing the No. 200 sieve, and also be free of organics and deleterious material.

Structural fill beneath slabs should be compacted to at least 95% of the standard Proctor (ASTM 0698) maximum dry density at a moisture content within 2 percentage points of optimum. In fill areas where the subgrade soils consist of existing granular fills left in place, the subgrade soils should be scarified to a depth of 8 inches, adjusted to a moisture content near optimum, and recompacted to provide a firm, uniform base for subsequent fill placement.

3. To reduce the effects of differential movements, floor slabs should be separated from all bearing walls and columns with expansion joints that allow unrestrained vertical movement.

4. Floor-slab control joints should be used to reduce damage due to shrinkage cracking. The joint spacing and slab reinforcement should be established by the designer based on experience and the intended slab use.

5. If moisture-sensitive floor coverings or equipment will be used, mitigation of moisture penetration into the slabs, such as by use of a vapor barrier, may be required. If an impervious vapor barrier membrane is used, special precautions will be required to prevent differential curing problems which could cause the slabs to warp. This topic is addressed by ACI 302.1 R.

6. The geotechnical engineer should evaluate the suitability of proposed underslab fill material.

Surface Drainage: Proper surface drainage is important for acceptable performance of proposed structures during construction and after the construction has been completed. Drainage recommendations provided by local, state and national entities should be followed based on the intended use of the structures. The following recommendations should be used as guidelines and changes should be made only after consultation with the geotechnical engineer.

1. Excessive wetting or drying of the foundation subgrade should be avoided during construction.

0 1·51 II



2. Exterior backfill should be adjusted to near optimum moisture content and compacted to at least 95% of the standard Proctor (ASTM D 698) maximum dry density.

3. The ground surface surrounding the exterior of the structures should be sloped to drain away from the foundation in all directions. We recommend a minimum slope of 6 inches in the first 1 0 feet. Site drainage beyond the 1 0-foot zone should be designed to promote runoff and reduce infiltration. The slope may be changed as required for handicap access points in accordance with the Americans with Disabilities Act.

4. Pending of water should not be allowed in backfill material in a zone within 10 feet of the foundation walls, whichever is greater.

5. Roof downspouts and drains should discharge well beyond the limits of all backfill.

6. Excessive landscape irrigation should be avoided within 10 feet of the foundation walls.

Seismicitv: The site is located on an area of low seismic activity. Based on fault maps prepared by the Colorado Geological Survey, the closest mapped faults to the site are located more than 40 miles to the east and more than 45 miles to the west-southwest. Historic earthquake data for western Colorado indicate recorded moment magnitudes of less than 4.4, and the Colorado Geophysical Survey estimates a maximum moment magnitude of 5 for potentially active nearby faults.

Based on data from the exploratory borings, the site soil profile to a depth of 100 feet is anticipated to consist of between 30 to 35 feet of cohesive and granular overburden soils underlain by very hard shale bedrock. The overburden soils classify as IBC Site Class D, and, based on our experience, the bedrock anticipated to underlie the site would classify as IBC Site Class A or B, or possibly C. The IBC limits the use of Site Classes A and B to profiles where the overburden thickness between the base of the foundations and the rock surface is 10 feet or less. Based on an overburden thickness of more than 30 feet, including several feet of relatively soft and loose soils, and on our experience at sites with similar subsurface conditions, we recommend a design soil profile for the site of IBC Site Class D.

Although relatively soft and loose conditions were encountered, and ground water is relatively shallow, site seismicity is relatively low. Based on the results of a limited liquefaction analysis based primarily in sampler penetration resistance blow counts, liquefaction should not be a design consideration.

Temporarv Excavations: We assume that the excavations for the project will be constructed by excavating the side slopes to a stable configuration. The existing fills and natural alluvial soils typically classify as Type C materials in accordance with OSHA requirements. All excavation should be performed in accordance with local, State and OSHA requirements. The presence of ground water in excavated slopes may require slopes flatter than those recommended by OSHA and/or require temporary shoring. The natural granular alluvial soils are likely to ravel and flow if encountered below ground water. If unstable soil conditions are encountered, the geotechnical engineer should be



notified so that additional recommendations can be provided, if necessary, including recommendations for dewatering.

Design and Construction Suooort Services: Kumar & Associates, Inc. should be retained to review the project plans and specifications for conformance with the recommendations provided in our report. We are also available to assist the design team in preparing specifications for geotechnical aspects of the project, and performing additional studies if necessary to accommodate possible changes in the proposed construction.

We recommend that Kumar & Associates, Inc. be retained to provide observation and testing services to document that the intent of this report and the requirements of the plans and specifications are being followed during construction, and to identify possible variations in subsurface conditions from those encountered in this study so that we can re-evaluate our recommendations, if needed.

Limitations: This study has been conducted in accordance with generally accepted geotechnical engineering practices in this area for exclusive use by the client for design purposes. The conclusions and recommendations submitted in this report are based upon the data obtained from the exploratory borings at the locations indicated on Fig. 1, observed site conditions, and the proposed type of construction. This report may not reflect subsurface variations that occur between the exploratory borings and extent of variations across the site may not become evident until site grading and excavations are performed. If during construction, fill, soil, rock or water conditions appear to be different from those described herein, Kumar & Associates, Inc. should be advised at once so that a re-evaluation of the recommendations presented in this report can be made. Kumar & Associates, Inc. is not responsible for liability associated with interpretation of subsurface data by others.

If you have any questions, or if we can be of further assistance, please contact us.

Sincerely,

KUMAR & ASSOCIATES, INC.

Wade Gilbert, P.E.

JWG/mj Rev. by: AFC Enclosures cc: file, book

013-1-511 Hr


:; . 0

i ~ <' :;

E' ·-~J, ~~ I~

,__ __ _ 100 0 100 200

APPROXIMATE SCALE-FEET

'~-;. -~-' it'"' ... -~,- ~-

APPROXIMATE 10.3 MILES TO PARACHUTE COLORADO

''IF"''

. ;;·

.,

-~-

" ' -~~~~;;~:--.'~

.. , ~"

... 1.,

!<\~ .. -,,

1 ;,: f

~,.~I

(y I •• '·~ iiiJi" .. _I

•

'/1----------------.-------------------------r------------------------------------------------r---------~ ~~

08-1-511 Kumar & Associates LOCATIONS OF EXPLORATORY BORINGS Fig. ~! ij.'(.-z>L---------------~------------------------L------------------------------------------------L--------_J

. ~ ol 0

' ~

~ -;; ~

~ ~

g_l ~~ :!~ ,g

0

5

10

f-w w "-I 15 :I:

f-0.. w 0

20

25

30

BORING BORING 2

7/12 WC=18.7 00=1 07.2 +4=24 -200=32 19/12 LL=30 WC=5.6 Pl=8 +4=46

-200=16

5/12 7/12 WC=16.6 00=91.9 -200=44 LL=33 Pl=8 WS<0.02

10/12 10/12 WC=11.6 +4=22 -200=26 WSS<0.02

3/12 6/12 WC=24.2 +4=30 -200=16

5/12 12/12 WC=36.2 WC=20.9 00=84.8 +4=39 +4=4 -200=11 -200=83 LL=44 Pl=17

7/15 2/12

BORING 3

48/12

6/12 WC=29.9 00=82.0

3/12 WC=34.4 -200=52 LL=30 Pl=3

' :3/12 I I I I I I I I I I

' 5/12

20/12 WC=37.3

0

5

10

15

20

25

34/12 WC=20.9 OD=1 02.1

15/12 DD=82.2 30

WC=33.5 +4=24 -200=40 LL=33 PI=?

* GROUND WATER LEVEL MEASURED 3 HOURS AFTER DRILLING WAS COMPLETED.

f-w w "-I

:I: f-0.. w 0

~~~-------------~-------------------T--------------------------------------~--------4 o-t;

Kumar & Associates ~i 08-1-511 LOGS OF EXPLORATORY BORINGS Fig. 2 ~~~----------~--------------------~--------------------------------------~------~

~r ~~ -. •8

LEGEND

~FILL: CLAYEY SAND WITH GRAVEL (SC) TO CLAYEY GRAVEL WITH SAND (GC), FINE TO COARSE GRAINED, MOIST, MOTTLED BROWN AND GRAY, SCATTERED GRAVEL AND COBBLE-SIZED SHALE FRAGMENTS, ISOLATED METAL AND INORGANIC DEBRIS.

[d INTERBEDDED LEAN CLAY WITH SAND (CL) AND CLAYEY SAND WITH GRAVEL (SC), ISOLATED ZONES OF SANDY SILT (ML) AND SILTY CLAYEY SAND WITH GRAVEL (SC-SM), OCCASIONAL LENSES OF SAND AND SHALE FRAGMENTS, VERY LOOSE TO MEDIUM DENSE, SLIGHTLY MOIST TO MOIST TO WET BELOW GROUND WATER, BROWN TO DARK BROWN AND GRAY TO DARK GRAY.

p DRIVE SAMPLE, 2-INCH I.D. CALIFORNIA LINER SAMPLE.

13/12 DRIVE SAMPLE BLOW COUNT. INDICATES THAT 13 BLOWS OF A 140-POUND HAMMER FALLING 30 INCHES WERE REQUIRED TO DRIVE THE SAMPLER 12 INCHES.

t~~ DISTURBED BULK SAMPLE.

--:9:-- DEPTH TO WATER LEVEL ENCOUNTERED AT THE TIME OF DRILLING.

NOTES

1. THE EXPLORATORY BORINGS WERE DRILLED ON NOVEMBER 7, 2008 WITH A 7-INCH DIAMETER CONTINUOUS FLIGHT HOLLOW STEM POWER AUGER.

2. THE LOCATIONS OF THE EXPLORATORY BORINGS WERE MEASURED APPROXIMATELY BY PACING FROM FEATURES SHOWN ON THE SITE PLAN PROVIDED.

3. THE ELEVATIONS OF THE EXPLORATORY BORINGS WERE NOT MEASURED AND THE LOGS OF THE EXPLORATORY BORINGS ARE PLOTTED TO DEPTH.

4. THE EXPLORATORY BORING LOCATIONS SHOULD BE CONSIDERED ACCURATE ONLY TO THE DEGREE IMPLIED BY THE METHOD USED.

5. THE LINES BETWEEN MATERIALS SHOWN ON THE EXPLORATORY BORING LOGS REPRESENT THE APPROXIMATE BOUNDARIES BETWEEN MATERIAL TYPES AND THE TRANSITIONS MAY BE GRADUAL.

6. GROUND WATER LEVELS SHOWN ON THE LOGS WERE MEASURED AT THE TIME AND UNDER CONDITIONS INDICATED. FLUCTUATIONS IN THE WATER LEVEL MAY OCCUR WITH TIME.

7. LABORATORY TEST RESULTS: WC = WATER CONTENT (%) (ASTM D 2216); DD = DRY DENSITY (pel) (ASTM D 2216); +4 = PERCENTAGE RETAINED ON NO. 4 SIEVE (ASTM D 422); -200 = PERCENTAGE PASSING NO. 200 SIEVE (ASTM D 1140); LL = LIQUID LIMIT (ASTM D 4318); PI = PLASTICITY INDEX (ASTM D 4318); WSS = WATER SOLUBLE SULFATES (%) (AASHTO T 290).

~~r-----------,-------------------,-------------------------------------,-------4 o, Kumar & Associates LEGEND AND NOTES Fig. 3 ~t 08-1-511

~~ ~------~--------------~--------------------------~----~

0 • " .. 0

' -0

-" ' Q

/ 0

' ' "

' ..

~

:."1 ~

1

--' --' w ;;:: V1 0

I -....... ......_ ......

z ..... 0 -1 i= <( Cl :::i 0 V1 -2 z 0 u

-3

-4

.I

0

-------......._

~ r--.. :."1

" ~

-1

--' --' w ;;::

-2 V1

I

z 0 -3 i= <( Cl :::i 0 V1 -4 z 0 u

-5

-6 These teol r .. ul\.1 apr,'y only to lhe oomrl•• luted, The ulttlg report ohol not be reprod~ed, ucept kl full, ~ilhoul U.e wrillen opprovol of Kumar and Anoclolu, Inc. Swell

;:i:~~~~:n.M,'~"t.."~;:. 1n

.1

08-1-511 Kumar & Associates

SAMPLE OF: Fill: Clayey Sand with Gravel (SC)

FROM: Boring 1 @ 1 '

we = 18.7%, DO = 107.2 pcf

-200 = 32%, LL = 30, PI = B

ADDITIONAL COMPRESSION UNDER CONSTANT PRESSURE

_...f-' DUE TO WETTING

v·Y v /

........

-~

1.0 APPLIED PRESSURE - KSF 10 100

SAMPLE OF: Fill: Clayey Sand with Gravel (SC)

FROM: Boring 2 @ 4'

we = 16.6%, DO = 91.9 pcf

-200 = 44%, LL = 33, PI = B

~ EXPANSION UNDER CONSTANT

\ PRESSURE UPON WETTING

'\ \ \

1.0 APPLIED PRESSURE - KSF 10 100

SWELL -CONSOLIDATION TEST RESULTS Fig. 4

TABLE I SUMMARY OF LABORATORY TEST RESULTS

PROJECT NO.: PROJECT NAME: DATE SAMPLED: DATE RECEIVED:

08-1-511 HOAD, Encana Parachute 11-7-08 11-17-08

SAMPLE LOCATION -- NATURAL NATURAL

DEPTH DATE MOISTURE DRY

BORING TESTED CONTENT DENSITY (feet) (%) (pcf)

1 1 11-18-08 18.7 107.2

1 9 11-18-08 11.6

1 19 11-18-08 36.2 64.8

1 29 11-18-08 20.9 102.1

2 1 11-18-08 5.6

2 4 11-18-08 16.6 91.9

2 14 11-18-08 24.2

2 19 11-18-08 20.9

3 4 11-18-08 29.9 82.0

3 9 11-18-08 34.4

3 14-19 11-18.{)8 33.5

3 29 11-18-08 37.3 82.2

GRADATION PERCENT ATIERBERG LIMITS

GRAVEL SAND PASSING LIQUID PlASTICITY NO. 200 L~IT IN~~ (%) (%) SIEVE Yo) rio

24 44 32 30 8

22 52 26

4 13 83 44 17

46 38 16

44 33 8

30 54 16

39 50 11

52 30 3

24 36 40 33 7

WATER SOLUBLE SOIL OR BEDROCK TYPE SULFATES

(%)

Fill: Clayey Sand wlth GraveiJSC)

<0.02 Clayey Sand with Gravel . (SC)

Lean Clay with Sand (CL)

Clayey Sand with Gravel (SC)

Fill: Clayey Gravel with Sand (GC)

<0.02 Fill: Clayey Sand with GraveljSC)

Clayey Sand with Gravel (SQ)_

Clayey Sand with Gravel (SQ)_

Clayey Sand wtlh Gravel (SC)

Sandy Sift (ML)

Silty Clayey Sand wtth Grave!l.SM-Sc)_

Lean Clay with Sand (CL) --

january 24, 2011 project no. 210-187 encana oil gas (usa ... · ) january 24, 2011 project no....

Documents