GEOTECHNICAL ENGINEERING REPORT PROPOSED GABION BASKET RETENTION WALLS & RIP/RAP BIG FOSSIL CREEK @ GLENVIEW AND BROADWAY ROADS

HALTOM CITY, TEXAS

Prepared for: CITY OF HALTOM CITY

EWL Report No. HC081718 May 2008

eotechnical Studies Group, Inc. ~ Ellerbee Walczak Lawrence May 28,2008 A DMsion of BIert>ee/Walczak. Inc.

City of Haltom City PO Box 14246 Haltom City, Texas 76117

Attn Mr. Lenny Williams

Re Geotechnical Engineering Report Proposed Gabion Basket Retention Wall & Rip-Rap Bid Fossil Creek at Glenview and Broadway Roads Haltom City, Texas EWL Report No. HC081718

Gentlemen:

Ellerbee-Walczak-Lawrence, Inc. (EWL), a division of EWI, has completed its Preliminary Geotechnical Engineering Report at the above referenced location. The results are presented in the attached report

Please do not hesitate to contact us if you have any questions regarding the information in this report or if we can be of any additional assistance

It has been a pleasure providing geotechnical services for this project.

c-4 c ­I v

Brent Doug s, Principal i........-.

Copies Submitted (3)

4501 Broadway Ave. • P.O. Box 14809 • Haltom City. Texas 76117 Office 817-759-9999 • Fax 817-759-1888

TABLE OF CONTENTS

Page

1.0 SITE AND PROJECT INFORMATION 1

2.0 SCOPE OF SERViCES 1

3.0 FIELD OPERATIOI\JS 1

4.0 LABORATORY TESTING 2

5.0 SITE SUBSURFACE CONDITIONS 2

6.0 GROUNDWATER 3

7.0 ANALYSIS AND RECOMMENDATIONS 3 7.1 Foundation System 3

7.1.1 Straight Drilled Shafts 3 7.1.2 Lateral Capacity 4 7.1.3 Soil Induced Uplift Loads 4 7.1.4 Drilled Shaft Construction Considerations 4

7.2 Gabion Basket Walls 5 7.3 Earthwork/Site Grading 6 7.4 Global Slope Stability 7 7.5 Permanent Slopes 8

8.0 LIMITATIONS 8

APPENDIX A Figure

Plan of Borings 1 Boring Logs 2 - 4 Key to Symbols used on Boring Logs 5

APPENDIX B Figure

Slope Stability Analysis 1 - 6

GEOTECHNICAL ENGINEERING REPORT PROPOSED GABION BASKET RETENTION WALLS & RIP/RAP BIG FOSSIL CREEK @ GLENVIEW AND BROADWAY ROADS

HALTOM CITY, TEXAS

1.0 SITE & PROJECT INFORMATION

The project sites are located near the Broadway and Glenview bridges crossing Big Fossil creek

in the City of Haltom City, Tarrant County, Texas. The creek bank near Glenview was heavily

forested with the exception of the utility easement. The Broadway location was generally more open and contained trees near the creek banks. We understand significant creek erosion has

occurred in the past.

Planned construction consists of a gabion basket wall for major erosion protection and slope

improvements with rip/rap in the less eroded areas. The slopes will extend to heights of

approximately 17 feet, or less at the Broadway location and approximately 15 feet, or less, at the Glenview location.

2.0 SCOPE OF SERVICES

The purpose of our geotechnical services for this site were to:

• Evaluate the subsurface conditions encountered in the borings.

• Evaluate the pertinent engineering properties of the recovered samples.

• Provide recommendations for gabion basket wall foundations, earthwork and site grading.

• Global slope stability studies on three cross-sections.

3.0 FIELD OPERATIONS

The subsurface conditions of the site were evaluated by performing three borings which were

drilled on April 25, 2008 at accessible open locations clear of utilities. The approximate boring

locations are provided on the Site Plan (Figure 1) in the Appendix. The results of the field

exploration program are presented on the Logs of Boring (Figures 2 through 4) in the Appendix. A key to symbols used on the boring logs is presented on Figure 5.

A truck-mounted drilling rig with continuous flight augers was used to advance the borings. Soils were sampled using steel tubes and during performance of standard penetration tests. The samples were extruded in the field, logged, sealed, and packaged to preserve their in-situ moisture content and reduce disturbance during transportation to the laboratory. The load carrying capacity of the gray shale encountered in the borings was evaluated in the field by performance of the Texas Department of Transportation's (TxDOT) Cone Penetration Test.

EMIL -1- HC081718

Dnlling and sampling were performed in general accordance with applicable ASTM and TxDOT

procedures.

4.0 LABORATORY TESTING

The Boring Logs and samples were reviewed by a geotechnical engineer who assigned soil

samples for testing. Tests were performed in the laboratory by technicians working under the direction of the engineer. Testing was performed in general accordance with applicable ASTM

procedures.

Liquid and Plastic Limit tests were performed on samples of the cohesive soils. These tests were

used in conjunction with moisture content tests for classification and estimating their volume

change potential. Unconfined compression test were performed on samples of cohesive soils to evaluate strength and hand penetrometer tests were performed to evaluate consistency.

The results of the laboratory tests are presented on the Boring Logs and in the Appendix.

5.0 SITE SUBSURFACE CONDITIONS

The conditions encountered at each boring location are depicted on Boring Logs in the Appendix.

Descriptions of each stratum with its approximated depth and thickness are provided. The depths reported on each log refer to the depth from the existing ground surface at the time the borings were performed.

Fill materials consisting of brown and tan silty clays with gravel and concrete were encountered at

the surface of Borings 1 and 2, and extended to depths of about 4 and 1 feet below existing

grades. Samples of the fill soils had Liquid Limits (LL) of 42 percent and Plasticity Indices (PI) of

27 and 28. The fill soils classified as CL according to the Unified Soil Classification System (USCS) and very stiff to hard in consistency.

Dark brown, brown, tan and gray silty clays, some with sand and gravel, were encountered

beneath the fills in Borings 1 and 2 and encountered at the surface of Boring 3. They extended to depths of about 21 Yz, 17 and 15 feet below existing grades in Borings 1, 2 and 3, respectively.

The silty clays had LL's of 39 to 48 percent; PI's of 26 to 32, classified as CL according to the USCS and was very stiff to hard in consistency in the upper portions becoming softer and moister

with depth.

Gray and tan shaley clays, clays and occasional gravelly clays were next encountered in the borings and extended to depth of about 28, 22Yz and 18Yz feet below existing grades in Boring 1, 2 and 3, respectively. They had LL's of 44 and 60 percent, PI's of 31 and 44, classified as CH and CL according to the USCS and were firm to stiff in consistency and generally saturated.

EWL -2- HC081718

Very dense, gray shale with limestone layers was next encountered in the borings at depths of about 18/'2 to 28 feet below existing grades and extended to the termination depths of about 30 to

40 feet below existing grades.

The soils encountered in the borings are considered to be active to highly active with respect to moisture-induced volume changes. Active clay soils will shrink and swell with variations in

seasonal moisture change.

6.0 GROUNDWATER

The borings were advanced in the dry using auger-drilling techniques. This process allows relatively accurate short-term observations of groundwater while drilling. Seepage was observed

in Borings 1, 2 and 3 while drilling at depths of about 23, 17 and 12 feet below existing grades,

respectively. A water level of about 16 feet was measured in the open borehole B-1, prior to

backfilling. Borings 2 and 3 were observed to be dry at dnlling completion.

Groundwater levels will seasonally fluctuate due to variations in the amount of precipitation,

evaporation, surface water runoff and fluctuation in the creek water levels. In addition,

groundwater conditions may change due to landscape irrigation, tree root demand and from leaking buried utilities.

7.0 ANALYSIS AND RECOMMENDATIONS

7.1 Foundation System

Based on the conditions encountered in the borings, a positive foundation system for the

proposed gabion wall base is straight drilled, reinforced concrete shafts founded in the gray shale that was encountered at depths of 28, 22/'2 and 18/'2 feet below existing grades.

Consideration may also be given to placing the bottom gabion baskets on a continuous concrete

footing extending into shale. The footings may be constructed of stacked gabion wall sections. Design parameters are presented below.

7.1.1 Straight Drilled Shafts

Straight drilled shafts penetrating the gray shales will use a combination of end bearing and skin friction in developing their load carrying capacity. We recommend an allowable end bearing pressure of 10,000 pounds per square feet (PSF) and an allowable skin friction value of 1,200

PSF for compressive loads. Allowable skin friction of 500 PSF can be considered on the overlying soils. The upper 5 feet of skin friction in the shaft should be neglected. These values

EMIL -3- HC081718

contain a safety factor of three (3). Higher skin friction values are applicable for that portion of the

shaft embedded in the gray shales below any temporary casing.

The shafts should penetrate the bearing stratum a minimum of 4 feet. Deeper penetrations may

be required to develop additional skin friction and/or uplift resistance. A minimum shaft diameter of 18 inches is recommended.

Adjacent shafts should maintain a minimum center to center spacing of 3.0 times the diameter of

the larger shaft. Closer spacing will require reductions in the skin friction values presented above, and possibly special installation sequences. As a general guide, the design skin friction

will vary linearly from the full value at a spacing of 3.0 diameters to 50 percent of the design value at 1.0 diameter. This firm should be contacted to review, on a case by case basis, shafts

requiring closer spacing.

Settlements for properly installed and constructed straight shafts in competent shales should be less than one-half inch.

7.1.2 Lateral Capacity

An allowable passive resistance of 2,000 PSF is recommended in the gray shale. An allowable

passive resistance of 400 PSF can be considered for the overlying soils. This lateral resistance is considered to act on the projected diameter of the shaft.

7.1.3 Soil Induced Uplift Loads

Since the lower gabion baskets will be resting near saturated soils there will be little uplift as a result of heave in the soils. For the conditions encountered at this site, minimum reinforcing equal to 0.5 percent of the shaft can be considered to resist soil induced uplift loads.

7.1.4 Dri lied Shaft Construction Considerations

Excavations for the shafts should be maintained in the dry. Preferably, concreting should closely

follow excavation to reduce caving and/or seepage problems. Groundwater seepage was observed in the borings and will likely be encountered during installation of some of the straight

shafts, particularly during wet seasonal cycles. Seepage rates may be sufficient to require the use of temporary casing for installation. The casing should be seated in the bearing stratum with

all water and most loose material removed prior to beginning the design penetration. Care must then be taken that a sufficient head of plastic concrete is maintained within the casing during extraction.

EMIL -4- HC081718

The concrete should have a slump of 6 inches plus or minus 1 inch and be placed in a manner to avoid striking the reinforcing steel during placement. Complete installation of individual shafts

should be accomplished in one day's operation and within an 8 hour period after the design penetration is begun. Close coordination of excavation and concreting will be required for

installation of straight shafts.

The drilled shaft design recommendations provided in this report are based on proper construction procedures, including maintaining a dry shaft excavation and proper cleaning of bearing surfaces prior to placing reinforcing steel and concrete. All drilled shaft installations

should be inspected by qualified geotechnical personnel to help verify the bearing stratum, the design penetration, and perform related duties.

7.2 Gabion Basket Walls

Based on the conditions encountered in the borings and the anticipated wall height provided by

Freese & Nichols, the toe of the gravity walls will be situated on shaley clays or silty clays and

may be designed with a maximum allowable bearing pressure of 1,500 PSF. A coefficient of friction of 0.35 is recommended for evaluating sliding resistance.

The retaining walls were analyzed as gravity walls placed on 3'(wide) x 1'(deep) stacked baskets

extending 1 foot into shale as described in the Global Slope Stability section below. They should be checked for bearing pressure, sliding and overturning. Resistance to sliding and overturning

should be checked for each section of wall for the full wall height.

Lateral earth pressures acting on the retaining walls will depend on the type of backfill material

used. Recommended lateral earth pressures expressed as equivalent fluid pressures are presented below for rigid and flexible walls with a level backfill. Rigid walls are not anticipated to deflect sufficiently to mobilize active earth pressures. Tied-back walls should be considered rigid.

Active earth pressures can be used where the top of the wall will deflect on the order of 0.5

percent of the wall height. Gravity walls should be designed for an active earth pressure condition.

EQUIVALENT FLUID PRESSURES

Backfill Material

On-site silty clays soils

Active (Flexible)

(pet)

75

At-Rest (Rigid) (pet)

95

Select Fill, with Liquid Limit less than 35 and PI less than 15

50 65

I

Granular backfill, less than 3% passing No. 200 sieve and less than 30% passing No. 40. Non-plastic

I

35

I

50

EIIIIL -5- HC081718

The wall backfill limits should extend outward at least 2 feet from the base of the wall and then

upward on a 1H:2V slope. For narrower backfill widths of granular or select fill soils, the

equivalent fluid pressures for the on-site soils should be used.

The lateral earth pressure values do not include surcharge loads due to overburden, foundation

influences, equipment, etc. Surcharge loads should be considered if they apply at the surface

above the wall within areas defined by an angle of 45 degrees from the base of the wall. A lateral pressure coefficient of 0.5 is recommended for uniformly distributed surcharge loads.

Wall backfill materials should be placed in loose lifts, less than 9 inches thick, and uniformly

compacted to a minimum density of 95 percent of ASTM 0698. Moisture content during placement of cohesive backfill should be within 0 to +5 percent of the optimum moisture content

as measured in test method ASTM 0698. Granular backfill should not be water jetted to achieve compaction and should be placed at a moisture content to allow the desired density to be achieved,

The top of the granular backfill should be protected by flatwork or a minimum of 2 feet of more clayey soils to help prevent surface infiltration.

The design recommendations presented above assume hydrostatic pressures will not develop

behind the wall. Drainage could be provided by the gabion design itself or by using a collector pipe or weep holes near the base of the wall. Gabion baskets, drains or weep holes should be properly filtered to minimize the potential for erosion through these drains and/or plugging of drain lines,

Settlement of the wall backfill should be anticipated. Piping and conduits through the fill should

be designed for potential soil loading due to fill settlement. Flatwork and sidewalks over the fills

may also settle. Backfill compacted to the density recommended above is anticipated to settle on the order of one half to one percent of the fill thickness.

7.3 Earthwork/Site Grading

The onsite soils are suitable for use in site grading. Imported fill material should be clean soil with

a Liquid Limit preferably less than 35 percent and no rock greater than 4 inches in maximum dimension. The fill materials should be free of vegetation and debris.

Prior to placing any fill, the areas to receive fill will need to be stripped and grubbed. Any soft or

pumping areas should be excavated to firm ground and properly backfilled as described below. Prior to placing any fills, the subgrade should be scarified to a minimum depth of 8 inches and recompacted to a minimum of 95 percent of ASTM D 698 at or above the optimum moisture content as determined by that test. The fill materials should then be spread in loose lifts, less

than 9 inches thick, and uniformly compacted to the same criteria. If filling is suspended and the

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subgrade becomes desiccated or rutted, it should be reworked prior to placement of a

subsequent lift.

If fill is to be placed on existing slopes, either natural or man-made, that are steeper than six

horizontal to one vertical (6: 1), then the fill materials should be benched into the existing slopes in such a manner as to provide a good contact between the two materials, break up potential sliding planes, and allow relatively horizontal lift placement.

Final slopes should be as flat as practical to reduce the possibility of creep and shallow slides.

Particularly in cut slopes, the shear strength of the site soils can deteriorate with time. Final side

slopes in cuts or fills of less than five feet in height may be as steep as 2H:1V. Taller sections will require considerably flatter slopes such that slopes of 4H: 1V.

7.4 Global Slope Stability

Proposed slope cross sections were provided by Freese & l\Jichols. One slope cross section in

the failure area was analyzed to serve as a baseline. Three additional cross sections at the final

slopes were developed at the locations nearest the performed borings. The worst case cross

section was then analyzed with the gabion basket wall at the finished slope (adjusted to a 1:1 slope) and again using a stacked gabion baskets as a key into the shale. The slope analyses

were performed using a computer code based on Bishop's Simplified Method after the proposed retention wall is constructed with water levels near current measured levels.

Residual shear strength parameters of 1,500 to 750 PSF in cohesion with an angle of internal

friction of 2 degrees were used for the upper silty clay in-situ soils at unsaturated to semi­

saturated states. The saturated soils were analyzed with shear strength parameters of 100 to 200 PSF with angles of internal friction of 2 to 4 degrees. A cohesion of 10,000 PSF was used to

model the shales. An angle of internal friction of 40 degrees in the limestone and a 3,500 PSF

shear strength (tensile) was used to model the gabion baskets. Strength parameters have a factor of safety of 3.

The cross-section diagram and results of the analyses are presented in Appendix B. A minimum factor of safety of about 2 was computed for the gabion basket wall structure placed on the

stacked basket key. These values are considered acceptable based on our engineering judgment and standard industry practice. The gabion wall structure placed upon a 1 to 1 slope

had a factor of safety slightly less than 1.5. Therefore we recommend that a key footing composed of either stacked gabion basket or concrete footing be extended at least 1 foot into the shale.

A factor of safety of less than 1 was calculated on the slope failure area. Factors of safety for the proposed slope sections were generally in the 1.5 range or greater. Therefore Rip/Rap will be

EK'L -7- HC081718

acceptable for these slopes. We recommend reducing proposed upper 5 feet of the slope to a

4H: 1V slope if possible to increase the slope stability at the Broadway East Slope Location.

7.5 Permanent Slopes

Final slopes should be as flat as practical to reduce the possibility of creep and shallow slides.

Taller sections will require considerably flatter slopes, such that slopes 10 feet or more in height ideally should have a maximum slope of 4H: 1V. Site improvements should be maintained well

back of the crest of slopes to reduce the effects of creep or shallow slides.

8.0 LIMITATIONS

The professional services performed for the preparation of this geotechnical report were

accomplished in accordance with current and locally accepted geotechnical engineering principles and practices. The recommendations presented in this report are based upon the data

obtained from the borings at the indicated locations and/or from other information discussed in this report. The possibility always exists that the subsurface conditions occurring between

borings, across the site, or due to seasonal/annual climatic cycles may vary from those encountered in the borings. The nature of these variations may not become evident until during

or after construction. Should subsurface conditions varying significantly from those described herein, EWL should be immediately notified to evaluate the effects on these recommendations

and so supplemental recommendations can be provided. EWL's services should also be retained

for the final review of design plans/specifications so comments can be made regarding interpretation of the geotechnical recommendations provided in this report.

The recommendations provided in this report were prepared for the exclusive use of our client. No warranties, expressed or implied, are intended or made. The information and

recommendations provided in this report are applicable only for the design of the types of structure(s) described in the Site and Project Information section of this report and should not be

used for any other structures, locations or for any other purposes. We should not be held responsible for the conclusions, opinions or recommendations made by others based upon the

information submitted in this report. If changes to the design and/or location of this project as outlined in this report are planned, the recommendations provided in this report shall not be

considered valid unless EWL reviews these changes and either verifies or amends this report in writing. Construction issues such as site safety support of excavations and dewatering

procedures are the responsibility of others.

The scope of services for this report does not include any environmental or biological assessments either specifically or implied. If the owner is concerned about the potential mold, fungi, bacteria, identification of contaminants or hazardous materials and conditions, etc., additional studies should be undertaken.

EW'L -8- HC081718

EWL's capabilities include a full range of construction material testing and observation services.

EWL should be retained to provide testing and observation during excavation, grading, foundation

and construction phases of this project.

We will retain the samples recovered from the borings on this project for a period of 30 days subsequent to the submittal date printed on this report. After the 30-day period, the samples will be discarded unless otherwise notified by the owner in writing.

EINL -9- HC081718

APPENDIX A

~ __ --~-~ ~ ~ L_____Broadway Road --------­

---------~----~ \ ~ . ...B-1 ~. c9

.-0 00' .~

C). ~~

7­

B-2 ... &"9

Glenview Drive

1:'0 O'.s'li

erG G,f

~'O~ .~

~'{)

......0 ",'"o

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. ,,~"'~0\'-:) .~0

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~-= ~~ ---=­ --_:: -0 LEG~ (-,,1 c;' _----------!

-~ 20<,r"9 LO(

/I

~ 5CALE

~;

~ 75 15C

FEET

~m'l:;eotechnica, Studies Group. Inc.

E~'::~~~"~~~'~~"i;l:";w;,", ,"eA DIV'SIOI '""Ie

EWL Project No. HC081718

PLAN OF BORINGS Erosion Control/Retaining Wall Structures

Big Fossil Creek at Glenview and Broadway Roads Haltom, Texas

__

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

EWL Geotechnical Studies Group Inc. 4501 Broadway Avenue Haltom City, Texas 76117 Telephone 817-759-9999 Fax 817-759-1888 CLI ENT t-t<i1tom City

PROJECT NUMBER HGQ8J718.

DATE STARTED 4/25108 COMPLETED 4/25/08

DRILLING METHOD Continuous Flight Auger

NOTESl3roadwCiY -E. sideof creek _.. _----- --~_._._--~------- -----------_.._---------­

I f--~ 0..';:: W·~

o

o C)

(/)

::0 f ­Z (5

(/)

" z 5 Q u I (D

I U W f ­

20

25

(J l-__-L-_.L...

MATERIAL DESCRIPTION

Brown and tan clay (FILL) - with gravel and concrete

Brown silty clay

Tan and gray silty clay

Gray and tan clay

Tan gravelly clay

Gray shale - with limestone layers

Bottom of hole at 40 feet---=::.=.::=.:..:..:....::.:..:..:.::.:.~:.:.......:_=__:_=_=.::_ L- ___.L_ ___L_ _L._ _L._ _'__..J....____J

FIGURE 2

BORING NUMBER B-1 PAGE 1 OF 1

PROJECT NAME Erosion ControIIRetainingWaIlStructl,l!~

PROJECT LOCATION Big Fossil Creel atGlenv!ElwIL~roa~ ..~.~..._----­

GROUND ELEVATION N/A

GROUND WATER LEVELS:

V AT TIME OF DRILLING 23.0 ft

• AT END OF DRILLING 16.0 ft

AFTER DRILLING

-I~ f-­W -' 0.. :2 <t if)

ST 21 42 14 28P"30

ST p" 4.5+

p" 4.5+ST 15 45 16 29

p" 45+ST 15

Qu" 6.0

p" 4.5+ 14ST

Qu"84

I i I

p" 4.5+ 15 40 12 28~ ST

i

I

p" 1.25 22 45 13 32~ ST

i

i i !

p" 0.25.- ST

I

I I

T" 4 5"/100 ~THD I

I T" 5.25"/100~THD

I

I

.JTHD T " 1.25"/100

2

--

,-----------------------------------------------------...,EWL Geotechnical Studies Group, Inc BORING NUMBER B-2 4501 Broadway Avenue PAGE 1 OF 1Haltom City Texas 76117 Telephone 817-759-9999 Fax 817-759-1888

CLIENT Haltom City PROJECT NAME Erosion Control/Retaining WaH §tru<;tl!!:..es__

PROJECT NUMBER HC081718 PROJECT LOCATION Big Fossil Creel at Glenview&E3ro~dway

DATE STARTED 4/25/08 COMPLETED 4/25/08 GROUND ELEVATION N/A

GROUND WATER LEVELS:

DRILLING METHOD Continuous Flight Auger V AT TIME OF DRILLING 17.0 ft

AT END OF DRILLING Dry

NOTES Broadway - W. side of creek AFTER DRILLING'--T:--r-- .------- ._---..._----- ._-- ----------­..if>

I 1- I I-~ 1t01Q..-S <to MATERIAL DESCRIPTION W a:..J o C) i

I I

O--+V"V"""'*~ . . .. ._

\

5

"--_"--

Brown and tan clay (FILL) ST

~\t\Iith 9~avel _ \Q~r15broVilQ::;ilty clay

Brown silty clay ST

Tan silty clay - with calcareous gravel and sand at 12' ST

ST

ST

ST

Gray shaley clay I

I

\~ SS1/

Gray shale i :- with limestone layers

>­z (3

::x)

8 T

co z L ~l

o U T D)

tj OJ

o ~.

W':.:J'--__

3: coo . _. alL' LL-C ::Jf- ZI ­':=c Uzu I- z gl- -x O~~~ CY~ g-~ UJW i=':= ~w Ue...­::J.3 -f- ::J­(/)~~(DU?Q)

UJ~ 1-0Oz O~ UJ~.c ~ ~ 9-~ >- UJz __ U 0 OJ '<"0 ~O ::::;..J :5::::; Wa: U 0... :5- zm.<=: 1:-: 0.. =i a o

0... LL. Z f- 0.. [y' a 0::

\ P =2 7~ 18 42 15 27

P =4.5+ 19 48 16 32

P =4.5+ 17

Qu = 5.8

P =4.5+

P =4.5+ 12 39 13 26

ro =4 5+

N = 37 17 44 13 31

--- ---------,-----1 I­ATTERBERG z

w~ IMIT W a:~ >- I ­

~ THO T = 8 75"/100

I I I

~THD T = 3"/100

I I I I

i

~ THD I T = 1 5"/100

Bottom of hole at 35 feet

-'-- ---'-_--'-_-'-_--'-_-'-_-'------J

FIGURE 3

EWL Geotechnical Studies Group, Inc 4501 Broadway Avenue Haltom City, Texas 76117 Telephone: 817-759-9999 Fax 817-759-1888 CLIENT ~altom City

PRO.IECT NUMBER. HC081?113

DATE STARTED 4/25/08 COMPLETED 4/25/08

DRILLING METHOD Continuous Flight Auger

MATERIAL DESCRIPTION

Dark brown silty clay

Tan and gray silty clay - with calcareous sand and gravel

Tan and gray shaley clay

Gray shale - with limestone layers

J)

z ~, ::J o o

T U

g Ll...'OL-__..L_..L

Bottom of hole at 30 feet.

BORING NUMBER B-3 PAGE 1 OF 1

PROJECT NAME Erosion Control/Retaining vyall Stru_cture~ _

PROJECT LOCATION Big Fossil Creel at Glenvie\IVJl.!3roadw~_

GROUND ELEVATION N/A

GROUND WATER LEVELS:

V AT TIME OF DRILLING 12.0 ft

AT END OF DRILLING Dry

AFTER DRILLING

If)

w D- o '" rn>- ~-..l- oU:: c

o· 'Q)w ~::o-cg~-' U)~~Q)U3Q)D­S ..c: ~ ~ .9-0...:;0:>

<! 65 ~~~~.b (/) .:-: .... :00

ZI-D-Q'OQ' ..

ST P = 4.5~

P = 4.0 ST Qu=3.7

ST P= 4.5+

ST P = 4.5+

P= 3.25ST

Qu 03.5

N = 14

T = 8"/100

T = 2.5"/100 ~TH[)

I I

I ' I

!

aJ THO T = 675"/100

~ t::c zu :::J,2, >­Q' 0

w~ Q'~

:::JI­I- z(/)w-I­OZ :;0:>0

U

21

19

14

14

23

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

I­ATTERBERG Z

I IT w I­>­ ZI­U -x O~gl- i=t: gw U~:::J­ (/):;0:> 1-0O~ <!- (/)z (/)

::J-' -,-' w D- 5- Z

D- i:i:

44 15 29

44 14 30

60 16 44

.J..- --L-_--L-_J-_J-_J-_-'--_

FIGURE 4

SOIL CLASSIFICATION CHART SYMBOLS TYPICAL

MAJOR DIVISIONS DESCRIPTIONSLETTER

WELL-GRADED GRAVELS, GRAVEL­CLEAN SAND MIXTURES. LITTLE OR NO GWGRAVEL GRAVELS FINES

AND GRAVELLY

POORLY-GRADED GRAVELS, SOILS GRAVEL - SAND MIXTURES, LITTLE GP

OR NO FINES

COARSE GRAINED GRAVELS WITH SILTY GRAVELS, GRAVEL - SAND­

MORE THAN 50% GM SILT MIXTURES OF COARSE

F SSOILS INE FRACTION ~()/;f;'7.::a*;x~v,~----t-----------l

RETAINED ON NO 4 SIEVE (APPRECIABLE ~ '/ ~ GC CLAYEY GRAVELS. GRAVEL - SAND­

AMOUNT OF FINES) ~ '/ y A;'/ CLAY MIXTURES tv: ;//W~

Q 0 " 0 0 0 ~ 0 Q

Q 0 " 0 0 0 Q Q

0000 Q 0 0 Q 0 o 0 0 0 ~ Q 0 0

Q 0 Q 0 0 0 Q"c WELL-GRADED SANDS, GRAVELLY ~ 0 0 0 0 0 0 <­~ 0 0 0 ~ 0 • 0 aCLEAN SANDS

Q 0 0 0 0 ~ " 0 SW SANDS. LITTLE OR NO FINES Q Q 0 0 0 Q ~ 0 0SAND 00000 •••MORE THAN 50%

o 0 Q Q 9 0 ~ 0 "AND LARGER THAN

OF MATERIAL IS SANDY

NO 200 SIEVE POORLY-GRADED SANDS, SOILS (LITTLE OR NO FINES) SP GRAVELLY SAND, LITTLE OR NO FINES

SIZE

SANDS WITH SILTY SANDS. SAND - SILT MORE THAN 50% SM MIXTURESFINES

OF COARSE FRACTION

PASSING ON NO 4 SIEVE (APPRECIABLE CLAYEY SANDS. SAND - CLAY

AMOUNT OF FINES) SC MIXTURES

INORGANIC SILTS AND VERY FINE SANDS. ROCK FLOUR. SILTY OR IVIL CLAYEY FINE SANDS OR CLAYEY

I !

•I SILTS WITH SLIGHT PLASTICITY

INORGANIC CLAYS OF LOW TOSILTS FINE LIQUID LIMIT MEDIUM PLASTICITY. GRAVELLY Af\ID LESS THAN 50 CL CLAYS, SANDY CLAYS. SILTY GRAINED CLAYS CLAYS. LEAN CLAYS

SOILS

ORGANIC SILTS AND ORGANIC OL SILTY CLAYS OF LOW PLASTICITY

MORE THAN 50% INORGANIC SILTS, MICACEOUS OR OF MATERIAL IS MH DIATOMACEOUS FINE SAND OR SMALLER THAN SILTY SOILS NO. 200 SIEVE

SIZE SILTS

LIQUID LIMIT INORGANIC CLAYS OF HIGH AND CHGREATER THAN 50 PLASTICITYCLAYS

ORGANIC CLAYS OF MEDIUM TO OH HIGH PLASTICITY. ORGANIC SILTS

PEAT. HUMUS, SWAMP SOILS WITH HIGHLY ORGANIC SOILS PT HIGH ORGANIC CONTENTS

GRAPH ... w .... w ... ..•~~

•• ~•• ~ ~ .•..•.... ....

p,-,~. 0 't' "-~ °l) "-.;'r).~c:Do ·.Je C)

P~ t"l 00 >.

NOTE DUAL SYMBOLS ARE USED TO INDICATE BORDERLINE SOIL CLASSIFICATIONS Figure 5

APPENDIX B

Failure Area X-Section Safety Factors

121.00

0.92

0.98

0.99

1.01

1.03

1.04 72.60 1.06

1.06

1.07I

1.0848.40

I I

24.20

0+ 24~20-- -,--­o 48.40 72.60 96.80 121.00 145.20 169.40 193.60

96.80

Broadway East Slope

121.001 ­

96.80

72.60

48.401

24.20j

O+--~---

Safety Factors

1.49

1.50

1.52

1.57

1.60

1.63

1.65

1.67

1.68

1.68

~j o 24.20 48.40 72.60 96.80 121.00 145.20 169.40 193.60

Broadway East Slope Safety Factors

121.00 1.47

1.48

1.48

1.48

1.50

1.50 72.60~ 1.52

1.54

1.55I

1.5648.40 1

I

24.20

I

I

01­o 24.20 48.40 72.60 96.80 121.00 145.20 169.40 193.60

96.80

Broadway East Slope w/Gabion Wall Safety Factors

121.00 1.95

2.00

2.0496.80

2.04

2.05

2.06

2.07

2.07

2.10

2.11

24.20 48.40 72.60 96.80 121.00 145.20 169.40 193.60

72.60 1

I

I48.40'

I

24.20

I

01­o

Broadway West Slope Safety Factors

121.00

96.80

72.60

48.40J

24.20

01­o 24.20 48.40 72.60 96.80 121.00 145.20 169.40 193.60

1.72

1.73

1.75

1.75

1.77

1.78

1.80

1.83

1.85

1.90

Glenview East Slope

141.90 I

I

113.521 ~~ I

I

85. 141

i

56.76

28.38

I

oJ-- ­ --------r----- ­ -- -­ ---T-----------, I I --,- ­

o 28.38 56.76 85.14 113.52 141.90 170.28

Safety Factors

2.62

2.84

2.97

3.19

3.34

3.40

3.41

3.50

4.03

9.90

I

198.66 ----j

227.04