Willow Park-SY091228 GEOTECHNICAL ENGINEERING REPORT
PROPOSED WILLOW PARK TOWNHOMES
COPPELL, TEXAS
Prepared Fora
MR. JASON ROSE
JR ROSE DEVELOPMENT COMPANIES
1207 BETHEL SCHOOL COURT
COPPELL, TEXAS 75019
DECEMBER 2009
PROJECT NO. 09 -15803
Rone Engineering
It
GEOTECHNICAL ENGINEERING
CONSTRUCTION MATERIALS TESTING
December 28, 2009
ENVIRONMENTAL CONSULTING
• FORENSIC ENGINEERING Mr. Jason Rose
JR Development Companies
1207 Bethel School Court
Coppell, Texas 75019
Re: Geotechnical Engineering Report
Proposed Willow Park Townhomes
Coppell, Texas
Rone Project No. 09 -15803
Dear Mr. Rose:
Submitted herewith are the results of a geotechnical investigation
conducted for the referenced project. This investigation was performed
in accordance with our proposal 09 -15017 dated December 1, 2009.
This report presents engineering analyses and recommendations for site
grading and foundations. Results of our field and laboratory investigation
are submitted in detail in the Appendix section of the report.
We appreciate the opportunity to be of service to you on this project.
Please contact us if you have any questions or need any additional
services.
Respectfully Submitted,
P-2/11
DALLAS /FORT WORTH
8908 AMBASSADOR ROW
DALLAS, TEXAS 75247 Mark L. McKay, P.E.
TELEPHONE 214- 630-9745
TELEPHONE 817 - 284 -1318 Seni r Geotechnical Engineer �: G . I ', I, 1
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FACSIMILE 214 -630 -9819 so � � � CY l VA
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7 701 , WESST YORK aa IJt ARK D. GRAY
600 . Gra , P. I ▪ 67901 • /
HOUSTON, TEXAS 77040 P 1 �` ` •• e � v
Vice Presid •nt 9 ,
TELEPHONE 713- 996 -9979 t, • •` .•°•"'4:-7 ri ° �` _
FACSIMILE 713- 996 -9972 WA, � v � �of•i f1�t _ � `° �♦
Texas Engine: i _ - irm Registration No. F - 157 ® ; ,.. e ,� Az .: =�
AUSTIN
4221 FREIDRICH LANE
SUITE 195
AUSTIN, TEXAS 78744
TELEPHONE 512- 462 -2733
FACSIMILE 512- 462 -1155
TABLE OF CONTENTS
Page
INTRODUCTION 1
FIELD AND LABORATORY INVESTIGATIONS 1
GENERAL SITE CONDITIONS 2
ANALYSIS AND RECOMMENDATIONS 3
RECOMMENDATIONS FOR THE PLACEMENT OF CONTROLLED EARTHFILL 7
CONSTRUCTION OBSERVATIONS 9
REPORT CLOSURE 9
APPENDIX A
Plate
BORING LOCATION DIAGRAM A.1
LOGS OF BORINGS A.2 -A.5
UNIFIED SOIL CLASSIFICATION SYSTEM A.6
KEY TO CLASSIFICATIONS AND SYMBOLS A.7
SWELL TEST RESULTS A.8
APPENDIX B
Page
FIELD OPERATIONS B -1
LABORATORY TESTING B -2
GEOTECHNICAL ENGINEERING REPORT
PROPOSED WILLOW PARK TOWNHOMES
COPPELL, TEXAS
INTRODUCTION
The project is located on the north side of Coppell Road, just east of State Highway 121 in Coppell,
Texas. We understand the project consists of developing 24 pad sites for townhomes, with
associated paved streets and drives. The town homes will be multi -story, wood -frame structures.
The loads for the proposed structures are estimated to be light. At the time of Rone's site
investigation the property was fairly level with a slight slope towards the drainage channel north of
the property. Trees had been removed from the area recently, leaving only field grasses.
Observations made during the site visit indicate that the site has been recently filled to achieve the
appearance of being level. Fills up to 4 feet appeared plausible based on observation of the
drainage channel embankment along the north side of the property. The general location and
orientation of the site are shown on the Boring Location Diagram, Plate A.1, in the Appendix section
of this report.
The principal purposes of this investigation were to evaluate the general soil conditions at the
proposed site and to develop geotechnical recommendations for the design and construction of
foundations. To accomplish its intended purposes, the study was conducted in the following phases:
(1) drill sample borings to evaluate the soil conditions at the boring locations and to obtain soil
samples; (2) conduct laboratory tests on selected samples recovered from the borings to establish the
pertinent engineering characteristics of the foundation soils; and (3) perform engineering analyses,
using field and laboratory data, to develop foundation design criteria.
FIELD OPERATIONS AND LABORATORY TESTING
Soil conditions were determined by a total of four sample borings. The quantity and location of the
borings was determined and provided by the client. The borings were drilled to depths of 20 feet
below grade at approximate 200 foot intervals in accordance with Home Buyer Warranty guidelines.
The borings were drilled in December 2009 and their approximate locations are shown on Plate A.1.
Sample depth, description of soils, and classification (based on the Unified Soil Classification
System) are presented on the Logs of Boring, Plates A.2 through A.S. Keys to terms and symbols
used on the logs are shown on Plates A.6 and A.7.
Project No. 09 -15803 Page 1
Laboratory soil tests were performed on selected samples recovered from the borings to verify visual
classification and determine the pertinent engineering properties of the soils encountered.
Classifications test results are presented on the Logs of Boring. Swell test results are shown on
Plate A.B.
Descriptions of the procedures used in the field and laboratory phases of this study are presented in
the Appendix of this report.
GENERAL SITE CONDITIONS
Subsurface Soil Conditions
According to published geologic maps, the site is located within the Quaternary terrace deposits and
alluvium associated with the ancestral Trinity River System overlying the Woodbine formation, very
near the contact with the Eagle Ford formation. The Quaternary sediments consist of clay, sand, silt
and gravel in variable and discontinuous depositional forms. Residual soils at the surface generally
consist of high plasticity clay, sandy clay and clayey sand, with a high shrink -swell potential. Sands,
clays, sandstones and shales generally compose the Woodbine formation. Dense and irregular
shaped masses of hard sandstone occur at random throughout the Woodbine. It is often difficult, if
not impossible, to trace a particular bed for any distance. Water is found at various levels in the
formation, some as perched tables in sand lenses. The Eagle Ford Shale formation consists of gray
and dark gray shale, and residual soils generally consist of high to very high plasticity clays and
shaley clays. Descriptions of the various strata and their approximate depths and thickness are
shown on the boring Togs. A brief summary of the stratigraphy indicated by the borings is given
below.
The borings generally encountered 4 to 6 feet of clayey sand, sandy clay fill containing small gravel,
limestone pieces and trace amounts of organic materials. Brown, reddish brown and tan sandy clay,
clayey sand, and silty sand with gravel at various depths followed the fill to a depth of 12 feet in
Boring B -4 and to the termination depths of borings B -1 through B -3 (20 feet). Gray sandy shale
was encountered in Boring B -4 at a depth of 12 feet and continued to the termination depth of 20
feet. Please refer to the Logs of Boring attached as Plates A.2 through A.5 for a more detail
representation of materials encountered at the boring locations.
The Plasticity Index of the samples tested ranged from non - plastic to 33, indicating negligible to high
soil plasticity. A high Plasticity Index is generally associated with a high potential for swelling.
Project No. 09 -15803 Page 2
Groundwater
The borings were advanced using auger drilling and intermittent sampling methods in order to
observe groundwater seepage levels. Groundwater was encountered at depths of about 12.5 to 16
feet during drilling. At completion of drilling, groundwater was measured between17.5 and 18.6 feet
in Borings B -1 and B -3. Borings B -2 and B -4 did not accumulate water during drilling and appeared
dry at completion. If left open for a greater period of time, it is likely all borings would have
presented measurable groundwater.
It is difficult to accurately predict the magnitude of subsurface water fluctuations that might occur
based upon short -term observations. Based on our experience with the Quaternary sediments,
groundwater can be encountered within and above the clays, sandy days, clayey sands and gravels,
particularly during wet periods of the year. Groundwater should be anticipated during the
construction phase of this project. Groundwater levels should be expected to fluctuate throughout
the year with variations in precipitation, runoff, and the water levels in nearby surface water features.
ANALYSIS AND RECOMMENDATIONS
Seismicity Site Class
The site class for seismic design is based on several factors that include soil profile (soil or rock),
shear wave velocity, density, relative hardness, and strength, averaged over a depth of 100 feet.
The borings for this project did not extend to a depth of 100 feet; therefore, we assumed the soil
conditions below the depth of the boring to be similar to those encountered at the termination depth
of the boring. Based on Section 1615.1.1 of the 2000 International Building Code, we recommend
using Site Class C (soft rock profile) for seismic design at this site.
Potential Vertical Soil Movements
Potential Vertical Movement calculations were performed in general accordance with the Texas
Department of Transportation (TxDOT) Method 124 -E. The TxDOT 124 -E method is empirical and
is based on the Atterberg limits and moisture content of the subsurface soils. Swell test results were
also used in the estimation of the PVR.
The Potential Vertical Rise (PVR) calculated using the TxDOT method ranges from about 1 to 2%
inches based on in -situ soil being at a dry antecedent condition and existing site grades at the time of
our drilling. At the time of drilling, the soils at the borings were in a relatively dry to moist condition.
Using on -site clay soils to raise site grades would increase the PVR values listed above. The
Project No. 09 -15803 Page 3
recommendations provided assume that no more than two feet of on -site clays or similar soils will be
used to raise grades to the finished pad elevations. If the grading plan is changed, we should be
contacted to revise our recommendations.
Foundation System
The soils at this site are suitable to support the residences on ground - supported foundations;
however, uncontrolled fills were found to be present on the order of 4 to 6 feet in depth. It will be
necessary to rework the upper 4 to 6 feet of the uncontrolled fills with engineering control to utilize
ground supported residential slab foundations (see the section titled "Subgrade Preparation" below
for guidelines). In addition, it may be prudent to perform additional soil borings on site to further
delineate the extent and nature of the fill material on -site. A ground - supported foundation can
consist of a conventionally reinforced beam and slab system, or a post- tensioned slab foundation
system. The foundation should be designed with exterior and interior grade beams adequate to
provide sufficient rigidity to the foundation system to sustain the vertical soil movements expected at
this site as described above.
A net allowable soil bearing pressure of 2,000 pounds per square foot may be used for design of all
grade beams bearing in density controlled fill. Grade beams should be founded a minimum of 18
inches compacted and tested fill. The bottom of the beam trenches should be free of any loose or
soft material prior to the placement of the concrete. All grade beams and floor slabs should be
adequately reinforced with steel to minimize cracking as normal movements occur in the foundation
soils.
According to the Post - Tension Institute (PTI), 3rd Edition, the design parameters for design of
foundations at this site are as follows:
Edge Moisture Variation Distance
Center Lift 9.0 feet
Edge Lift 5.0 feet
Differential Swell
Center Lift 1.3 inches
Edge Lift 1.9 inches
Project No. 09 -15803 Page 4
A moisture barrier should be used beneath the slab foundation in areas where floor coverings will be
utilized (such as, but not limited to, wood flooring, tile, linoleum, and carpeting).
Subgrade Preparation
Uncontrolled fill was encountered across the site ranging in depth from 4 to 6 feet from the existing
ground surface. In order to utilize ground supported foundation systems it will be necessary to
remove and replace the uncontrolled fill with engineering control as follows. The fill material should
be excavated and deleterious materials greater than 4 inches in size, or any organics should be
removed from the fill. The fill to be replaced should consist of material with at least 60 percent
passing the No. 4 sieve. The excavated soils may then be placed in loose lifts not exceeding 10
inches and compacted to at least 95 percent of the materials maximum dry density per the standard
Proctor test (ASTM D698) at moisture content of optimum to +4 percent above optimum.
Pavement Design Recommendations
The following pavement sections are a minimum recommended for this project based on a 20 -year
life design. They are based on our engineering judgment and experience with environmental
factors, including temperature, humidity, rainfall and swell characteristics of the soils.
We recommend a 6 -inch section for streets in residential communities. A minimum 7 -inch section is
recommended in areas receiving frequent heavy trucks and dumpsters. Concrete with a minimum
28 -day compressive strength of 3,500 pounds per square inch is recommended.
All topsoil, existing pavement and structures, vegetation, and any unsuitable materials should be
removed. The pavement subgrade should be proofrolled with a fully loaded tandem axle dump truck
or similar pneumatic -tire equipment to locate areas of loose subgrade. In areas to be cut, the
proofroll should be performed after the final grade is established. In areas to be filled, the proofroll
should be performed prior to placement of engineered fill and after the pavement subgrade is
established. Areas of loose or soft subgrade encountered in the proofroll should be removed and
replaced with engineered fill, or moisture conditioned (dried or wetted, as needed) and compacted in
place.
The clay soils are plastic and can undergo some volume change when subjected to moisture
variations. If the moisture contents of these upper soils reduce, they may shrink and cracks may
develop. If the moisture content of these materials increase, they could swell and lose strength.
Shrinkage, swelling, or strength loss could be detrimental to the proper function of the pavement.
Project No. 09-15603 Page 5
Lime treatment of clay subgrade is recommended to provide more uniform subgrade support and
improve these soil's strength characteristics. We recommend a minimum of 6 percent lime (by dry
soil weight) to a depth of 6 inches. Lime stabilization should be performed in accordance with Item
260, current Standard Specifications for Construction of Highways, Streets, and Bridges, Texas
Department of Transportation (TxDOT) or applicable standards. In lieu of lime treatment, the
pavement section may be increased by 1 -inch and lime treatment may be omitted. In the event
sandy soils are present at the final pavement subgrade elevation, it may be necessary to stabilize
the material by adding 4 to 6 percent by dry weight to the sandy soil subgrade. This option should be
considered if pumping or rutting is observed during subgrade preparation.
The final grades must be such that drainage is facilitated, and access of surface water to the
subgrade materials is prevented. Water can be introduced beneath the pavement through granular
materials used for aggregate bases and utility line embedment, and this water can cause differential
movement in the pavement. Aggregate base or a granular leveling course should not be used
beneath pavements, and all utilities should have clay plugs substituted for granular embedment
material at the edges of the pavement to reduce the risk of moisture access and possible swelling.
General
All grade supported slabs, outward swinging doors, outside stairs, etc. should be designed to
accommodate anticipated potential movements as presented in the section titled "Potential Vertical
Soil Movements" earlier in this report.
Every attempt should be made to limit the extreme wetting or drying of the subsurface soils because
swelling and shrinkage of these soils will result. Standard construction practices of providing good
surface water drainage should be used. A positive slope of the ground away from any foundation
should be provided. Also, ditches or swales should be provided to carry the run -off water both
during and after construction. Lawn areas should be watered moderately, without allowing the clay
soils to become too dry or too wet. Roof runoff should be collected by gutters and downspouts, and
should discharge away from the building.
Backfill for utility lines or along the perimeter beams should consist of site - excavated soil. If the
backfill is too dense or too dry, it will swell and a mound will form along the trench line. If the backfill
is too loose or too wet, it will settle and a sink will form along the trench line. Backfill should be
compacted as recommended in the section titled "Recommendations for the Placement of
Controlled Earth Fill" below.
Project No. 09 -15803 Page 6
Root systems from existing trees on -site will have dried and desiccated the clay soils, thereby giving
these clays very high swell potential. Post - construction moisture increases that naturally occur
beneath the surface will cause these soils to swell to a near maximum amount. The clay soils
surrounding trees and tree roots should be removed to a depth of at least 3 feet, moisture - conditioned
and re- compacted in place. Removal of the uncontrolled fills and replacement with moisture - density
control should also satisfy this requirement.
If granular material is used for embedment in utility trenches we recommend placing a clay plug, as
a replacement for the granular embedment, at the location where the city line is located, at the
location where the utility enters the structure and at other connections. The intent is to stop any free
moisture from passing through the granular embedment and entering the soil beneath the structure.
Root systems from trees and shrubs can draw a substantial amount of water from the clay soils at
this site, causing the clays to dry and shrink. This could cause settlement beneath grade - supported
slabs such as floors, walks and paving. Trees and large bushes should be located a distance equal
to at least one -half their anticipated mature height away from grade slabs.
All excavations should be sloped, shored, or shielded in accordance with OSHA requirements.
RECOMMENDATIONS FOR THE PLACEMENT OF
CONTROLLED EARTH FILL
Site Grading
Site grading operations, where required, should be performed in accordance with the
recommendations provided in this report. The site grading plans and construction should strive to
achieve positive drainage around all sides of the proposed building. Inadequate drainage around
structures built on -grade will cause excessive vertical differential movements to occur.
Preparation of Site
Preparation of the site for construction operations should include the removal and proper disposal of
all obstructions that would hinder preparation of the site for construction. These obstructions should
include all abandoned structures, foundations, debris, water wells, septic tanks and loose material.
It is the intent of these recommendations to provide for the removal and disposal of all obstructions
not specifically provided for elsewhere by the plans and specifications.
Project No. 09 -15803 Page 7
All concrete, trees, stumps, brush, abandoned structures, roots, vegetation, rubbish and any other
undesirable matter should be removed and disposed of properly. All vegetation should be removed
and the exposed surface should be scarified to an additional depth of at least 6 inches. It is the
intent of these recommendations to provide a loose surface with no features that would tend to
prevent uniform compaction by the equipment to be used.
All areas to be filled should be disced or bladed until uniform and free from large clods, brought to a
moisture content between optimum and 4 percentage points above the optimum moisture value, and
compacted to between 95 and 100 percent of optimum density in accordance with ASTM D698.
Fill Materials
Materials to be used for general site fill should consist of on -site material approved by the Soils
Engineer. Imported general site fill should have a liquid limit less than 60 and should be approved by
the Soils Engineer. There should be no roots, vegetation or any other undesirable matter in the soil,
and no rocks larger than 4 inches in diameter.
The fill material should be placed in level, uniform layers, which, when compacted, should have a
moisture content and density conforming to the stipulations called for herein. Each layer should be
thoroughly mixed during spreading to provide uniformity of the layer. The fill thickness should not
exceed 10 -inch loose lifts.
Prior to and in conjunction with the compacting operation, each layer should be brought to the
proper moisture content as determined by ASTM D698. We recommend the clay soils be moisture
conditioned to a moisture content that is between optimum and 4 percentage points above optimum.
After each layer has been properly placed, mixed and spread, it should be thoroughly compacted to
between 95 and 100 percent of Standard Proctor Density as determined by ASTM D698.
Density Tests
Field Density tests should be made by the Soils Engineer or his representative. Density tests should
be taken in each layer of the compacted material below the disturbed surface. If the materials fail to
meet the density specified, the course should be reworked as necessary to obtain the specified
compaction.
Project No. 09 -15803 Page a
CONSTRUCTION OBSERVATIONS
In any geotechnical investigation, the design recommendations are based on a limited amount of
information about the subsurface conditions. In the analysis, the geotechnical engineer must
assume the subsurface conditions are similar to the conditions encountered in the borings.
However, during construction quite often anomalies in the subsurface conditions are revealed.
Therefore, it is recommended that Rone Engineering Services, Ltd. be retained to observe
earthwork and foundation installation and perform materials evaluation and testing during the
construction phase of the project. This enables the geotechnical engineer to stay abreast of the
project and to be readily available to evaluate unanticipated conditions, to conduct additional tests if
required and, when necessary, to recommend alternative solutions to unanticipated conditions. Until
these construction phase services are performed by the project geotechnical engineer, the
recommendations contained in this report on such items as final foundation bearing elevations, final
depth of undercut of expansive soils for non - expansive earth fill pads, and other such subsurface -
related recommendations should be considered as preliminary.
It is proposed that construction phase observation and materials testing commence by the project
geotechnical engineer at the outset of the project. Experience has shown that the most suitable
method for procuring these services is for the owner to contract directly with the project geotechnical
engineer. This results in a clear, direct line of communication between the owner and the owner's
design engineers, and the geotechnical engineer.
REPORT CLOSURE
The analyses, conclusions and recommendations contained in this report are based on site
conditions as they existed at the time of the field investigation and further on the assumption that the
exploratory borings are representative of the subsurface conditions throughout the site; that is, the
subsurface conditions everywhere are not significantly different from those disclosed by the borings
at the time they were completed. If during construction, different subsurface conditions from those
encountered in our borings are observed, or appear to be present in excavations, we must be
advised promptly so that we can review these conditions and reconsider our recommendations
where necessary. If there is a substantial lapse of time between submission of this report and the
start of the work at the site, if conditions have changed due either to natural causes or to
construction operations at or adjacent to the site, or if structure locations, structural loads or finish
Project No. 09 -15803 Page 9
grades are changed, we urge that we be promptly informed and retained to review our report to
determine the applicability of the conclusions and recommendations, considering the changed
conditions and /or time lapse.
Further, it is urged that Rone Engineering Services, Ltd. be retained to review those portions of the
plans and specifications for this particular project that pertain to earthwork and foundations as a
means to determine whether the plans and specifications are consistent with the recommendations
contained in this report. In addition, we are available to observe construction, particularly the
compaction of structural fill, or backfill and the construction of foundations as recommended in the
report, and such other field observations as might be necessary.
This report has been prepared for the exclusive use of JR Rose Development Companies and its
designated agents for specific application to design of this project. We have used that degree of
care and skill ordinarily exercised under similar conditions by reputable members of our profession
practicing in the same or similar locality. No warranty, expressed or implied, is made or intended.
Project No. 09 -15803 Page 10
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Rone Engineering _
Project No. Boring No. Project Willow Park
09 -15803 B -1 Coppell, Texas
Location Water Observations
Groundwater seepage was encountered at a depth of about 16' while
Completion Completion drilling, and was remeasured at a depth of about 17.5' at the completion
Depth 20.0' Date 12 -14 -09 of drilling.
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Rone Engineering _
Project No, Boring No. Project Willow Park
09 -15803 B -2 _ Coppell, Texas
Location Water Observat
Groundwater seepage was encountered at a depth of about 15' while
Completion Completion drilling. Upon completion of drilling, the boring appeared to be dry.
Depth 20.0' Date 12 -14 -09
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5 silty, with small gravel, possible fill
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LOG OF BORING NO. B -2 Plate A.3
Rone Engineering _
Project No. Boring No. Project Willow Park
09 -15803 B -3 Coppell, Texas
Location Water Observations
Groundwater seepage was encountered at a depth of about 13' while
Completion Completion drilling, and was remeasured at a depth of about 18.6' at the completion
Depth 20.0' Date 12 -14 -09 of drilling.
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with broken limestone
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LOG OF BORING NO. B -3 Plate A.4
Rone Engineering _
Project No. Boring No. Project Willow Park
09 -15803 _ B -4 Coppell, Texas
Location Water Observations
Groundwater seepage was encountered at a depth of about 12.5' while
Completion Completion drilling. Upon completion of drilling, the boring appeared to be dry.
Depth 20.0' Date 12 -14 -09
Surface Elevation Type
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O
w 0 ? 0 N c i
O. A I 0 0 o LL 0
Q v Stratum Description , o >, c, w N
y c ` v V' 0 3 y 8c) c o �
0 0 3 � LL y =' > 3 U, - y •• an d c :'.' y o E,-
w d o - 9 w 1 R a) o- E csc E cats 'So c a C00
cc r= Ili c.F- a.w JJ aJ a E 2U D.� DU
' ' FILL: SANDY CLAY - brown, with limestone
j..; 2.0 21
pieces
.. FILL: SANDY CLAY - brown, with roots and 4.5+ 11 18143
ri, gravel
/.'
SANDY CLAY (CL) - brown and tan, silty, sandy 4.5+ 52 34 13 21 8
— �
5
4.5+ 55 42 12 30 11
SILTY SAND (SM) - reddish brown, with gravel X N=40 11
—10 --
- SHALE - gray, sandy E
- - -V 100 =3.25' 15
— 15 —'---r—
1 100 =1.75' 31
—20 Boring Terminated at 20 Feet
0
0
v
N
H
❑
o
w
z
O
K
a
0
M
0
m
0)
0 0
o
0
K
w
z
0
CC 0
0
J
co
LOG OF BORING NO. B -4 Plate A.5
Major Divisions Grp. Typical Names Laboratory Classification Rone Engineerin
Sym. Criteria
•
Well graded gravels, z
a) co
P2 w Ti) c GW gravel -sand mixtures, o cn C� D. greater than 4: Cc= (D�) between 1 and 3
-( .co 2 o little or no fines D,0 p D
0 C 0) C c
co .� o Poorly graded gravels, 0 Not meeting all gradation requirements
CD u- 0 U= GP gravel -sand mixtures, 2 for GW
° u, °) a a) ) v little or no fines 3 w ° ca in a i ca o 2 o Z N _o
.o ° z a � GM Silty gravels, gravel - > c co Liquid and Plastic limits Liquid and plastic
co " cv C c a) Q) sand - silt mixtures .N .9 Fa below "A" line or P.I. limits plotting in
CIS y c � to U) U) D hatched zone
a) a) .� s _c (B 4— C o -� greater than 4
c as a - ' -6 o . -.. L N 0 0 o, between 4 and 7
• L- 0 CO Ca c °) z 2 L and Plastic limits are borderline
0 o > Q o GC Clayey gravels, gravel E 0 0 above "A" line with P.I. cases requiring use
o .` E E - sand - clay mixtures o of dual symbols
L .� O 0 m m greater than 7 Y
c�
o E as ca ca
U a) a SW Well graded sands, 0) Ln v 40 (D30)
0 0 -- - o gravelly sands, little or c .o c C - go
greater than 6: C� D x D between 1 and 3
0 .( .N co 0 no fines -Q 1 0 60
. L' 0 C -°
c o a) ° Poorly graded sands � --E" °
� , — w o m Not meeting all gradation requirements
as
co
U SP gravelly sands, little or o • °' P for SW
°
o no fines 0 a, ° 0
o o n3 o Z ,, a o
C �' SM Silty sands sand silt . • o Liquid and Plastic limits Liquid and plastic
�
ia c mixtures P N r °- below "A" line or P.I. limits plotting
0 -. "- Q) `" less than 4 between 4 and 7
w ° 0, 0 o ° are borderline
o o E a o- o Clayey sands, sand E (J 2 ` Liquid and Plastic limits cases requiring use cis
E Q E SC 0 above "A" line with P.I. of dual symbols
co clay mixtures CD
— a)
❑ o as greater than 7
Inorganic silts and very fine
sands, rock flour, silty or
a) >, ML clayey fine sands, or clayey 60
ca silts with slight plasticity
_
0
c) E 'n Inorganic clays of low to
N C
as - o - C CL medium plasticity, gravelly
50
o ° • — -c clays, sandy clays, silty
Z —' Q clays, and lean clays CH
O (n J
Organic silts and organic
L OL
w silty clays of low plasticity 40 —
o
CD
-o , Inorganic silts, micaceous
c u) MH or diatomaceous fine sandy 30
0 ,
if) or silty soils, elastic silts � OH and MH 0
C0 ca v
a) E o in Inorganic clays of high 20 rQ'
E CH
a) (a plasticity, fat clays
w cf) :0 CL
_ 5
° cn .6 10
Organic clays of medium to
OH
= high plasticity, organic silts
C ML and OL
as
o
>. -- ° 0 10 20 30 40 50 60 70 80 90 100
O E c u .o Pt Peat and other highly
E E ° organic soils
I
UNIFIED SOIL CLASSIFICATION SYSTEM PLATE A.6
SOIL OR ROCK TYPES
Rone �� ~ ~
n������ u������������n
CLAY ��
. SAND-WELL GRADED
.
V FATCLAY '''' LIMESTONE-WEATHERED ur^r,r,
LEAN CLAY CONCRETE
r
SANDY CLAY FILL
/\
Shelby Auger Split
' Tube Spoon
/ / / / LIMESTONE rff09 GRAVEL
I toe:
V CLAYEY SAND
CLAYEYGRAVEL
SHALE MARL
_-_- -----
-__
8AND'P{}ORLY SILT Rock cono No
Core Pen Recovery
TERMS DESCRIBING CONSJSTENCY, CONDITION, AND STRUCTURE OF SOIL
Fine Grained Soils (More than nn% Passing No. zooSieve)
Consistency Penetrometer Reading, (tsf) Unconfined Compression, (psf)
Very Soft <o.n <1nun
Soft 0.5 to 1.0 1000 to 2000
Firm 1.0 to 2.0 2000 to 4000
Hard 2.0 to 4.0 4000 to 8000
Very Hard '4o > 8000
Coarse Grained Soils (More than 50% Retained on No. 200 Sieve)
Penetration Resistance Descriptive Item Relative Density
(Blows /Foot)
0 m4 Very Loose omzo%
4 to 10 Loose 20 to 40%
10 to 30 Medium Dense 40 to 70%
30 to 50 Dense 70 to 90%
Over 50 Very Dense 90 to 100%
Soil Structure
Calcareous Contains appreciable deposits of calcium carbonate; generaily nodular
Slickensided Having inclined planes of weakness that ate stick and glossy in appearance
Laminated Composed of thin Iayers of varying color or tex
Fissured Containing cracks, sometimes filled with fine sand or silt
Interbedded Composed of alternated layers of different soil types, usually in approximately equal proportions
TERMS DESCRIBING PHYSICAL PROPERTIES OF ROCK
Hardness and Degree of Cementation
Very Soft or Plastic Can be remolded in hand; corresponds in consistency up to hard in soils
Soft Can be scratched with fingernail
Moderately Hard Can be scratched easily with knife; cannot be scratched with fingernail
Hard Difficult to scratch with knife
Very Hard Cannot be scratched with knife
Poorly Cemented or Friable Easily crumbled
Cemented Bound together by chemically precipitated material; Quartz, calcite, dolomite, siderite, and iron oxide are common cementing
materials.
Degree of Weathering
Unweathered Rock in its natural state before being exposed to atmospheric agents
Slightly Weathered Noted predominantly by color change with no disintegrated zones
Weathered Complete color charige with zones of slightly decomposed rock
Extremely Weathered Complete color change with consistency, texture, and general appearance approaching soil
KEY TO CLASSIFICATION AND SYMBOLS PLATE A.7
SWELL TEST RESULTS
PROPOSED WILLOW PARK TOWNHOMES
COPPELL, TEXAS
RONE PROJECT NO. 09 -15803
Boring Sample Depth Liquid Plastic Plasticity Initial Final I Load Swell
(ft) Limit Limit Index MC ( %) MC ( %) (psf) ( %)
B -1 S -2 2 -4 46 13 33 16 19 360 0.6
B -2 S -4 6 -8 34 12 22 10 14 840 0.7
B -3 S -2 2 -4 25 15 10 7 8 360 0.0
B -4 S -3 4 -6 34 13 21 8 8 600 0.0
Plate A.8
FIELD OPERATIONS
Subsurface conditions were defined by four sample borings located as shown on the Boring
Location Diagram, Plate A.1. The borings were advanced between sample intervals using
continuous flight auger drilling procedures. The results of each boring are shown graphically on the
Logs of Boring, Plates A.2 through A.S. Sample depth, description, and soil classification based on
the Unified Soil Classification System are shown on the Logs of Boring. Keys to the symbols and
terms used on the Logs of Boring are presented on Plates A.6 and A.7.
Relatively undisturbed samples of cohesive soils were obtained with Shelby tube samplers in general
accordance with ASTM D -1587 at the locations shown on the Logs of Boring. The Shelby tube
sampler consists of a thin - walled steel tube with a sharp cutting edge connected to a head equipped
with a ball valve threaded for rod connection. The tube is pushed into the undisturbed soils by the
hydraulic pulldown of the drilling rig. The soil specimens were extruded from the tube in the field,
logged, tested for consistency with a hand penetrometer, sealed, and packaged to maintain "in situ"
moisture content.
The consistency of cohesive soil samples was evaluated in the field using a calibrated hand
penetrometer. In this test a 0.25 -inch diameter piston is pushed into the undisturbed sample at a
constant rate to a depth of 0.25 -inch. The results of these tests are tabulated at respective sample
depths on the logs. When the capacity of the penetrometer is exceeded, the value is tabulated as
4.5 +.
Samples of granular materials were obtained using split - barrel sampling procedures in general
accordance with ASTM D1586. In the split - barrel procedure, a disturbed sample is obtained in a
standard 2 inch OD split barrel sampling spoon driven into 18 inches into the ground using a 140 -
pound hammer falling freely 30 inches. The number of blows for the last 12 inches of a standard 18-
inch penetration is recorded as the Standard Penetration Test resistance (N- value). The N- values are
recorded on the boring logs at the depth of sampling. The samples were sealed and returned to our
laboratory for further examination and testing.
Groundwater observations during and after completion of the boring are shown on the upper right of
the boring log. Upon completion of the boring, the boreholes were backfilled from the top and
plugged at the surface.
B -1
LABORATORY TESTING
General
Laboratory tests were performed to define pertinent engineering characteristics of the soils
encountered. The laboratory tests included moisture content, Atterberg limits determination
unconfined compression, dry unit weight, free swell and visual classification.
Classification Tests
Classification of soils was verified by natural moisture content and Atterberg limits determinations.
These tests were performed in general accordance with American Society for Testing and Materials
(ASTM) procedures. The Atterberg limits and natural moisture content determinations are
presented at the respective sample depths on the Logs of Boring.
Strength Tests
Unconfined compression tests were performed on selected samples of cohesive soils. In the
unconfined compression test, a cylindrical specimen is subjected to axial Toad at a constant rate of
strain until failure occurs. Test procedures were in general accordance with ASTM D2166. Strengths
determined by this test are tabulated at their respective sample depths on the logs of borings. Results
of natural moisture content and dry unit weight determinations are also tabulated at the respective
sample depths on the logs.
Free Swell Tests
Selected samples of the near - surface cohesive soils were subjected to free swell tests. In the free
swell test, a sample is placed in a consolidometer and subjected to the estimated overburden
pressure. The sample is then inundated with water and allowed to swell. Moisture contents are
determined both before and after completion of the test. Test results are recorded as the percent
swell, with initial and final moisture content.
B -2