HomeMy WebLinkAboutSoils Report 01.24.2018H-PKUMAR
Geotechnical Engineering 1 Engineering Geology
Materials Testing 1 Environmental
5020 County Road 154
Glenwood Springs, CO 81601
Phone: (970) 945-7988
Fax: (970) 945-8454
Email: hpkglenwood@kumarusa.com
Office Locations: Parker, Glenwood Springs, and Silverthorne, Colorado
RECEIVED
APR 2 0 2018
GARFIELD COUNTY
COMMUNITY DEVELOPMENT
SUBSOIL STUDY
FOR FOUNDATION DESIGN
PROPOSED RESIDENCE
TBD (NEAR 6001) COUNTY ROAD 214
GARFIELD COUNTY, COLORADO
PROJECT NO. 17-7-885
JANUARY 24, 2018
PREPARED FOR:
DAVID AND KARA HERRALA
6607 COUNTY ROAD 214
NEW CASTLE, CO 81647
(dkherralaco @ msn,com)
TABLE OF CONTENTS
PURPOSE AND SCOPE OF STUDY - 1 -
PROPOSED CONSTRUCTION - 1 -
SITE CONDITIONS - 1 -
FIELD EXPLORATION - 2 -
SUBSURFACE CONDITIONS - 2 -
FOUNDATION BEARING CONDITIONS - 3 -
DESIGN RECOMMENDATIONS - 3 -
FOUNDATIONS - 3 -
FOUNDATION AND RETAINING WALLS - 5 -
FLOOR SLABS - 6 -
UNDERDRAIN SYSTEM - 8 -
SITE GRADING - 8 -
SURFACE DRAINAGE - 9 -
LIMITATIONS - 9 -
FIGURE 1 - LOCATION OF EXPLORATORY BORINGS
FIGURE 2 - LOGS OF EXPLORATORY BORINGS
FIGURE 3 - LEGEND AND NOTES
FIGURES 4 and 5 - SWELL -CONSOLIDATION TEST RESULTS
TABLE 1- SUMMARY OF LABORATORY TEST RESULTS
H -P KUMAR
Project No. 17-7-885
PURPOSE AND SCOPE OF STUDY
This report presents the results of a subsurface study for a proposed residence to be located near
6001 County Road 214 (Peach Valley Road), Garfield County, Colorado. The project site is
shown on Figure 1. The purpose of the study was to develop recommendations for foundation
design. The study was conducted in accordance with our agreement for geotechnical engineering
services to David and Kara Herrala, dated December 20, 2017.
A field exploration program consisting of exploratory borings was conducted to obtain
information on subsurface conditions. Samples of the subsoils and bedrock obtained during the
field exploration were tested in the laboratory to determine their classification, compressibility or
swell and other engineering characteristics. The results of the field exploration and laboratory
testing were analyzed to develop recommendations for foundation types, depths and allowable
pressures for the proposed building foundation. This report summarizes the data obtained during
this study and presents our conclusions, design recommendations and other geotechnical
engineering considerations based on the proposed construction and the subsoil conditions
encountered.
PROPOSED CONSTRUCTION
The proposed residence will be a one-story structure over a walkout basement with an attached
slab -on -grade garage. Ground floor is proposed to be slab -on -grade. Grading for the structure is
assumed to be relatively minor with cut depths between about 3 to 10 feet. We assume relatively
light foundation loadings, typical of the proposed type of construction.
If building loadings, location or grading plans change significantly from those described above,
we should be notified to re-evaluate the recommendations contained in this report.
SITE CONDITIONS
The site was vacant, except for a water well, at the time of our field exploration. The site is
accessed by a recently improved driveway cut into the hillside north of County Road 214. The
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Project No. 17-7-885
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terrain is hilly and located on the south face of the Grand Hogback monocline. The ground
surface slope is moderate down to the southwest with an elevation change of about 10 to 12 feet
across the building area. Vegetation in the area consisted of pinyon and juniper trees, sagebrush,
grass and weeds.
FIELD EXPLORATION
The field exploration for the project was conducted on January 5, 2018. Two exploratory
borings were drilled at the locations shown on Figure 1 to evaluate the subsurface conditions.
The borings were advanced with a 4 -inch diameter continuous flight auger powered by a truck-
mounted CME -45B drill rig and logged by a representative of H-P/Kumar.
Samples of the subsurface materials were taken with a 2 -inch I.D. spoon sampler. The sampler
was driven into the subsurface materials at various depths with blows from a 140 pound hammer
falling 30 inches. This test is similar to the standard penetration test described by ASTM
Method D-1586. The penetration resistance values are an indication of the relative density or
consistency of the subsoils and hardness of the bedrock. Depths at which the samples were taken
and the penetration resistance values are shown on the Logs of Exploratory Borings, Figure 2.
The samples were returned to our laboratory for review by the project engineer and testing.
SUBSURFACE CONDITIONS
Graphic logs of the subsurface conditions encountered at the site are shown on Figure 2. Below
about Y2 foot of organic topsoil, the subsoils consist of very stiff to hard, sandy silty clay. At a
depth of about 17 to 18 feet, weathered claystone bedrock was encountered that transitioned to
very hard claystone/siltstone bedrock below a depth of about 23 feet in Boring 1. The very stiff
to hard clay soils and weathered claystone can possess an expansion potential when wetted.
Laboratory testing performed on samples obtained during the field exploration included natural
moisture content and density and finer than sand size gradation analyses. Swell -consolidation
testing was performed on relatively undisturbed drive samples of the clay soils. The swell -
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Project No. 17-7-885
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consolidation test results, presented on Figures 4 and 5, indicate
low compressibility under
relatively light surcharge loading and a low to high expansion potential
when wetted under a
constant Light surcharge. The laboratory testing is summarized in Table 1.
No free water was encountered in the borings at the time of drilling and the subsoils and bedrock
were slightly moist.
FOUNDATION BEARING CONDITIONS
The clay soils and likely the weathered claystone encountered at the site are expansive. Shallow
foundations placed on the expansive soils similar to those encountered at this site can experience
movement causing structural distress if the clay bearing soil is subjected to changes in moisture
content. A drilled pier foundation can be used to penetrate the expansive materials to place the
bottom of the piers in a zone of relatively stable moisture conditions and make it possible to load
the piers sufficiently to resist uplift movements. Using a pier foundation, each column is
supported on a single drilled pier and the building walls are founded on grade beams supported
by a series of piers. Loads applied to the piers are transmitted to the bedrock partially through
peripheral shear stresses and partially through end bearing pressure. In addition to their ability to
reduce differential movements caused by expansive materials, straight -shaft piers have the
advantage of providing relatively high supporting capacity and should experience a relatively
small amount of movement.
DESIGN RECOMMENDATIONS
FOUNDATIONS
Based on the data obtained during the field and laboratory studies, we recommend straight -shaft
piers drilled into the bedrock be used to support the proposed structure.
The design and construction criteria presented below should be observed for a straight -shaft pier
foundation system:
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Project No. 17-7-885
1)
-4.
The piers should be designed for an allowable end bearing pressure of 30,000 psf
and an allowable skin friction value of 3,000 psf
for that portion of the pier in
hard to very hard bedrock.
2) Piers should also be designed for a minimum dead load pressure of 12,000 psf
based on pier end area only. If the minimum dead load requirement cannot be
achieved, the pier length should be extended beyond the minimum penetration to
make up the dead load deficit. This can be accomplished by assuming one-half
the allowable skin friction value given above acts in the direction to resist uplift.
3) Uplift on the piers from structural loading can be resisted by utilizing 75% of the
allowable skin friction value plus an allowance for the weight of the pier.
4)
Piers should be a minimum diameter of 12 inches and penetrate at least three pier
diameters into the hard bedrock. A minimum penetration of 6 feet into the hard
bedrock and a minimum pier length of 20 feet are recommended.
5) Piers should be designed to resist lateral loads assuming a modulus of horizontal
subgrade reaction of 50 tcf in the clay soils and a modulus of horizontal subgrade
reaction of 200 tcf in the bedrock. The modulus values given are for a long, 1
foot wide pier and must be corrected for pier size.
6) Piers should be reinforced their full length with
inches of pier perimeter to resist tension created by the swelling materials.
7) A 4 -inch void form should be provided beneath grade beams to prevent the
one #5 reinforcing rod for each 14
swelling soil from exerting uplift forces on the grade beams and to concentrate
pier loadings. A void form should also be provided beneath pier caps.
8) Concrete utilized in the piers should be a fluid mix with sufficient slump so that
concrete will fill the void between the reinforcing steel and the pier hole.
9) Pier holes should be properly cleaned prior to the placement of concrete. The
drilling contractor should mobilize equipment of sufficient size to effectively drill
through possible coarse soils and cemented bedrock zones.
10) Although free water was not encountered in the borings drilled at the site, some
seepage in the pier holes may be encountered during drilling. Dewatering
equipment may be required to reduce water infiltration into the pier holes. If
water cannot be removed prior to placement of concrete, the tremie method
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Project No. 17-7-885
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should be used after the hole has been cleaned of spoil. In no case should
concrete free fall into more than 3 inches of water.
11) Care should be taken to prevent the forming of mushroom -shaped tops of the
piers which can increase uplift force on the piers from swelling soils.
12)
A representative of the geotechnical engineer should observe pier drilling
operations on a full-time basis.
FOUNDATION AND RETAINING WALLS
Foundation walls and retaining structures which are laterally supported and can be expected to
undergo only a slight amount of deflection should be designed for a lateral earth pressure
computed on the basis of an equivalent fluid unit weight of 60 pcf for backfill consisting of the
on-site soils and 50 pcf for backfill consisting of imported granular material. Cantilevered
retaining structures which are separate from the residence and can be expected to deflect
sufficiently to mobilize the full active earth pressure condition should be designed for a lateral
earth pressure computed on the basis of an equivalent fluid unit weight of 50 pcf for backfill
consisting of the on-site soils and 40 pcf for backfill consisting of imported granular material.
All foundation and retaining structures should be designed for appropriate hydrostatic and
surcharge pressures such as adjacent footings, traffic, construction materials and equipment. The
pressures recommended above assume drained conditions behind the walls and a horizontal
backfill surface. The buildup of water behind a wall or an upward sloping backfill surface will
increase the lateral pressure imposed on a foundation wall or retaining structure. An underdrain
should be provided to prevent hydrostatic pressure buildup behind walls.
Backfill should be placed in uniform lifts and compacted to at least 90% of the maximum
standard Proctor density at near optimum moisture content. Backfill placed in pavement areas
should be compacted to at least 95% of the maximum standard Proctor density. Care should be
taken not to overcompact the backfill or use large equipment near the wall since this could cause
excessive lateral pressure on the wall. Some settlement of deep foundation wall backfill should
be expected even if the material is placed correctly and could result in distress to facilities
constructed on the backfill.
H -P *_ KU MAR
Project No. 17-7-885
a maximum allowable bearing pressure of 2,500 psf.
crawlspace below be used for all floors in the building
-6 -
We recommend imported granular soils for backfilling foundation walls and retaining structures
because their use results in lower lateral earth pressures and the backfill will improve the
subsurface drainage.
Subsurface drainage recommendations are discussed in more detail in the
"Underdrain System" section of this report. Imported granular wall backfill should contain less
than 15% passing the No. 200 sieve and have a maximum size of 6 inches. The granular backfill
behind foundation and retaining walls should extend to an envelope defined as a line sloped up
from the base of the wall at an angle of at least 30 degrees from the vertical. The upper 2 feet of
the wall backfill should be a relatively impervious on-site soil or a pavement structure should be
provided to prevent surface water infiltration into the backfill.
Shallow spread footings may be used for support of retaining walls separate from the residence,
provided some differential movement and distress can be tolerated. Footings should be sized for
The lateral resistance of retaining wall
footings 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 a coefficient of friction of 0.30. Passive pressure against
the sides of the footings can be calculated using an equivalent fluid unit weight of 300 pcf. The
coefficient of friction and passive pressure values recommended above assume ultimate soil
strength. Suitable factors of safety should be included in the design to limit the strain which will
occur at the ultimate strength, particularly in the case of passive resistance. Fill placed against
the sides of the footings to resist lateral loads should be compacted to at least 95% of the
maximum standard Proctor density at a moisture content near optimum.
FLOOR SLABS
Floor slabs present a problem where expansive materials are present near bearing elevation
because sufficient dead load cannot be imposed on the slab to resist the uplift pressure generated
when the bearing materials are wetted and expand.
We recommend that structural floors with
movement.
that will be sensitive to upward
H -P KUMAR
Project No. 17-7-885
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Slab -on -grade construction may be used in the garage area provided the risk of distress is
understood by the owner. We recommend placing at least 3 feet of nonexpansive structural fill
below floor slabs to help mitigate slab movement due to expansive soils.
To reduce the effects of some differential movement, nonstructural floor slabs should be
separated from all bearing walls, columns and partition walls with expansion joints which allow
unrestrained vertical movement. Interior non-bearing partitions resting on floor slabs should be
provided with a slip joint at the bottom of the wall so that, if the slab moves, the movement
cannot be transmitted to the upper structure. This detail is also important for wallboards,
stairways and door frames. Slip joints which allow at least 1' inches of vertical movement are
recommended. Floor slab control joints should be used to reduce damage due to shrinkage
cracking. Joint spacing and slab reinforcement should be established by the designer based on
experience and the intended slab use.
A minimum 4 -inch layer of free -draining gravel should be placed immediately beneath below
grade slabs -on -grade. This material should consist of minus 2 -inch aggregate with less than 50%
passing the No. 4 sieve and less than 2% passing the No. 200 sieve. The free -draining gravel
will aide in drainage below the slabs and should be connected to the underdrain system.
Required fill beneath slabs should consist of a suitable imported granular material, excluding
topsoil and oversized rocks. The suitability of structural fill materials should be evaluated by the
geotechnical engineer prior to placement. The fill should be spread in thin horizontal lifts,
adjusted to at or above optimum moisture content, and compacted to 95% of the maximum
standard Proctor density. All vegetation, topsoil and loose or disturbed soil should be removed
prior to fill placement.
The above recommendations will not prevent slab heave if the expansive soils underlying slabs -
on -grade become wet. However, the recommendations will reduce the effects if slab heave
occurs. All plumbing lines should be pressure tested before backfilling to help reduce the
potential for wetting.
H -P KUMAR
Project No. 17-7-885
8
UNDERDRAIN SYSTEM
Although groundwater was not encountered during our exploration, it has been our experience in
the area and where clay soils are present that local perched groundwater may develop during
times of heavy precipitation or seasonal runoff. Frozen ground during spring runoff can create a
perched condition. Therefore, we recommend below -grade construction, such as crawlspace and
basement areas, be protected from wetting by an underdrain system. The drain should also act to
prevent buildup of hydrostatic pressures behind foundation walls.
The underdrain system should consist of a drainpipe surrounded by free -draining granular
material placed at the bottom of the wall backfill. The drain lines should be placed at each level
of excavation and at least 1 foot below lowest adjacent finish grade and sloped at a minimum 1%
grade to a suitable gravity outlet. Free -draining granular material used in the drain system
should consist of minus 2 -inch aggregate with less than 50% passing the No. 4 sieve and less
than 2% passing the No. 200 sieve. The drain gravel should be at least 2 feet deep. Void form
below the grade beams can act as a conduit for water flow. An impervious liner such as 20 mil
PVC may be placed below the drain gravel in a trough shape and attached to the grade beam with
mastic to keep drain water from flowing beneath the grade beam and to other areas of the
building.
SITE GRADING
Fill material used inside building limits should consist of non -expansive, granular material. Fill
should be placed and compacted to at least 95% of the maximum standard Proctor density near
the optimum moisture content. Fill should not contain concentrations of organic matter or other
deleterious substances. The geotechnical engineer should evaluate the suitability of proposed fill
materials prior to placement. In fill areas, the natural soils should be stripped of topsoil, scarified
to a depth of 6 inches, adjusted to a moisture content near optimum and compacted to provide a
uniform base for fill placement. The natural soil encountered during this study will be expansive
when placed in a compacted condition. Consequently, these materials should not be used as fill
material directly beneath building areas. The natural soils can be used for fill material outside
building areas.
H -P KUMAR
Project No. 17-7-885
-9 -
SURFACE DRAINAGE
The following drainage precautions should be observed during construction and maintained at all
times after the residence has been completed:
1) Excessive wetting or drying of the foundation excavations and underslab areas
should be avoided during construction. Drying could increase the expansion
potential of the clay soils.
2) Exterior backfill should be adjusted to near optimum moisture and compacted to
at least 95% of the maximum standard Proctor density in pavement areas and to at
least 90% of the maximum standard Proctor density in landscape areas. Free -
draining wall backfill should be covered with filter fabric and capped with about 2
feet of the on-site soils to reduce surface water infiltration.
3) The ground surface surrounding the exterior of the building should be sloped to
drain away from the foundation in all directions. We recommend a minimum
slope of 12 inches in the first 10 feet in unpaved areas and a minimum slope of 3
inches in the first 10 feet in paved areas.
4) Roof downspouts and drains should discharge well beyond the limits of all
backfill. Graded swales should have a minimum invert slope of 3%.
5) Landscaping which requires regular heavy irrigation should be located at least 10
feet from foundation walls. Consideration should be given to use of xeriscape to
reduce the potential for wetting below the building caused by landscape irrigation.
LIMITATIONS
This study has been conducted in accordance with generally accepted geotechnical engineering
principles and practices in this area at this time. We make no warranty either express or implied.
The conclusions and recommendations submitted in this report are based upon the data obtained
from the exploratory borings drilled at the locations indicated on Figure 1, the proposed type of
construction and our experience in the area. Our services do not include determining the
presence, prevention or possibility of mold or other biological contaminants (MOBC) developing
in the future. If the client is concerned about MOBC, then a professional in this special field of
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Project No. 17-7-885
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practice should be consulted. Our findings include interpolation and extrapolation of the
subsurface conditions identified at the exploratory borings and variations in the subsurface
conditions may not become evident until excavation is performed. If conditions encountered
during construction appear to be different from those described in this report, we should be
notified at once so re-evaluation of the recommendations may be made.
This report has been prepared for the exclusive use by our client for design purposes. We are not
responsible for technical interpretations by others of our information. As the project evolves, we
should provide continued consultation and field services during construction to review and
monitor the implementation of our recommendations, and to verify that the recommendations
have been appropriately interpreted. Significant design changes may require additional analysis
or modifications of the recommendations presented herein. We recommend on-site observation
of excavations and foundation bearing strata and testing of structural fill by a representative of
the geotechnical engineer.
Sincerely,
H -P% KUMAR
Steven L. Pawlak, P
Reviewed by:
Daniel E. Hardin, P.E.
SLP/kac
H -P = KUMAR
Project No. 17-7-885
/ ) f
f
/ /
1
I / I
, i
.' f I I
TO PEACH VALLEY RD r
r.(CR 214) f
20 0 20 -AL1
APPROXIMATE SCALE-FCCT
17-7-885
Kumar & Associates
LOCATION OF EXPLORATORY BORINGS
Fig. 1
5905
5900
5895
BORING 1
EL. 5897'
BORING 2
EL. 5902'
36/12
WC=6.8
DD=118
r
/
//J 55/12
// 18/12 //
/ WC=6.4
r
// DD=109 /
l -200=82 /
/
/ /
/ /
//J 48/12 //1 38/12
/ WC=7.6 / WC=5.4
5890 / / DD=112 / D0=120
/ r
/
// /
/ /
/ /
/
//-1 26/12 / 38/12
/
5885 / /
5880
5875
587D
5865
/1 41/12
/ WC=9.3
// DD=119
32/12
50/5
50/3
/
"7-1 70/12
5905-
905--
5900
5900
5895
5895
5890 --
5885
5880
5875
5870 --
5865
1-
w
w
LJ -
_J
0
w
w
17-7-885
H -P- KUMAR
LOGS OF EXPLORATORY BORINGS
Fig. 2
LEGEND
/
TOPSOIL; ORGANIC SANDY SILT AND CLAY, DARK BROWN.
CLAY (CL); SANDY, SILTY IN UPPER FEW FEET, VERY STIFF TO HARD, SLIGHTLY MOIST,
BROWN, LOW TO MEDIUM PLASTICITY WITH DEPTH, SLIGHTLY CALCAREOUS.
WEATHERED CLAYSTONE; MEDIUM HARD TO HARD, SLIGHTLY MOIST TO MOIST, GRAY.
1 CLAYSTONE/SILTSTONE BEDROCK; VERY HARD, SLIGHTLY MOIST, MIXED RED—BROWN.
RELATIVELY UNDISTURBED DRIVE SAMPLE; 2—INCH I.D. CALIFORNIA LINER SAMPLE.
/J
18/12 DRIVE SAMPLE BLOW COUNT. INDICATES THAT 18 BLOWS OF A 140—POUND HAMMER
FALLING 30 INCHES WERE REQUIRED TO DRIVE THE CALIFORNIA SAMPLER 12 INCHES.
NOTES
1. THE EXPLORATORY BORINGS WERE DRILLED ON JANUARY 5, 2018 WITH A 4—INCH DIAMETER
CONTINUOUS FLIGHT POWER AUGER.
7. 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 OBTAINED BY INTERPOLATION BETWEEN
CONTOURS ON THE SITE PLAN PROVIDED.
4. THE EXPLORATORY BORING LOCATIONS AND ELEVATIONS 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. GROUNDWATER WAS NOT ENCOUNTERED IN THE BORINGS AT THE TIME OF DRILLING.
7. LABORATORY TEST RESULTS:
WC = WATER CONTENT (%) (ASTM D 2216);
DD = DRY DENSITY (pc f) (ASTM D 2216);
—200= PERCENTAGE PASSING NO. 200 SIEVE (ASTM D 1140).
17-7-885
H -P- KUMAR]
LEGEND AND NOTES
Fig. 3
�• 2
CONSOLIDATION - SWELL
— 2
— 3
2
SAMPLE OF: Sandy Silty Clay
FROM: Boring 1 ® 5'
WC = 7.6 %, DD = 112 pcf
1.0 APPLIED PBESSUItt - Y,ST �{
mn. 1.11 rnWI.t* is IN.
w b
wwin t.nr tntirq report
FoO ner poCM, a..p
In
k W med
I..it..nt at Edna. epyr...r .F
%.0..r ..,f A...G.In. Fre. Soot
^
.n.dxmhe tntho. wn.rmr.
M. -e. ,nx *eV 0»11111.
EXPANSION UNDER CONSTANT
PRESSURE UPON WETTING
SAMPLE OF: Sandy Clay
FROM: Boring 1 ® 15'
WC = 9.3 %, DD = 119 pcf
EXPANSION UNDER CONSTANT
PRESSURE UPON WETTING
1.0 APPiJED PRESSURE — RSF 10
100
i00
17-7-885
H-P-KUMAR
SWELL -CONSOLIDATION TEST RESULTS
Fig. 4
ERRF
CONSOLIDATION - SWELL
CONSOLIDATION - SWELL
—3
SAMPLE OF: Sandy Clay
FROM: Boring 2 2.5'
WC = 6.8 %, DD = 118 pcf
1.0'
APPLIED PRESSURE - KSF
EXPANSION UNDER CONSTANT
PRESSURE UPON WETTING
10
100
SAMPLE OF: Sandy Clay
FROM: Boring 2 IP 10'
WC = 5.4 %, DD = 120 pcf
Into* 411 .n 4o .ppry eny to Vie
ee.n01$ I..1ed iM WW1 rap..l
Omar not be rapraluc.d, ..e.pt in
I l..11hou1 the .Allen appro..! .1
%w1.pr .ed Nxcooln, Y.c S.all
eccvfw4ln Iwlrrpq ynlerm.d u.
wepee..4h SSty G-55ec
EXPANSION UNDER CONSTANT
PRESSURE UPON WETTING
1.0 APPLIED PRESSURE - KSF 10
I00
17-7-885
H-P45KUMAR
SWELL -CONSOLIDATION TEST RESULTS
Fig. 5
TABLE 1
SUMMARY OF LABORATORY TEST RESULTS
Project No. 17-7-885
SAMPLE LOCATION NATURAL NATURAL — GRADATION ATTERBERG LIMITS
PERCENT UNCONFINED
BORING DEPTH MOISTURE DRY GRAVEL SAND PASSING LIQUID PLASTIC COMPRESSIVE
CONTENT DENSITY (%) (%) NO. 200 LIMIT INDEX STRENGTH
(ft) (%) (pcf) i SIEVE (%) (%) (pg� jl
1
2
21/2 6.4
5
15
212
7.6
9.3
6.8
109
112
119
118
L
82
SOIL TYPE
Sandy Silty Clay
Sandy Silty Clay
Sandy Clay
Sandy Clay
10
5.4
120
Sandy Clay