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HEPWORTH-PAWLAK GEOTECHNICAL
SUBSOIL STUDY
Hepworth-Pawlak Geotechnical, Inc.
5020 County Road 154
Glenwood Springs, Colorado 81601
Phone: 970-945-7988
Fax: 970-945-8454
Email: hpgeo@hpgeotech.com
FOR FOUNDATION DESIGN
PROPOSED RESIDENCE
LOT 86, IRONBRIDGE, PHASE 2
RIVER BANK LANE
GARFIELD COUNTY, COLORADO
JOB NO. 115 037A
FEBRUARY 27, 2015
PREPARED FOR:
JAMES AND CONNIE MEINE
2903 SOUTH OAK WAY
LAKEWOOD, COLORADO 80227
jamesmeine@msn.com
comeine@g mail.com
TABLE OF CONTENTS
PURPOSE AND SCOPE OF STUDY ............................................................................ - 1 -
PROPOSED CONSTRUCTION ..................................................................................... - 1 -
SITE CONDITIONS ............................................................................................................................................ - 2 -
SUBSIDENCE POTENTIAL ..••..•••.•••••.•...........................................•...•.•.•.•.................. - 2 -
FIELD EXPLORATION ................................................................................................. - 3 -
SUBSURFACE CONDITIONS ...................................................................................... - 3 -
FOUNDATION BEARING CONDITIONS ................................................................... - 4 -
DESIGN RECOMMENDATJONS ................................................................................. - 5 -
FOUNDATIONS ......................................................................................................... - 5 -
FOUNDATION AND RETAINING WALLS ............................................................ -6-
FLOOR SLABS .......................................................................................................... -7 -
UNDERDRAIN SYSTEM ...................................... ~ .. ~ ...................................................................... - 8 -
SURF ACE DRAINAGE ............................................................................................. - 8 -
LIMITATIONS ............................................................................................................................. -9 -
FIGURE 1 -LOCATIONS OF EXPLORATORY BORINGS
FIGURE 2 -LOGS OF EXPLORATORY BORINGS
FIGURE 3 -LEGEND AND NOTES
FIGURES 4 and 5 -SWELL-CONSOLIDATION TEST RESULTS
FIGURE 6 -GRADATION TEST RESULTS
TABLE 1 -SUMMARY OF LABO RA TORY TEST RES U LTS
Job No. I IS 037A
PURPOSE AND SCOPE OF STUDY
This report presents the results of a subsoil study for a proposed residence to be located
on Lot 86, Ironbridge, Phase 2, River Bank Lane, Garfield County, Colorado. The project
site is shown on Figure 1. The purpose of the study was to develop recommendations for
the foundation design. The study was conducted in accordance with our agreement for
geotechnical engineering setvices to James and Connie Meine dated February 3, 2015 .
Hepworth-Pawlak Geotechnical previously conducted geotechnical engineering studies
for the subdivision development and presented their findings in reports dated October 29,
1997 and February 12, 1998 , Job No. 197 327.
A field exploration program consisting of exploratory borings was conducted to obtain
infonnation on the subsurface conditions. Samples of the subsoils and bedrock obtained
during the field exploration were tested in the laboratory to detennine their expansion or
compressibility potential, classification 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 subsurface conditions encountered.
PROPOSED CONSTRUCTION
The proposed construction on the lot was preliminary at the time of our study. In
general, the residence will be mainly a 2-story structure above a walkout basement level
with an attached garage at the main level and located as shown on Figure 1. The garage
and basement floors will 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 residential type 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.
Job No. 115 037A
-2-
SITE CONDITIONS
The lot is located at the t ransition of two relatively flat terraces about 150 feet west and
about 15 to 25 feet higher than the Roaring Fork River. The ground surface slopes gently
down to the northeast on the terraces and moderate on the intervening slope between the
terraces with about 12 feet o f elevation difference across the building footprint. The lot is
vegetated with natural grass and weeds. Scattered cobbles and boulders are visible on the
ground surfa ce of the upper terrace which appears to contain fill material possi bly from
the subdivision development. A small flowing stream of water apparently from a buried
pipe is located roughly along the north property line at the lower terrace level. It is
suspected that the pipe is the outlet of a subdrain install ed for intercepti ng groundwater
within or above River Bank Lane.
SUBSIDENCE POTENTIAL
Bedrock of the Pennsylvanian age Eagle Valley Evaporite underlies the lronbridge
Development. These rocks are a sequence of gypsiferous shale, fine-grained sandstone
and siltstone with some massive beds of gypsum and limestone. There is a possibility
that massive gypsum deposits associated with the Eagle Valley Evapori te underlie
portions of the lot. Dissolution of the gypsum under certain conditions can cause
s inkholes to develop and can produce areas of localized su bs idence. During pr evious
studies for the subdivision development, several sinkholes were observed scattered
throughout the Ironbridge Development. These sinkholes appear similar to others
a ssociated with the Eagle Vall ey Evaporite in areas of the Roaring Fork River valley.
The closest mapped sinkhole is located about 1,200 feet southwest of Lot 86 in the t61h
fairway. Another sinkhole is localed roughly below the intersection of River Bank Lane
and River Bend Way about 1,200 feet to the north. The subsidence evaluation for
r emediation of this sinkhole during P hase 2 development was presented in our report
dated July 7, 2006, Job No. 105 115-4. Both of these sinkholes appear to be associated
with the underlying bedrock condition.
Job No. 115 037A
-3-
Sinkholes related to the underlying fonnation rock were not observed in the immediate
area of the subject lot. No evidence of cavities was encountered in the subsurface
materials; however, the exploratory borings were relatively shallow, for foundation
design only. Based on our present knowledge of the subsurface conditions at the site, it
cannot be said for certain that sinkholes will not develop. The risk of future ground
subsidence on Lot 86 throughout the service life of the proposed residence, in our
opinion, is low; however, the owner should be made aware of the potential for sinkhole
development. If further investigation of possible cavities in the bedrock below the site is
desired, we should be contacted.
FIELD EXPLORATION
The field exploration for the project was conducted on February 9 and 10, 2015. Five
exploratory borings were drilled at the locations shown on Figure I to evaluate the
subsurface conditions. The borings were advanced with 4-inch diameter continuous flight
augers. Borings I and 2, on the upper terrace, were drilled with a truck mounted CME
45B drill rig and a track mounted CME-45 drill rig was used at Borings 3, 4 and 5 due to
recent snow melt and soft ground surface conditions. The borings were logged by a
representative of Hepworth-Pawlak Geotechnical, Inc.
Samples of the subsurface materials were taken with 1¥s inch and 2 inch I.D. spoon
samplers. The samplers were 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.
The subsoils consist of about Vi to 2 feet of topsoil or man-placed fill and 4Yl to 8Yi feet
Job No . 115 037A
-4-
of stratified clay and sand soils overlying dense, silty sandy gravel and cobbles with
boulders down to the maximum explored depth of 5Yi to 12 feet in Borings 1, 3 and 4. At
Borings 2 and 5, claystone/siltstone bedrock was encountered down to t he drilled depths
of 12 to 20 feet. The clay soil was stiff to very sti ff on the upper terrace, and soft to
medium stiff on the lower terrace. The sand soils were generally medium dense and
contains scattered gravel. Dri lli ng with auger equipment was difficu lt in the coarse
granular soils due to the cobbles and small boulders and in the cemented bedrock at
Boring 5, and drilling refusal was encountered in the deposits.
Laboratory testing performed on samples obtained fr om the borings included natural
moisture content and density and gradation analyses. Results of swell-consolidation
testing performed on samples of the clay soi ls, shown on Figure 4, indicate low
compressibility under existing low moisture conditions and relatively light loading, a
minor coll apse potential (settlement under a constant load) after wetting and moderate
compressibility under increased load ing after wett ing. The sample of weathered bedrock
showed low to moderate compressibi lity under loading and a minor expansion potential
when wetted.
Free water was encountered at a depth of about 4Yi and 5 feet on the lower terrace and at
abou t 9 and 12 feet on the upper terrace. The upper soils were generally very moist to
wet with depth. The upper clay and sand soils at Borings l, 2 and 3 were slightly moist to
moist.
FOUNDATION BEARING CONDITIONS
The soils encountered at relatively shallow depths across the building site are variable in
type, moisture content and cons istency/density. The clay and sand soils are generally
compressible under light loading with low bearing capacity. The dense, silty sandy
gravel and cobbles soils and siltstone/claystone bedrock have moderate bearing capacity
and are suitable for support of shallow spread footings with low settlement potential. The
upper clay and sand soils are compressible under loading and there will be a risk of
differential settlement especially with respect to gravel or bedrock bearing areas.
Extending the bearing level down to the dense gravel or bedrock, or re-establishing
Job No. 115 037A
-5-
design bearing level with compacted structural fill will reduce the settlement potential and
risk of building distress. Due to the shallow groundwater in the lower part the building
envelope, we recommend that the lower floor in this area be slab-on-grade to avoid a
potentially wet crawlspace. The suitability of the natural soils exposed in the building
excavation should be further evaluated at the time of construction.
DESIGN RECOMMENDATIONS
FOUNDATIONS
Considering the subsurface conditions encountered in the exploratory borings and the
nature of the proposed construction, we recommend the building be founded with spread
footings bearing on the natural gravel soils, bedrock or compacted structural fill.
The design and construction criteria presented below should be observed for a spread
footing foundation system.
I) Footings placed on the undisturbed natural gravel soils, .bedrock or
compacted structural fill should be designed for an allowable bearing
pressure of2,500 psf. Based on experience, we expect settlement of
footings designed and constructed as discussed in this section will be up to
about 1 inch.
2) The footings should have a minimum width of 16 inches for continuous
walls and 2 feet for isolated pads.
3) Exterior footings and footings beneath unheated areas should be provided
with adequate soil cover above their bearing elevation for frost protection.
Placement of foundations at least 36 inches below exterior grade is
typically used in this area.
4) Continuous foundation walls should be reinforced top and bottom to span
local anomalies such as by assuming an unsupported length of at least 12
feet. Foundation walls acting as retaining structures should also be
designed to resist lateral earth pressures as discussed in the 11 Foundation
and Retaining Walls" section of this report.
Job No. 115 037A
5) The existing fill, topsoil , clay soil s and loose or disturbed soils should be
removed and the footing bearing level extended down to the natural
granular soils or bedrock. The sand soils should be evaluated for bearing
or removal for structural fill placement to support footings. The exposed
soils in foot ing areas should be moisture adjusted to near optimum and
compacted prior to constructing footings or placing fill. Structural fill
used to re-establish design bearing level sho uld consist of a granular soil
similar to the on-site sand and gravel soils and be compacted to at least
98% of standard Proctor density at near optimum moisture content.
Excavation dewatering (in addition to the underdrain around the basement
level as described below) in the lower terrace area will probably be
required until the structural fill has been p laced and compacted.
6) A representative of the geotechnical engineer should observe all foot ing
excavations prior to concrete placement to evaluate bearing conditions.
FOUNDATION AND RETAINING WALLS
Foundat ion 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 at least 50 pcf
for backfill consist ing of the on-site granular soils. Cantilevered retaining structures
which are separate from the residence and can be expected to defl ect sufficiently to
mobi lize 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 at least 40 pcf for
backfill con sisting of the on-site granular soils. Backfill should not cont ain organics or
rocks la rger than about 6 inches.
All foundation a nd retaining structures should be designed for appropriate hydrostatic an d
surcharge pressures such as adjacent footings, traffic, construct ion 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
s loping backfill surface will increase the lateral pressure imposed on a foundation wall or
Job No. 11 5 037A
- 7 -
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
and walkway 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.
The lateral resistance of foundation or 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 of0.45. Passive pressure of compacted
backfill against the sides of the footings can be calculated using an equivalent fluid unit
weight of 400 pcf for dry conditions. 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 consist of granular soil and be compacted to at least
95 % of the maximum standard Proctor density at near optimum moisture content.
FLOOR SLABS
The natural on-site granular soils and possibly the upper drier clay soils are suitable to
support tightly loaded slab-on-grade construction. To reduce the effects of some
differential movement, floor slabs should be separated from all bearing walls and
columns with expansion joints which allow unrestrained vertical movement. Floor slab
control joints should be used to reduce damage due to shrinkage cracking. The
requirements for 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 beneath basement level slabs to facilitate drainage. This
Job No . 115 037A
material should consist of minus 2 inch aggregate with at least 50% retained on the No. 4
sieve and less than 2% passing the No. 200 sieve.
All fill materials for support of floor slabs should be compacted to at least 95% of
maximum standard Proctor density at near optimum moisture content. Required fill can
consist of the on-site granular soils devoid of vegetation, topsoil and oversized rock.
Structural fill used to elevate grade on the lower terrace level should be limited to a depth
of about 5 feet below the building area.
UNDERDRAIN SYSTEM
Free water was encountered at relatively shallow depth and it has been our experience in
the area that the groundwater level can rise and local perched groundwater can develop
during times of heavy precipitation or seasonal runoff. Frozen ground during spring
runoff can create a perched condition. We recommend below-grade construction, such as
retaining walls, crawlspace and basement areas, be protected from wetting and
hyd rostatic pressure buildu p by an underdrain system.
The drains should consist of drainpipe placed in the bottom of the wall backfi ll
surrounded above the invert level with free-draining granular material. The drain should
be placed at each level of excavation and at least I foot below lowest adjacent finish
grade and sloped at a minimum I % to a suitable gravity outlet above the 100 year flood
level. Free-draining granular material used in the underdrain system should contain less
t han 2 % passing the No. 200 sieve, less than 50% pass ing the No. 4 sieve and have a
maximum size of 2 inches. The drain gravel backfill should be at least I Yi feet deep .
SURF ACE DRAINAGE
The following drainage precautions should be observed during construction and
maintained at all times after the residence has been completed:
1) Inundation of the foundation excavations and underslab areas should be
avoided during construction.
Job No . 11 5 037A
-9-
2) Exterior backfill should be adjusted to near optimum moisture and
compacted to at least 95% of the maximum standard Proctor density in
pavement and slab areas and to at least 90% of the maximum standard
Proctor density in landscape areas.
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.
Free-draining wall backfill should be capped with about 2 feet of the on-
site finer grained soils to reduce surface water infiltration.
4) Roof downspouts and drains should discharge well beyond the limits of all
backfill.
5) Landscaping which requires regular heavy irrigation, such as sod, and
sprinkler heads should be located at least 5 feet from foundation walls.
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 l, 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 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 different from those described in this report, we
should be notified so that 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
Job No. 115 037A
-10-
project evolves, we should provide continued consultation and field services during
construction to review and monitor rhe implementation of our recommendat ions, and to
verify that the recommenda tions have been appropriately interpreted. Significant design
changes may require additional analysis or modifications to the recommendations
presented herein. We r ecommend on-site observation of excavations and fo undation
bearing strata and testing of structural fill by a representative of the geotechnical
engineer.
Respectfully Submitted,
HE PWORTH -PAWLAK GEOTECHNICAL, INC.
Steven L. Pawlak, P.E.
Reviewed by:
Dan iel E. Hardin, P.E.
SLP/ksw
Job No. U S 037A
ROARING FORK RIVER -~~~----------------
---
APPROXIMATE SCALE
1· = 30'
.-_.::-;;..----r-------..:..::-::.-. ___ -===-=------------------------
--
APPROX IMATE OUTLET
I OF DRAIN PIPE
I t I
BORINGS e
--------
BOA~
PROPOSED
RESIDENCE
--------s~-----------------------
-
L
/
115 037A ~
HEPWORTH-PAWLAK GEOTECHN1CAL
__ --5940 __ , ----r--__
BORING 3 I
\ I
J
BORING 1 •
RIVER BANK LANE
_J
LOCATION OF EXPLORATORY BORINGS
/
Figure 1
iii
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BORING 1
ELEV. c::i 5944•
5945
BORfNG2
ELEV.= 5942'
BORING3
ELEV.= 594 1'
ASSUMED MAIN FLOOR LEVEL
23/1 2
5940 wc .. a.a
D0=106
75/12
9/12
8/12 9/12
WC=21 .1 WC=12.0
5935 DD=96 00=94
·200=32
50/6 25/6 ,10/0
WC=t0.1 +4=20
5930 8 00=116 ·200=16
--7 ---
5012 0
~ ---5925
50/3
5920
5915
BORING4
ELEV.= 5933'
BORINGS
ELEV.= 5932'
5945
5940
5935
ASSUMED BASEMENT FLOOR LEVEL
5/12
5930
4/12
WC=18.1 2/12
·200 =91 7 -o-=---5925
50/4
37/12
wc ~1.3
DD =121
5920
5915
Note: Explanation of symbols is shown on Figu re 3.
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115 037A ~ LOGS OF EXPLORATORY BORINGS Figure 2
HEPWORTH-PAWLAK GEOTECHNICAL
LEGEND :
FILL; mixed sand and clay, scattered gravel , loose, moist, mixed brown .
TOPSOIL; organic sandy silt and clay, moist. dark brown .
CLA.Y (CL); silty, sandy, stiff and slightly moist to wet with depth at Borings 4 and 5, brown, low plasticity.
SAND AND CLA.Y (SM-CL); stratified, scattered gravel, loose/stiff, moist to very moist and wet with depth at
Borings 3 and 4, brown .
GRAVEL AND COBBLES (GM); silty , sandy, possible boulders, dense, grey, rounded rock .
SILTSTONE/CLA.YSTONE BEDROCK; weathered and medium hard to hard with depth, moist to slightly moist with
depth, grey. Eagle Valley Evaporite.
Relatively undisturbed drive sample ; 2-inch 1.0 . California liner sample.
Drive sample; standard penetration test (SPT), 1 3/8 inch l.D. split spoon sample , ASTM D-1586 .
23112 Drive sample blow count: indicates that 23 blows of a 140 pound hammer falling 30 inches were
required to drive the California or SPT sampler 12 inches.
0,7
[]
T
NOTES :
Free water level in boring and number of days following drilling measurement was taken .
Depth at which boring had caved when checked on February 17, 2015 .
Indicates slotted PVC pipe installed in bo ri ng to depth shown .
Practical drilling refusal.
1. Exploratory borings were drilled on February 9 and 10, 2015 with 4-inch diameter continuous flight power auger.
2. Locations of exploratory borings were measured approximately by pacing from features shown on the site plan
provided.
3. Elevations of exploratory borings were obtained by interpolation between contours shown on the site plan provided
and their relative elevation checked by instrument level.
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 transitions may be gradual .
6. Water level readings shown on the logs were made at the time and under the conditions Indicated . Fluctuations in
water level may occur with time.
7. Laboratory Testing Results :
WC = Water Content (%)
OD -Dry Density (pcf)
115 037A
+4 =Percent retained on the No . 4 sieve
-200 = Percent passing No. 200 sieve
LEGEND AND NOTES Figure 3
0
r-r--Moisture Conte nt = a.a percent --...... ·o Dry Den sity = 106 p cf 1
I~
Samp le of: Sandy Clay
Fro m: Bori ng 1 at 2 ~ Feet
2 \' ~ \ '-.,
3 "' ",
\ -1'-' Compres sion ' upon
'#. 4 wetting
c \ 0
'(jj
(/) 5 ~ a. ' E 1 l
0 \ u 6
'
7 \
' n
a
0 .1 1.0 10 100
APPLIED PRESSURE -ksf
Moisture Con tent = 21.1 percen t
Dry Densi ty = 96 pcf
Sa mple of: Sandy Clay
From: Borin g 2 at 5 Fe et
0 --,.....,._ "()_ '#. ,,
1 ---c .Q "-. <::: --Compress ion (/) -.. m "" :-r--,_ upon
I a. 2 wetti ng
E ~ 0 u "h '
3
0 .1 l.O 10 100
APPLIED PRESSURE -ksf
115 037A ~ SWELL-CONSOLIDATION TEST RESULTS Figure 4
HEPWORTH-PAWLAK GEOTECHNICAL
Moisture Content = 7.3 percent
Dry Density = 121 pcf
Sample of: Weathered Siltstone/Claystone
From : Boring 5 at 9 Feet
0 ----~ ~ ~ c: 1 ....... ~ I~ 0 ·u; ~1'1 \""' c: ro c.
r-..... in 2
I ~ ) c: ~ .2 en en 3 ~ I\.
c. Expansion '\ ~ upon ~~ u wetting 4
0 .1 1.0 10 100
APPLIED PRESSURE -ks!
115 037A ~ SWELL-CONSOLIDATION TEST RESULTS Figure 5
HEPWORTH-PAWLAK GEOTECHNICAL
0 w z
<(
I-w a:::
I-z w u a::: w
Cl.
HYDROMETER ANALYSIS I SIEVE ANALY SIS
CLEAR SQUARE OPENI NGS I I 7 HR TIME READINGS I U.S . STANDARD SERIES I O~~tl~.15MIN.60MINJ9MIN .4MIN.1MIN . #200 #100 #50 #30 #16 #8 #4 318" 314' 1 112· 3• 5"6" 0 · 100
10
20
30
40
50
60
70
80
90
100
.001
.
.002 .005 .009 019 .037 .074 .150
. .
: .
76.2 152 203
127
.300 .600 l.18 2 36 4.75 95 19.0 37,5
125
DIAMETER OF PARTICLES IN MIWMETERS
FINI;
SAND I r.AAi.tL I I MEDIUM I COARSE. FNE I COARSE COElat.ES
GRAVEL 20 % SAND 64 % SILT AND CLAY 16 %
LIQU ID LIMIT % PLASTICITY INDEX %
SAMPLE OF: Silty Gravelly Sand FROM: Boring 3 at 9 Feet
90
80
70
60
50
40
30
20
10
0
(,!) z
1ii
Vl
<(
Cl.
I-z w u a::: w
Cl.
115 037A ~ GRADATION TEST RESULTS Figure 6
HEl'WO~P.11.WLAK GEOTEC:liNICAI.
HEPWORTH-PAWLAK GEOTECHNICAL, INC.
TABLE I Job No. 115 037A
SUMMARY OF LABORATORY TEST RESULTS
SAMPLE LOCATION NATURAL NATURAL GRADATION
PERCENT
ATTERBERG LIMITS UNCONFINED
MOISTIJRE DRY GRAVEL SAND PASSING LIQUID PLASTIC COMPRESSIVE SOIL OR BORING DEPTH CONTENT DENSITY N0.200 LIMIT INDEX STRENGTH BEDROCK lYPE (%) (%)
SIEVE
((r) (%) (nd'I (%) (%) IPSA
1 2 1h 8.8 106 Sandy Clay
2 5 21.1 96 Sandy Clay
116 Weathered 10 10 .1 Siltstone/Clavstone
3 4 12.0 94 32 Silty Clayey Sand
9 20 64 16 Silty Gravelly Sand
4 4 18 .1 91 Slightly Sandy Silty Clay
9 7.3 121 Weathered 5 Siltstone/Clay stone