HomeMy WebLinkAboutSoils Report 11.21.2019K±A
lKumar & Associates, Inc.°
Geotechnical and Materials Engineers
and Environmental Scientists
5020 County Road 154
Glenwood Springs, CO 81601
phone: (970) 945-7988
fax: (970) 945-8454
email: kaglenwood@kumarusa.com
An Employee Owned Company wwwkumarusa.com
Office Locations: Denver (HQ), Parker, Colorado Springs, Fort Collins, Glenwood Springs, and Summit County, Colorado
GEOTECHNICAL STUDY
PROPOSED RICHARDSON MINOR SUBDIVISION
3135 COUNTY ROAD 134
GARFIELD COUNTY, COLORADO
PROJECT NO. 19-7-670
NOVEMBER 21, 2019
PREPARED FOR:
TYE RICHARDSON
P. O. BOX 181
GLENWOOD SPRINGS, COLORADO 81602
D a ry_ltve55 (@ gm ail. corn
TABLE OF CONTENTS
PURPOSE AND SCOPE OF STUDY - 1 -
PROPOSED DEVELOPMENT 1
SITE CONDITIONS. - 2..
FIELD EXPLORATION .. 2 -
SUBSURFACE CONDITIONS - 2 -
GEOLOGIC SETTING - 3 -
GEOLOGIC ASSESSMENT - 3 -
DEBRIS FLOW/DEBRIS FLOOD - 3 -
POTENTIALLY UNSTABLE SLOPES - 5 -
COLLAPSIBLE/EXPANSIVE SOILS - 5 -
EARTHQUAKE CONSIDERATIONS 5 -
FOUNDATION BEARING CONDITIONS 6 -
DESIGN RECOMMENDATIONS .. - 6 -
ONSITE WASTEWATER TREATMENT SYSTEMS (OWTS) - 6 -
FOUNDATIONS -6-
FLOOR SLABS - 7
UNDERDRAIN SYSTEM _ S -
SITE GRADING - g -
SURFACE DRAINAGE - 8 -
LIMITATIONS - 9 -
REFERENCES -1p-
FIGURE 1 - LOCATION OF EXPLORATORY PITS
FIGURE 2 - LOGS OF EXPLORATORY PITS
FIGURE 3 - SWELL -CONSOLIDATION TEST RESULTS
FIGURE 4 - GRADATION TEST RESULTS
FIGURE 5 - REGIONAL GEOLOGY MAP
TABLE 1 - SUMMARY OF LABORATORY TEST RESULTS
Kumar & Associates, Inc. Project No. 19-7-670
PURPOSE AND SCOPE OF STUDY
This report presents the results ofa geologic hazards review and geotechnical study for the
proposed Richardson Minor Subdivision located at 3155 County Road 134, Garfield County,
Colorado. The project site is shown on Figure 1. The purpose of the study was to evaluate the
geologic and subsurface conditions, their potential impacts on the project and as response to the
review comments by the Colorado Geological Survey, reported dated October 17, 2019. The
study was conducted in accordance with our agreement for geotechnical engineering services to
Tye Richardson, dated November 1, 2019.
A field exploration program consisting ofa reconnaissance and exploratory pits was conducted
to obtain information on the site and subsurface conditions. Samples of the subsoils 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 project
planning and foundation types, depths and allowable pressures for the proposed building
foundation. This report summarizes the data obtained during this study and presents our
conclusions and recommendations based on the proposed development and subsurface conditions
encountered.
PROPOSED DEVELOPMENT
The proposed development consists of a two -lot subdivision as shown on Figure 1, including a
single family home on Lot 2. The proposed Lot 1 consists of the existing residence development
on the property. A private driveway will access the building site on Lot 2. We assume the
residence on Lot 2 will be typical of the area and be one to two stories with or without a garage.
Ground floors could be slab -on -grade or structural over crawlspace. Grading for the structure
will be relatively minor with cut depths between about.2 to 5 feet. The development will be
serviced with a well and septic disposal system.
If development plans change significantly from those described, we should be notified to re-
evaluate the recommendations presented in this report.
Kumar & Associates, Inc. ® Project No. 19-7-670
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SITE CONDITIONS
The proposed subdivision consists of about 41.38 acres located in the W1/2 SW1/4 SW1/4 of
Section 14, T6S, R9OW of the 6th Prime Meridien. The proposed residence on Lot 2 will be
located approximately as shown on Figure 1. The existing development in the area of the
proposed Lot 1 will remain. The terrain is the transition between valley bottom and valley side
with gentle to very steep slopes generally down to the southeast. The elevation ranges from
about 6,500 to 6,550 feet in the proposed building area. There is currently a riding arena in the
area of the proposed residence on Lot 2. Vegetation consists of native grass and weeds in the
proposed building area on Lot 2 and in the area around the existing development on the proposed
Lot 1, and thick scrub oak with scattered conifers on the steep slopes to the west.
FIELD EXPLORATION
The field exploration for the project was conducted on November 4, 2019. Three exploratory
pits were excavated at the locations shown on Figure 1 to evaluate the subsurface conditions.
The pits were dug with a Deere 50D rubber -tracked mini -excavator. The pits were logged by a
representative of Kumar & Associates, Inc.
Samples of the subsoils were taken with relatively undisturbed and disturbed sampling methods.
Depths at which the samples were taken are shown on the Logs of Exploratory Pits, 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 2V2 feet of topsoil overlying very silty clayey sand with scattered gravel
in Pit 2. About 1'/2 feet of previously placed fill material consisting of organic sand and clay
overlying about 1 foot of native silty sandy gravel was encountered above the very silty clayey
sand with scattered gravel in Pit 1.
Laboratory testing performed on samples obtained from the pits included natural moisture
content and density and gradation analyses. Results of swell -consolidation testing performed on
a relatively undisturbed sample of the very silty clayey sand, presented on Figure 3,
Kumar & Associates, Inc. 0 Project No. 19-7-670
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indicate moderate compressibility under conditions of loading and wetting and a minor hydro. -
compression potential when wetted under a constant 1,000 psf surcharge. Results of gradation
analyses performed on a bulk sample of very silty clayey sand with scattered gravel are shown
on Figure 4. The laboratory testing is summarized in Table 1.
No free water was encountered in the pits at the time of excavation and the subsoils were slightly
moist.
GEOLOGIC SETTING
The project site lies just south of the axis of the Grand Hogback monocline along the southern
margin of the White River uplift. Formation rock in the project area consists of the Cretaceous
age Williams Fork Formation of the Mesaverde Group. The Williams Fork Formation is
generally a yellowish grey sandstone with interbedded siltstone, shale, and coal seams. The
bedding dip of the Williams Fork Formation in the general vicinity of the project site is about
50 degrees down to the southwest. Surficial deposits at the project site are alluvium and
colluvium deposited by and along Delsas and Canyon Creeks consisting of interbedded silty
clayey sand and gravel.
GEOLOGIC ASSESSMENT
Geologic conditions that would make the proposed development infeasible were not identified in
the proposed development areas.
DEBRIS FLOW/DEBRIS FLOOD
The basin (Delsas Creek) to the west of the proposed development area covers about 554 acres.
The basin has a maximum elevation of about 8,200 feet and the fan head at the mouth of the
basin lies at an elevation of about 6,520 feet. The average slope of the basin is 20 percent and
the basin has a Milton number of 0.34. The Milton number is an index of basin roughness. It is
the basin relief divided by the square root of the basin area. The basin alluvial fan covers about
3.4 acres and has an average slope of about 4 percent. The ratio of fan area to basin area is about
0.6 percent. The basin can be characterized as a moderate sized basin with low slope and low
roughness with a very small, gently sloping fan at its mouth. Proposed Lot 1 lies within this fan
area.
Project No. 19.7.670
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The debris flow and flood potential at the project site has been evaluated based on the geologic
setting and geomorphic analysis of the drainage basin and alluvial fan in the west part of the
project area. This analysis indicates that the alluvial fan is geologically young (formed in post -
glacial times, during the past 15,000 years) and has the potential to produce debris floods in the
future, but it is unlikely that the basin will produce debris flows.
To our knowledge, a major debris flood has not occurred on the fan during the last 50 years.
However, debris floods have occurred in western Colorado on similar fans during this time.
These debris floods were triggered by unusually intense thunderstorms or unusually rapidly
melting of a heavy snowpack. Thunderstorm triggered debris floods are the most likely at the
project site. The drainage basin at the project site has a Milton number of 0.34 and a small
alluvial fan in comparison to the basin area. Studies of alluvial fans where fan stratigraphy is
available indicate that drainage basins with Milton numbers similar to the project site only
produce debris floods or, if they produce debris flows, the statistical recurrence probability of
debris flow on their fans is long, greater than about 2,000 to 4,000 years (Coe and Others, 2003).
Without long term observations it is not possible to assign statistical recurrence probabilities to
future debris floods at the project site with a high level of confidence. A major debris flood at
the project site may have a statistical recurrence probability in the range of 50 to 500 years, or
possibly longer. A major debris flood at the project site has the potential to damage the existing
buildings located on the northeastern part of the fan on Lot I, however, the proposed building
area on Lot 2 is at approximately the same elevation or higher than the mouth of the basin. It is
unlikely that even in the event of a major debris flood, the proposed building area on Lot 2
would be significantly impacted. With proper grading and drainage around the proposed
building on Lot 2 as presented below in "Design Recommendations", in our opinion, no debris
flow/debris flood mitigation is warranted.
There is a small, very steep basin to the east of the proposed development area with an
established fan to the east of South Canyon Creek. Small debris flows and debris floods could
occur on this fan in the future. No development is proposed on this fan and the South Canyon
Creek channel will act as a catchment area for debris flow/floods if they were to occur. It is
unlikely that a debris flow/flood on this fan would reach the proposed development area on the
proposed Lot 2 and in our opinion, no mitigation is warranted at this time for the proposed
development.
Kumar & Associates, Inc. a Project No. 19.7.670
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POTENTIALLY UNSTABLE SLOPES
Slopes greater than 30 percent are not present in the proposed development areas. The natural
steep slope to the west of the proposed building area on Lot 2 is not proposed to be modified and
appears stable under current conditions and should not pose a risk to the proposed development
with proper grading and construction practices as presented below in "Design
Recommendations".
COLLAPSIBLE/EXPANSIVE SOILS
Hydrocompressive soils are present at the site. Mitigation options of compressible soils are
presented below in the "Design Recommendations" sections of this report.
EARTHQUAKE CONSIDERATIONS
Historic earthquakes within 150 miles of the project site have typically been moderately strong
with magnitudes less than 5.5 and maximum Modified Mercalli Intensities less than VI
(Widmann and Others, 1998). The largest historic earthquake in the project region occurred in
1882. It was located in the northern Front Range and had an estimated magnitude of about M6.4
± 0.2 and a maximum intensity of VII. Historic ground shaking at the project site associated
with the 1882 earthquake and the other larger historic earthquakes in the region does not appear
to have exceeded Modified Mercalli Intensity VI (Kirkham and Rogers, 2000). Modified
Mercalli Intensity VI ground shaking should be expected during a reasonable exposure time for
the residences, but the probability of stronger ground shaking is low. Intensity VI ground
shaking is felt by most people and causes general alarm, but results in negligible damage to
structures of good design and construction.
For firrn rock sites with shear wave velocities of 2,500 fps in the upper 100 feet, the U. S.
Geological Survey 2014 National Seismic Hazard Maps indicates that a peak ground acceleration
of 0.06g has a 10% exceedance probability for a 50-year exposure time and a peak ground
acceleration of 0.20g has a 2% exceedance probability for a 50-year exposure time at the project
site (Peterson and Others, 2014). This corresponds to a statistical recurrence time of about 50
years and 2,500 years, respectively. Based on our review, a Seismic Soil Class D as described in
the 2015 International Building Code can be assumed for the project site.
Kumar & Associates, Inc. Project No. 19-7-670
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FOUNDATION BEARING CONDITIONS
The subsoils at the site possess low bearing capacity and, in general, moderate settlement .
potential, especially when wetted. Lightly loaded spread footings bearing on the natural soils
should be feasible for foundation support of the residence with some risk of settlement. The risk
of settlement is primarily if the bearing soils were to become wetted and precautions should be
taken to prevent wetting. A lower risk of foundation settlement would be to remove a depth of
the on -site soils (typically 3 feet) and replace in a moisture controlled and compacted condition.
Provided below are recommendations for spread footings bearing on the natural soils. If
recommendations for structural fill below the footings are desired, we should be contacted.
DESIGN RECOMMENDATIONS
ONSITE WASTEWATER TREATMENT SYSTEMS (OWTS)
Conventional OWTS systems appear feasible for the proposed development at this site. We are
currently designing the system for the proposed residence on the proposed Lot 2.
FOUNDATIONS
Considering the subsurface conditions encountered in the exploratory pits and the nature of the
proposed construction, the proposed building on Lot 2 can be founded with spread footings
bearing on the natural soils with a risk of settlement. A lower risk of foundation settlement
would be to bear the footings on three feet of compacted structural fill.
The design and construction criteria presented below should be observed for a spread footing
foundation system.
1) Footings placed on the undisturbed natural soils should be designed for an
allowable bearing pressure of 1,200 psf. Based on experience, we expect
settlement of footings designed and constructed as discussed in this section will
be up to about 1 inch or less. There could be some additional settlement if the
bearing soils were to become wetted. The magnitude of the additional settlement
would depend on the depth and extent of the wetting but may be up to about
1 inch.
Kumar & Associates, Inc. ® Project No. 19-7-670
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2) The footings should have a minimum width of 20 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 heavily reinforced top and bottom to span
local anomalies such as by assuming an unsupported length of at least 14 feet.
Foundation walls acting as retaining structures should also be designed to resist a
lateral earth pressure corresponding to an equivalent fluid unit weight of at least
55 pcf.
5) All existing fill, topsoil and any loose or disturbed soils should be removed and
the footing bearing level extended down to the relatively dense natural soils. The
exposed soils in footing area should then be moistened and compacted.
6) A representative of the geotechnical engineer should observe all footing
excavations prior to concrete placement to evaluate bearing conditions.
FLOOR SLABS
The natural on -site soils, exclusive of topsoil, are suitable to support lightly 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 relatively
well graded sand and gravel should be placed beneath slabs -on -grade for support. This material
should consist of minus 2-inch aggregate with at least 50% retained on the No. 4 sieve and less
than 12% 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 a moisture content near optimum. Required fill should consist of a
relatively well graded sand and gravel material such as CDOT Class 6 road base.
Kumar & Associates, Inc. 0 Project No. 19-7-670
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UNDERDRAIN SYSTEM
Ali underdrain around shallow crawlspacc areas (less than 4 feet deep) should not be needed with
adequate compaction of foundation wall backfill and positive surface slope away from
foundation walls.
SITE GRADING
The risk of construction -induced slope instability at the site appears low provided the building is
located below the steep slope as planned and cut and fill depths are limited. We assume that cut
depths will not exceed up to about 6 feet. Fills should be limited to about 8 to 10 feet deep.
Embankment fills should be compacted to at least 95% of the maximum standard Proctor density
near optimum moisture content. Prior to fill placement, the subgrade should be carefully
prepared by removing all vegetation and topsoil and compacting to at least 95% of the maximum
standard Proctor density. The fill should he benched into the portions of the hillside exceeding
20% grade.
Permanent unretained cut and fill slopes should be graded at 2 horizontal to 1 vertical or flatter
and protected against erosion by revegetation or other means. The risk of slope instability will
be increased if seepage is encountered in cuts and flatter slopes may be necessary. If seepage is
encountered in permanent cuts, an investigation should be conducted to determine if the seepage
will adversely affect the cut stability. This office should review site grading plans for the project
prior to construction.
SURFACE 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.
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
Kumar & Associates, Inc. 6 Project No. 19.7.670
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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. A swale will be required on the uphill,
western side of the proposed residence to divert sheet flow stemming from the
steep slope to the west of the proposed building area.
4) Roof downspouts and drains should discharge well beyond the limits of all
backfill.
5) Landscaping which requires regular heavy irrigation should be located at least 10
feet from foundation walls.
LIMITATIONS
This study has been conducted according to 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 field reconnaissance, review of published geologic reports, the exploratory pits located
as shown 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. lithe 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
pits 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 planning and design
purposes. We are not responsible for technical interpretations by others of our information. As
the project evolves, we should provide continued consultation and review and monitor the
implementation of ow recommendations. Significant design changes may require additional
analysis or modifications to 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 geoteehnical engineer.
Kumar & Associates, Inc. 0 Project No. 19-7-670
RLD/kac
Respectfully Submitted,
Kumar & Associates, Inc.
przvio
Robert L. Duran, E. I.
Reviewed by:
_0°0 REGis''a
Steven L. Paw1aP`�. 1522 vJ
........
cc: Breanna McC.umb cr,stifel.win)
John L. Taufer (llt a,sopris.net)
-10-
REFERENCES
Bryant, B., Shroba, R.R., Harding, A.E., and Murray, K.E., 2002, Geologic Map of the Storm
King Mountain Quadrangle, Garfield County, Colorado: U.S. Geological Survey,
Miscellaneous Field Studies Map MF-2389
Coe, J. A., and Others, 2003, Estimating Debris -Flow Probability Using Fan Stratigraphy,
Historic Records, and drainage Basin Morphology, Interstate 70 Highway Corridor,
Central Colorado, U. S. A. in Debris -Flow Hazards Mitigation, Mechanics, Prediction
and Assessment, Rickemann and Chen editors: Millpress, Rotterdam.
Widmann B. L. and Others, 1998, Preliminary Quaternary Fault and Fold Map and Data Base
of Colorado: Colorado Geological Survey Open -File Report 98-8.
Kirkham, R. M. and Rogers, W. P., 1985, Colorado Earthquake Data and Interpretations 1867
to 1985: Colorado Geological Survey Bulletin 46.
Peterson, M. D. and Others, 2014, Documentation for the 2014 Update of the National Seismic
Heard Maps: U. S. Geological Survey Open -File Report 2014-1091.
Kumar & Associates, Inc. ® Project No. 19-7-670
NOTE:
PIT 3 SOILS INFOMRATION
PRESENTED IN THE OWTS
REPORT.
150 0 150 300
SCALE -FEET
19-7-670
Kumar & Associates
LOCATION OF EXPLORATORY PITS
Fig. 1
PIT 1
EL. 100'
— 0
5
WC=10.8
DD=80
-200=49
WC=17.4
DD=91
PIT 2
EL. 96'
WC=10.2
+4-5
-200=50
WC=12.7
DD=86
0
5
10 10
LEGEND
a•
,
TOPSOIL; SILT AND CLAY, SANDY, ORGANIC, FIRM, MOIST TO SLIGHTLY MOIST, DARK BROWN.
FILL; SAND AND CLAY, STIFF, SLIGHTLY MOIST, DARK BROWN, ORGANIC.
GRAVEL (GM); SILTY, SANDY, MEDIUM DENSE, SLIGHTLY MOIST, MIXED BROWN,
SUB -ROUNDED ROCK.
SAND (SC-SM); VERY SILTY, CLAYEY, SCATTERED GRAVEL, MEDIUM DENSE, SLIGHTLY MOIST,
BROWN, SLIGHTLY CALCAREOUS.
2-INCH DIAMETER HAND DRIVEN LINER SAMPLE.
DISTURBED BULK SAMPLE.
NOTES
1. THE EXPLORATORY PITS WERE EXCAVATED WITH A BACKHOE ON NOVEMBER 4, 2019.
2. THE LOCATIONS OF THE EXPLORATORY PITS WERE MEASURED APPROXIMATELY BY PACING FROM
FEATURES SHOWN ON THE SITE PLAN PROVIDED.
3. THE ELEVATIONS OF THE EXPLORATORY PITS WERE MEASURED BY HAND LEVEL AND REFER TO
PIT 1 AS 100', ASSUMED.
4. THE EXPLORATORY PIT 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 PIT LOGS REPRESENT THE
APPROXIMATE BOUNDARIES BETWEEN MATERIAL TYPES AND THE TRANSITIONS MAY BE GRADUAL.
6. GROUND WATER WAS NOT ENCOUNTERED IN THE PITS AT THE TIME OF EXCAVATION. PITS WERE
BACKFILLED SUBSEQUENT TO SAMPLING.
7. LABORATORY TEST RESULTS:
WC = WATER CONTENT (%) (ASTM D 2216);
DD = DRY DENSITY (pcf) (ASTM D 2216);
+4 = PERCENTAGE RETAINED ON NO. 4 SIEVE (ASTM D 422);
-200= PERCENTAGE PASSING NO. 200 SIEVE (ASTM D 1140).
w
w
1-
w
0
19-7-670
Kumar & Associates
LOGS OF EXPLORATORY PITS
Fig, 2
CR 13L\DeT::.+A19/.73—o3.d✓9
SAMPLE OF: Very Silty Clayey Sand
FROM: Pit 1 CO 6'
WC = 17.4 %, DD = 91 pcf
ADDITIONAL COMPRESSION
- — UNDER CONSTANT PRESSURE
DUE TO WETTING
These teat eee.itn nppb' only to Iba
sempten 'Meant- The ient:ng terror!terror!hall not be e.prodVoud, .reap! in
fye, without leo WbII• nppnNol of
Kutner and Nfoolotee, tat. w.6A
Coneelidolten teel,nrl au[wmod In
aeenrdoMo With An 0-4546
1.0 APPLIED PRESSURE — KSF 10 100
19-7-670
Kumar & Associates
SWELL —CONSOLIDATION TEST RESULTS
Fig. 3
100
sD
e0
70
Q
6
30
20-
10
0
.001
I
,u
20
3D
e
g
0.
70
gp
100
io the
The
reproduced,
Inc.
In
ASTFI 07926,
HYDROMETER ANALYSIS
SIEVL ANALYSIS
24 MRS
43 Ill
--
-
-
.002
7 MRS
18 911M 68AIM
1 1
.095
1MR RL1a1022
I9A13
Ill
.009
4h'IN
1
.919
11.11R
-
l 11
.037
12e9
—
—.
111.11
.073
DIAMETER
0,100.
-__. .-
1
.160
M.C.
•
I
me
OF PARTICLES
974719989
010.0
I
1
I
i
I
1
1
ovum
0. 0
6 il,g►6
..
1
1
1
I
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2.0
MILLIMETERS
1
l
I i
t 2.3e 4.18
4 .ye'
I
1 1 11 I
9.8
171t811
-
1 'I
19
=GUARS
4. 1 1
-_
I
-
11
34.1
°TCl 11103
-
-
I IJ1I1
76,2
3' 3,7
1•
--
I
i
t
I
127
6'a
1
1
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I
1
r.•
1
{ -
200
tat
1!
{
I
I
I me
1 J 11
1,16
IN
CLAY TO SILT 1,
SA
SAND
GRAVEL
COBBLESCOBBLES
MEDIUM 'COARSE
FINE 11
GRAVEL. 5 % SAND 45 % SILT AND CLAY 50
LIQUID LIMIT PLASTICITY INDEX
SAMPLE OF: Very Silty Clayey Sand with Scattered Gravel FROM: Pit 2 ® 4'-5'
These test results apply only
samples which were tested.
1es11ng report shall not be
except In full, without the written
approval of Kumar & Associates,
Sieve analysl6 1es11n is perierrnud
aoeardanee wllh A51�M 089I3,
ASTM C136 aad/ar ASTM D1140.
19-7-670
Kumar & Associates
GRADATION TEST RESULTS
Fig, 4
of — Artificial Fill
Qac — Alluvium and Colluvium
Qc — Colluvium
Qls — Landslide Deposits
QTd — Oldest Debris Flow Deposits
Twl — Wasatch (Lower Member)
Ks — SS/MS/CS/conglomerate
Kw — Mesaverde (Williams Fork)
we — wheeler coal bed
Ki — Illes (Main Member)
Kic — Iles (Cozzette and Corcoran SS Members)
APPROXIMATE SCALE -MILES
19-7-670
Kumar & Associates
REGIONAL GEOLOGY MAP
Fig. 5
3[€rr>Aar & Associates, inc.`°
Geateshnicaf aid Materials Engineers
and Envirenrneltal ScierOsts
TABLE 1
SUMMARY OF LABORATORY TEST RESULTS
Proiect No.19-7-
SAMPLE LOCATION
NATURAL
MOISTURE
CONTENT
(%)
NATURAL
DRY
DENSITY
(an
GRADATION
PERCENT
P200 SINO.
ATTERBERG LIMITS
UNCONFINED
COMPRESSIVE
STRENGTH
(pst)
SOIL TYPE
BORING
DEPTH
(ft)
GRAVEL
(1/4)
SAND
(%)
PLASTIC
LIQUID LIMIT INDEX
(h) (%)
1
4
10.8
80
49
Very Silty Clayey Sand
6
17.4
91
Very Silty Clayey Sand
2
4 - 5
10.2
5
45
50
Very Silty Clayey Sand
with Scattered Gravel
7
12.7
86
Slightly Silty Sand
L -