HomeMy WebLinkAboutSoils Report 11.12.2019Kumar & Associates, Inc.®
Geotechnical and Materials Engineers
and Environmental Scientists
An Employee Owned Company
5020 County Road 154
Glenwood Springs, CO 81601
phone: (970) 945-7988
fax: (970) 945-8454
email: kaglenwood@kumarusa.com
www.kumarusa.com
Office Locations: Denver (HQ), Parker, Colorado Springs, Fort Collins, Glenwood Springs, and Summit County, Colorado
SUBSOIL STUDY
FOR FOUNDATION DESIGN
PROPOSED HEMP PROCESSING FACILITY
340 CHIPPERFIELD LANE
EAST OF DRY HOLLOW ROAD
SOUTH OF SILT, GARFIELD COUNTY
COLORADO
PROJECT NO. 19-7-628
NOVEMBER 12, 2019
PREPARED FOR:
SR EXTRACTIONS
ATTN: DAN MACFARLANE
340 CHIPPERFIELD LANE
SILT, COLORADO 81652
(dnnacfar latie rlsr-extractions.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 -
FLOOR SLABS - 4 -
UNDERDRAIN SYSTEM - 5 -
SURFACE DRAINAGE - 5 -
SEPTIC FIELD - 6 -
LIMITATIONS - 6 -
FIGURE 1 - LOCATION OF EXPLORATORY BORINGS
FIGURE 2 - LOGS OF EXPLORATORY BORINGS
FIGURE 3 - LEGEND AND NOTES
FIGURE 4 - SWELL -CONSOLIDATION TEST RESULTS
FIGURES 5 AND 6 — USDA GRADATION TEST RESULTS
TABLE 1- SUMMARY OF LABORATORY TEST RESULTS
Kumar & Associates, Inc. ® Project No. 19.7-628
PURPOSE AND SCOPE OF STUDY
This report presents the results of a subsoil study for a proposed hemp processing facility to be
located at 340 Chipperfield Lane, south of Silt, 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 SR Extractions, dated October 15, 2019.
A field exploration program consisting of exploratory borings was conducted to obtain
information on the 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, recommendations
and other geotechnical engineering considerations based on the proposed construction and the
subsurface conditions encountered.
PROPOSED CONSTRUCTION
The building is proposed in the area between Exploratory Borings 1 and 2 as shown on Figure 1.
We assume excavation for the building will have a maximum cut depth of about 3 feet below the
existing ground surface. The building will be a one-story steel frame/metal skin structure with a
slab -on -grade floor. For the purpose of our analysis, foundation loadings for the structure were
assumed to be typical of the proposed type of construction and relatively light for walls and
moderate for columns.
If building loadings, location or grading plans are significantly different from those described we
should be notified to re-evaluate the recommendations contained in this report.
SITE CONDITIONS
The site had been graded flat with up to 6 foot cuts and there was no vegetation in the building
area at the time of our site visit. The surrounding natural areas were vegetated with scattered
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junipers, grass and weeds. There is an existing greenhouse directly southwest of the proposed
processing facility. The natural terrain slopes moderately down to the southwest at grades of 8 to
10 percent. There are sandstone outcrops to the northwest of the building area. There is a dry
pond to the south and a creek about 150 feet southwest of the building area.
FIELD EXPLORATION
The field exploration for the project was conducted on October 30, 2019. Two exploratory
borings were drilled in the building area and two profile borings were drilled in the septic area at
the locations shown on Figure 1 to evaluate the subsurface conditions. The borings were
advanced with 4 -inch diameter continuous flight auger powered by a truck -mounted CME -45B
drill rig. The borings were logged by a representative of Kumar & Associates, Inc.
Samples of the subsoils were taken with 1% inch and 2 inch I.D. spoon samplers. The samplers
were driven into the subsoils 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 profiles encountered at the site are shown on Figure 2. Below
about 11/2 to 7 feet of expansive clay, hard sandstone bedrock of the Wasatch Formation was
encountered down to the maximum depth drilled of 16 feet. Drilling in the bedrock was difficult
with depth due to its hardness and practical auger refusal was encountered in Boring 2 at 6 feet.
Laboratory testing performed on samples obtained during the field exploration included natural
moisture content and density. Swell -consolidation testing was performed on relatively
undisturbed drive samples of the clay subsoils. The swell -consolidation test results, presented on
Figure 4, indicate low compressibility under relatively light surcharge loading and a low to
moderate expansion potential when wetted under a constant light surcharge. The laboratory
testing is summarized in Table 1.
Kumar & Associates, Inc. ® Project No. 19-7-628
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No free water was encountered in the borings at time of drilling. The subsoils and bedrock were
slightly moist.
FOUNDATION BEARING CONDITIONS
The clay subsoils encountered at the site possess low to moderate expansion potential when
wetted. The expansion potential can probably be mitigated by sub -excavation or load
concentration to reduce or prevent swelling in the event of wetting below the foundation bearing
level. Surface runoff, landscape irrigation, and utility leakage are possible sources of water
which could cause wetting.
DESIGN RECOMMENDATIONS
FOUNDATIONS
Considering the subsurface conditions encountered in the exploratory borings and the nature of
the proposed construction, we recommend the processing facility be founded with spread
footings placed on undisturbed natural soils or bedrock.
The design and construction criteria presented below should be observed for a spread footing
foundation system.
1) Footings placed on the undisturbed natural soils or bedrock can be designed for an
allowable bearing pressure of 4,000 psf. The footings placed on clay should also
be designed for a minimum dead load pressure of 1,000 psf. In order to satisfy
the minimum dead load pressure under lightly loaded areas, it may be necessary
to concentrate loads by using a grade beam and pad system. Wall -on -grade
construction is not recommended at this site to achieve the minimum dead load.
As an alternative, to avoid the need for a minimum dead load, the expansive clay
soils could be sub -excavated down to the sandstone bedrock and design footing
grade could be re-established with 3/ -inch road base placed in thin lifts and
compacted to at least 98% of the maximum standard Proctor density at a moisture
content near optimum.
2) Based on experience, we expect initial settlement of footings designed and
constructed as discussed in this section will be up to about 1 inch. There could be
Kumar & Associates, Inc. ® Project No. 19-7-628
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additional movement of around 1/2 to 1 inch if the clay bearing soils were to
become wet.
3) The footings should have a minimum width of 16 inches for continuous footings
and 24 inches for isolated pads.
4) Continuous foundation walls should be reinforced top and bottom to span local
anomalies and limit the risk of differential movement. One method of analysis is
to design the foundation wall to span an unsupported length of at least 14 feet.
Foundation walls acting as retaining structures (if any) should also be designed to
resist a lateral earth pressure computed on the basis of an equivalent fluid unit
weight of at least 55 pcf for backfill consisting of the on-site fine-grained soils.
5) 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 the exterior grade is typically used in this
area.
6) Prior to the footing construction, any existing fill, topsoil and loose or disturbed
soils should be removed and the footing bearing level extended down to
competent bearing soils.
7) A representative of the geotechnical engineer should observe all footing
excavations prior to concrete placement to evaluate bearing conditions.
FLOOR SLABS
The on-site clay soils possess an expansion potential and slab heave could occur if the subgrade
soils were to become wet. To reduce the expansion potential, we recommend that the clay soils
be sub -excavated below slab areas at least 2 feet and replaced with 3/ -inch road base compacted
to at least 95% of the maximum standard Proctor density at a moisture content near optimum.
Slab -on -grade construction may be used provided precautions are taken to limit potential
movement and the risk of distress to the building is accepted by the owner.
To reduce the effects of some differential movement, nonstructural floor slabs should be
separated from all bearing walls and columns 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
Kumar & Associates, Inc. ® Project No. 19-7-628
5
transmitted to the upper structure. This detail is also important for wallboards, stairways and
door frames. Slip joints which will allow at least 11 inches of vertical movement are
recommended. Floor slab control joints should be used to reduce damage due to shrinkage
cracking. Slab reinforcement and control joints should be established by the designer based on
experience and the intended slab use.
Required fill beneath slabs should consist of imported granular soil, excluding topsoil and rock
larger than 3 inches or 3/ -inch road base. The fill should be spread in thin horizontal lifts,
adjusted to at or above optimum moisture content, and compacted to at least 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.
We recommend vapor retarders conform to at least the minimum requirements of ASTM E1745
Class C material. Certain floor types are more sensitive to water vapor transmission than others.
For floor slabs bearing on angular gravel or where flooring system sensitive to water vapor
transmission are utilized, we recommend a vapor barrier be utilized conforming to the minimum
requirements of ASTM El 745 Class A material. The vapor retarder should be installed in
accordance with the manufacturers' recommendations and ASTM E1643.
UNDERDRAIN SYSTEM
An underdrain system should not be needed for the proposed slab -on -grade floor construction.
SURFACE DRAINAGE
The following drainage precautions should be observed during construction and maintained at all
times after the processing facility 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.
Kumar & Associates, Inc. ® Project No. 19-7-628
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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.
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 6 inches in the first 10 feet in unpaved areas and a minimum slope of 2'/2
inches in the first 10 feet in paved areas.
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. Consideration should be given to use of xeriscape to
reduce the potential for wetting of soils below the building caused by irrigation.
SEPTIC FIELD
Two profile borings, PB -1 and PB -2, were drilled at locations as shown on Figure 1. Results of
gradation analyses performed on the subsoils and weathered bedrock are presented on Figures 5
and 6. The soils encountered in the profile borings consist of 4 to 6 feet of silt loam and sandy
loam overlying hard sandstone bedrock.
Based on the subsurface conditions encountered, the tested area should be suitable for an
elevated conventional infiltration septic disposal system or a pumped system with sand filter. It
will probably be preferable to favor Profile Boring 1 area for the disposal field due to the greater
soil depth. A civil engineer should design the infiltration septic disposal system.
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
Kumar & Associates, Inc. ® Project No. 19-7-628
7
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.
Respectfully Submitted,
Kumar & Associates, loc.
Daniel E. Hardin, P
Reviewed by:
:�
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.
Steven L. Pawlak, P.E.
DEH/kac
Kumar & Associates, Inc. ® Project No. 19-7-628
10 0 10 20
APPROXIMATE SCALE -FEET
1 -t
lS
�1 • I
BORI G 2
.ur
•
a1 Ct
BORING 1
•
PROFILE BORING 1
•
PROFILE BORING 2
19-7-628
Kumar & Associates
LOCATION OF EXPLORATORY BORINGS
Fig. 1
- 0
5
w
w
w -
= 10
- 15
BORING 1
/
/
/
/
/
18/12
WC=7.8
DD=122
38/12
WC=8.7
DD=130
50/1
50/1
BORING 2
50/1
50/1
PROFILE BORING 1 PROFILE BORING 2
3- 9/12
GRAVEL=6
SAND=26
SILT=54
CLAY=14
- 7
1 50/3
50/5
GRAVEL=16
SAND=32
SILT=46
CLAY=6
0
5
10
15
20 20 -
19-7-628
Kumar & Associates
LOGS OF EXPLORATORY BORINGS
Fig. 2
LEGEND
18/12
CLAY (CL): SANDY, SILTY, VERY STIFF, SLIGHTLY MOIST, BROWN. (SANDY LOAM)
CLAY AND SILT (CL—ML): SANDY, GRAVELLY, VERY STIFF, SLIGHTLY MOIST, BROWN. PROFILE
BORING 1 ONLY. (SILT LOAM)
WEATHERED SILTSTONE/SANDSTONE: HARD, SLIGHTLY MOIST, BROWN. WASATCH FORMATION.
PROFILE BORING 2 ONLY.
SANDSTONE BEDROCK: HARD, SLIGHTLY MOIST, LIGHT BROWN. WASATCH FORMATION
DRIVE SAMPLE, 2—INCH I.D. CALIFORNIA LINER SAMPLE.
DRIVE SAMPLE, 1 3/8—INCH I.D. SPLIT SPOON STANDARD PENETRATION TEST.
DRIVE SAMPLE BLOW COUNT. INDICATES THAT 18 BLOWS OF A 140—POUND HAMMER
FALLING 30 INCHES WERE REQUIRED TO DRIVE THE SAMPLER 12 INCHES.
PRACTICAL AUGER REFUSAL.
NOTES
1. THE EXPLORATORY BORINGS WERE DRILLED ON OCTOBER 30, 2019 WITH A 4—INCH—DIAMETER
CONTINUOUS—FLIGHT POWER AUGER.
2. THE LOCATIONS OF THE EXPLORATORY BORINGS WERE MEASURED APPROXIMATELY BY TAPING
FROM FEATURES SHOWN ON THE SITE PLAN PROVIDED.
3. THE ELEVATIONS OF THE EXPLORATORY BORINGS WERE NOT MEASURED AND THE LOGS OF THE
EXPLORATORY BORINGS ARE PLOTTED TO DEPTH. THE SITE WAS RELATIVELY FLAT.
4. THE EXPLORATORY BORING LOCATIONS 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 D2216);
DD = DRY DENSITY (pcf) (ASTM D2216);
GRAVEL = Percent retained on No. 10 Sieve
SAND = Percent passing No. 10 sieve and retained on No. 325 sieve
SILT = Percent passing No. 325 sieve to particle size .002mm
CLAY = Percent smaller than particle size .002mm
19-7-628
Kumar & Associates
LEGEND AND NOTES
Fig. 3
•
0 I
CONSOLIDATION - SWELL
CONSOLIDATION - SWELL
2
1
0
—1
— 2
— 3
2
1
0
— 1
— 2
3
—
SAMPLE OF: Sandy Clay with Shale
Fragments
FROM: Boring 1 ® 2.5'
WC = 7.8 %, DD = 122 pcf
EXPANSION UNDER
PRESSURE UPON
CONSTANT
WETTING
—
/
I
EXPANSION
PRESSURE
UNDER
UPON
CONSTANT
WETTING
TT
�1
These test results apply only to the
samples tested. The testing report
shall not be repr duced, except in
full. without the written approval of
Kumar and Aeaoclates, Inc. Swell
Consolidation testi g performed In
accordance with ASTM D-4546.
10 APPLIED PRESSURE — KSF
10
140
1 0 APPLIED PRESSURE — KSF
10
10D
19-7-628
Kumar & Associates
SWELL—CONSOLIDATION TEST RESULTS
Fig. 4
SAMPLE OF: Sandy Clay with Shale
Fragments
FROM: Boring 1 CSD 5'
WC = 8.7 %, DD = 130 pcf
EXPANSION UNDER
PRESSURE UPON
CONSTANT
WETTING
—
/
I
These test results apply only to the
samples tested. The testing report
shall not be repr duced, except in
full. without the written approval of
Kumar and Aeaoclates, Inc. Swell
Consolidation testi g performed In
accordance with ASTM D-4546.
1 0 APPLIED PRESSURE — KSF
10
10D
19-7-628
Kumar & Associates
SWELL—CONSOLIDATION TEST RESULTS
Fig. 4
PERCENT RETAINED
HYDROMETER ANALYSIS
SIEVE ANALYSIS
24 HR. 7 HR
045 MIN,
10
20
30
40
50
60
70
80
90
100
TIME READINGS
1515114, 604.01. 12.48i. 114N.
U.S. STANDARD SERIES 1 CLEAR SQUARE OPENINGS
1 MIN.
x325 #140 #60 #35 #18 #10 #4 3 3/4• 1 112" 3' S•17
001 002 005 009 .019 045 .106 .025 .500 1,00 2.00 4.75 95 19.0 37.5 76.2 152 203
DIAMETER OF PARTICLES IN MILLIMETERS
V. FINE 1 FINE 1 MEDIUM I I COARSE IV- COAAsE SMALL ] MEO8JM O L
SILT
1 LARGE
COBBLES
GRAVEL 6 % SAND 26 %
SILT 54 % CLAY 14 %
USDA SOIL TYPE: SILT LOAM FROM: Profile Boring 1 @ 3'
90
BO
70
60
50
40
30
20
10
0
PERCENT PASSING
19-7-628
H-PvKUMAR
USDA GRADATION TEST RESULTS
Fig. 5
HYDROMETER ANALYSIS
SIEVE ANALYSIS
24
„45 MAN.
TIME READINGS I
HR. 7 HR 1 MIN.
15 MIN. 60MN. WIN, IMIN. #325
U.S. STANDARD SERIES I CLEAR SQUARE OPENINGS
#140 #60 #35 #18 #10 #4 3/8' 314' 11/2" 3" 5"6" 64
nn
PERCENT RETAINED
(0 CO J a) 01 A W N
O
0 O 0 0 0 0 0 O C
N W A 01 0) J m (D
O O O O O
0 O O C
PERCENT PASSING
Iuu
.001 .002
.005 .009 019 .045 .106 .025 .500 1.00 2.00 4.75 9 5 19.0 37.5 76.2 152 203 V
DIAMETER OF PARTICLES IN MILLIMETERS
GRAVEL
CLAY
SILT
r INE I NNE 1 AIEP4JM 1 CO1ni5E. N•�
SMALL 1 WWI1 LAMESAND
COBBLES
GRAVEL 16 % SAND 32 % SILT 46 % CLAY 6 %
USDA SOIL TYPE: SANDY LOAM FROM: Profile Boring 2 @ 1'
19-7-628
H-PtiKUMAR
USDA GRADATION TEST RESULTS
Fig. 6
Kumar & Associates, Inc.®
Geotechnical and Materials Engineers
and Environmental Scientists
TABLE 1
SUMMARY OF LABORATORY TEST RESULTS
Project No. 19-7-628
SAMPLE LOCATION
NATURAL
MOISTURE
CONTENT
(%)
NATURAL
DRY
DENSITY
(pcf)
GRADATION
USDA SOIL TEXTURE
SOIL TYPE
BORING
DEPTH
(ft)
GRAVEL
(%o)
SAND
(%)
SILT&CLAY
(%)
GRAVEL
(%)
SAND
(%)
SILT
(%)
CLAY
(°/u)
1
2Y2
7.8
122
Sandy Clay with Shale
Fragments
Sandy Clay with Shale
Fragments
5
8.7
130
Profile
Boring 1
3
6
26
54
14
SILT LOAM
Profile
Boring 2
1
16
32
46
6
SANDY LOAM