HomeMy WebLinkAboutGeotechnical Evaluation ReportGeotech n ica I Eva luation
Report
Rifle Compressor Station lmprovements
County Road 264
Rifle, Colorado
VIVID Project No.: D22-L-266
VIE'
EngíneerÍng Eroup
Only the client or it's designated representatives may use this document
and only for the specific project for which this report was prepared.
April7,2O22
Report prepared for:
Brett Atherton
Senior Project Engineer
EN Engineering
9777 Pyramid Court, Suite 200
Englewood, Colorado 8OLL2
batherton @enengineering.com
GEOTECHN ICAI EVALUATION REPORT
Rifle Compressor Station lmprovements
County Road 264
Rifle, Colorado
VIVID Project No.: D22-1-255
Prepared by:
Thomas J. Nevin, PE
Senior Geotechnical Engineer
Brysen T. Mustain, PG
Engineering Geologist
VIVID Engineering Group, lnc.
3885 Forest Street
Denver, Colorado 8O2O7
(303) ee4-s1s3
J,
4/7 /2022
Table of Contents
1_.0 tNTRODUCT|ON.............
l.l GENERAL
L
1
1
7
3
3
3
3
5
5
5
5
6
7
8
8
8
8
8
9
9
1.2 PROJECT DESCRIPTION
1.3 PURPOSE AND SCOPE
2.O FIELD EXPLORATION AND LABORATORY TESTING.......
2.1_ FTELD EXP1OR4T1ON.................
2.2 GEOTECH N ICAL LABORATORY TESTI NG
2.3 ANALYTICAL LABORATORY TESTING
3.0 strE coNDtÏoNs
3.l SURFACE
3.2 GEO1OGY................
3.3 SEtSMtC|TY .............
3.4 SUBSURFACE ..........
3.4.1 Groundwater.......
4.0 CONCLUSIONSAND RECOMMENDATIONS.....
4. 1- GEOTECHN ICAL FEASI BILIW OF PROPOSED CONSTRUCTION.......,......
4.2 CONSTRUCTION CONSIDERATIONS
4.2.2Site Preparation and Grading
4.2.3 Excavation Characteristics
4.2.4 tll Materials
4.2.5 Utility Trench Backfill
4.2.6 Compaction Requirements ..
4.2.7 Conslruction in Wet or Cold Weather
4.2.8 Construction Testing and Observation
4.2.9 Surface Drainage and Landscaping
4.2.10 Permanent Cut and Fill Slopes
4.3 FOU NDATION RECOM M ENDATIONS
4.3.1 Shallow Foundation Recommendations..........
4.4 FLOOR SYSTEMS
10
10
t7
72
72
t2
72
12
t4
744.4.1 Slab-on-Grade Floor System
4.5 EXTERTOR CONCRETE FLATWORK/SLABS-ON-GRADE....,....,. ..........,.........14
4.6 CORROSTVITY AND CONCRETE ......1s
4.6.L Corrosion Potential ..................15
4.6.2 Chemical Sulfate Susceptibility and Concrete Type........ .......................16
5.0 ADDITIONAL SERVICES & LIMITATIONS L7
5.2 LIMITATIONS
Figure 1: Vicinity Map
Figure 2: Field Exploration Plan
Appendix A: Logs of Exploratory Boríngs
Appendix B: Geotechnical Laboratory Test Results
Appendix C: Analytical Laboratory Test Results
Appendix D: Site Photos
Appendix E: lmportant lnformation About This Geotechnical Engineering Report
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1.0 INTRODUCTION
1-.1 GENERAL
This report presents the results of a geotechnical investigation performed for the proposed improvements
to the Rifle Compressor Station located along County Road 264, approximately % of a mile west of West
2nd Street in Rifle, Colorado. An attached Vicinity Map (Figure L) shows the general location of the project,
Our investigation was performed for EN Engineering and was authorized by Mr. Brett Atherton.
This report includes our recommendations relating to the geotechnical aspects of project design and
construction. The conclusions and recommendations stated in this report are based upon the subsurface
conditions found at the locations of our exploratory borings at the time our exploration was performed.
They also are subject to the provisions stated in the report section titled Additional Services &
Limitations. Our findings, conclusions, and recommendations should not be extrapolated to other areas
or used for other projects without our prior review. Furthermore, they should not be used if the site has
been altered, or if a prolonged period has elapsed since the date of the report, without VIVID's prior
review to determine if they remain valid,
1.2 PROJ ECT DESCRI PTION
We understand the proposed project consists of the demolition of the existing compressor building and
the construction of a new compressor building that will house 2 to 3 compressors. The new compressor
building will have plan dimensions of approximately 30 by 75 feet. We assume the building will be one-
story, steel framed with no basement construction. Additional improvements to the facility will include a
new instrument air building/system, new filter separators, new control building, new drain tanks, new
piping and other miscellaneous improvements. We also assume it will be desired to support the structures
on shallow foundations. We assume pavements will not be part of this project.
Loading information for the building and compressors have not been provided at this time. We assume
building column loads will range from 50 to 100 kips and wall loads will be on the order of 1 to 2 kips per
linear foot. We also assume each compressor will be supported on a mat foundation with an assumed
bearing pressure of 1,500 pounds per square foot (psf) or less and each compressor foundation will have
foundation dimensions on the order of 12 by 20 feet
Based upon the development at the existing compressor station, we assume cuts and fills will be on the
order of 1 foot or less to achieve the desired grade. This does not include deeper excavations that will be
required for foundations, utilities, etc., that will likely range from approximately 3 to 5 feet or so in depth
unless deep foundation elements (i.e. drilled piers) are required'
lf the type of construction or actual structure loads vary significantly from those assumed above, VIVID
should be notified in orderto revise our recommendations, if required'
1.3 PURPOSE AND SCOPE
The purpose of our investigation was to explore and evaluate the subsurface conditions at the structure
location on the site and, based upon the conditions found, develop recommendations relating to the
geotechnical aspects of project design and construction. Our conclusions and recommendations in this
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report are based upon analysis of the data from our field explorat¡on, laboratory tests, and our experience
with similar soil ancl geologic conditions in the area.
VIVID's scope of services included:
¡ A visual reconnaissance to observe surface and geologic conditions at the project site and locating
the exploratory borings;
¡ Notification of the Colorado 811 one-call center to have existing utilities located and marked in
the vicinity of the boring, and hydro-excavation of an "L-shaped" excavation was performed at
each boring location in order to verify underground utilities were not present at the boring
location;
¡ The drilling of two exploratory borings near the proposed compressor building on the property,
which was selected based upon the proposed site layout, location of existing structures and
utilities;
¡ Laboratory testing of selected samples obtained during the field exploration to evaluate relevant
physical and engineering properties of the soil and bedrock;
¡ Evaluation and engineering analysis of the field and laboratory data collected to develop our
geotechnical conclusions and recommendations; and
¡ Preparation of this report, which includes a description of the proposed project, a description of
the surface and subsurface site conditions found during our investigation, our conclusions and
recommendations as to foundation construction, other related geotechnical íssues, and
appendices which summarize our field and laboratory investigations.
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2.0 FIELD EXPLORATION AN D LABORATORY TESTING
2.1. TIELD EXPLORATION
A field exploration performed on March 9 and 10, 2022,included drilling two exploratory borings at the
approximate locations indicated on the attached Field Exploration Plan (Figure 2). The borings were
drilled nearthe approximate footprint of the proposed compressor building and were advanced to depths
of approximately 53.5 and 54 feet below the existing ground surface. The borings were terminated due
to drilling refusal.
The borings were advanced using a truck-mounted CME-75 drill rig equipped with 6-inch diameter, air-
hammer (ODEX) drilling system. Samples were taken with a California-type sampler (2.0-inch LD./2.5-inch
O.D.) and by bulk methods. Penetration tests were obtained at the various sample depths as well.
Appendix A to this report includes logs describing the subsurface conditíons. The lines defining
boundaries between soil and rock types on the log are based upon drill behavior and interpolation
between samples and are therefore approximate. Transition between soil and rock types may be abrupt
or may be gradual.
2.2 GEOTECH N ICAL LABORATORY TESTI NG
Laboratory tests were performed on selected samples to estimate their relative engineering properties.
Tests were performed in general accordance with the following methods of ASTM or other recognized
standards-setting bodies, and local practice:
¡ Description and ldentification of Soils (Visual-Manual Procedure)
o Moisture Content and Unit Weight of Soils
¡ Sieve Analysis
o Atterberg Limits
¡ Swell/SettlementTest
o Unconfined Compressive Strength
Results of the geotechnical laboratory tests are presented in the report text, where applicable, and
included in Appendix B of this report. Selected test results are also shown on the boring logs in Appendix
A.
2.3 ANALYTICAL LABORATORY TESTING
Analytical testing for soil corrosivity was performed on a selected sample and included the following tests
.pH
o Resistivity
¡ Redox Potential
o Water-solubleSulfates
¡ Water-solubleChlorides
¡ Sulfides
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Results of the analytical laboratory tests are presented in the report text, where applicable, and included
in Appendix C of this report.
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3.0 SITE CONDITIONS
3.1 SURFACE
The subject site consists of the existing Rifle Compressor Station with several one-story metal framed
buildings and various equipment and piping. The site gently sloped downward from northeast to
southwest with a maximum difference in elevation of approximately 8 feet across the site. At the time of
the investigation, the site was covered by a thin layer of gravel. Pioneer Ditch is located approximately
300 feet south of the compressor station site'
3.2 GEOLOGY
Prior to drilling, the site geology was evaluated by reviewing available geologic information including the
USGS Geologic Map of the Rifle Quadrangle, Garfield County, Colorado (Ralph R. Shroba and Robert B.
Scott, 1997). Mapping indicates the surficial soils in the general area of the project site predominantly
comprise of younger terraced alluvium consisting of sand, silt and clay. Bedrock consisting of shale of the
Wasatch Formation is present below the alluvium soils.
3.3 SEISMICITY
Based upon the geologic setting, subsurface soil and bedrock conditions, and low seismic activity in this
region, liquefaction is not expected to be a hazard at the site. Based on correlation of blow count data
(N-values) from the boring advanced during this evaluation, the subsurface soil and bedrock profiles
correspond with Site Class E of the 2015 lnternational Building Code (lBC). The intermediate design
acceleration values from IBC are presented below.
Table 1
Acceleration for Short Periods
The mapped spectral accelerations for short periods (ATC/USGS Seismic Design Web Services, 2022)
Site coefficient from Table 1613.3.3(1), 2015 IBC
Table 2
Acceleration for l-Second Period
= The mapped spectral accelerations for l-second period (ATC/Seismic Design Web Services, 2022)
= Site coefficient from Table 1613.3.3(2), 2015 IBC
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Ss
Fa
Sr
Fv
F,5s
2.3570.295
FvSrSor
3.50.078 o.782
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Based upon an Sor = 0.182 for the site, the Seismic Design Category is a "C" for occupancy category l, ll
or lll and a "D" for occupancy category lV.
3.4 SUBSURFACE
VIVID explored the subsurface conditions by drilling, logging, and sampling two exploratory borings at the
proposed site as shown approximately on Figure 2. The borings were drilled to depths of approximately
53.5 and 54 feet below the existing ground surface.
ln general, the subsurface condítions consisted of approximately 3 inches of a surficial gravel layer,
underlain by interbedded layers of lean clay with various amounts of sand and silt, silty sand and sandy
silt depths ranging from approximately 52 to 53 feet below the existing ground surface. Shale bedrock
was then encountered in both borings to the maximum depths of approximately 53.5 and 54 feet below
the existing ground surface. As mentioned previously, the borings were terminated due to drilling refusal
at depths of approximately 53.5 and 54 feet within very hard shale bedrock. The soil and bedrock layers
encountered in our borings are discussed further below:
Clav
The lean clay with various amounts of sand and silt was encountered underlying the surficial gravel layer
and was generally light brown, slightly moist to moist and soft to stiff in consistency. The clay extended
to a depth of approximately 52 to 53 feet below the existing ground surface. Swell/settlement testing
performed on samples of the clay indicated low expansion potential of 0.5 percent when wetted under
surcharge pressure of approximately 500 psf and low compression potential that ranged from 0.2 to 0.7
percent when wetted under surcharge pressure of approximately 1000 psf. Unconfined compressive
strength tests performed on clay samples exhibited compressive strengths ranging from approximately
681to 3O72psf .
Siltv Sand
A layer of silty sand was encountered in boring B-1 at depths of approximately 12 to 23 feet below the
existing ground surface and was generally light brown, moist and loose in relative density.
Swell/settlement testing performed on a sample of the sand indicated low compression potential of
approximately0.6percentwhenwettedundersurchargepressureofapproxímately1000psf. Unconfined
compressive strength testing performed on a sand sample exhibited a compressive strength of
approximately 1473 psf.
Sandv Silt
A layer of sandy silt was encountered in boring B-2 at depths of approximately 47 to 53 feet below the
existing ground surface and was generally light brown, moist and very stiff in consistency.
Shale Bedrock
The shale bedrock was observed to be grey and brown and moist. Field penetration testing (blow counts)
indicated the relative density of the bedrock materials were very hard. Shale bedrock was encountered
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at depths of approximately 52 and 53 feet below the existing ground surface and extended to the
maximum depth explored of approximately 54 feet below the existing ground surface.
The boring logs in Appendix A should be reviewed for more detailed descriptions of the subsurface
conditions at the boring locations explored.
3,4.1 Groundwater
Groundwater was not encountered in the borings during drilling. Groundwater levels commonly vary over
time and space depending on seasonal precipitation, water levels in the nearby Pioneer Ditch and
Colorado River, irrigation practices, land use, and runoff conditions. These conditions and the variations
they create often are not apparent at the time of field investigation. Accordingly, the soil moisture and
groundwater data in this report pertain only to the locations and times at which exploration was
performed. They can be extrapolated to other locations and times only with caution. lt should also be
noted that VIVID has not performed a hydrologic study to verify the seasonal high-water level.
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4.0 CONCLUSIONS AN D RECOM MENDATIONS
4. 1 G EOTECH N ICAL FEASI BI LITY O F PROPOSED CONSTRUCTION
We did not identify geotechnical condit¡ons we believe will preclude development of the site as planned,
provided the recommendations in this report are incorporated into the design and construction of the
project. Due to the presence of some surficial clay soils, we recommend that these clay soils be scarified,
moisture conditioned and recompacted prior to the placement of new fill materials.
The proposed compressor station and structures may be supported by shallow foundations, provided the
owner can accept the potential risk of differential foundation movement as discussed in this report. lf
some foundation movement cannot be tolerated, then the structures should be supported on a deep
foundation system. To help create a more uniform and stable platform on which to construct the
foundations and reduce the potential for movement, we recommend building foundations bear directly
on a minimum L2-inch-thick zone of imported granular structural fill. We recommend compressor
foundation elements be isolated from other foundation elements and floor slabs, and bear directly on a
minimum 24-inch-thick zone of imported granular structural fill.
The structural fill should comprise of material meeting CDOT Class I Structure Backfill specifications (see
Table 703.09, Section 703, CDOT Standard Specifications for Road and Brldge Construction, 2OZ1). lf
unstable conditions are present at the over-excavation level, stabilization of these materials may be
required with the use of geotextiles and/or gravel. Woven geotextiles such as Mifafi HP570, Mirafi RS580
or equivalent and geogrids such as Tensar BX 1200 or equivalent have been used for similar stabilization.
lf movement of the foundations is not desired, the structures may be supported on a deep foundation
such as drilled piers. We can provide design parameters and recommendations for drilled pier
construction, if desired.
4.2 CONSTRUCTION CONSI DERATIONS
4.2.L General
All site preparation and earthwork operations should be performed in accordance with applicable codes,
safety regulations and other local, State or Federal guidelines.
4.2.2SiLe Preparation and Grading
lnitial site work should consist of completely removing all gravel, loose natural soils and other deleterious
materials from all areas to be filled and areas to be cut. The foundation for the existing compressor station
and miscellaneous structures should be over-excavated and removed from the proposed building and
structure areas and replaced with compacted structural fill, as described later in this report. Any utilities
within the area should also be over-excavated and removed. Alternatively, the utilities can be grouted in
place.
All material should be removed for offsite disposal in accordance with local laws and regulations or, if
appropriate, stockpiled in proposed landscaped areas for future use. Excavations to remove existing site
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features must be backfilled and properly compacted. Areas to receive fill should U" "url'ffiiËä"geotechnical engineer prior to the placement of any fill materials.
After performing the required excavations and prior to the placement of any compacted fill and/or
structural elements, processing of the clay soil subgrade should be performed. This should include
scarifying the clay soil subgrade to a depth of at least 12 inches and compacting as recommended in
Section 4.2.6 of this report. Allfill materials should be placed on a horizontal plane and placed in loose
lifts not to exceed 8 inches in thickness, unless otherwise accepted by the geotechnical engineer.
4.2.3 Excavatio n Cha ra cteristics
Based upon the development at the site, we assume cuts and fills will be minimal at less than L foot to
achieve the desired grade. Util¡ty installation has not been revìewed, but special excavation conditions
are not anticipated. We anticipate excavation of the on-site overburden soils can be performed with
conventional heavy-duty earthmoving equipment'
All excavations must comply with applicable local, State and Federal safety regulations, and particularly
with the excavation standards of the Occupational Safety and Health Administration (OSHA). Construction
site safety, including excavation safety, is the sole responsibility of the Contractor as part of its overall
responsibility for the means, methods and sequencing of construction operations. VIVID's
recommendations for excavation support are intended for the Client's use in planning the project, and ín
no way relieve the Contractor of its responsibility to construct, support and maintain safe slopes. Under
no circumstances should the following recommendations be interpreted to mean that VIVID is assuming
responsibility for either construction site safety or the Contractor's activities.
We believe the soils on this site will classify as Type C materials using OSHA criteria. OSHA requires that
unsupported cuts in Type C materials be laid back to ratios no steeper lhan L%:L (horizontal to vertical).
ln general, we believe that these slope ratios will be temporarily stable under unsaturated conditions. lf
groundwater seepage were to occur, flatter slopes will be required. Please note that the actual
determination of soil type and allowable sloping must be made in the field by an OSHA-qualified
"competent person."
4.2.4 Ftl Materials
One, or a combination of, moisture treated (on-site soils) and granular structural fill (imported to site) will
be required for this project.
Scarifying, moisture treatment and recompaction of the on-site surficial soil materials will be required
prior to placement of fill materials. This generally requires adjusting the moisture content of the on-site
materials to above optimum moisture content (e.g. +L% fo +4% of optimum) and re-compact¡ng (see
Section 4.2.61. On-site soil materials can be re-used as moisture treated site grading materials provided
it can be properly broken down into a soil-like material and thoroughly moisture treated. The clay soils
should not be reused as structural fill at this site'
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Site Grading Fill:
On-site clay soils may be used for general site grading only, provided these materials are properly
processed (i.e. large pieces broken down to a soil-like consistency with particle sizes of less than three
inches), moisture-conditioned, and compacted. lf imported site grading fill is required at this site, it should
consist of a non-expansive, granular material with a maximum particle size of 2 inches, a liquid limit of
lc¡s than 30 pcrccnt, and a plasticity index of less than 6 percent. The fill should have between about l-0
and 30 percent passing the No. 200 sieve. A sample of any imported site grading fill material should be
submitted to our office for approval and testing at least 1 week pr¡or to stockpiling at the site.
lmported Structural Fill:
Any imported structural fill required at this site should consist of materials meeting the CDOT Class I
Structure Backfill specifications, as described in Section 703.09 of the 2021 CDOT Standard Specifications
for Road and Bridge Construction. A sample of any imported structural fill material should be submitted
to our office for approval and testing at least 1 week prior to stockpiling at the site. Specific
recommendations regarding depth of structural fill are presented in the following sections of this report
for foundations.
Fill should be compacted according to the recommendations in Section 4.2.6 of this report. We
recommend that a qualified representative of VIVID visit the site during excavation and during placement
of the structural fill to verify the soils exposed in the excavations are consistent with those encountered
during our subsurface exploration and that proper foundation subgrade preparation and placement is
performed.
4.2.5 Utility Trench Backfill
Rerl¿fill maforírl charrl¡,1 ¡nmnricaaf imnarfa¡{cfrrr¡frrrrlfillrn¡lhaaccanfi:lh¡fraanf nlanlma}fa¡ nra¡ni¡er rr¡rt,vr y rrsL vr l/rsrrr rrrsllLr, vrıqrrrv
soil, debris, trash, other deleterious matter and rock particles larger than 3 inches. However, backfill
material in the "pipe zone" (from the trench floor to l foot above the top of pipe) should not contain rock
particles larger than 1 inch. Strictly observe any requirements specified by the utility agency for bedding
and pipe-zone fill. ln general, backfill above the pipe zone in utility trenches should be placed in lifts of 6
to 8 inches, and compacted using power equipment designed for trench work. Backfill in the pipe zone
should be placed in lifts of I inches or less and compacted w¡th hand-held equipment. Compact trench
backfill as recommended in Section 4.2.6 of this report.
4.2.6 Compaction Req u irements
Fill materials should be placed in horizontal lifts compatible with the type of compaction equipment being
used, moisture conditioned, and compacted in accordance with the following criteria:
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Table 3
Compact¡on cations
L) ln non-structural or landscaped areas, the compaction specification may be reduced to 90 percent.
2) Where two or more "Fill Locations" coincide, the more stringent specification should be used.
Fill should be placed in level lifts not exceeding 8 inches in loose thickness and compacted to the specified
percent compaction to produce a firm and unyielding surface. lf field density tests indicate the required
percent compaction has not been obtained, the fill material should be reconditioned as necessary and re-
compacted to the required percent compaction before placing any additional material.
4.2.7 Construction in Wet or Cold Weather
Construction in wet weather will be problematic on this site due to the moisture-sensitive clayey soils.
During construction, grade the site such that surface water can drain readily away from the structure and
exterior flatwork areas. Promptly pump out or otherwise remove any water that may accumulate in
excavations or on subgrade surfaces and allow these areas to dry before resuming construction. The use
of berms, ditches and similar means may be used to prevent stormwater from entering the work area and
to convey any water off site efficiently.
lf earthwork is performed during the winter months when freezing is a factor, no grading fill, structural fill
or other fill should be placed on frosted or frozen ground, nor should frozen material be placed as fill,
Frozen ground should be allowed to thaw or be completely removed prior to placement of fill. A good
practice is to cover the compacted fill with a "blanket" of loose fill to help prevent the compacted fill from
freezing.
lf the structures are erected during cold weather, foundations, concrete slabs-on-grade, or other concrete
elements should not be constructed on frozen soil. Frozen soil should be completely removed from
beneath the concrete elements, or thawed, scarified and recompacted. The amount of time passíng
between excavation or subgrade preparation and placing concrete should be minimized during freezing
conditions to prevent the prepared soils from freezing. The use of blankets, soil cover or heating as
required may be utilized to prevent the subgrade from freezing,
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PERCENT
COMPACflONl
MOISTURE
CONTENTMATERIALTYPEF¡LL LOCAflON 2
95 minimum of
ASTM D 698
+Lto +4% of
optimum
Subgrade
Preparation
(all areas)
On-site Clay Soils
(12-inches Scarified, Moisture Treated,
Re-compacted)
95 minimum of
ASTM D 1.557
+2%of
optimum
lmported CDOT Class I Structure Backfill
(see Section 4.2.4)Structural Fill
+2%of
optimum
95 minimum of
ASTM D 1557
lmported CDOT Class I Structure Backfill
(see Section 4.2.4)
Exterior Flatwork
Areas
95 minimum of
ASTM D 698
+tto +4% of
optimumOn-site Clay Soils (see Section 4.2.4)General Site
Grading Fill
95 minimum of
ASTM D 698
+Lto +4% of
optimum(see Section 4.2.5)Utility Trenches
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4.2.8 Construction Testing and Observation
Tcsting and construction observation should take place under the direction of VIVID to support that
engineer's professional opinion as to whether the earthwork does or does not substantially conform to
the recommendations in this report. Furthermore, the opinions and conclusions of a geotechn¡cal report
are based upon the interpretation of a limited amount of information obtained from the field exploration.
It is therefore not uncommon to find that actual site conditions differ somewhat from those indicated in
the report. The geotechnical engineer should remain involved throughout the project to evaluate such
differing conditions as they appear, and to modify or add to the geotechnical recommendations as
necessary.
4.7.9 Surface Drainage and Landscaping
Positive drainage away from the structures is essential to the performance of foundations and flatwork
and should be provided during the life of the structures. Areas where pavements or slabs are constructed
adjacent to the structures should slope away at a minimum grade of 2 percent. All downspouts from roof
drains should be tight-lined to the on-site stormwater system or, at a minimum, cross all backfilled areas
such that they discharge all water away from the backfill zone and the structures. Drainage should be
created such that water is diverted off the site and away from backfill areas of adjacent structures.
ln order to help prevent the infiltration of surface water drainage into the subgrade below the proposed
structures, at least 12 inches of a low-permeable clay cap comprising cohesive, on-site clay soil or flow-fill
should be placed on the surface overlying the foundation wall structural fill, in any rock landscaping, and
non-structural areas around the structures that are not planned to have any exterior flatwork constructed,
4.2.10 Permanent Cut and Fill Slopes
lf required, permanent cut and fill slopes exposing the materials encountered in our borings are
--¡:^i-^¡^l ¡^ L^ ^t-Ll- ^r -l--- --r:^^ -- 1-4 ,L--:-^-t-l !- --^J:--lt -..^i^- i--- -^-l:t:^-dilLrLr[,rdr,tru LU us sLdurc dr srupc f duu> d5 stEcp d5 J.r Ururr¿ulrLdr [u verLlLdU uf luef ury Luf rurLtuf15. vve
believe that slope ratios of 4:L or flatter are more reliable if subjected to wetting, and present less of a
maintenance problem. New slopes should be revegetated as soon as possible after completion to reduce
erosion problems.
4.3 FOUNDATION RECOMMENDATIONS
4.3.1" Shallow Foundation Recommendations
Provided the following recommendations are complied with, the proposed compressor station,
compressor foundations and miscellaneous structures may be supported on a shallow spread footing
foundation, provided the owner can accept some foundation movement and associated risk of differential
foundation movement as discussed below. We recommend conventional shallow foundation elements
be designed with the following criteria:
a To help create a more uniform and stable platform on which to construct the foundations and
reduce the potential for movement, we recommend building foundations bear directly on a
minimum l2-inch-thick zone of imported granular structural fill. We recommend compressor
foundations bear directly on a minimum 24-inch-thick zone of imported granular structural fill.
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Foundations placed on properly prepared compacted soils or imported granular structural fill in
accordance with this report may be designed for an allowable bearing pressure of 2,000 psf. A
one-third increase in bearing capacity is allowable for transient loads (e.g. wind loads). All
foundations should be proportioned as much as practicable to minimize differential settlement.
provided all our recommendations are followed, the total movement of the compressor building
and miscellaneous structure foundations constructed as described above are projected to be on
the order of about L inch or less, with differential movement about half of the total movement.
The total movement of the compressor foundations constructed as described above are projected
to be on the order of about 7 to I-U2 inches, with differential movement about half of the total
movement.
Lateral loads may be resisted using a coefficient of friction for sliding, between the bottom of the
footing and the underlying soil, of 0.35 for foundations cast directly on granular (sand) fill soils. ln
addition, allowable passive resistance may be computed using an equivalent fluid density of 310
pounds per cubic foot (pcf) for the clay soils. Passive pressure may be combined with lateral
friction in designing for lateral loads. Passive earth pressure should be ignored within three feet
of finished grade.
Footing size should be determined by a structural engineer based on the actual structure loads
and the above provided maximum allowable soil bearing pressure; however, as a minimum, we
recommend isolated column footings be at least three feet wide. Continuous strip footings should
be at least two feet in width.
Exterior foundations should be protected from frost action. We recommend the footings be
protected with at least 24 inches of soil cover, or that which is required by local building codes,
whichever is greater.
A modulus of subgrade reaction, Kvr, of 100 pounds per cubic inch may be used for design of mat
foundations. Kvr refers to a one-foot square plate and should be adjusted for actual foundation
dimensions using the following equation (B is foundation width in feet):
/s+ l\2Ku=Kvl(. * J
A shear wave velocity of 450 feet per second and a poison's ratio of 0.4 may be used for the clay
soils at this site,
The foundation subgrade should be protected from wetting and drying prior to and after concrete
placement. Footings should be backfilled as soon as practical after concrete placement.
Under no circumstances may the footings be installed on non-engineered fill, topsoil, soft or
disturbed soils, construction debris, frozen soil, moisture sensitive soils, or within ponded water.
lf bearing soils or structural fill upon which the footings are to be constructed become loose or
disturbed, the subgrade should be recompacted to the requirements of structural fill or excavated
to firmer, undisturbed soils and replaced with structural fill or CLSM'
April 7, 2022
tit,V,oEÌnMwøm.te
The following table is a summary of the subsurface engíneering parameters based on the existing
subsurface condit¡ons and were estimated, or calculated, based on generally accepted engineering
correlations.
Table 4
Subsurface eeri Parameters
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4.4 FLOOR SYSTEMS
4.4.1- Slab-on-Grade Floor System
Slab-on-grade floor systems are considered acceptable provided the owner is willing to risk some slab
movement. lf floor movement cannot be tolerated, then a structurally supported floor system is
recommended.
The criteria presented below should be observed for design and construction of floor slabs on this site.
The construction details should be considered when preparing the project documents.
For concrete slab-on-grade design purposes, a modulus of subgrade reaction of 1-00 pounds per
cubic inch (pci) may be used in design of slabs placed on properly prepared compacted on-site
soils or imported granular structural fill as described herein.
Provided all our recommendations are followed, the total movement of slab-on-grade
constructed as described above are projected to be on the order of about 1 inch, with differential
movement about half of the total movement.
14 lPage
D22-1-266
a
O
Depth (ft)
lithology/ Þ-
Y Curve
Model
Average "N"
Value
Effectlve
Unit
Weight
(pcrl
Undralned
Cohesion
(psrl
Frlctlon
Angle
(deel
Strain
Factor, eso
Clay / Clay
without Free
Water
6 t20 1,000 n/a 0.013-9
9 -22
Clay / Clay
without Free
Water
3 1_15 430 n/a 0.02
22- 42
Clay / Clay
without Free
Water
7 125 1.,150 n/a 0.007
42-53
Clay / Clay
without Free
Water
15 130 2,600 n/a 0.005
53-54
Shale / Clay
without Free
Water
100 13s 5,900 n/a 0.004
April 7,2A22
/Êt'V,íingtnhßfftg grea
o Floor slabs should be separated from all bearing walls and columns with expansion joints that
allow unrestrained vertical movement. At door thresholds only, both interior and exterior slabs
can be dowelled into the foundation stem wall to resist movement that can create a trip hazard
or impede proper door oPeration'
¡ Floor slab controljoints should be used to reduce damage due to shrinkage cracking. Controljoint
spacing is a function of slab thickness, aggregate size, slump and curing conditions. The
requirements for concrete slab thickness, joint spacing and reinforcement should be established
by the designer based on experience, recognized design guidelines and the intended slab use.
Placement and curing conditions will have a strong impact on the final concrete slab integrity.
. Util¡ty lines should be provided with flex¡ble joints or oversized sleeves where they penetrate floor
slabs to prevent breakage caused by differential movement.
Where vibrating machinery will be installed in the building, the machine foundations should be physically
isolated from other foundations and slabs to reduce vibration damage. The design of such foundations
requires special analysis that is beyond the scope of this investigation. Please contact VIVID for additional
analysis and recommendations if machine vibrations will be an issue at this building.
4.5 EXTERIO R CONCRETE FLATWO RK/SLABS-O N-G RADE
The project will include exterior concrete for walkways, sidewalks, driveways, etc. Some potential for
differential movement and cracking is possible if the slabs are constructed directly upon the expansive
clay soils. While it is not likely that exterior slabs can be economically protected from distress, several
techniques are available to reduce the expected long-term movement of the slab, including:
o placement of a thick zone of imported, granular, non-expansive structural fill beneath slabs,
similar to the foundation structural fill described herein,
¡ At thresholds, thickened slabs can be doweled into the structure to avoid differential movement
and trip hazards,
¡ Avoidance of watering adjacent to slabs, and
¡ Structural reinforcement of slabs'
Even with the above mitigation techniques, movements of exterior slabs due to subgrade heave and
associated maintenance and repairs should be anticipated.
4.6 CORROSIVITY AND CONCRETE
4.6. l- Corrosion Potential
Laboratory testing was completed to provide data regarding corrosivity of onsite soils. Our scope of
services does not include corrosion engineering and, therefore, a detailed analysis of the corrosion test
results is not included. A qualified corrosion engineer should be retained to review the test results and
design protective systems that may be required'
Laboratory chloride concentration, sulfate concentratioî, ÞH, and electrical resistivity tests were
performed on a sample of onsite materials obtained during our field investigation. The results of the tests
are included in Appendix C to this report and are summarized below in Table 5.
15 lPage
D22-1-266
April 7, 2A22
,/,:
Êogl,ffiúng fnu¡t
Table 5
Summary of Laboratory Soil Corrosivity Testing
Metal and concrete elements in contact with soil, whether part of a foundation system or part of a
supported structure, are subject to degradation due to corrosion or chemical attack. Therefore, buried
metal and concrete elements should be designed to resist corrosion and degradation based on accepted
practices.
Based on the "10-point" method developed by the American Water Works Association (AWWA) in
standard AWWA CLOSIA2'J,5, the corrosivity test results indicate that the onsite materials have corrosive
potentialjust based upon the low electrical resistivity alone. We recommend that a corrosion engineer be
consulted to recommend appropriate protective measures, if required.
4.6.2 Chemical Sulfate Susceptibility and Concrete Type
The degradation of concrete or cement grout can be caused by chemical agents in the soil or groundwater
that react wíth concrete to either dissolve the cement paste or precipitate larger compounds within the
concrete, causing cracking and flaking. The concentration of water-soluble sulfates in the soils is a good
indicator of the potential for chemical attack of concrete or cement grout. The American Concrete
lnstitute (ACl) in their publication Guide to Durable Concrete (ACl 201.2R-08) provides guidelínes for this
assessment.
The concentration of water-soluble sulfates measured on subsurface materials submitted for testing
represents Class 0 exposure of sulfate attack on concrete exposed to the soils per CDOT Standard
Specifications for Road and Bridge Construction,2OZI, Section 60L.04.
16 lPage
D22-1-266
Boring
No.
Sample
Depth
(ftt
Material
Water
Soluble
Chloride
t%t
pH
Redox
Potent¡al
(mvl
Resistivity
(ohm-cmf
Water
Soluble
Sulfate (%)
Sulfide
Content
B-1 0-5 Clay 0.2331 8.1 231 260 0.0s18 Trace
April 7,2A22
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5.0 ADDITIONAL SERVICES & LIMITATIONS
5. ]" ADDITIONAL SERVICES
Attached to this report is a document by the Geoprofessional Business Association (GBA) that summarizes
limitations of geotechnical reports as well as additional services that are required to further confirm
subgrade materials are consistent with that encountered at the specific boring locat¡ons presented in this
report. This document should be read in its entirety before implementing design or construction
activities. Examples of other services beyond completion of a geotechnical report are necessary or
desirable to complete a project satisfactorily include:
o Review of design plans and specifications to verify that our recommendations were properly
interpreted and implemented.
¡ Attendance at pre-bid and pre-constructlon meetings to highlight important items and clear up
misunderstandings, ambiguities, or conflicts with design plans and specifications.
¡ Performance of construction observation and testing which allows verification that existing
materials at locations beyond our boring are consistent with that presented in our report,
construction is compliant with the requirements/recommendations, evaluation of changed
conditions.
5.2 LIMITATIONS
This work was performed in a manner consistent with that level of care and skill ordinarily exercised by
other members of VIVID's profession practicing ín the same locality, under similar conditions and at the
date the services are provided. Our conclusions, opinions, and recommendations are based on a limited
number of observations and data. lt is possible that conditions could vary between or beyond the data
evaluated. VIVID makes no other representation, guarantee, or warranty, express or implied, regarding
the services, communication (oral or written), report, opinion, or instrument of service provided.
This report may be used only by the Client and the registered design professional in responsible charge
and only for the purposes stated for this specific engagement within a reasonable time from its issuance,
but in no event later than two (2) years from the date of the report.
The work performed was based on project information provided by Client. lf Client does not retain VIVID
to review any plans and specifications, including any revisions or modifications to the plans and
specifications, VIVID assumes no responsibility for the suitability of our recommendations. ln addition, if
there are any changes in the field to the plans and specifications, Client must obtain written approvalfrom
VIVID's engineer that such changes do not affect our recommendations. Failure to do so will vitiate VIVID's
recommendations.
lTlPage
D22 1-266
April 7, 2022
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l, ururoEngineerins Group,/ / saas Forêst street
Project No. D22-1-266
Date: March 28,2022
vtE,
Denver, CO 80207
303-994-5153 Drawn by: TJN
Englneerlng E'au¡t Reviewed by: BTM
VICIN¡TY MAP FIGURE
1
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County Road 264
Rifle, Colorado
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Appendix A
logs of Exploratory Borings
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3885 Forest Street
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CLIENT EN Ensineerinq PROJECT NAME Rifle Compressor Station lmprovements
PROJECT NUMBER D22-1?66 PROJECT LOGATION Rifle, Co
LITHOLOGTC Sy'ltBOtS
(U nified Soil Class ificatio n System)
BEDROCK
CL: USCS Low Plasticity Clay
CL-ML: USCS Low Plasticity Silty Clay
CLS: USCS Low Plasticity Sandy Clay
GP: USCS Poorly-graded Gravel
MLS: USCS Sandy Silt
SM: USCS Silty Sand
SAMPLER SY'I'BOIS
M Grab Sample
2" l.D. Modified California Sampler (MC)
ABBREVIAT'OA'S
LL - LTQUTD LrMrT (%)
Pr - PLASTTC INDEX (%)
MC - MOTSTURE CONTENT (%)
DÐ - DRY DENSTTY (PCF)
NP - NON PLASTIC
FINES- PERCENT PASSING NO. 2OO SIEVE
UCS - UNCONFINED COMPRESSIVE STRENGTH
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SUBSURFACE DIAGRAM"#:PROJECTNI|MRFR t\22-1-26,6PROJECTlt^ ttEPROJECTÞ;a^nôlìamnreccar StalinnCLIENT EN EnoineerinoVIVID Engineering Group, lnc.3885 Forest StreetDenver, CO 80207Telephone: 303-994-51 535,2655,2855,3205,315,3155,2805,310co(EoLrloclodo-oUFoU9ÀfoÉ.oNNNFctqÉfÈ-uNa)3od
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GROUND WATER LEVELS:
AT TIME OF DRILLING --
BORING NUMBER 8.1
PAGE 1 OF 2
CHECKED BY T. Nevin
AI-I ER URILLING --
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PROJECT Stafinn lmnrn¡amanlc^
ltElt Þ¡f,^
AT END OF hÞil I ttllÊ
DRILL¡NG METHOD ODEX
GROUND ELEVATTONIS19 ft_HOLE SIZE 6 inches
CLIENT EN Enqineerinq
DRILLING CONTRACTOR Dakota Drllllns (CfvlE-7s)
LOGGED BY K. Hasan
NOTES
PROJECT LOCATION Rifle, COPROJECT NUMBER D22-1-266
-DATE STARTED 3I1OI22 COMPLETED 3/10/22
VIVID Engineering Group, lnc.
3885 Forest Street
Denver, CO 80207
Telephone: 303-994-5153
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Gravel
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MC 58 6-6
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Swell = 0.5%
when wetted
under 500 psf
MC 34
DD = 114.2 pcf
light brown, slightly moist to moist, medium stiff to stiff
5307
MC 24
15 MC 34
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DD = 107.3 pcf
Compression =
0.6% when
wetted under
DD = 108.1
MC 7-3
MC 3-4
DD = 108.4 pcf
LL=NP
PL=NP
Fines = 37.0olo
= 105.9
light brown, moist, loose
MC 4-5
MC 5,6 DD=1089
MC 4-6
Sandy Silty CLAY, light brown, slightly moist to moist, stiff
(Continued Next Page)
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BORING NUMBER 8.1
PAGE 2 OF 2tit,
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PROJECT NAMECLIENT EN EnOi Rifle ComDressor Station
VIVID Engineering Group, lnc.
3885 Forest Street
Denver, CO 80207
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TESTS
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SHALE, grey and brown, very
Refusal at 53.5 feet
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PROJECT NAME Rifle Compressor Stat¡on lmprovement6
PROJECT NUMBER D22-1-266 PROJECT LOCATTON Rifle, CO
DRILLING CONTRACTOR Dakota Drillinq (CM GROUND WATER LEVELS:
CHEGKED BY T. Nevin AT END OF DRILLING -
BORING NUMBER 8.2
PAGË 1 OF 2
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CLIENT EN Fnoincarina
DRILLING METHOD ODEX
DATE STARTED 3l9l?2
AFTER,tìÞlr r lNê ---
GROUNDELEVATION 5316ft HOLE SIZE 6 inches
LOGGED BY K. Hasan
NOTES
COMPLETED 3I1OI22
VIVID Engineering Group, lnc.
3885 Forest Street
Denver, CO 80207
Telephone: 303-994-5153
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LL=23
PL= 12
Fines = 77.0%
Compression =
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wetted under
1000 psf load
{ r,¡c 4-4
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MC = 13.6%
DD = 115.9 pcf
LL=23
PL= 14
Fines = 55.0%
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Compression =
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15 I n¡c 2-3
I n¡c 2-4
DD = 106.4 pcf
UC = 681
DD = 1'10.9 pcf
Compression =
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DD = 104.8 pcf
LL=23
PL=15
000 load
20 I r,lc 3-3
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DD = 112.5 ncf
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DD = 111.5 pcf
UC = 1847
Gravel
Lean with sand, light brown, slightly moist to moist, medium stiff to stiff
Lean CLAY, light brown, moist, soft to stiff
(Continued Next Page)
PROJECT NAME Rifle Compressor Station lmprovements
PROJECT LOCATION Rifle, CO
tf:
CLIENT FN Fnıi
PROJECT NUMBER D22-1-266
BOR¡NG NUMBER 8.2
PAGE 2 OF 2VIVID Eng¡neering GrouP, lnc.
3885 Forest Street
Denver, CO 80207
Telephone: 303-994-5153
MATERIAL DESCRIPTIONTESTS
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very hard
Refusal at 54.2 feet
SHALE, grey
of borehole at 54.2 feet.
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Geotechnical Laboratory Test Results
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SUMMARY OF LABORATORY RESULTS
PAGE 1 OF 1
CLIENT EN Enoineerino PROJECT NAME Rifle ComDressor Station
PROJECT NUM PROJECT LOCA
Exploration
ID
Sample
Description
Passing
3/4" Sieve
(%\
Passing
lf4 Sieve
('/")
Passing
#200 Sieve
(%)
Liquid
Limit
(LL)
Plastic
Limit
(PL)
Plasticity
lndex
(Pt)
Moisture
Content
(Y"')
Dry
Density
(pcr)
B-1 2.0 SANDY LEAN CLAY(CL)68 24 13 11 11.1
B-1 4.0 11.4 108.4
B-1 9.0 12.9 114.2
B-1 12.0 11.0 1A7.3
B-1 14.0 11.4 108.1
B-1 17.O SILTY SAND(SM)37 NP NP NP 6.4 108.4
B-1 19.0 6.7 105.9
B-1 29.0 8.6 108.9
B-1 39.0 SANDY SILTY CLAY(CL-ML)64 21 15 6 9.6 115.8
B-1 49.0 20.5 105.3
B-2 2.0 LEAN CLAY w¡th SAND(CL)77 23 12 11 9.4 110.4
B-2 7.5 SANDY LEAN CLAY(CL)55 23 14 9 13.6 115.9
B-2 9.0 14.2 115.4
B-2 12.4 8.8 106.4
B-2 14.0 11.5 110.9
B-2 17.0 23 15 I 15.3 104.8
B-2 24.0 14.5 112.5
B-2 27.O 11.3 111.5
B-2 39.0 17.0 109.1
B-2 49.0 SANDY SILT(ML)68 NP NP NP 15.3 108.0
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ATTERBERG LIMITS' RESULTS
CLIENT EN Enoineerino PROJECT NAME Rifle Compressor Stat¡on lmprovements
PROJECT NUMBER D22.1 -266 PROJECT LOCATION Rifle, CO
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BOREHOLE DEPTH LL PL PI Fines Classification
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E B-l 17.0 NP NP NP 37 srLTY SAND(SM)
^B-1 39.0 21 l5 6 64 SANDY S¡LTY CLAY(CL-ML)
*B-2 2.0 23 12 11 77 LEAN CLAY with SAND(CL)
o B-2 7.5 23 14 9 55 SANDY LEAN CLAY(CL)
o B-2 17.0 23 t5 I
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3885 Forest Street
Denver, CO 80207
Telephone: 303-994'5153
U.S. SIEVE OPENING IN INCHES I U.S. SIEVE NUMBERS HYDROMETER
6 4 3 21.5 1314 1416 20 30 40 5060 100140200
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GRAIN SIZE IN MILLIMETERS
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COBBLES
GRAVEL SAND SILT OR CLAY
coarse fine coarse medium fine
LL PL PI Cc CuBOREHOLE DEPTH Classification
24 13 11SANDY LEAN CLAY(CL)o 2.0B-1
NP NP NPsrLTY SAND(SM)a 17.0B-t
21 l5 6A39.0B-l sANDY S|LTY CLAY(CL-ML)
23 12 11LEAN CLAY with SAND(GL)*2.0B-2
92314o7.5B-2 SANDY LEAN CLAY(CL)
D30 D10 %Gravel %Sand %silt o/oClayD100D60BOREHOLE DEPTI-,
68.0o2.0B-l 0.075
37.0a17.0B-1 0.075
64.00.075AB-1 39.0
77.0*2.0B-2 0.075
55.0o7.5B-2 0.075
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3885 Forest Street
Denver, CO 80207
Tclcphonc: 303-994-5153
GRAIN SIZE DISTRIBUTION
CLIENT EN Enıinâ6rinö PROJECT lt
^
ltE lflà Rlâllôñ lññr^rrÂñâñla
U.S. SIEVE OPENING IN INCHES I6 4 3 21.5 13t4 1t23tg 3 4 6
U.S, SIEVE NUMBERS HYDROMETER
14
80
75
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65FI960
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É.uJ 50
=ILF45zt!
P40
t¡JfL
35
30
25
20
't5
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GRAIN SIZE IN MILLIMETERS
0.1 0.01 0.001
COBBLES GRAVEL SAND SILT OR CLAYcoarsefinecoarsemediumfine
I I
BOREHOLE DEPTI-Classification LL PL PI Cc Cu
a B-2 49.0 SANDY SILT(ML)NP NP NP
BOREHOLE DEPTI-D100 D60 D30 D10 %Gravel %Sand % silt o/oC,lay
a B-2 49.0 0.075 68.4
VlVlÐ Engineering ErauP, lnc.
D2t-t-266
tD.:B-1
Description:
%
Swell wett¡
Sandy Lean CIAY L¡ght Brown, moist
Sample Depth (ft)
Name:
No.:/lt
Vi,o
Englæer&ÐErwp
10.01.0
srREss (KsF)
5,0
4.0
3.0
2.O
èR 1.0
t-zU
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JJU
B -r.o
-2.O
-3.0
-4.0
-5.0
+SWELL / SETTLEMENT
Dry Density (pcf)
Mo¡sture Content
Post-Swell Condition
Mo¡sture Content
VIVID Engineering Eraup, lnE.
B-1
Date
tD.:
Descf¡ption:
Yo
@
S¡lty SAND, Light Brown, moist
D21-t-266
RlfleName:
No.:
,/,:
Englneathq Aruup
Sample Depth (ft) 72
10.0
\
\
1.0
srREss (KsF)
0.1
5.0
4.0
3.0
2.0
às 1.0
F-zu
UJF 0.0tsU
J)U3 -r.o
-2.0
-3.0
-4.0
-5.0
-F SWELL / SETTLEMENT
Post-Swell Condition
Mnistrrre content %-
lnitial Condition
Dry Density (pcf)
Moisture Content
VlVlÐ Engíneering Eroup, lnc.
mple Description:
Date
tD.B-2
úVlæerlngElø,p
%
@
Lean CIAY with sand, Lieht Brown,moist
Sample Depth (ft) 2
D2t-7-266
Rifle CoName:
No.:
,/;!
10.01.0
srREss (KsF)
0.1
5.0
4.0
3.0
2.0
èR 1.0
Fzr
UJF 0.0Fu
JJU3 -r.oØ
-2.O
-3.0
-4.0
-5.0
+sWELL/ SETTLEMENT
Dry Density (pcf)
Moisture Content
lnitial
Post-Swell Condition
Moisture Content
VlVlÍI Enqíneering Eroup, Inc.
sandy Lean cLAy, tight Brown, moist Ens¡nøsr'ns ÉrcuF
Date
D21-1-265
,/:tD.:B-2
%
wetti
Description:
Name:
No.:
Sample Depth (ft) 9
5.0
4.0
3.0
2.O
àR 1.0
t-zU
UJr-- 0.0tsg
JJu3 -r.ovl
-2.0
-3.0
-4.0
-5.0
0.1 1.0
srREss (KsF)
10.0
I
+ SWELI / SETTLEMENT
lnitial Cond¡tion
Moisture Content %
Dry Density (pct)
Post-Swell Condition
Moisture content %-
VlVliJ Engineerìng Eraup, lnc.
EnglæErb'ç&wp
Date
ù2t-t-266
/i'/t
V*,otD.B-2
Description:
%
Com @
Namel
No.:
Sample Depth (ft) 74
Sandv Lean CLAY, Lisht Brown, moist
5.0
4.0
3.0
2.O
èR 1.0
t-zU
rJF O.0t-U
JJu3 -r.o
-2.O
-3.0
-4.0
-5.0
10.01.0
srRESs (KSF)
0.1
+SWELL / SÊTTLEMENT
lnítial Condition
Mo¡sture Content
Dry Density {pcf)
Post-Swell Condition
Moisturecontent %-
UNCONFINED COMPRESSION TEST
ASTM D 2166
PROJECT NAME:
PROJECTNO. :
CLIENT NAME:
BORING NO.:
SAMPLE NO.:
DEPTH, FT. :
TEST SPECIMEN NO.:
INITIAL DATA
Avg. Hoight, ln.:
Avg. Diameter, ln.:
UD Ratio:
Moisture Content, %:
(Sample, After test)
Dry Dens¡ty, pcf:
Assumed Specific Gravity:
Saturat¡on, %:
Vo¡d Ratio:
Rlfle Comp Statlon PROJEGT ENG.:
DATE REGEIVED;
DATE TESTED:
TESTED BY:
DATA ENTRY:
DESGRIPTION:
Brown, mo¡st
TN
3t24t2022
3t24t2022
TK
TK
Sandy Lean CLAY, Light
D22-1-268
EN Engineering
B-t
s-3
9ft
3.863
1.920
2.O
12.9
114.2
2.7
73.0
01476
Photo:
Rate of Strain, YolMinutê:1.0
Compressive Strength @ Failure:
Shear Strength @ Failure:
Axial Strain @ Failure,%:
PSF PSI
3072 21
1536 11
3.53.5
lrØ
o.
aooL+,Ø
o
'-u,
ooL
CL
Eoo
3500
3000
2500
2000
1 500
1 000
500
0
å
/
\
tI
{
{
/
/I
I
Stress - Strain Gurve
1505 10
Axial Strain, %
,Æ'
E
'{ghEêtrdgGtoup
PROJECT NAME:
PROJECTNO. :
CLIENT NAME:
BORING NO.:
SAMPLÊ NO,:
DEPTH, FT. :
TEST SPECIMEN NO.:
IN¡TIAL DATA
Avg. Height, ln.:
Avg. Diametêr, ln.:
UD Rat¡o:
Moisture Content, %:
(Sample, After test)
Dry Dens¡ty, pcf:
Assumed Specific Gravity:
Saturat¡on, %:
Void Ratio:
UNCONFINED COMPRESSION TEST
ASTM D 2166
PROJECT ENG.:
DATE RECE¡VED:
DATE TESTED:
TESTED BY:
DATA ENTRY:
3t24t2022
312412022
TK
TK
Silty SAND, Light Brown, moist
Rifle Comp Station TN
D22-1-266
EN Engineering
B-l
s-6
17ft
1
3.913
1.920
2.O
6'4- 10s¿
-------n-31.3
0.554
DESCRIPTION
Photo:
Rate of Strain, %/Minute:1.0
Gompressive Strength @ Failure:
Shear Strength @ Failure:
Axial Strain @ Failure,%:
PSF PSI
1473 10
737 5
1.3 '1.3
lJ.
ØÈ
tñooL+,Ø
o.to
3noL
CL
Eo
C)
1 600
1400
1200
1 000
800
600
400
200
0
À
I I \
I
I
Stress - Strain Gurve
1505 10
Axial Strain, 7o
/,v/,v;;"
EnglneQrlnE grouq
UNCONFINED COMPRESSION TEST
ASTM D 2166
PROJECT NAME:
PROJECTNO. :
GLIENT NAME:
Avg. Height, ln.:
Avg. Diameter, ln.:
UD Ratio:
Moisture Contont, %:
(Sample, After test)
Dry Density, pcf:
Assumed Specific Grav¡ty;
Saturâtion, %:
Void Ratio:
Rlflo CÕmp Statlon
D22-1-266
Elt Ensimerins
PROJECT ENG.:
DATE RECE¡VED:
DATE TESTED:
TESTED BY:
DATA ENTRY:
DESCRIPTION:
Brown, moist
TN
3t24t2022
3t24t2022
TK
TK
Sandy Lean GLAY, Light
BORING NO.:
SAMPLE NO.:
DEPTH, FT, :
TEST SPECIMEN NO.:
B-2
S"l
12ft
1
INITIAL DATA
3.933
1.930
2.O
8.8
106.4
2.7
40.8
0.583
Rate of Strain, %/Minute:1.0
Gompressive Strength @ Failure:
Shear Strength @ Failure:
Axial Strain @ Failure,%:
Photo:
PSF PSI
68r 5
341 2
1.1 '1.1
lr
CN
o-
o
ØoL*,Ø
o
.uotooL
CL
Eoo
800
700
600
500
400
300
200
100
0
I
n\
\
a
I
Stress - Strain Gurve
1505 10
A¡<ial Strain, %
/Êt,
V'í,o
Englnestt!86ra.E
PROJECT NAME:
PROJECTNO. :
CLIENT NAME:
BORING NO.:
SAMPLE NO.:
DEPTH, FT. :
TEST SPEGIMEN NO.:
INITIAL DATA
Avg. Height, ln.:
Avg. Diameter, ln.:
UD Ratio:
Moisture Contenl, %:
(Sample, After test)
Dry Density, pcf:
Assumed Specific Gravity:
Saturation, %:
Void Ratio:
UNCONFINED COMPRESSION TEST
ASTM D 2166
PROJECT ENG.:
DATE RECEIVED:
DATE TESTED:
TESTED BY:
DATA ENTRY:
Rifle Comp Station TN
D22-1-2G6 3t2U2022
EN Engineering 3t24t2022
TK
s-2s{
27Ít
3.990
1.920
2.1
't1.3---_----111s-
----27
59.8-------1.5ñ-
TK
DESCRIPTION:
moist
Photo:
Sandy Lean CLAY. Liqht
Rate of Strain, yolMinute:1.0
Compressive Strength @ Failure
Shear Strength @ Failure:
Axial Strain @ Failure,%:
PSF PSI
'1847 13
924 6
2.32.3
/,Ê'/,V,o
lr(t,
È
aooL*,rn
o
.¿oooL
CL
Eoo
2000
1 800
1 600
1400
1200
1 000
800
600
400
200
0
I
/\,I
I
I
I
{
J
Stress - Strain Gurve
1505 10
Axial Strain, %
Engbreerlngfurup
Appendix C
Analytical Laboratory Test Results
AprilT, 2022
Mvid Engineering, lnc
Attn: Tom Nevin
3885 Forest Street
Denver, CO 80207
Project No.:
Sample lD:
Laboratory No.
\ryELD LABORATORIESO INC'
1527 First Avenue ' Greele% Colorado 80631
Phone: (970) 353-81 l8 ' Fax: (970) 353-t671
www.weldlabs.eom
D22-1-266 - Rifle ComPressor
B-1 0-5'
F-22077-3 Resultsr'3 lo-PointSystem2
pH (sl)
AASHTO T 289-91 (ASTM G51 available for some soil)
Conductivity (mmhos/cm)
Resistivity (ohm-m)
USDA Handbook 60, temperature conected conductivity probe
Minimum Lab ResistivitY (ohm'cm)
Minimum Lab ResistivitY (ohm-m)
via Miller Box, Tinker & Razor SR-2 (AASHTO T 288'12¡4
Redox (mV vs. Ag/AgCD
ASTM G200 (ASTM D1498 if soilis low in moisture)
Free Sulfide (mglkg DMB)
EPA 90308+9034, prescreened with lead acetate paper
Chloride (mg/kg DMB)
AASHTO T 291-94
Sulfate (mg/kg DMB)
AASHTO T 290-95
Sulfate-S (mg/kg DMB)
8.1
4.44
2.25
260
2.6
231
4.2
2331
5't8
173
10
0
NA
0
3.5
o
2
l. NA - Nol Anallzed or Nol Appllcsbls. DMg = Dry Metlor Bas'rs. llþasursments laksn El 25nC.
2. lO.point Conosion system based on: Agpendix A of ANSI/AWWA C105/421.5 Standad "Poþethylene Encas€menl
for Ducülc lron Pipe Syslems." The Cl- poinls based on [Cl-l in 'Nature: Scienlilic Repofls Volume 7. Articl€ number: 6865 (2017f
Sutfate is penalÞsd st hsf ths rate of chloride: A A. Sagttés ot. al. (hltpsrrrosap.ntl.bts.govMew/dol/17493)
3. pH, Conduclivity. snd Redox are generally road on a 1:1 soi[wat€] mlxlure if the soll ls dry.
4.+Elsc{rode used unþss 2+þctrode melhod ie ßquested.
tl -7-rÅ
0ate
Sampling procctlurcs can alfr:ct tfig value of analyticll results - c¡¡slontcrs arc ¡dviscrl to use appropriatc sampling prctocol to cnslrc stmplos
are truly rcpn:scntativc of the bulk samplc.
Appendix D
Site Photos
DRILLING BORING 8.1, LOOKING SOUTH
BORING 8.2, LOOKING EAST
Project No. D22-1-266
l, ururoEnsineering Group,,/ / ssgs Forest stroet Date: March 28,2022
vtÐ
Denver, CO 80207
303.994-51 53 Drawn by: TJN
Engineerlng ErouF Reviewed by: BTM
SITE PHOTOS FIGURE
D-1Rifle Compressor Station lmprovements
County Road 264
Rifle, Colorado
Appendix E
lmportant lnformation About This Geotechnical Engineering Report
Rli I tiT int illII
chnical-[ll[ineel'inU Rerul'lIBûen
The Geoprofessional Business Assoeiation (GBA)
has prepared this advisory to help you - assumedly
a client representative - interpret and apply this
geotechnical-engineering report as effectively
as possible. ln that way, clients can benefit from
a lowered exposure to the subsurface problems
that, for decades, have been a principal cause of
construction delays, cost overruns, claims, and
disputes. lf you have questions or want more
information about any of the issues discussed below,
contact your GBA-member geotechnical engineer'
Active involvement in the Geoprofessional Business
Association exposes geotechnical engineers to a
wide array of risk-eonfrontation techniques that can
be of genuine benefit for everyone involved with a
construction project.
Geotechnical-Engineering Services Are Performed for
Specific Purposes, Persons, and Projects
Geotechnical engineers structure their services to meet the specific
needs oftheir clients. A geotechnical-engineering study conducted
for a given civil engineer will not likely meet the needs of a civil-
works constructor or even a different civil engineer. Because each
geotechnical-engineering study is unique, each geotechnical-
èngineering report is unique, prepared soleþ for the client. Those who
rely on a geotechnical-engineering report Preparcd for a diferent clíent
can be seriously misled. No one except authorized client representatives
should rely on this geotechnical-engineering report without frrst
conferring with the geotechnical engineer who prepared it. And no one
- not even you - should apply thís report for any purpose or project excePt
the one originally contemplated.
Read this Report in Full
Costly problems have occur¡ed because those relying on a geotechnical-
engineering report did not read it in its entirety. Do not rely on an
executive summary. Do not read selected elements only' Read this report
infull.
You Need to lnform Your Geotechnical Engineer
about Change
Your geotechnical engineer considered unique, project-specifrc factors
when designing the study behind this report and developing the
confirmation-dependent recommendations the report conveys. A few
typical factors include:
. the client's goals, objectives, budget, schedule, and
risk-management preferences;
. the general nature ofthe structure involved, its size,
configuration, and performance criteria;
. the structure's location and orientation on the site; and
. other planned or existing site improvements, such as
retaining walls, access roads, parking lots, and
underground utilities.
Tlryical changes that could erode the reliability ofthis report include
those that affect:
. the sitet size or shape;. the function ofthe proposed structure, as when it's
changed from a parkng garage to an office building, or
from a light-industrial plant to a refrigerated warehouse;
. the elevation, configuration, location, orientation, or
weight ofthe proposed structure;
. the composition of the design team; or
. project ownership.
As a general rule, always inform your geotechnical engineer ofproject
changes - even mino¡ ones - and request an assessment oftheir
impact. The geotechnical engineer who prepared this report cannot accept
responsibility or liability for problems that arise because the geotechnical
engineer was not informed about developments the engineer otherwise
wouldhave considered.
This Report May Not Be Reliable
Do not rely on this report if your geotechnical engineer prêpared it:
. for a different client;
. for a different project;
. for a different site (that may or may not include all or a
portion ofthe original site); or
. before important events occurred at the site or adjacent
to it; e.g., man-made events like construction or
environmental remediation, or natural events like floods,
droughts, earthquakes, or groundwater fluctuations.
Note, too, that it could be unwise to rely on a geotechnical-engineering
report whose reliability may have been affected by the passage of time,
because offactors like changed subsurface conditions; new or modified
codes, standards, or regulations; or new techniques or tools. Ifolr
geotechnicøl engineer høs not indicøted an "apply-by" date on the report,
ask what it should be, and, in general, if you are the least bit uncertain
about the continued reliability ofthis report, contact your geotechnical
engineer before applying it. A minor amount ofadditional testing or
analysis - if any is required at all - could prevent major problems.
Most of the "Findings" Related in This Report Are
Professional Opinions
Before construction begins, geotechnical engineers explore a site's
subsurface through various sampling and testing procedures.
Geotechnical engifleers can observe actual subsurface conditions only at
those specifc locations where sampling and testing were perþrmed' The
data derived from that sampling and testing were reviewed by your
geotechnical engineer, who then applied professional judgment to
form opinions about subsurface conditions throughout the site. Actual
sitewide-subsurface conditions may differ - maþe signiûcantly - from
those indicated in this report. Confront that risk by retaining your
geotechnical engineer to serve on the design team from project start to
project frnish, so the individual can provide informed guidance quickl¡
whenever needed.
Subsurface problems are a principal cause of construction delays, cost overruns, claims, and disputes.
While you cannot eliminate all such risks, you can manage them. The following information is provided to help
This Report's Recommendations Are
Gonfirmation-Dependent
The recommendations included in this report - including any options
or alternatives - arc confirmation-dependent. In other words, the.y are
notfnal,because the geotechnical engineer who developed them relied
hcavily on judgmont and opinion to do oo. Your gcotccluricol cngitrccr
can ûnalize the recommendations only affer observing actual subsurþce
conditions revealed cluri n g constnrction. If th rorr gh nhservati on yor r r
geotechnical engineer confirms that the conditiolts ¿ssurled [o cdsL
actualþ do exist, the recommendations can be relied upon, assuming
no other changes have occurred. The geotechnical engineer who prepared
this report cannot assume responsibility or liability for confirmntion-
dependent recommendations if you fail to retaln that engtneer to perform
construction ob ser vatio n,
This Report Could Be Misinterpreted
Other design professionals' misinterpretation of geotechnical-
engineering reports has resulted in costly problems. Confront that risk
by having your geotechnical engineer serve as a full-time member of the
design team, to:. confer with other design-team members,. help develop speciflcations,. review pertinent elements ofother design professionals'
plans and speciûcations, and. be on hand quickly whenever geotechnical-engineering
guidance is needed.
You should also confront the risk ofconstructors misinterpreting this
report. Do so by retaining your geotechnical engineer to participate in
prebid and preconstruction conferences and to perform construction
observation.
Give Constructors a Complete Report and Gu¡dance
Some owners and design professionals mistakenly believe they can shift
unanticipated-subsurface-conditions liabiliÇ to constructors by limiting
the information they provide for bid preparation. To help prevent
the costly, contentious problems this practice has caused, include the
complete geotechnical-engineering report, along with any attachments
or appendices, with your contract documents, but be certain to note
consPicuously that youve included the materiøl for informational .
purposes only. To avoid misunderstanding, you may also want to note
that "informational purposes" means constructors have no right to rely
on the interpretations, opinions, conclusions, or recommendations in
the report, but they may rely on the factual data relative to the specific
times, locations, and depthsielevations referenced. Be certain that
constructors know they may learn about specific project requirements,
including options selected from the report, onlyfrom the design
drawings and specifications. Remind constructors that they may
perform their own studies if they want to, and be sure to allow enough
úize to permit them to do so. Only then might you be in a position
to give ct-lrstructt¡¡s the iufun¡raLiu¡r availal¡lc tu yuu, while ret¡uiring
them to at least share some of the financial responsibilities stemming
from unanticipated conditions. Conducting prebid and prcconstruction
r:r-rnferenceç cirn irll,r tre virlurrLrle irr thir rerpect.
Reacl Respons¡b¡l¡ty Provisions Closely
Some client representatives, destgn professionals, and constructors do
not realize that geotechnical engineering is far less exact than other
engineering disciplines. That lack ofunderstanding has nurtured
unrealistic expectations that have resulted in disappointments, delays,
cost overruns, claims, and disputes. To confront that risk, geotechnical
engineers commonly include explanatory provisions in their reports.
Sometimes labeled "limitations," many of these provisions indicate
where geotechnical engineers' responsibilities begin and end, to help
others recognize their own responsibilities and risks. Read these
provisions closeþ. Ask questions. Your geotechnical engineer should
respond fully and frankly.
Geoenvironmental Goncerns Are Not Govered
The personnel, equipment, and techniques used to perform an
environmental study - e.g., a "phase-one" or "phase-two" environmental
site assessment - differ signiñcantly from those used to perform
a geotechnical-engineering study. For that reason, a geotechnical-
engineering report does not usually relate any environmental findings,
conclusions, or recommendations; e.g., about the likelihood of
encountering underground storage tanks or regulated contaminants.
Unanticipated subsurface environmental problems have led to project
failures. Ifyou have not yet obtained your own environmental
intbrmation, ask your geotechnical consultant fbr risk-management
guidance. As a general rule, do not rely on an environmental report
prepared for ø diferent client, site, or project, or that ís more than six
months old.
Obtain Professional Assistance to Deal w¡th Mo¡sture
lnfiltration and Mold
While your geotechnical engineer may have addressed groundwateç
water infiltration, or similar issues in this report, none of the engineer's
services were designed, conducted, or intended to prevent uncontrolled
migration of moisture - including wâter vâpor - from the soil through
building slabs and walls and into the building interio¡, where it can
cause mold growth and material-performance deficiencies. Accordingly,
prop et implementøtion of the geotechnical engineer's reco mmendation s
wíIl not of ¡ßelÍ be suficient to prevent moìsture ínfiltration, Confront
the risk of moisture infiltration by including building-envelope or mold
specialists on the design Tearn. Geotechnlcøl engineers are not buildíng-
entelope or mold specialísts.
GEOPROFESSIONAL
BUSINESSI assoctATtoN
Telephone: 30L I 565 -27 33
e- m ail : i nfo@geoprofessional. org www. geoprofessional. org
CoPyright 2016 by Geoprofestional Busineô6 A66ociation (GBA). Duplication, reproduction, or copying ofthis documcnt, in wholc or in pùt, by any mcms whatsocvcr, is strictly
of GBA, and only for purposes of scholarþ resèarch or book review Only members of GBA may use this docment or its wording as a complement to or as m element of a report of my
kind. Ary other firm, individual, or other entity that so uses this docment without being a GBA member could be committing negligent