PRELIMINARY GEOTECHNICAL INVESTIGATION
UCCS PARKING GARAGE
STANTON STREET AND AUSTIN BLUFFS PARKWAY
COLORADO SPRINGS, COLORADO
Prepared for:
UNIVERSITY OF COLORADO AT COLORADO SPRINGS
Facilities Services
1420 Austin Bluffs Parkway
Colorado Springs, Colorado 80918
Attention: Mr. Gary Reynolds
CTL|T Project No. CS17987-115
October 29, 2012
5240 Mark Dabling Blvd | Colorado Springs, Colorado 80918 | Telephone: 719-528-8300 Fax: 719-528-5362
TABLE OF CONTENTS
SCOPE..................................................................................................................................... 1
SUMMARY............................................................................................................................... 1
SITE CONDITIONS.................................................................................................................. 2
PROPOSED DEVELOPMENT ................................................................................................ 4
SITE GEOLOGY ...................................................................................................................... 4
FIELD INVESTIGATION.......................................................................................................... 5
SUBSURFACE CONDITIONS ................................................................................................ 5
Existing Fill ....................................................................................................................... 6
Natural Sand ..................................................................................................................... 6
Bedrock ............................................................................................................................. 6
Groundwater..................................................................................................................... 7
Seismicity.......................................................................................................................... 7
SITE PREPARATIN AND UTILITIES ...................................................................................... 7
CONSTRUCTION CONSIDERATIONS ................................................................................ 10
Foundations.................................................................................................................... 10
Slabs-on-Grade .............................................................................................................. 10
Below-Grade Construction ........................................................................................... 11
Pavements ...................................................................................................................... 11
CONCRETE ........................................................................................................................... 12
SURFACE DRAINAGE.......................................................................................................... 12
CONSTRUCTION OBSERVATIONS .................................................................................... 12
GEOTECHNICAL RISK......................................................................................................... 13
LIMITATIONS ........................................................................................................................ 13
FIG. 1 – LOCATION OF EXPLORATORY BORINGS
FIG. 2 – SUMMARY LOGS OF EXPLORATORY BORINGS
APPENDIX A – SWELL CONSOLIDATION TEST RESULTS
TABLE A-1 – SUMMARY OF LABORATORY TESTING
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SCOPE
This report presents the results of our Preliminary Geotechnical Investigation for
the proposed Stanton Street Parking Garage to be constructed on the campus of the
University of Colorado at Colorado Springs. This report includes a description of
subsurface and groundwater conditions found in our borings and our opinions regarding
the potential influence of these conditions on site development and structure
construction. The report also includes preliminary geotechnical design and construction
criteria for installation of buried utilities and site grading, and concepts for structure
foundations, slabs-on-grade, and pavement sections. We believe this study was
completed in general conformance with our proposal (CS-12-0134) dated September 12,
2012.
No preliminary documents or construction plans were available for the proposed
parking garage, at the time of this report. Our understanding of the project is based on
the owner’s verbal description of the location and type of proposed construction. The
report was prepared based on conditions interpreted from conditions found in our
exploratory borings, results of laboratory tests, engineering analysis, and our experience.
As the project documents become more definitive, we should review the plans to
formulate specific design and construction recommendations. Evaluation of the site for
the possible presence of potentially hazardous materials (Environmental Site
Assessment) is beyond the scope of this investigation.
The following section summarizes our evaluation. A more complete description of
the conditions found, our interpretations, and our recommendations are included in the
report.
SUMMARY
1.
Depending on the actual size and location of the planned structure on the
investigated parcel, a significant amount of site preparation and fill
placement may be necessary to achieve the desired building pad elevation.
2.
Subsurface conditions encountered in our exploratory borings drilled
within the vicinity of the planned parking garage consisted of about 10 to
over 25 feet of natural sand underlain by claystone or sandstone bedrock.
A layer of existing fill material, 3 to 5 feet thick, was encountered at the
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ground surface in two of the borings. Samples of the natural, very clayey
sand, sandstone, and claystone exhibited low to moderate measured swell
values when wetted.
3.
At the time of drilling, groundwater was not encountered in the exploratory
borings. When water levels were checked again two days after the
completion of drilling operations, the borings were again found to be dry.
4.
We believe grading and utility installation can be accomplished using
conventional heavy-duty equipment.
5.
To reduce the risk of excessive total and differential movements of
potentially heavily-loaded foundation columns underlain by a possibly
widely varying thickness of grading fill, natural soils and bedrock, we
recommend the garage structure be planned considering a drilled pier
foundation bottomed in the underlying bedrock.
6.
New moisture conditioned and densely compacted grading fill and the onsite, natural soils will likely provide good support characteristics for lightly
loaded, at-grade garage slabs. Slabs bearing on or near expansive
claystone may experience movement and associated damage. Where
claystone bedrock is present near the slab elevation, subexcavation of the
claystone and replacement with moisture conditioned fill will likely be an
appropriate method to mitigate the effects of the expansive materials. The
risk of poor slab performance cannot be fully evaluated until plans and atgrade slab elevations are defined.
7.
For planning purposes, pavement thicknesses for full-depth asphalt
sections for access driveways to the garage in the range of 5 to 6 inches
are anticipated. Concrete pavement, 5 to 6 inches thick, is expected in the
lowest parking level.
8.
Surface drainage should be designed for rapid runoff of water away from
the proposed parking garage. Water should not be allowed to pond
adjacent to the structure or over exterior slabs or pavements.
SITE CONDITIONS
The site of the proposed Stanton Street Parking Garage is located north of the
intersection of Stanton Street and Mountain Lion Way on the campus of the University of
Colorado at Colorado Springs. The parcel is situated on the face of a generally northwestfacing slope. The ground surface slopes downward to the northwest at grades estimated
to be between about 10 and 15 percent, with locally near-vertical banks in the vicinity of
what appears to be a detention basin the northwest portion of the property. A concrete
vault that contains a storm drain outlet and manhole is situated along the southern edge
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of the detention basin. What appears to be a fill wedge, pushed out from the west side of
Stanton Street, is present in the northeast corner of the site. The western side of the fill
wedge slopes downward to the west and northwest at a grade estimated to be about 20
to 25 percent.
Two existing dirt roads are present along the northern edge of the site and in the
central portion of the property. The site has apparently been used extensively in the past
as a dumping area for a variety of materials. Scattered piles of dumped soil, construction
debris (mostly concrete), telephone poles, and organic materials are present throughout
much of the site. Overhead electric power lines form the western boundary of the parcel.
Vegetation on the property consists of grasses, weeds, yucca, scrub oak, a few pine
trees, and scattered deciduous bushes and trees. Some of the main features of the site
are presented in Fig. 1. Photograph Nos. 1 and 2 depict the parcel in its current condition.
Photo No. 1: Northeast corner of the site looking west from Stanton Street.
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Photo No. 2: Southwest corner of the site looking north from Stanton Street.
PROPOSED DEVELOPMENT
We understand the proposed parking garage is in the preliminary conceptual
planning stage. We anticipate the garage will be a cast-in-place and/or pre-cast concrete,
multi-level structure. Concrete slabs are anticipated in the at-grade portions of the
garage. Foundation loads are expected to be moderate to high. We anticipate paved
driveways will provide access to the garage from Stanton Street. We understand an
artificial playing surface is planned on the top level of the garage.
SITE GEOLOGY
Published geologic mapping (“Geologic Map of the Pikeview Quadrangle, El Paso
County, Colorado,” Jon P. Thorson, Christopher J. Carroll and Mathew L. Morgan,
Colorado Geological Survey, 2001) indicates the site is underlain locally by alluvial
deposits (Qfo). The upper member of the Laramie Formation (Klu) comprises the
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underlying bedrock found beneath the near-surface soils. Conditions encountered in our
borings generally confirm the mapping. Our borings and site observations suggest manmade fill of varying thickness has been placed at several locations across the site.
FIELD INVESTIGATION
Our field investigation included drilling five exploratory borings at the general
location of the proposed garage, as outlined by personnel from UCCS. The approximate
locations of the borings are shown in Fig. 1. Exiting topography and the presence of
dumped materials across much of the site limited the possible locations where the
borings could be drilled. The borings were advanced to depths of 25 to 35 feet using 4inch diameter, continuous-flight auger and a truck-mounted drill rig. Drilling was
observed by our field representative who logged the conditions found in the borings and
obtained samples. Graphical logs of the conditions encountered in the borings, the
results of field penetration resistance tests, and laboratory test data are presented in Fig.
2. Swell-consolidation test results are presented in Appendix A. Laboratory test data are
summarized in Table A-1.
Soil and bedrock samples obtained during this study were returned to our
laboratory and visually classified. Laboratory testing was then assigned to representative
samples. Testing included moisture content and dry density, swell-consolidation, sieve
analysis, and water-soluble sulfate content tests. To evaluate potential heave, the swell
test samples were wetted under applied pressures that approximated the overburden
pressure (the weight of overlying soil).
SUBSURFACE CONDITIONS
Subsurface conditions encountered in our exploratory borings drilled within the
vicinity of the planned parking garage consisted predominantly of natural sand underlain
by claystone or sandstone bedrock. A layer of existing fill material was encountered at
the ground surface in two of the borings. The pertinent engineering characteristics of the
soils and bedrock encountered are discussed in the following paragraphs.
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Existing Fill
A layer of existing fill, about 3 to 5 feet thick, was encountered at the ground
surface in two of the borings. The fill consisted of clayey sandy. The fill was loose to
medium dense based on the results of field penetration resistance testing and our
observations during drilling operations. The fill appeared to have been randomly dumped
at the site over a significant period of time. What appears to be a fill wedge, estimated to
be 10 to 15 feet thick, was observed along the eastern edge of the parcel, adjacent to
Stanton Street. We doubt any documentation exists regarding the placement of the fill
material, such as the results of field density testing, and so the fill must be considered to
be of suspect quality and unsuitable to underlie the proposed structure, in its current
condition. If free from deleterious substances, such as construction debris and organics,
some of the material may be suitable for re-use as new fill within the planned
development. The suitability of the existing fill for re-use should occur at the time of
construction.
Natural Sand
About 10 to over 25 feet of natural, silty or clayey to very clayey sand was
encountered at the ground surface or beneath the existing fill in each of the borings.
Occasional layers of very sandy clay were found to be interbedded with the clayey to very
clayey sand. The sand was medium dense to dense based on the results of field
penetration resistance tests. A sample of the clayey sand tested in our laboratory
exhibited a low measured swell value of 0.2 percent when wetted under estimated
overburden pressure. Five samples of the sand contained 14 to 38 percent clay and siltsize particles (passing the No. 200 sieve). Our experience indicates the sands are
typically non-expansive or exhibit low measured swell values when wetted.
Bedrock
Sandy to very sandy claystone bedrock and silty to clayey sandstone were found
in four of the borings drilled at the site, beneath the natural soils, at depths of 10 to 19
feet below the existing ground surface. Claystone appeared to be the predominant
bedrock material. Field penetration resistance test results indicated the bedrock was
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medium hard to very hard. Three samples of the claystone tested in our laboratory
exhibited measured swell values of 0.2 to 1.8 percent when wetted under overburden
pressure, which is indicative of slightly to moderately expansive material. A sample of the
clayey sandstone exhibited a measured swell of 0.1 percent when wetted. The sandstone
is typically non-expansive or exhibits low measured swell values when wetted.
Groundwater
At the time of drilling, groundwater was not encountered in the exploratory
borings. When water levels were checked again two days after the completion of drilling
operations, the borings were again found to be dry. Our experience indicates
groundwater can occur in different forms below this site. Water can be found in the
fissures within the bedrock. A “perched” groundwater table can also form at the
interface between the overlying granular materials and underlying bedrock. The
occurrence of groundwater, the volume, and elevation will fluctuate in response to
seasonal precipitation variations, surface drainage, and landscaping irrigation.
Seismicity
This area, like most of central Colorado, is subject to a degree of seismic activity.
We believe the soils and bedrock on the site classify as Site Class C (dense soil and soft
rock) according to the 2009 International Building Code (2009 IBC). A geophysical study
is required to evaluate the shear wave velocity (V100) profile at the site to potentially
allow for an upgrade to Site Class B. Our firm can provide a site-specific geophysical
seismic study using the ReMi micro-tremor, surface method, if desired.
SITE PREPARATION AND UTILITIES
No grading plans were available for our review during the preparation of this
study. Based on the existing site topography, we anticipate a significant amount of site
preparation work will be needed to achieve the desired building pad elevation and grades
within the any access driveways. The amount and complexity of the site preparation work
will be dependent on the actual location of the structure on the parcel, as well as the size
and configuration (number of levels, extent of below-grade construction, etc.) of the
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garage. We anticipate some deep fills (15 to 20 feet or more) may be necessary, unless
the structure steps down the hillside to accommodate the existing slope of the ground
surface. For planning purposes, permanent cut and fill slopes should be no steeper than
3:1 (horizontal to vertical). Our office should be contacted to review the site grading plans
once they are prepared.
Prior to grading fill placement, surficial stockpiles of construction debris, organic
materials, and vegetation should be stripped away from the ground surface and removed
from the site. Organic topsoil can be stockpiled for later use in landscaped areas.
Existing fill encountered on the site should be excavated to expose the underlying
natural soils. We anticipate a thick layer of existing fill may be present along the eastern
edge of the site, adjacent to Stanton Road. Existing fill materials should be observed by
our representative to determine if the soils are suitable for incorporation into the planned
site grading.
All remnants of the concrete structures and backfill materials associated with the
existing detention basins located in the northwest corner of the property, that impact the
location of the planned garage should be removed from the site before grading of the
property can begin. All organics and soft soils should be removed from the bottom of the
basins to expose firm, natural soils, prior to fill placement.
Our experience suggests a subsurface drain system should be constructed in the
bottom of the existing detention basins, prior to placement of grading fill materials. The
drain will provide an exit point for surficial runoff that penetrates into the backfill soils
and that may otherwise pond in the bottom of the basins. For planning purposes, we
anticipate the drain will consist of washed concrete aggregate wrapped in a non-woven,
geotextile fabric. The location of the drain can be established once a grading plan has
been developed and the position of the parking garage has been established.
Fill materials within the garage footprint should consist of the on-site sands and
sandstone. Sandstone placed as grading fill should be mechanically broken down into
particles of less than 2 inches in diameter. Expansive claystone bedrock should be
placed as fill outside of the planned building footprint as much as possible or be
removed from the site. The granular grading fill should be moisture conditioned to within
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2 percent of optimum moisture content and compacted in thin lifts to at least 95 percent
of maximum modified Proctor dry density (ASTM D 1557). Sandy clays and claystone
placed as fill should be moisture conditioned to between 1 and 4 percent above optimum
moisture content and compacted to at least 95 percent of maximum standard Proctor dry
density (ASTM D 698). The placement and compaction of the grading fill should be
observed and tested by a representative of our office during construction.
Where the existing ground surface exists at a slope ratio of 5:1 (horizontal to
vertical) or steeper, benches should be cut into the hillside, prior to the placement of fill.
The benches should be at least 10 feet in width or one and a half times the width of the
compaction equipment, whichever is greater. The vertical distance between benches
should not exceed 5 feet.
Our borings suggest the on-site soils and bedrock can be excavated using
conventional, heavy-duty equipment. The grading fill and natural soils will likely cave into
unsupported, near-vertical utility trench excavations. Based on the Occupational Safety
and Health Administration (OSHA) criteria governing excavations, the grading fills and
natural soils will probably classify as Type C soils. The bedrock will probably classify as
Type B soil. Temporary excavations in Type B and Type C materials require a maximum
slope inclination of 1:1 and 1.5:1 (horizontal to vertical), respectively, unless the
excavation is shored or braced. Should groundwater seepage occur, flatter slopes may
be necessary. The contractor’s competent person should evaluate the soils at the time of
excavation and determine appropriate safety measures.
We recommend clayey utility trench backfill be placed in thin, loose lifts, moisture
conditioned to within 2 percent of optimum moisture content, and compacted to at least
95 percent of maximum standard Proctor dry density (ASTM D 698). Granular trench
backfill should be moisture conditioned to within 2 percent of optimum moisture content
and compacted in thin lifts to at least 95 percent of maximum modified Proctor dry
density (ASTM D 1557). Personnel from our firm should periodically observe utility trench
backfill placement and test the density of the backfill materials during construction.
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CONSTRUCTION CONSIDERATIONS
Our preliminary opinions regarding foundations, slabs-on-grade, below-grade
construction, and pavements are presented below for the anticipated construction. Once
plans for the parking garage become more defined, our office should be contacted to
provide specific design criteria and construction recommendations.
Foundations
Based on our understanding of the planned construction and data from our
exploratory borings, subsurface conditions beneath the proposed parking garage could
possibly consist of potentially widely varying thicknesses of grading fill, natural sand and
clay soils, and claystone and sandstone bedrock. To reduce the risk of excessive total
and differential movements of potentially heavily-loaded foundation walls, we
recommend the garage be planned considering a drilled pier foundation bottomed in the
underlying bedrock. For planning purposes, we anticipate a maximum allowable end
pressure of 25,000 to 35,000 psf and an allowable skin friction of 2,500 to 3,500 psf for the
portion of pier in comparatively unweathered bedrock will be appropriate for preliminary
pier sizing. We anticipate a minimum deadload pressure of 10,000 to 15,000 psf will be
appropriate for initial design. The presence of potentially caving sands at the site may
require the use of temporary casing to install some of the drilled piers. Our office should
provide site-specific foundation recommendations and design criteria for the planned
structure after site grading plans have been prepared and the building location and
lowest floor elevation have been established.
Slabs-on-Grade
We expect the lowest level of the parking garage will include a concrete slab-ongrade. We judge the risk of poor slab performance will likely be low where new, sandy to
clayey, moisture conditioned and densely compacted grading fill, natural sand, and/or
sandstone are present at or near slab elevations. Should claystone bedrock be
encountered at or near the slab elevation, subexcavation of the claystone and
replacement with moisture conditioned granular fill will likely be an appropriate method
to mitigate the effects of the expansive material. The risks associated with poor slab-onUNIVERSITY OF COLORADO AT COLORADO SPRINGS
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grade performance cannot be evaluated fully until the plans become better defined and
floor slab elevations are established.
Below-Grade Construction
We anticipate portions of the proposed parking garage will be constructed below
exterior grades. The foundation walls will be subjected to lateral earth loads that are
dependent on the height of the wall, soil type, and backfill configuration. For backfill
materials that consist of the on-site, silty to clayey sands and walls that are not free to
rotate, such as foundation walls, we recommend the walls be designed to resist “at-rest”
earth pressures. We recommend design for the “at-rest” earth pressure condition using
an equivalent fluid density of at least 60 pcf. Claystone should not be used as wall
backfill. For planning purposes, foundation drain installation should be anticipated
around all habitable, below-grade construction within the project site, with the possible
exception of non-habitable areas that can be constructed as water-tight structures, such
as elevator pits.
Pavements
Pavement subgrade soils across the site will likely consist of new, sandy to clayey
grading fills and natural, silty to clayey sands and sandy to very sandy clay. We anticipate
the grading fills and natural sands will generally provide good subgrade support
characteristics for pavement systems. The natural clay will provide comparatively poor
pavement support qualities. Where granular subgrade soils are encountered, pavement
thicknesses for full-depth asphalt concrete sections for access driveways in the range of
4 to 6 inches are likely. Pavement thicknesses for full-depth asphalt concrete sections in
areas where clay is the predominant subgrade material will likely be on the order of 1 to 2
inches thicker.
The concrete pavement anticipated in the lowest level of the parking garage is
expected to be on the order of 5 to 6 inches thick. When possible during grading, sands
should be placed in the upper 2 feet of the subgrade in pavement areas to reduce the
required section thickness. Final pavement section recommendations can be provided
once site development and grading plans are prepared.
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CONCRETE
Concrete in contact with soils can be subject to sulfate attack. We measured the
soluble sulfate concentration in one sample from this site at less than 0.1 percent. Sulfate
concentrations less than 0.1 percent indicate Class 0 exposure to sulfate attack for
concrete in contact with the subsoils, according to ACI 201.2R-01, as published in the
2008 American Concrete Institute (ACI) Manual of Concrete Practice. For this level of
sulfate concentration, the ACI indicates Type I/II cement can be used for concrete in
contact with the subsoils. In our experience, superficial damage may occur to the
exposed surfaces of highly permeable concrete, even though sulfate levels are relatively
low. To control this risk and to resist freeze-thaw deterioration, the water-to-cementitious
material ratio should not exceed 0.50 for concrete in contact with soils that are likely to
stay moist due to surface drainage or high water tables. Concrete subjected to freezethaw cycles should be air entrained.
SURFACE DRAINAGE
The performance of this project will be influenced by surface drainage. When
developing an overall drainage plan, consideration should be given to drainage around
the proposed structure and away from paved areas. Drainage should be planned such
that surface runoff is directed away from foundations and is not allowed to pond adjacent
to the parking garage or over pavements. We recommend slopes of at least 6 inches in
the first 10 feet for the area surrounding the structure, where possible. Roof downspouts
and other water collection systems should discharge well beyond the limits of all backfill
around the structure. Proper control of surface runoff is also important to prevent the
erosion of surface soils. Sheet flow should not be directed over unprotected slopes.
Water should not be allowed to pond at the crest of slopes. Permanent slopes should be
seeded or mulched to reduce erosion. Special attention should be paid to compact soils
behind the curb and gutter sections adjacent to streets and in utility trenches.
CONSTRUCTION OBSERVATIONS
We recommend that CTL | Thompson, Inc. provide observation and testing
services during construction to allow us the opportunity to verify whether soil conditions
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are consistent with those found during our investigation. If others perform these
observations, they must accept responsibility to judge whether the recommendations in
this report remain appropriate.
GEOTECHNICAL RISK
The concept of risk is an important aspect with any geotechnical evaluation
primarily because the methods used to develop geotechnical recommendations do not
comprise an exact science. We never have complete knowledge of subsurface
conditions. Our analysis must be tempered with engineering judgment and experience.
Therefore, the recommendations presented in any geotechnical evaluation should not be
considered risk-free. Our preliminary recommendations represent our judgment of those
measures that are necessary to increase the chances that the structure will perform
satisfactorily. It is critical that all recommendations in this report are followed during
design and construction.
LIMITATIONS
Plans for the proposed building were in the preliminary conceptual phase at the
time of this report. The recommendations presented should be considered to be
preliminary. Once the plans become better defined, our firm should be contacted to
formulate geotechnical design criteria and construction recommendations.
Our borings were located to obtain a reasonably accurate indication of subsurface
foundation conditions. The borings are representative of conditions encountered at the
exact boring location only. Variations in subsurface conditions not indicated by the
borings are possible. We recommend a representative of our office observe the
completed foundation excavation. Representatives of our firm should be present during
construction to perform construction observation and materials testing services.
We believe this investigation was conducted with that level of skill and care
normally used by geotechnical engineers practicing in this area at this time. No warranty,
express or implied, is made. If we can be of further service in discussing the contents of
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APPENDIX A
SWELL CONSOLIDATION TEST RESULTS
TABLE A-1 – SUMMARY OF LABORATORY TESTING
UNIVERSITY OF COLORADO AT COLORADO SPRINGS
STANTON STREET PARKING GARAGE
CTL|T PROJECT NO. CS17987-115
S:\CS17500-17999\CS17987.000\115\2. Reports\CS17987-115-R1.doc
7
6
EXPANSION UNDER CONSTANT
PRESSURE DUE TO WETTING
5
4
3
2
1
0
-1
-2
COMPRESSION % EXPANSION
-3
-4
-5
-6
-7
-8
0.1
1.0
10
100
APPLIED PRESSURE - KSF
CLAYSTONE, SANDY
TH-2 AT 24 FEET
UNIVERSITY OF COLORADO AT COLORADO SPRINGS
STANTON STREET PARKING GARAGE
CTL|T PROJECT NO. CS17987-115
S:\CS17500-17999\CS17987.000\115\2. REPORTS\CS17987-115_SWELL.XLS
DRY UNIT WEIGHT=
MOISTURE CONTENT=
112
18.7
PCF
%
Swell Consolidation
Test Results
FIG. A-1
3
EXPANSION UNDER CONSTANT
PRESSURE DUE TO WETTING
2
COMPRESSION % EXPANSION
1
0
-1
-2
-3
-4
0.1
APPLIED PRESSURE - KSF
1.0
CLAYSTONE, WEATHERED
TH-3 AT 14 FEET
100
10
DRY UNIT WEIGHT=
MOISTURE CONTENT=
101
24.4
PCF
%
3
EXPANSION UNDER CONSTANT
PRESSURE DUE TO WETTING
2
COMPRESSION % EXPANSION
1
0
-1
-2
-3
-4
0.1
APPLIED PRESSURE - KSF
1.0
CLAYSTONE, VERY SANDY
TH-3 AT 24 FEET
UNIVERSITY OF COLORADO AT COLORADO SPRINGS
STANTON STREET PARKING GARAGE
CTL|T PROJECT NO. CS17987-115
S:\CS17500-17999\CS17987.000\115\2. REPORTS\CS17987-115_SWELL.XLS
10
DRY UNIT WEIGHT=
MOISTURE CONTENT=
100
112
16.3
PCF
%
Swell Consolidation
Test Results
FIG. A-2
3
EXPANSION UNDER CONSTANT
PRESSURE DUE TO WETTING
2
COMPRESSION % EXPANSION
1
0
-1
-2
-3
-4
0.1
APPLIED PRESSURE - KSF
1.0
SAND, VERY CLAYEY (SC)
TH-4 AT 4 FEET
100
10
DRY UNIT WEIGHT=
MOISTURE CONTENT=
98
9.2
PCF
%
3
EXPANSION UNDER CONSTANT
PRESSURE DUE TO WETTING
2
COMPRESSION % EXPANSION
1
0
-1
-2
-3
-4
0.1
APPLIED PRESSURE - KSF
1.0
SANDSTONE, CLAYEY
TH-4 AT 19 FEET
UNIVERSITY OF COLORADO AT COLORADO SPRINGS
STANTON STREET PARKING GARAGE
CTL|T PROJECT NO. CS17987-115
S:\CS17500-17999\CS17987.000\115\2. REPORTS\CS17987-115_SWELL.XLS
10
DRY UNIT WEIGHT=
MOISTURE CONTENT=
100
110
18.1
PCF
%
Swell Consolidation
Test Results
FIG. A-3
TABLE A-1
SUMMARY OF LABORATORY TESTING
CTL|T PROJECT NO. CS17987-115
BORING
TH-1
TH-1
TH-1
TH-1
TH-2
TH-2
TH-2
TH-3
TH-3
TH-3
TH-3
TH-4
TH-4
TH-4
TH-5
TH-5
TH-5
TH-5
DEPTH
(FEET)
4
9
14
24
4
9
24
4
9
14
24
4
9
19
4
9
14
29
MOISTURE
DRY
CONTENT DENSITY
(%)
(PCF)
3.2
103
2.9
110
10.7
104
18.7
102
22.2
93
5.1
103
18.7
112
6.0
103
16.7
101
24.4
101
16.3
112
9.2
98
16.6
81
18.1
110
3.9
112
16.4
98
15.1
114
20.2
104
ATTERBERG LIMITS
LIQUID
PLASTICITY
LIMIT
INDEX
(%)
(%)
* SWELL MEASURED WITH ESTIMATED IN-SITU OVERBURDEN PRESSURE.
NEGATIVE VALUE INDICATES COMPRESSION.
SWELL TEST RESULTS*
APPLIED
SWELL
SWELL PRESSURE PRESSURE
(%)
(PSF)
(PSF)
1.8
3000
1.3
0.2
0.2
1800
3000
500
0.1
2400
11000
PASSING WATER
NO. 200 SOLUBLE
SIEVE SULFATES
(%)
(%)
DESCRIPTION
14
SAND, SILTY (SM)
SAND, SILTY (SM)
26
SAND, SILTY (SM)
38
SAND, VERY CLAYEY (SC)
SAND, CLAYEY (SC)
16
SAND, SILTY (SM)
CLAYSTONE, SANDY
23
FILL, SAND, CLAYEY
<0.1
SAND, SILTY (SM)
CLAYSTONE, WEATHERED
CLAYSTONE, VERY SANDY
SAND, VERY CLAYEY (SC)
59
CLAY, VERY SANDY (CL)
SANDSTONE, CLAYEY
19
SAND, SILTY (SM)
SAND, CLAYEY (SC)
77
CLAYSTONE, SANDY
54
CLAYSTONE, VERY SANDY
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