HomeMy WebLinkAboutRIDGEWOOD HILLS FIFTH FILING - FDP200024 - SUBMITTAL DOCUMENTS - ROUND 1 - GEOTECHNICAL (SOILS) REPORT400 North Link Lane | Fort Collins, Colorado 80524
Telephone: 970-206-9455 Fax: 970-206-9441
GEOLOGIC AND PRELIMINARY
GEOTECHNICAL INVESTIGATION
TRIANGLE DRIVE AND COLLEGE AVENUE
PROPOSED RESIDENTIAL DEVELOPMENT
FORT COLLINS, COLORADO
Prepared For:
GOODWIN KNIGHT
8605 Explorer Drive, Suite 250
Colorado Springs, Colorado 80920
Attention: Mark Johnson
Project No. FC08964-115
August 28, 2019
i
TABLE OF CONTENTS
SCOPE ....................................................................................................................... 1
SUMMARY OF CONCLUSIONS ............................................................................... 1
SITE DESCRIPTION ................................................................................................. 2
PROPOSED DEVELOPMENT .................................................................................. 2
SITE GEOLOGY ........................................................................................................ 3
GEOLOGIC HAZARDS .............................................................................................. 3
Shallow Groundwater ............................................................................................. 3
Expansive Soils and Bedrock................................................................................. 4
Seismicity................................................................................................................ 4
Radioactivity ........................................................................................................... 5
FIELD AND LABORATORY INVESTIGATIONS ....................................................... 6
SUBSURFACE CONDITIONS ................................................................................... 6
DEVELOPMENT RECOMMENDATIONS ................................................................. 7
Site Grading ............................................................................................................ 7
Utility Construction .................................................................................................. 8
Underdrain System ................................................................................................. 9
PRELIMINARY PAVEMENT RECOMMENDATIONS ............................................. 11
Subgrade Preparation .......................................................................................... 11
Preliminary Pavement Thickness Design ............................................................ 11
PRELIMINARY RECOMMENDATIONS FOR STRUCTURES ............................... 12
Foundations .......................................................................................................... 12
Slabs-on-Grade and Basement Floor Construction ............................................. 12
Below-Grade Construction ................................................................................... 13
Surface Drainage ................................................................................................. 13
General Design Considerations ........................................................................... 14
WATER-SOLUBLE SULFATES .............................................................................. 15
RECOMMENDED FUTURE INVESTIGATIONS ..................................................... 15
LIMITATIONS ........................................................................................................... 16
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TABLE OF CONTENTS cont’d
FIGURE 1 – LOCATIONS OF EXPLORATORY BORINGS
FIGURE 2 – ESTIMATED BEDROCK ELEVATION
FIGURE 3 – ESTIMATED DEPTH TO BEDROCK
FIGURE 4 – ESTIMATED GROUNDWATER ELEVATION
FIGURE 5 – ESTIMATED DEPTH TO GROUNDWATER
FIGURES 6 THROUGH 8 – SEWER UNDERDRAIN DETAILS
APPENDIX A – SUMMARY LOGS OF EXPLORATORY BORINGS
APPENDIX B – LABORATORY TEST RESULTS
APPENDIX C – GUIDELINE SITE GRADING SPECIFICATIONS
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SCOPE
This report presents the results of our Geologic and Preliminary Geotechnical
Investigation. The purpose of our investigation was to identify geologic hazards that
may exist at the site and to evaluate the subsurface conditions to assist in planning
and budgeting for the proposed development. The report includes descriptions of
site geology, our analysis of the impact of geologic conditions on site development,
a description of subsoil, bedrock and groundwater conditions found in our
exploratory borings, and discussions of site development as influenced by
geotechnical considerations. The scope was described in our Service Agreement
(CTL Project No. FC-19-0237) dated June 18, 2019.
This report was prepared based upon our understanding of the development
plans. The recommendations are considered preliminary and can be used as
guidelines for further planning of development and design of grading. We should
review final development and grading plans to determine if additional investigation is
merited, or if we need to revise our recommendations. Additional investigations will
be required to design building foundations and pavements. A summary of our
findings and recommendations is presented below. More detailed discussions of
the data, analysis and recommendations are presented in the report.
SUMMARY OF CONCLUSIONS
1. The site contains geologic hazards that should be mitigated during
planning and development. No geologic or geotechnical conditions
were identified which would preclude development of this site.
Shallow groundwater, expansive soils and bedrock, and regional
issues of seismicity and radioactivity are the primary geologic
concerns pertaining to the development of the site.
2. The subsurface conditions encountered in our borings were variable
across the site. In general, the soils and bedrock encountered in our
borings consisted of 3 to 16½ feet of sandy clay over weathered and
competent bedrock to the depths explored. Bedrock consisted of
sandy claystone and in one boring, clayey sandstone.
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3. Groundwater was encountered at depths ranging from ½-foot to 23½
feet below the existing ground surface. Groundwater levels will affect
planned development over portions of the site. We recommend a
minimum of 3 feet (and preferably 5 feet) of separation between
foundations and floor systems to groundwater.
4. Generally, the overburden soils are lower swelling and the bedrock is
higher swelling. Where bedrock is shallow, we anticipate drilled pier
foundations and structural basement floors will be appropriate for
most structures. Footings and slab-on-grade basement floors can
likely be used where bedrock is deeper. Generally, bedrock is deeper
on the northwest and southwest portion of the site.
5. Pavement subgrade mitigation for swell is likely over the majority of
the site. Mitigation may consist of moisture and/or chemical treatment
of the subgrade soils. A minimum of 12 inches of chemical treatment
(fly ash or lime) should be expected. Anticipated pavement thickness
recommendations are provided in this report.
SITE DESCRIPTION
The site is located west of College Avenue and south of Triangle Drive in Fort
Collins, Colorado. Topography at the site includes rolling hills and a canal that flows
north to south through the site. The overall site slopes to the southeast. The
majority of the site is vegetated with grasses and weeds. In the area of borings TH-
11 and TH-12, wetlands were observed. At the time of our exploration, the site was
undeveloped.
PROPOSED DEVELOPMENT
We understand the parcel is planned for development of single and multi-
family residences. We assume the residences will be 1 to 2-story, wood frame
structures, with basements or crawl spaces.
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SITE GEOLOGY
The geology of the site was investigated through review of mapping by Roger
B. Colton (Geologic Map of the Boulder-Fort Collins-Greeley, 1978). According to
the referenced mapping, the site is located within an area of eolian deposition.
Eolian deposits are wind-blown and typically contain varying fractions of clay, silt
and fine sand. Nearby units include the upper Pierre Shale, which consists of sandy
claystone. We judge the bedrock encountered during our investigation is likely part
of the upper Pierre Shale unit.
GEOLOGIC HAZARDS
Our investigation identified several geologic hazards that must be considered
during the planning and development phases of this project. None of the geologic
hazards identified will preclude development of the property. Development plans
are preliminary.
Planning should consider the geologic hazards discussed below. The
hazards require mitigation which could include avoidance, non-conflicting use or
engineered design and construction during site development. Geologic hazards at
the site that need to be addressed include shallow groundwater, expansive soils
and bedrock, and regional issues of seismicity and radioactivity. The following
sections discuss each of these geologic hazards and associated development
concerns. Mitigation concepts are discussed below and in the DEVELOPMENT
RECOMMENDATIONS section of the report.
Shallow Groundwater
Groundwater was encountered during this investigation at depths of ½-foot to
23½ feet. Groundwater was shallowest at the south end of the site. Groundwater
may rise due to site development. Perched water conditions may develop where
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residential construction and irrigation occur in shallow bedrock areas. Estimated
depth and elevation contours of the groundwater are provided in Figures 4 and 5.
The depth to groundwater should be evaluated during Geotechnical
Investigations at the site. In general, grading should be designed to raise the
elevations in areas of shallow groundwater. Construction of underdrain systems with
the sanitary sewer trenches is a commonly employed method to mitigate the
accumulation of shallow groundwater after construction. A minimum separation of 5
feet is desirable between the groundwater elevations and the lowest elevation of
any below-grade structure. We recommend additional groundwater monitoring to
help determine seasonal fluctuations. Monthly readings of a year’s time frame
should be considered.
Expansive Soils and Bedrock
The soils and bedrock at this site include relatively low swelling overburden
soils and higher swelling bedrock. Areas of shallow bedrock are likely rated as high
to very high expansive potential and will require mitigation through currently utilized
foundation and floor slab techniques. We estimate approximately 75 percent of the
site will require mitigation. The northwest and southwest portions of the site where
bedrock is deeper, the risk of expansive soils is likely low to moderate. Individual
soils and foundation investigations conducted for specific sites should address
procedures for mitigating problems associated with expansive soils and bedrock.
Seismicity
This area, like most of central Colorado, is subject to a low degree of seismic
risk. No indications of recent movements of any of the faults in the Larimer County
area have been reported in the available geologic literature. As in most areas of
recognized low seismicity, the record of the past earthquake activity in Colorado is
somewhat incomplete.
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Based on the subsurface conditions encountered in our borings and our
understanding of the geology, the site classifies as a Seismic Site Class C or D
(2015 International Building Code). Only minor damage to relatively new, properly
designed and built buildings would be expected. Wind loads, not seismic
considerations, typically govern dynamic structural design in this area.
Radioactivity
It is normal in the Front Range of Colorado and nearby eastern plains to
measure radon gas in poorly ventilated spaces in contact with soil or bedrock.
Radon 222 gas is considered a health hazard and is one of several radioactive
products in the chain of the natural decay of uranium into stable lead. Radioactive
nuclides are common in the soils and sedimentary rocks underlying the subject site.
Because these sources exist on most sites, there is potential for radon gas
accumulation in poorly ventilated spaces. The amount of soil gas that can
accumulate is a function of many factors, including the radio-nuclide activity of the
soil and bedrock, construction methods and materials, pathways for soil gas and
existence of poorly-ventilated accumulation areas. It is difficult to predict the
concentration of radon gas in finished construction.
During our investigation, we did not detect any radiation levels above normal
background levels for the area. We recommend testing to evaluate radon levels
after construction is completed. If required, typical mitigation methods for residential
construction may consist of sealing soil gas entry areas and periodic ventilation of
below-grade spaces and perimeter drain systems. It is relatively economical to
provide for ventilation of perimeter drain systems or underslab gravel layers at the
time of construction, compared to retrofitting a structure after construction. Radon
rarely accumulates to significant levels in above-grade, heated and ventilated
spaces.
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FIELD AND LABORATORY INVESTIGATIONS
Subsurface conditions were further investigated by drilling twelve exploratory
borings at the approximate locations shown on Figure 1. The borings were drilled
using a truck-mounted drill rig and with 4-inch diameter, continuous-flight auger.
Our field representative observed drilling logged the soils and bedrock found in the
borings and obtained samples. Summary logs of the materials encountered in the
borings and field penetration resistance values are presented in Appendix A.
Samples of soil and bedrock were obtained during drilling by driving a
modified California-type sampler (2.5-inch O.D.) into the subsoils and bedrock using
a 140-pound hammer falling 30 inches. Samples recovered from the test holes
were returned to our laboratory and visually classified by the geotechnical engineer.
Laboratory testing included determination of moisture content and dry density,
swell-consolidation characteristics, Atterberg limits, particle-size analysis and water
soluble sulfate content. Laboratory test results are presented in Appendix B.
SUBSURFACE CONDITIONS
Subsurface conditions encountered in the borings included approximately 3
to 16½ feet of sandy clay over weathered and competent bedrock to the depths
explored. Swell potential ranged from low to moderate in the overburden sandy clay
and low to very high the bedrock. A summary of swell results is presented in Table
A. Groundwater was encountered at depths ranging from ½-foot to 23½ feet below
the existing ground surface. Groundwater levels will affect planned development at
this site in some areas. Grading should generally be designed to raise grade in
areas of shallow groundwater. A more detailed description of the subsurface
conditions is presented in our boring logs and laboratory testing. Measured depth to
and elevation of groundwater and bedrock maps are presented on Figures 2
through 5 of this report.
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TABLE A
SUMMARY OF SWELL BEHAVIOR BY SOIL TYPE
Soil Type
Compression
Range of Measured Swell (%)*
0 to <2 2 to <4 4 to <6 >6
Number of Samples and Percent
Sandy Clay 4 4 1 0 0
44% 44% 12% 0% 0%
Weathered Bedrock 0 0 1 1 3
0% 0% 20% 20% 60%
Bedrock 1 7 7 4 0
5% 37% 37% 21% 0%
Overall Sample Number 5 11 9 5 3
Overall Sample Percent 15% 33% 27% 15% 9%
DEVELOPMENT RECOMMENDATIONS
Site Grading
At the time of this investigation, site grading plans were not available for
review in conjunction with this subsurface exploration program. It is important that
deep fills (if planned) be constructed as far in advance of surface construction as
possible. It is our experience that fill compacted in accordance with the compaction
recommendations in this report may settle about 1 percent of its height under its
own weight. Most of this settlement usually occurs during and soon after
construction. Some additional settlement is possible after development and
landscape irrigation increases soil moisture. We recommend delaying the
construction of buildings underlain by deep fills as long as possible to allow for this
settlement to occur. Delaying construction of structures up to one year where
located on deep fills is recommended.
The existing on-site soils are suitable for re-use as fill material provided
debris or deleterious organic materials are removed. Prior to fill placement, all trash
and debris should be removed from fill areas and properly disposed. Import fill
should generally have similar or better engineering properties as the onsite
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materials and should be approved by CTL. The ground surface in areas to be filled
should be stripped of vegetation, topsoil and other deleterious materials, scarified to
a depth of at least 8 inches, moisture conditioned and compacted as recommended
below. The depth of any topsoil is not anticipated to be more than 2 to 3 inches in
most areas.
Site grading fill should be placed in thin, loose lifts, moisture conditioned and
compacted. In areas of deep fill, we recommend higher compaction criteria to help
reduce settlement of the fill. Compaction and moisture requirements are presented
in Appendix C. The placement and compaction of fill should be observed and
density tested during construction. Guideline site grading specifications are
presented in Appendix C.
Utility Construction
We believe excavations for utility installation in the overburden soils can be
performed with conventional heavy-duty trenchers or large backhoes. Depending
on depth and location, groundwater may be encountered in excavations. If
groundwater is encountered during construction, dewatering may be accomplished
by sloping excavations to occasional sumps where water can be removed by
pumping.
Utility trenches should be sloped or shored to meet local, State and federal
safety regulations. Based on our investigation, we believe the sandy clay soil
classifies as Type B and the bedrock classifies as Type A soil based on OSHA
standards. Excavation slopes specified by OSHA are dependent upon soil types
and groundwater conditions encountered. Seepage and groundwater conditions in
trenches may downgrade the soil type. Contractors should identify the soils
encountered in the excavation and refer to OSHA standards to determine
appropriate slopes. Excavations deeper than 20 feet should be designed by a
professional engineer.
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The width of the top of an excavation may be limited in some areas. Bracing
or “trench box” construction may be necessary. Bracing systems include sheet
piling, braced sheeting and others. Lateral loads on bracing depend on the depth of
excavation, slope of excavation above the bracing, surface loads, hydrostatic
pressures, and allowable movement. For trench boxes and bracing allowed to
move enough to mobilize the strength of the soils, with associated cracking of the
ground surface, the “active” earth pressure conditions are appropriate for design. If
movement is not tolerable, the “at rest” earth pressures are appropriate. We
suggest an equivalent fluid density of 40 pcf for the “active” earth pressure condition
and 55 pcf for the “at rest” earth pressure condition, assuming level backfill. These
pressures do not include allowances for surcharge loading or for hydrostatic
conditions. We are available to assist further with bracing design if desired.
Water and sewer lines are usually constructed beneath paved roads.
Compaction of trench backfill can have significant effect on the life and serviceability
of pavements. We believe trench backfill should be placed in thin, loose lifts, and
moisture conditioned to between optimum and 3 percent above optimum content for
clay soils and within 2 percent of optimum moisture content for sand. Trench
backfill should be compacted to at least 95 percent of maximum dry density (ASTM
D 698). The placement and compaction of fill and backfill should be observed and
tested by our firm during construction. If deep excavations are necessary for
planned utilities, the compaction requirements provided in Table C in Appendix C
should be considered.
Underdrain System
The use of underdrain systems below sewer mains and services is a
common method to control groundwater in response to development. An
underdrain system incorporated into sanitary sewer and sewer collection systems
may be considered. Underdrains should also be installed below sewer service lines
to each residence planned in this area with connection to residence foundation
drains.
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The underdrain should consist of free-draining gravel surrounding a rigid PVC
pipe. The pipe should be sized for anticipated flow. Guidelines for underdrain
sizing are shown in Table B. The line should consist of smooth, perforated or
slotted rigid PVC pipe laid at a grade of at least 0.5 percent. A gravel cross-section
of at least 2 square feet should be placed around the pipe. Sewer underdrain
details are shown on Figures 6 through 8. A positive cutoff collar (concrete) should
be constructed around the sewer pipe and underdrain pipe immediately downstream
of the point the underdrain pipe leaves the sewer trench. Solid pipe should be used
down gradient of this collar to the daylight point. Clean-outs should be provided
along the system. The entity responsible for maintenance should be identified and
guidelines developed for maintenance. The underdrain should be designed to
discharge to a gravity outfall provided with a permanent concrete headwall and trash
rack, or to a storm sewer with a check valve to control water backing up into the
underdrain system. The underdrain system should be designed by a professional
engineer that is licensed in the State of Colorado.
TABLE B
UNDERDRAIN SIZING
Slope = 0.005 (0.5 percent)
Pipe Size (inches) 4 6 8
Maximum Number of Residences 50 100 200
Slope = 0.01 (1.0 percent)
Pipe Size (inches) 4 6 8
Maximum Number of Residences 75 150 300
Slope = 0.02 (2.0 percent)
Pipe Size (inches) 4 6
Maximum Number of Residences 100 300
Note: Minimum slopes of the underdrains will govern pipe sizes and
maximum number of residences serviced.
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PRELIMINARY PAVEMENT RECOMMENDATIONS
Subgrade Preparation
Based on the borings, the near surface soils on this site will consist of sandy
clay. These soils will range from moderately to highly plastic and will provide
relatively poor subgrade support below the pavements. Lime or fly ash stabilization
of these soils will improve their subgrade support characteristics, in addition to
enhancing the workability of the clays and reducing water infiltration into the
underlying subgrade and the potential movements under the pavements. The City
of Fort Collins typically requires a minimum 12 inches of fly ash for soils similar to
those encountered at this site.
Preliminary Pavement Thickness Design
Preliminary guidelines for pavement systems on this site are provided. Final
pavement sections should be determined based a design level geotechnical
investigation and anticipated frequency of load applications on the pavement during
the desired design life. Flexible hot mix asphalt (HMA) over aggregate base course
(ABC) or rigid Portland cement concrete (PCC) pavements can be used at this site
for automobile and light truck traffic use. Rigid pavements are recommended in any
areas subject to heavy truck traffic. We anticipate pavement sections for local
residential streets will consist of approximately 4 to 5 inches of HMA over 6 to 8
inches of ABC. Collectors and other higher volume pavement will likely require
thicker HMA sections, estimated on the order 6 to 7 inches.
Portland cement concrete (PCC) pavement is recommended in areas subject
to any heavy truck traffic such as garbage pickup and/or dumpster trucks and any
heavy delivery trucks. A minimum 6-inch thick section is anticipated in main drives
and any areas subject to some moderately heavy truck traffic. Any areas subject to
frequent heavy trucks should be designed based on frequency and wheel loads.
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PCC pavements in this area are typically reinforced due to the underlying active
clays. Properly designed control joints and other joints systems are required to
control cracking and allow pavement movement.
PRELIMINARY RECOMMENDATIONS FOR STRUCTURES
The property is currently planned for residential construction. Our field and
laboratory data indicate the soil and bedrock conditions vary across the site. The
following discussions are preliminary and are not intended for design or
construction. After grading is completed, a detailed soils and foundation
investigation should be performed.
Foundations
Our geologic and preliminary geotechnical investigation indicates conditions
vary across the site. Areas of shallow bedrock will likely require drilled piers. The
northwest and southwest portions of the site where bedrock is deeper, shallow
foundations are likely. We estimate approximately 75 percent of the site will require
a deep foundation system. A design level geotechnical investigation may identify
potential hazards for specified areas not indicated by our borings which may
suggest the need for a deeper foundation system in more areas of the site.
Slabs-on-Grade and Basement Floor Construction
The use of slab-on-grade floors for unfinished basements should be limited
to areas where the slab risk performance is low to moderate. Generally, we believe
the northwestern and southwestern portions of the site will likely be lower risk due to
the depth of bedrock. Structurally supported floor systems should be planned in all
non-basement finished living areas and in basements where slab risk is judged high
or very high (generally where bedrock is shallow). We believe approximately 75
percent of the lots will be rated high to very high risk for poor slab performance.
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Slab performance risk should be more thoroughly defined during the design level
soils and foundation investigation.
Below-Grade Construction
Groundwater was encountered during this investigation. Groundwater levels
may limit below-grade construction in areas of the site. With long-term development
and associated landscaping, a “perched” water table may develop on the bedrock
surface or on relatively impermeable soils and bedrock layers. To reduce the risk of
hydrostatic pressure developing on foundation walls, foundation drains will be
necessary around all below-grade areas. We suggest foundation drains be tied to
the sewer underdrain system. They may also discharge to sumps where water can
be removed by pumping. In our opinion, underdrain systems offer more
comprehensive control of groundwater and better mitigate impacts of groundwater
and swelling soils on foundations, slabs and pavements. Foundation walls and
grade beams should be designed to withstand lateral earth pressures. The design
pressure should be established during design-level soils investigations.
Surface Drainage
The performance of foundations will be influenced by surface drainage. The
ground surface around proposed residences should be shaped to provide runoff of
surface water away from the structure and off of pavements. We generally
recommend slopes of at least 12 inches in the first 10 feet where practical in the
landscaping areas surrounding residences. There are practical limitations on
achieving these slopes. Irrigation should be minimized to control wetting. Roof
downspouts should discharge beyond the limits of backfill. Water should not be
allowed to pond on or adjacent to pavements. Proper control of surface runoff is
also important to limit 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 re-vegetated to reduce erosion.
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Water can follow poorly compacted fill behind curb and gutter and in utility
trenches. This water can soften fill and undermine the performance of the
roadways, flatwork and foundations. We recommend compactive effort be used in
placement of all fill.
General Design Considerations
Exterior sidewalks and pavements supported above the on-site clays are
subject to post construction movement. Flat grades should be avoided to prevent
possible ponding, particularly next to structures and pavements due to soil
movement. Positive grades away from the buildings should be used for sidewalks
and flatwork around the perimeter of the buildings in order to reduce the possibility
of lifting of this flatwork, resulting in ponding next to the structures. Where
movement of the flatwork is objectionable, procedures recommended for on-grade
floor slabs should be considered.
Joints next to buildings should be thoroughly sealed to prevent the infiltration
of surface water. Where concrete pavement is used, joints should also be sealed to
reduce the infiltration of water. Since some post construction movement of
pavement and flatwork may occur, joints around the buildings should be periodically
observed and resealed where necessary.
Roof drains should be discharged well away from the structures, preferably
by closed pipe systems. Where roof drains are allowed to discharge on concrete
flatwork or pavement areas next to the structures, care should be taken to insure
the area is as water tight as practical to eliminate the infiltration of this water next to
the buildings.
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WATER-SOLUBLE SULFATES
Concrete that comes into contact with soils can be subject to sulfate attack.
We measured water-soluble sulfate concentrations in four samples from this site.
The measured concentrations ranged from below measurable limits (less than 0.01
percent) to 0.57 percent, with one sample having a sulfate concentration greater
than 0.1 percent. Based on the range of results, we judge the site has Class 1
exposure to sulfates. Additional sulfate testing should be performed during a
design-level investigation. Water-soluble sulfate concentrations between 0.1 and
0.2 percent indicate Class 1 exposure to sulfate attack, according to the American
Concrete Institute (ACI). ACI indicates adequate sulfate resistance can be achieved
by using Type II cement with a water-to-cementitious material ratio of 0.50 or less.
ACI also indicates concrete in Class 1 exposure environments should have a
minimum compressive strength of 4,000 psi. 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 should be air entrained.
RECOMMENDED FUTURE INVESTIGATIONS
Based on the results of this investigation and the proposed development, we
recommend the following investigations be performed:
1. Additional groundwater monitoring;
2. Review of final site grading plans by our firm;
3. Design and sizing of the underdrain systems;
4. Construction testing and observation for site development;
5. Subgrade investigation and pavement design after site grading is
complete;
TH-1
TH-2
TH-3
TH-7
TH-4 TH-5
TH-6
TH-8
TH-9
TH-10
TH-12
TH-11
South College Avenue
Triangle Drive
HWY 287 / COLLEGE AVE.
HWY 392 / CARPENTER RD.
TRILBY RD.
SHIELDS ST.
SITE
TRIANGLE DR.
LEGEND:
INDICATES APPROXIMATE
LOCATION OF EXPLORATORY
BORING
TH-1
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FIGURE 1
Locations of
Exploratory
Borings
VI CINITY MAP
(FORT COLLINS, COLORADO)
NOT TO SCALE
125' 250'
APPROXIMATE
SCALE: 1" = 250'
0'
South College Avenue
Triangle Drive
5040
5050
5060
5070
5042
5044
5046
5048
5052
5054
5056
5058
5062
5064
5066
5068
5050
5060
5046
5048
5052
5054
5056
5058
5062
5064
5066
5068
5030
5040
5050
5060
5032
5034
5036
5038
5042
5044
5046
5048
5052
5054
5056
5058
5062
5064
5038
5036
5034
5032
5030
5028
5028
5026
5024
TH-1
TH-2
TH-7
South College Avenue
Triangle Drive
(10)
(10)
(6)
(6)
(8)
(8)
(12)
(12)
(14)
(14)
(10)
(4)
(6)
(8)
(12)
TH-1
TH-2
TH-3
TH-7
TH-4 TH-5
TH-6
TH-8
TH-9
TH-10
TH-11
TH-12
(4.0)
(12.5)
(3.0)
(12.0) (10.0)
(11.0)
(6.0)
(15.0)
(11.0)
(7.0)
(4.0)
(16.5)
HWY 287 / COLLEGE AVE.
HWY 392 / CARPENTER RD.
TRILBY RD.
SHIELDS ST.
SITE
TRIANGLE DR.
LEGEND:
INDICATES APPROXIMATE
LOCATION OF EXPLORATORY
BORING
INDICATES ESTIMATED BEDROCK
DEPTH IN FEET
(23)
TH-1
GOODWIN KNIGHT
TRIANGLE DRIVE AND COLLEGE AVENUE DEVELOPMENT
CTL I T PROJECT NO. FC08964-115
FIGURE 3
Estimated Depth
To Bedrock
VICINITY MAP
South College Avenue
Triangle Drive
5020
5030
5040
5018
5022
5024
5026
5028
5032
5034
5036
5038
5042
5044
5030
5040
5050
5060
5024
5026
5028
5032
5034
5036
5038
5042
5044
5046
5048
5052
5054
5056
5058
5062
5040
5050
5042
5044
5046
5048
5052
5054
5056
5058
5038
5060
5036
5062
5064
5022
5020
5018
5018
TH-1
TH-2
TH-3
TH-7
TH-4 TH-5
South College Avenue
Triangle Drive
(10)
(2)
(4)
(6)
(8)
(12)
(14)
(10)
(10)
(20)
(12)
(12)
(14)
(16)
(18)
(22)
(20)
(12)
(14)
(16)
(18)
TH-1
TH-2
TH-3
TH-7
TH-4 TH-5
TH-6
TH-8
TH-9
TH-10
TH-12
TH-11
(16.0)
(15.0)
(20.0)
(13.0) (9.0)
(10.0)
(23.5)
(>25)
(>25)
(14.5)
(8.0)
(0.5)
HWY 287 / COLLEGE AVE.
HWY 392 / CARPENTER RD.
TRILBY RD.
SHIELDS ST.
SITE
TRIANGLE DR.
LEGEND:
INDICATES APPROXIMATE
LOCATION OF EXPLORATORY
BORING
INDICATES ESTIMATED DEPTH TO
GROUNDWATER IN FEET
(10.0)
TH-1
GOODWIN KNIGHT
FIGURE 6
Detail
Underdrain
Sewer
CTL|T PROJECT NO. FC08964-115
GOODWIN KNIGHT
TRIANGLE DRIVE AND COLLEGE AVENUE DEVELOPMENT
FIGURE 7
Cutoff Wall
Underdrain
CTL|T PROJECT NO. FC08964-115
GOODWIN KNIGHT
TRIANGLE DRIVE AND COLLEGE AVENUE DEVELOPMENT
Conceptual
Underdrain
Service Profile
CTL|T PROJECT NO. FC08964-115 FIGURE 8
TRIANGLE DRIVE AND COLLEGE AVENUE DEVELOPMENT
GOODWIN KNIGHT
APPENDIX A
LOGS OF EXPLORATORY BORINGS
0
5
10
15
20
25
30
35
40
0
5
10
15
20
25
30
35
29/12
47/12
50/9
50/6
50/4
WC=18.3
DD=112
SW=7.3
WC=16.7
DD=116
SW=4.5
-200=98
WC=18.3
DD=112
SW=7.3
WC=16.7
DD=116
SW=4.5
-200=98
TH-1
El. 5030.7
17/12
18/12
37/12
50/10
50/7
WC=12.6
DD=114
LL=42 PI=29
-200=76
WC=9.7
DD=98
SW=-1.7
SS=0.030
WC=14.5
DD=121
SW=2.8
-200=98
WC=12.6
DD=114
LL=42 PI=29
-200=76
WC=9.7
0
5
10
15
20
25
30
35
40
0
5
10
15
20
25
30
35
40
15/12
16/12
22/12
50/9
50/10
WC=18.9
DD=106
SW=0.0
-200=75
WC=16.7
DD=117
SW=3.2
WC=18.9
DD=106
SW=0.0
-200=75
WC=16.7
DD=117
SW=3.2
TH-5
El. 5059.5
17/12
15/12
31/12
50/8
50/7
WC=9.6
DD=107
SW=1.0
SS=0.030
WC=19.8
DD=109
SW=2.4
WC=15.2
DD=118
SW=1.8
WC=9.6
DD=107
SW=1.0
SS=0.030
WC=19.8
DD=109
0
5
10
15
20
25
30
35
40
0
5
10
15
20
25
30
35
40
19/12
16/12
38/12
50/9
50/7
WC=9.9
DD=95
SW=2.1
WC=15.1
DD=116
SW=5.8
-200=99
WC=9.9
DD=95
SW=2.1
WC=15.1
DD=116
SW=5.8
-200=99
TH-9
El. 5073.7
41/12
50/5
50/5
50/11
50/9
WC=7.6
DD=135
SW=2.3
SS=<0.01
WC=12.0
DD=125
SW=0.3
WC=7.6
DD=135
SW=2.3
SS=<0.01
WC=12.0
DD=125
SW=0.3
TH-10
El. 5073.4
APPENDIX B
LABORATORY TEST RESULTS
TABLE B-I: SUMMARY OF LABORATORY TEST RESULTS
Sample of WEATHERED CLAYSTONE DRY UNIT WEIGHT= 112 PCF
From TH - 1 AT 4 FEET MOISTURE CONTENT= 18.3 %
GOODWIN KNIGHT
TRIANGLE DRIVE AND COLLEGE AVENUE DEVELOPMENT
CTL | T PROJECT NO. FC08964-115
APPLIED PRESSURE - KSF
COMPRESSION % EXPANSION
Swell Consolidation
Test Results
FIGURE B-1
-6
-5
-4
-3
-2
-1
0
1
2
3
4
5
6
7
8
9
EXPANSION UNDER CONSTANT
PRESSURE DUE TO WETTING
0.1 1.0 10 100
Sample of CLAYSTONE DRY UNIT WEIGHT= 116 PCF
From TH - 1 AT 14 FEET MOISTURE CONTENT= 16.7 %
GOODWIN KNIGHT
TRIANGLE DRIVE AND COLLEGE AVENUE DEVELOPMENT
CTL | T PROJECT NO. FC08964-115
APPLIED PRESSURE - KSF
COMPRESSION % EXPANSION
Swell Consolidation
Test Results
FIGURE B-2
-8
-7
-6
-5
-4
-3
-2
-1
0
1
2
3
4
5
6
7
EXPANSION UNDER CONSTANT
PRESSURE DUE TO WETTING
0.1 1.0 10 100
Sample of CLAY, SANDY (CL) DRY UNIT WEIGHT= 98 PCF
From TH - 2 AT 9 FEET MOISTURE CONTENT= 9.7 %
Sample of CLAYSTONE DRY UNIT WEIGHT= 121 PCF
From TH - 2 AT 19 FEET MOISTURE CONTENT= 14.5 %
GOODWIN KNIGHT
TRIANGLE DRIVE AND COLLEGE AVENUE DEVELOPMENT
CTL | T PROJECT NO. FC08964-115
APPLIED PRESSURE - KSF
APPLIED PRESSURE - KSF
COMPRESSION % EXPANSION
Swell Consolidation
Test Results FIGURE B-3
COMPRESSION % EXPANSION
-4
-3
-2
-1
0
1
2
3
ADDITIONAL COMPRESSION UNDER
CONSTANT PRESSURE DUE TO
WETTING
-4
-3
-2
-1
0
1
2
3
EXPANSION UNDER CONSTANT
PRESSURE DUE TO WETTING
0.1 1.0 10 100
0.1
1.0
10 100
Sample of DRY UNIT WEIGHT= 120 PCF
From TH - 3 AT 4 FEET MOISTURE CONTENT= 12.8 %
GOODWIN KNIGHT
TRIANGLE DRIVE AND COLLEGE AVENUE DEVELOPMENT
CTL | T PROJECT NO. FC08964-115
APPLIED PRESSURE - KSF
COMPRESSION % EXPANSION
Swell Consolidation
Test Results
FIGURE B-4
-5
-4
-3
-2
-1
0
1
2
3
4
5
6
7
8
9
10
EXPANSIONUC NDER O NST ANT
P RE SS U RE D UE TO W ETTIN G
0.1 1.0 10 100
WEATHERED CLAYSTONE
Sample of CLAYSTONE DRY UNIT WEIGHT= 114 PCF
From TH - 3 AT 9 FEET MOISTURE CONTENT= 15.1 %
GOODWIN KNIGHT
TRIANGLE DRIVE AND COLLEGE AVENUE DEVELOPMENT
CTL | T PROJECT NO. FC08964-115
APPLIED PRESSURE - KSF
COMPRESSION % EXPANSION
Swell Consolidation
Test Results
FIGURE B-5
-8
-7
-6
-5
-4
-3
-2
-1
0
1
2
3
4
5
6
7
EXPANSION UNDER CONSTANT
PRESSURE DUE TO WETTING
0.1 1.0 10 100
Sample of CLAYSTONE DRY UNIT WEIGHT= 115 PCF
From TH - 3 AT 14 FEET MOISTURE CONTENT= 17.0 %
GOODWIN KNIGHT
TRIANGLE DRIVE AND COLLEGE AVENUE DEVELOPMENT
CTL | T PROJECT NO. FC08964-115
APPLIED PRESSURE - KSF
COMPRESSION % EXPANSION
Swell Consolidation
Test Results
FIGURE B-6
-8
-7
-6
-5
-4
-3
-2
-1
0
1
2
3
4
5
6
7
EXPANSION UNDER CONSTANT
PRESSURE DUE TO WETTING
0.1 1.0 10 100
Sample of CLAYSTONE DRY UNIT WEIGHT= 112 PCF
From TH - 3 AT 19 FEET MOISTURE CONTENT= 17.3 %
Sample of CLAYSTONE DRY UNIT WEIGHT= 110 PCF
From TH - 3 AT 24 FEET MOISTURE CONTENT= 19.5 %
GOODWIN KNIGHT
TRIANGLE DRIVE AND COLLEGE AVENUE DEVELOPMENT
CTL | T PROJECT NO. FC08964-115
APPLIED PRESSURE - KSF
APPLIED PRESSURE - KSF
COMPRESSION % EXPANSION
Swell Consolidation
Test Results FIGURE B-7
COMPRESSION % EXPANSION
-4
-3
-2
-1
0
1
2
3
EXPANSION UNDER CONSTANT
PRESSURE DUE TO WETTING
-4
-3
-2
-1
0
1
2
3
EXPANSION UNDER CONSTANT
PRESSURE DUE TO WETTING
0.1 1.0 10 100
0.1
1.0
10 100
Sample of CLAY, SANDY (CL) DRY UNIT WEIGHT= 98 PCF
From TH - 4 AT 4 FEET MOISTURE CONTENT= 9.9 %
Sample of SANDSTONE DRY UNIT WEIGHT= 128 PCF
From TH - 4 AT 14 FEET MOISTURE CONTENT= 11.2 %
GOODWIN KNIGHT
TRIANGLE DRIVE AND COLLEGE AVENUE DEVELOPMENT
CTL | T PROJECT NO. FC08964-115
APPLIED PRESSURE - KSF
APPLIED PRESSURE - KSF
COMPRESSION % EXPANSION
Swell Consolidation
Test Results FIGURE B-8
COMPRESSION % EXPANSION
-4
-3
-2
-1
0
1
2
3
EXPANSION UNDER CONSTANT
PRESSURE DUE TO WETTING
-4
-3
-2
-1
0
1
2
3
EXPANSION UNDER CONSTANT
PRESSURE DUE TO WETTING
0.1 1.0 10 100
0.1
1.0
10 100
Sample of CLAY, SANDY (CL) DRY UNIT WEIGHT= 106 PCF
From TH - 5 AT 9 FEET MOISTURE CONTENT= 18.9 %
Sample of CLAYSTONE DRY UNIT WEIGHT= 117 PCF
From TH - 5 AT 19 FEET MOISTURE CONTENT= 16.7 %
GOODWIN KNIGHT
TRIANGLE DRIVE AND COLLEGE AVENUE DEVELOPMENT
CTL | T PROJECT NO. FC08964-115
APPLIED PRESSURE - KSF
APPLIED PRESSURE - KSF
COMPRESSION % EXPANSION
Swell Consolidation
Test Results FIGURE B-9
COMPRESSION % EXPANSION
-4
-3
-2
-1
0
1
2
3
NO MOVEMENT DUE TO WETTING
-4
-3
-2
-1
0
1
2
3
EXPANSION UNDER CONSTANT
PRESSURE DUE TO WETTING
0.1 1.0 10 100
0.1
1.0
10 100
Sample of CLAY, SANDY (CL) DRY UNIT WEIGHT= 107 PCF
From TH - 6 AT 4 FEET MOISTURE CONTENT= 9.6 %
Sample of WEATHERED CLAYSTONE DRY UNIT WEIGHT= 109 PCF
From TH - 6 AT 14 FEET MOISTURE CONTENT= 19.8 %
GOODWIN KNIGHT
TRIANGLE DRIVE AND COLLEGE AVENUE DEVELOPMENT
CTL | T PROJECT NO. FC08964-115
APPLIED PRESSURE - KSF
APPLIED PRESSURE - KSF
COMPRESSION % EXPANSION
Swell Consolidation
Test Results FIGURE B-10
COMPRESSION % EXPANSION
-4
-3
-2
-1
0
1
2
3
EXPANSION UNDER CONSTANT
PRESSURE DUE TO WETTING
-4
-3
-2
-1
0
1
2
3
EXPANSION UNDER CONSTANT
PRESSURE DUE TO WETTING
0.1 1.0 10 100
0.1
1.0
10 100
Sample of CLAYSTONE DRY UNIT WEIGHT= 118 PCF
From TH - 6 AT 24 FEET MOISTURE CONTENT= 15.2 %
GOODWIN KNIGHT
TRIANGLE DRIVE AND COLLEGE AVENUE DEVELOPMENT
CTL | T PROJECT NO. FC08964-115
APPLIED PRESSURE - KSF
COMPRESSION % EXPANSION
Swell Consolidation
Test Results
FIGURE B-11
-8
-7
-6
-5
-4
-3
-2
-1
0
1
2
3
4
5
6
7
EXPANSION UNDER CONSTANT
PRESSURE DUE TO WETTING
0.1 1.0 10 100
Sample of WEATHERED CLAYSTONE DRY UNIT WEIGHT= 113 PCF
From TH - 7 AT 9 FEET MOISTURE CONTENT= 15.6 %
GOODWIN KNIGHT
TRIANGLE DRIVE AND COLLEGE AVENUE DEVELOPMENT
CTL | T PROJECT NO. FC08964-115
APPLIED PRESSURE - KSF
COMPRESSION % EXPANSION
Swell Consolidation
Test Results
FIGURE B-12
-8
-7
-6
-5
-4
-3
-2
-1
0
1
2
3
4
5
6
7
EXPANSION UNDER CONSTANT
PRESSURE DUE TO WETTING
0.1 1.0 10 100
Sample of CLAYSTONE DRY UNIT WEIGHT= 113 PCF
From TH - 7 AT 19 FEET MOISTURE CONTENT= 16.7 %
GOODWIN KNIGHT
TRIANGLE DRIVE AND COLLEGE AVENUE DEVELOPMENT
CTL | T PROJECT NO. FC08964-115
APPLIED PRESSURE - KSF
COMPRESSION % EXPANSION
Swell Consolidation
Test Results
FIGURE B-13
-8
-7
-6
-5
-4
-3
-2
-1
0
1
2
3
4
5
6
7
EXPANSION UNDER CONSTANT
PRESSURE DUE TO WETTING
0.1 1.0 10 100
Sample of CLAY, SANDY (CL) DRY UNIT WEIGHT= 88 PCF
From TH - 8 AT 4 FEET MOISTURE CONTENT= 7.0 %
GOODWIN KNIGHT
TRIANGLE DRIVE AND COLLEGE AVENUE DEVELOPMENT
CTL | T PROJECT NO. FC08964-115
APPLIED PRESSURE - KSF
COMPRESSION % EXPANSION
Swell Consolidation
Test Results
FIGURE B-14
-18
-17
-16
-15
-14
-13
-12
-11
-10
-9
-8
-7
-6
-5
-4
-3
-2
-1
0
ADDITIONAL COMPRESSION UNDER
CONSTANT PRESSURE DUE TO WETTING
0.1 1.0 10 100
Sample of CLAY, SANDY (CL) DRY UNIT WEIGHT= 95 PCF
From TH - 8 AT 9 FEET MOISTURE CONTENT= 9.8 %
Sample of CLAY, SANDY (CL) DRY UNIT WEIGHT= 106 PCF
From TH - 8 AT 14 FEET MOISTURE CONTENT= 7.6 %
GOODWIN KNIGHT
TRIANGLE DRIVE AND COLLEGE AVENUE DEVELOPMENT
CTL | T PROJECT NO. FC08964-115
APPLIED PRESSURE - KSF
APPLIED PRESSURE - KSF
COMPRESSION % EXPANSION
Swell Consolidation
Test Results FIGURE B-15
COMPRESSION % EXPANSION
-4
-3
-2
-1
0
1
2
3
EXPANSION UNDER CONSTANT
PRESSURE DUE TO WETTING
-4
-3
-2
-1
0
1
2
3
ADDITIONAL COMPRESSION UNDER
CONSTANT PRESSURE DUE TO
WETTING
0.1 1.0 10 100
0.1
1.0
10 100
Sample of CLAYSTONE DRY UNIT WEIGHT= 121 PCF
From TH - 8 AT 19 FEET MOISTURE CONTENT= 14.3 %
Sample of CLAYSTONE DRY UNIT WEIGHT= 122 PCF
From TH - 8 AT 24 FEET MOISTURE CONTENT= 14.1 %
GOODWIN KNIGHT
TRIANGLE DRIVE AND COLLEGE AVENUE DEVELOPMENT
CTL | T PROJECT NO. FC08964-115
APPLIED PRESSURE - KSF
APPLIED PRESSURE - KSF
COMPRESSION % EXPANSION
Swell Consolidation
Test Results FIGURE B-16
COMPRESSION % EXPANSION
-3
-2
-1
0
1
2
3
4
EXPANSION UNDER CONSTANT
PRESSURE DUE TO WETTING
-4
-3
-2
-1
0
1
2
3
EXPANSION UNDER CONSTANT
PRESSURE DUE TO WETTING
0.1 1.0 10 100
0.1
1.0
10 100
Sample of CLAY, SANDY (CL) DRY UNIT WEIGHT= 95 PCF
From TH - 9 AT 4 FEET MOISTURE CONTENT= 9.9 %
GOODWIN KNIGHT
TRIANGLE DRIVE AND COLLEGE AVENUE DEVELOPMENT
CTL | T PROJECT NO. FC08964-115
APPLIED PRESSURE - KSF
COMPRESSION % EXPANSION
Swell Consolidation
Test Results
FIGURE B-17
-8
-7
-6
-5
-4
-3
-2
-1
0
1
2
3
4
5
6
7
EXPANSION UNDER CONSTANT
PRESSURE DUE TO WETTING
0.1 1.0 10 100
Sample of CLAYSTONE DRY UNIT WEIGHT= 116 PCF
From TH - 9 AT 14 FEET MOISTURE CONTENT= 15.1 %
GOODWIN KNIGHT
TRIANGLE DRIVE AND COLLEGE AVENUE DEVELOPMENT
CTL | T PROJECT NO. FC08964-115
APPLIED PRESSURE - KSF
COMPRESSION % EXPANSION
Swell Consolidation
Test Results
FIGURE B-18
-8
-7
-6
-5
-4
-3
-2
-1
0
1
2
3
4
5
6
7
EXPANSION UNDER CONSTANT
PRESSURE DUE TO WETTING
0.1 1.0 10 100
Sample of CLAYSTONE DRY UNIT WEIGHT= 135 PCF
From TH - 10 AT 9 FEET MOISTURE CONTENT= 7.6 %
Sample of CLAYSTONE DRY UNIT WEIGHT= 125 PCF
From TH - 10 AT 19 FEET MOISTURE CONTENT= 12.0 %
GOODWIN KNIGHT
TRIANGLE DRIVE AND COLLEGE AVENUE DEVELOPMENT
CTL | T PROJECT NO. FC08964-115
APPLIED PRESSURE - KSF
APPLIED PRESSURE - KSF
COMPRESSION % EXPANSION
Swell Consolidation
Test Results FIGURE B-19
COMPRESSION % EXPANSION
-4
-3
-2
-1
0
1
2
3
EXPANSION UNDER CONSTANT
PRESSURE DUE TO WETTING
-4
-3
-2
-1
0
1
2
3
EXPANSION UNDER CONSTANT
PRESSURE DUE TO WETTING
0.1 1.0 10 100
0.1
1.0
10 100
Sample of WEATHERED CLAYSTONE DRY UNIT WEIGHT= 122 PCF
From TH - 11 AT 4 FEET MOISTURE CONTENT= 11.9 %
GOODWIN KNIGHT
TRIANGLE DRIVE AND COLLEGE AVENUE DEVELOPMENT
CTL | T PROJECT NO. FC08964-115
APPLIED PRESSURE - KSF
COMPRESSION % EXPANSION
Swell Consolidation
Test Results
FIGURE B-20
-5
-4
-3
-2
-1
0
1
2
3
4
5
6
7
8
9
10
11
12
13
EXPANSION UNDER CONSTANT
PRESSURE DUE TO WETTING
0.1 1.0 10 100
Sample of CLAYSTONE DRY UNIT WEIGHT= 118 PCF
From TH - 11 AT 9 FEET MOISTURE CONTENT= 12.9 %
Sample of CLAYSTONE DRY UNIT WEIGHT= 113 PCF
From TH - 11 AT 14 FEET MOISTURE CONTENT= 13.1 %
GOODWIN KNIGHT
TRIANGLE DRIVE AND COLLEGE AVENUE DEVELOPMENT
CTL | T PROJECT NO. FC08964-115
APPLIED PRESSURE - KSF
APPLIED PRESSURE - KSF
COMPRESSION % EXPANSION
Swell Consolidation
Test Results FIGURE B-21
COMPRESSION % EXPANSION
-3
-2
-1
0
1
2
3
4
EXPANSION UNDER CONSTANT
PRESSURE DUE TO WETTING
-4
-3
-2
-1
0
1
2
3
ADDITIONAL COMPRESSION UNDER
CONSTANT PRESSURE DUE TO
WETTING
0.1 1.0 10 100
0.1
1.0
10 100
Sample of CLAYSTONE DRY UNIT WEIGHT= 122 PCF
From TH - 11 AT 19 FEET MOISTURE CONTENT= 12.5 %
Sample of CLAYSTONE DRY UNIT WEIGHT= 124 PCF
From TH - 11 AT 24 FEET MOISTURE CONTENT= 14.2 %
GOODWIN KNIGHT
TRIANGLE DRIVE AND COLLEGE AVENUE DEVELOPMENT
CTL | T PROJECT NO. FC08964-115
APPLIED PRESSURE - KSF
APPLIED PRESSURE - KSF
COMPRESSION % EXPANSION
Swell Consolidation
Test Results FIGURE B-22
COMPRESSION % EXPANSION
-4
-3
-2
-1
0
1
2
3
EXPANSION UNDER CONSTANT
PRESSURE DUE TO WETTING
-4
-3
-2
-1
0
1
2
3
EXPANSION UNDER CONSTANT
PRESSURE DUE TO WETTING
0.1 1.0 10 100
0.1
1.0
10 100
Sample of CLAY, SANDY (CL) DRY UNIT WEIGHT= 104 PCF
From TH - 12 AT 14 FEET MOISTURE CONTENT= 23.3 %
GOODWIN KNIGHT
TRIANGLE DRIVE AND COLLEGE AVENUE DEVELOPMENT
CTL | T PROJECT NO. FC08964-115
APPLIED PRESSURE - KSF
COMPRESSION % EXPANSION
Swell Consolidation
Test Results
FIGURE B-23
-8
-7
-6
-5
-4
-3
-2
-1
0
1
2
3
4
5
6
7
ADDITIONAL COMPRESSION UNDER
CONSTANT PRESSURE DUE TO WETTING
0.1 1.0 10 100
PASSING WATER-
MOISTURE DRY LIQUID PLASTICITY APPLIED SWELL NO. 200 SOLUBLE
DEPTH CONTENT DENSITY LIMIT INDEX SWELL* PRESSURE PRESSURE SIEVE SULFATES
BORING (FEET) (%) (PCF) (%) (PSF) (PSF) (%) (%) DESCRIPTION
TH-1 4 18.3 112 7.3 500 WEATHERED CLAYSTONE
TH-1 14 16.7 116 4.5 1,800 98 CLAYSTONE
TH-2 4 12.6 114 42 29 76 CLAY, SANDY (CL)
TH-2 9 9.7 98 -1.7 1,100 0.03 CLAY, SANDY (CL)
TH-2 19 14.5 121 2.8 2,400 98 CLAYSTONE
TH-3 4 12.8 120 8.4 500 19,000 97
TH-3 9 15.1 114 5.2 1,100 17,000 CLAYSTONE
TH-3 14 17.0 115 4.7 1,800 18,000 CLAYSTONE
TH-3 19 17.3 112 1.6 2,400 8,800 CLAYSTONE
TH-3 24 19.5 110 2.4 3,000 13,000 CLAYSTONE
TH-4 4 9.9 98 1.4 500 CLAY, SANDY (CL)
TH-4 14 11.2 128 0.5 1,800 SANDSTONE
TH-5 9 18.9 106 0.0 1,100 75 CLAY, SANDY (CL)
TH-5 19 16.7 117 3.2 2,400 CLAYSTONE
TH-6 4 9.6 107 1.0 500 0.03 CLAY, SANDY (CL)
TH-6 14 19.8 109 2.4 1,800 WEATHERED CLAYSTONE
TH-6 24 15.2 118 1.8 3,000 CLAYSTONE
TH-7 4 11.8 105 44 29 86 CLAY, SANDY (CL)
TH-7 9 15.6 113 5.3 1,100 WEATHERED CLAYSTONE
TH-7 19 16.7 113 2.8 2,400 96 CLAYSTONE
TH-8 4 7.0 88 -2.6 500 67 CLAY, SANDY (CL)
TH-8 9 9.8 95 0.1 1,100 1,400 CLAY, SANDY (CL)
TH-8 14 7.6 106 -0.1 1,800 CLAY, SANDY (CL)
TH-8 19 14.3 121 3.4 2,400 CLAYSTONE
TH-8 24 14.1 122 1.3 3,000 13,000 CLAYSTONE
TH-9 4 9.9 95 2.1 500 CLAY, SANDY (CL)
TH-9 14 15.1 116 5.8 1,800 99 CLAYSTONE
TH-10 9 7.6 135 2.3 1,100 <0.01 CLAYSTONE
TH-10 19 12.0 125 0.3 2,400 CLAYSTONE
TH-11 4 11.9 122 11.5 500 18,000 0.57 WEATHERED CLAYSTONE
TH-11 9 12.9 118 3.4 1,100 8,500 98 CLAYSTONE
SWELL TEST RESULTS*
TABLE B-I
SUMMARY OF LABORATORY TESTING
ATTERBERG LIMITS
Page 1 of 2
* NEGATIVE VALUE INDICATES COMPRESSION.
GOODWIN KNIGHT
TRIANGLE DRIVE AND COLLEGE AVENUE DEVELOPMENT
CTL|T PROJECT NO. FC08964-115
WEATHERED CLAYSTONE
PASSING WATER-
MOISTURE DRY LIQUID PLASTICITY APPLIED SWELL NO. 200 SOLUBLE
DEPTH CONTENT DENSITY LIMIT INDEX SWELL* PRESSURE PRESSURE SIEVE SULFATES
BORING (FEET) (%) (PCF) (%) (PSF) (PSF) (%) (%) DESCRIPTION
SWELL TEST RESULTS*
TABLE B-I
SUMMARY OF LABORATORY TESTING
ATTERBERG LIMITS
TH-11 14 13.1 113 -0.2 1,800 CLAYSTONE
TH-11 19 12.5 122 0.6 2,400 5,400 CLAYSTONE
TH-11 24 14.2 124 1.3 3,000 11,000 CLAYSTONE
TH-12 14 23.3 104 -0.4 1,800 CLAY, SANDY (CL)
Page 2 of 2
* NEGATIVE VALUE INDICATES COMPRESSION.
GOODWIN KNIGHT
TRIANGLE DRIVE AND COLLEGE AVENUE DEVELOPMENT
CTL|T PROJECT NO. FC08964-115
APPENDIX C
GUIDELINE SITE GRADING SPECIFICATIONS
GOODWIN KNIGHT
TRIANGLE DRIVE AND COLLEGE AVENUE DEVELOPMENT
CTLT PROJECT NO. FC08964-115
Appendix C-1
GUIDELINE SITE GRADING SPECIFICATIONS
1. DESCRIPTION
This item shall consist of the excavation, transportation, placement and
compaction of materials from locations indicated on the plans, or staked by
the Engineer, as necessary to achieve preliminary street and overlot
elevations. These specifications shall also apply to compaction of excess cut
materials that may be placed outside of the development boundaries.
2. GENERAL
The Soils Engineer shall be the Owner's representative. The Soils Engineer
shall approve fill materials, method of placement, moisture contents and
percent compaction, and shall give written approval of the completed fill.
3. CLEARING JOB SITE
The Contractor shall remove all vegetation and debris before excavation or fill
placement is begun. The Contractor shall dispose of the cleared material to
provide the Owner with a clean, neat appearing job site. Cleared material
shall not be placed in areas to receive fill or where the material will support
structures of any kind.
4. SCARIFYING AREA TO BE FILLED
All topsoil and vegetable matter shall be removed from the ground surface
upon which fill is to be placed. The surface shall then be plowed or scarified
until the surface is free from ruts, hummocks or other uneven features, which
would prevent uniform compaction.
5. COMPACTING AREA TO BE FILLED
After the foundation for the fill has been cleared and scarified, it shall be
disked or bladed until it is free from large clods, brought to the proper moisture
content (0 to 3 percent above optimum moisture content for clays and within 2
percent of optimum moisture content for sands) and compacted to not less
than 95 percent of maximum dry density as determined in accordance with
ASTM D698.
6. FILL MATERIALS
Fill soils shall be free from organics, debris or other deleterious substances,
and shall not contain rocks or lumps having a diameter greater than six (6)
GOODWIN KNIGHT
TRIANGLE DRIVE AND COLLEGE AVENUE DEVELOPMENT
CTLT PROJECT NO. FC08964-115
Appendix C-2
inches. Fill materials shall be obtained from cut areas shown on the plans or
staked in the field by the Engineer.
On-site materials classifying as CL, CH, SC, SM, SW, SP, GP, GC and GM
are acceptable. Concrete, asphalt, organic matter and other deleterious
materials or debris shall not be used as fill.
7. MOISTURE CONTENT AND DENSITY
Fill material shall be moisture conditioned and compacted to the criteria in the
table, below. Maximum density and optimum moisture content shall be
determined from the appropriate Proctor compaction tests. Sufficient
laboratory compaction tests shall be made to determine the optimum moisture
content for the various soils encountered in borrow areas.
TABLE C
FILL COMPACTION AND MOISTURE REQUIREMENTS
Soil
Type
Depth from
Final Grade
(feet)
Moisture Requirement
(% from optimum)
Density Requirement
Clay
0 to 15 feet
0 to +3 95% of ASTM D 698
Sand -2 to +2 95% of ASTM D 698
Clay Greater than 15
feet
-2 to +1 98% of ASTM D 698
Sand -2 to +1 95% of ASTM D 1557
The Contractor may be required to add moisture to the excavation materials in
the borrow area if, in the opinion of the Soils Engineer, it is not possible to
obtain uniform moisture content by adding water on the fill surface. The
Contractor may be required to rake or disc the fill soils to provide uniform
moisture content through the soils.
The application of water to embankment materials shall be made with any
type of watering equipment approved by the Soils Engineer, which will give the
desired results. Water jets from the spreader shall not be directed at the
embankment with such force that fill materials are washed out.
GOODWIN KNIGHT
TRIANGLE DRIVE AND COLLEGE AVENUE DEVELOPMENT
CTLT PROJECT NO. FC08964-115
Appendix C-3
Should too much water be added to any part of the fill, such that the material
is too wet to permit the desired compaction from being obtained, rolling and all
work on that section of the fill shall be delayed until the material has been
allowed to dry to the required moisture content. The Contractor will be
permitted to rework wet material in an approved manner to hasten its drying.
8. COMPACTION OF FILL AREAS
Selected fill material shall be placed and mixed in evenly spread layers. After
each fill layer has been placed, it shall be uniformly compacted to not less
than the specified percentage of maximum density. Fill shall be compacted to
the criteria above. At the option of the Soils Engineer, soils classifying as SW,
GP, GC, or GM may be compacted to 95 percent of maximum density as
determined in accordance with ASTM D 1557 or 70 percent relative density for
cohesionless sand soils. Fill materials shall be placed such that the thickness
of loose materials does not exceed 12 inches and the compacted lift thickness
does not exceed 6 inches.
Compaction as specified above, shall be obtained by the use of sheepsfoot
rollers, multiple-wheel pneumatic-tired rollers, or other equipment approved by
the Engineer for soils classifying as CL, CH, or SC. Granular fill shall be
compacted using vibratory equipment or other equipment approved by the
Soils Engineer. Compaction shall be accomplished while the fill material is at
the specified moisture content. Compaction of each layer shall be continuous
over the entire area. Compaction equipment shall make sufficient trips to
ensure that the required density is obtained.
9. COMPACTION OF SLOPES
Fill slopes shall be compacted by means of sheepsfoot rollers or other
suitable equipment. Compaction operations shall be continued until slopes
are stable, but not too dense for planting, and there is no appreciable amount
of loose soils on the slopes. Compaction of slopes may be done
progressively in increments of three to five feet (3' to 5') in height or after the
fill is brought to its total height. Permanent fill slopes shall not exceed 3:1
(horizontal to vertical).
10. PLACEMENT OF FILL ON NATURAL SLOPES
Where natural slopes are steeper than 20 percent in grade and the placement
of fill is required, benches shall be cut at the rate of one bench for each 5 feet
in height (minimum of two benches). Benches shall be at least 10 feet in
width. Larger bench widths may be required by the Engineer. Fill shall be
placed on completed benches as outlined within this specification.
GOODWIN KNIGHT
TRIANGLE DRIVE AND COLLEGE AVENUE DEVELOPMENT
CTLT PROJECT NO. FC08964-115
Appendix C-4
11. DENSITY TESTS
Field density tests shall be made by the Soils Engineer at locations and
depths of his choosing. Where sheepsfoot rollers are used, the soil may be
disturbed to a depth of several inches. Density tests shall be taken in
compacted material below the disturbed surface. When density tests indicate
that the density or moisture content of any layer of fill or portion thereof is not
within specification, the particular layer or portion shall be reworked until the
required density or moisture content has been achieved.
12. SEASONAL LIMITS
No fill material shall be placed, spread or rolled while it is frozen, thawing, or
during unfavorable weather conditions. When work is interrupted by heavy
precipitation, fill operations shall not be resumed until the Soils Engineer
indicates that the moisture content and density of previously placed materials
are as specified.
13. NOTICE REGARDING START OF GRADING
The Contractor shall submit notification to the Soils Engineer and Owner
advising them of the start of grading operations at least three (3) days in
advance of the starting date. Notification shall also be submitted at least 3
days in advance of any resumption dates when grading operations have been
stopped for any reason other than adverse weather conditions.
14. REPORTING OF FIELD DENSITY TESTS
Density tests made by the Soils Engineer, as specified under "Density Tests"
above, shall be submitted progressively to the Owner. Dry density, moisture
content, and percentage compaction shall be reported for each test taken.
15. DECLARATION REGARDING COMPLETED FILL
The Soils Engineer shall provide a written declaration stating that the site was
filled with acceptable materials and was placed in general accordance with the
specifications.
44/12
50/12
48/12
50/9
50/4
WC=11.9
DD=122
SW=11.5
SS=0.570
WC=12.9
DD=118
SW=3.4
-200=98
WC=13.1
DD=113
SW=-0.2
WC=12.5
DD=122
SW=0.6
WC=14.2
DD=124
SW=1.3
WC=11.9
DD=122
SW=11.5
SS=0.570
WC=12.9
DD=118
SW=3.4
-200=98
WC=13.1
DD=113
SW=-0.2
WC=12.5
DD=122
SW=0.6
WC=14.2
DD=124
SW=1.3
TH-11
El. 5050.1
4/12
7/12
12/12
50/7
50/3
WC=23.3
DD=104
SW=-0.4
WC=23.3
DD=104
SW=-0.4
TH-12
El. 5051.1
DEPTH - FEET
DRIVE SAMPLE. THE SYMBOL 19/12 INDICATES 19 BLOWS OF A 140-POUND HAMMER
FALLING 30 INCHES WERE REQUIRED TO DRIVE A 2.5-INCH O.D. SAMPLER 12 INCHES.
CLAY, SANDY, MOIST TO WET, SOFT TO VERY STIFF, BROWN (CL)
1.
NOTES:
THESE LOGS ARE SUBJECT TO THE EXPLANATIONS, LIMITATIONS AND CONCLUSIONS IN
THIS REPORT.
WATER LEVEL MEASURED SEVERAL DAYS AFTER DRILLING.
WEATHERED CLAYSTONE, SANDY, MOIST, MEDIUM HARD, MOIST, BROWN, GRAY, RUST
4.
LEGEND:
CLAYSTONE, SANDY, MOIST, MEDIUM HARD TO VERY HARD, BROWN, GRAY, RUST
SANDSTONE, CLAYEY, MOIST, HARD, BROWN, GRAY, RUST
DEPTH - FEET
WATER LEVEL MEASURED AT TIME OF DRILLING.
THE BORINGS WERE DRILLED ON JULY 17 AND 24, 2019 USING 4-INCH DIAMETER
CONTINUOUS-FLIGHT AUGERS AND A TRUCK-MOUNTED DRILL RIG.
WC
DD
SW
-200
LL
PI
UC
SS
-
-
-
-
-
-
-
-
INDICATES MOISTURE CONTENT (%).
INDICATES DRY DENSITY (PCF).
INDICATES SWELL WHEN WETTED UNDER OVERBURDEN PRESSURE (%).
INDICATES PASSING NO. 200 SIEVE (%).
INDICATES LIQUID LIMIT.
INDICATES PLASTICITY INDEX.
INDICATES UNCONFINED COMPRESSIVE STRENGTH (PSF).
INDICATES SOLUBLE SULFATE CONTENT (%).
3.
GOODWIN KNIGHT
TRIANGLE DRIVE AND COLLEGE AVENUE DEVELOPMENT
CTL | T PROJECT NO. FC08964-115 FIGURE A-3
Exploratory Borings
Summary Logs of
2. BORING ELEVATIONS WERE SURVEYED AND PROVIDED BY GALLOWAY.
SW=2.4
WC=15.2
DD=118
SW=1.8
TH-6
El. 5059.1
21/12
31/12
50/7
50/9
50/10
WC=11.8
DD=105
LL=44 PI=29
-200=86
WC=15.6
DD=113
SW=5.3
WC=16.7
DD=113
SW=2.8
-200=96
WC=11.8
DD=105
LL=44 PI=29
-200=86
WC=15.6
DD=113
SW=5.3
WC=16.7
DD=113
SW=2.8
-200=96
TH-7
El. 5046.1
15/12
14/12
24/12
50/8
50/7
WC=7.0
DD=88
SW=-2.6
-200=67
WC=9.8
DD=95
SW=0.1
WC=7.6
DD=106
SW=-0.1
WC=14.3
DD=121
SW=3.4
WC=14.1
DD=122
SW=1.3
WC=7.0
DD=88
SW=-2.6
-200=67
WC=9.8
DD=95
SW=0.1
WC=7.6
DD=106
SW=-0.1
WC=14.3
DD=121
SW=3.4
WC=14.1
DD=122
SW=1.3
TH-8
El. 5085.7
DEPTH - FEET
DEPTH - FEET
GOODWIN KNIGHT
TRIANGLE DRIVE AND COLLEGE AVENUE DEVELOPMENT
CTL | T PROJECT NO. FC08964-115
FIGURE A-2
Exploratory Borings
Summary Logs of
DD=98
SW=-1.7
SS=0.030
WC=14.5
DD=121
SW=2.8
-200=98
TH-2
El. 5057.8
37/12
50/10
50/9
50/11
44/12
WC=12.8
DD=120
SW=8.4
-200=97
WC=15.1
DD=114
SW=5.2
WC=17.0
DD=115
SW=4.7
WC=17.3
DD=112
SW=1.6
WC=19.5
DD=110
SW=2.4
WC=12.8
DD=120
SW=8.4
-200=97
WC=15.1
DD=114
SW=5.2
WC=17.0
DD=115
SW=4.7
WC=17.3
DD=112
SW=1.6
WC=19.5
DD=110
SW=2.4
TH-3
El. 5044.6
15/12
13/12
50/12
50/8
50/10
WC=9.9
DD=98
SW=1.4
WC=11.2
DD=128
SW=0.5
WC=9.9
DD=98
SW=1.4
WC=11.2
DD=128
SW=0.5
TH-4
El. 5076.7
DEPTH - FEET
DEPTH - FEET
GOODWIN KNIGHT
TRIANGLE DRIVE AND COLLEGE AVENUE DEVELOPMENT
CTL | T PROJECT NO. FC08964-115
FIGURE A-1
Exploratory Borings
Summary Logs of
40
TRIANGLE DRIVE AND COLLEGE AVENUE DEVELOPMENT
CTL I T PROJECT NO. FC08964-115
FIGURE 5
Estimated Depth
To Groundwater
VICINITY MAP
(FORT COLLINS, COLORADO)
NOT TO SCALE
125' 250'
APPROXIMATE
SCALE: 1" = 250'
0'
TH-6
TH-8
TH-9
TH-10
TH-12
TH-11
HWY 287 / COLLEGE AVE.
HWY 392 / CARPENTER RD.
TRILBY RD.
SHIELDS ST.
SITE
TRIANGLE DR.
LEGEND:
INDICATES APPROXIMATE
LOCATION OF EXPLORATORY
BORING
INDICATES ESTIMATED GROUND
WATER ELEVATION
4848
TH-1
GOODWIN KNIGHT
TRIANGLE DRIVE AND COLLEGE AVENUE DEVELOPMENT
CTL I T PROJECT NO. FC08964-115
FIGURE 4
Estimated Elevation
of Groundwater
VICINITY MAP
(FORT COLLINS, COLORADO)
NOT TO SCALE
125' 250'
APPROXIMATE
SCALE: 1" = 250'
0'
(FORT COLLINS, COLORADO)
NOT TO SCALE
125' 250'
APPROXIMATE
SCALE: 1" = 250'
0'
TH-4 TH-5
TH-6
TH-8
TH-9
TH-10
TH-12
TH-11
TH-3
HWY 287 / COLLEGE AVE.
HWY 392 / CARPENTER RD.
TRILBY RD.
SHIELDS ST.
SITE
TRIANGLE DR.
LEGEND:
INDICATES APPROXIMATE
LOCATION OF EXPLORATORY
BORING
INDICATES ESTIMATED BEDROCK
4848 SURFACE ELEVATION CONTOUR
TH-1
GOODWIN KNIGHT
TRIANGLE DRIVE AND COLLEGE AVENUE DEVELOPMENT
CTL I T PROJECT NO. FC08964-115
FIGURE 2
VICINITY MAP
(FORT COLLINS, COLORADO)
NOT TO SCALE
125' 250'
APPROXIMATE
SCALE: 1" = 250'
0'
Elevation
Estimated Bedrock