HomeMy WebLinkAboutCENTRE FOR ADVANCED TECHNOLOGY 23RD, LOT 2 OFFICE BUILDING - PDP/FDP - FDP150007 - SUBMITTAL DOCUMENTS - ROUND 1 - GEOTECHNICAL (SOILS) REPORTSUBSURFACE EXPLORATION REPORT
PROPOSED OFFICE BUILDING DEVELOPOMENT
CSURF TRACT A AT THE GROVE
FORT COLLINS, COLORADO
EEC PROJECT NO. 1132061
Prepared for:
CSU/CSURF Real Estate Office
P.O. Box 483
Fort Collins, Colorado 80522
Attn: Mr. Michael “Bo” Brown, LEED A.P. (Bo.Brown@colostate.edu)
Senior Project Manager
Prepared by:
Earth Engineering Consultants, LLC
4396 Greenfield Drive
Windsor, Colorado 80550
4396 GREENFIELD DRIVE
WINDSOR, COLORADO 80550
(970) 545-3908 FAX (970) 663-0282
www.earth-engineering.com
EARTH ENGINEERING
CONSULTANTS, LLC
September 17, 2013
CSU/CSURF Real Estate Office
P.O. Box 483
Fort Collins, Colorado 80522
Attn: Mr. Michael “Bo” Brown, LEED A.P. (Bo.Brown@colostate.edu)
Re: Subsurface Exploration Report
Proposed Office Buildings
CSURF Tract A at The Grove
Fort Collins, Colorado
EEC Project No. 1132061
Mr. Brown:
Enclosed, herewith, are results of the geotechnical subsurface exploration you requested
for office building development on CSURF Tract A at The Grove development in Fort
Collins, Colorado. As a part of this exploration, six (6) soil borings extending to depths
ranging from approximately 15 to 35 feet below present site grades were advanced in the
proposed building areas to develop information on existing subsurface conditions. This
exploration was completed in general accordance with our proposal dated August 9, 2013.
The proposed development parcel has approximately 40 feet of surface elevation
difference from south to north. Subsurface conditions, in particular groundwater
conditions, varied from the upper to lower levels of the site. The subsurface soils
encountered in the upper levels of the site consisted of stiff to very stiff sandy lean clays
with a layer of sand and gravel between depths of approximately 19 to 24 feet in boring B-
1. The lean clay soils showed low potential to swell with increased in moisture content in
laboratory testing at current moisture and density conditions. Groundwater was observed
at a depth on the order of 20 feet below present site grades in the upper area of the site.
We anticipate the proposed lightly loaded office building could be supported on
conventional footing foundation bearing at the natural stiff to very stiff cohesive site soils
in this area of the site. This area of the site also appears suitable for development of a
basement in the office building.
SUBSURFACE EXPLORATION REPORT
PROPOSED OFFICE BUILDING DEVELOPOMENT
CSURF TRACT A AT THE GROVE
FORT COLLINS, COLORADO
EEC PROJECT NO. 1132061
September 17, 2013
INTRODUCTION
The geotechnical subsurface exploration for the proposed development of two (2) office buildings on
CSURF Tract A at The Grove in Fort Collins, Colorado, has been completed. Six (6) soil borings
extending to depths ranging from approximately 15 to 35 feet below present site grades were
advanced on the site to develop information on existing subsurface conditions. Individual boring
logs and a diagram indicating the approximate boring locations are included with this report.
We understand this project involves the development of CSURF Tract A at The Grove for two (2)
future office buildings. Tract A is located immediately west of Centre Avenue at the east end of The
Grove development. A diagram indicating the approximate parcel location is included with this
report.
We understand the proposed office buildings will be one or two story structures with potential
basement construction where possible. Foundation loads for those structures are expected to be light
with continuous wall loads less than 3 kips per lineal foot and column loads less than 100 kips.
Floor loads are expected to be light. Paved drive and parking areas will be constructed adjacent to
the buildings. Small grade changes are anticipated within the individual building areas to develop
subgrade elevations. Greater amounts of cut and fill may be completed on other areas of the site to
develop site grades.
The purpose of this report is to describe the subsurface conditions encountered in the borings,
analyze and evaluate the test data, and provide geotechnical recommendations concerning site
development, design and construction of foundations and support of floor slabs and pavements.
EXPLORATION AND TESTING PROCEDURES
The test boring locations were selected by others established in the field by Earth Engineering
Consultants, LLC (EEC) personnel by pacing and estimating angles from identifiable site features.
Those approximate boring locations are indicated on the attached boring location diagram. The
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EEC Project No. 1132061
September 17, 2013
Page 2
locations of the borings should be considered accurate only to the degree implied by the methods
used to make the field measurements.
The borings were completed using a truck mounted, CME-55 drill rig equipped with a hydraulic
head employed in drilling and sampling operations. The boreholes were advanced using 4-inch
nominal diameter continuous flight augers and samples of the subsurface materials encountered were
obtained using split barrel and California barrel sampling procedures in general accordance with
ASTM Specifications D1586 and D3550, respectively.
In the split barrel and California barrel sampling procedures, standard sampling spoons are advanced
into the ground with a 140-pound hammer falling a distance of 30 inches. The number of blows
required to advance the split barrel and California barrel samplers is recorded and is used to estimate
the in-situ relative density of cohesionless soils and, to a lesser degree of accuracy, the consistency
of cohesive soils and hardness of weathered bedrock. In the California barrel sampling procedure,
relatively undisturbed samples are obtained in removable brass liners. All samples obtained in the
field were sealed and returned to our laboratory for further examination, classification, and testing.
Laboratory moisture content tests were completed on each of the recovered samples. The
unconfined compressive strength of appropriate samples was estimated using a calibrated hand
penetrometer and the dry density of selected samples was determined in the laboratory. Washed
sieve analysis and Atterberg limits tests were completed on selected samples to evaluate the quantity
and plasticity of fines in the subgrades. Swell/consolidation tests were completed on selected
samples to evaluate the soil’s tendency to change volume with variation in moisture content and
load. Results of the outlined tests are indicated on the attached boring logs and summary sheets.
As part of the testing program, all samples were examined in the laboratory and classified in
accordance with the attached General Notes and the Unified Soil Classification System, based on the
soil’s texture and plasticity. The estimated group symbol for the Unified Soil Classification System
is indicated on the boring logs and a brief description of that classification system is included with
this report. Classification of the bedrock was based on visual and tactual observation of disturbed
samples and auger cuttings. Coring and/or petrographic analysis may reveal other rock types.
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EEC Project No. 1132061
September 17, 2013
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SITE AND SUBSURFACE CONDITIONS
Tract A at The Grove is located immediately west of Centre Avenue and south of Prospect Road in
Fort Collins. A diagram indicating the approximate tract location is included with this report.
Approximately a 40 feet fall occurs from south to north across the site with slight surface drainage
also to the west. The south portion of the site had been stripped of topsoil and vegetation at the time
of our field exploration. No evidence of prior building construction was observed at the site by EEC
site personnel.
Based on results of the field borings and laboratory testing, subsurface conditions can be generalized
as follows. Borings B-1, B-2 and B-3 were completed on the upper portion of the site. At those
locations, the subgrade soils encountered consisted of stiff to very stiff sandy lean clays. A portion
of the near surface materials appeared to be possible fill soils extending to maximum depths on the
order of 3 feet below existing site grade. In boring B-1, a zone of sand and gravel was encountered
between depths of approximately 19 to 24 feet. The lean clay subgrade soils showed low potential
to swell with increase in moisture content at current moisture and density conditions.
Groundwater was observed in borings B-1 and B-3 at depths of approximately 20 feet below present
site grades. Free water was not observed in boring B-2. The borings were backfilled upon
completion so that longer term observations of groundwater levels were not obtained.
Borings B-4, B-5 and B-6 were completed in the lower portion of the site. At those locations
topsoil/vegetation was encountered at ground surface. The topsoil/vegetation was underlain by soft
to stiff sandy lean clays to depths of approximately 17 to 22 feet and were underlain by weathered
claystone/siltstone bedrock. The lean clay soils showed low potential to swell with increase in
moisture content at current moisture and density conditions.
Groundwater on the lower portion of this site was observed at depths ranging from approximately 6
to 8 feet below present ground surface. At these locations, the boreholes were backfilled upon
completion so that longer term observations were not completed.
The stratification boundaries indicated on the boring logs represent the approximate locations of
changes in soil and bedrock types. In-situ, the change of material may be gradual and indistinct.
Earth Engineering Consultants, LLC
EEC Project No. 1132061
September 17, 2013
Page 4
Fluctuations in groundwater levels can occur over time depending on variations in hydrologic
conditions and other conditions not apparent at the time of this report. Zones of perched and/or
trapped water can be encountered in more permeable zones in the subgrade soils. The location and
amount of perched and/or trapped water can also vary over time depending on variations in
hydrologic conditions and other conditions not apparent at the time of this report.
ANALYSIS AND RECOMMENDATIONS
South/Upper Site Area
General Conditions
Subgrade soils in the upper areas of the site consist of stiff to very stiff sandy lean clays with low
potential to swell with increase in moisture content. Near surface fill materials on the site will
require care in developing the bearing and subgrade levels to see that site improvements are not
supported on or above unacceptable in-place fill materials. If unacceptable fill materials are
observed within the building or pavement areas, those materials will require removal, reworking and
replacement prior to construction of the overlying improvements.
Foundations
Based on materials observed at the test boring locations, we anticipate the lightly loaded office
buildings could be supported on conventional footing foundations bearing in the near surface stiff to
very stiff sandy lean clay fill. Basement foundations would be supported on similar type soils. For
design of footing foundations bearing in the stiff to very stiff sandy lean clay soils, we recommend
using a net allowable total load soils bearing pressure not to exceed 2,000 psf. The net bearing
pressure refers to the pressure at foundation bearing level in excess of the minimum surrounding
overburden pressure. Total load would include full dead and live load.
Exterior foundations and foundations in unheated areas should be located at least 30 inches below
adjacent exterior grade to provide frost protection. We recommend formed continuous footings have
a minimum width of 16 inches and isolated column foundations have a minimum width of 30 inches.
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EEC Project No. 1132061
September 17, 2013
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No unusual problems are anticipated in completing the excavations required for the construction of
the footing foundations. Care should be taken at the time of construction to see that the footing
foundations are supported on suitable strength natural soils. Soils which are loosened or disturbed
by the construction activities, unacceptable soils or soils which become dry and desiccated or wet
and softened should be removed and replaced or reworked in-place prior to construction of the
footing foundations.
We estimate the long term settlement of the footing foundations designed and constructed as
outlined above would be less than 1-inch.
Below Grade Areas
Perimeter drain systems should be constructed around all below grade areas to intercept any surface
infiltration and reduce the potential to develop hydrostatic loads on the below grade walls. The
perimeter drain systems would generally include perforated metal or plastic pipe placed near
foundation bearing level and sloped uniformly to a sump area where the accumulated water can be
removed without reverse flow into the system. The drain line should be surrounded by at least 6
inches of the draining granular soils and the drain line and/or granular bedding should be surrounded
by a filter fabric to reduce the intrusions of fines in the subgrade.
Below grade walls should be designed for unbalanced lateral earth pressures. Recommendations for
lateral earth pressure calculations are provided subsequently in this report. Basement walls would
typically be designed for at-rest pressures.
Floor Slabs and Pavement Subgrades
Any remaining vegetation and/or topsoil should be removed from the floor slab and pavement areas.
After stripping, completing all cuts and prior to placement of any fill, floor slabs or pavement, we
recommend the in-place soils be scarified to a minimum depth of 9 inches, adjusted in moisture
content and compacted to at least 95% of the materials standard Proctor maximum dry density. We
recommend the moisture content of the scarified soils should be adjusted to be within the range of
2% of standard Proctor optimum moisture content at the time of compaction. Care should be taken
at the time of construction to see that soft or loose in-place fill soils are removed from floor slab and
pavement areas.
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EEC Project No. 1132061
September 17, 2013
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Fill materials required to develop the floor and/or pavement subgrades should consist of approved,
low-volume change fill materials which are free from organic matter and debris. Those soils should
be placed in loose lifts not to exceed 9 inches thick, and adjusted in moisture content and compacted
as outlined for the scarified soils.
After preparation of the subgrades, care should be taken to avoid disturbing the in-place materials.
Care should also be taken to avoid over densification of the cohesive subgrade soils with
construction traffic. Soils which are loosened or disturbed by the construction activities or soils
which become dry and desiccated or wet and softened should be removed and replaced or reworked
in-place prior to placement of the overlying improvements.
North/Lower Area Development
General Considerations
The subgrade soils observed in the borings completed on the north portion of this site encountered
soft to stiff sandy lean clay with a relatively shallow groundwater table. The subgrade soils show
low potential to swell with increase in moisture content; however, the soft soils would be subject to
some consolidation under load. The loading for consolidation could include site grading in addition
to the building loads. If fills are contemplated in this area over 1 or 2 feet, anticipated settlement of
the subgrades as a result of that fill placement should be evaluated for the depth of fill expected. In
addition, we do not anticipate below grade construction would be feasible with the shallow
groundwater table.
Foundations
The near surface subgrade soils are soft to stiff with potential for consolidation. We anticipate very
lightly loaded foundations could be supported on the natural, soft to stiff sandy lean clay soils
although more heavily loaded foundations may require overexcavation and backfill procedures to
develop suitable foundation bearing. As an alternative, post-tension slab-on-grade foundations
could be considered for support of lightly loaded buildings in this area. Drilled piers extending to
the underlying bedrock could be considered to support heavier loads. Recommendations are
Earth Engineering Consultants, LLC
EEC Project No. 1132061
September 17, 2013
Page 7
provided below for lightly loaded conventional footing foundations. Additional recommendations
concerning alternative foundation types can be provided upon request.
We recommend footing foundations for support of lightly loaded structures be extended through any
existing vegetation and/or topsoil and bear in stiff sandy lean clays. Care will be necessary at the
time of construction to see that soft soils are not present immediately beneath the foundations. If
those soft soils are observed, overexcavation and backfill procedures may be necessary to develop
foundation bearing. We recommend footing foundations for the lightly loaded foundations be sized
using a maximum net allowable bearing pressure of 1,500 psf. The net bearing pressure refers to the
pressure at foundation bearing level in excess of the minimum surrounding overburden pressure.
At the time of construction, care should be taken to carefully evaluate all proposed foundation
bearing materials. Care should also be taken at the time of construction to avoid disturbing
acceptable subgrade materials. Any materials which become which are loosened or disturbed or
soils which become dry and desiccated or wet and softened should be removed and replaced prior to
construction of the overlying footings.
Exterior foundations and foundations in unheated areas should be located at least 30 inches below
adjacent exterior grade to provide frost protection. We recommend formed continuous footings have
a minimum width of 16 inches and isolated column foundations have a minimum width of 30 inches.
We estimate the long term settlement of the footing foundations designed and constructed as
outlined above would be less than 1½ inches.
Floor Slabs and Pavement Subgrades
All existing vegetation and/or topsoil should be removed from floor slab and pavement areas. After
stripping, completing all cuts, we recommend the exposed subgrades be proofrolled with heavy
construction equipment to help locate any soft or loose zones in the near surface subgrades.
Proofrolling should consist of several mutually perpendicular passes over the subgrade with heavily
loaded construction equipment to help locate any soft or loose zones in the near surface subgrades.
Soft or loose zones in the subgrades would be required to removal and replacement prior to
placement of additional fill or overlying improvements.
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EEC Project No. 1132061
September 17, 2013
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After proofrolling, we recommend the exposed subgrades be scarified to a minimum depth of 9
inches, adjusted in moisture content and compacted to at least 95% of the materials maximum dry
density as determined in accordance with ASTM Specification D698, the standard Proctor
procedure. The moisture content of the scarified soils should be adjusted to be within the range of
2% of standard Proctor optimum moisture at the time of compaction.
Fill materials required to develop the pavement and floor slab subgrades should consist of approved,
low-volume change fill materials which are free from organic matter and debris. Those near surface
sandy lean clay soils could be used as fill in these areas. The fill soils should be placed in loose lifts
not to exceed 9 inches thick, and adjusted in moisture content and compacted as recommended for
the scarified soils.
The subgrade soils in the lower areas of the site are soft to stiff with potential to consolidate under
load. Settlement in these areas can be induced with placement of site fills. If fills greater than 1 to 2
feet will be placed in this area, the potential settlement as a result of the fill placement should be
evaluated and addressed.
Care should be taken to avoid disturbing the subgrade soils after preparation as outlined. Soils
which are loosened or disturbed by the construction activities or soils which become dry and
desiccated should be removed and replaced or reworked in-place prior to placement of the overlying
improvements.
General Site Recommendations
Pavement Subgrade
The site subgrade soils consist of lean clays with varying amounts of silt and sand. Those soils are
subject to instability and strength loss when wetted. If pavement construction occurs during wet
period of the year, instability of the subgrades may occur. Stabilization of the pavement subgrades
with Class C fly ash may be necessary to develop a stable subgrade for placement of the overlying
pavements. Additional recommendations concerning stabilization of the pavement subgrades can be
provided as necessary.
Earth Engineering Consultants, LLC
EEC Project No. 1132061
September 17, 2013
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Pavements
We anticipate site pavements will be utilized by low to moderate volumes of light vehicles including
predominately automobiles and light trucks. The subgrades are expected to be comprised of the site
sandy lean clay soils. Those soils have low remolded strength and are relatively poor subgrade
materials for pavements. We recommend the overlying pavements with light traffic include at least
4 inches of hot bituminous pavement (HBP) overlying 6 inches of aggregate base course. The hot
bituminous pavements should be grading S or SX 75 with PG 58-28 or PG 64-22 performance
graded oil. The HBP should be compacted to be within the range of 92 to 96% of maximum
theoretical specific gravity (Rice-value) at the time of placement.
Underlying aggregate base course should consist of Class 5 or Class 6 aggregate base. Those
materials should be placed in loose lifts not to exceed 9 inches thick, adjusted in moisture content
and compacted to at least 95% of standard Proctor maximum dry density.
In areas of the site with significant truck traffic including trash truck routes and loading areas,
consideration should be given to the use of Portland cement concrete pavements. We recommend a
minimum concrete section of 6 inches for heavy duty use areas and trash truck travel areas. The 6-
inch section is based on non-reinforced concrete although fiber mesh or woven wire mesh should be
considered to help control shrinkage cracking. Concrete for use in the pavement should consist of
high quality pavement mix with a minimum 28-day compressive strength of 4,200 psi and air
entrainment.
Fill Placement
We expect site fills will generally be small although some isolated areas of greater fill depths may be
needed. In the lower areas of the site, placement of fills may cause consolidation in the in-situ soft
to stiff cohesive subgrades resulting in surface settlements in this area. In addition, settlement
occurs within placed fill soils with estimated internal settlements on the order of 1% of the height of
the placed fill. The potential for settlement in areas of soft subgrades and within deeper placed fills
should be considered in the site design. Preloading or surcharging can be effective in inducing the
expected settlements prior to construction of overlying improvements. Recommendations for
preloading or surcharging can be provided as appropriate upon request.
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EEC Project No. 1132061
September 17, 2013
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Lateral Earth Pressures
Coefficient values for backfill with anticipated types of soils for calculation of active, at rest and
passive earth pressures are provided in the table below. Equivalent fluid pressure is equal to the
coefficient times the appropriate soil unit weight. As appropriate, buoyant weights and hydrostatic
pressures should be considered. Those coefficient values are based on horizontal backfill with
backfill soils consisting of essentially granular materials with a friction angle of 35 degrees or low
volume change cohesive soils, assuming a friction angle of at least 28 degrees. The assumed values
should be verified with the material supplier or through laboratory testing. For the at-rest and active
earth pressures, slopes away from the structure would result in reduced driving forces with slopes up
away from the structures resulting in greater forces on the walls. The passive resistance would be
reduced with slopes away from the wall. The top 30-inches of soil on the passive resistance side of
walls could be used as a surcharge load; however, should not be used as a part of the passive
resistance value. Frictional resistance is equal to the tangent of the friction angle times the normal
force.
Soil Type On-Site Low Plasticity Cohesive Imported Medium Dense Granular
Wet Unit Weight 120 135
Saturated Unit Weight 130 140
Friction Angle () – (assumed) 28° 35°
Active Pressure Coefficient 0.36 0.27
At-rest Pressure Coefficient 0.53 0.42
Passive Pressure Coefficient 2.77 3.70
Surcharge loads or point loads placed in the backfill can also create additional loads on below grade
walls. Those lateral pressures should be evaluated on an individual basis.
The outlined lateral earth values do not include factors of safety nor allowances for hydrostatic
loads. Care should be taken to develop appropriate drainage systems behind below grade walls to
eliminate potential for hydrostatic loads developing on the walls. Those systems would likely
include perimeter drain systems extending to sump areas or free outfall where reverse flow cannot
Earth Engineering Consultants, LLC
EEC Project No. 1132061
September 17, 2013
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occur into the system. Where necessary, appropriate hydrostatic load values should be used for
design.
GENERAL COMMENTS
The analysis and recommendations presented in this report are based upon the data obtained from
the soil borings performed at the indicated locations and from any other information discussed in this
report. This report does not reflect any variations, which may occur between borings or across the
site. The nature and extent of such variations may not become evident until construction. If
variations appear evident, it will be necessary to re-evaluate the recommendations of this report.
It is recommended that the geotechnical engineer be retained to review the plans and specifications
so comments can be made regarding the interpretation and implementation of our geotechnical
recommendations in the design and specifications. It is further recommended that the geotechnical
engineer be retained for testing and observations during earthwork and foundation construction
phases to help determine that the design requirements are fulfilled.
This report has been prepared for the exclusive use of CSU/CSURF Real Estate, for specific
application to the project discussed and has been prepared in accordance with generally accepted
geotechnical engineering practices. No warranty, express or implied, is made. In the event that any
changes in the nature, design, or location of the project as outlined in this report are planned, the
conclusions and recommendations contained in this report shall not be considered valid unless the
changes are reviewed and the conclusions of this report are modified or verified in writing by the
geotechnical engineer.
DRILLING AND EXPLORATION
DRILLING & SAMPLING SYMBOLS:
SS: Split Spoon - 13/8" I.D., 2" O.D., unless otherwise noted PS: Piston Sample
ST: Thin-Walled Tube - 2" O.D., unless otherwise noted WS: Wash Sample
R: Ring Barrel Sampler - 2.42" I.D., 3" O.D. unless otherwise noted
PA: Power Auger FT: Fish Tail Bit
HA: Hand Auger RB: Rock Bit
DB: Diamond Bit = 4", N, B BS: Bulk Sample
AS: Auger Sample PM: Pressure Meter
HS: Hollow Stem Auger WB: Wash Bore
Standard "N" Penetration: Blows per foot of a 140 pound hammer falling 30 inches on a 2-inch O.D. split spoon, except where noted.
WATER LEVEL MEASUREMENT SYMBOLS:
WL : Water Level WS : While Sampling
WCI: Wet Cave in WD : While Drilling
DCI: Dry Cave in BCR: Before Casing Removal
AB : After Boring ACR: After Casting Removal
Water levels indicated on the boring logs are the levels measured in the borings at the time indicated. In pervious soils, the indicated
levels may reflect the location of ground water. In low permeability soils, the accurate determination of ground water levels is not
possible with only short term observations.
DESCRIPTIVE SOIL CLASSIFICATION
Soil Classification is based on the Unified Soil Classification
system and the ASTM Designations D-2488. Coarse Grained
Soils have move than 50% of their dry weight retained on a #200
sieve; they are described as: boulders, cobbles, gravel or sand.
Fine Grained Soils have less than 50% of their dry weight
retained on a #200 sieve; they are described as : clays, if they
are plastic, and silts if they are slightly plastic or non-plastic.
Major constituents may be added as modifiers and minor
constituents may be added according to the relative proportions
based on grain size. In addition to gradation, coarse grained
soils are defined on the basis of their relative in-place density
and fine grained soils on the basis of their consistency.
Example: Lean clay with sand, trace gravel, stiff (CL); silty
sand, trace gravel, medium dense (SM).
CONSISTENCY OF FINE-GRAINED SOILS
Unconfined Compressive
Strength, Qu, psf Consistency
< 500 Very Soft
500 - 1,000 Soft
1,001 - 2,000 Medium
2,001 - 4,000 Stiff
4,001 - 8,000 Very Stiff
8,001 - 16,000 Very Hard
RELATIVE DENSITY OF COARSE-GRAINED SOILS:
N-Blows/ft Relative Density
0-3 Very Loose
4-9 Loose
10-29 Medium Dense
30-49 Dense
50-80 Very Dense
80 + Extremely Dense
PHYSICAL PROPERTIES OF BEDROCK
DEGREE OF WEATHERING:
Slight Slight decomposition of parent material on
joints. May be color change.
Moderate Some decomposition and color change
throughout.
High Rock highly decomposed, may be extremely
broken.
HARDNESS AND DEGREE OF CEMENTATION:
CSURF – TRACT A AT THE GROVE
FORT COLLINS, COLORADO
EEC PROJECT NO. 1132061
SEPTEMBER 2013
DATE:
RIG TYPE: CME55
FOREMAN: DG
AUGER TYPE: 4" CFA
SPT HAMMER: AUTOMATIC
SOIL DESCRIPTION D N QU MC DD -200
TYPE (FEET) (BLOWS/FT) (PSF) (%) (PCF) LL PI (%) PRESSURE % @ 500 PSF
_ _
SANDY LEAN CLAY (CL) 1
(Possible Fill to 3') _ _
brown / red 2
stiff to very stiff _ _
with traces of gravel 3
_ _
4
_ _
CS 5 10 9000+ 14.3 108.6 39 18 42.9 <500 psf None
_ _
6
_ _
7
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8
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9
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SS 10 6 8500 16.7
_ _
11
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12
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13
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14
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CS 15 8 8000 13.7 116.3
_ _
16
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17
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18
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19
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SS 20 42 -- 10.1
SAND & GRAVEL (SP/GP) _ _
brown 21
medium dense to dense _ _
22
_ _
23
_ _
24
SANDY LEAN CLAY (CL) _ _
brown / tan; stiff to very stiff CS 25 12 4500 20.3 109.0
Continued on Sheet 2 of 2 _ _
Earth Engineering Consultants, LLC
A-LIMITS SWELL
DATE:
RIG TYPE: CME55
FOREMAN: DG
AUGER TYPE: 4" CFA
SPT HAMMER: AUTOMATIC
SOIL DESCRIPTION D N QU MC DD -200
TYPE (FEET) (BLOWS/FT) (PSF) (%) (PCF) LL PI (%) PRESSURE % @ 500 PSF
Continued from Sheet 1 of 2 26
_ _
SANDY LEAN CLAY (CL) 27
brown / tan / rust _ _
stiff to very stiff 28
_ _
29
_ _
SS 30 25 4000 19.8
_ _
31
_ _
32
_ _
33
_ _
34
brown / rust / grey _ _
CS 35 14 2500 20.9 107.7
BOTTOM OF BORING DEPTH 35.0' _ _
36
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37
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38
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39
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40
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41
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42
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43
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44
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46
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47
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48
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49
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50
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Earth Engineering Consultants
A-LIMITS SWELL
N/A
DATE:
RIG TYPE: CME55
FOREMAN: DG
AUGER TYPE: 4" CFA
SPT HAMMER: AUTOMATIC
SOIL DESCRIPTION D N QU MC DD -200
TYPE (FEET) (BLOWS/FT) (PSF) (%) (PCF) LL PI (%) PRESSURE % @ 500 PSF
_ _
SANDY LEAN CLAY (CL) 1
(Possible Fill to ±3') _ _
brown / reddish brown 2
stiff to very stiff _ _ % @ 150 psf
with calcareous deposits & trace gravel CS 3 13 9000+ 13.4 114.3 3200 psf 2.8%
_ _
4
_ _
SS 5 11 9000+ 10.3
_ _
6
_ _
7
_ _
8
_ _
9
_ _ % @ 1000 psf
CS 10 18 9000+ 11.9 124.7 35 22 72.5 1200 psf 0.3%
_ _
11
_ _
12
_ _
13
_ _
14
_ _
SS 15 14 5500 13.9
_ _
16
_ _
17
_ _
18
_ _
19
_ _
CS 20 12 9000+ 17.2 113.2
BOTTOM OF BORING DEPTH 20.0' _ _
21
_ _
22
_ _
23
_ _
24
_ _
25
_ _
Earth Engineering Consultants, LLC
A-LIMITS SWELL
DATE:
RIG TYPE: CME55
FOREMAN: DG
AUGER TYPE: 4" CFA
SPT HAMMER: AUTOMATIC
SOIL DESCRIPTION D N QU MC DD -200
TYPE (FEET) (BLOWS/FT) (PSF) (%) (PCF) LL PI (%) PRESSURE % @ 500 PSF
_ _
SANDY LEAN CLAY (CL) - FILL 1
(Possible Fill Near Surface) _ _
brown / reddish brown 2
stiff to very stiff _ _
3
_ _
4
_ _
CS 5 9 -- 7.8 1050 psf 1.1%
_ _
6
_ _
7
_ _
8
_ _
9
_ _
SS 10 8 3500 14.9
_ _
11
_ _
12
_ _
13
_ _
14
_ _
with traces of coarse sand and gravel CS 15 9 4000 15.0 118.4
_ _
16
_ _
17
_ _
18
_ _
19
_ _
SS 20 10 4000 20.2
_ _
BOTTOM OF BORING DEPTH 20.5' 21
_ _
22
_ _
23
_ _
24
_ _
25
_ _
Earth Engineering Consultants, LLC
A-LIMITS SWELL
DATE:
RIG TYPE: CME55
FOREMAN: DG
AUGER TYPE: 4" CFA
SPT HAMMER: AUTOMATIC
SOIL DESCRIPTION D N QU MC DD -200
TYPE (FEET) (BLOWS/FT) (PSF) (%) (PCF) LL PI (%) PRESSURE % @ 500 PSF
TOPSOIL & VEGETATION _ _
1
SANDY LEAN CLAY (CL) _ _
brown 2
soft to stiff _ _
3
_ _
4
_ _
CS 5 4 -- 18.8 104.3 32 19 63.5 <500 psf None
_ _
6
_ _
7
_ _
8
_ _
9
_ _
SS 10 3 -- 28.8
_ _
11
_ _
12
_ _
13
_ _
14
_ _
LEAN CLAY (CL) CS 15 15 9000 25.5 98.9
brown / grey / rust _ _
very stiff 16
_ _
17
_ _
CLAYSTONE / SILTSTONE 18
brown / grey / rust _ _
soft 19
_ _
SS 20 42 9000+ 21.4
_ _
BOTTOM OF BORING DEPTH 20.5' 21
_ _
22
_ _
23
_ _
24
_ _
25
_ _
Earth Engineering Consultants, LLC
A-LIMITS SWELL
DATE:
RIG TYPE: CME55
FOREMAN: DG
AUGER TYPE: 4" CFA
SPT HAMMER: AUTOMATIC
SOIL DESCRIPTION D N QU MC DD -200
TYPE (FEET) (BLOWS/FT) (PSF) (%) (PCF) LL PI (%) PRESSURE % @ 500 PSF
TOPSOIL & VEGETATION _ _
1
SANDY LEAN CLAY (CL) _ _
dark brown 2
stiff to soft _ _ % @ 150 psf
CS 3 19 9000+ 16.9 112.0 1000 psf 1.2%
_ _
4
_ _
brown SS 5 8 3000 19.3
_ _
6
_ _
7
_ _
8
_ _
9
_ _
CS 10 4 -- 29.5 93.3
_ _
11
_ _
12
_ _
13
_ _
14
brown / reddish brown _ _
SS 15 26 -- 20.2
sand & gravel seam - 15' _ _
16
_ _
17
_ _
18
_ _
19
CLAYSTONE / SILTSTONE _ _
brown / grey / rust, soft CS 20 35 9000+ 22.4 104.3
BOTTOM OF BORING DEPTH 20.0' _ _
21
_ _
22
_ _
23
_ _
24
_ _
25
_ _
Earth Engineering Consultants, LLC
A-LIMITS SWELL
DATE:
RIG TYPE: CME55
FOREMAN: DG
AUGER TYPE: 4" CFA
SPT HAMMER: AUTOMATIC
SOIL DESCRIPTION D N QU MC DD -200
TYPE (FEET) (BLOWS/FT) (PSF) (%) (PCF) LL PI (%) PRESSURE % @ 500 PSF
TOPSOIL & VEGETATION _ _
1
SANDY LEAN CLAY (CL) _ _
dark brown 2
stiff to soft _ _ % @ 150 psf
CS 3 11 7500 16.3 113.6 35 19 68.6 1000 psf 0.8%
_ _
4
_ _
SS 5 8 9000+ 14.1
_ _
6
_ _
7
_ _
8
_ _
9
_ _
CS 10 2 -- 29.5 88.4 <500 psf None
_ _
LEAN CLAY (CL) 11
dark brown _ _
stiff to soft 12
_ _
13
_ _
14
_ _
brown / red / grey SS 15 5 -- 23.5
sand & gravel seams _ _
16
_ _
17
_ _
18
_ _
19
_ _
CS 20 25 9000+ 18.9 113.4
_ _
21
_ _
22
_ _
CLAYSTONE / SILTSTONE 23
grey _ _
moderately hard 24
_ _
SS 25 50/7" 9000+ 17.8
Continued on Sheet 2 of 2 _ _
Earth Engineering Consultants, LLC
A-LIMITS SWELL
DATE:
RIG TYPE: CME55
FOREMAN: DG
AUGER TYPE: 4" CFA
SPT HAMMER: AUTOMATIC
SOIL DESCRIPTION D N QU MC DD -200
TYPE (FEET) (BLOWS/FT) (PSF) (%) (PCF) LL PI (%) PRESSURE % @ 500 PSF
Continued from Sheet 1 of 2 26
_ _
CLAYSTONE / SILTSTONE 27
grey _ _
moderately hard 28
_ _
29
_ _
SS 30 50/3" 9000 10.7 139.0
_ _
31
_ _
32
_ _
33
_ _
34
_ _
SS 35 50/4" 9000 17.0
_ _
BOTTOM OF BORING DEPTH 35.5' 36
_ _
37
_ _
38
_ _
39
_ _
40
_ _
41
_ _
42
_ _
43
_ _
44
_ _
45
_ _
46
_ _
47
_ _
48
_ _
49
_ _
50
_ _
Earth Engineering Consultants
A-LIMITS SWELL
N/A
Project:
Location:
Project #:
Date:
SWELL / CONSOLIDATION TEST RESULTS
Material Description: Brown / Red Sandy Lean Clay (CL)
Sample Location: Boring 1, Sample 1, Depth 4'
Liquid Limit: 39 Plasticity Index: 18 % Passing #200: 42.9%
Beginning Moisture: 14.3% Dry Density: 109.5 pcf Ending Moisture: 18.5%
Swell Pressure: <500 psf % Swell @ 500: None
CSURF - Tract A at The Grove
Fort Collins, Colorado
1132061
September 2013
-10.0
-8.0
-6.0
-4.0
-2.0
0.0
2.0
4.0
6.0
8.0
10.0
0.01 0.1 1 10
Percent Movement
Load (TSF)
Consolidatio Swell
Water Added
Project:
Location:
Project #:
Date:
SWELL / CONSOLIDATION TEST RESULTS
Material Description: Brown Sandy Lean Clay (CL)
Sample Location: Boring 2, Sample 1, Depth 2'
Liquid Limit: - - Plasticity Index: - - % Passing #200: - -
Beginning Moisture: 13.4% Dry Density: 122.3 pcf Ending Moisture: 16.7%
Swell Pressure: 3200 psf % Swell @ 150: 2.8%
CSURF - Tract A at The Grove
Fort Collins, Colorado
1132061
September 2013
-10.0
-8.0
-6.0
-4.0
-2.0
0.0
2.0
4.0
6.0
8.0
10.0
0.01 0.1 1 10
Percent Movement
Load (TSF)
Consolidatio Swell
Water Added
Project:
Location:
Project #:
Date:
CSURF - Tract A at The Grove
Fort Collins, Colorado
1132061
September 2013
Beginning Moisture: 11.9% Dry Density: 127.3 pcf Ending Moisture: 11.9%
Swell Pressure: 1200 psf % Swell @ 1000: 0.3%
Sample Location: Boring 2, Sample 3, Depth 9'
Liquid Limit: 35 Plasticity Index: 22 % Passing #200: 72.5%
SWELL / CONSOLIDATION TEST RESULTS
Material Description: Brown Sandy Lean Clay (CL)
-10.0
-8.0
-6.0
-4.0
-2.0
0.0
2.0
4.0
6.0
8.0
10.0
0.01 0.1 1 10
Percent Movement
Load (TSF)
Consolidatio Swell
Water Added
Project:
Location:
Project #:
Date:
SWELL / CONSOLIDATION TEST RESULTS
Material Description: Brown / Red Sandy Lean Clay (CL)
Sample Location: Boring 3, Sample 1, Depth 4'
Liquid Limit: - - Plasticity Index: - - % Passing #200: - -
Beginning Moisture: 7.8% Dry Density: 106.7 pcf Ending Moisture: 18.8%
Swell Pressure: 1050 psf % Swell @ 500: 1.1%
CSURF - Tract A at The Grove
Fort Collins, Colorado
1132061
September 2013
-10.0
-8.0
-6.0
-4.0
-2.0
0.0
2.0
4.0
6.0
8.0
10.0
0.01 0.1 1 10
Percent Movement
Load (TSF)
Consolidatio Swell
Water Added
Project:
Location:
Project #:
Date:
CSURF - Tract A at The Grove
Fort Collins, Colorado
1132061
September 2013
Beginning Moisture: 9.3% Dry Density: 116.2 pcf Ending Moisture: 20.1%
Swell Pressure: <500 psf % Swell @ 500: None
Sample Location: Boring 4, Sample 1, Depth 4'
Liquid Limit: 32 Plasticity Index: 19 % Passing #200: 63.5%
SWELL / CONSOLIDATION TEST RESULTS
Material Description: Brown Sandy Lean Clay (CL)
-10.0
-8.0
-6.0
-4.0
-2.0
0.0
2.0
4.0
6.0
8.0
10.0
0.01 0.1 1 10
Percent Movement
Load (TSF)
Consolidatio Swell
Water Added
Project:
Location:
Project #:
Date:
SWELL / CONSOLIDATION TEST RESULTS
Material Description: Dark Brown Sandy Lean Clay (CL)
Sample Location: Boring 5, Sample 1, Depth 2'
Liquid Limit: - - Plasticity Index: - - % Passing #200: - -
Beginning Moisture: 16.9% Dry Density: 115.1 pcf Ending Moisture: 17.6%
Swell Pressure: 1000 psf % Swell @ 150: 1.2%
CSURF - Tract A at The Grove
Fort Collins, Colorado
1132061
September 2013
-10.0
-8.0
-6.0
-4.0
-2.0
0.0
2.0
4.0
6.0
8.0
10.0
0.01 0.1 1 10
Percent Movement
Load (TSF)
Consolidatio Swell
Water Added
Project:
Location:
Project #:
Date:
CSURF - Tract A at The Grove
Fort Collins, Colorado
1132061
September 2013
Beginning Moisture: 16.3% Dry Density: 114.9 pcf Ending Moisture: 16.6%
Swell Pressure: 1000 psf % Swell @ 150: 0.8%
Sample Location: Boring 6, Sample 1, Depth 2'
Liquid Limit: 35 Plasticity Index: 19 % Passing #200: 68.6%
SWELL / CONSOLIDATION TEST RESULTS
Material Description: Dark Brown Sandy Lean Clay (CL)
-10.0
-8.0
-6.0
-4.0
-2.0
0.0
2.0
4.0
6.0
8.0
10.0
0.01 0.1 1 10
Percent Movement
Load (TSF)
Consolidatio Swell
Water Added
Project:
Location:
Project #:
Date:
SWELL / CONSOLIDATION TEST RESULTS
Material Description: Dark Brown Sandy Lean Clay (CL)
Sample Location: Boring 6, Sample 3, Depth 9'
Liquid Limit: - - Plasticity Index: - - % Passing #200: - -
Beginning Moisture: 29.5% Dry Density: 93.7 pcf Ending Moisture: 25.6%
Swell Pressure: <500 psf % Swell @ 500: None
CSURF - Tract A at The Grove
Fort Collins, Colorado
1132061
September 2013
-10.0
-8.0
-6.0
-4.0
-2.0
0.0
2.0
4.0
6.0
8.0
10.0
0.01 0.1 1 10
Percent Movement
Load (TSF)
Consolidatio Swell
Water Added
6" (152.4 mm)
5" (127 mm)
4" (101.6 mm)
3" (76 mm)
2 1/2" (63 mm)
2" (50 mm)
1 1/2" (37.5 mm)
1" (25 mm)
3/4" (19 mm)
1/2" (12.5 mm)
3/8" (9.5 mm)
No. 4 (4.75 mm)
No. 8 (2.36 mm)
No. 16 (1.18 mm)
No. 30 (600 mm)
No. 40 (425 mm)
No. 50 (300 mm)
No. 100 (150 mm)
No. 200 (75 mm)
Project: CSURF - Tract A at The Grove
Location: Fort Collins, Colorado
Project No: 1132061
Sample ID: B5, S4, 14'
Sample Desc.: Brown / Red Sandy Lean Clay (CL)
Date: September 2013
EARTH ENGINEERING CONSULTANTS, LLC
SUMMARY OF LABORATORY TEST RESULTS
Sieve Analysis (AASHTO T 11 & T 27 / ASTM C 117 & C 136)
Sieve Size Percent Passing
100
100
100
100
100
100
100
94
94
89
62
60
57
51.1
86
79
74
69
65
EARTH ENGINEERING CONSULTANTS, LLC
Summary of Washed Sieve Analysis Tests (ASTM C117 & C136)
Date:
CSURF - Tract A at The Grove
Fort Collins, Colorado
1132061
B5, S4, 14'
Brown / Red Sandy Lean Clay (CL)
September 2013
Project:
Location:
Project No:
Sample ID:
Sample Desc.:
Cobble Silt or Clay
Gravel
Coarse Fine
Sand
Coarse Medium Fine
6"
5"
4"
3"
2.5"
2"
1.5"
1"
3/4"
1/2"
3/8"
No. 4
No. 8
No. 16
No. 30
No. 40
No. 50
No. 100
No. 200
0
10
20
30
40
50
60
70
80
90
100
1000 100 10 1 0.1 0.01
Finer by Weight (%)
Grain Size (mm)
Standard Sieve Size
8/26/2013 AFTER DRILLING N/A
SURFACE ELEV 24 HOUR N/A
FINISH DATE
SHEET 2 OF 2 WATER DEPTH
START DATE 8/26/2012 WHILE DRILLING 8.0'
CSURF - TRACT A AT THE GROVE
FORT COLLINS, COLORADO
PROJECT NO: 1132061 LOG OF BORING B-6 SEPTEMBER 2013
SURFACE ELEV N/A 24 HOUR N/A
FINISH DATE 8/26/2013 AFTER DRILLING N/A
SHEET 1 OF 2 WATER DEPTH
START DATE 8/26/2012 WHILE DRILLING 8.0'
CSURF - TRACT A AT THE GROVE
FORT COLLINS, COLORADO
PROJECT NO: 1132061 LOG OF BORING B-6 SEPTEMBER 2013
SURFACE ELEV N/A 24 HOUR N/A
FINISH DATE 8/26/2013 AFTER DRILLING N/A
SHEET 1 OF 1 WATER DEPTH
START DATE 8/26/2012 WHILE DRILLING 6.0'
CSURF - TRACT A AT THE GROVE
FORT COLLINS, COLORADO
PROJECT NO: 1132061 LOG OF BORING B-5 SEPTEMBER 2013
SURFACE ELEV N/A 24 HOUR N/A
FINISH DATE 8/26/2013 AFTER DRILLING 7.0'
SHEET 1 OF 1 WATER DEPTH
START DATE 8/26/2012 WHILE DRILLING 7.0'
CSURF - TRACT A AT THE GROVE
FORT COLLINS, COLORADO
PROJECT NO: 1132061 LOG OF BORING B-4 SEPTEMBER 2013
SURFACE ELEV N/A 24 HOUR N/A
FINISH DATE 8/30/2013 AFTER DRILLING N/A
SHEET 1 OF 1 WATER DEPTH
START DATE 8/30/2013 WHILE DRILLING 19.5'
CSURF - TRACT A AT THE GROVE
FORT COLLINS, COLORADO
PROJECT NO: 1132061 LOG OF BORING B-3 SEPTEMBER 2013
SURFACE ELEV N/A 24 HOUR N/A
FINISH DATE 8/26/2013 AFTER DRILLING N/A
SHEET 1 OF 1 WATER DEPTH
START DATE 8/26/2012 WHILE DRILLING None
CSURF - TRACT A AT THE GROVE
FORT COLLINS, COLORADO
PROJECT NO: 1132061 LOG OF BORING B-2 SEPTEMBER 2013
8/26/2013 AFTER DRILLING N/A
SURFACE ELEV 24 HOUR N/A
FINISH DATE
SHEET 2 OF 2 WATER DEPTH
START DATE 8/26/2012 WHILE DRILLING 20.0'
CSURF - TRACT A AT THE GROVE
FORT COLLINS, COLORADO
PROJECT NO: 1132061 LOG OF BORING B-1 SEPTEMBER 2013
SURFACE ELEV N/A 24 HOUR N/A
FINISH DATE 8/26/2013 AFTER DRILLING N/A
SHEET 1 OF 2 WATER DEPTH
START DATE 8/26/2012 WHILE DRILLING 20.0'
CSURF - TRACT A AT THE GROVE
FORT COLLINS, COLORADO
PROJECT NO: 1132061 LOG OF BORING B-1 SEPTEMBER 2013
Limestone and Dolomite:
Hard Difficult to scratch with knife.
Moderately Can be scratched easily with knife.
Hard Cannot be scratched with fingernail.
Soft Can be scratched with fingernail.
Shale, Siltstone and Claystone:
Hard Can be scratched easily with knife, cannot be
scratched with fingernail.
Moderately Can be scratched with fingernail.
Hard
Soft Can be easily dented but not molded with
fingers.
Sandstone and Conglomerate:
Well Capable of scratching a knife blade.
Cemented
Cemented Can be scratched with knife.
Poorly Can be broken apart easily with fingers.
Cemented