HomeMy WebLinkAboutBUENO DRIVE CONDOS - PDP190004 - SUBMITTAL DOCUMENTS - ROUND 1 - GEOTECHNICAL (SOILS) REPORTSUBSURFACE EXPLORATION REPORT
5724 BUENO DRIVE – LOT 13A
FORT COLLINS, COLORADO
EEC PROJECT NO. 1192010
Prepared for:
Barry Van Everen
938 Ptarmigan Run
Loveland, Colorado 80538
Attn: Mr. Barry Van Everen (barry.vaneveren@gmail.com)
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
February 15, 2019
Barry Van Everen
938 Ptarmigan Run
Loveland, Colorado 80538
Attn: Mr. Barry Van Everen (barry.vaneveren@gmail.com)
Re: Subsurface Exploration Report
5724 Bueno Drive – Lot 13A
Fort Collins, Colorado
EEC Project No. 1192010
Mr. Everen:
Enclosed, herewith, are the results of the subsurface exploration completed by Earth Engineering
Consultants, LLC (EEC) for the referenced project. For this exploration, two (2) soil borings
were extended to depths of approximately 15 to 25 feet below existing site grades. This
subsurface exploration was carried out in general accordance with our proposal dated January 22,
2019.
In summary, the subsurface conditions encountered beneath the surficial vegetation/topsoil layer
in the test borings, generally consisted of sandy lean clay transitioning to bedrock at depths of
approximately 9 feet below the ground surface. The sandy lean clay materials were generally
medium stiff to very stiff and exhibited low swell potential at current moisture and density
conditions. Sandstone/siltstone/claystone bedrock was encountered below the sandy lean clay
and extended to the depths explored, approximately 15 to 25 feet below the existing ground
surface. The bedrock was generally highly weathered to moderately hard and exhibited low swell
potential. Groundwater was not encountered in the borings, which had been extended depths of
approximately 15 to 25 feet below the ground surface, at the time of drilling.
Based on the encountered subsurface conditions, in our opinion, the proposed building could be
supported on conventional spread footings bearing on approved undisturbed sandy lean clay soils
and/or approved engineered fill material. Floor slabs could be supported on approved
undisturbed sandy lean clay soils and/or approved engineered fill material. Pavements could be
supported on a 2-foot zone controlled engineered fill material provided the recommendations as
presented in the attached report are adhered to. Fly ash treatment of the pavements could also be
SUBSURFACE EXPLORATION REPORT
5724 BUENO DRIVE – LOT 13A
FORT COLLINS, COLORADO
EEC PROJECT NO. 1192010
February 15, 2019
INTRODUCTION
The geotechnical subsurface exploration for the proposed pre-engineered metal frame building
planned for construction at 5724 Bueno Drive in Fort Collins, Colorado has been completed. To
develop subsurface information in the proposed development area, two (2) soil borings were drilled
to depths of approximately 15 to 25 feet below existing site grades. A diagram indicating the
approximate boring locations is included with this report.
We understand the proposed development consists of an approximately 4,882 square foot pre-
engineered metal frame building having slab-on-grade construction, an approximate 1,470 square
foot building southeast of the main building, and associated pavement improvements. We anticipate
maximum foundations loads will be relatively light to moderate with maximum wall and column
loads less than 4 klf and 100 kips, respectively. Floor loads are expected to be relatively light. We
anticipate pavements would be utilized by low volumes of light duty traffic with areas designated for
low volumes of heavier duty traffic. Small grade changes are expected to develop site grades for the
proposed improvements.
The purpose of this report is to describe the subsurface conditions encountered in the test borings,
analyze and evaluate the field and laboratory test data and provide geotechnical recommendations
concerning design and construction of foundations and floor slabs and support of flatwork and
pavements. Recommended pavement sections are also included.
EXPLORATION AND TESTING PROCEDURES
The test boring locations were selected and established in the field by EEC personnel by pacing and
estimating angles from identifiable site features. The approximate locations of the borings are
shown on the attached boring location diagram. The boring locations should be considered accurate
only to the degree implied by the methods used to make the field measurements.
Earth Engineering Consultants, LLC
EEC Project No. 1192010
February 15, 2019
Page 2
The test borings were advanced 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. 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 by means of 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. In the California barrel sampling procedure, relatively intact 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 with unconfined
compressive strength of appropriate samples estimated using a calibrated hand penetrometer.
Atterberg limits and washed sieve analysis tests were completed on select samples to evaluate the
quantity and plasticity of fines in the subgrades. Swell/consolidation testing was completed on
select samples to evaluate the potential for the subgrade materials to change volume with variation in
moisture content and load. Soluble sulfate tests were completed on selected samples to estimate the
potential for sulfate attack on site cast concrete. 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 general
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.
Earth Engineering Consultants, LLC
EEC Project No. 1192010
February 15, 2019
Page 3
SITE AND SUBSURFACE CONDITIONS
The proposed building development is planned for construction at 5724 Bueno Drive in Fort Collins,
Colorado. The lot is currently undeveloped with topsoil and vegetation observed at the surface of the
borings. Ground surface in this area is relatively flat, with an approximate relief across the site of
about 5 to 10 feet from southwest to northeast.
EEC field personnel were on site during drilling to evaluate the subsurface conditions encountered
and direct the drilling activities. Field logs prepared by EEC site personnel were based on visual and
tactual observation of disturbed samples and auger cuttings. The final boring logs included with this
report may contain modifications to the field logs based on results of laboratory testing and
evaluation. Based on results of the field borings and laboratory testing, subsurface conditions can be
generalized as follows.
From the ground surface, the subgrades underlying the surficial topsoil and vegetation described
previously consisted of sandy lean clay transitioning to bedrock at depths of approximately 9 feet
below the ground surface. The sandy lean clay materials were generally medium stiff to very stiff
and exhibited low swell potential at current moisture and density conditions.
Sandstone/siltstone/claystone bedrock was encountered below the sandy lean clay and extended to
the depths explored, approximately 15 to 25 feet below the existing ground surface. The bedrock
was generally highly weathered to moderately hard and exhibited low swell potential.
The stratification boundaries indicated on the boring logs represent the approximate location of
changes in soil types; in-situ, the transition of materials may be gradual and indistinct.
GROUNDWATER CONDITIONS
Observations were made while drilling and after completion of the borings to detect the presence and
depth to hydrostatic groundwater. At the time of drilling, groundwater was not observed in the
borings to the depths explored of approximately 15 to 25 feet below the ground surface. The borings
were backfilled upon completion of the drilling operations; therefore, subsequent groundwater
measurements were not performed.
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EEC Project No. 1192010
February 15, 2019
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. Longer term monitoring of
water levels in cased wells, which are sealed from the influence of surface water, would be required
to more accurately evaluate fluctuations in groundwater levels at the site. We have typically noted
deepest groundwater levels in late winter and shallowest groundwater levels in mid to late summer.
ANALYSIS AND RECOMMENDATIONS
Swell – Consolidation Test Results
The swell-consolidation test is performed to evaluate the swell or collapse potential of soils to help
determine foundation, floor slab and pavement design criteria. In this test, relatively undisturbed
samples obtained directly from the California sampler are placed in a laboratory apparatus and
inundated with water under a predetermined load. The swell-index is the resulting amount of swell or
collapse after the inundation period expressed as a percent of the sample’s preload/initial thickness.
After the inundation period, additional incremental loads are applied to evaluate the swell pressure
and/or consolidation.
For this assessment, we conducted four (4) swell-consolidation tests on relatively undisturbed soil
samples obtained at various intervals/depths on the site. The swell index values for the in-situ soil
samples analyzed revealed low to moderate swell characteristics as indicated on the attached swell
test summaries. The (+) test results indicate the soil materials swell potential characteristics while
the (-) test results indicate the soils materials collapse/consolidation potential characteristics when
inundated with water. The following table summarizes the swell-consolidation laboratory test
results for samples obtained during our field explorations for the subject site.
Boring
No.
Depth,
ft.
Material Type
Table I - Swell Consolidation Test Results
In-Situ
Moisture
Content, %
Dry Density,
PCF
Inundation
Pressure, psf
Swell Index,
% (+/-)
B-1 4 Sandy Lean Clay (CL) 7.9 98.7 500 (+) 2.4
B-1 14 Sandstone / Siltstone / Claystone 9.5 114.0 1000 (+) 1.5
B-2 2 Sandy Lean Clay (CL) 14.9 110.0 150 (+) 1.6
B-2 9 Sandstone / Siltstone / Claystone 14.0 115.7 500 (+) 2.1
Earth Engineering Consultants, LLC
EEC Project No. 1192010
February 15, 2019
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Colorado Association of Geotechnical Engineers (CAGE) uses the following information to provide
uniformity in terminology between geotechnical engineers to provide a relative correlation of slab
performance risk to measured swell. “The representative percent swell values are not necessarily
measured values; rather, they are a judgment of the swell of the soil and/or bedrock profile likely to
influence slab performance.” Geotechnical engineers use this information to also evaluate the swell
potential risks for foundation performance based on the risk categories.
Table II - Recommended Representative Swell Potential Descriptions and Corresponding
Slab Performance Risk Categories
Slab Performance Risk Category Representative Percent Swell
(500 psf Surcharge)
Representative Percent Swell
(1000 psf Surcharge)
Low 0 to < 3 0 < 2
Moderate 3 to < 5 2 to < 4
High 5 to < 8 4 to < 6
Very High > 8 > 6
Based on the laboratory test results, a majority of the in-situ samples analyzed for this project were
within the low range. The swell potential of the near surface soils in boring B-1 exhibited swell
potential greater than the maximum allowable 2% general criteria for pavements. A swell mitigation
plan consisting of a 2-foot overexcavation and replacement procedure or fly ash treatment should be
implemented on the pavement subgrades consisting of the sandy lean clay soils.
Site Preparation
Prior to placement of any fill and/or improvements, we recommend any existing topsoil, vegetation,
any potential tree roots, undocumented fill, and any unsuitable materials be removed from the
planned development areas. Due to the swell potential above 2% in boring B-1, subgrades below
pavements should be overexcavated to a depth of 2 feet. Alternatively, fly ash treatment of the sandy
lean clay subgrades below pavements could implemented as a swell mitigation plan per the section
titled Pavements.
After removal of all topsoil, vegetation, overexcavation, and removal of unacceptable or unsuitable
subsoils and prior to placement of fill, the exposed soils should be scarified to a depth of 9 inches,
adjusted in moisture content to within ±2% of standard Proctor optimum moisture content and
Earth Engineering Consultants, LLC
EEC Project No. 1192010
February 15, 2019
Page 6
compacted to at least 95% of the material's standard Proctor maximum dry density as determined in
accordance with ASTM Specification D698.
Fill materials used to develop site grades, and for foundation backfill should consist of an approved
low volume change material, in our opinion, soils similar to the site sandy lean clay materials, or
imported granular structural fill material could be used. Imported granular materials should be
graded similarly to a CDOT Class 5, 6 or 7 aggregate base. Fill materials should be placed in loose
lifts not to exceed 9 inches thick, adjusted in moisture content to within ±2% of standard Proctor
optimum moisture content and compacted to at least 95% of the material's standard Proctor
maximum dry density as determined in accordance with ASTM Specification D698.
Care should be exercised after preparation of the subgrades to avoid disturbing the subgrade
materials. Materials which are loosened or disturbed should be reworked prior to placement of
foundations/flatwork.
Footing Foundations
Based on materials observed from the test boring locations, it is our opinion that the proposed
building could be supported on conventional footing foundations bearing on approved natural
undisturbed subsoils or properly placed fill materials, prepared as recommended in the section Site
Preparation. For design of footing foundations bearing on suitable strength subsoils or on properly
placed fill, we recommend using a net allowable total load soil 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 loads should include full dead and live loads. We
also recommend the footings be designed to maintain a minimum dead load of 500 psf, where
practical.
Exterior foundations and foundations in unheated areas should be located a minimum of 30 inches
below adjacent exterior grade to provide frost protection. We recommend formed continuous
footings have a minimum width of 12 inches and isolated column foundations have a minimum
width of 24 inches. Trenched foundations should not be used.
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EEC Project No. 1192010
February 15, 2019
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No unusual problems are anticipated in completing the excavations required for construction of the
footing foundations. Care should be taken during construction to avoid disturbing the foundation
bearing materials. Materials which are loosened or disturbed by the construction activities or
materials which become dry and desiccated or wet and softened should be removed and replaced
prior to placement of foundation concrete. Care should be taken to ensure spread footings are placed
on similar materials in order to provide a uniform bearing strata.
We estimate the long-term settlement of footing foundations designed and constructed as outlined
above would be 1 inch or less.
Floor Slabs and Exterior Flatwork
Subgrades for floor slabs and exterior flatwork should be prepared as outlined in the section Site
Preparation. For structural design of concrete slabs-on-grade, a modulus of subgrade reaction of
100 pounds per cubic inch (pci) could be used for floors supported on approved natural undisturbed
subsoils or properly placed fill materials.
Additional floor slab design and construction recommendations are as follows:
Interior partition walls should be separated/floated from floor slabs to allow for
independent movement.
Positive separations and/or isolation joints should be provided between slabs and all
foundations, columns, and utility lines to allow for independent movement.
Control joints should be provided in slabs to control the location and extent of
cracking.
Interior trench backfill placed beneath slabs should be compacted in a similar manner
as previously described for imported structural fill material.
Floor slabs should not be constructed on frozen subgrade.
Other design and construction considerations as outlined in the ACI Design Manual
should be followed.
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EEC Project No. 1192010
February 15, 2019
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For interior floor slabs, depending on the type of floor covering and adhesive used, those material
manufacturers may require that specific subgrade, capillary break, and/or vapor barrier requirements
be met. The project architect and/or material manufacturers should be consulted with for specific
under slab requirements.
Care should be exercised after development of the floor slab and exterior flatwork subgrades to
prevent disturbance of the in-place materials. Subgrade soils which are loosened or disturbed by
construction activities or soils which become wet and softened or dry and desiccated should be
removed and replaced or reworked in place prior to placement of the overlying slabs.
Seismic
The site soil conditions generally consist of sandy lean clay which extended to the underlying
bedrock at depths of approximately 9 feet. For those site conditions, the International Building
Codes indicates a Seismic Site Classification of D. Drilling to a greater depth could reveal a
different site classification.
Pavements
Pavement subgrades should be prepared as outlined in the section Site Preparation. A swell
mitigation plan consisting of either a 2-foot overexcavation in areas with sandy lean clay below
pavements or fly ash treatment of the subgrades should be implemented.
If fly ash treatment is chosen, we recommend the addition of at least 13% Class C fly ash to the in-
place subgrade materials, based on dry weights. The Class C fly ash should be thoroughly blended
with the in-place soils to a depth of 12 inches below the top of subgrade. The blended materials
should be adjusted to be within ±2% of standard Proctor optimum moisture and compacted to at least
95% of the materials maximum dry density as determined in accordance with the standard Proctor
procedure for stabilized materials (ASTM Specification D558).
We anticipate the site pavements would include areas designated for low volumes of light weight
automobiles (light duty) and areas of higher volumes of light weight automobiles and low volumes
Earth Engineering Consultants, LLC
EEC Project No. 1192010
February 15, 2019
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of trucks (heavy duty). An equivalent daily load application (EDLA) value of 7 was assumed for
light duty areas, and an EDLA of 15 was assumed for heavy duty areas.
Proofrolling and recompacting the subgrade is recommended immediately prior to placement of the
aggregate road base section. Soft or weak areas delineated by the proofrolling operations should be
undercut or stabilized in-place to achieve the appropriate subgrade support. Based on the subsurface
conditions encountered at the site, an assumed R-value of 10 was used in design of the pavement
sections.
Recommended minimum pavement sections are provided below in Table III. HBP sections may
show rutting/distress in truck loading and drive areas; therefore, concrete pavements should be
considered in these areas. The recommended pavement sections are considered minimum; thus,
periodic maintenance should be expected.
Table III - Recommended Minimum Pavement Sections
Automobile Parking Heavy Duty Areas
18-kip EDLA
18-kip ESAL’s
Reliability
Resilient Modulus (R = 10)
PSI Loss
7
51,100
75%
3562 psi
2.5
15
109,500
85%
3562 psi
2.2
Design Structure Number 2.47 2.96
(A) Composite
Hot Bituminous Pavement
Aggregate Base
(Design Structural Number)
4"
7"
(2.53)
5"
7"
(2.97)
(B) Composite with Fly Ash Treated Subgrade
Hot Bituminous Pavement
Aggregate Base
Fly Ash Treated Subgrade
(Design Structure Number)
3-1/2"
6"
10"
(2.70)
4"
7"
10"
(3.03)
(C) PCC (Non-reinforced) 5" 6"
We recommend aggregate base meet a CDOT Class 5 or Class 6 aggregate base. Aggregate base
should be adjusted in moisture content and compacted to achieve a minimum of 95% of standard
Proctor maximum dry density.
Earth Engineering Consultants, LLC
EEC Project No. 1192010
February 15, 2019
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binder. HBP should be compacted to achieve 92 to 96% of the mix’s theoretical maximum specific
gravity (Rice Value).
Portland cement concrete should be an approved exterior pavement mix with a minimum 28-day
compressive strength of 4,500 psi and should be air entrained. Wire mesh or fiber could be considered
to reduce shrinkage cracking.
Longitudinal and transverse joints should be provided as needed in concrete pavements for
expansion/contraction and isolation. The location and extent of joints should be based upon the final
pavement geometry. Sawed joints should be cut in general accordance with ACI recommendations.
All joints should be sealed to prevent entry of foreign material and dowelled where necessary for load
transfer.
Water Soluble Sulfates (SO4)
The water-soluble sulfate (SO4) content of the on-site overburden subsoils, taken during our
subsurface exploration at random locations and intervals are provided below. Based on reported
sulfate content test results, the Class/severity of sulfate exposure for concrete in contact with the on-
site subsoils is provided in this report.
Table IV: Water Soluble Sulfate Test Results
Sample Location Description Soluble Sulfate Content (mg/l)
B-2, S-1, at 2’ Sandy Lean Clay (CL) 250
Based on the results as presented above, ACI 318, Section 4.2 indicates the site sandy lean clay soils
have a moderate risk of sulfate attack on Portland cement concrete, therefore, ACI Class S1
requirements should be followed for concrete placed in the sandy lean clay soils and underlying
bedrock. Foundation concrete should be designed in accordance with the provisions of the ACI
Design Manual, Section 318, Chapter 4.
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EEC Project No. 1192010
February 15, 2019
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Other Considerations
Positive drainage should be developed away from the structure and pavement areas with a minimum
slope of 1 inch per foot for the first 10 feet away from the improvements in landscape areas. Care
should be taken in planning of landscaping (if required) adjacent to the buildings to avoid features
which would pond water adjacent to the foundations or stemwalls. Placement of plants which
require irrigation systems or could result in fluctuations of the moisture content of the subgrade
material should be avoided adjacent to site improvements. Irrigation systems should not be placed
within 5 feet of the perimeter of the buildings and parking areas. Spray heads should be designed
not to spray water on or immediately adjacent to the structures or site pavements. Roof drains
should be designed to discharge at least 5 feet away from the structures and away from the pavement
areas.
Excavations into the on-site sandy lean clay can be expected to stand on relatively steep, temporary
slopes during construction. The individual contractor(s) should be made responsible for designing
and constructing stable, temporary excavations as required to maintain stability of both the
excavation sides and bottom. All excavations should be sloped or shored in the interest of safety
following local and federal regulations, including current OSHA excavation and trench safety
standards.
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 phases to help determine that the
design requirements are fulfilled.
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EEC Project No. 1192010
February 15, 2019
Page 12
This report has been prepared for the exclusive use of Barry Van Everen 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.
Earth Engineering Consultants, LLC
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.
Group
Symbol
Group Name
Cu≥4 and 1<Cc≤3
E
GW Well-graded gravel
F
Cu<4 and/or 1>Cc>3
E
GP Poorly-graded gravel
F
Fines classify as ML or MH GM Silty gravel
G,H
Fines Classify as CL or CH GC Clayey Gravel
F,G,H
Cu≥6 and 1<Cc≤3
E
SW Well-graded sand
I
Cu<6 and/or 1>Cc>3
E
SP Poorly-graded sand
I
Fines classify as ML or MH SM Silty sand
G,H,I
Fines classify as CL or CH SC Clayey sand
G,H,I
inorganic PI>7 and plots on or above "A" Line CL Lean clay
K,L,M
PI<4 or plots below "A" Line ML Silt
K,L,M
organic Liquid Limit - oven dried Organic clay
K,L,M,N
Liquid Limit - not dried Organic silt
K,L,M,O
inorganic PI plots on or above "A" Line CH Fat clay
K,L,M
PI plots below "A" Line MH Elastic Silt
K,L,M
organic Liquid Limit - oven dried Organic clay
K,L,M,P
Liquid Limit - not dried Organic silt
K,L,M,O
Highly organic soils PT Peat
(D30)2
D10 x D60
GW-GM well graded gravel with silt NPI≥4 and plots on or above "A" line.
GW-GC well-graded gravel with clay OPI≤4 or plots below "A" line.
GP-GM poorly-graded gravel with silt PPI plots on or above "A" line.
GP-GC poorly-graded gravel with clay QPI plots below "A" line.
SW-SM well-graded sand with silt
SW-SC well-graded sand with clay
SP-SM poorly graded sand with silt
SP-SC poorly graded sand with clay
Earth Engineering Consultants, LLC
IIf soil contains >15% gravel, add "with gravel" to
group name
JIf Atterberg limits plots shaded area, soil is a CL-
ML, Silty clay
Unified Soil Classification System
1
2
1
2
Boring Location Diagram
5724 Bueno Drive - Lot 13-A - Fort Collins, Colorado
EEC Project Number: 1192010
February 2019
EARTH ENGINEERING CONSULTANTS, LLC
Aroimate Boring
Locations
1
Legend
Site Potos
Potos taen in aroimate
location, in direction o arro
5724 BUENO DRIVE
FORT COLLINS, COLORADO
EEC PROJECT NO. 1192010
FEBRUARY 2019
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
very stiff _ _
with calcareous deposits 3
_ _
4
_ _
CS 5 27 9000+ 7.9 107.3 35 20 65.4 1500 psf 2.4%
_ _
6
_ _
7
_ _
8
_ _
9
_ _
SANDSTONE / SILTSTONE / CLAYSTONE SS 10 25 9000+ 11.9
brown / grey / rust _ _
highly weathered to moderately hard 11
_ _
12
_ _
13
_ _
14
_ _ % @ 1000 psf
CS 15 38 9000+ 9.5 113.2 35 13 48.9 3500 psf 1.5%
_ _
16
_ _
17
_ _
18
_ _
19
_ _
SS 20 50/7" 9000+ 13.8
_ _
21
_ _
22
_ _
23
_ _
24
_ _
CS 25 50/6" 9000+ 11.1 106.3
BOTTOM OF BORING DEPTH 25.0' _ _
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 / olive 2
medium stiff to stiff _ _ % @ 150 psf
CS 3 9 9000 14.9 109.6 800 psf 1.6%
_ _
4
_ _
SS 5 10 9000+ 12.2
_ _
6
_ _
7
_ _
8
_ _
9
_ _
CS 10 17 9000+ 14.0 114.1 35 20 69.1 2500 psf 2.1%
SANDSTONE / SILTSTONE / CLAYSTONE _ _
brown / grey / rust 11
highly weathered _ _
12
_ _
13
_ _
14
_ _
SS 15 22 5000 14.8
_ _
BOTTOM OF BORING DEPTH 15.5' 16
_ _
17
_ _
18
_ _
19
_ _
20
_ _
21
_ _
22
_ _
23
_ _
24
_ _
25
_ _
Earth Engineering Consultants, LLC
A-LIMITS SWELL
Project:
Location:
Project #:
Date:
5724 Bueno Drive - Lot 13A
Fort Collins, Colorado
1192010
February 2019
Beginning Moisture: 7.9% Dry Density: 98.7 pcf Ending Moisture: 24.0%
Swell Pressure: 1500 psf % Swell @ 500: 2.4%
Sample Location: Boring 1, Sample 1, Depth 4'
Liquid Limit: 35 Plasticity Index: 20 % Passing #200: 65.4%
SWELL / CONSOLIDATION TEST RESULTS
Material Description: Brown Lean Clay with Sand (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:
5724 Bueno Drive - Lot 13A
Fort Collins, Colorado
1192010
February 2019
Beginning Moisture: 9.5% Dry Density: 114 pcf Ending Moisture: 19.1%
Swell Pressure: 3500 psf % Swell @ 1000: 1.5%
Sample Location: Boring 1, Sample 3, Depth 14'
Liquid Limit: 35 Plasticity Index: 13 % Passing #200: 48.9%
SWELL / CONSOLIDATION TEST RESULTS
Material Description: Brown / Grey / Rust Sandstone / Siltstone / Claystone
-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:
5724 Bueno Drive - Lot 13A
Fort Collins, Colorado
1192010
February 2019
Beginning Moisture: 14.9% Dry Density: 110 pcf Ending Moisture: 17.9%
Swell Pressure: 800 psf % Swell @ 150: 1.6%
Sample Location: Boring 2, Sample 1, Depth 2'
Liquid Limit: - - Plasticity Index: - - % Passing #200: - -
SWELL / CONSOLIDATION TEST RESULTS
Material Description: Brown / Olive 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:
5724 Bueno Drive - Lot 13A
Fort Collins, Colorado
1192010
February 2019
Beginning Moisture: 14.0% Dry Density: 115.7 pcf Ending Moisture: 19.5%
Swell Pressure: 3000 psf % Swell @ 500: 2.1%
Sample Location: Boring 2, Sample 3, Depth 9'
Liquid Limit: 35 Plasticity Index: 20 % Passing #200: 69.1%
SWELL / CONSOLIDATION TEST RESULTS
Material Description: Brown / Grey / Rust Sandstone / Siltstone / Claystone
-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
SURFACE ELEV N/A 24 HOUR N/A
FINISH DATE 2/5/2019 AFTER DRILLING N/A
SHEET 1 OF 1 WATER DEPTH
START DATE 2/5/2019 WHILE DRILLING None
5724 BUENO DRIVE - LOT 13A
FORT COLLINS, COLORADO
PROJECT NO: 1192010 LOG OF BORING B-2 FEBRUARY 2019
SURFACE ELEV N/A 24 HOUR N/A
FINISH DATE 2/5/2019 AFTER DRILLING N/A
SHEET 1 OF 1 WATER DEPTH
START DATE 2/5/2019 WHILE DRILLING None
5724 BUENO DRIVE - LOT 13A
FORT COLLINS, COLORADO
PROJECT NO: 1192010 LOG OF BORING B-1 FEBRUARY 2019
Soil Classification
Criteria for Assigning Group Symbols and Group Names Using Laboratory Tests
Sands 50% or more
coarse fraction
passes No. 4 sieve
Fine-Grained Soils
50% or more passes
the No. 200 sieve
<0.75 OL
Gravels with Fines
more than 12%
fines
Clean Sands Less
than 5% fines
Sands with Fines
more than 12%
fines
Clean Gravels Less
than 5% fines
Gravels more than
50% of coarse
fraction retained on
No. 4 sieve
Coarse - Grained Soils
more than 50%
retained on No. 200
sieve
CGravels with 5 to 12% fines required dual symbols:
Kif soil contains 15 to 29% plus No. 200, add "with sand"
or "with gravel", whichever is predominant.
<0.75 OH
Primarily organic matter, dark in color, and organic odor
ABased on the material passing the 3-in. (75-mm)
sieve
ECu=D60/D10 Cc=
HIf fines are organic, add "with organic fines" to
group name
LIf soil contains ≥ 30% plus No. 200 predominantly sand,
add "sandy" to group name.
MIf soil contains ≥30% plus No. 200 predominantly gravel,
add "gravelly" to group name.
DSands with 5 to 12% fines require dual symbols:
BIf field sample contained cobbles or boulders, or
both, add "with cobbles or boulders, or both" to
group name. FIf soil contains ≥15% sand, add "with sand" to
GIf fines classify as CL-ML, use dual symbol GC-
CM, or SC-SM.
Silts and Clays
Liquid Limit less
than 50
Silts and Clays
Liquid Limit 50 or
more
0
10
20
30
40
50
60
0 10 20 30 40 50 60 70 80 90 100 110
PLASTICITY INDEX (PI)
LIQUID LIMIT (LL)
ML OR OL
MH OR OH
For Classification of fine-grained soils and
fine-grained fraction of coarse-grained
soils.
Equation of "A"-line
Horizontal at PI=4 to LL=25.5
then PI-0.73 (LL-20)
Equation of "U"-line
Vertical at LL=16 to PI-7,
then PI=0.9 (LL-8)
CL-ML
HARDNESS AND DEGREE OF CEMENTATION:
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
HBP should be graded as SX or S and be prepared with 75 gyrations using a Superpave gyratory
compactor in accordance with CDOT standards. The HBP should consist of PG 64-22 asphalt