HomeMy WebLinkAboutHARMONY MARKET 7TH FILING GOLDEN CORRAL - Filed SER-SUBSURFACE EXPLORATION REPORT -SUBSURFACE EXPLORATION REPORT
PROPOSED GOLDEN CORRAL RESTAURANT
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HARMONY MARKET CENTER
FORT COLLINS, COLORADO
EEC PROJECT 1942044
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June 6, 1994
EARTH ENGINEERING
CONSULTANTS, INC.
G C Development Corporation
P.O. Box 29511
Raleigh, North Carolina 27626
Attn: Mr. Bill Kozar
RE: Subsurface Exploration Report
Proposed Golden Corral Restaurant
Harmony Market Center
Fort Collins, Colorado
EEC Project No. 1942044
Mr. Kozar:
Enclosed, herewith, are the results of the subsurface exploration you requested for the referenced
project. In summary, the subsurface soils encountered in the test borings completed as a part
of this exploration consisted of low plasticity cohesive soils with varying amounts of sand and
gravel. Based on the results of the field and laboratory testing it is our opinion these soils could
be used for direct support of the proposed lightly loaded structure on conventional footing
foundations. The near surface soils could also be used for direct support of floor slabs and
pavements. Geotechnical recommendations concerning design and construction of the
foundations and support of floor slab and pavements are presented in the text of the attached
report.
We appreciate the opportunity to be of service to you on this project. If you have any questions
concerning this report, or if we can be of further service to you in any other way, please do not
hesitate to contact us.
Very truly yours,
Earth Engineering Consultants, Inc.
Principal Engineer
cc: (5) Eldon Ward, Cityscape Urban Design
Curtiss U. Palin, P.E.
Principal Engineer
2600 Canton Ct, Suite A Fort Collins, CO 80525
303) 224-1522 FAX 224-4564
SUBSURFACE EXPLORATION REPORT
PROPOSED GOLDEN CORRAL RESTAURANT
HARMONY MARKET CENTER
FORT COLLINS, COLORADO
EEC PROJECT 1942044
INTRODUCTION
The subsurface exploration for the proposed Golden Corral Restaurant to be constructed in the
Harmony Market Center in Fort Collins, Colorado, has been completed. As requested three (3)
soil borings extending to depths of approximately 15 feet below present site grades were
advanced in the proposed building area and two additional borings were advanced to depths of
approximately 5 feet in the proposed pavement areas. Individual boring logs and a diagram
indicating the approximate boring locations are included with this report.
We understand the proposed Golden Corral Restaurant will be constructed south of Harmony
Road between Boardwalk and Lemay Avenues in Fort Collins, Colorado. The proposed
restaurant will be a single story, slab on grade (non basement) structure with plan area of
approximately 10,000 square feet. Foundation loads for the structure are expected to be light
twith continuous wall loads less than 3 kips per lineal foot and individual column loads less than
50 kips. Floor loads will be less than 100 psf. Paved drive and parking areas will be
constructed along with to the new building. We expect those pavement areas will be used
predominately by automobiles and light trucks. We anticipate less than 2 feet of cut and/or fill
1 will be required to develop site grades for the restaurant.
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 design
and construction of foundations and support of floor slabs and pavement.
EXPLORATION AND TESTING PROCEDURES
The boring locations were selected and established in the field by Earth Engineering Consultants,
Inc. (EEC) personnel. The field locations were determined by pacing and estimating angles
from the references indicated on the attached boring location diagram. The locations of the
borings should be considered accurate only to the degree implied by the methods used to make
the field measurements.
Earth Engineering Consultants, Inc.
Proposed Golden Corral Restaurant
June 6, 1994
Page 2
The borings were performed with a truck mounted, rotary type drill rig equipped with a
hydraulic head employed in drilling and sampling operations. The boreholes were advanced
using continuous flight augers and samples of the subsurface materials encountered were
obtained using thin -walled tube and split -barrel sampling procedures in general accordance with
ASTM Specifications D-1587 and D-1586, respectively. In the thin -walled tube sampling
procedure, a thin -walled, seamless steel tube with a sharpened cutting edge is pushed into the
soil with hydraulic pressure to obtain a relatively undisturbed sample of cohesive or moderately
cohesive material. In the split barrel sampling procedure, a standard 2-inch O.D. split -barrel
sampling spoon is driven 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 sampler 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 materials. All samples obtained in the field were sealed
and returned to the laboratory for further examination, classification and testing.
Moisture content tests were completed on each of the recovered samples. In addition, dry
density and unconfined strength tests were completed on appropriate samples.
Swell/consolidation and Atterberg limits tests were also performed on selected samples to
evaluate the potential for the site soils to change volume with variation with moisture content.
Results of the outlined tests are shown on the attached boring logs.
As a part of the testing program, all samples were examined in the laboratory by an engineer
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 shown on the boring logs and a brief description of that
classification system is included with this report.
SITE AND SUBSURFACE CONDITIONS
The proposed Golden Corral Restaurant will be constructed south of Harmony Road, between
Boardwalk and Lemay Avenues in Fort Collins, Colorado. The building site is located to the
east of the Harmony Road entrance into the Harmony Market Center. Surface drainage at this
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Proposed Golden Corral Restaurant
June 6, 1994
Page 3
site is to the south with maximum difference in ground surface elevations across the building
area on the order of 2 feet. The project site is covered with sparse grass and vegetation and
evidence of prior building construction was not observed at the site by our drill crew.
An EEC field geologist was on -site to direct the drilling activities and maintain a written log of
the materials encountered in the boreholes. The field logs were prepared based on visual and
tactual observation of disturbed samples and auger cuttings. Final boring logs included with this
report may contain modifications to the field logs based on the results of laboratory testing and
engineering evaluation. Based on results of the field borings and laboratory testing, subsurface
conditions can be generalized as follows.
Approximately three to six inches of vegetation and/or topsoil was encountered at the surface
at the boring locations. The topsoil/vegetation was underlain by lean clay which contained
varying amounts of sand and/or gravel. The coloration of the cohesive materials ranged from
dark brown to reddish brown. The cohesive soils were generally stiff to very stiff near the
surface and became softer with depth. Those materials extended to the bottom of the borings
at depths ranging from approximately five feet for the borings in the pavement area to fifteen
feet in the building area borings.
The stratification boundaries shown on the boring logs represent the approximate locations of
changes in soil types; in -situ, the transition of materials may be gradual and indistinct.
WATER LEVEL OBSERVATIONS
Observations were made while drilling after completion of the borings to detect the presence and
level of free water. Free water was observed in the building area borings at depths of
approximately 14 feet as the boreholes were advanced. Approximately 24-hours after completion
of the borings, freewater was observed in those open boreholes at depths of approximately 11.5
feet.
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Proposed Golden Corral Restaurant
June 6, 1994
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Longer term observations including the installation of piezometers which are sealed from the
influence of surface water would be required to more accurately evaluate groundwater
conditions. Zones of perched and/or trapped water may be encountered in more permeable
zones in the cohesive materials. The location and amount of perched water and the depth to the
hydrostatic groundwater table can vary over time depending on variations in hydrologic
conditions and other conditions not apparent at the time of this report.
ANALYSIS AND RECOMMENDATIONS
FOUNDATIONS
Based on the materials we observed at the test boring locations, it is our opinion the proposed
lightly loaded building could be supported on conventional footing foundations. We recommend
those foundations extend through all existing vegetation and/or topsoil and bear in the natural,
stiff lean clay with varying amounts of sand and/or gravel materials. For design of the footing
foundations bearing in natural, stiff to very stiff cohesive soils we recommend using a net
allowable total load soil bearing pressure not to exceed 1,500 psf. The net bearing pressure
refers to the pressure at foundation bearing level in excess of the minimum surrounding
overburden pressure; total load includes full dead and live loads.
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 16 inches and isolated column foundations have
a minimum width of 30 inches. Trenched foundations (grade beam foundations) could be used
in near surface cohesive materials. If used, we recommend those foundations have a width of
at least 12-inches.
No unusual problems are anticipated in completing the excavations required for the construction
of footing foundations. Care should be taken during construction to minimize moisture
variations of the bearing materials. Bearing materials which become dry and desiccated or wet
IEarth Engineering Consultants, Inc.
Proposed Golden Corral Restaurant
June 6, 1994
Page 5
and softened should be removed prior to placement of reinforcement steel and foundation
concrete. Disturbed materials should also be removed from beneath the footing foundations.
We estimate the long term settlement of footing foundations designed and constructed as outlined
above would be small, less than 3/4 inch.
FLOOR SLAB AND PAVEMENT SUBGRADES
All existing vegetation and/or topsoil should be removed from beneath floor slab and pavement
areas. After stripping and completing all cuts and prior to placement of any fill, floor
slabs or pavements, 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 material's maximum
dry density as determined in accordance with ASTM Specification D-698, the standard Proctor
iprocedure. The moisture content of cohesive soil subgrades should be adjusted to be within the
range of -1 to +3% of standard Proctor optimum moisture. Occasional zones of high silt
1 content soils were encountered in the subgrade materials. High silt content soils are typically
subject to strength loss and instability when wetted. It may be necessary to maintain the
moisture content of high silt content soils at a lower level to increase the stability of these
materials.
Fill materials which are required to develop the floor slab and pavement subgrades should
consist of approved, low volume change materials, free from organic matter and debris.
Normally, cohesive soils with a liquid limit of 40 or less and plasticity index of 18 or less could
be used for low volume change fill. If granular materials are used, we recommend those soils
contain a minimum of 15 % fines, material passing a #200 sieve. The near surface cohesive soils
encountered on the project site could be used for fill beneath the floor slabs or pavements. Fill
materials beneath floor slabs or pavements should be placed in loose lifts not to exceed 9-inches
thick, adjusted in moisture content as recommended for the scarified soils and compacted to at
least 95 % of the material's standard Proctor maximum dry density.
Earth Engineering Consultants, Inc.
Proposed Golden Corral Restaurant
June 6, 1994
Page 6
Care should be taken after preparation of the subgrades to avoid disturbing the in -place
materials. Care should also be taken to maintain the recommended moisture in the subgrades.
If materials become dry and desiccated or wet and softened, it will be necessary to rework those
materials prior to placement of the floor slabs or pavements. Disturbed materials will also need
to be reworked prior to placement of the pavements or floor slabs.
PAVEMENTS
Based on previous work we have completed in this vicinity with similar soils, we estimate a
Hveem stabilometer R-value of 7 would be appropriate for design of the pavement sections. We
expect traffic on those pavements will consist of low volumes of automobiles and light trucks.
We recommend pavements for the drive and parking areas consist of at least 3-inches of
asphaltic concrete overlying by 6-inches of aggregate base. In automobile parking areas, a
thinner pavement section consisting of 21/2-inches of asphalt over 4-inches of aggregate base
could be considered. The recommended pavement sections are minimums and, as such, periodic
maintenance should be expected.
We recommend asphaltic concrete for use in the pavement areas consist of SC-1 or SC-2 blends
compatible with City of Fort Collins standard criteria. The aggregate base should be compatible
with Colorado Department of Transportation (CDOT) requirements for Class 5 or Class 6 base.
The base materials should be placed and compacted as recommended for fill beneath the
I pavements.
Consideration could be given to stabilization of the pavement subgrades to develop a stronger
pavement subgrade and reduce the required pavement sections. We recommend stabilization of
the subgrades with Class C fly ash be considered. The Class C fly ash could be blended to a
depth of 12-inches with the fly ash stabilized subgrade replacing the aggregate base course. We
would be pleased to provide additional information concerning stabilization of the subgrades if
desired.
Earth Engineering Consultants, Inc.
Proposed Golden Corral Restaurant
June 6, 1994
Page 7
OTHER CONSIDERATIONS
Positive drainage should be developed away from the proposed building and across and away
from the pavement edges. Water allowed to pond adjacent to the building could result in wetting
of bearing soils and floor slab subgrades and result in unacceptable building performance. Water
allowed to pond on or adjacent to the pavements could result in wetting of the pavement
subgrades and premature failure of the pavement section.
Care should be taken in completing on -site excavations to develop stable slopes of the sides of
the excavations. We estimate slopes not steeper than 2 horizontal to 1 vertical would be
relatively stable for short construction in shallow excavations. Longer term excavations or
deeper excavations would require individual consideration.
A portion of the near surface site soils have relatively high silt content. Those materials would
be subject to instability and strength loss when wetted. It will be necessary to closely monitor
the stability and moisture content of the site materials. Placement of high silt content soils at
dryer moisture contents could result in higher stabilities. Stabilization of the pavement subgrades
could also be considered to increase stability.
Although the near surface soils at this site are not high plasticity materials, cohesive soils in
general can experience volume change with fluctuation in moisture content. Large volume
changes would not be expected in the site soils with normal moisture fluctuations. Some small
movements may occur.
1 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
Earth Engineering Consultants, Inc.
Proposed Golden Corral Restaurant
June 6, 1994
Page 8
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 that 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 Golden Corral Restaurant 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 modified or verified in writing by
the geotechnical engineer.
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PROJECT No: 1942044
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GOLDEN CORRAL
FORT COLLINS, COLORADO
DATE: MAY 1994
PROJECT NO: 1942044
LOG OF BORING B-1 SHEET 1 OF 1
WATER DEPTH ELEV
R1G TYPE: TRACK MOUNT CME
START DATE 5/25194 WHILE DRILLING NONE
FOREMAN: SCK
FINISH DATE 5125/94 AFTER DRILLING NONE
AUGER TYPE: 4" CFA
SURFACE ELEV 24 HOUR NIA
SPT HAMMER: MANUAL
p N QU MC DO A -LIMITS -200 SWELL
PRESSURE 500 PSF
TYPE FEET) (BLOWS/FT) (PSF) PCF) LL Pt (%)
4" VEGETATION & TOPSOIL _
DARK BROWN SANDY CLAY (CL),
16.7 105 39 19 68.3 500 pst NONE
SS 16 `6000
moist, medium stiff _ _
RED I BROWN GRAVELLY SANDY
CLAY (CL), moist, medium stiff
RED GRAVELLY SANDY CLAY (CL),
moist, medium stiff Ss 5 9 11.6
BOTTOM OF BORING 5' 6".
10
15
20
CHP
25
Earth Engineering Consultants
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GOLDEN CORRAL
FORT COLLINS, COLORADO
PROJECT NO: 1942044 DATE: MAY 1994
LOG OF BORING B-2 SHEET 1 OF 1
RIG TYPE: TRACK MOUNT
WATER DEPTH ELEV
FOREMAN: SCK START DATE 5125194 WHILE DRILLING
AUGER TYPE: 4" CFA FINISH DATE 5125194 AFTER DRILLING 13' 6"
SPT HAMMER: MANUAL SURFACE ELEV 124 HOUR 11'.52"
SOIL DESCRIPTION
TYPE
D
FEET)
N
BLOWS/FT)
GU
PSF)
MC
1
DO
PCF)
A -LIMITS
LL PI
200
1
SWELL
PRESSURE p 500 PSF
6" VEGETATION & TOPSOIL
DARK BROWN GRAVELLY SANDY
CLAY (CL), moist, medium stiff
SS
5
12 4000 17.7
LIGHT RED GRAVELLY SANDY CLAY (CL),
moist, medium stiff
Es, 11 3000 11.5
10
DEEP RED SANDY CLAY (CL),
moist, medium stiff
ST 450 psi 18.3 101 35 17 53.8 500 psf NONE
BROWN SAND (SP),BROWN SANDY CLAY (CL),
moist, medium stiff
15
MOTTLED LIGHT BROWN I TAN SANDY
CLAY (CL), moist, soft to medium stiff
SS 8 27.4
20
BOTTOM OF BORING 15' 6".
CHP 25
CarUl Engineering wn u.w.
GOLDEN CORRAL
FORT COLLINS, COLORADO
PROJECT NO: 1942044 DATE: MAY 1994
LOG OF BORING B-3 SHEET 1 OF 1
RIG TYPE: TRACK MOUNT CME WATER DEPTH ELEV
FOREMAN: SCK START DATE 5194 WHILE DRILLING 13' 6"
AUGER TYPE: 4" CFA FINISH DATE 5125194 AFTER DRILLING
SPT HAMMER: MANUAL SURFACE ELEV 24 HOUR
SOIL DESCRIPTION
TYPE
D
FEET )
n
BLOWS;FT)
ou
PSF)
Mc Do
PCFI
A -LIMITS 200 SWELL
LL PI PRESSURE x 500PSF
4" VEGETATION 3 TOPSOIL
DARK BROWN GRAVELLY SANDY
CLAY (CL), moist, medium stiff
SS
5
19 13.7 41 22 72.4 0 psf 0.6
LIGHT RED SANDY CLAY (CL),
moist, medium stiff
SS
Deeper Red Color with Depth.
7 3000 13.7
10SS
BROWN SANDY CLAY (CL),
moist, soft to medium stiff
5 23.9
15
MOTTLED BROWN I ORANGE GRAVELLY
SANDY CLAY (CL), moist to wet, soft SS 7 29.2
20
BOTTOM OF BORING 15' 6".
CHP 25
Carpi Engineering \ onsuwuw
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GOLDEN CORRAL
FORT COLLINS, COLORADO
PROJECT NO: 1942044
DATE: MAY 1994
LOG OF BORING B-4 SHEET 1 OF 1
RIG TYPE: TRACK MOUNT CME zii WATER DEPTH ELEV
FOREMAN: SCK START DATE 5125194 WHILE DRILLING 13' 6"
AUGER TYPE: 4" CFA
SPT HAMMER: MANUAL
FINISH DATE
SURFACE ELEV
5125194
24
AFTER DRILLING
HOUR 11'.50"
SOIL DESCRIPTION
TYPE
D
FEET)
N
SLOWSIFT)
OU
PSF)
MC
1%)
DD
PCF)
A -LIMITS
LL Pf
200
I%)
SWELL
PRESSURE I tD 500PSF
4" VEGETATION & TOPSOIL
DARK BROWN GRAVELLY SANDY
CLAY (CL), moist, medium stiff SS
5
19 17.9
LIGHT RED SANDY CLAY (CL),
moist, stiff ESS 6 3000 17.8 38 19 62.1 500 sf NONE
10SS
BROWN SANDY CLAY (CL),
moist to wet, soft
SS
3 1500 25.4
15 5 1500 27.7
20
Faith Fnnineerina COnSUItafItS
BOTTOM OF BORING 15' 6".
CHP 25
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GOLDEN CORRAL
FORT COLLINS, COLORADO
PROJECT NO: 1942044 DATE: MAY 1994
LOG OF BORING B-5 SHEET 1 OF 1
RIG TYPE: TRACK MOUNT CME WATER DEPTH ELEV
FOREMAN: SCK START DATE 5I25/94 WHILE DRILLING NONE
AUGER TYPE: 4" CFA FINISH DATE 5/25/94 AFTER DRILLING NONE
SPT HAMMER: MANUAL SURFACE ELEV 24 HOUR NIA
SOIL DESCRIPTION
TYPE
D
IFEET)
N
SLOWS'FT)
GU
PSF)
MC DO
PCF)
A -LIMITS 200 SWELL
LL PI PRESSURE 500 PSF
5" VEGETATION & TOPSOIL
DARK BROWN GRAVELLY SANDY
CLAY (CL), moist medium stiff
SS
5
18 16.9
LIGHT RED GRAVELLY SANDY
CLAY (CL), moist, soft SS 5 14.1
10
BOTTOM OFBORING 5' 6".
15
20
25
Gdflll CIII uIccl u y v.+u., .+
tDRILLING AND EXPLORATION
DRILLING & SAMPLING SYMBOLS:
SS : Split Spoon - 13e" 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
BS : Bulk SampleDB : Diamond Bit = 4", N, B
AS : Auger Sample PM : Pressure Meter
HS : Hollow Stem Auger DC : Dutch Cone
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.
SYMBOLS: WATER LEVEL MEASUREMENT
WL Water Level WS While Sampling
WCI : Wet Cave in
DCI : Dry Cave in
WD : While Drilling
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 groundwater. In low permeability soils, the accurate determination of groundwater
levels is not possible with only short term observations.
DESCRIPTIVE SOIL CLASSIFICATION PHYSICAL PROPERTIES OF BEDROCK
Soil Classification is based on the Unified Soil Classification DEGREE OF WEATHERING:
system and the ASTM Designations D-2487 and D-2488.
Coarse Grained Soils have more than 50% of their dry Slight Slight decomposition of parent material on
weight retained on a #200 sieve; they are described as: joints. May be color change.
boulders, cobbles, gravel or sand. Fine Grained Soils have
less than 50% of their dry weight retained on a #200 sieve; Moderate Some decomposition and color change
they are described as: clays, if they are plastic, and silts if throughout.
they are slightly plastic or non -plastic. Major constituents
may be added as modifiers and minor constituents may be High Rock highly decomposed, may be extremely
added according to the relative proportions based on grain broken.
size. In addition to gradation, coarse grained soils are
defined on the basis of their relative in -place density and HARDNESS AND DEGREE OF CEMENTATION:
fine grained soils on the basis of their consistency. Limestone and Dolomite:
Example: Lean clay with sand, trace gravel, stiff (CL); silty Hard Difficult to scratch with knife.
sand, trace gravel, medium dense ISM).
Moderately Can be scratched easily with knife,
CONSISTENCY OF FINE-GRAINED SOILS Hard Cannot be scratched with fingernail.
Unconfined Compressive Soft Can be scratched with fingernail.
Strength, Qu, psf Consistency
Shale Siltstone and Claystone:
500 Very Soft Hard Can be scratched easily with knife, cannot
500 - 1,000 Soft be scratched with fingernail.
1,001 - 2,000 Medium
2,001 - 4,000 Stiff Moderately Can be scratched with fingernail.
t 4,001 - 8,000 Very Stiff Hard
8,001 - 16,000 Very Hard
Soft Can be easily dented but not molded with
RELATIVE DENSITY OF COARSE -GRAINED SOILS: fingers.
N-Blowslft Relative Density
0-3 Very Loose Sandstone and Conglomerate:
Loose Well Capable of scratching a knife blade.
4-9
10-29 Medium Dense Cemented
30-49 Dense
50-80 Very Dense Cemented Can be scratched with knife.
80 + Extremely Dense
Poorly Can be broken apart easily with fingers.
Cemented
UNIFIED SOIL CLASSIFICATION SYSTEM
Solt Classification
Criteria for Assigning Group Symbols and Group Names Using Laboratory Tests'
Coarse -Grained Gravels more than Clean Gravels Less
Cu > 4 and 1 < Cc <31
Soils more than 50% of coarse than 5% finest
50% retained on fraction retained on
No. 200 sieve No. 4 sieve Cu < 4 and/or 1 > Cc > 3L
Gravels with Fines
c
more than 12% fines Fines classify as ML or MH
Fines classify as CL or CH
Sands 50% or more Clean Sands Less Cu > 6 and 1 < Cc < 36
of coarse fraction than 5% finesE
passes No. 4 sieve Cu < B and/or 1 > Cc > 3r
Sands with Fines Fines classify as ML or MH
Fine -Grained Soils
50% or more
passes the
No. 200 sieve
more than 12% finest'
Group
Symbol Group Nar1x '
GW Well -graded gravel'
GP Poorly graded gravel`
GM Silty gravei,G,H
GC Clayey gravelFO•"
SW Well -graded sand'
SP Poorly graded sand'
SM Silty sando "•'
Fines Classify as CL or CH SC Clayey sand'
Silts and Clays inorganic PI > 7 and plots on or above "A line' CL Lean claya L"
Liquid limit less
than 50 PI < 4 or plots below "A" line' ML Sitt 'L"
Silts and Clays
Liquid limit 50
or more
organic Liquid limit - oven dried Organic clayKANA
0.75 OL
Liquid limit - not dried Organic sittK'L'ao
inorganic PI plots on or above "A" line CH Fat clay""
PI lots below "A" line MH Elastic Silt'-L'a
organic Liquid limit - oven dried Organic clay'(L"'
0.75 OH
Liquid limit - not dried Organic silt'-L'a•o
Highly organic soils Primarily organic matter, dark in color, and organic odor PT Peat
ABased on the material passing the 3-in. 'If soil contains 15 to 29% plus No. 200, add
75-mm) sieve , sCu=Dao1Dlo Cc . (
D,
o) _ "with sand" or "with gravel", whichever is
elf field sample contained cobbles or D10 x Dco predominant.
boulders, or both, add "with cobbles or
boulders, or both" to group name.
Gravels with 5 to 12% fines require dual 'if soil contains > 15% sand, add "with
symbols: sand" to group name.
GW-GM well -graded gravel with silt If fines classify as CL-ML, use dual symbol
GW-GC well -graded gravel with clay GC -GM, or SC-SM.
GP -GM poorly graded gravel with silt If fines are organic, add "with organic fines"
GP -GC poorly graded gravel with clay to group name.
Sands with 5 to 12% fines require dual If soil contains > 15% gravel, add "with
symbols: gravel" to group name.
SW-SM well -graded sand with silt If Atterberg limits plot in shaded area, soil is
SW -SC well -graded sand with clay a CL-ML, silty clay.
SP-SM poorly graded sand with silt
SP-SC poorly graded sand with clay
60
FZ9
10
r
0
0
Llf soil contains > 30% plus No. 200
predominantly sand, add "sandy" to group
name.
Alf soil contains > 30% plus No. 200,
predominantly gravel, add "gravelly" to group
name.
PI > 4 and plots on or above "A" line.
PI < 4 or plots below "A" line.
PI plots on or above "A" line.
Pl plots below "A" line.
For classification of fine-grained soils
and fine-grained fraction of coarse - X_ grained soils
Equallon of -A- • line
Horizontal at PI . a to LL . 25.5.
then Pi " 0.73 ILL • 20)
Equation of -U- - line -- pF'' ---
Vertical at LL " 16 to PI 7, ,
then PI . 0.9 (LL - 8)
I /
MH OR OH
CL ML MLoROL
I
10 16 20 30 40 50 60 10 so 90 100 110
LIQUID LIMIT (LL)
i
t ii w ti, a I