TABLE

1.1

UnifiedSoilClassificationSystem

Division

Description

Group

Symbol

Identification

Laboratory

ClassificationCriteria

More

than

50%

soil

retained

inUS20

0siev

e(0.075

mm)

More

than

50%

retained

inUSNo.4

(4.75mm)

Clean

gravels

GW

Wellgraded

gravels

Cu>

4,1<Cc<3

GP

Poorlygraded

gravels

NotmeetingGW

criteria

Gravel

withfines

GM

Silty

gravel

Falls

below

Alinein

theplasticitych

art,orPIless

than

4

GC

Clayey

gravel

Falls

aboveA

linein

theplasticitych

art,orPIgreater

than

7

More

than

50%

passing

USNo.4

(4.75mm)

Clean

sand

SW

Wellgraded

sand

Cu>

4,1<

Cc<3

SP

Poorlygraded

sand

NotmeetingSW

criteria

San

dwithfines

SM

Silty

sand

Falls

below

Alinein

theplasticitych

art,orPIless

than

4

SC

Clayey

sand

Falls

aboveA

linein

theplasticitych

art,orPIgreater

than

7

More

than

50%

soil

passing

US20

0siev

e(0.075

mm)

Finegrained

soils

(LL<50

)ML

Inorgan

icsilts

withlow

plasticity

CL

Inorgan

icclay

swithlow

plasticity

OL

Organ

icclay

s/silts

withlow

plasticity

Finegrained

soils

(LL>

50)

MH

Inorgan

icsilts

withhigh

plasticity

CH

Inorgan

icclay

swithhigh

plasticity

OH

Organ

icclay

s/silts

withlow

plasticity

Highly

organ

icsoils

Pt

0010203040506070 Plasticity index

2040

6080

100

Liq

uid

lim

it

U-

Line

A-li

ne

CH

or OH

CL

or OL

ML

or OL

MH

or OH

CL

- M

L

Use

theCasagrandePlasticitych

art

shownabove

Concepts and Techniques Used in Foundation Engineering 7