Classification of Soils for Engineering Purposes - Soil Properties: Testing, Measurement, and Evaluation - page 154

GROUP
SYMBOL

GROUP NAME

<30% plus No. 200 <15% plus No. 200

15-29% plus No. 200

Lean clay

% sand ≥ % gravel

Lean clay with sand
Lean clay with gravel
Sandy lean clay
Sandy lean clay with gravel
Gravelly lean clay
Gravelly lean clay with sand

PI>7 and plots
on or above
"A" —line

CL

% sand <% gravel
<15% gravel

% sand ≥ % gravel

≥ 30% plus No. 200 ≥ 15% gravel

% sand <% gravel <15% sand

≥ 15% sand

<30% plus No. 200

<15% plus No. 200
15-29% plus No. 200

Silty clay

% sand ≥ % gravel
% sand <% gravel
<15% gravel

Silty clay with sand
Silty clay with gravel
Sandy silty clay
Sandy silty clay with gravel
Gravelly silty clay
Gravelly silty clay with sand

4 ≤ PI ≤ 7 and
plots on or above
"A" —line

CL - ML

Inorganic

% sand ≥ % gravel

≥ 30% plus No. 200

≥ 15% gravel

% sand <% gravel

<15% sand

≥ 15% sand

<30% plus No. 200

<15% plus No. 200
15-29% plus No. 200

Silt

LL<50

% sand ≥ % gravel
% sand <% gravel
<15% gravel

Silt with sand
Silt with gravel
Sandy silt

PI<4 or plots
below "A" —line

ML

% sand ≥ % gravel

≥ 30% plus No. 200

≥ 15% gravel

Sandy silt with gravel
Gravelly silt

% sand <% gravel

<15% sand

≥ 15% sand

Gravelly silt with sand

LL —ovendried
LL —not dried

Organic <0.75

OL

See figure 1b

<30% plus No. 200

<15% plus No. 200
15-29% plus No. 200

Fat clay
Fat clay with sand
Fat clay with gravel

% sand ≥ % gravel
% sand <% gravel
<15% gravel

PI plots on or
above "A" —line

CH

% sand ≥ % gravel

Sandy fat clay
Sandy fat clay with gravel

≥ 30% plus No. 200

≥ 15% gravel

% sand <% gravel

<15% sand Gravelly fat clay

Gravelly fat clay with sand

Inorganic

≥ 15% sand

<30% plus No. 200 <15% plus No. 200

15-29% plus No. 200

Elastic silt
Elastic silt with sand
Elastic silt with gravel
Sandy elastic silt
Sandy elastic silt with gravel
Gravelly elastic silt
Gravelly elastic silt with sand

% sand % gravel

% sand <% gravel
<15% gravel

≥

PI plots below
"A" —line

MH

LL ≥ 50

% sand ≥ % gravel

≥ 30% plus No. 200

≥ 15% gravel

% sand <% gravel

<15% sand

≥ 15% sand

LL —ovendried
LL —not dried

See figure 1b

Organic <0.75

OH

Figure 11-4 Flow Chart for Classifying Fine-Grained Soil (50% or More Passes No. 200 Sieve) [2]