Classification of Soils for Engineering Purposes - Soil Properties: Testing, Measurement, and Evaluation - page 155

GROUP SYMBOL

GROUP NAME

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

15-29% plus No. 200

Organic clay
Organic clay with sand
Organic clay with gravel
Sandy organic clay
Sandy organic clay with gravel
Gravelly organic clay
Gravelly organic clay with sand

% sand % gravel

≥

% sand <% gravel
<15% gravel

PI ≥ 4 and plots on
or above "A"—line

% sand % gravel

≥

≥ 30% plus No. 200

≥ 15% gravel

% sand <% gravel

<15% sand

≥ 15% sand

OL

<30% plus No. 200

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

Organic silt
Organic silt with sand
Organic silt with gravel
Sandy organic silt
Sandy organic silt with gravel
Gravelly organic silt
Gravelly organic silt with sand

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

PI<4 or plots
below "A"—line

% sand ≥ % gravel

30% plus No. 200

≥

≥ 15% gravel

% sand <% gravel

<15% sand

≥ 15% sand

<30% plus No. 200

Organic clay
Organic clay with sand
Organic clay with gravel
Sandy organic clay
Sandy organic clay with gravel
Gravelly organic clay
Gravelly organic clay with sand

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

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

Plots on or
above "A"—line

% sand ≥ % gravel

≥ 30% plus No. 200

≥ 15% gravel

% sand <% gravel

<15% sand

≥ 15% sand

<30% plus No. 200 Organic silt

Organic silt with sand
Organic silt with gravel
Sandy organic silt
Sandy organic silt with gravel
Gravelly organic silt
Gravelly organic silt with sand

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

OH

% sand ≥ % gravel
% sand <% gravel
<15% gravel Plots below

"A"—line

% sand ≥ % gravel

≥ 30% plus No. 200

≥ 15% gravel

% sand <% gravel

<15% sand

≥ 15% sand

Figure 11-5 Flow Chart for Classifying Organic Fine-Grained Soil (50% or More Passes No. 200 Sieve)[2]