Classification of Soils for Engineering Purposes - Soil Properties: Testing, Measurement, and Evaluation - page 156

GROUP SYMBOL GROUP NAME

<5% fines

C u ≥ 4 and 1 ≤ C c ≤ 3 <15% sand Well-graded gravel

GW

≥ 15% sand Well-graded gravel with sand

GP

C u <4 and/or 1>C c >3 <15% sand

≥ 15% sand

Poorly graded gravel
Poorly graded gravel with sand

GW - GM <15% sand Well-graded gravel with silt

fines = ML or MH

≥ 15% sand Well-graded gravel with silt and sand

C u ≥ 4 and 1 ≤ C c ≤ 3

fines = CL, CH,
(or CL-ML)

GW - GC <15% sand

≥

Well-graded gravel with clay (or silty clay)
Well-graded gravel with clay and sand
(or silty clay and sand)

15% sand

GRAVEL
% gravel
% sand

>

5-12% fines

<15% sand

fines = ML or MH GP - GM Poorly graded gravel with silt

C u <4 and/or 1>C c >3 ≥ 15% sand

Poorly graded gravel with silt and sand

fines = CL, CH,
(or CL-ML)

GP - GC <15% sand

≥ 15% sand

Poorly graded gravel with clay (or silty clay)
Poorly graded gravel with clay and sand
(or silty clay and sand)

GM <15% sand Silty gravel

fines = ML or MH

Silty gravel with sand

≥ 15% sand

GC

>12% fines fines = CL or CH <15% sand

≥ 15% sand

Clayey gravel
Clayey gravel with sand

GC - GM

fines = CL, ML <15% sand

≥ 15% sand

Silty, clayey gravel
Silty, clayey gravel with sand

<5% fines

C u ≥ 6 and 1 ≤ C c ≤ 3 SW

Well-graded sand

<15% gravel

≥ 15% gravel Well-graded sand with gravel

SP

C u <6 and/or 1>C c >3 <15% gravel

≥ 15% gravel

Poorly graded sand
Poorly graded sand with gravel

Well-graded sand with silt

SW - SM <15% gravel

fines = ML or MH

C u ≥ 6 and 1 ≤ C c ≤ 3 Well-graded sand with silt and gravel

≥ 15% gravel

<15% gravel
≥ 15% gravel

Well-graded sand with clay (or silty clay)
Well-graded sand with clay and gravel
(or silty clay and gravel)

fines = CL, CH,
(or CL-ML)

SW - SC

SAND
% sand

% gravel ≥

5-12% fines

<15% gravel

SP - SM Poorly graded sand with silt

fines = ML or MH

≥ 15% gravel

C u <6 and/or 1>C c >3 Poorly graded sand with silt and gravel

<15% gravel
≥ 15% gravel

SP - SC Poorly graded sand with clay (or silty clay)

Poorly graded sand with clay and gravel
(or silty clay and gravel)

fines = CL, CH,
(or CL-ML)

fines = ML or MH <15% gravel

SM Silty sand

≥ 15% gravel Silty sand with gravel

>12% fines

fines = CL or CH <15% gravel

≥ 15% gravel

SC Clayey sand

Clayey sand with gravel

fines = CL-ML SC - SM <15% gravel

≥ 15% gravel

Silty, clayey sand
Silty, clayey sand with gravel

Figure 11-6 Flow Chart for Classifying Coarse-Grained Soil (More Than 50% Retained on No. 200 Sieve)[2]