Soil classification - Geotechnical Investigation and Design Tables - page 21

Figure 2.1 Grading curve.

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Without any laboratory validation test, then any classification is an “opinion''.
Even with confirmatory laboratory testing, then the log is still an interpolation on
validity.

Table 2.7 Unified soil classification (USC) group symbols.

Soil type Description USC symbol

Gravels Well graded GW

Poorly graded GP

Silty GM

Clayey GC

Sands Well graded SW

Poorly graded SP

Silty SM

Inorganic silts Clayey SC

Low plasticity ML

High plasticity MH

Inorganic clays Low plasticity CL

High plasticity CH

Organic with silts/clays of low plasticity OL

with silts/clays of high plasticity OH

Peat Highly organic soils Pt