Geotechnical Engineering

DHARM

106 GEOTECHNICAL ENGINEERING

Fig. 4.5

Flow chart for classification of coarse-grained soils

COARSE-GRAINED SOILS50% or less pass 75- is sieve

m

Run sieve analysis

GRAVEL (G)

More than 50% of coarse fraction

retained on 4.75 mm IS sieve

SAND (S)

More than 50% of coarse fractionfraction pass 4.75 mm IS sieve

Less than 5% pass

75- IS sieve

m

Between 5% & 12%pass 75- IS sieve

m

More than 12% pass

75- IS sieve

m

Less than 5%

pass 75- IS sieve

m

Examine

grain-size curve

Run w and won minus 425-IS sieve fraction

Lp

m

Examine

grain-size curve

Border line to have double

symbol, appropriate to gradingand plasticity characteristics

Wellgraded

Poorlygraded GP

GW

GM

GM–GC

GC

SW

SP

SM

SM–SC

SC

Below A-line orhatched zone onplasticity chart

Limits plot inhatched zone ofplasticity chart

Above A-line &hatched zone inplasticity chart

Above A-line &hatched zone inplasticity chart

Wellgraded

Poorlygraded

Below A-line orhatched zone onplasticity chart

Limits plot inhatched zone ofplasticity chart

More than 12% passpass 75- IS sieve

m

Run

and

on minus 425-IS sieve fraction

wwLp

m

Border line, to have double

symbol, appropriate to gradingand plasticity characteristics

Between 5% & 12%pass 75- IS sieve

m