Classification of Soil.

Classification of Soil

Step A . Pass Soil sample through 75 micron sieve

More than 50 % soil sample retained : Coarse Grained Soil.

More than 50 % soil sample passing : Fine Grained Soil.

Step B. For Coarse Grained Soil.

i ) Pass the soil (retained on 75 micron sieve) through 4.75 mm sieve

More than 50 % soil sample retained : Gravel (G)

More than 50 % soil sample passing : Sand (S)

ii) Check the percent fines in the coarse fraction.

If Fines < 5 % -> Check Uniformity Coefficient and Coefficient of Curvature

Soil will termed as Poorly Graded and Well Graded.

GW, SW, GP, SP.

If Fines > 12 % -> Check the nature of Fines from A -Line as Given below.

Step C. For Fine Grained Soil

i) Check the Clayey Fraction and Silt Fraction based on the Grain Size. Assign the

Prefix C and M Accordingly.

ii) Using Atterberg Limits, Arrive at the Suffix, L, I, H and accordingly assign the

suffiix.

This more or less completes the classification part of the soil. Now We will move towards

the Numericals Part.