Soil Parameter

Soil Properties

The design for foundation and ELS works require some soil parameter like c’ (cohesion) and f’ (angle of shearing resistance) .

The soil parameters could be determined by triaxial compression test of soil sample obtained in ground investigation work.

Mohr’s Circle Diagram for different soil sample shall be as follow:

The triangles formed by the Mohr’s Circle shall be similar.

i.e q_i / (p_i + c’/tan f') = sin f’= constant
or q_i = p_i sin f’+ c’ cos f’

Hence, for same type of soil, a "p-q" graph can be plotted based on the laboratory test result, where p = (s₁ + s₃)/2 and q = (s₁ - s₃)/2.

We could then obtain the best fit curve for the data in form of q_i = mp_i + b. The soil parameters are then determined by f’= sin^-1 m and c’ = b/ cos f’