Fig. 6.22 Relation between effective stress parameter with degree of saturation for the example problem – 6.1

Question – 6.2 A series of shear tests and water retention tests are conducted on unsaturated sand using modified triaxial set-up. The results are tabulated in the following table. Determine the shear strength parameters using Bishop's formulation and obtain a relation between the effective stress parameter and the degree of saturation.

Solution : The strength parameters under saturated condition can be obtained from a single test as the cohesion intercept is zero (sandy soil). The friction angle can be obtained from the Mohr's circle,