Shear Strength Features and Soil Water Retention Curve of a Dual Porosity Expansive Silt-Bentonite Mixture

In this paper the bimodal soil water retention curve of a dual porosity silt-bentonite mixture is determined employing vapor equilibrium method and osmotic suction technique and the validity of these approaches is examined against the results from the filter paper technique. Besides, effect of stress state on the suction value is studied employing the filter paper method. Furthermore, shear strength response of the material is evaluated for a wide range of suction values employing the direct shear apparatus. Results of direct shear tests show that the expansive clay behaves like a normal consolidated soil at relatively low suction values, while, its behavior is similar to the heavily over consolidated soils for the high range of suction values.

Keywords:

Shear Strength , Expansive Clay , Soil Water Retention Curve , Dual Porosity