Shear Strength of an Unsaturated Silty Soil Subjected to Creep Deformation

Abstract

This study focused on the shear strength of unsaturated soil subjected to creep stress loading for large deformation (i.e. leading to large reduction of matric suction). Solving the practical problems regard to unsaturated soils is considering the properties of unsaturated soil that are subjected to creep progress before occurrence instability of natural slope. This testing program consisted of a creep test and a static compression triaxial test under undrained condition with matric suction control. A silty soil was used and growing of excess pore-water pressure (i.e. reduction of suction) was closely related to large deformation. Effective stress paths of creep behaviour for unsaturated soil were described with that of apparent saturated soil. The failure line was confirmed using effective stress paths of undrained triaxial compression test for apparent saturated soil. Behaviours around the failure line between unsaturated soil subjected to creep stress and apparent saturated soil were discussed and creep failure according to increase of creep stress was possible to interpret using the failure line defined by apparent saturated soil.