Behaviour of Compacted Clayey Silty Sand under Suction-Controlled Ring Shear Testing

Abstract

Assessment of residual shear strength parameters of soils at relatively low net normal stresses and suction states is of critical importance in slope stability analyses that involve potentially shallow failures triggered by rainfall at relatively high degrees of saturation. To date, however, there is limited experimental evidence of soil behaviour under large deformations, and the corresponding residual shear strength properties, for soils subjected to controlled-suction states. In this work, a series of suction-controlled ring shear tests were conducted on statically compacted samples of clayey silty sand. The tests were accomplished in a newly developed servo/suction-controlled ring shear apparatus that is suitable for testing unsaturated soils via axis-translation technique. Results reflect the important role played by matric suction on residual shear strength properties of unsaturated soils.