Comparative Study on the Stress-Dilatancy of Xinjiang Loess Under Saturated and Unsaturated Conditions

Abstract

The amount and scale of engineering construction in Xinjiang develop greatly in recent years. A channel slope in north Xinjiang is an infilled project, which is compacted using local loess material. Being different from the structural feature of natural loess, the infilled material needs to be sufficiently compacted. Study on the stress state, deforming feature and failing pattern of the material is important to reveal the slope stability issues. In this study, saturated and unsaturated triaxial shear tests were performed to study the stress-strain relationship and the mobilized shear strength, and to further investigate the dilatancy of the material. Saturated loess and unsaturated loess at three different suction levels were analyzed respectively. The research results are as below: Firstly, the mobilized shear strengths at peak state and at residual state increase with confining stress and suction level. Secondly, the soil dilatancy is affected by matric suction and stress level. The mobilized angle of dilation at peak state increases significantly with matric suction, but decrease with confining stress.