3D stability of unsaturated soil slopes with tension cracks under steady infiltrations

Abstract

SummaryMost classical approaches for evaluating the stability of soil slopes with cracks are performed under two‐dimensional (2D) condition. Three‐dimensional (3D) effect and suction‐induced effect of unsaturated soils are generally neglected in assessing the slope stability. This paper develops a 3D limit analysis method to evaluate the stability of an unsaturated soil slope with tension cracks under steady infiltrations. The boundary‐value problem is formulated based on the 3D rotational failure mechanism by taking the effects of suction, effective unit weight, and tension crack into account. A simplified method is proposed to calculate the work rate of unsaturated soil weight. A layer‐wise summation method is developed based on the divergence theorem to calculate the internal energy dissipation rate. Detailed discussions are conducted to investigate the effects of suction and Poisson's ratio on the stability of unsaturated soil slopes. Examples are given to illustrate the 3D effect, the suction‐induced effect as well as the effects of infiltration and water in cracks on the slope stability.