Slope stability analysis by considering unsaturated seepage force in unsaturated slope

Abstract

Numerous slope stability analysis methods considering the seepage behavior have been proposed. However, it seems that the consideration of seepage and buoyant forces in unsaturated soil for slope stability analysis on unsaturated slope is insufficient. In this paper, a treatment of seepage and buoyant forces in unsaturated soils is proposed. A volume which affects the seepage force is assumed in order to derive seepage force in unsaturated soil. Janbu’s method with the seepage force is described, and the results of slope stability analysis are presented. The safety factor derived from the Janbu’s method with seepage force in unsaturated soil showed reasonable results. It becomes clear that the consideration of seepage force for slope stability analysis is important. Moreover, a slope stability analysis considered the change in apparent cohesion with the change in degree of saturation is performed. The importance of the consideration of the seepage and buoyant forces in unsaturated soil, and the change in apparent cohesion with the change in degree of saturation are shown.