Incorporation of soil suction in stress-based slope stability analysis

Abstract

A procedure is developed where stresses from a finite element analysis are incorporated into a limit equilibrium framework to evaluate the stability of unsaturated soil slopes. Based on a known seepage field and pore pressure distribution in the slope, an independent stress-deformation analysis is performed using the Barcelona Basic Model (Alonso et al, 1990 [1]) to calculate the internal stresses in the slope. Subsequently, slip surfaces from the limit equilibrium analysis are introduced using a series of rectangle planes. The maximum and minimum principal stresses at the centre of each plane can be calculated from the internal stresses and they are introduced into the slope stability analysis depending on the stress level relative to the strength of the unsaturated soils. Finally, a parametric study is carried out to show the effect of suction on the calculated factor of safety. © Springer-Verlag Berlin Heidelberg 2013.