A Method for Analyzing Seismic Stability of Unsaturated Soil Slopes

The instability of slopes triggered by earthquake has received much attention recently. In engineering practice, a slope consists of unsaturated and saturated soils. The seismic analysis should consider the dynamic behavior not only of saturated soils but of unsaturated soils. This paper extended the use of the strength reduction FEM to the seismic stability analysis of unsaturated soil slopes. A new procedure based on static and dynamic finite for analyzing unsaturated soil slope seismic stability without considering the change of matric suction under short-term seismic loading was proposed. The seismic stability analysis was validated through numerical simulations selecting the generalized cohesion of unsaturated soil and the internal friction angle of saturated soils as strength parameters. Results show that the convergence of timehistory curves of relative displacement on key points and plastic zone distribution should be considered simultaneously as the dynamic instability criterion of the slope.