Instability of unsaturated residual soil slopes due to infiltration

摘要

This paper presents a procedure to calculate a safety factor of the unsaturated slope suffering from the rainfall infiltration. The process of infiltration into a slope due to rainfall and its effect on the behavior of the soil slope are examined by using a two dimensional finite element flwo-deformaiton coupled analysis. The modified Mohr-Coulomb failure criterion is adopted for the strength of the soil to consider the variations of strengths due to the presence of matric suction. A factor of safety is calculated based on the smoothed stress field obtained from finite element method and an optimization tehcnique is used to seearch the critical slip surface. Some numerical examples are analyzed to validate the developed method and to study the effect of hydraulic conductivity on the slope stability during rain-induced infiltration.