Probabilistic Stability Analysis of Unsaturated Soil Slopes under Rainfall

The paper presents a new insight into the assessment of unsaturated slope stability under rainfall using the probabilistic method. The rainfall infiltration, correlation length of soil properties, and the cross-correlation between different shear strength parameters are taken into consideration to examine its influences on the stability status of spatially variable soil slope. The factor of safety and the failure probability are simultaneously used to estimate the slope. Results show that coarse grained soil slope is influenced most by the short term rainfall with high rainfall intensity, while the fine grained soil slope influenced most by the long term rainfall. There exists a threshold value of rainfall intensity for different type of soil. The slope would suffer the minimum danger as its constructed soil possesses strength parameters with small correlation length and variation coefficient. And in addition, the failure probability grows bigger when the correlation coefficient between the cohesion strength and friction angle increases.