Failure distribution analysis of shallow landslides under rainfall infiltration based on fragility curves

Abstract

The failure time of slope is essential for slope risk assessment. However, in previous studies, the safety factor and failure probability of slope have been regarded as the main research topic rather than the failure time. In this study, a stochastic failure distribution model related to the slope failure time is proposed. The stochastic failure distribution model based on fragility curves was used to analyze the failure process of shallow landslides under rainfall infiltration. The fragility curve is derived as a function of the intensity-duration of rainfall from the result of a probabilistic analysis, which considers the uncertainties of the hydraulic and mechanical properties of the soil. Then, the failure distribution analysis was performed for various rainfall conditions based on the generated fragility curves. Using the proposed failure distribution model, a chart showing the relationship between rainfall intensity and slope failure time was developed. The relationship is a kind of intensity-duration rainfall threshold for the initiation of shallow landslides. It is based on a probabilistic analysis considering the uncertainty of the soil properties. The proposed probabilistic failure distribution model could be beneficial for analyzing the failure process of hillslopes due to rainfall infiltration, and for predicting the time of landslide occurrence.