Reliability analysis of soil slopes stabilized with piles under rainfall

Reliability analysis of soil slopes under rainfall is an important task for landslide risk assessment. Previous studies rarely contribute to the probabilistic analysis of slope stability under rainfall with reinforcement. A new method is suggested for reliability analysis of soil slopes stabilized with piles under rainfall. First, an efficient numerical model is exploited for slope stability analysis, where two types of slope failure modes, i.e., plastic flow and local failure are considered. To address the blocking effect of piles during seepage analysis, the equivalent hydraulic conductivity of the pile area is estimated according to the effective medium theory. The stabilizing force of piles is investigated by an analytical approach. For saving computational effort, the response surface is established based on a multi-class classification model to predict two types of slope failure modes. Finally, uncertainties in soil parameters and rainfall events are both modelled, and the failure probability of soil slopes within a given time period is assessed through Monte Carlo simulation. An illustrative example is used to demonstrate the performance of the suggested method. It is found that the slope is mainly controlled by local failure. As the pile spacing increases, the likelihood of plastic flow significantly increases. As the piles are located near the slope crest, plastic flow is effectively prevented and the slope is better stabilized against rainfall. If rainfall uncertainties are not considered, the slope failure probability is significantly overestimated. Overall, this study can provide a useful guidance for the design of pile-stabilized slopes against rainfall infiltration.