Seismic Reliability Assessment of Slopes Reinforced with Antislide Piles under the Action of Random Mainshock–Aftershock Sequences via the PDEM and Newmark Method

Antislide piles are currently applied widely in slope reinforcement engineering, but investigation of the stability of slopes stabilized with this measure under the action of mainshock–aftershock (Ms-As) sequences is very limited. In this study, the probability density evolution method (PDEM) and the Newmark method is adopted to evaluate the reliability of slope reinforced by antislide piles subjected to Ms-As sequences considering the spatial variability of material parameters. Firstly, stochastic Ms-As sequences are generated by combining a physical function model, the Copula function, and the narrowband harmonic group superposition method. In addition, the spectral representation method is taken to generate the random field and the parameters are assigned to the numerical model. Then, the Newmark method is applied to batch-calculate the permanent displacement (Disp) of the slope caused by the Ms-As sequences. The effects of pile position, pile length, and coefficient of variation of cohesion and friction angle (COVC and COVF) on the average value of Disp are discussed. Finally, based on the PDEM, the seismic reliability of the slope strengthened by antislide piles subjected to the Ms-As sequences are obtained. The research results indicate that with the COV increases, the average value of Disp of the slope shows a gradual tendency to increase, and the average value is more sensitive to COVC. Compared with the unreinforced slope, the Disp of the slope strengthened by antislide piles is reduced. The cumulative damage caused by the aftershock and the risk of failure can be significantly reduced by setting a reasonable antislide pile.