Nonlinear energy consumption analysis of multi-stage slope stability subjected to seismic effect and surcharge

Complex loadings often affects multi-stage slopes stability, and the existing stability analysis of multi-stage slopes is mostly based on linear failure criteria, while the failure of rock and soil often presents nonlinear characteristics. In order to analyze the safety performance of multi-stage slopes under different working conditions based on nonlinear characteristics of geotechnical materials in detail, based on the upper bound theorem of limit analysis and strength reduction technique, combined with the nonlinear failure criterion, considering the influence of seismic effect and surcharge, constructing the logarithmic spiral nonlinear energy consumption analysis model of slope. According to the principle of virtual work, the safety factor formula of slope was derived. Using MATLAB optimization calculation and Monte Carlo slope reliability method, combined with slope engineering examples, the influence of nonlinear parameter, seismic effect and surcharge on the stability, potential sliding surface position and reliability index of three-stage slope were discussed. The results show that the slope safety factor decreases significantly with the increase of nonlinear parameter, seismic effect proportional parameter and surcharge. The slope under complex working conditions has a larger range of instability. When nonlinear parameter is lower, the influence of complex loadings on slope stability will be overestimated, which is not conducive to the correct evaluation of its stability. With the increase of nonlinear parameter, surcharge and the decrease of seismic effect, the distance between slope top sliding point and shoulder of the slope gradually increases, the potential sliding surface gradually shifts to the slope, the range of slope instability increases significantly, the reliability index decreases gradually, and the failure probability of the slope increases continuously. When seismic effect and surcharge are larger, the influence of nonlinear parameter on slope stability is more significant. When nonlinear parameter is larger and surcharge is smaller, the influence of seismic effect on slope stability is more significant. When seismic effect is smaller and nonlinear parameter is larger, the influence of surcharge on slope stability is more significant, especially in the stage of 0–20 kPa of surcharge, which should be paid attention to in the design of similar slope engineering. © 2024 Chinese Academy of Sciences. All rights reserved.