A probabilistic limit equilibrium framework combining empirical load transfer factor and anisotropy of soil cohesion is developed to conduct pile-reinforced slope reliability analysis. The anisotropy of soil cohesion is determined conditioned on that the thrust force direction is parallel to the major principal direction and it is easily combined with load transfer factor, which are related with soil parameters, and pile parameters. The proposed method is illustrated against a homogeneous soil slope. The sensitivity studies of pile parameters on factor of safety (FS; calculated at respective means of soil parameters) and beta demonstrated that the anisotropy of soil cohesion tends to pose significant effect on reliability index beta than on FS. The effect of anisotropy of soil cohesion on FS is found to be slightly different under different pile locations, whereas its effect on beta is observed to be least if piles are drilled at the middle part of slope and more significant effect is observed when piles are drilled at the lower and upper part of slope. The plots from the sensitivity studies provide an alternative tool for pile designs aiming at the target reliability index beta. The proposed method contributes to the pile-reinforced slope stability within limit equilibrium framework. The effect of anisotropy of soil cohesion on the pile-reinforced slope stability is explored and found to be more significant from the aspect of reliability index than from that of factor of safety. image

The construction of the 'Dayangyun' Expressway has generated a large number of engineering landslide disaster chains, mainly due to the lack of consideration of the influence of soil sediment anisotropy and slope geometric characteristics on slope stability, instability risk, and failure characteristics. It is urgent to propose a reasonable geometric optimization design method for slopes to prevent the occurrence of such disasters. This study established a random field model that incorporates rotational anisotropy-related structures of strength parameters. Subsequently, the slope reliability index(beta) was computed to evaluate slope stability. Additionally, failure modes were classified, introducing the shallow failure probability (PL) to assess failure risk. Finally, a comprehensive probability analysis framework with two indexes(the beta and PL) was designed to determine the optimal platform width of the slope(Lopt), and two slope cases were utilized for research and application purposes. The results indicate that rotation angles(theta) and platform width (L) significantly impact slope stability and instability risk. As the theta increases, the beta and PL exhibit S and M shaped trends, respectively. Specifically, the beta and PL display a logarithmic and exponential increasing trend with the increase of the L, respectively, this trend determines the Lopt. The dual-index comprehensive probability analysis framework can be employed to assess slope excavation stability and risk, as well as optimize slope geometry design. The research results can be used to prevent the occurrence of excavation slope disasters.