Pipe–soil interaction under the rainfall-induced instability of slope based on soil strength reduction method

Abstract

As the characteristics of looseness, heterogeneity, and natural variability of soil, landslide–pipe interaction is a complicated process. PRCI guidelines consider soil as springs to analyze landslide–pipe interaction when soil is at the ultimate state. In this paper, the strength-reduction method was used to analyze the landslide–pipe interaction at the limit equilibrium state of the soil. The fluid–solid coupling model was introduced to analyze the influence of rainfall on slope stability. The soil–pipe interaction under the effect of slope instability induced by rainfall was simulated and the influence of different pipe diameter-to-thickness ratio, internal pressure, location of the potential failure surface (PFS), and buried depth on the mechanical response of pipe were investigated. It is found that the buried depth will influence the pipe–soil interaction mechanism. With the increase of buried depth, D/t of pipe, the maximum stress of pipe will be greater. While the increase of internal pressure can provide a uniform force to resist pipe deformation, the maximum pipe stress will be smaller. Besides, the slope PFS was divided into three parts to investigate pipe–soil interaction, the results showed that buried pipe at the slope toe has larger maximum stress. The safety factor of the slope was validated against Bishop and Janbu method.