Sensitivity Analysis of Sandy Slope Stability under Rainfall Infiltration

Abstract

Abstract：In this paper, the rainfall characteristics influence on the stability of sandy slope is studied by combining the theoretical analysis and model tests. Firstly, the model test is carried out and the finite element software （Geo-Studio） is used to simulate the seepage process of the slope under different rainfall conditions. The change curves of the pore water pressures in the different positions of the slope are obtained by the model test and numerical simulation. The applicability of the numerical model is verified by comparing the fitting of the pore water pressures curves. Three factors about slope ratio, rainfall intensity and permeability coefficient of sand are discussed through the numerical simulation, and the stability coefficients of slope is obtained by numerical calculation used as the comparison object. The results show that: in rainfall process, through the observation of the model test and numerical simulation of rainfall infiltration process, slope toe was the first to reach saturation where the slope failure starts from. The major factors that affect the stability of the slope from big to small in turn are the slope ratio, the permeability coefficient and rainfall intensity. When the rain intensity increases from 30mm/h to 150mm/h, the stability coefficients of the slope were reduced from 1.323 to 1.095 when it rained for 36 minutes. The curves showed that stability coefficients decrease with the increase of rain intensity, which is approximately linear. The results of this study can provide the references for the failure mechanism of the slope due to rainfall and the slope protection design.