Slope Stability Analysis Considering Rainfall Infiltration Based on Energy Conservation

In recent years, increasing slope instability accidents caused by rainfall occur. In order to quantitatively analyze the influence of rainfall infiltration on slope stability more accurately, based on the traditional Green–Ampt infiltration model, the influence of the slope’s angle and the characteristics of unsaturated loess were considered and the saturated zone and unsaturated zone were calculated separately in this paper. Through the energy conservation equation, this paper transferred the influence of rainfall infiltration into generalized penetration force and changed the penetration force and composite soil nailing wall supporting force into vertical article point method using the Bishop internal force hypothesis. The slope was divided into two parts, which were calculated, respectively, and integrated by the weighted solving method, and the calculation formula of overall stability of composite soil nailing wall retaining structure was deduced under the action of rainfall. For example, the difference of 1.165 obtained in this paper’s formula is 0.122 compared with the traditional Bishop method (1.043), which not only verifies the correctness of the formula in this paper but also reflects the weakening of the stability coefficient caused by rainfall. Since the soil parameters of unsaturated soil are weakened by rainfall, there may be some errors, and the result provides reference for similar support under special natural environment.