Stress field and stability calculation method for unloading slope considering the influence of terrain

The initial terrain of a slope has a significant impact on the stability and stress state during excavation. In this study, the theory of elastic stress solutions under concentrated loads at the top of a wedge-shaped body was employed to develop a method for calculating the slope stress field and stability, considering terrain effects during excavation. The rationality of this method was validated by comparing the changes in the safety factor, stress of the sliding surface, and position of the sliding surface using the limit equilibrium method (LEM) and finite element method (FEM). The research findings indicated the following: (1) A sliding surface search method was proposed, leading to the development of a slope unloading stress analysis method (USAM) considering the influence of terrain. This method allows for the rapid and straightforward determination of the stress field and safety factor of the excavated slope simultaneously. (2) When the USAM was applied to analyze slopes with small heights, the safety factor tended to be slightly larger. This phenomenon can be attributed to the assumption made in the elastic stress solution theory for wedge tops subjected to concentrated loads. However, this assumption does not significantly affect the stability analysis of high slopes. (3) The calculated sliding surface stresses and potential sliding surface positions were close to those derived using the strength reduction method. This study introduces a new perspective for slope stability analyses and stress field solutions that consider terrain effects.