Method of Stress Field and Stability Analysis of Bedding Rock Slope Considering Excavation Unloading: Fid-Bau Portal

Method of Stress Field and Stability Analysis of Bedding Rock Slope Considering Excavation Unloading

Qin, Hui / Yin, Xiaotao / Tang, Hua / Cheng, Xu / Yuan, Hao

The stress state of a slope and its analytical solution are prerequisites for stability analysis. Currently, the limit equilibrium method cannot consider the stress state of slopes, and the solution of bedding slope stress remains in numerical simulations for a long time. In this paper, based on the theory of the elastic stress solution of the wedge top under a concentrated load, the analytical solution of the stress field was obtained using Matlab programming. Unloading stress analysis method (USAM) for determining the sliding surface of the bedding rock slope, safety factor (F_s), and reinforcement forces (F_r) were proposed. The USAM is compared with the Limit Equilibrium Method (LEM) and Finite Element Method (FEM) in terms of the F_s, F_r, sliding surface position, and sliding surface stress. The results show: 1) The analytical stress of the slope can be obtained quickly and conveniently using the USAM, while subsequent programming helps in faster completion of the stability evaluation of the bedding rock slope. F_s, F_r, sliding surface position, and sliding surface stress are all close to the results obtained by the FEM. 2) The USAM is more suitable for analyzing slopes when the angle between the slope surface and structural plane is greater than 20° (θ > 20°) and the slope angle is greater than 45° (β > 45°). 3) Through the analysis of specific engineering cases, the safety factor calculated by USAM are 0.06 and 0.02 larger than those obtained by LEM and FEM, respectively, and the required reinforcement force for the slope is closer to that obtained by FEM. The novel stress and stability analysis method allows for the rapid evaluation and optimal engineering design of bedding rock slope.