The inclination of the interslice resultant force in the limit equilibrium slope stability analysis

Abstract

Currently, all of the semi-precise slice methods are developed based on the assumed relationships between interslice shear and normal forces (or interslice force directions). These assumed relationships lack theoretical basis, and reduce the accuracy of determination of the thrust force of sliding mass in the reinforced structure design. Therefore, a precise relationship of interslice forces is required. A functional relationship between the interslice force direction and influencing factors including the gradient of the sliding surface, the gradient of the slope surface and the shear strength of the sliding surface is deduced based on the Mohr-Coulomb failure criterion. Then, the deduced equation is employed to determine the interslice force directions and assess the stability of the Houzishi landslide, which is a case in the Three Gorges Reservoir area in China. The comparison among the inclinations of the interslice resultant force obtained by the numerical simulation, our derived equation and assumed values of other slice methods shows that our derived equation provides the best match with the simulation results. In addition, the safety factor of our method that incorporates the newly derived equation, is consistent with the precise slice method, further demonstrating the effectiveness of the equation. Therefore, the semi-precise slice method that incorporates the derived relationships of interslice forces provides a more reliable approach for estimating the thrust force in the design of reinforced constructions.