Determination of the Main Direction of a Sliding Body Based on a Three-Dimensional Finite-Element Limit-Equilibrium Method

The safety evaluation of three-dimensional rock or soil slopes strongly depends on the factor of safety based on the potential direction of sliding body. In fact, considering the objectivity of sliding, there should be a fixed main sliding direction for a potential landslide mass. However, in the past, there was no reasonable explanation for defining the main direction of sliding and it used to be considered as a variable to be optimized. In this paper, a refined finite-element limit-equilibrium method is proposed in couple with a fixed main direction of sliding to evaluate the safety of the three-dimensional slope. In this approach, the potential main direction of sliding can be directly determined as the projection direction of the resultant sliding force of the landslide on the horizontal plane once the stress field of sliding body was achieved. Theoretical derivations and several classical examples are performed for verification. The factor of safety of a sliding body in relation with the main direction of sliding are calculated and the results are comparable and consistent with the theoretical solutions. It is proven that the proposed slope stability analysis method based on the main direction of sliding could provide an alternative and convenient tool for engineering on design and reinforcement for rock or soil slope.