Vector-Sum Method for 2D Slope Stability Analysis Considering Vector Characteristics of Force

The vector-sum method (VSM) is advanced by considering the vector characteristics. As a cost of this advantage, a predefined global sliding direction is required, which has been a key issue for the application of the VSM. Although the VSM has been steadily refined since its initial version in 2008, limited progress on this issue has been achieved, and the global sliding direction is still prespecified by assumption. In the aim of solving this issue, this article proposes a rigorous analytical solution based on the principle of potential energy minimization. In addition, the VSM is improved by comparing the resisting moment with the driving moment at the moment center, which can be determined by the shape of the slip surface. Finally, this method is verified to be feasible by three classical earthen slopes with different soil composition. Compared with the solutions found by the rigorous Morgenstern-Price method with the half-sine function as the interslice force function, the calculated results demonstrate that the proposed method can accurately estimate slope stability.