Stability analysis of the Zhangmu multi-layer landslide using the vector sum method in Tibet, China

The Zhangmu landslide is located on the China–Nepal border in Tibet, China, which has recently become a serious threat to the lives and properties of local people. In order to efficiently quantify the stability of the Zhangmu landslide, a new method named the vector sum method (VSM) is proposed. Differing from conventional slope-stability analysis methods, the VSM considers both the magnitude, the direction of force and the strength-reserving definition of the safety factor based on the actual stress field of slope achieved from finite element analysis. Moreover, the global sliding direction of potential landslides was theoretically deduced by the principle of minimum potential energy, while the safety factor can be directly computed by not only the force limit equilibrium of the whole sliding body in the global sliding direction but also the moment limit equilibrium at the moment center. Finally, stability analysis of the Zhangmu landslide was performed by the proposed method, and verified against the rigorous Morgenstern–Price method.