Energy and structural evolution process of high-altitude and long-runout landslides induced by a strong earthquake

Abstract. It is often difficult to restore the evolution process and energy transfer of ancient landslides that have occurred over a long time. In this paper, the contour restoration method is used to restore the topography before the Mogangling landslide according to the contour of the surrounding mountains. In order to better analyze the landslide movement process and analyze the energy change, the numerical simulation method is used to reproduce the Mogangling landslide. In the process of numerical simulation, the displacement and velocity of the whole and part of the landslide mass are monitored, respectively, so as to extract their potential energy, kinetic energy, and dissipation energy. At the same time, the effective collision of blocks in the process of landslide is obtained by extracting the local peak value of the displacement velocity curve. Meanwhile, the Alpha shape algorithm was employed to extract the volume and surface area of the landslide body from 3D point cloud data, thereby enabling the calculation of its volume expansion rate and area growth rate to quantify the morphological evolution characteristics during the landslide movement process. The results show that for the whole landslide, its energy change conforms to the law of conservation of energy; For some blocks, the energy is not conserved due to the collision and compression of surrounding rock mass; Compared with the upper rock mass, the lower rock mass is compressed more frequently, receives more energy transfer, and has a longer migration distance.