The high-speed and long run-out landslide is characterized by high kinetic energy and long moving distance, which leads to enormous loss to human beings. However, there are rare investigations on the disaster reduction effects of retaining-wall structure on high-speed and long run-out landslide rock avalanche. Numerical simulation provides an important method to study the effects. In this paper, the numerical manifold method was used to simulate the movement process of high-speed and long run-out landslide rock avalanche induced by strong earthquake in Niuquangou, China. The accumulation state and movement characteristics of the landslide were studied through a series of numerical tests. The effects of vegetation coverage, retaining-wall on it accumulation state of rock avalanche were studied, and the disaster reduction effects of retaining-wall was evaluated. Compared with the discrete element method, the numerical manifold method can simulate the contact and collision of any shape blocks, avoiding the impact of rolling friction of round particles on the simulation results during motion. The simulation results showed that the effects of increasing vegetation coverage on the landslide movement path is limited. In order to intercept rock avalanche better, retaining-wall needs to be arranged on the motion path to effectively reduce moving distance and long-distance accumulation of rock avalanche. When the retaining-wall is placed in different positions,it has defferent effect on the landslide rock avalanche,and the optimal position of the retaining-wall is determined. In addition, compared with effects of increasing the height of the retaining-wall, the multiple rows of retaining-wall structure can more effectively intercept the rock avalanche and reduce it harm to downstream.
