Abstract. The huge Donghekou landslide was triggered by the Wenchuan earthquake in 2008 with about 2.4×107m3 of rock displaced. The landslide is considered as an example of earthquake-induced ejection event, but the kinematic processes are not well understood. We used the 2-D granular discrete element method to characterize the kinematic behavior and mechanics of this ejection landslide. The initial boundary conditions were applied along the ball-wall contacts by using derived velocities integrated from strong motion data with a duration of 125 s, including the peak acceleration near the Donghekou area. The constraints were primarily determined from the final geometry of the landslide and geological structures to account for the actual landslide characteristics. Simulated results showed that the large local seismic acceleration and a free face under the sliding body, caused by the dip difference between the upper slide face and the natural slope, originated from the ejection of the landslide. For the lower slide body, its kinematic mechanism was changed during sliding. Initially it was a pushed landslide, and then gradually changed to a retrogressive landslide. The eroded bed on the slope during the landslide could slightly increase the runout distance from 1435 m to 1519 m, and was predicted in the numerical simulation.
Analysis of landslide damage caused by the 2008 Wenchuan earthquake using strong motion data: A case study in the Beichuan county town
