Discrete element modeling of debris avalanche impact on retaining walls

In China, gravity retaining walls are widely used as protection structures against rockfalls, debris flows and debris avalanches along the roads in mountainous areas. In this paper, the Discrete Element Method (DEM) has been used to investigate the impact of granular avalanches and debris flows on retaining walls. The debris is modeled as two dimensional circular disks that interact through frictional sliding contacts. The basic equations that control the deformation and motion of the particles are introduced. A series of numerical experiments were conducted on an idealized debris slide impacting a retaining wall. The parametric study has been performed to examine the influences of slope geometry, travel distance of the sliding mass, wall position, and surface friction on the impact force exerted on the wall. Results show that: 1) the force achieves its maximum value when slope angle is equal to 60°, as it varies from 30° to 75°; 2) an approximate linear relationship between the impact force and the storage area length is determined.