Effects of near-fault seismic loadings on run-out of large-scale landslide: A case study

• The largest landslide induced by the Wenchuan earthquake was studied.
• Effect of near-fault seismic loadings on landslide run-out was studied by DDA.
• Baseline corrected real ground motion records with co-seismic displacement were used.
• Size effect of the huge landslide was considered.

This study presents the run-out analysis of the Daguangbao landslides subjected to near-fault multi-direction earthquake forces using discontinuous deformation analysis (DDA). The Daguangbao landslide is the largest landslide induced by the 2008 Wenchuan earthquake. In order to investigate the effects of near-fault seismic force on landslide run-out, kinematic behavior of sliding mass is simulated by a dynamic discrete numerical analysis method called DDA. In this simulation, based on the shape of failure surface and the feature of slope geology, the whole slope is divided into three parts: base block, upper sliding mass, and lower sliding mass. Then two sliding masses are divided into the smaller discrete deformable blocks based on pre-existing discontinuities. Size effect of the huge landslide is also considered. Baseline corrected real horizontal and vertical ground motions are taken as volume force acting to the base block. The results show that seismic force has a significant influence on the landslide progression, sliding distance, and shape of post-failure. Results of the horizontal-and-vertical situation are in good agreement with those obtained from post-earthquake field investigation, remote sensing image and description from the survivors.