Simulating Collapse of the Farmland Stone Walls due to Backfill Soil Saturation Using the 3D-DEM-MPS Method

Because many farmland stone walls have recently collapsed due to frequent heavy rains, the need to clarify the mechanism of the collapse has become a pressing issue. However, most prior analytical studies on the stability of farmland stone walls focused on seismic damage, and studies that examined the damage caused by heavy rain are scarce. The present study simulated the collapse behavior of farmland stone walls due to the effect of pore water pressure by using the 3D-DEM-MPS method, while considering the solid–fluid interaction. In order to evaluate the effect of the pore water in the backfill behind the stone wall, a comparison between two cases was made: with and without pore water. In the latter case, the displacement of the backfill was small and the wall was stable. Contrastingly, in the former case, sliding failure easily occurred in the backfill even with only slight movement of the wall; this eventually caused the wall to collapse by the combined effect of the slip created between stone blocks and the increasing force imposed by the sliding backfill. This study successfully demonstrated that it is possible to reproduce the collapse behavior of farmland stone walls, caused by backfill soil saturation following heavy rain, using the 3D-DEM-MPS method.