Effects of grain composition on the stability, breach process, and breach parameters of landslide dams

The sudden breach of a landslide dam seriously threatens the safety people and property downstream. failure mechanism dams is significantly affected by grain size distribution material. In this study, series experiments are conducted to investigate effects composition on stability, process, parameters dams. results show that remain stable with seepage for coarse-dominated dam, fail overtopping along piping fines-dominated alone balanced-composition dam. mode regulated material, stress condition hydraulic gradient. Backward erosion occurs fines contents <5 % due movement debris, during which width:depth ratio cross section first decreases then increases. By contrast, higher than 15 %, headcutting step-pool structure develops because small grains more easily washed away coarse grains. scenario, increases decreases. Dam longevity nonlinearly increasing content. hydrography changes from single peak multiple peaks content, discharge sensitive median diameter addition, degree, defined as releasing potential energy (total minus residual energy) total lake upstream controlled diameter. This study improves our understanding mechanisms aids hazard assessment