Investigation of the run-up characteristics of landslide-generated impulse waves on the dam under the influence of the bend

Landslide-generated impulse waves (LGIWs) occurring in mountain reservoirs exhibit obvious topography-related characteristics during long-term evolution. This paper conducts a comprehensive study on the run-up characteristics of impulse waves on the dam built downstream of the river bend. Large-scale physical similarity model experiments are carried out based on the potential LGIWs hazards in the Rumei (RM) reservoir to investigate the run-up process of impulse waves on the dam. Numerical simulations are then conducted using a hybrid discrete element method–smoothed particle hydrodynamics and shallow water equations model to further analyze the LGIWs disaster and the run-up evolution of impulse waves. The reasons for the complex run-up characteristics are analyzed, the influence of bends under different dam surface inclinations, and the dam position is also discussed. The results show that under the influence of the bend, the run-up process exhibits distinct temporal and spatial effects. Three wave motion patterns gradually appear at the dam surface due to the influence of the bend in front of the dam: reflected waves between the flanks, incident waves from the river, and water rebound under gravity. The maximum run-up height occurs when various factors are superimposed simultaneously, which may cause even a small incident wave to generate a large run-up height. As the inclination of the dam surface decreases, the influence of the bend on the run-up process gradually diminishes. Under the effect of the bend, the disaster of LGIWs may be amplified. This study recommends that the whole lifecycle of the LGIWs should be studied based on high-resolution terrain to get a more accurate assessment of the LGIWs disaster.