Numerical simulation study on the effects of the fragmentation degree of high-position landslides on impulse wave characteristics

Landslide-generated impulse waves are a typical type of secondary geological hazard whose formation is closely related to the structural characteristics of the sliding mass. To investigate the influence of the fragmentation degree on wave response mechanisms, this study focuses on high-position landslides and selects a representative real-world engineering case as the prototype. A three-dimensional numerical model is developed based on Computational Fluid Dynamics to simulate the sliding and wave generation processes under varying degrees of fragmentation. By systematically comparing the sliding behavior, water entry disturbances, wave propagation characteristics, and dam face responses, the results indicate that higher fragmentation leads to earlier disintegration during sliding, significantly weaker water entry disturbances, reduced wave heights, delayed main waves, and attenuated propagation capacity. In contrast, intact sliding masses exhibit stronger inertial concentration effects, resulting in more efficient wave generation, greater amplitudes, and steeper waveforms. The study further reveals that structural variations of the landslide mass affect not only near-field wave patterns but also the extent and persistence of far-field energy diffusion. These findings deepen the understanding of how landslide structure influences wave dynamics and provide theoretical and numerical references for disaster prevention and mitigation in high dam and reservoir areas.