Numerical Simulation of the Large-Scale Huangtian (China) Landslide-Generated Impulse Waves by a GPU-Accelerated Three-Dimensional Soil‒Water Coupled SPH Model

This work presents an improved soil‒water coupling model to simulate landslide-generated impulse waves (LGIWs) in a unified smoothed particle hydrodynamics (SPH) framework, where both water flow and landslide motions are modeled by SPH using an interface coupling technique. Graphics processing unit technology based on an open-source platform DualSPHysics is chosen to employ the landslide dynamics and soil‒water interface coupling to achieve the capability of large-scale simulation and high-resolution modeling for three-dimensional LGIW problems. A subaerial landslide-generated water waves, is simulated to demonstrate the accuracy and ability of this model. The Huangtian LGIW is then simulated to reproduce the entire disaster chain, including landslide dynamics, fluid‒solid interaction, and surge wave generation. Particle resolution dependence is examined, giving a particle distance of 5.0 m, which can provide a converged landslide deposit and surge wave. The simulation shows that in the Huangtian LGIW, the landslide deposit volume was approximately 41.6 million m³ (600 m width, 768 m length, and 400 m above the still water level), with an immersed landslide volume of 11.3 million m³; for the surge wave, the maximum wave and run-up heights were 34.3 and 48 m, respectively. These results are within the estimated ranges of both the landslide and surge wave according to limited field survey data. The case study of the Huangtian LGIW provides a typical reference of how to reproduce a reliable whole process of large scale multi-physical and multiscale LGIW, including full information of landslide dynamics, interface coupling behavior, and surge wave characteristics.