Modeling Near-Field Impulsive Waves Generated by Deformable Landslide Using the HBP Model Based on the SPH Method

Landslide-generated impulsive waves (LGWs) in reservoir areas can seriously threaten waterway safety as well as human life and properties around the two side slopes. The risk reduction and mitigation of such a hazard require the accurate prediction of near-field wave characteristics, such as wave amplitude and run-up. However, near-field LGW involves complicated fluid-solid interactions. Furthermore, the wave characteristics are closely related to various aspects, including the geometry and physical features of the slide, river, and body of water. However, the empirical or analytical methods used for rough estimation cannot derive accurate results, especially for deformable landslides, due to their significant geometry changes during the sliding process. In this study, the near-field waves generated by deformable landslides were simulated by smoothed particle hydrodynamics (SPH) based on multiphase flow. The deformable landslides were generalized as a kind of viscous flow by adopting the Herschel-Bulkley-Papanastasiou (HBP)-based nonNewtonian rheology model. The HBP model is capable of producing deformable landslide dynamics even though the high-speed sliding process is involved. In this study, an idealized experiment case originating from Lituya LGW and a practical case of Gongjiafang LGW were reproduced for verification and demonstration. The simulation results of both cases show satisfactory consistency with the experiment/investigation data in terms of landslide movement and near-field impulsive wave characteristics, thus indicating the applicability and accuracy of the proposed method. Finally, the effects of the HBP model's rheological parameters on the landslide dynamics and near-field wave characteristics are discussed, providing a parameter calibration method along with suggestions for further applications.