Study on the instability process and surge waves of the near-dam bank collapse body in the Lianghekou Hydropower Station

Abstract

The recent deformation of the Tuodaxi dumping deformation body on the near-dam bank of Lianghekou Hydropower Station is significant and continues to increase. In order to assess the threat posed by its destabilisation damage to the life safety, properties and infrastructures of the reservoir and the residents along the dam area, systematical analysis was carried out on the destabilisation movement process of the landslide and the landslide surge phenomenon by using the coupled Finite Element-Smooth Particle Hydrodynamics(FEM-SPH) method with the Tuodaxi dump deformer on the near-dam bank of the Lianghekou Hydropower Station as a research object. Numerical simulation result show that the instability process of the Tuodaxi collapse body lasts approximately 30 seconds, with a maximum movement speed of 25 m/s and a maximum displacement of 1 827 m. The landslide-induced initial surge wave reaches a maximum height of 28.9 m, and the maximum wave height at the dam site is 0.61 m. The study demonstrates that the FEM-SPH coupling method accurately captures the complex dynamic behavior of landslides and surge waves. The landslide instability process can be divided into three stages: initiation, high-speed sliding, and impact-deposition. Based on the study result, the dam risk assessment indicates that, under normal water levels, the maximum wave height propagating to the dam does not exceed the dam′s elevation, ensuring a high safety margin. The findings of this study provide valuable references for early warning and prevention of similar reservoir landslides and potential landslide-induced surge waves.

Keywords

Lianghekou Hydropower Station / Tuodaxi collapse body / FEM-SPH method / instability process / landslide-induced surge wave