Numerical investigation of landslide-induced waves: a case study of Wangjiashan landslide in Baihetan Reservoir, China

Landslide-induced waves often result in severe casualties, economic losses, and even catastrophic consequences, which are far more destructive than the landslide itself. In this paper, accurate geomorphological and geological characteristics of the Wangjiashan landslide in Baihetan Reservoir, southwest China, were obtained through field investigations, and a three-dimensional model was built for numerical calculation. Through the time series curve of cumulative deformation, the water level variation of the reservoir was found to be the major factor causing the landslide deformation and eventual failure. The generation and propagation progress of water waves induced by the Wangjiashan landslide was simulated by coupling the granular flow model and renormalization group turbulence model in FLOW3D. The results show that a large sliding mass silts up the channel, forming a landslide dam with a maximum height of 21.5 m. Nevertheless, it does not block the channel and will not affect standard navigation on account of the wide channel in this area. The maximum run-up wave height of waves spreading to the Xiangbiling resettlement area on the opposite bank is 3.7 m. As the resettlement area is only 1.3 km away from the landslide, and its elevation is only 2.5 m higher than the normal water level of the reservoir, landslide-induced waves should be considered a potential threat. The most vulnerable area affected by landslide-induced waves is about 8 km long along the river, where wave run-up heights are more than 1 m. The results in this paper have important reference values for the early warning and prevention of potential disasters caused by landslides and landslide-induced waves.