Numerical simulation of potential impulse waves generated by the Mogu rock landslide at varying water levels in the Lianghekou Reservoir, China

Abstract

Reservoir impoundment and water level fluctuations often trigger landslides and their secondary disasters, such as potential impulse waves, posing a serious threat to the safety of people along the reservoir and dam areas, causing economic losses and even catastrophic consequences. This study delves into a comprehensive field investigation and monitoring of the engineering geological conditions and deformation mechanisms the Mogu rock landslide. Impoundment is identified as the primary factor inducing slope deformation, with the cumulative displacement of the sliding body showing no signs of convergence, indicating potential instability. By coupling the elasto-visco-plasticity model and the RNG turbulence model in FLOW3D, an actual surge disaster near the Lianghekou Reservoir dam area is replicated to validate the reliability of the numerical method. Building upon this, a three-dimensional model is established to calculate potential impulse waves generated by the Mogu rock landslide, and the risk to the dam is evaluated. Under varying water level conditions, the simulated heights of impulse waves do not surpass the dam elevation, demonstrating a satisfactory safety margin. Given the inherent danger of landslide-induced wave disasters, continuous attention is warranted, and preventive measures and suggestions are proposed to address these concerns. Additionally, the study explores the contributions of water level fluctuations to the primary wave height, the maximum run-up on the opposite bank and the dam, and the attenuation rate of wave height along the river channel. The results provide significant reference values for the early warning and prevention of comparable reservoir landslides and potential landslide-induced waves worldwide.