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

Abstract

Reservoir impoundment and water level fluctuation often trigger slope instability and its secondary disasters, such as potential impulse waves, posing a serious threat to the safety of people along the reservoir and the dam area, causing economic losses and even catastrophic consequences. This study delves into a thorough field investigation and monitoring of engineering geological conditions and deformation mechanisms the Mogu toppling rock slope. Impoundment is the primary factor inducing slope deformation, and the cumulative displacement of sliding body has not converged, signifying potential instability. Coupling the elasto-visco-plasticity model and the RNG turbulence model in FLOW3D, an actual surge disaster near Lianghekou Reservoir dam area is reenacted to validate reliability of the numerical method. On this basis, a three-dimensional model is established to calculate potential impulse waves generated by Mogu toppling rock slope, and the risk of 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 contributions of water level fluctuations to the head wave height, the run-up wave height on the opposite bank and the dam, and the attenuation rate of wave height along the river channel are explored. The results in this study present significant reference values for the early warning and prevention of comparable reservoir landslides and potential landslide-induced waves worldwide.