Numerical investigation of the Baige landslide-induced wave propagation in a narrow river channel

Landslide-induced waves pose significant risks to human life, property, and infrastructure, especially in relatively narrow channels where wave propagation differs from that in reservoirs or coastal areas. This study introduces a drift-flux model, treating the two-phase mixture as a whole to simulate flow-like landslide-induced waves efficiently. The model combines the renormalization group k‑ε turbulence model and volume of fluid method to accurately describe wave formation and propagation. After verification through mesh size convergence tests and a benchmark experiment, the model is applied to the Baige landslide-induced waves in a narrow river channel on October 10, 2018. The results indicate that wave evolution occurs in four stages: run-up, inundation, run-down, and propagation along the valley. The run-up heights and wave decays vary between upstream and downstream locations at the same distance from the landslide center, depending on the extension direction of the river channel. The numerical predicted maximum run-up height of the Baige landslide-induced waves on the opposite hill slope is 112 m, consistent with the actual situation. However, the maximum run-up heights predicted by empirical equations are lower than both the actual and numerical simulated values due to the lack of consideration of multiple wave reflections in a narrow river channel. Utilizing the previous empirical equations to evaluate landslide-induced waves in a narrow river channel may result in underestimating their hazard. This study contributes to the risk assessment of landslide-induced waves in narrow water bodies, and its findings are essential for safety management and siting decisions regarding infrastructure and facilities.