Numerical and Physical-Model Investigation of Landslide-Generated Surge Waves from a Localized Unstable Zone in the Yangqu Canyon Reservoir: Wave Generation and Propagation

Abstract

Surge waves generated by rapid landslide entry into canyon reservoirs can threaten near-dam hydraulic structures. This study examines a representative post-failure hydrodynamic scenario for the localized unstable Zone B of the No. 1 deformation body slope near Yangqu Hydropower Station. A three-dimensional numerical model was constructed from DEM terrain data and validated using a 1:200 physical model under reservoir water levels of 2710 m and 2715 m. The simulation represents the landslide mass as a prescribed moving rigid body and focuses on wave generation, propagation, and dam-front response after landslide initiation. For the Zone B case at 2715 m with a volume of 1.0 × 106 m3 and an entry velocity of 15 m/s, the first wave reached the opposite bank at about 10 s, the prescribed landslide front reached the riverbed region at about 20 s, and distinct secondary and reflected waves developed at about 50 s. The first-wave height at the downstream monitoring point was about 3.15 m, and the maximum wave height was approximately 3.58 m. Comparison with the 1:200 physical model shows that the numerical results reproduce the first-wave arrival time, main peak height, and main secondary-wave phase reasonably well for the prescribed Zone B scenario. The simulated dam-front response is spatially non-uniform, indicating that the results are most suitable for preliminary screening of hydrodynamic risk under specified local landslide scenarios.