First World Congress of International Consortium on Geo-disaster Reduction (1st ICGdR World Congress)

Landslide-generated tsunamis represent a significant disaster chain in reservoir areas, where wave propagation and run-up along river channels can pose severe threats to communities, infrastructure, and other exposed assets located on opposing or adjacent slopes. Although previous studies have extensively investigated wave generation and propagation, the disaster-causing mechanisms of landslide-tsunamis acting on buildings on the opposite bank remain insufficiently understood, particularly under varying bank morphologies and building configurations.

This study, set in the Three Gorges Reservoir area, systematically investigates the impact process of landslide-induced tsunamis on nearshore buildings through an integrated experimental and numerical approach. A series of physical model experiments was conducted, with 315 test cases designed by varying water depth, bank slope, bank geometry, building height, and building distance from the shoreline. The effects of landslide scale and water depth on tsunami run-up and dynamic pressure were examined, alongside the influence of bank slope and geometry on run-up behavior and pressure response.

The results reveal that the dynamic actions of landslide tsunamis on the bank predominantly manifest in two forms: tongue-shaped jet impact and wave pulse impact, with the former characterized by a limited spatial extent, short duration, and high pressure. Steeper bank slopes reduce the jet impact range, while variations in bank geometry alter the jet trajectory. When tsunamis impinge on buildings, overtopping restriction leads to concentrated pressure on the wave-facing side, and dynamic pressure decays markedly with increasing distance from the shoreline. Both run-up height and impact pressure exhibit strong spatial attenuation, indicating a pronounced locality in the hazard effect.

Based on the physical impact process, a quantitative vulnerability assessment framework was established using dynamic pressure as the key indicator, encompassing four failure modes: impact, overturning, crushing, and uplift. The findings contribute to a better understanding of the physical mechanisms underlying landslide-tsunamis induced building damage, and provide a scientific basis for quantitative risk assessment, anti-tsunami design, and coastal town planning in reservoir areas.

Disaster chain,Landslide-induced tsunamis,Run-ups,Dynamic pressure,Building vulnerability