Cascading amplification mechanisms in a dam-break flood disaster chain triggered by landslide-generated waves

Complex hydrological extremes and natural disasters can cause landslide-generated waves in dam reservoirs; such waves may result in earth-rock dam failure, resulting in severe cascading flood disasters. In this study, we carried out an integrated laboratory model experiment to analyse the processes of disaster chain; furthermore, we conducted a refined numerical simulation based on computational fluid dynamics. Through systematic numerical experiments, we analysed cascading amplification mechanisms in a dam-break flood disaster chain triggered by landslide-generated waves, with respect to the overtopping failure flood characteristics under intense surge impacts. The results indicated that when compared with the failure process of earth-rock dams in response to natural flood events, the response to landslide-generated waves was more intense, with more pronounced disaster characteristics. We noted an unfavorable shift in the peak flood discharge and time of peak, the impulse wave as a critical catalyst that accelerates the failure process and magnifies the downstream hazard. In this study, we proposed a scale-adaptive empirical formula for disaster-amplification coefficients and quantified the relationships between amplification factors and dimensionless parameters. This study can serve as a theoretical foundation for risk assessment in reservoir areas and offers critical insights for policymakers to develop effective emergency-planning and disaster-mitigation strategies.