Active countermeasures against landslide impulse wave hazards: Energy dissipation mechanism of the new weir- pool type wave-resistant structure

Breakwaters or seawalls designed to mitigate landslide-induced impulse wave are rare but serve as the last barrier protecting reservoir shore settlements from impulse wave attacks. Further research on low-height breakwater and seawall designs compatible with human habitats is crucial. This study proposes a novel weir-pool type wave-resistant structure based on the energy dissipation principles observed in natural cascading water flows within stepped pools. Through a series of two-dimensional flume experiments , the energy dissipation mechanisms and wave resistance effects of both single and multi-level weir-pool structures were investigated. The experimental results demonstrate that the Weir-pool type wave-resistant structure exhibits significantly enhanced wave dissipation performance compared to conventional vertical seawalls. Within the tested wave height range, the improvement in energy dissipation efficiency reached 14.99 %–76.81 %. The impact location of the impulse wave plays a decisive role in the wave dissipation efficiency of the weir-pool type wave-resistant structure. When the impulse wave strikes before the junction point between the pool base and the rear wall, overtopping is effectively prevented; beyond this point, the efficiency ranges between 65 % and 90 %. Through systematic analysis of the structural characteristics and hydrodynamic response, incident wave height, pool depth, and pool width were identified as the key design parameters. By integrating these findings with hydraulic jump theory, a design methodology for single-stage Weir-pool type wave-resistant structures was developed. The research findings provide valuable references for landslide-induced impulse wave prevention and control in reservoir areas, as well as practical engineering design guidelines, thereby significantly enhancing the safety of reservoir shoreline communities. • Novel weir-pool type wave-resistant structure inspired by stepped pools' natural flow energy dissipation proposed. • Study reveals impulse wave impact location critically determines wave resistance efficiency in weir-pool type wave-resistant structure. • Single-level weir-pool type wave-resistant structure design method based on hydraulic jump theory proposed and experimentally validated.