Damage assessment of ring nets in flexible barriers subjected to consecutive rockfall impacts

In response to the unpredictable nature of rockfall hazards, flexible barrier systems must endure both single and consecutive impacts in practical scenarios. This study conducted a preliminary series of large-scale impact tests, focusing on the damage assessment of ring nets in flexible rockfall barriers, while considering various rock shapes, sizes, and net specifications. Performance indicators, including impact force, net deflection, and energy dissipation, derived from consecutive impact tests were systematically compared with those obtained from single impact tests. The experimental findings reveal a strong correlation between damage evolution in ring nets during consecutive rockfall impacts and both impact force and energy dissipation. Despite the significant deflection observed in the flexible barrier, existing damage indices incorporating the deflection indicator proved unsuitable for evaluating damage under multiple impacts. Consequently, we propose a new damage assessment index that combines force ratio and energy ratio. This index proves highly effective in distinguishing performance degradation from failure of the ring nets as the damage accumulates. Additionally, this index has the potential to assess damage evolution and failure characteristics in practical flexible barrier systems.