Rockfall impact resistance performance of composite structure with corrugated plate and reinforced concrete

Objective The rockfall hazard threatened a certain cut-and-cover tunnel structure on Lanzhou-Xining railway in complex mountainous terrains. This study proposed a reinforcement solution by using composite structure with corrugated plate and reinforced concrete. The solution aimed to improve the deficiency of impact resistance performance of traditional reinforced concrete structure. Method It combined the flexible deformation of corrugated steel plates with the rigid load-bearing capacity of concrete, constructing an optimized protective system. A refined 3D finite element model was developed by using LS-DYNA to precisely simulate the material nonlinearity, contact behavior, and energy transfer during rockfall impact. The model validity was confirmed through comparative analysis and empirical formulas. Result With equivalent impact energy, the composite structure demonstrated significant advantages over conventional reinforced concrete. The maximum effective stress decreased by approximately 30%, reducing instantaneous structural loading. The rock penetration depth reduced by 50%-80%, enhancing surface anti-penetration performance. The internal damage volume droped by 79.73%, reflecting improved material integrity. With the increase of impact energy, the stability of impact resistance performance of composite structure was further highlighted. The growth rate of penetration depth slowed by 14.77%. The increase of reinforcement bar stress was 42% lower. The failure mode shifted from through-thickness cracking to localized non-penetrating damage. It effectively suppressed the concrete cracking expansion and steel plastic deformation, preventing structural failure. Conclusion The proposed composite structure fully optimized impact resistance performance through the mechanism of efficient stress dispersion and energy dissipation. It would offer a promising technical approach for rockfall prevention in mountainous railway tunnels and for retrofitting existing infrastructure.