Blast resistance performance of shield tunnels under internal explosions: Field tests and numerical simulation

Recent accidental explosions have underscored the urgent need to evaluate the blast resistance of underground structures, particularly shield tunnels. This study investigates the dynamic response and damage evolution of shield tunnels subjected to internal explosive loading to provide critical insights for blast-resistant design and reinforcement. A combined approach of field explosion tests and numerical simulations was used to analyze the effects of explosive equivalent (TNT equivalent) and initiation position (central vs eccentric). The results show that increasing the explosive equivalent significantly amplifies the dynamic response of the tunnel. Eccentric initiation leads to localized strain exceeding the material’s critical threshold on the near-blast side, resulting in perforation and localized damage. In contrast, central initiation causes relatively lower overall damage, with the arch bottom and lower arch shoulder remaining vulnerable areas. This study clarifies the critical influence of explosive load and initiation position on the blast resistance of shield tunnels, providing valuable experimental data and theoretical support for anti-explosion design.