Effect of internal explosion on tunnel secondary and adjacent structures: A review

Abstract

Safety of tunnel structures subjected to accidental or hostile explosions inside road and utility tunnels has attracted increasing attentions. It is essential to understand the dynamic behaviours of main and secondary structures of tunnels subjected to explosions occurring inside the tunnels (i.e., internal explosions) and the dynamic response of adjacent structures against stress waves induced by the explosions for reliable blast-resistant designs and effective protections of tunnels and structures in the proximity. In the authors' previous paper, dynamic responses of main tunnel structures subjected to both internal and external explosions have been reviewed. Therefore, this paper focuses on the review of the relevant studies and discussions on the effect of internal explosions on secondary structures of tunnels (i.e., partition walls inside tunnel) and adjacent engineering structures (e.g., adjacent tunnels and buildings above the tunnel). Firstly, the paper presents common forms of secondary tunnel structures and adjacent engineering structures. Secondly, possible internal explosion scenarios during the construction and operation of tunnels are given. Furthermore, studies of the effect of direct explosion loads on secondary structures and the subsequently induced stress waves imposed on adjacent structures are reviewed. The current research status and the need for further studies for effective protections of tunnels and adjacent structures against internal explosion loads are reviewed and discussed in this paper.