Blast Response and Failure Analysis of a Segmented Buried Tunnel

Abstract

Underground tunnels are vulnerable to terrorist attacks that can cause collapse or severe damages to the tunnel structures, thereby requiring extensive repairs. This paper presents the blast impact on a reinforced concrete segmental tunnel buried in soil, with reference to a number of parametric conditions: soil properties, soil cover, distance of explosive from the tunnel centreline and explosive weight, and analyses of the possible failure patterns. A fully coupled fluid structure interaction technique incorporating the Arbitrary Lagrangian-Eulerian (ALE) method was used in this study. Results indicate that a tunnel in saturated soil is more vulnerable to severe damage than that buried in either partially saturated soil or dry soil. The tunnel is also more vulnerable to surface explosions that occur directly above the centre of the tunnel than those that occur at any equivalent distance in the ground away from the tunnel centre. The research findings provide useful information on modelling, analysis, overall tunnel response and failure patterns of segmented tunnels subjected to blast loads. This information will guide future development and application of research in this field.