Numerical Modeling of Shallow Buried Tunnel Subject to Surface Blast Loading

Abstract

Dynamic response of shallow buried tunnel with three different cross sections subjected to surface blast loading using LS-DYNA version R10.1.0 is investigated. Multimaterial arbitrary Lagrangian Eulerian (MM-ALE) is employed for this study. Strain softening of concrete is incorporated in terms of tensile cracking. Whereas, strain rate dependent behavior of reinforcement is defined using visco-plastic formulation. The main objective is to investigate the nonlinear behavior of reinforced concrete that constitutes the tunnel lining under a surface blast. Extensive parametric analysis has been performed to determine the effects of change in explosive charge weight, lining thickness, and cover depth on the behavior of tunnel under blast loading. Further, a comparative study based on the degree of blast resistance has been carried out considering three tunnel cross sections, namely, horseshoe, box, and circular. Finally, the blast damage assessment of tunnel with varying geometry, explosive charge weight, and cover depth has been investigated to arrive at the most vulnerable blast scenario.