The response of rock tunnel when subjected to blast loading: Finite element analysis

In the past few decade tunnels were targeted to explosives and that resulted in sizeable structural damage. The increase in the strategic importance of tunnel construction has increased the demand for the blast‐resistant design approach. The present paper considered an internal blast loading on a rock tunnel constructed in Quartzite rock. A three‐dimensional finite element model of the tunnel has been developed in Abaqus. The diameter of the tunnel has been kept constant to a two‐lane transportation tunnel. However, the thickness of the concrete liner, depth of overburden, and mass of explosive charge has been varied to understand the response in different possible conditions. The Jones‐Wilkins‐Lee, Concrete Damage Plasticity, and Mohr‐Coulomb material models have been used for the modeling of trinitrotoluene, concrete, and rock respectively. Blast has been formulated through Coupled‐Eulerian‐Lagrangian technique. The tunnel at 12.5 of the depth of overburden has been found 2.7‐times more blast resistant than 5 m. Moreover, the extent of damage in shallow depth tunnels found to be more than the tunnels at higher depth of overburden. A three‐dimensional finite element analysis of underground rock tunnel has been performed. Effect of overburden pressure and liner thickness has been observed. Blast analysis has been done developing Coupled‐Eulerian‐Lagrangian modeling method.