Vulnerability analysis of tunnel linings under blast loading

In the present study, a comparative assessment on the performance of conventional and advanced tunnel lining materials subjected to blast loading is done using a three-dimensional non-linear finite element analysis procedure. The conventional tunnel lining materials analyzed herein are plain concrete, steel, reinforced cement concrete, and steel fiber–reinforced concrete. The advanced tunnel lining materials analyzed herein are dytherm, polyurethane, and aluminum syntactic foam sandwich panels with steel–foam–steel composites. The pressure generated by 10？kg Trinitrotoluene (TNT) is applied to each element on the inner wall of the tunnel which has an effect equal to the scaled distance Z？=？1.16？m/kg1/3. Analyses are conducted by varying the thickness of lining materials for a tunnel built in rock domain. The response of the tunnel lining materials, for example, deformation, stresses, and strains generated at different interfaces, is compared with each other to assess the best suitable material for the present blast scenario discussed herein. It is observed from the simulations that the reinforced cement concrete and steel–aluminum syntactic foam (90？μm)–steel are found to be the suitable tunnel lining materials for the present blasting scenario described herein. Moreover, a set of probabilistic analysis is also performed for the suitable tunnel lining materials decided through deterministic analyses using Monte Carlo simulations. The results obtained are normal random distribution curves depicting the extent of deformation in lining materials. A probability failure curve is also proposed for the suitable lining materials