Performance of Tunnel Lining Materials under Internal Blast Loading

Performance of different tunnel lining materials under internal blast loading is compared in the present study through three-dimensional nonlinear finite element analyses. A tunnel in sandy soil has been considered for the analyses. The performance of single layered steel plate, plain concrete (PC) slab, steel fibre reinforced concrete (SFRC) slab, sandwich steel-dytherm foam-steel (SDS) panel and steel-polyurethane foam-steel (SPS) panel linings under blast loading has been examined. For material modelling, Drucker-Prager plasticity for soil, Johnson-Cook plasticity for steel, concrete damaged plasticity based on the concepts of fracture-energy-based damage and stiffness degradation in continuum damage mechanics for concrete, SFRC and crushable-foam plasticity for foams have been used. Strain rate dependent material parameters have been used for all lining materials and soil. Internal blast loading of 10 kg TNT has been simulated using the pressure-time curve obtained through CFD-calculations. The resulting displacements at soil-lining interface have been evaluated. It is observed that SDS and SPS sandwich panel linings cause much less displacement in the soil under blast loading as compared to the PC and SFRC linings.