Nonlinear analysis of tunnel slab under hydrogen explosion

Hydrogen explosions consequent to hydrogen-fuelled vehicle (HFV) accidents in a tunnel could cause great losses of lives and property due to its special characteristics, such as high pressure blast waves. Reliable predictions on the structural response of a tunnel impacted by blast waves are crucial to develop effective mitigation technologies to protect the integrity of the structure. This case study conducts a numerical analysis of a tunnel ventilation slab subjected to an explosion. wave calculated by a CFD study on this specific scenario. The focus here is the mechanical structural response of a reinforced concrete (RC) slab caused by the pressure time history of the explosion wave in the case tunnel. Two different finite element codes (ANSYS Mechanical APDL and DIANA) are applied comparing the respective results. The effects of the reinforcement diameter, reinforcement position, concrete strength and boundary condition are studied and discussed. Numerical results show that the RC slab suffers significant damage under larger explosive impulses. The influences of reinforcement position and concrete strength on the RC slab deflection are very slight. However, reinforcement diameter and boundary condition play an essential role in the RC slab dynamic response. Improving reinforcement diameter and reducing the freedom of the RC slab can effectively enhance the properties of the RC ventilation slab under hydrogen explosion loads.