3-D simulation of tunnel structures under blast loading

In this paper we want to study the behaviour of an underground structure subject to blast action. Other than the normal operating loads we considered the actions generated by a thermal gradient simulating the action of a fire load and by a pressure wave simulating an explosion. Initially the theoretical aspects of the problem were exanimated, and then a model was developed in numerical form and implemented through a finite element analysis. This modelling allows the simulation of a real scenario, e.g., railway tunnels with reinforced concrete structure that is subject to a fire generation and a subsequent explosion. The simulation involved aspects of thermal analysis, and therefore the structural problem was tackled analysing the tensions in the structure generated by the effect of temperature-pressure generated by the fire and by the overpressure generated by the blast. Only following this approach the most important factors influencing the dynamic response and damage of structure can be identified and the appropriate preventive measures can be designated.