Pressure wave propagation in tunnels

The most significant accidental explosions in recent decades have been those which generated a pressure wave that propagated outwards, causing considerable damage to the environment, as demonstrated by the explosion at the port of Beirut in August 2020.

The propagation of an airborne pressure wave in an open environment has been the subject of a great deal of work, in the context of urban development control. This phenomenon is relatively well known today, and "simple" methods for assessing its effects exist, depending on the type of explosion involved. On the other hand, the problem of pressure wave propagation in confined environments (buildings made up of a succession of rooms, corridors, etc.) has received relatively little attention. However, it does arise in a number of accident situations. This is particularly the case in the defense sector, where explosive charges may be stored in underground installations consisting of storage chambers and various galleries.

More generally, this issue concerns all industrial sectors where an explosion phenomenon (gas, solid explosives, etc.) can take place in a confined environment with multiple rooms and/or corridors, or in open-air explosion situations which can lead to penetration of the pressure wave generated – via certain openings (weak doors, ventilation ducts, etc.) – in a building which is otherwise generally resistant and must guarantee a level of internal safety (in the nuclear and defense sectors).

To ensure the safety of people present in these confined spaces, and to limit the consequences of an accident through domino effects (by guaranteeing the resistance of safety-critical equipment, for example), it is essential to be able to quantify the propagation of the pressure wave by determining the level of overpressure it induces. This article takes stock of the main existing approaches to pressure wave propagation, particularly in confined environments.