The Effect of Explosion in a Tunnel Tube on its Damage

Abstract

The aim of the work is to study the impact of an explosion in a tube on its damage. The theory of Landau-Liftschitz gas dynamics and the damage criterion by the Hoek-Brown in the structure are applied. If the charge is placed centrically in the tube, it is fairly easy to predict both the locations and damage levels. Therefore, the paper is oriented to the case where the charge is placed eccentrically. Air movement is described by the solution of non-linear Euler’s equations by final volume element method, while the response of the fiber reinforced concrete structure of the tube to impact waves is described by the time dependent 20-nodes flat shell elements. In order to ensure the geometric compatibility along the interface between the two media (structure, air), gas dynamics in the air is described by block elements, while the shell is approximated by the finite element. In this way, the problem solved is divided into a description of the air velocity and pressure and the velocity and stress in the solid phase, separately; interaction of the effects caused by the explosion initiated inside of the tube and its impact on the solid phase is concentrated along the interface between these two media. The calculation focuses on the early stages of interaction development when most likely damage is assumed.