Due to the progressive development of military destructive weapons such as conventional
weapons, a consequence development of the fortified structures is essential. One of the most
important types of the fortified structures is tunnel in rock media.
The basic premise of this work is studying the response of tunnels in rock-media exposed
to high explosion loads, which help tunnel designers and military engineers in estimating
displacements, stresses and over all damage in the tunnels due to wave propagation generated
by that explosion loads. In this study, the tunnel steel lining for a vertical sidewall crosssection
tunnel is studied for different rock types. 2500 kg TNT was used as an explosive load.
This charge was located at 3.25m-bellow ground surface. The distance between charge and
tunnel crown was fixed to 10m for all models.
With regard to finite element solution, an appropriate mesh is employed to represent the
geometry of the problem. The rock and lining are simulated by solid elements (one quarter of
the domain) in a three-dimensional finite formulation.
Joint to joint are used to simulate rock-lining interaction. The steel lining thickness to arc
radius (ts/R) ratio was considered 1/300, 1/150, 1/100, 1/75 and 1/30 for ts1, ts2, ts3, ts4, ts5, and
ts6 respectively. Von-Mises material model is used to simulate the behavior of steel lining.
Grade 50 of steel is used where yield stress is 360MPa and the strength is 468.4MPa, modulus
of elasticity equal to 210000MPa, elongation equal to 12%.
The response of displacements and stresses, for all rock types and tunnel spans are
determined at different lining points.