In this study, a circular cross-section tunnel with concrete lining is analyzed by the finite
element code AUTODYN 3-D version 4.3., which is probably the most extensive code dealing
with explosive loads in the world.
First, a model calibration was performed for the AUTODYN finite element parameters and
material models by using a field test problem with available field measurements. Then, based
on the calibration results, a parametric study has been performed by means of finite element
non-linear dynamic analysis to investigate the effect of underground explosion on the
behaviour of circular tunnel with concrete lining in rock media. A charge of 2500 kg TNT was
used as an explosive load. This charge was located at 3.25m-bellow ground surface with two
crown-detonation distances 10 and 15m for all models.
Finally, a non-linear rational analysis is conducted for the parametric study results to develop
simple equations to determine peak displacements and strains for circular tunnels with
concrete lining. These equations may help tunnel designers and military engineers in
estimating displacements, and strains, then overall damage in the tunnels with no need to
deal with complex finite element non-linear dynamic codes.