Model tests on dynamic responses of surrounding rock and support structure on underground tunnel under combined dynamic and static loading

The effect of blasting vibration on the macroscopic failure characteristics of underground tunnels has been investigated, but little attention has been paid to the stress and deformation characteristics of underground tunnels under the combined action of explosion waves and in-situ stresses. Consequently, enhancing the bearing capacity of surrounding rock masses by adopting effective reinforcement measures is an urgent problem that needs to be solved. Due to high in situ stresses at great depths, it is difficult to conduct field tests on various reinforcement methods. In this study, using the deep underground tunnels as a prototype, large-scale physical model tests were adopted to examine the stress and deformation characteristics of the unlined tunnels, the rock bolt reinforced tunnels, and the lined tunnels under the coupling action of in-situ stress and blasting waves induced by different charge quantities, with the purpose of providing the necessary theoretical and technical support for the design and support of deep protective engineering.