Transient responses of deep-buried unlined tunnels subjected to blasting P wave

Abstract

Dynamic perturbation inevitably induces rock mass damage in deep engineering, especially for high-level in situ stress. The study presented in this paper focuses on the theoretical and numerical responses of deep twin circular tunnels subjected to transient disturbance. Based on wave function expansion method, Graf’s addition theorem, integral transform and its inversion, dynamic responses along the tunnel peripheries are analyzed theoretically. Moreover, with resort to a self-developed code, CASRock, the elasto-plastic responses triggered by coupled static geo-stress and blasting disturbance are investigated numerically. The analytical results indicate that the positions of maximum circumferential stress concentration are approximately perpendicular to the disturbance direction; the most remarkable radial vibrations occur at the incident sidewall and the peak hoop velocities are near the incident side. The numerical results demonstrate that the in situ stress field and characteristics of disturbance load affect the final failure region and damage mechanism around the tunnels. The theoretical and numerical results can provide guideline for the support and design of deep-buried tunnels.