Response induced by transient blasting or seismic P-wave around a diversion tunnel with an imperfect rock-liner interface

The work focuses on transient response of a deep-buried circular lined diversion tunnel with an imperfect rock-liner interface, which is full of water, subjected to an aperiodic blasting or seismic P-wave in a full space. Laplace transform was first applied to governing equations in rock mass, liner and water to obtain the frequency-domain expressions of wave fields in various media under planar blasting or seismic P-wave. Furthermore, a spring interface model was adopted to describe rock mass-liner imperfect characteristics. Laplace transformation was performed for the imperfect rock-liner and perfect liner-fluid boundary conditions to determine complex coefficients of wave fields in the frequency domain. Ultimately, corresponding time-domain solutions triggered by the planar blasting or seismic P-wave were evaluated by numerical inverse algorithm. Limitation analyses including a deep-buried empty cavity and lined counterpart verified the proposed method under triangular P-wave. The theoretical results indicated that the scopes perpendicular to perturbation direction generated pronounced dynamic tensile or compressive stress concentration under the blasting or seismic P-wave. The rock-liner contact state had a significant influence on the transient response of surrounding rock, liner and water and the effect of radial elastic coefficient on dynamic response was more sensitive than that of hoop counterpart, especially in fluid. The existence of fluid promoted the interaction between stress wave and tunnel, resulting in more remarkable fluctuations of time-domain response. These results can provide a theoretical basis for the earthquake resistant design of diversion tunnel and support.