Visco-elastic interface and dynamic response of a lined tunnel in anisotropic rock mass under unloading waves

Anisotropy of rock masses plays a significant role in predicting the dynamics response of tunnel excavation in rock mass. In this paper, the dynamic response of a lined tunnel in anisotropic rock mass under unloading waves is studied, and the dynamic visco-elastic interface model is introduced to analyze the interface effect. By using the wave function expansion method, the unloading waves and the wave fields in the tunnel lining are expressed, and the viscosity and elastic coefficients of interface model are proposed to analyze the imperfect interface effect on the dynamic response of existing tunnel. Three unloading paths due to the tunnel excavation are considered, and the analytical solutions of displacements and stress fields around the existing tunnel lining under these unloading paths are derived. An approximate numerical integration method is introduced to calculate the displacements and stresses around the existing tunnel. In numerical examples, the dynamic circumferential stress around the existing tunnel under different interface parameters, unloading paths and geometrical and physical parameters of tunnels is analyzed. Comparison with the existing numerical results validates this dynamic model. • The dynamic model of a lined tunnel in anisotropic rock masses under unloading waves is constructed. • The dynamic visco-elastic interface model is introduced to analyze the interface effect. • The interacting effect between the anisotropic property of rock mass and the visco-elastic interface is analyzed. • The effect of interface on the dynamic response of existing tunnel under three unloading paths is discussed.