Anti-plane seismic performance of a shallow-buried tunnel with imperfect interface in anisotropic half-space

Abstract The current research presents a semi-analytical solution for the anti-plane dynamic response of a shallow-buried lined tunnel. The tunnel with an imperfect interface between the tunnel lining and its surrounding medium is embedded in an anisotropic and elastic half-space medium. For anti-plane problems, three elastic constants can describe the characteristics of medium anisotropy according to the generalized Hooke’s Law. Therefore, the complex variable function method and multi-polar coordinate system were applied to express the wave fields with three unknown constants in this study. These constants also automatically satisfy the zero-stress boundary condition on the horizontal ground surface in the half-space and the Sommerfeld radiation condition at infinity. The imperfect interface is represented by a series of elastic spring model. Meanwhile, parametric sensitivity analyses indicate that both the medium anisotropy and the imperfect interface stiffness affect significantly the dynamic response of the medium-lining system including stress and ground surface displacement. Besides, the influence of both factors is also dependent on incidence direction and frequency.