Analytical solution for stresses around shallow tunnels in transversely isotropic ground subjected to surcharge loadings

Rock masses often exhibit anisotropy. In this study, the surrounding-rock response induced by tunnel excavation in a transversely isotropic rock mass is studied analytically. The initial stresses caused by gravity, surcharge loads, support pressure, and the anisotropic directions are fully considered in the theoretical derivation. The mechanical model of shallow buried tunnel is divided into two simply connected domains, that is, one model with a hole in the infinite plane and the other model without a hole in the half plane. The analytical solution of the surrounding rock stress of tunnel excavation in transversely isotropic rock mass is derived by using the complex variable theory and the Schwartz alternating method. The analytical model can accurately and quickly predict the ground response. The degenerate solution is consistent with the results of other reference. In addition, the analytical solution is in good agreement with the finite element numerical simulation results. Finally, parameter analysis is carried out to study the effects of surcharge location, anisotropy angle and tunnel depth on surrounding rock stress. The analytical solution presented in this paper is of great significance for anisotropic rock mechanics and the verification of related numerical simulations. In addition, it provides a new idea for the preliminary design of shallow buried tunnels in transversely isotropic rock mass in the future.