The seepage field around twin noncircular tunnels in anisotropic sloping

A new and efficient theoretical model for studying the seepage field around two noncircular tunnels in sloping ground is proposed through analytical derivation. The model considers the exact interaction between two tunnels with arbitrary shapes and locations, as well as the permeability anisotropy, whose principal orientation is along any direction. By applying the Schwartz alternating method and conformal mapping, the analytical solutions of the hydraulic head and pore pressure can be obtained. These solutions strictly satisfy all governing equations and conditions. The correctness and accuracy of the analytical solutions are verified by the good agreement between the theoretical and numerical results. The proposed theoretical model can be applied to the cases with any tunnel shape, slope angle, anisotropic direction and degree. The quantitative influences of the anisotropy ratio, slope angle and tunnel shape on the seepage field are obtained, and some useful charts are provided. The proposed model can efficiently and quickly predict the seepage flow around tunnels in anisotropic sloping ground.