Seepage flow around tunnels in swelling rock

Abstract The swelling phenomenon in tunneling is numerically modelled as a coupled hydraulic‐mechanical process. The present communication focuses on the significance of the constitutive seepage flow equations, as well as on the importance of the hydraulic boundary conditions. The observed absence of swelling deformations at the tunnel walls and the crown can be explained as a consequence of varying hydraulic boundary conditions along the excavation boundary. According to the presented numerical results, the non‐linearity of the unsaturated flow equations has a decisive qualitative influence on the predicted deformation field.