Hydro-mechanical interaction analysis of reinforced concrete lining in pressure tunnels

Concrete-lined pressure tunnels under high internal water pressures require to be reinforced to withstand failure. Since these tunnels exert the sources of water flow to the rock formations, a suitable arrangement of lining reinforcement is required to minimize water losses from the tunnel. A simulation of this hydro-mechanical interaction can be implemented based on a direct-coupled method using the ABAQUS finite element program. In addition, a subroutine code has been developed to evaluate the influence of internal water pressure on the permeability coefficient variation of porous media. In the present study, the reinforcement distribution in the lining is investigated to limit water losses from the tunnel. To verify the proposed model, the numerical and analytical solutions are compared based on the elastic behavior of the media and a reasonable agreement is obtained. The results of the structural nonlinear analysis indicate that water losses from the tunnel remain at a lower amount with small diameters and spacing in the concrete lining for at the same percentage of reinforcement.