Abstract:Subsea tunnel will influence the hydraulic regime of the surrounding ground and tends to induce seepage towards the excavation boundary. Tunnel linings are almost never completely impermeable and it is also not practical to build an impervious tunnel. Generally,tunnels are thus designed to operate under a drained condition. A great deal of uncertainties,however,remain concerning leakage controls in subsea tunnels. Therefore,in many cases,owners,designers and contractors are interested in evaluating the benefits of considering partially or fully drained tunnel linings. The design procedures of a subsea tunnel have to address any detrimental effects associated with groundwater movement. Unfortunately,the complicated hydraulic boundary conditions and the long period required to measure the behaviors are the main difficulties in identifying the hydraulic interaction that is paramount in case of subsea tunnels. In subsea tunnels,the main hydraulic factors to be controlled are the amount of leakage and water pressures on the linings. Thus,the paper attempts to investigate the hydraulic lining-ground interaction using a coupled numerical approach. Adopting specially devised elements that can consider the permeability of drainage systems will represent the deterioration of drainage system. The long-term hydraulic lining-ground interaction including the relationship between the amount of leakage and the water pressure on the lining is studied. Design considering the control of leakage and the evaluation of water pressure for the subsea tunnels is also presented.