Numerical Analysis of the Blockage Effect of the Tunnel Drainage System on the E-Han Expressway

The discharge of groundwater and the load on lining structure are both significantly impacted by obstruction tunnel drainage system. In this study, fluid–structure interaction model was established based finite difference software FLAC3D. Then, research explored effects symmetric asymmetric blockage in circular drainpipe, transverse drainpipe at pipe joint pore water pressure, displacement stress surrounding rock. Our revealed following points: (1) When a symmetrical or asymmetrical occurred only blocked part would be affected, but pressure back side crown wall between two adjacent drainpipes increase 200%, 22% 41%. (2) increased maximum 146%, 4% displaced 8% to extent. (3) Both drain led failures connected with joint. This sections had an impact rock nearby.