Three-dimensional numerical modelling on localised leakage in segmental lining of shield tunnels

A new numerical approach for modelling the localised leakage of shield tunnel lining is proposed, in which the localised leakage is simulated using a one-dimensional leakage element. The proposed method overcomes the limitations on the solid meshing of the leakage element and also reduces computational error due to the size difference between the solid leakage element and lining element. The simulated results show that groundwater leakage causes a decrease in the pore pressure in the surrounding ground, which is difficult to capture with existing modelling methods. Localized leakage at the joints leads to tunnel deformation in the shape of an inclined oval in the transverse direction. The leak location in the transverse direction has a significant impact on the tunnel deformation in the longitudinal direction. Leakage at the roof has less impact on tunnel settlement, but its impact on the ground surface settlement should not be overlooked.