Effect of an Imperfect Interface on Seismic Response of a Composite Lining Tunnel Subjected to SH-Waves

The nonlinear behaviors of rock-lining and the lining-lining interfaces significantly influence the seismic response of tunnels with composite linings. Therefore, a closed-form analytical solution was developed for the dynamic response of tunnels with composite linings subjected to SH (horizontally polarized shear)-waves, and the two interfaces were modeled by the Coulomb-slip model. A case study was then conducted to investigate the effects of the two interfaces on the seismic response of tunnels. The results show that the imperfections of the two interfaces lead to decreases in the stresses of the composite linings and an increase in the deformation of the final lining. However, the two interfaces play opposite roles in influencing the deformation of the initial lining. As the shear stiffness of the shotcrete-cast concrete interface increases, the peak stresses in the composite linings increase rapidly at first and then tend to be stable. The effect of the shear strength of the interface, however, depends on the stress distribution in the interface. The mechanical parameters of the interfaces should be carefully determined for the seismic design of tunnels with composite linings. (C) 2018 American Society of Civil Engineers.