Effect of imperfect interfaces on dynamic response of a composite lining tunnel with an isolation layer under plane P and SV waves

Abstract An analytical solution to the scattering of plane P and SV waves by a composite lining tunnel with imperfect interfaces in full space is presented using the wavefunction expansion method. The spring model is introduced to depict the imperfect interfaces among the surrounding rock, primary support, isolation layer and final lining of the tunnel. The influences of incident wave types, interface spring coefficient, and shear modulus and thickness of the isolation layer on the dynamic stress concentration factor (DSCF) of tunnel are systematically discussed. It is concluded that the DSCF generated by SV waves in the final lining of composite tunnel is larger than that of P waves. The interface imperfection tends to weaken the DSCF in final lining but intensify that in primary support. The effect of isolation layer is dependent on its shear modulus and thickness as well as the types and frequency of the incident waves.