Research on the dynamic response of shallow-buried circular non-complete bonded tunnels under anti-plane line source loading

The scattering of seismic waves by shallow-buried underground structures has significant theoretical value in the engineering field. However, previous studies have mainly focused on the case of plane waves or the case of complete bonding between lining and surrounding rock, with little consideration of the effects of source distance and non-complete bonding between lining and surrounding rock. In order to deepen the understanding of the influence of source distance and non-complete bonding on seismic wave scattering, the series solution of the dynamic response of shallow-buried circular non-complete bonded tunnels under the loading of anti-plane line source was derived based on the displacement discontinuity model, wave function expansion method, Graf formula and mirror method. The accuracy of the obtained solution was verified by the relationship between the residuals of the inner and outer boundary conditions of the lining and the number of truncated terms in the series solution. By systematically analyzing the parameters of this series solution, the influence of factors such as the contact stiffness between lining and surrounding rock, lining modulus, lining thickness, tunnel depth and source distance on the displacement and circumferential shear stress on the inner surface of the lining was discussed. The results show that the contact stiffness between lining and surrounding rock has a significant influence on the dynamic response of the tunnel, especially in cases with relatively low contact stiffness, where the amplitude of the dynamic response of the tunnel can be very large. Increasing the lining modulus reduces the displacement but increases the circumferential shear stress. Increasing the lining thickness can simultaneously reduce the displacement and circumferential shear stress. As the tunnel depth increases, the maximum displacement and circumferential shear stress on the inner surface of the lining shifts towards the apex of the tunnel. Increasing the horizontal distance between the line source and the tunnel increases the relative amplitude of the tunnel's back wave side.