Seismic response of tunnel lining structure in a thick expansive soil stratum

Abstract

The seismic response of a tunnel lining structure is essential for its safety design and construction. The objective of this study is to investigate the seismic response of a tunnel lining structure embedded in a thick expansive soil stratum. First, the deformation and internal force characteristics of tunnel lining structure under seismic action are evaluated from a theoretical perspective. Second, a finite element (FE) analysis is carried out of the seismic responses of the tunnel lining structure and ground stratum. In the FE analysis, the bolted connections in the tunnel lining structure are simulated using the local stiffness reduction method (LSRM). The LSRM reduces the stiffness of the lining segments affected directly by the bolted connections using a stiffness reduction coefficient (SRC), while leaves the stiffness of the rest of the lining segments to remain to be unchanged. The results indicate that under the effect of transversal waves propagating in the direction perpendicular to tunnel axis, the transversal displacement characteristics of the tunnel lining structure are almost identical to that of the surrounding soil stratum. They both decrease with an increase in buried depth. The circumferential distributions of shear force, bending moment, and axial force in lining segments are varied, but the magnitudes of them increase with an increase in SRC.