Three-dimensional coupled hydromechanical analysis of localized joint leakage in segmental tunnel linings

Abstract

Water leakage has become the main defect that affects the safe operation of shield tunnels in the saturated stratum. Long-term leakage is proven to change the load distribution and stress state of the tunnel lining, which hampers the structural performance of the tunnel. This paper proposes a novel numerical approach to simulate the localized leakage of segmental linings. The mechanical response of the longitudinal/circumferential joints is obtained by using a developed joint connection element, while the seepage response of the joints is simulated by implementing the DFLOW subroutine in Abaqus. The hydraulic boundary conditions are set at both longitudinal joints between segments and circumferential joints between rings. The hydromechanical behavior of the surrounding soil is incorporated based on the stress-pore water pressure interaction. A series of parametric numerical analyses is performed to explore the influences of partial leakage at the circumferential joints on the lining forces, lining deformation, and ground settlement. The simulation results demonstrate that the internal forces and maximum settlement of the tunnel structure and the magnitude of the ground settlement are substantially affected by the seepage rate, while the shear stiffness of the circumferential joints has only a slight effect. The longitudinal settlement of the tunnel and ground surface increase with the increase in the seepage rate of the circumferential joints, and a leakage-location-related distribution pattern is observed. The shear stiffness of circumferential joints mainly affects the pattern of the differential settlement of segmental linings in the longitudinal direction. These analyses indicate the appropriateness of such detailed three-dimensional simulations for capturing the realistic hydraulic and mechanical interactions of joint-leaked segmental linings.