Parametric investigation on the sealant behavior of tunnel segmental joints under water pressurization

Abstract

Water leakage through segmental joints is a clutch issue for shield tunnels during both the construction and operation stages. However, very limited knowledge has been obtained in this area. To address this deficit, this paper investigates the sealant behavior of gasketed joints in shield tunnels using a high-fidelity finite element (FE) model. In the developed FE models, the material nonlinearity of the rubber-fabricated sealing gaskets is simulated by the Mooney-Rivlin hyperelastic constitutive model; the complex contact behaviors (e.g., amongst gaskets and segments and gaskets themselves) are properly captured. The model is capable of realistically reproducing detailed water-leakage behavior and computing the water-leakage pressure through application of the built-in fluid pressure penetration (FPP) module in ABAQUS. The FE model is validated against available experimental data of gasket-in-groove mechanical tests and joint waterproof tests. It is demonstrated that the modelling approach developed in the paper can replicate adequately the load-deformation response and reasonably predict water-leakage pressures. The validated FE model is then used to undertake a comprehensive set of parametric studies that elucidate the influence of nine key design parameters on the sealant performance of gasketed joints. It is found that controlling joint opening and/or rotation has a fundamental effect on ensuring satisfactory waterproof behavior, even if a relatively large joint offset exists. The sealant capacity of the joint is positively related to the hardness of the gasket, while it is not highly sensitive to the geometry of the groove and properties of contact behavior. The findings contribute to an improved understanding of sealant behavior of gasketed joints under water pressurization and permit the potential development of codified design frameworks.