Sealing performance of a precast tunnel gasketed joint under high hydrostatic pressures: Site investigation and detailed numerical modeling

摘要

Aiming at the sealant behavior at the engineering scale, this paper first presents a site investigation on the joint responses to reveal the characteristics of probability distribution and the correlations between joint deformations and leakage. A detailed numerical model verified with experimental data, is established to interpret the multidimensional variation law of gasket sealing performance subjected to different joint deformation states. The results show that: the sealing performance of a rubber gasket decreases significantly with increasing joint opening, and fluctuates with increasing joint offset. Based on this finding, a new quantitative method for evaluating gasket sealing performance is developed. The sealing performance is divided into "joint opening dominant area" and "joint offset dominant area" according to the degree of influence in terms of joint opening, while the deformation area is further evaluated as "insufficient sealing area (labelled in red) ", "critical sealing area (labelled in yellow)" and "sufficient gasket sealing area (labelled in green)" according to the influence of joint offset. The results of this study can be beneficial to an improved understanding of the leakage behavior of gasketed joints in high-water pressure shield tunnels.