Hydraulic fracturing-based analytical method for determining seepage characteristics at tunnel-gasketed joints

Waterproof performance of gaskets between segments is the focus of shield tunnels. This paper proposed an analytical method for determining seepage characteristics at tunnel-gasketed joints based on the hydraulic fracturing theories. First, the mathematical model was established, and the seepage governing equation and boundary conditions were obtained. Second, three dimensionless parameters were introduced for simplifying the expressions, and the seepage governing equations were normalized. Third, analytical expressions were derived for the interface opening and liquid pressure. Moreover, the influencing factors of seepage process at the gasketed interface were analyzed. Parametric analyses revealed that, in the normalized criterion of liquid viscosity, the liquid tip coordinate was influenced by the degree of negative pressure in the liquid lag region, which was related to the initial contact stress. The coordinate of the liquid tip affected the liquid pressure distribution and the interface opening, which were analyzed under different liquid tip coordinate conditions. Finally, under two limit states, comparative analysis showed that the results of the variation trend of the proposed method agree well with those of previous research with the minimum error of 0.43%. Overall, the proposed analytical method provides a novel solution for the design of the waterproof in shield tunnels.