Abstract：To reveal the evolution process and influencing factors of shield tunnel segments joint leakage, the shield tunnel joint leakage calculation formula was derived based on fracture seepage model, then the longitudinal stress relaxation along the shield tunnel was further considered, and a time-varying formula was established eventually for circular joint leakage calculation. The leakage evolution law and the related parameters sensitivity were discussed combining with Qianjiang tunnel example. The results show that the leakage of shield tunnel circular joint increases with the widening of the opening between rings or the raising of the external water-head, whereas the leakage decreases with the increasing of the joints stiffness. The circular joint leakage is influenced sensitively by the opening between lining rings. The leakage becomes obvious worse when the longitudinal stress relaxation along tunnel is considered together. The leakage will increase by 12 times as much as before when the longitudinal stress attenuating from 3.2MPa to 1.2MPa, and the amount of leakage water between different points is expanded significantly. The leakage flow at the bottom of tunnel is about twice as much as that at the top. The leakage phenomenon will significantly decrease if the longitudinal connection bolts are re-tightened after the shield tunnel occurs longitudinal stress relaxation. The re-tightening of connection bolts will lead to a reduction of the leakage of circular joints to 80% of the original amount immediately, and to a reduction of the leakage of circular joints to less than 20% of the original amount finally. The influence of longitudinal stress relaxation of shield tunnel on waterproof performance of lining rings should be emphasized in practices.
