考虑盾构隧道纵向应力松弛的环缝渗漏水计算分析

为揭示盾构隧道环缝渗漏水演变过程及其影响因素，基于裂缝渗流模型推导盾构隧道管片环缝渗流量计算公式，进一步考虑隧道纵向应力松弛的影响，建立环缝渗漏水演变的时变状态模型，结合算例进行环缝渗漏水演变规律探讨和参数敏感性分析。结果表明，盾构隧道渗漏水量随着环间张开量增大或者外部水头高度的提高而增大，随着环间接头刚度的增大而减小。张开量对环间渗漏水的影响较为敏感，隧道顶部的渗流量始终小于底部。盾构隧道纵向应力越低，隧道渗漏水现象越明显。当纵向应力由3.2MPa衰减为1.2MPa时，渗流量增长为原来的12倍，且不同部位的环间渗流量差距逐渐扩大，隧道底部的渗流量约为顶部的2倍。在隧道纵向应力松弛后，纵向连接螺栓复紧将极大地降低环缝渗漏水量，螺栓复紧导致环缝渗漏量减小为原来的80%，导致纵向应力达到稳定状态后的环缝渗漏量减小至原来的20%以下。工程实践中，应重视盾构隧道纵向应力松弛对衬砌环间防水性能的影响。

Calculation of circular joint leakage considering the longitudinal stress relaxation along the shield tunnel

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.