富水砂层盾尾密封修复技术

南昌轨道交通1号线秋水广场站-中山西路站区间隧道为首条穿越赣江的隧道，其始发与接收段均处于富水砂质地层中。在盾构始发过程中，出现盾尾漏浆。为解决盾构推出洞门端头加固体后盾尾漏浆问题，采取泥水舱及盾壳上注入优质膨润土泥浆封闭、盾尾注入水泥砂浆封堵周边水系等措施，根据管片长度与盾尾密封的位置，选择合理的推进长度进行管片拆除，用塞焊的方法对3道盾尾刷处的注浆管、注脂管与盾尾之间的间隙进行焊接封堵，顺利解决了盾尾漏浆问题，完成了盾尾密封的修复工作，可为类似工程的盾尾密封修复提供借鉴与参考。

Case Study on Tail Seal Repairing in Water-rich Sandy Strata

The running tunnel from Qiushui Square to West Zhongshan Road on line 1 of Nanchang Metro is the first tunnel crossing Ganjiang river.The launching and arriving of the shield machine are both located in water-rich sandy strata.In the launching of the shield machine,mortar leakage occurs at the shield tail.High quality bentonite slurry is injected into the excavation chamber to seal the tunnel face and cement mortar is injected at the shield tail to seal the ground water system.Proper thrust cylinder stroke is selected on basis of the segment width and the tail seal positions so as to dismantle the segments.The gap between the grouting pipeline and the grease injection pipeline and the tail skin at the three rows of tail seal brushes is sealed by means of plug welding.In this way,the tail seal is repaired and the problem of mortar leakage at the shield tail is solved successfully.The paper can provide reference for other tail seal repairing in the future.