小半径曲线地段盾构施工质量调研与分析

Investigation and Analysis of Shield Construction Quality in Curved Area with Small Radius

无锡地铁1号线盾构隧道施工中管片错台与结构渗漏水主要发生在小半径曲线地段。通过小半径曲线地段专项调研与分析,得到了曲线半径、隧道穿越与下卧土层及变坡率与盾构隧道施工质量的关系。根据分析结果,提出了无锡地铁盾构隧道的最小合理设计半径为400m,在穿越土层较好时,其最小设计半径可减小至350m;对小半径曲线段外侧渗漏水的问题提出了合理的壁后补浆治理措施;根据小半径曲线地段施工质量问题分析,提出了综合施工质量控制措施。

In the shield tunnel of Wuxi Metro Line 1,the segment dislocation and leakage mostly occur in section with small radius curve. After the special investigation and analysis,the connection between the construction quality and the three main influencing factors,which are the curve radius,the soil layer in or on which the shield tunnel lie,the ratio of alter gradient,is obtained. According to the study,it is suggested that the minimum suitable curve radius is 400m for the shield tunnel,and it can be reduced to 350 m where the soil layer has good mechanical property; the reasonable grout supplementing measures are provided to deal with the leakage problem occurring in the outside the section of with small radius curve. Based on the analysis of the quality defect in small radius curve,comprehensive construction quality control measures are proposed.