为解决在长江三级阶地盾构超净距下穿既有线施工沉降控制问题，依托武汉地铁7号线盾构下穿既有运营地铁2号线隧道工程，对下穿工程全过程沉降控制技术进行研究与分析。结合盾构掘进工艺性试验成果，通过方案优化，取消超前管棚预加固，采取对2号线隧道壁后微扰动补偿注浆、管片拉结加固和拼缝密封处理、盾构掘进参数控制、全自动高精度监测信息化施工的综合措施，并辅以克泥效工法，进行下穿既有运营地铁2号线隧道的施工。现场监控量测和施工实践表明： 该下穿工程施工方案非常成功，通过一系列精细化沉降管控措施，实现下穿施工后沉降小于1 mm的控制要求。
To effectively control the settlement of the existing
Wuhan metro line 2 induced by neighboring shield tunneling of metro line 7 in
the third terrace of Yangtze river, the settlement control during the whole
process of the shield tunneling is studied and analyzed. According to the test
results of shield tunneling technology and construction scheme optimization,
the piperoof advance support is cancelled, and the compensatory grouting
behind tunnel wall, segment tensioning and reinforcement, and joint sealing are
conducted to metro line 2. Meanwhile, the shield tunneling parameters are
precisely controlled, highaccuracy monitoring
informationized construction and clay shock method are adopted. The monitoring
and practical results show that a micro settlement less than 1 mm is achieved,
indicating the feasibility of the recommended methods.
