为解决盾构在低标贯值极软流塑淤泥层掘进中出现的盾构姿态控制困难、管片碎裂、渗漏水、水平收敛超限等问题，依托杭州地铁2号线庆菱路站—建国路站区间隧道，结合现场实践对极软流塑地层中盾构施工的难点进行分析，提出从主机类型、刀盘开口率、主机重心与形心关系等设备选型入手，辅以掘进前的配重、管片超前量控制、设计优化和掘进中的推力分配、同步注浆、土压力和掘进管理，及掘进后的二次注浆、管片拼装和螺栓复紧、拉板拉紧等措施。经杭州地铁6号线枫桦西路站—之江海洋公园站区间、杭海城际铁路工程实践表明，采取上述措施能够有效解决极软流塑地层的盾构施工难题，降低成型隧道渗漏水率，并减小盾构垂直姿态偏差和水平收敛。
The shield will encounter many problems when tunneling
in extremelysoft fluid plastic stratum, such as difficult posture control,
segment fragmentation, water leakage, and over horizontal convergence. As a
result, a case study is conducted on a tunnel between Qingling road station and
Jianguo road station of Hangzhou metro line 2. The construction difficulties of
shield when tunneling in extremelysoft fluid plastic
stratum are analyzed, suggestions are provided regarding host selection,
opening rate of cutterhead, and relationship between host gravity and the
centroid. Techniques such as thrust balance before driving, synchronous
grouting, earth pressure and excavation management, secondary grouting, segment
assembly and bolt retightening, and pulling plate tensioning, are also
introduced. The applicable results of the recommended methods show that the
shield has a good adaptability in extremelysoft fluid
plastic stratum, and water leakage, vertical posture deviation, and horizontal
convergence are reduced.
