并联式泥水/土压双模式盾构施工技术与冷冻刀盘开舱技术的创新与实践

Innovation and Practice of Parallel Dual-mode Slurry/EPB Shield Construction Technology and Freezing Cutterhead Opening Technology

针对盾构施工过程中经常遇到的2大问题:1)盾构在复杂地层中掘进遇到的盾构选型难问题,如盾构区间一段适合土压盾构掘进,另一段适合泥水盾构掘进,而采用单一掘进模式的盾构都无法应对较大的地层变化;2)盾构在复杂地层、长距离掘进施工时,开舱检查并更换刀具不可避免,盾构在上软下硬/软弱地层/含水砂性地层开舱存在极大的工程安全风险。在原有盾构的基础上,通过采取改造盾构内部结构、搭载冷冻设备、改进设备系统等手段,研制出并联式双模式盾构及搭载冷冻刀盘式盾构。通过广州地铁9号线、广州地铁21号线、220 kV石井-环西电力隧道(西湾路-石沙路段)工程案例,总结出双模式盾构施工技术与冷冻刀盘技术。并联式泥水/土压双模式盾构兼具土压平衡盾构和泥水平衡盾构的功能及施工优势,可根据隧道沿线地表环境条件和隧道穿越地层条件,合理划分采用泥水或土压模式施工的地段,且盾构施工环境适应性强,可在不拆装任何部件的情况下安全、快速地实现掘进模式的切换。将冷冻法与盾构刀盘结合在一起,使盾构刀盘具备冻结地层的功能,通过冷冻刀盘在隧道内对土舱外土层冻结加固,使其达到常压开舱的要求,与双模式盾构相结合,兼容性好,不存在功能上的冲突。

Two major concerns have been drawn in the process of shield construction: one is the difficulty in selecting a shield machine;the other is the high risk of opening for cutterhead changing. Based on the existing shield systems, a parallel dual-mode shield with freezing cutterhead is developed by optimising internal structure and equipment and carrying the freezing device. The dual-mode shield construction technology and freezing cutterhead technology are successfully carried out on project cases including Guangzhou Metro Line 9, Guangzhou Metro Line 21 and 220 kV Shijing-Huanxi Electric Tunnel (Xiwan Road-Shisha Road Section). The parallel dual-mode slurry / EPB shield not only has the functions and advantages of slurry shield and EPB shield but also can switch into slurry / EPB mode for different strata and environments easily. Thus, it can achieve rapid shield tunneling. By combining the shield with the freezing system, the soil around cutterhead can be frozen to provide conditions for chamber opening under atmospheric condition. Meanwhile, it is also compatible with dual-mode shield.