聚氯乙烯盐水冻结管在盾构进洞中的工艺性能分析

On the Technology of PVC as Brine Freezing Pipe in the Shield Tunnel Construction

在地铁隧道盾构进出洞采用冻结法加固工程中,由于盾构机多为软土盾构,刀盘无法切除打入土体的钢质冻结管。为了解决盾构进出洞免拔管问题,采取PVC(聚氯乙烯)管作为冻结管,进行盾构进洞免拔管盐水冻结加固工艺性试验。分析了冻结过程中PVC冻结管在低温盐水冷冻下的渗漏性,冻结管管壁和冻土壁的温度分布规律,以及盾构推进过程中PVC冻结管的可切割性。获得了PVC管作为盐水冻结管的可行性。

Urban tunnel shielding normally uses the freezing method to reinforce the construction, since the shield ma- chine is installed with soft soil cutter, but it cannot resect the frozen steel pipe in the soil. In order to solve the prob- lem of extracting the freezing pipe when the shield comes in and out of the tunnel, PVC pipe is adopted as the freez- ing pipe, a test of extract-free pipe is carried out with a shield going into the tunnel. In this paper, the PVC pipe seepage at low temperature brine during the freezing process, the distribution of the wall and the freezing pipe temperatures, and the cutting property of PVC frozen pipe in the shielding process are analyzed. PVC pipe used as brine freezing pipe is proved satisfactory, and this study provides certain reference values for using PVC pipe as freezing pipe.