Numerical Simulation of Temperature Field at the Active Freeze Period in Tunnel Construction Using Freeze-sealing Pipe Roof Method

Researchers have put forward a new pre-supporting technique, Freeze-Sealing Pipe Roof method (FSPR), combining Pipe-Roofing method and Artificial Ground Freezing method (AGF).The Gongbei Tunnel, a major part in Zhuhai Link of Hong Kong-Zhuhai-Macao Bridge, is going to employ the FSPR method for the first time in China. We create an innovative freezing scheme with three kinds of freezing tubes (normal, enhancing and limiting tubes) for the FSPR method. In this paper, the temperature field of the schemein the active freeze period is analyzed by numerical simulation, in order to ensure the validity and feasibility. The characters of frozen soil wall have been studied for different strata and controllable parameters. The results show that FSPR can form a frozen soil wall quickly and keep it stable in the different soil layers. In addition, it is indicated that the freezing effect is flexible and controllable.