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, the freeze-sealing pipe roof method (FSPR), combining the pipe-roofing method and artificial ground freezing method (AGF). The Gongbei Tunnel, a major part in the Zhuhai Link of the Hong Kong-Zhuhai-Macao Bridge, is going to employ the FSPR method for the first time in China. We created an innovative freezing scheme with three kinds of freezing tubes (normal, enhancing and limiting) for the FSPR method. In this paper, the temperature field of the scheme in the active freeze period is analyzed by numerical simulation in order to ensure the validity and feasibility. The characteristics 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.