Optimization of Double-Ring-Pipe Freezing Scheme for Tunnel Cross-Passage Construction

Abstract

For numerically simulating the phase change of water in ground freezing process, a correct method is proposed in this paper, that the unfrozen water content in frozen soil is taken into account to calculate the enthalpy value at different temperatures. A calculation example of a cross-passage project in shield tunnel shows that the thickness and the average temperature of the frozen wall calculated by this method are very close to the in-situ monitored data. Based on this method, by comparison of the development rate of thickness and the average temperature of the frozen wall according to different design plans, the ground freezing scheme for the cross-passage is optimized for the shortest duration of freeze in agreement with the work standard. The study could enlighten the design for similar projects in the future.