Thermal-seepage coupled numerical simulation methodology for the artificial ground freezing process

This paper proposes a thermal-seepage coupled numerical simulation methodology for the artificial ground freezing (AGF) process using measured soil freezing characteristic curve (SFCC). Firstly, the relation equation between pore ice content and temperature is established based on the measured SFCC, and a thermal-seepage coupled simulation method of AGF is proposed. After that, the performance of the proposed method was investigated based on soil column and large-scale model tests. Finally, the proposed method is compared with the traditional apparent heat capacity method. The results show that: (1) By introducing SFCC, the relation equation between pore ice content and temperature can be established with a clear physical meaning and a direct parameter determination process; (2) The proposed method can reasonably simulate the thermal and hydraulic field of AGF with or without seepage; (3) Compared with the traditional apparent heat capacity method, the proposed method has a conform to physical essence of phase transition and potential heat release and shows comprehensive improvement in theoretical basis, calculation accuracy, robustness and efficiency. Overall, the research results can provide a further understanding and improvement for numerical simulation in AGF.