Numerical simulation model of artificial ground freezing for tunneling under seepage flow conditions

• Published in: Tunnelling and underground space technology Vol. 92; p. 103035
• Main Authors: Li, Zhiming, Chen, Jian, Sugimoto, Mitsutaka, Ge, Hongyan
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.10.2019; Elsevier BV
• Subjects: Artificial ground freezing; Computer simulation; End well; Engineering; Freezing; Geotechnical engineering; Geotechnology; Ground freezing; Ground stations; Groundwater flow; Laboratory tests; Mathematical models; Moisture–heat coupling; Monitoring; Numerical analysis; Numerical models; Numerical simulation; Phase transitions; Seepage; Seepage flow; Simulation; Soil strength; Soils; Subway stations; Subways; Temperature distribution; Water flow; Seepage flow; Numerical simulation; Artificial ground freezing; Moisture–heat coupling; End well
• ISSN: 0886-7798; 1878-4364
• DOI: 10.1016/j.tust.2019.103035

•A moisture-heat coupling model for artificial ground freezing was proposed.•The model was to quantify the temperature field under various seepage conditions.•The predicted results were in agreement with the monitored results.•An increase in seepage velocity increases the time for freezing curtain formation. Artificial ground freezing (AGF) is a reliable technique for ground improvement to address adverse geotechnical engineering conditions. The formation of a freezing curtain during the AGF process is crucial as it serves to control groundwater flow and enhances the strength of the soil. However, groundwater flow has a considerable influence on the formation of the freezing curtain because it provides a continuous source of heat. Thus, to investigate the influence of water flow on the freezing process during AGF, a moisture–heat coupling model was proposed considering ice/water phase transition to quantify the temperature distribution in soil during the freezing process. The proposed numerical model was further validated using thorough laboratory tests under various seepage flow conditions. Finally, a numerical simulation of AGF was conducted for the end well of the Harbin metro station in China. Five representative monitoring points on the end well were selected and continuously monitored for 30 days to predict the formation of a freezing curtain. It was observed that the temperature results obtained using the proposed model are consistent with actual field monitoring data.