铁道科学与工程学报2025，Vol.22Issue(1)：307-319,13.DOI:10.19713/j.cnki.43-1423/u.T20240484
高流速富水砂层地铁隧道液氮冻结温度场演化规律研究
Evolution law of liquid nitrogen freezing temperature field in subway tunnel with high flow rate and water-rich sand layer
摘要
Abstract
Groundwater seepage frequently poses significant challenges to metro tunnel construction.Traditional saltwater freezing method is inadequate for high flow rates,whereas employing liquid nitrogen at ultra-low temperatures rapidly stabilizes and reinforces the sand layer.Therefore,it is crucial to conduct a comprehensive hydrothermal coupling analysis to investigate the evolution of the liquid nitrogen freezing temperature field under seepage conditions.Based on the principles of energy and mass conservation,a numerical model coupling the liquid nitrogen freezing temperature field with the seepage field was established to study the development of the freezing temperature field and the closure time of the freezing curtain under different seepage velocities.The results show that the closure times of the freezing curtain for seepage velocities of 10,12.5,15,17.5,and 20 m/d are 5.76,6.85,8.31,11.43,and 18.57 days,respectively.The closure time increases exponentially with the seepage velocity.By fitting the simulation data,a predictive formula for the closure time of the freezing curtain under seepage conditions is derived,and the limiting flow rate is calculated to be 22.26 m/d.Seepage causes inhomogeneity in the freezing curtain,with the ratios(Rd/Ru)for seepage velocities of 10,12.5,15,17.5,and 20 m/d being 1.23,1.35,1.53,1.76,and 2.12,respectively.The analysis of the liquid nitrogen freezing process indicates that the'adjacent pipe effect'occurs when the freezing front is reduced to Lj,enhancing the expansion of the freezing front,accelerating the intersection of the frozen curtain.The convective heat transfer caused by seepage weakens the'adjacent pipe effect',resulting in a decrease of Lj with increasing seepage velocity.The Lj values corresponding to seepage velocities of 15.0,17.5,and 20.0 m/d are 389,355,and 254 mm,respectively.These findings can provide valuable guidance for the construction of subway tunnels using the liquid nitrogen freezing method under high flow velocities.关键词
液氮冻结/大流速/数值模拟/水热耦合/邻管效应/冻结帷幕Key words
liquid nitrogen freezing/high flow rate/numerical simulation/hydrothermal coupling/adjacent pipe effect/freezing curtain分类
交通工程引用本文复制引用
杨哲,蔡海兵,王彬,李孟凯,庞昌强..高流速富水砂层地铁隧道液氮冻结温度场演化规律研究[J].铁道科学与工程学报,2025,22(1):307-319,13.基金项目
国家自然科学基金资助项目(52378384) （52378384）
安徽省自然科学基金资助项目(2308085ME188) （2308085ME188）
河南省地下工程与灾害防控重点实验室开放基金资助项目(KFKT2023-06) （KFKT2023-06）
