Artificial Freezing Method In Subway Tunnel Construction Research And Application

With the rapid development of underground space engineering,the previous excavation methods have been unable to meet the needs of complex projects,so artificial freezing method came into being.Artificial freezing method because of its small impact,short duration,practical strong shield has become the level of communication channel construction important means of support.In the past,often in the mine construction using artificial freezing method construction technology to freeze the soil around the formation of frozen soil excavation,to today’s urban subway tunnel contact channel in the excavation depth,construction technology and construction environment and the mine has a relatively large difference,so Some design and research methods are also different.At present,there are still some gaps in the construction process of the artificial freezing method,so there is not a lot of research on the freezing field of the channel,and the development law of the frozen temperature field is not thorough enough.In this paper,the whole process and physical properties of permafrost formation are described from the basic theory of artificial soil freezing.The mathematical model of freezing temperature field is used to deduce the average temperature formula and the width of cooling zone.The freezing temperature field of the communication channel is simulated by finite element ANSYS software,and the temperature field cloud image and the permafrost are obtained at different time.The temperature field of the tunnel is analyzed by finite element ANSYS software.The distribution of the temperature field and the formation process of the frozen soil curtains in the horizontal freezing process of the contact channel are studied deeply,and the freezing time of the different sections and the thickness of the frozen soil walls are obtained.Maintain the freeze to provide reference.In addition,the freezing effect is analyzed from three paths,the reasons for the different effects of freezing on different paths are analyzed,and the rationalization suggestions are put forward.According to the measured data,the formation of permafrost curtain is compared and compared with the simulated numerical value,which indicates that the transient freezing temperature field obtained by numerical simulation can reflect the actual situation of the project.