Influence of external construction disturbance on the temperature field of frozen soil with liquid nitrogen freezing method

摘要

Based on the advantages of liquid nitrogen freezing method, such as the higher freezing speed, the lower freezing temperature and the larger scale of the frozen soil wall, in the recovering project of a collapse shield tunnel, frozen soil wall was formed between the collapse tunnel and the undamaged tunnel by using vertical liquid nitrogen freezing method. Then the mining excavation proceeded and the construction was completed successfully at last. During the active freezing period of liquid nitrogen freezing, cleaning and draining period of the tunnel, mining period of frozen soil and casting period of concrete, by using the monitored data of frozen soil temperature in the work field, influence of various construction disturbances on the temperature field of frozen soil was analyzed, and influence laws was grasped. What's more, combined proper redistribution of the monitoring holes with informatization construction, the safety of the similar freezing construction can be guaranteed.