| Summary: | A subway contacting channel project in water-rich weak stratum was constructed by artificial freezing method. Taking that as the research background, the evolution law of soil temperature field was studied in contact channel freezing project by the combination of three-dimensional model test, ANSYS finite element numerical analysis and analytic solution. The results show that the preset temperature -25℃ was reached 12 hours after the freezing test began, and the frozen curtain was formed after 19 hours. According to the time similarity, the active freezing time of engineering field is 50 days, and the maintenance freezing time is 29 days. In the process of soil freezing, temperature changes can be roughly divided into two stages. In the first stage, the soil temperature decreases to 0℃ linearly and rapidly;in the second stage, the temperature continues to drop, with the lowest temperature reaching -15.2℃~-16.8℃ after the soil transformation and exothermic heat release. In the whole process, the soil temperature first decreases fast and then slowly. In the thawing stage of frozen soil, soil temperature gradually rises to room temperature with time, and the whole thawing process takes about 3~4 times as long as the freezing time. The results of finite element numerical analysis show that, unlike the freezing wall temperature outside the freezing coil, the average temperature of the freezing wall inside the freezing coil increases significantly. The analytical solution of double tube freezing temperature field is derived.
|
|---|