深厚冲积层冻结壁井帮位移发展研究
Study on Displacement Development of Deep Alluvial Frozen Well Wall
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摘要: 冻结壁井帮位移是井筒冻结法施工过程中的重要问题,井帮位移的大小直接影响冻结壁的稳定性,过大的井帮位移甚至会引起冻结管的断裂,从而影响整体施工安全。为了进一步研究井帮位移,借助COMSOL Multiphysics数值模拟软件,考虑地层压力、冻结壁温度、冻土物理参数、力学参数等因素,模拟井筒开挖过程中井帮位移,并结合现场实测数据进行对比。结果显示:在1个开挖的段高中,井帮位移发展前期较大,中期平稳,后期基本无变化;最佳开挖段高为4 m,6 h模拟位移值的井帮位移为32.94 mm,略大于实测的27 mm;模拟结果与实际情况符合程度良好。Abstract: The frozen well wall displacement is an important problem in the construction process of the wellbore freezing method. The size of the well wall displacement directly affects the stability of the frozen wall. Excessive well wall displacement can even cause the freezing tube to break, thus affecting the overall construction safety. To further study the displacement of the well wall, the parameters of formation pressure, frozen wall temperature, physical parameters of frozen soil, mechanical parameters and other factors were used to simulate the well wall displacement during the excavation process with COMSOL Multiphysics numerical simulation software, and compare with the field measured data. The results show that in the high section of one excavation, the development of well wall displacement is relatively large in the early stage, stable in the medium term, and there is basically no change in the later stage. The optimum excavation height is 4 m, and the displacement of the well displacement of 6 h simulated displacement is 32.94 mm, more than the measured 27 mm; the simulation results are in good agreement with the actual situation.