Numerical Analysis of Soft Surrounding Rock Deformation in Freezing Shaft Sinking based on Temperature Partition

To master the deformation law of soft surrounding rock of well wall during freezing shaft sinking in water-rich area, the distribution of freezing temperature field is simulated with the help of FLAC3D software and isotropic thermal analysis model. The parameters of surrounding rock determined by the actual temperature and the mean temperature of frozen wall are assigned to the model for calculation respectively. The results reveal that the freezing temperature field presents radial gradient distribution, which is in good agreement with the measured data. The double ring freezing scheme can ensure that the frozen wall has sufficient capacity to block water. In the methods of zonal parameter assignment and unified parameter assignment, the maximum radial displacement of the sidewall is 24.91 mm and 42.94 mm respectively, which is located in the lower regional of the excavation area. The volume of the plastic element and the depth of plastic zone reflect the damage degree of surrounding rock. Comparing the simulation results with the measured data, it is more reliable to analyze the deformation law of surrounding rock according to the radial gradient distribution of temperature field.