| Brine freezing method is one of the formation water proof and ground reinforcement methods,but freezing wall develop very slowly or doesn’t close in saturated sand with groundwater flow condition,nitrogen freezing method can solve groundwater flow problem quickly.Combined with pipe adopted frequently in municipal construction,this paper chooses the seepage ground of saturated sands as the object of study.The study on the development regularity of the freezing temperature field of nitrogen freezing under the action of seepage was conducted by the methods of numerical calculation and physical experiment.Considering the non-uniformity of nitrogen freezing,numerical calculation was conducted to study the temperature distribution of freezing pipe,and the element model with structure analysis of Comsol was built acordong to real situation.Coupling of seepage field and temperature field was conducted by PDES in Comsol.The development regularity of the freezing temperature field of different pipe temperature and groundwater flow velocity under the action of seepage has been analyzed by one-pipe freezing experiment.The development regularity of four-pipe under the action of seepage has been analyzed by typical factor experiment.The relationships between the freezing wall thickness,average temperature,closure time and the groundwater flow velocity,spacing of freezing pipe,pipe temperature,groundwater temperature were analyzed by the single factor experiments.The influence and significance of various factors on the seepage-temperature field were analyzed by orthogonal experiment.Physical simulation experimental has been studied according to similar criteria,the regularity of the freezing wall thickness was calculated by the changing of temperature of measuring points.Pipe temperature of physical simulation experimental was restored to prototype according to similar criteria,and the reliability of numerical calculation was tested by the comprehensive analysis. |
