Study On The Evolution Law Of Freezing Temperature Field Of High Velocity Seepage Formation Group Pipes

Artificial ground freezing method has been widely applied in underground engineering,the local groundwater flow velocity in the layer,there will be a frozen wall time increase can’t even form a circle,if continue to use the traditional frozen pipe layout will seriously affect the construction progress,to research,to serve the needs of engineering design and construction.In this paper,by using the self-established hydrothermal coupling physical model test platform and accurately controlling the direction and speed of water flow,an experimental study on the time and space variation of the temperature field of three pipe freezing under multiple flow rates were carried out.Secondly,based on the superposition principle of potential function,the analytical solution of the steady-state freezing temperature field of three pipes under the action of seepage field was deduced.The rationality of the formula was verified by combining the results of physical test model.Then,based on the related theories of heat transfer and seepage mechanics,the hydrothermal coupling numerical calculation model was constructed.Finally,the influence law of the freezing pipe arrangement on the freezing effect was simulated and analyzed by using COMSOL Multiphysics finite element numerical calculation software.Based on the above content,the results show that with the increase of row spacingL,the crossover time and shape stability time both increase.In this paper,eight flow rates of 0m/d,2m/d,4m/d,6m/d,8m/d,10m/d,12m/d and 14m/d are simulated.In the case of no flow velocity,when row spacing L=0.2m and L=0.4m,the freezing wall crossing times are 1070min and 1860min,respectively.There is little difference in area between the two,but the closed freezing wall formed in the case of small distance.When the flow velocity is 2m/d,the intersection time of the two is 1130min and 1950min respectively.The area growth rate of the smaller distance is faster than that of the larger distance.At the intersection time of the larger distance,the area difference between the two decreases to2.1%.At the above 8 velocity,the average temperature of the frozen edge area of 0.2m is not much changed,all of which float in the-8.35℃.The average temperature in the frozen edge area of 0.4m is increasing with the increase of velocity.As a result of the increase of seepage velocity,the size of the distance 1 is reduced,which can reduce the average temperature in the frontal area.Therefore,this study will provide reference for the method of the formation of the flow of the flow.Figure[32]Table[5]References[87]...