Study On The Formation Law Of Frozen Temperature Field In The Liaison Channel Of Nantong Metro Line 2 Under The Action Of Groundwater Seepage

Based on the engineering background of the connecting channel of Nantong Metro Line 2,this paper sorts out the measured brine temperature value,the monitoring value of C1～C5 thermometer hole,In this paper,the contact channel of Nantong Metro Line 2 is taken as the engineering background,and the field measured brine temperature,temperature measuring hole monitoring value of C1～C5,pressure relief hole pressure value of X1～X2 and effective freezing wall thickness are analyzed.In combination with freezing pipe layout and soil layer thermal physical parameters of the actual project,the numerical simulation of No.2 contact channel is carried out by COMSOL.The reliability of the numerical calculation model is verified by comparing the simulated C1～C5 temperature hole with the measured C1～C5 temperature hole in the contact channel.On this basis,the temperature field and the seepage field were coupled by water and heat,the numerical calculation model of the contact channel under the action of groundwater flow rate was established,and the distribution law of freezing temperature field of the contact channel under the action of groundwater seepage was analyzed.The results show that:In the actual situation of freezing hole,when the contact channel is frozen for 10 days without flow rate,the freezing curtain intersects.When the flow rate is 3m/d,the freezing time is 20 d.When the flow rate is 6m/d,the freezing time is 28 d.When the flow rate is 9m/d,the circle will not be turned until 34 d of freezing.With the increase of groundwater flow velocity,the freezing curtain in the upper reaches of groundwater flow becomes weaker and the freezing curtain in the lower reaches becomes thicker.Located on the right axis L of the downstream connection channel of groundwater flow,both sides of the freezing curtain drop to 0℃ after freezing 15 days at 6m/d and9m/d.Located on the left M-axis of the upstream connection channel of groundwater flow,the temperature outside the freezing curtain drops very slowly under the action of high-velocity groundwater,while the temperature inside the curtain drops to 0℃ after15 days of freezing.When the velocity of axis N at the upper part of the contact channel increases,the inner part of the freezing curtain drops to 0℃ faster,while the outer part of the freezing curtain contacts with the soil outside,and the freezing temperature drops slowly.The P axis at the lower side of the connection channel is greatly affected by the flow velocity inside the freezing curtain.The higher the flow velocity,the faster the drop to 0℃.Under the action of groundwater velocity,after the freezing curtain circle,the increase of freezing curtain thickness on the left outer wall and the upper and lower outer walls of the upstream contact channel of groundwater flow decreases.The increase of frozen curtain thickness decreases with the increase of flow velocity,while the increase of inner frozen curtain thickness increases with the increase of flow velocity.Under the same freezing time,with the increase of flow velocity,the thickness of the inner freeze curtain of the left wall and the upper and lower walls increases,while the inner thickness of the right wall decreases and the outer thickness increases,and the inner thickness of the left wall and the outer wall increase most significantly.During the period of freezing stability,the thickness of the frozen curtain increases mainly in the inner side,while the thickness growth rate of the outer side is low due to the influence of groundwater velocity,and the greater the velocity,the smaller the thickness of the frozen curtain.Figure 38 table 8 reference 85...