变管径冻结管对地铁联络通道冻结温度场的影响分析

Influence of Variable Diameter Freezing Pipe on Freezing Temperature Field of Subway Connecting Passage

在地铁联络通道的冻结法的设计与施工中,冻结管通常为倾斜放射布置;这导致联络通道不同横截面冻结管间距不同,最终引起冻结温度场的不均匀发展。以郑州地铁5号线联络通道为背景,在冻结管内盐水流量不变的情况下,对现行冻结管做出调整。通过改变冻结管尺寸来改变管内的盐水在不同位置的流速,从而改变冻结管不同截面的对流换热系数,使联络通道的冻结温度场得到均匀发展。利用ADINA数值分析软件对联络通道冻结法设计建立三维模型,分析改变管径后,整个冻结过程中联络通道各个截面温度场的发展情况。结果表明,在同一冻结工程中,联络通道各个截面的冻结壁厚度及冻结平均温度趋于一致;且冻土交圈完成的时间得到了缩短,这表明通过改变冻结管的尺寸能够显著改善冻结温度场的不均匀发展问题。

In the design and construction of subway connecting passage by freezing method,the freezing pipes are usually arranged with inclined radiation.This leads to different distances between freezing pipes in different cross-sections of the connecting passage,and eventually leads to uneven development of the freezing temperature field.Taking the connection passage of Zhengzhou Metro Line 5 as the background,under the condition that the flow rate of brine in the frozen pipe is unchanged,the current frozen pipe is adjusted,and the velocity of brine in different positions is changed by changing the size of the frozen pipe,so that the convective heat transfer coefficient of different sections of the frozen pipe is changed,and the frozen temperature field in the connection passage will be developed evenly.The ADINA software is used to build a three-dimensional model of the connection passage constructed by freezing method,and the development of the temperature field of each section of the connection passage during the whole freezing process is analyzed after changing the size of the freezing pipe.The results show that the thickness of the frozen wall and the average frozen temperature of each section of the connecting passage tend to be the same in the freezing engineering,and the intersection time of the freezing wall be enclosed is shortened,which indicates that the uneven development of the frozen temperature field can be significantly improved by changing the size of the frozen pipe.