地铁联络通道冻结法热传导数值模拟分析

Numerical simulation analysis of heat conduction in freezing method for subway connection channels

以沈阳地铁二号南延线地铁联络通道兼泵房冻结法施工为研究背景,利用有限元分析软件进行三维冻结仿真模拟,在尽可能还原实际现场施工条件下,进行倾斜状冻结管路排布,保温薄板属性参数优化及水平状冻结效果对比。采用倾斜放射状冻结管路模拟分析后,温度以冻结管路为中心,其内部的冻结温度比外部发展更加均匀快速,更早达到规定温度,温度向四周扩散式发展,不断向周围冻结管交圈冻结,直至形成完整的冻结帷幕;温度积极冻结45 d后,冻结壁温度降至-28℃以下,远超规定要求-22℃,可见高性能保温薄板发挥良效;水平冻结管路排布虽可达到规定温度,但对于冻结帷幕发展范围效果不佳。在对同一测温点的数值模拟温度曲线趋势与实际工程的测温曲线趋势基本一致,有效地说明了热传导温度场数值模拟分析研究的可靠性,为实际工程施工提供优良的参考价值。

Taking the freezing method construction of the connecting passage and pump room of Shenyang Metro South Extension Line 2 as the research background,three-dimensional freezing simulation was conducted using finite element analysis software.Under the condition of restoring the actual on-site construction conditions as much as possible,inclined freezing pipeline layout,optimization of insulation sheet property parameters,and comparison of horizontal freezing effects were carried out.Using inclined radial freezing pipeline simulation analysis,the temperature is centered around the frozen joint pipeline,and the internal freezing temperature develops more evenly and quickly than the external temperature,reaching the specified temperature earlier.The temperature spreads around and continuously freezes in circles towards the surrounding freezing pipes until a complete freezing curtain is formed;After 45 days of active freezing,the temperature of the freezing wall decreased to below-28℃,far exceeding the specified requirement of-22℃,indicating that high-performance insulation thin sheets have played a good role;Although the horizontal freezing pipeline layout can reach the specified temperature,it has a poor effect on the development range of the freezing curtain.The trend of the numerical simulation temperature curve for the same temperature measurement point is basically consistent with the trend of the actual engineering temperature measurement curve,effectively demonstrating the reliability of the numerical simulation analysis of the heat conduction temperature field,and providing excellent reference value for actual engineering construction.