软土地层单排管冻土帷幕温度场分析

Analysis of Temperature Field of Freezing Soil Curtian in Soft Soil with One Row of Pipes

人工冻结法施工技术是软土地区隧道施工的一种经济可靠的方法,在上海地区得到了多次成功应用。不过,由于计算理论的不完善,也出现过诸如上海地铁四号线透水的重大工程事故。在冻结法施工过程中,冻土帷幕的温度场分析是非常重要的环节。作者对冻土的物理和力学性质作了相关的定性分析。通过相关的研究资料和实验数据总结了具有实用意义的单孔和单排孔温度场温度计算理论公式,并运用Ansys有限元软件,结合上海长江隧道工程冻结法施工的相关施工数据,建立了单排冻结孔数值计算模型。通过理论计算值、数值计算值和实际监测信息的比较,得出了单排孔冻结帷幕温度场发展变化的相关规律。

The artificial ground freezing technique, that has been used successfully and frequently in Shanghai, is an economical and reliable method to dig metro tunnels in soft soil. However, without theoretical calculation, there were accidents such as the water inrush in Shanghai Subway Line 4 occurred. In freezing, the control of thickness of the freezing wall is of great importance. The physical and mechanical properties of the freezing soil is analyzed qualitatively in this paper. Based on related research materials and experimental data, this paper developed theoretical formulas for calculating temperature of freezing soil either with one single freezing pipe or with one row of freezing pipes. It applied the software of Ansys to build a numerical model with one row of freezing pipes, combined with the related construction parameters in Shanghai Changjiang Tunnel. By comparison of the calculation outcome derived from theoretical formula, numerical method and monitoring data, some laws about the changes of temperature field of freezing soil curtain with one row of freezing pipes are found.