深厚冲积层多圈孔冻结壁温度场发展研究

冻结壁温度场发展是人工冻结法施工在井筒建设过程中最重要的组成部分，对井筒开挖和安全施工有重要的影响。因在地下进行大面积、长时间冻结，土体会发生复杂变化，无法进行相似模拟实验，数值模拟软件成为最直接的辅助工具。本文通过合理的多圈孔布孔方式，考虑钻孔偏斜、冻结过程中水的相变潜热、不同温度下导热系数及热容等影响因素，结合实测数据，运用数值模拟软件COMSOL Multiphysics 建立多物理场耦合对温度场发展进行研究。以某矿西风井深厚冲积层为研究对象，针对91 d冻结壁温度场发展进行模拟。模拟交圈时间为44 d，冻结壁平均发展速度为25.36 mm/d，与实测交圈时间50 d、冻结壁平均发展速度22.72 mm/d相比有微小的误差，模拟结果与实际情况符合程度良好，并推论出以最外圈为主冻结孔对冻结壁发展速度的影响及利弊。综合前人模拟结果，此模拟方法更具有理论意义及工程指导价值。

Development of temperature field of multi circle freezing wall in deep alluvium

The development of the temperature field of freezing wall is the most important part of the artificial freezing method in the shaft construction process,and has a great influence on the shaft excavation and safe construction.Due to the large scale,long term freezing in the underground,the soil undergoes complex changes,similarity simulation experiments cannot be performed,and numerical simulation software becomes the most direct assistant tool.In this paper,through a reasonable multi hole layout method,the main factors,such as drilling deviation,the latent heat of water in the freezing process,the thermal conductivity,heat capacity at different temperatures and other factors,are considered.The development of temperature field with the coupling of multi physics is established by using the numerical simulation software COMSOL Multiphysics with the measured data.The deep alluvium of a west air shaft in a mine was taken as the research object,and the simulation of the development of the 91 d temperature field of freezing wall was performed.The simulation lap time was 44 d,and the average development speed of the freezing wall was 25.36 mm/d.Compared with the measured lap time of 50 d and the average development speed of the freezing wall of 22.72 mm/d,there was a slight error.The simulation results are in good agreement with the actual situation.The study inferred the effect of the outer ring as the main freezing hole on the development speed of the freezing wall.Based on the previous simulation results,this simulation method has more theoretical significance and guiding significance in engineering.