多圈管冻结壁温度场发展及冻结管偏斜影响

Multi-circle-tube frozen wall temperature field development and deviation pipes influence

人工多圈管冻结是深厚地层井筒掘砌的最有效方法,为进一步了解冻结壁温度场发展特性,以某冻结井筒为原型,开展了室内多圈管冻结模型试验,同时借助有限元软件对冻结管无偏斜以及随机偏斜两种条件下冻结壁温度场发展特性进行了分析比较。得出冻结管布置圈径对冻结壁环向扩展速率影响较小;冻结管偏斜对井帮温度、冻结壁有效厚度影响较小,但对不同位置冻结壁交圈时间及对径向方向冻结壁平均温度影响较大;同时冻结管偏斜会使冻结壁内部产生更多的密闭未冻承压水仓,引起冻结壁内部冻胀力增大,对冻结壁整体稳定性产生不良影响。在冻结造孔时,要严格控制冻结管偏斜。

It is well known that artificial multi-circle-tube freezing method could provide better experiences on shaft excavation in deep stratum. For further researching on evolution of the thermal field,the analogy model simulation was carried on,and the temperature field characteristics in frozen wall without freezing tube deviation were analyzed as well as it in random deviation of freezing tube. Comparing the results,it was concluded that the radius of the circular distribution of freezing tube poses slight effects on the annular expanding velocity of the frozen wall,and freezing tube deviation has minor influences on the temperature distribution of the shaft wall and the effective thickness of the frozen wall as well. It has important impacts on the time of frozen wall circle-crossing in different positions and the average temperature distribution in radial direction. In addition,it could result more enclosed confined water storage within the inner of the frozen wall,thereby increasing the heave force inside the frozen wall with negative effects on the stability of the frozen wall. As a result,the freezing tube deviation should be controlled strictly as drilling freezing holes.