液氮冻结盾尾密封加固温度场的数值分析

Numerical analysis of temperature field during liquid nitrogen freezing in high-confined aquifer reinforcement

为解决在含水层跨江跨海盾构隧道施工中盾尾刷破坏后如何更换封水、更换盾尾刷等问题,结合杭州庆春路过江隧道盾尾刷更换工程,利用ADINA大型有限元软件建立三维数值模型,对液氮冻结盾尾密封加固温度场进行数值模拟,研究了温度空间分布及温度随时间变化规律,并对影响冻结温度场的因素进行敏感性分析。通过数值模拟和现场原位实测的对比分析,得出了液氮冻结温度场的变化规律:液氮冻结的时间随着土体导热系数的增大而呈衰减性缩短,随土体容积热容量的增大而呈线性减缓;到达冻结工作面的液氮温度越低,冻结完成的时间越呈衰减性缩短。

In order to solve the problems of how to replace the water,the shield tail brushes and so on.With Qingchun Road cross-river tunnel of Hangzhou as an example,this paper applies ADINA finite element calculation software to compute thermal field for liquid nitrogen freezing 3-D model,studies thermal spatial distribution and the variation laws of temperature with time,and does the sensitivity analysis for influence factors of freezing temperature field.Through the contrast analysis of numerical simulation and field measurement,we get the development regularity of nitrogen freezing temperature field： liquid nitrogen freezing time is shorter along with the increase of thermal conductivity and slowly longer along with heat capacity;the liquid nitrogen freezing temperature is lower,the time of freezing is shorter,which solve the problem of shield brushes tail replacement in high-confined aquifer.