琼州海峡隧道盾构对接冻土帷幕温度场数值分析

盾构对接冻结法加固时,确定冻结方案、掌握冻土帷幕温度场发展与分布规律等是需要解决的关键问题。依托琼州海峡隧道盾构对接工程,运用有限元软件建立直管冻结和半圆环形冻结两种数值模型,对冻土帷幕温度场的发展规律进行研究,主要得出:两种模型冻土帷幕在各个切片上都能满足设计要求,故在琼州海峡隧道盾构对接时采用冻结法加固是可行的;随冻结时间的增加,两种模型的冻结壁都是以冻结管为中心开始生成并慢慢相交,最后形成封闭的冻土帷幕以达到止水支护效果;直管冻结的冻土帷幕生成时间更短且最终生成的冻土帷幕厚度更厚。所得结果可为今后类似工程设计提供了参考依据。

Numerical Investigation on the Temperature Field of Frozen Curtain in Qiongzhou Strait Tunnel Docking

The key problems of the permafrost curtain when the brazing process is frozen in the development and distribution of the temperature field need to be solved. Based on the shield engineering of Qiongzhou strait tunnel, the numerical model of straight pipe freezing and semicircular ring freezing was established by using the software of finite element. The development of temperature field of permafrost curtain was studied. The results show that the two types of permafrost curtains can all meet the design requirements on the slices. Therefore, it is feasible to use the freezing method to reinforce the shield in the Qiongzhou Strait tunnel. With the freezing time increasing, the frozen walls of the two models begin to generate and slowly intersect with the freezing tube, and finally the formation of closed frozen soil curtains to achieve the effect of water; straight pipe frozen curtains to generate a shorter time and the final formation of the frozen curtain wall thickness thicker. The results also provide a reference for future engineering design with the similar situation.