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Abstract There is a great difference of thermal conductivity between strata in some shaft construction projects by artificial freezing method. An optimization freezing suggestion of flowing two types of negative temperature solutions in a freezing pipe is proposed to accelerate the freezing rate of local strata and to optimize cold energy adjustment. And a single freezing pipe of dual circulation system is developed for this purpose. To verify the effect of intensified freezing and the adjustment ability of the freezing pipe，a single freezing pipe test for sand and silty clay is conducted in a model test box using two sets of circulatory systems to provide calcium chloride solution of different negative temperatures for two sections of a single freezing pipe. Temperature field distribution characteristics of frozen wall in different levels of freezing pipe are analyzed. Meanwhile，the numerical simulation is adopted to calculate temperature field of the case using FLAC3D software. The results show that the difference of temperature can reach 9.1℃ between adjacent outer walls of the two different temperature sections，and the thickness and average temperature of freezing wall can be adjusted effectively. The silty clay has been intensified frozen more than sand certainly.
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Received: 04 October 2012
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2013, Vol. 32 
