Experimental Study On Moisture-Heat Transfer Of Artificial Frozen Soil In Deep Alluvium

Combined with the application of artificial ground freezing technology in mine construction,the thickness of the surface layer of the new mine in the two Huai River area is increasing.In this paper,through the theoretical analysis of frozen soil,artificial frozen soil moisture-heat transfer of the experimental study and combined with the engineering example of the double tube freezing model numerical simulation three ways,research on deep stratum soil moisture-heat transfer law system.The results have certain guiding significance for mastering the law of moisture-heat transfer and the deep mine construction.Frost heave test device for large volume of soil through a set of homemade,the moisture content in deep alluvium clay and cold end temperature two factors one-way freezing test under the condition of water,was obtained during soil freezing at different heights of the soil temperature field,moisture field and displacement field the development and change law.For the same soil moisture in deep alluvium rate,the lower the freezing temperature,temperature stable time faster;freezing at the same temperature,soil water content is high,the time required for stable temperature field is long;in the same freezing temperature,soil moisture content the greater the freezing front movement more slow;soil water content is the same,the lower the freezing temperature,freezing rate front is moving faster;In the soil unidirectional freezing process,the soil near the cold source,the basic was frozen in situ,water transport is very small,with the freezing front upwards,the amount of moisture migration of the upper soil moisture increased continuously to the freezing front migration,freezing after still unfrozen water soil body;Test of soil freezing water content,can be found in the same freezing temperature,initial moisture content of large,large amount of moisture migration,initial moisture content is the same,the lower the freezing temperature,the greater the amount of water transfer,water content of the maximum position in near freezing front;In a certain range of moisture content,freezing at the same temperature,frost heave rate increased with the increase of soil water content,linear distribution,higher moisture content of frost heave rate is higher;in a certain range of freezing temperature,initial moisture content of soil at the same rate of frost heave increased with the cold end temperature,linear distribution,cold end the higher the temperature the smaller the frost heaving ratio.Simulation using COMSOL Multiphysics two mode multi coil pipe freezing engineering,compared with the measured value,it can be found that the deflection of freezing pipes has a great influence on the temperature field of frozen wall and the development of tube deflection of freezing,freezing circle is skewed early;The simulation of the temperature field and the frozen wall is basically the same as that of the measured law.The results show that it is feasible to use COMSOL Multiphysics to simulate the development of temperature field in the process of multi coil freezing.