Study On Temperature Field Of Construction By Freezing Method In Water-rich Cobble Ground

The temperature field of water-rich cobble ground about the subway contact passage construction by freezing method was studied in this paper.Due to the physical factors and clay stratum of water-rich cobble are different from other soil layer,and at present there is less research about the freezing method construction of water-rich cobble ground.Otherwise the construction scheme of other soil layer such as the apply clay layer are significantly different.So we did a related research on the freezing method construction of water-rich cobble ground.In the first place,the theory deduction thermophysical parametes about the water-rich cobble ground were experimentally studied and theory deduced.The thermal conductivity and the formula of specific heat were studied and deduced by experiment,we measure the thermal conductivity about different moisture content.Also the content formula of unfrozen water about the layer was induced in different temperature by reading the literature,and the relation between temperature and the latent heat and enthalpy were derived as an intermediate variable.In the second place,through the analysis method of ANSYS numerical simulation,the temperature field corresponding to the freezing method of the subway contact channel was established by introducing the enthalpy and latent heat into the calculation model.In the calculation model,we considered the heat exchange between the tunnel and the frozen area,and the influence of the tunnel surface on the frozen area.And the model size was set to be much larger than the freeze range of contact channel,reducing the impact of other factors on the calculation model.At last the physical quantities such as the freezing wall thickness,the enclosed time and the average temperature of the freezing zone were obtained in the frozen region at different times in the freezing mode.Under the consideration of design requirements and cost savings,the freezing scheme is optimized by reducing the number of frozen tubes,and the optimized freezing scheme still satisfies the design freeze requirement.And the freezing pipe arrangement scheme for the freezing construction of the subway contact channel in the water-rich cobble formation can be obtained as a reference for the future design and construction.