含冰非饱和土壤导热模型构建及应用分析

Construction and Application Analysis of Thermal Conductivity Model of Unsaturated Ice-containing Soil

寒区土壤的导热特性与土壤的组成结构和孔隙数量、大小及其内部物质的相态等因素有关。本文以孔隙度作为代表性状态变量,给出了含冰非饱和土壤的表征单元体(REV)选取方法,建立了2个考虑冻融的条件的含冰非饱和土壤导热分析的REV模型:简化体积加权REV模型和精细体积加权REV模型,据此给出了宏观导热分析模型;并以冬季寒区土壤为例进行了土壤导热分析计算,讨论了含冰非饱和土壤导热系数与相关参数(孔隙率、含水率、含冰率和迂曲度等)的变化特性。本文所建模型,推动了表征非饱和土壤导热特性的方法的进步。

The thermal conductivity of soil in a cold region is related to its composition,the number and size of pores and the phase of materials in pores.This paper presented a selection method of representative elementary volume(REV)for unsaturated ice-containing soil with porosity as the representative state variable.In consideration of freezing-thawing,two REV analysis models(simplified and detailed volume weighted REV model)of ice-containing unsaturated soil were established.The macroscopic thermal conductivity analysis model was given.The soil in the cold region in winter was taken as an example for calculation and analysis.The variation characteristics of thermal conductivity and related parameters(porosity,water content,ice content and tortuosity)of frozen soil were discussed.The model established in this paper promoted the development of methods to characterize the thermal conductivity of unsaturated soils.