The thermal properties of soils vary because of the different textures of soils; thus, it is valuable to conduct research on the development of thermal conductivity models for soils with different textures. Clay samples with different dry densities and increasing incremental water contents were prepared, their thermal conductivities were measured by the transient plane source (TPS) method. The experimental results show that the thermal conductivity of clay increases with increasing water content and dry density. The water content has a stronger influence than the dry density on the thermal conductivity. This paper presents an improved model to predict the thermal conductivity of unsaturated clay. The model considers the different contributions of minerals in the soil and the distribution of water and air in pores. The accuracy of the model is verified by soil thermal conductivity data that was previously measured and collected from ten regions. Compared with the three similar models proposed in the literature, the new model proposed in this paper has a higher degree of correlation to describe the thermal conductivity of clay.

土壤的热特性因土壤质地的不同而不同。因此，开展具有不同质地的土壤热导率模型的研究非常有价值。制备了具有不同干密度和增加的增量水含量的粘土样品，通过瞬态平面源（TPS）方法测量了它们的热导率。实验结果表明，粘土的导热系数随含水量和干密度的增加而增加。水分含量比干密度对导热系数的影响更大。本文提出了一种改进的模型来预测不饱和粘土的热导率。该模型考虑了土壤中矿物质的不同贡献以及孔隙中水和空气的分布。该模型的准确性通过土壤热导率数据验证，该数据先前已从十个区域进行测量和收集。与文献中提出的三个类似模型相比，本文提出的新模型具有更高的相关度来描述粘土的导热性。