Solid phase thermal conductivity model of alpine meadow soils based on fractal theory

The determination of thermophysical parameters is crucial in the hydro-thermal coupling calculations of permafrost. Alpine meadows can affect the heat exchange inside and outside the soil due to the well-developed root, which can have an impact on the stability of permafrost. At present, the research on the thermal conductivity of alpine meadows is less, and most of the research focuses on the thermal conductivity of rock and soil. In this paper, according to the distribution and development characteristics of roots in the soil, a theoretical model of thermal conductivity of root-soil in alpine meadow based on thermal resistance is established by using fractal theory. The reliability of the theoretical model was verified by introducing the established solid-phase thermal conductivity model into the geometric mean model. The effects of the ratio of root area to total area(RRATA), tortuosity fractal dimension, and area fractal dimension on thermal conductivity are analyzed. The model constructed in this paper provides a theoretical basis for further research on the physical model of thermal conductivity of meadow porous media.