Relating thermal conductivity of soil skeleton with soil texture by the concept of "local thermal conductivity fluctuation"

The thermal conductivity of the soil skeleton lambda(s) is an essential parameter from the point of view of the correct assessment of soil overall/effective conductivity. This work introduces the concept of "local thermal conductivity fluctuation" which characterizes the microscale variation of conductivity within the solid phase. It is proposed to link the "local fluctuation" of thermal conductivity lambda with the soil texture - the information that is available at the scale of engineering applications. It was possible to relate the skeleton thermal conductivity with the grain size distribution of the soil. Finally, based on a large series of numerical simulations, the paper provides four triangle diagrams (at different organic matter contents: 0%, 2%, 4% and 6%) relating the value of lambda(s) with volume fraction of individual soil separates. This result is extremely important from the practical point of view. One can quickly evaluate lambda(s) value provided that information on the grain size distribution and organic matter content is available. (C) 2022 Institute of Rock and Soil Mechanics, Chinese Academy of Sciences. Production and hosting by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).