Effective Thermal Conductivity of Partially Saturated Soils: Analytical Micromechanics Approach

The chapter delves into the critical role of thermal conductivity in ground media, particularly in the context of sustainable civil engineering practices. It builds upon existing models and addresses their limitations, such as the need for difficult-to-measure parameters or the inability to cover the full range of saturation degrees. The authors propose a new approach that simplifies the complex inverse problem of determining soil microstructure, using a matrix/inclusion type microstructure and the Mori–Tanaka approximation scheme. A key innovation is the introduction of θ(Sr) functions for water and air inclusions, which vary with the degree of saturation. The chapter presents preliminary findings that demonstrate the effectiveness of this approach, particularly for coarse-grained soils. It also explores the possibility of using a single θ(Sr) function for both water and air, further simplifying the model. The authors discuss the potential of this approach to develop a universal model for thermal conductivity in unsaturated soils, paving the way for future research and applications in sustainable energy extraction from ground media.