ABSTRACT
The thermal properties of soils can be an important parameter in the design of heat storage systems, ground source heat systems, high level nuclear waste isolation, energy piles, thermal ground improvement techniques and buried pipelines. The Thermal Conductivity of soils depends on a number of factors, including grain-size distribution, soil composition, salt content, organic matter, Water Content and Voids Ratio. Several empirical methods are available to estimate Thermal Conductivity of soils from various compositional parameters; however, there is a simple laboratory method that can be used to measure Thermal Conductivity directly.
Unlike some materials, such as water, steel and aluminum, the Thermal Conductivity of soils is not a material property. Since soils consist of mineral matter, water and sometimes air, the thermal Conductivity depends on composition (grain size and mineralogy), Unit Weight or Porosity/Voids Ratio, Water Content and the degree of Saturation. Many studies have been performed in the laboratory and field to determine the Thermal Conductivity of a wide range of soils.
