Thermal Property Measurements Of Partially Frozen Soils With Single Probe and Dual-Probe Heat Pulse Methods.

Measuring thermal properties of partially frozen soils with the dual-probe heat pulse (DPHP) method has been difficult due to ice melting during heating, in particular at negative temperatures near 0˚C. The single probe (SP) method with small heat application has a possibility to measure thermal properties of partially frozen soils by minimizing the influence of heating. In addition, a numerical inverse analysis of temperature responses to heating with the DPHP method that considers the effect of ice melting during heating may be able to accurately estimate thermal properties in partially frozen soils. Therefore, the objective of this study is to examine DPHP and SP methods for thermal property estimation of partially frozen soils. Thermal properties and dielectric constant of sand, silt loam, and sandy clay loam soils at several moisture contents were measured with thermo-TDR sensors at temperatures ranging between 1 ˚C and -15˚C. Analyses of DPHP and SP measurements with various heat intensities and durations were performed. DPHP data were also analyzed inversely with a numerical model. The strengths and weaknesses of the methods for estimating thermal properties of partially frozen soils were evaluated.