Methodology to Determine Thermal Properties of Soils in Cold Regions from Heat-Pulse Migration Characteristics

Abstract

Accurate measurement of the thermal properties (viz., thermal conductivity, thermal resistivity, volumetric heat capacity, and thermal diffusivity) of soils in cold regions necessitates the development of techniques that are robust and efficient and that can incorporate different heat migration mechanisms under the influence of complex initial and boundary conditions. However, devices or the numerical procedures employed to determine them are scanty. In such a scenario, here, a methodology that facilitates the determination of thermal properties of soils in cold regions has been developed based on their heat-pulse migration characteristics (HPMC). To control the temperature of the soil specimen, a temperature-controlled environment chamber has been employed and HPMC was established by using the dual-probe heat-pulse sensor. Furthermore, a technique to estimate the thermal properties of the soil specimen by employing the measured HPMC, which facilitates solving an inverse transient heat conduction problem by using the conjugate gradient method, has been developed. Subsequently, the thermal properties of fine sands corresponding to different initial moisture contents and low temperatures have been determined and the results were compared with those predicted from the HPMC by utilizing interpretation techniques such as the single-point method and nonlinear fitting.