A modified calculation model for the saturation-dependent thermal conductivity of fine-textured soils

Abstract

Thermal conductivity of soils is an important parameter in heat and water transfer analysis of soils. Here, a modified model was proposed to calculate the saturation-dependent thermal conductivity of fine-textured soils from the completely dry condition to the full water saturation. In the study, we developed a new parallel-series model for calculating the thermal conductivity of soils at the completely dry condition with a weighting parameter. The weighting parameter can be calculated using the ratio of the thermal conductivity of air to the thermal conductivity of solid grains. We also proposed a simplified equation to calculate the parameter a of the model proposed by Bi et al. using sand content and thermal conductivity of soils at the full water saturation. Substituting the new parallel-series model and the simplified equation for the parameter a into the model proposed by Bi et al., yielding the modified model. The modified model was evaluated with 14 soil samples. Results show that the modified model could well estimate the thermal conductivity from the completely dry condition to the full water saturation. Keywords: Thermal conductivity, Saturation-dependent, Parallel-series model, Weighting parameter