Predicting the thermal conductivity of red-bed soil based on multiphase medium

Red-bed soil is a widely existing type of soil, and its thermal conductivity represents a fundamental indicator of thermodynamic behavior and plays a vital role in numerous civil engineering applications. In this study, a predictive model is developed to estimate the thermal conductivity of red-bed soil. The model begins with the derivation of an expression for the equivalent thermal conductivity of a three-phase porous medium based on Wiener’s boundary theory. Following this, a series of experiments are performed, including specific heat capacity tests on three remolded soil samples and thermal conductivity tests carried out under two water contents (0% and 10%). In these tests, three different porosity and saturation conditions are adjusted through compaction cycles. Based on the experimental results, numerical simulations are then carried out using a point heat source to explore how thermal conductivity varies with changes in porosity and saturation levels. Finally, a predictive model is constructed based on these findings. The results indicate that this predictive model provides good predictions of thermal conductivity under various scenarios and achieves satisfactory application effects.