Thermal conductivity changing mechanism of frozen soil-rock mixture and a prediction model

The thermal conductivity of frozen soil-rock mixture (S-RM) is an important parameter affecting its temperature field distribution, and it is also the basic physical parameter for studying the thermal-melting disaster mechanism of S-RM slope in cold regions. However, the effect of ice-water phase change on the thermal conductivity of the frozen S-RM has not been reported. In this paper, the influence of temperatures and rock contents on the thermal conductivity of frozen S-RM were systematically studied by Hot Disk thermal conductivity and NMR tests. Considering the influence of ice-water phase change and high thermal conductivity and inhomogeneity of rock on the thermal conductivity of frozen S-RM, a new effective thermal conductivity (ETC) prediction model of frozen S-RM is established by introducing freezing rate coefficient and weighting ratio. The results showed that the thermal conductivity decreased with the increase of temperature and increased with the increase of rock contents. The correlations of the predicted results are all above 0.97, by calculating the correlation between the predicted value of thermal conductivity and the measured value. The thermal conductivity model has good prediction performance, and can be used to accurately predict the thermal conductivity of S-RM.