Evaluation of Thermal Conductivity of Backfill Material

A series of tests have been performed at the Geotechnical Research Centre on backfill material under imposed temperature gradients. It has been demonstrated that the water content distribution during the transient process does not affect the temperature distribution. The Trial Function Technique (TFT) has been applied to calculate the thermal conductivity of the backfill material. Using these values and the proposed method of solution, the temperature profiles have been calculated. The comparison between the theoretically predicted and the experimentally measured temperature profiles shows good agreement except in the vicinity of the heating boundary, where a thin thermal boundary layer exists. The vaporization process in this thin layer contributes to the turbulent effect that can be modeled by using a thermal shock condition.