Assessment of the effectiveness of two heat removal techniques for permafrost protection

Abstract

Two mitigation techniques, an air convection embankment and an embankment of a granular material with an integrated heat drain, have been tested for the implementation in the shoulders of road and airfield embankments in permafrost regions. Both techniques will allow cold air to penetrate the embankment from the bottom, while warm air is dissipated at the top. The techniques have been tested in the laboratory, where a small-scale embankment (SSE) was build and placed in a cold room to measure the embankment temperatures during winter conditions. A numerical modeling has been developed and calibrated on the SSE to verify the effects on the thermal regime of full-scale embankments. The results have shown that both techniques will cause a decrease in temperature, which will minimize or even possibly avoid permafrost degradation underneath the embankments. The laboratory results have also shown that the effectiveness of the air convection embankment technique can be increased during winter conditions by ventilating the top and the bottom of the embankment shoulders. Installation of air intakes along the shoulders will facilitate air flow into the system during winter and will trap the cold air in the bottom of the embankment through the summer period. This solution has been verified using the numerical model.