1 Section for Geotechnics and Geology, Department of Civil Engineering, Technical University of Denmark2 Department of Civil Engineering, Technical University of Denmark3 Section for Arctic Technology, Department of Civil Engineering, Technical University of Denmark4 Arctic Technology Centre, Center, Technical University of Denmark5 Universite Laval6 Universite Laval
Roads and airfields in the Arctic
The presence of permafrost is an important aspect in civil engineering in arctic regions. The construction of engineering structures, such as road and airfield embankments, will change the thermal regime of the ground, and may lead to permafrost degradation under or adjacent to such structures. This problem, has in the last decades, been amplified by the climate warming, which has been most evident in the arctic regions. The construction of a road embankment usually results in an increased mean annual surface temperature, which will increase the thawing of permafrost and expose the road embankment to thaw settlements. To avoid or at least minimize the damages caused by thaw settlements, different mitigation techniques have been developed. This thesis concerns laboratory tests and field studies of three mitigation techniques: air convection embankment, heat drain and reflective surfaces. The main objective has been to study the three above-mentioned techniques and evaluate their potential for minimizing the problems with thaw settlements in permafrost areas. The air convection embankment and heat drain techniques have been tested for the implementation in the shoulders of road and airfield embankments. Both methods will allow cold air to penetrate the embankment from the bottom, while warm air is dissipated at the top. The results from the test-site at Tasiujaq Airport (Nunavik, Québec, Canada) showed that both techniques will cause a decrease in the mean annual temperature at the sub-grade level, which will minimize permafrost degradation underneath the embankments. Ground Penetrating-Radar (GPR) has been used to study the effectiveness of the use of reflective surfaces on the depth of the frost table throughout a complete thaw-freeze season in Kangerlussuaq Airport (Greenland). The results showed that the use of a reflective surface (white paint) will reduce the thickness of the active layer and avoid permafrost degradation underneath the embankment. This should promote the interest in the development and use of light-colored asphalt pavement materials.