Optimization in the Use of Air Convection Embankments for the Protection of Underlying Permafrost

Since the beginning of the 1990s a significant increase in the mean annual air temperatures has been recorded all over the arctic regions. This has lead to a degrading of permafrost, which is now threatening the stability of airport and road embankments. To minimize the damages caused by thaw settlements, different mitigation techniques have been developed. This paper concerns optimization in the use of air convection embankments. In the autumn 2008 a test-site was established during the construction of a new road in Sisimiut, western Greenland. Two types of air convection embankments (ACE) were constructed on shorter sections of the road; a traditional ACE made of crushed rock and a modified ACE, where ventilation pipes were installed in the embankment shoulder. Thermistors were installed in each section to study the annual variations of the thermal regime in the embankments. The results from the first years of monitoring haven't shown the expected effects from installing the ventilation pipes into the ACE. This is probably caused by the systems lack of potential to expel warm air. A higher amount of drainage holes in the ventilation pipes or a new approach instead of pipes will probably lead to the expected results, which has been achieved in earlier laboratory tests.