Geotechnical Engineering in Antarctica
Sam Mackenzie, Coffey Geosciences
At least three Australian Geotechnical Engineers have visited Antarctica in the past eight years to conduct geotechnical investigations. Most recently, Sam was contracted by the Australian Antarctic Division to visit Davis Station for a period of five months over the 2002/2003 summer. The specific geotechnical issues associated with development in the cold regions of the world are probably unfamiliar to most Australian Engineers. Even in Scandinavia, Russia and North America, the field of permafrost engineering is relatively specialised and somewhat hidden behind a mass of strange terminology. A number of projects are being undertaken or considered, including wind turbine generators, an air strip for a business jet as well as a wastewater treatment plant, water storage tank and several buildings. Geotechnical assessment included consideration of periglacial geomorphology and metamorphic geology and their influence on drainage, erosion and foundation conditions around the station. Particular attention was paid to ground movements related to cryoturbation. That is, frost jacking, freeze/thaw movement and thaw settlement. The presence and potential of thawing ice rich permafrost beneath existing and proposed buildings required careful consideration of foundation options and ground insulation measures. Despite the harsh environment and potential for freeze/thaw related ground movement, the solution to most geotechnical issues was fairly simple due to the abundance of thaw stable gneiss bedrock, dry climate (only 75mm/year precipitation), low mean annual air temperature and almost complete lack of organic and clay soils.
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