ABSTRACT
Canada, China and Russia are very large countries, so linear transportation systems are vital to their economy and future development. The simplest form of transportation route across permafrost terrain is the winter road. It ranges from a simple trail across snow-covered frozen ground or the surface of a frozen river to a specially surfaced compacted snow or ice-water mixture along a suitable route. In areas with seasonal frost and those with continuous permafrost, gravel-surfaced roads are adequate and cost effective. They are also the basic form of embankment used for railways and emergency runways, and can be upgraded to paved roads or runways, once they have stabilized. The older methods of construction of embankments used in the 20th century in Russia are similar. However, the layer of rock or gravel to prevent capillary movement of water is mainly used in wet areas. The airfields built over saline marine sediments are particularly problematic. Warming climates have also taken their toll.
