Physics of Techniques for Roadbuilding on Permafrost

Building safe, adequate, durable roads over permafrost soil presents unique challenges to the construction industry. It is not suprising that the mechanisms that lie behind these challenges are explained by the laws of physics. Consequently, as concerned professionals from the engineering community look for inovative ways to deal with the permafrost specter, it is in the realm of physics where they look for the elusive techniques that will enable the extension of the transportation infastructure into the northcountry in a safe, efficient, wise, and economic way.

This paper will explore the techniques used to build road embankments over frozen soil. In exploring these techniques, every effort will be made to demonstrate the physical concept that is pertinent.

But prior to our examination of diferent methods of permafrost resistent roadbuilding techniques we must start by going back to basics. To understand the construction methodology of arctic roadbuilding we need to understand the mechanics and properties of permafrost.

It's All About Heat

* What is Permafrost? Permafrost is defined as ground that has been at a temperature below the freezing point of water for more than two years. A large portion of the ground in Alaska is defined as permafrost (some estimates say as much as 80 percent). Permafrost can extend to a depth of several hundred feet, or it can be as little as several feet deep.

* Is there permafrost in Fairbanks? Yes. We live in an area defined by "discontinuous" permafrost. This classification refers to the fact that some of the ground is frozen, and some of it is not. Also, it is important to note that the permafrost in this area is known as "warm" permafrost. Warm permafrost is at a temperatur...

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...ely be used.

Both of these systems are currently being experimented with. Time will tell if these promising techniques provide an economical means of constructing roads over frozen ground.

Bibliography

Experimental Roadways on Permafrost, McHattie, Esch, Zarling, Conner, Goering, State of Alaska Department of Transportation and Public Facilities, July 1983

ACE and Thermosyphon Design Features Loftus Road Extension Project, Goering, State of Alaska Department of Transportation and Public Facilities, December 2001

Permafrost at the Geological Survey of Canada, http://sts.gsc.nrcan.gc.ca/permafrost/

Alaska DOT Deals With Permafrost Thaws, Stidger, Ruth,Better Roads , June, 2001

Permafrost, A Problem of Building in Alaska, Seibert, Alaska Co Operative Extension Service

The Permafrost Investigation ,Jernstrom, Alaska Housing and Finance Corporation