Physics of Techniques for Roadbuilding on Permafrost Essay

3061 Words 13 Pages
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
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Well, possibly nothing. By definition, bedrock that is beneath the freezing point is considered to be permafrost. If this were to thaw, there would be no catastrophic results for the structures that sit on top of it(frozen gravel deposits also remain relatively stable after thawing). When assesing the fragility of permafrost, we must consider the soil type. Much of the perrenialy frozen ground in our region is composed of a silt type material with an extremely high moisture content (30-50 %). In fact, there is so much moisture that there are actualy large hunks of pure ice enveloped by the soil. When ground of this composition thaws, it loses it's strength. Any roads or structures that may sit on the surface are subject to sink, often with devastating results.

Let's say you were going to build a road. You probably wouldn't build it through the middle of a swamp. A swamp is a wet, mushy, unstable quagmere of mud. A road built in these conditions would be sure to fall apart and crumble into ruins in quick time. It would be a foolhardy thing to do.

Yet if the swamp was frozen, and hidden by a facade of shrubs, you would probably build a road over the top. The swamp in its' frozen state would be suprisingly strong, and would have no problem supporting a road embankment. Believe it or not, much of the permafrost encountered in Alaska can be accurately likened to the

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