How DOT mitigates risks when building over permafrost
A scientific research paper was released Tuesday showing that 70 percent of arctic infrastructure is at serious risk from large permafrost thawing over the next 30 years. We spoke to the Department of Transportation about how they work to mitigate these risks when building in the interior.
Regional Material Engineer, Jeff Currey, says that there are four strategies for dealing with thaw-unstable permafrost which is likely to sink down when it warms.
First, if they can, DOT will avoid building on this kind of permafrost. Secondly, they have the option to remove it and replace it with more stable material. Thirdly, DOT can insulate the permafrost to keep it frozen underneath the roads. Or lastly, they can build with conventional methods and accept that there will be degradation needing maintenance.
Currey says a lot of these techniques are very costly, and DOT always has to balance services, safety and cost.
"There are a lot of sections that may never be super highways perfectly flat, perfectly smooth, but if they provide the acceptable level of service and are considered safe enough, then that may be the most cost effective approach to dealing with them," he said.
Currey says two roads where this permafrost degradation is evident are the beginning of the Elliot Highway and the first six miles of Chena Hot Springs Road.