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Permafrost

Permafrost is a feature of the frigid terrain close to the Earth's poles. It is a permanent layer of underground ice that is not thawed by the brief polar summer, due to the insulating effect of the overlying soil.

Early construction along the Alaska-Canada Highway exposed long sections of permafrost, which melted during the Arctic summer and ruined the roadbed. Road engineers responded by developing roadbuilding techniques that kept the permafrost frozen, such as the use of a thick gravel roadbed that mimicked the natural insulation provided by overlying soil.

References

Garfield (1965)



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