Review of Effectiveness and Costs of Strategies to Improve Roadbed Stability in Permafrost Regions

Abstract

This paper reviews the effectiveness and costs of strategies to improve roadbed stability in permafrost regions, based on a synthesis of literature findings. Roadbeds in permafrost regions experience instability when the embankment loading and its heat absorption properties degrade the permafrost foundation. A variety of engineering strategies are used to mitigate this effect. The review summarizes the rationale, effectiveness, and costs of four types of strategies, namely those that control roadbed thawing, cool the roadbed, insulate the roadbed, and reduce roadbed fill weight. The literature reveals that strategies to control roadbed thawing, insulate the roadbed, or reduce roadbed fill weight do not reverse the long-term degradation of permafrost foundations. Strategies that cool the roadbed by implementing air convection embankments, ventilation ducts, thermosiphons, heat drains, or combinations of these are effective in reducing embankment temperatures and stabilizing the roadbed. Costs vary by geographic and climatic conditions and the proximity of materials to the construction site. Reported data suggest that conducting normal maintenance is less expensive than implementing roadbed cooling strategies, but maintaining serviceability may not be feasible.