Assessment Method and Impact Range of Lateral Thermal Erosion in Highway Engineering in Permafrost Regions

Abstract

The Qinghai–Tibet Engineering Corridor passes through a 550-km-long permafrost area. The lateral thermal erosion of the linear engineering project inside the corridor substantially influences its stability and serviceability. In this study, the lateral thermal erosion of a road test section of the Qinghai–Tibet Highway underlain by permafrost was validated using long-term monitoring data. Based on the results, the thermal characteristics of permafrost under the road were evaluated by the degree of thermal influence on the permafrost (ΔT), which is the temperature difference between cases with and without road subgrade. The thermal influence range was defined according to the value of ΔT. The zones where ΔT was not equal to 0°C were defined as thermally affected. Conversely, the zones where ΔT was equal to 0°C were defined as thermally unaffected. The influence range and influence extension recognized by ΔT were evidently larger than those by the index of thermal isotherms. The index of ΔT helped identify the zones of heat absorption and release. This method aids in formulating a lateral thermal erosion law for highway engineering in permafrost areas. The findings provide a new way to evaluate the thermal status of permafrost and a reference for the construction and design of linear engineering (roads, railways, etc.) in permafrost areas.