Heat transfer processes and thermal performance of a double–layer duct ventilated slope for embankments in permafrost regions

Abstract

The service performance of roadbeds in permafrost regions is primarily governed by the thermal state of the underlying permafrost. To improve embankment thermal management, an efficient air–cooled embankment structure, termed the double–layer duct ventilated slope (DDVS), is proposed to regulate heat transfer and enhance heat dissipation under natural environmental conditions. In–situ tests and numerical simulations were conducted to investigate the heat transfer characteristics, cooling processes, and thermal performance of the DDVS. Results indicate that the DDVS effectively suppresses secondary radiative heating of the embankment and blocks approximately 70% of the incoming solar radiation. Moreover, the DDVS promotes a bidirectional enhanced convective heat transfer process, thereby significantly improving heat dissipation from the roadbed. Compared with the control embankment, the DDVS reduces the annual mean slope soil temperature by 3.9 °C and the average soil temperature approximately 1.2 °C within the upper 7 m depth. The underlying permafrost of the DDVS–protected roadbed remains frozen after 30 service years, thereby ensuring the roadbed long–term stability. Additionally, the incorporation of auto–temperature–controlled wind dampers further improves the cooling efficiency and enhances the climatic adaptability of the DDVS–protected roadbed. These findings provide an effective thermal management strategy and present a novel design for embankments in permafrost regions.