Impacts of snow cover on the cooling mechanism and performance in the crushed-rock interlayer embankment

Most researches assume snow cover as an unventilated thermal resistance to discuss its impacts on the crushed-rock interlayer embankment (CRIE). However, as a porous medium, its role in altering ventilation cooling remains elusive. We developed a numerical model particularly consisting of ventilated snow cover to investigate impacts on the cooling mechanisms and performance of CRIE under climate change. We found that the cooling performance is seriously underestimated if the ventilation of snow cover is ignored. Natural convection and forced convection coexist in cold seasons, and snow cover is conducive to the former, but not to the latter. Snow cover weakens the cooling performance depending on external wind speeds, ambient temperature and relevant properties of snow cover. Before the limit thickness (about 0.5 m) of snow cover, thermal insulation effect would be enhanced with snow cover thickening. On the contrary, it would be weakened and the cooling role increases relatively after the limit. The same goes for total natural convection strength over the entire period of snow cover. Increased snow cover porosity could enhance the cooling performance, while the increase of external wind speeds and extended duration of snow cover might warm the underlying permafrost. The findings provide a valuable reference for its application in snowy permafrost regions.