A previous laboratory test carried out by the authors proved that the addition of ventilation ducts can efficiently enhance the cooling effect of crushed-rock interlayer. The mechanism revealed by the laboratory test was that,the ventilation ducts intensified natural convection and thus enhanced cooling effect of the crushed-rock interlayer by decreasing its upper boundary temperature. In this research, to further enhance the cooling effect of the crushed-rock interlayer, the ventilation ducts were perforated and then positioned at the upper boundary of the crushed-rock interlayer. Two crushed-rock interlayer embankments with perforated and imperforated (ordinary) ventilation ducts were tested under the same test conditions. The analysis of the temperature characteristics of the two test crushed-rock interlayer embankments with perforated and imperforated ventilation ducts showed that the crushed-rock interlayer embankment performed amore efficient cooling effect when the ventilation ductswere perforated. The effect was straight forward: the addition of the perforation on the ventilation ductwall let the air that was flowing through ventilation ducts partially penetrated into the crushedrock interlayer. The result was that, during negative air temperature period, the upper boundary temperature of crushed-rock interlayer was decreased to a great extent, and consequently natural convectioninthe crushed-rock interlayerwas intensified. The cooling effect during negative air temperaturewas efficient enough to restrict the heat injected into the embankment during positive air temperature period. On the whole, the crushed-rock interlayer embankment with perforated ventilation ducts has a good cooling effect to the underlying permafrost.Based on these, the new type of embankment is recommended in the construction of large-width highways in permafrost regions in the future.

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