Cooling Performance of a Novel Ventilated Slope on Railbed in Permafrost Regions

The heat absorption of the railbed mainly originates from the embankment slope in permafrost regions. A novel ventilated slope (NVS) with a double-layer convection channel is proposed and verified. By applying this method to the Qinghai-Tibet Railway (QTR), the annual average temperature at the 10 cm depth below the embankment slope surface under NVS was reduced by 4.95 degrees C. The freezing index at the 10 cm depth of NVS was 1.78 times higher than that of the slope without any cooling approaches. The numerical simulation results showed that heat was accumulated for the conventional embankment, while heat was released from the railbed after the application of NVS. With the cooling effect of NVS, the 0 degrees C isotherm would rise above the original natural ground surface in the 2nd year after the embankment construction. A low-temperature region of -2 degrees C would be observed in the underlying permafrost by the 10th year. The underlying permafrost would remain frozen in the 50th year. This study provides a novel method for protecting the underlying permafrost in permafrost regions.