For the permafrost regions, numerical models are established for analyzing the possible changing tendency of the permafrost thawing features under various surface materials, embankment heights and strikes for a period of 50 years. Surface materials are gravelly and asphalt. Embankment heights range from 0 m to 5.0 m with a step of 0.5 m. For the embankment strike, east to west (EW), southwest to northeast (SW–NE), south to north (SN) and symmetrical route are taken into consideration. The thermal boundary condition is with the assumption that the air temperature will warm up by 1.1 °C during the next 50 years. The calculated results indicate that there is a great difference in thawing features between the asymmetrical and the symmetrical routes. Beneath both the gravelly and the asphalt surfaces, for embankments with south-facing and north-facing slopes, which are defined as the shadowy–sunny slope, calculations show: (1) The maximum thaw depth is closely related to time, the surface materials and the embankment heights. The maximum thaw depths of the low embankments have little to do with the roadbed strike.

 

But the maximum thaw depths of the high embankments are very much influenced by the roadbed strike, and it sharply changes with the variation of the embankment heights and climatic warming. (2)The distance from the location where the maximum thaw depth occurs to the embankment centric line has nothing to do with time, but is closely related to the surface materials, the embankment heights and strikes. Moreover, it is linearly related to the embankment heights. (3) Under the same embankment height and roadbed strike, the distance from the point where the maximum thaw depth occurs to the centric line of the embankment beneath the gravelly surface is larger than that beneath the asphalt surface. However, the maximum thaw depth beneath the asphalt surface is much larger than that beneath the gravelly surface. To some extent, the asphalt surface partially offsets the shadowy–sunny slope effect, but it makes the maximum thaw depth become much larger. (4) When designing an embankment, besides considering the minimum and the maximum embankment height, the shadowy–sunny slope effect also should be taken into account.