The Effect of Embankment Slope Orientation along the Qinghai-Tibet Routes and Related Radiation Mechanism

The Qinghai-Tibet routes(including highway and railway) mainly extend from north to south.Long-term ground temperature observation shows that the temperature under the east-face slope is higher than that under the west-face slope.This is an effect of embankment slope.For the Qinghai-Tibetan routes located in permafrost regions,especially the regions with high ice content,effect of embankment slope orientation causes huge damages to the embankment.This paper focuses on the reasons of the effect of embankment slope orientation developing from the point of view of solar radiation.It is demonstrated that intensive solar radiation,difference of slope orientation and the particular diurnal variety of solar radiation lead to the effect of embankment slope orientation.Finally,some suggestions are proposed to eliminate the effect of embankment slope orientation: 1) to spray or paint material with high albedo on the slopes or the road surface;2) to reduce the thickness of the embankment and decrease the slope gradient of the embankment appropriately.