Abstract：In order to prevent embankment from absorbing heat in hot season，the ventilated embankment with thermal insulation layer is proposed. The thickness of heat insulator is 20 mm and paved 20 cm above upper surface of ducts. The finite element formulae are derived from the differential equation of three-dimensional temperature fields involving phase change by Galekin method. The temperature distributions of the ventilated embankment with and without thermal insulation layer are calculated respectively under the case that the annual mean air temperature in Qinghai-Tibet Plateau will be warmed up by 2.6℃ in the future 50 years and the mean annual temperature at the native surface is about －1℃. The results indicated that the insulation layer reduces little absorption of heat for permafrost under embankment in the case and the effect of heat insulation is not so good. The conclusions are given in term of the results of analysis and comparison.
