Numerical analysis for the ventilated embankment with thermal insulation layer in Qing–Tibetan railway

The ventilated embankment is widely used in the Qinghai–Tibet railway. In order to decrease heat transfer from embankment downwards to ground when the height of embankment is relatively high, absorbing more heat in warm season, the ventilated embankment with thermal insulation layer is proposed. In this paper, a piece of heat insulator, 20 mm thick, is paved on a plane away 20 cm from the upper surface of ducts. Using finite element method, formulated for non-linear heat conduction, allows the solution of practically any ground freezing problem, the temperature distributions of the ventilated embankment with and without thermal insulation layers are calculated, respectively, on condition that the mean annual air temperature in Tibetan Plateau will be warmed up by 2.6 °C and the mean annual temperature at the native surface is about −1.0 °C in the future 50 years. The conclusions are given in term of the analyzing and comparing results.