Evaluation of EPS application to embankment of Qinghai–Tibetan railway

In many cases, protecting permafrost from further thaw due to human activities might be the first choice for embankment design in permafrost regions. The observation data of an embankment with insulation at the Beiluhe site are analyzed. Two-dimensional finite element analyses are conducted, in which phase change is taken into consideration to simulate the thermal regime of the Qinghai–Tibetan railway with expanded polystyrene (EPS). Based on the predicted maximum thaw depth in the following 50 years, the best position for insulation is presented and the relationship between the thickness of insulation and the height of embankment is analyzed. Also, the applicable range of insulation in embankment engineering of the Qinghai–Tibetan railway in terms of mean annual air temperature (MAAT) is suggested and the influence of the geothermal field of permafrost on the applicable range of the insulation is discussed.