Thermal regime in the embankment of Qinghai–Tibetan Highway in permafrost regions

Abstract Based on the data of two groups of ground temperature along Qinghai–Tibetan Highway in permafrost regions in recent five years, this paper analyzes the thermal regime in the embankment in higher and lower temperature permafrost regions, respectively. The results show that the annual mean ground temperature in the embankment is evidently higher than that in the natural ground and the thawing period in the embankment is longer than that in the natural ground, too. In the embankment of higher temperature permafrost regions, talik has formed between the active layer and below permafrost, and the heat flux entering the active layer is in an accumulative state. In both higher and lower temperature permafrost regions, the input of heat into the permafrost below the embankment is greater than the output. The causes of the continual thaw of permafrost in higher temperature permafrost regions are attributed to the ground temperature near 0 °C and the continuous accumulation of heat in the embankment. In lower temperature permafrost regions, the heat entering the permafrost below embankment is mainly to raise the temperature of permafrost for the moment. With the rise of ground temperature, the permafrost below embankment in lower temperature permafrost regions may also be thawed violently.