Thermal effect of thermokarst lake on the permafrost under embankment

Abstract

In permafrost regions of the Qinghai-Tibet Plateau, road disaster caused by permafrost degradation cannot be ignored. As a common thermal disaster in permafrost regions, thermokarst lake has serious thermal erosion on permafrost and results in permafrost degradation aggravating. This study focused on two subgrade cross-sections of Gonghe-Yushu Highway in the Qinghai-Tibet Plateau to analyze thermal effect of thermokarst lake on the permafrost under embankment. The analysis infers that thermokarst lake can transfer heat to permafrost under the embankment, as a heat resource, and the heat flux decreases with the distance away from thermokarst lake in horizontal and vertical direction. Thermokarst lake can cause average ground temperature of permafrost under the embankment increasing, and with less distance from the thermokarst lake the temperature increases more severely. Thermokarst lake results in 14 m thickness melting interlayer in soil under lake and change shape of melting area.