Long-term thermal stability study of the typical embankment along the Qinghai-Tibet Railway in warm permafrost regions北大核心CSCD

Using the long-term ground temperature monitoring data of the permafrost zone along the Qinghai-Tibet Railway from 2006 to 2020，three types of typical roadbed structures were analyzed. Traditional embankment（TE），U-shaped crushed rock embankment（UCRE）and crushed rock revetment embankment（CRRE）were included the three types of typical roadbed，which were selected to the long-term monitoring sections within the warm permafrost zones. The evolution of ground temperature field，mean annual ground temperature （MAGT）and annual maximum ground temperature（AMGT）in the depth range of 20 m under the embankment were analyzed and studied since 15 years of operation. The monitoring and analysis results show that：the growth rate of MAGT under the left and right shoulders of the TE is always higher than that of the same depth in the natural site. The MAGT under the UCRE is always lower than the natural site and always maintains a certain difference，whereas，the difference in ground temperature under the left and right shoulders is also not negligible. The MAGT of the left shoulder in the CRRE is not much different from that of the natural hole，while the MAGT of the right shoulder is always lower than that of the natural hole，and the differ in ground temperature between the left and right shoulders is smaller than that of the UCRE. The artificial permafrost table（APT）under the TE is always lower than that of in the natural site. Both the UCRE and CRRE，the APT in the left and right shoulders of them has been elevated into the embankment，and the differ of APT between the left and right shoulders is about 1. 0~1. 5 m. the differ of APT between the left and right shoulders in the CRRE is slightly lower than that of UCRE. Overall，because of the influence of thermal disturbance about engineering and climate warming，the TE in the warm permafrost zones cannot keep the thermal stability of permafrost under the embankment. Some active-cooling and reinforcement measures need to be taken. Both of the UCRE and CRRE，have a certain active-cooling effect on the permafrost under embankment，but the differ in ground temperature between the left and right shoulders still needs to be taken seriously. © 2022 Science Press (China).

Long-term thermal stability study of the typical embankment along the Qinghai-Tibet Railway in warm permafrost regions

Using the long-term ground temperature monitoring data of the permafrost zone along the Qinghai-Tibet Railway from 2006 to 2020， three types of typical roadbed structures were analyzed. Traditional embankment （TE）， U-shaped crushed rock embankment （UCRE） and crushed rock revetment embankment （CRRE） were included the three types of typical roadbed， which were selected to the long-term monitoring sections within the warm permafrost zones. The evolution of ground temperature field， mean annual ground temperature （MAGT） and annual maximum ground temperature （AMGT） in the depth range of 20 m under the embankment were analyzed and studied since 15 years of operation. The monitoring and analysis results show that： the growth rate of MAGT under the left and right shoulders of the TE is always higher than that of the same depth in the natural site. The MAGT under the UCRE is always lower than the natural site and always maintains a certain difference， whereas， the difference in ground temperature under the left and right shoulders is also not negligible. The MAGT of the left shoulder in the CRRE is not much different from that of the natural hole， while the MAGT of the right shoulder is always lower than that of the natural hole， and the differ in ground temperature between the left and right shoulders is smaller than that of the UCRE. The artificial permafrost table （APT） under the TE is always lower than that of in the natural site. Both the UCRE and CRRE， the APT in the left and right shoulders of them has been elevated into the embankment， and the differ of APT between the left and right shoulders is about 1.0~1.5 m. the differ of APT between the left and right shoulders in the CRRE is slightly lower than that of UCRE. Overall， because of the influence of thermal disturbance about engineering and climate warming， the TE in the warm permafrost zones cannot keep the thermal stability of permafrost under the embankment. Some active-cooling and reinforcement measures need to be taken. Both of the UCRE and CRRE， have a certain active-cooling effect on the permafrost under embankment， but the differ in ground temperature between the left and right shoulders still needs to be taken seriously.