Lateral thermal disturbance of embankments in the permafrost regions of the Qinghai-Tibet Engineering Corridor

Numerous engineering projects have been completed on the Qinghai-Tibet Plateau, and with continued economic growth, additional important engineering projects are being planned. Major transportation construction is largely restricted to the Qinghai-Tibet Engineering Corridor, which is as narrow as a few hundred meters in some places. In this narrow corridor, projects such as the Qinghai-Tibet Railway and the Qinghai-Tibet Highway can influence the stability of the permafrost. We use a numerical model to investigate the individual thermal disturbance caused by the Qinghai-Tibet Railway, the Qinghai-Tibet Highway, and the planned Qinghai-Tibet Expressway. To simulate an upper limit of disturbance under current climate we use the most unfavorable combination of engineering design practices, with unprotected embankments, a traditional ballast embankment for the Qinghai-Tibet Railway, and traditional asphalt pavement embankments for the Qinghai-Tibet Highway and the Qinghai-Tibet Expressway. The lateral thermal disturbance extent of the three projects increases linearly with embankment height. Under the same embankment heights, the lateral extent of thermal disturbance is smallest for the Qinghai-Tibet Railway and is largest for the full Qinghai-Tibet Expressway. The model results provide guidance for minimum distances between the transportation projects to prevent thermal interaction, as a function of embankment height and design. In future research it is important to evaluate the thermal disturbance scopes of other engineering structures, such as tunnels, bridges, and oil pipelines, and to evaluate the thermal interaction and cumulative impact of multiple structures under current and future climate scenarios.