A field embankment test along the Gonghe-Yushu Expressway in the permafrost regions of the Qinghai-Tibet Plateau

Abstract

Cooling technologies adapting to expressway embankment in permafrost regions have been drawing increasing attention due to its greater permafrost degradation risk; however, none of them has been put into practice. In adaption to the main permafrost-associated challenges of the construction of the Gonghe-Yushu Expressway (GYE) embankment, some new combined cooling technologies were presented. In order to investigate the cooling performance of the newly-presented combined cooling technologies under the conditions of warm and degrading permafrost and wide expressway embankment, an 8.06 km long field embankment test was built along the GYE. In this paper, the configuration and in-situ monitoring systems of 2 newly-presented combined cooling technologies were introduced. Then the working state and cooling performances of the cooling technologies were analyzed through field monitoring data. The first 3 years' monitoring data showed that the ventilation slab (VS) and the heat-induced pavement (HIP) prolonged the lasting period of the natural convection inside the crushed-rock layer (CRL) respectively through decreasing the temperature at CRL top. The CRL embankment, the VS-CRL embankment and the HIP-CRL embankment performed efficiently in preventing an intense permafrost thawing. The field embankment test is expected to supply technical support for construction of other expressways in permafrost regions.