Cooling effect analysis of temperature-controlled ventilated embankment in Qinghai-Tibet testing expressway

Abstract

Temperature-controlled ventilated embankment (TCVE) is a feasible air-cooled embankment. It can control the heat transfer mode in ventilated duct of duct ventilated embankment according to the ambient air temperature with auto-temperature-controlled wind doors installed in the duct nozzle. For investigating the cooling performance and engineering effect of TCVE, a prototype testing section of the expressway was constructed on Qinghai-Tibet Plateau. The field observation data showed that the mean air temperature inside the duct in the warm season after installing the doors was about 3 °C lower than the temperature before installing the doors. The annual net heat release was 1.4 times than that before installing the doors near the permafrost table. One year after installing the doors, the 0 °C isotherm was raised by approximately 0.5 m and kept parallel to the embankment base; and a low-temperature zone of −2 °C appeared, and the zone below −1.5 °C was approximately 1.3 times than that before installing the doors. With the cooling effect of TCVE, the trend of embankment settlement was retarded, and the frost-heave capacity showed a tendency to decrease. This study verified the effectiveness of TCVE, which has a potential in cooling embankments in expressway construction in permafrost regions.