青藏高等级公路通风管试验路基降温效果

在假定未来50a气温升高2.6℃和初始年平均气温为-4.0℃的前提下,应用有限体积法(FVM)对青藏高等级公路试验示范工程段普通路基、普通通风管路基和通风管-XPS复合路基温度场进行三维非线性分析.结果表明,普通路基下部冻土退化严重,第50年的最大融化深度为10.98m,冬季土体中有融化核存在.普通通风管路基和通风管-XPS复合路基在一定时期内可以降低下部多年冻土的温度,提高0℃等温线,且通风管-XPS复合路基的降温效果略优于普通通风管路基,但在气温不断升高和沥青路面吸热的双重影响下,这2种路基的坡脚处会出现融化核,且0℃等温线已经延伸到路基中心处,这将直接影响路基的稳定性.

Cooling effect of ventilated experimental embankment of Qinghai-Tibet high-grade road

Assuming the total rising temperature of 2.6 ℃ in next 50 years and the initial mean annual air temperature of -4.0 ℃, the three-dimensional temperature fields of the traditional embankment, the ordinary duct ventilated embankment and the duct ventilated XPS embankment were analyzed by the finite volume method (FVM). Results show that the permafrost underlying traditional embankment is seriously degraded and the thaw depth is 10.98 m at the 50th year, meanwhile there is a thaw bulb in the soil in the winter. Both the ordinary duct ventilated embankment and the duct ventilated XPS embankment can cool down the permafrost and uplift the 0 ℃ isotherm beneath the embankments. The cooling effect of the duct ventilated XPS embankment is slightly better than that of the ordinary duct ventilated embankment, but the thaw bulbs will appear under the slope toes due to the climate warming and the heat absorption of asphalt pavement, and the 0 ℃ isotherm is extended to the center of embankment, which will affect the thermal stability of embankment.