表面条件对透壁通风管碎石路堤降温效果的影响

针对青藏高原冻土区高速公路拟采用的透壁通风管碎石路堤，进行了表面开放和封闭透壁通风管碎石试样降温效果的室内试验，分析比较了表面开放和封闭边界条件对透壁通风管负温通风增强碎石路堤降温效果的影响差异。分析表明，表面开放和封闭透壁通风管碎石路堤都以外界空气通过管壁透气小孔与通风管附近碎石区域孔隙空气循环产生的强迫对流传热增强降温作用，另外，表面封闭透壁通风管碎石路堤能够在上部碎石区域产生孔隙空气循环的自然对流降温效应。因此，表面封闭透壁通风管碎石路堤的降温效果更为显著。

Impact of top boundaries on cooling effect of crushed rock embankment embedded a perforated ventilation pipe

Crushed rock embankments embedded a perforated ventilation pipe are employed in the expressway construction of the Qinghai-Tibet Plateau. Laboratory experiments for the cooling effect in crushed rock embankment samples with air-open/air-tight surfaces embedded a perforated ventilation pipe are performed. Impacts of air-open/air-tight top boundaries on the cooling effect in crushed rock embankment embedded a perforated ventilation pipe are analyzed. The analysis shows that the air-open/air-tight crushed rock embankments embedded a perforated ventilation pipe can enhance the cooling capability of the embankment base due to forced convective heat transfer of the pore air motion in the crushed rock region near the ventilation pipe forming a pore air circulation in conjunction with the ambient air by the small holes of ventilation pipe wall, and the natural convective cooling effect due to pore air circulation may occur in the upper region of the crushed rock embankment during the negative air temperature ventilating period. Hence, the cooling effect in the air-tight crushed rock embankment embedded a perforated ventilation pipe is significant due to ventilating during the negative air temperature fluctuation period.