中文摘要：

利用块石层调控路基地温是冻土工程主动冷却路基的一种重要措施,有关块石层的降温性能和对流换热过程是冻土工程应用研究的重要内容之一。试验基于块石层的对流换热机理以及影响块石降温性能和对流过程的因素,提出一种新型的空心块石路基结构,通过室内模型试验对空心块石层的对流过程、温度特性及降温影响因素进行研究,并通过高精度微风速探测,首次获得封闭条件下空心块石层的对流特征和温度特性的关系,实测证实对流换热过程的存在。研究发现,换热过程和换热强度的差异导致温度曲线的非对称性,对流换热是空心块石层降温的根本原因;空心块石层上下表面温差和对流速度大小存在一定的联系,对流速度和对流时间的长短直接影响降温效果;空心块石层降温效果相当显著,并且垂直堆放方式和大尺寸空心块因具有较畅通的对流通道,降温速度更快且效率高,对流放热时间明显延长。该试验研究成果将对该种新型工程措施机理的进一步认识和改进,以及在冻土区高速公路等重大工程建设中的应用都具有指导意义。

英文摘要：

Active cooling roadbed employed brick-stone layer in permafrost regions is an important engineering measure,it is one of the important elements of application research of frozen soil engineering to study cooling effect and heat convection process in block-stone layer.Based on convection heat transfer mechanism,influence factors of cooling effect and heat convection process,a new hollow concrete brick embankment is suggested for Qinghai-Tibet Expressway.The heat convection process,temperature characteristic and influence factors of cooling effect in hollow concrete brick layer are studied in detail by means of model experiment in lab,and employed high-precision macro wind-speed detector,the relationship between the natural convection and temperature characteristics are got for the first time,and existence of convection heat transfer is confirmed.Research results indicate that the asymmetry of temperature fluctuation result from different heat transfer process and intensity,the reason of cooling effect is convection heat transfer;the temperature difference is driving force of natural convection,duration and strength of which influence directly the cooling effect of the hollow concrete brick layer;the cooling effect of the hollow concrete brick is superior,and the vertical stacking and large size with smooth convective channels are better choices,which will extend obviously heat convection time.The experimental research results have a great guide significance for further understanding of cooling mechanism,improvement of this measure,as well as for effective application of Qinghai-Tibet Expressway in permafrost regions.