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利用高精度微风速探测仪,通过室内模型试验首次获得了在大孔隙空心块石层内由温差引起的空气流速,并对空心块石层内的对流过程、降温过程及其相互关系进行了详细分析,而后结合实体工程分析了该措施的降温效能及优越性。结果表明:空心块石层降温效能突出且降温迅速,放热时间和吸热时间基本相当;空心块石层中对流速度显著,高达0.12 m.s-1,受到温度差异影响,在稳定区前后对流速度存在差异,最大相差0.023 m.s-1;温差是自然对流的驱动力,自然对流引起降温过程;不同传热方式及强度引起温度非对称性变化;对流速度和温差具有线性相关性,对流的发生存在起始温差;通过实体工程证实,空心块石层的降温效能相当突出,在1年中原冻土上限附近降温幅度达到0.3℃,路基内降温深度达到10 m。
The air velocity caused by temperature difference in the macroporous hollow block rock mass was obtained by the indoor model test for the first time by using a high-precision micro-wind velocity detector. The convection process, cooling process and their correlation in the hollow block rock mass were described in detail Analysis, and then combined with the physical engineering analysis of the measures of cooling efficiency and superiority. The results show that the cooling performance of hollow block stone is prominent and the cooling time is rapid, and the exothermic time and endothermic time are basically the same. The convective velocity of hollow block stone is significant, reaching as high as 0.12 ms-1. Under the influence of temperature difference, The maximum difference is 0.023 ms-1. The temperature difference is the driving force of natural convection, and the natural convection causes the cooling process. The different heat transfer modes and intensities cause the asymmetry of temperature. The convection velocity has a linear correlation with the temperature difference and convection occurs Initial temperature difference. It is confirmed by physical engineering that the cooling performance of the hollow block stone layer is outstanding. The temperature drop range of the frozen soil near the upper limit of the frozen soil reaches 0.3 ° C in 1 year and 10 m in the subgrade.