青藏高原公路路基周边风场特征风洞实验研究

路基高度是影响冻土路基工程热力稳定性的一个重要指标。同时，不同高度的路基对其周边风场的扰动也将不同，进而影响到局地的地-气能量交换过程。为揭示不同高度路基对其周边风场特征的影响规律及程度，基于风洞实验，研究了3种环境风速条件下青藏高原典型高度公路路基周边风场分布特征，并进行了量化分区。结果表明：路基坡前为流场减速区，不同高度情况下路基坡前减速区水平范围差异显著。10 m·s^-1环境风速条件下，3、4和5 m高路基坡前减速区水平范围约为1.8、2.2和2.5倍路基高度（H）。在路基坡前减速区0.3~1.1 m高度范围内，随环境风速增加，同一水平高度流场在靠近路基过程中风速的变化率呈下降趋势。路基上部为流场加速区，路肩处风速增长幅度与路基高度呈正相关。路基坡后为低速回流区，路基高度越大，低速回流区水平范围越大，10 m·s^-1环境风速条件下，3、4和5 m高度路基坡后低速回流区水平范围分别约为2.0H、3.0H和4.1H。低速回流区后，流场逐渐恢复到初始运动状态，其消散恢复区水平范围与环境风速密切相关，但与路基高度关系不显著，10 m·s^-1环境风速条件下，3、4和5 m高度路基坡后消散恢复区水平范围均约为9.8H。通过考虑路基高度对其周边风场分布的影响，可为块石、通风管、热管等冻土路基结构的设计和布局优化提供参考。

Wind tunnel test on wind flow around highway embankment on the Qinghai-Tibet Plateau

The hight is an important factor for the long-term thermo-mechanical stability of highway embankment in permafrost zones. Moreover， the embankment with different hights will exert different impacts on the wind flow around it， which would furtherly affect the ground-air energy exchange process. In order to reveal the influence of embankment height on the wind flow around the embankment， the distribution characteristics of wind flow around highway embankment with different heights were investigated with three ambient wind speeds by the wind tunnel test. The results showed that the front of embankment was a deceleration zone of wind flow， and the range of the zone was close related to the embankment hight. When the ambient wind speed was 10 m·s^-1， the deceleration zones of the embankment with the heights of 3， 4 and 5 m were 1.8， 2.2 and 2.5 times of the embankment hight （H）， respectively. Within the heights from 0.3 to 1.1 m before the windward side of embankment， the change rate of the wind speed decreased with the increasing ambient wind speed when the flow field got close to the embankment. The upper part of the embankment was the acceleration zone of wind flow， and the increase of the wind speed on the embankment shoulder was positively correlated with the height. There was a reflux zone with low wind speed at the leeward side of the embankment. The greater the embankment hight was， the wider the reflux zone would be. When the ambient wind speed was 10 m·s^-1， the horizontal range of the reflux zone was 2.0H， 3.0H and 4.1H corresponding to the embankment hights of 3， 4 and 5 m， respectively. When the wind flow away from the leeward side of embankment， the wind flow recovered gradually to the natural conditions. The horizontal range of the recovery zone of the wind flow was closely related to the ambient wind speed， but had no significant relationship with the embankment hight. The horizontal range of the recovery zone of the wind flow was approximately 9.8H when the ambient wind speed was 10 m·s^-1. The study could provide informative reference for the design and construction of embankment equipped with the air-cooled structures， including the crushed rock layers， ventilation ducts and thermosyphons.