塔克拉玛干沙漠沙垄区公路防护带内风场特征研究

塔克拉玛干沙漠公路是世界上穿越流沙区最长的公路,公路两侧防沙治沙工程体系是公路正常运行的关键因素。以塔克拉玛干沙漠沙垄区的公路防护林带为研究对象,结合野外地形测量、防护工程调查以及风沙数据观测,分析沙垄不同地貌部位防护林带内气流特征,揭示防护林带内风场变化规律,探讨不同地貌部位防护林带的防护效果。主要结论是:①垂直于公路的防护林带断面风场存在3个区(防护林带前部风速迅速降低区、防护林带中部风速低值区、防护林带工程后部风速恢复区),气流穿过公路路面时风速呈增大趋势,利于公路防护;②现有防护林带具有较好的防护效果,相对于防护林带上风向流沙区的风速,防护林带中部风速降低幅度在80%以上,多数断面在林带前缘10H后（H为植株平均高度）风速降低至最小;③沙垄不同地貌部位的工程防护效益存在显著差异,迎风坡底部防护效果最好,迎风坡中部防护最差。其研究结果可为塔克拉玛干沙漠公路防沙治沙工程体系优化提供科学依据。

Wind Speed Change within the Shelter Forest along the Taklimakan Desert Highway

The Taklimakan Desert Highway is the longest highway crossing a drift sand region in the world. The blown sand prevention and control engineering system is a key factor determining whether the highway can operate smoothly. Based on topography measurement, engineering measurement survey and air flow field observation within the shelter forest along the Taklimakan Desert Highway in the dune area, this paper studied the characteristics of wind speed change at different sand dune positions within the shelter forest, and analyzed the blown sand prevention and control efficiency of the shelter forest. Main results include: (1) There are three regions for the wind velocity change within the shelter forest along the section perpendicular to the road: area of wind velocity quickly reducing in front of the shelter forest, area of minimum wind velocity in the middle of the shelter forest, and area of wind velocity respeeding up behind shelter forest. The increasing tendency of wind velocity on the road surface would help to protect the highway from sand disaster. (2) The shelter forest is efficient in preventing sand disaster with more than 80% reduction of wind velocity in the middle of the shelter forest compared to the wind velocity in front of the shelter forest. Wind velocity can be reduced to the minimum when the distance from the edge of the shelter forest surpasses the distance of 10 times height of the forest. (3) There is a notable difference in protective efficiency of the shelter forest at different geomorphologic positions, and the best protective efficiency is present at the bottom of windward slope of sand dunes, the worst at the middle position of the windward slop of sand dunes.