为探究 3 种典型机械防沙工程措施实施后所体现的防护效益,通过风洞模拟试验,以敦煌黑山嘴地区的典型机械防沙工程为参考,对草方格与尼龙网格状沙障及阻沙栅栏的防风、固阻沙效益进行系统的对比分析.结果表明:草方格与尼龙网格状沙障的布设均能有效降低风速,当指示风速为 20 m/s 时,1.5 cm高度的风速降低率分别达到 82.5%与 80.9%,同时极大地增加流沙地表粗糙度,显著影响当地的风速变化;此外,两者在不同高度对风速削弱能力差异明显;草方格与尼龙网格状沙障也深刻影响当地风沙流结构,其中草方格沙障的固沙能力主要体现在近地表;阻沙栅栏前后平均输沙率降低 44.2%,同时对当地流场结构影响深刻.综合分析可知,草方格与尼龙网格状沙障防风、固沙效益良好,阻沙栅栏阻沙效益显著.研究结果可为当地机械防沙工程建设提供指导,同时对其他地区防沙工程布设予以借鉴.
Comparative Analysis of Protective Benefits of Typical Mechanical Sand Control Projects Based on Wind Tunnel Simulation Experiment
In order to explore the protection benefits of three typical mechanical sand control engineering measures after implementation,through wind tunnel simulation experiments,taking the typical mechanical sand control engineering in Heishanzui area of Dunhuang as a reference,the wind and solid sand resistance benefits of grass grid and nylon grid sand barrier and sand-blocking fence were systematically compared and analyzed.The results show that both grass grid and nylon grid sand barrier can effectively reduce the wind speed,when the indicate wind speed is 20 m/s,the wind reduction rates at 1.5 cm height reach 82.5%and 80.9%,meanwhile,the surface roughness of quicksand is greatly increased,which significantly affects the local wind speed.In addition,these two sand barriers have obvious differences in the ability to waken the wind speed in different heights.The grass grid and nylon grid sand barrier also have significant influence on the local wind-sand flow structure,the sand-fixing ability of grass grid sand barriers is mainly reflected in the near surface.The average sediment transport rate before and after the sand barrier is reduced by 44.2%,and it has a profound impact on the local flow field structure.Comprehensive analysis shows that the grass grid and nylon grid sand barrier have good windproof and sand-fixing benefits,and the sand-blocking fence has significant sand-blocking benefits.The research results can provide guidance for the construction of local mechanical sand control projects,and provide reference for the layout of sand control projects in other areas.