多边形草沙障防风效果研究

为了解正三角形、正方形和正六边形格状草沙障的防风固沙能力，通过测定沙障样地内不同高度风速，针对单个网格面积为1 m2的3种沙障，对沙障的防风效能、风速廓线特征和地表粗糙度进行研究。结果表明，正三角形和正六边形沙障的防风效能显著大于正方形沙障。高度为0.2 m时，正方形沙障的防风效能比三角形和六边形沙障分别低12%和8%，高度为0.3 m时，分别低11%和10%。0.2~0.3 m高度范围内，三角形沙障和六边形沙障的防风效能差异不显著。风速小于6 m/s时，地表粗糙度随风速变化接近线性变化规律。裸露地表 1 m高处，风速为4 m/s时，裸露地表粗糙度为0.166 cm，三角形沙障、正方形沙障和六边形沙障的地表粗糙度分别为11.5、9.3和10.4 cm，分别为裸露地表粗糙度的69.3、56和62.7倍。三角形沙障的地表粗糙度比正方形沙障和六边形沙障的地表粗糙度分别高23.7%和10.5%。铺设三角形沙障的地表粗糙度最大。 

Research on the windproof efficiency of polygonal straw sand barrier

To understand the windproof benefit of triangular sand barrier, square sand barrier and hexagonal sand barrier, we studied respectively the windproof efficiency, wind speed profile characteristics and roughness of ground surface of straw sand barrier, whose single mesh grid was 1 m2 by measuring the wind speeds in different heights in three straw sand barrier types. Results showed that wind speed efficiency could be reduced by triangular sand barrier and hexagonal sand barrier significantly than square sand barrier. The windproof efficiency of square sand barrier was 12％ and 8％ lower than triangular sand barrier and hexagonal sand barrier respectively at 0. 2 m height, and was 11％ and 10％ lower than triangular sand barrier and hexagonal sand barrier respectively at 0. 3 m height. The difference of windproof efficiency in triangular and hexagonal sand barrier was not obvious at he height between 0. 2-0. 3 m. The variation of roughness with wind speed was linear when the wind speed was less than 6 m/s. When wind speed was 4 m/s at 1 m height above bare sand, the roughness of bare sand was 0. 166 cm, and the roughness of triangular sand barrier, square sand barrier and hexagonal sand barrier was 11. 5, 9. 3 and 10. 4 cm, respectively, and was 69. 3, 56 and 62. 7 times of bare sand. The roughness of triangular sand barrier was 23. 7％ and 10. 5％ higher than that of square sand barrier and hexagonal sand barrier, respectively. Consequently, the roughness of triangular straw sand barrier is the highest.