为了探明沙面粗糙元覆盖物的几何外形对地表风沙活动的抑制作用关系,用球形、三棱锥形、圆柱形、正方体形、饼形和半球形6种外形的粗糙元(自制,保持单颗粒等质量)覆盖(盖度10%)流沙面,分别在净风和挟沙风条件下进行风洞模拟实验。结果表明:①净风条件下,球形、三棱锥形、圆柱形和正方体形粗糙元覆盖床面的风蚀量明显小于饼形和半球形覆盖床面,正方体形、圆柱形、三棱锥形和球形的抗风蚀效率也较饼形和半球形好;②挟沙风条件下,随着风速的增加,球形、三棱锥形、圆柱形覆盖沙面由风积向风蚀转化,风蚀量随风速增大而增大,当风速大于10 m/s,床面均表现为强烈侵蚀,其中饼形和半球形阻沙功能较弱,两者风蚀率最大;③无论是净风,还是挟沙风条件,床面风蚀量均受粗糙元的方向比率、高度和间距等因素的影响,相同覆盖度下,细高、有明显边界的粗糙元防护效果好于粗矮的粗糙元。

In order to study the relationship between the shapes of roughness-elements on sand beds and the surface sand activity inhibition, we chose six shapes of elements including spherical, triangular pyramid shape, cylindrical, square shape, pie and hemispherical shape by hand with equal quality kept. We carried out the experiment with the 10% coverage on the wind tunnel. The results revealed that ① the erosion and anti-erosion rate of spherical, triangular pyramid shape, cylindrical and square roughness-elements were better than the pie and hemispherical on the non-sand wind; ② On the sand-driving wind conditions, spherical, triangular, cylindrical covered beds became erosion to erosion-deposition with the increase of wind speed, and the erosion rate was increased with the wind speed. When the wind speed was more than 10 m/s, the sand-beds showed a strong erosion, and the pie and hemispherical elements’ resistance function were weakest; ③ No matter the non-sand wind or sand wind, the erosion rate was affected by the elements’ aspect ratio, height and spacing. The slender elements with a prominent upper edge were clearly superior to broad rounded elements.