沙袋沙障对沙丘表层粒径影响的研究

Effect of Sandbag Barrier on Surface Particle Size of Sand Dunes

PLA纤维是一种新兴固沙材料,用它灌沙形成的筒状沙袋铺设于沙丘上形成沙障,可以改变近地表风沙流结构和地表粗糙度等因子。为了解该PLA沙障对沙丘地表土壤粒径的影响情况,在铺设沙障沙丘及对照沙丘分别取0～11 cm土样,用Rise-2008型激光粒度分析仪测定土样平均粒径,对比研究不同规格、不同部位PLA沙障与对照沙丘表层平均粒径的差异。结果表明:1 m×1 m、2 m×2 m、3 m×3 m PLA沙障3种规格相比,规格越大其平均粒径反而越小,但是均显著高于对照沙丘(P<0.005);铺设沙障沙丘的迎风坡、坡顶和背风坡平均粒径分别比对照沙丘高11.4%、26.8%和1.8%;并且坡顶平均粒径最大,迎风坡次之,背风坡最小,对照出现相同的变化趋势。

As a new kind of sand - fixing material, PLA fiber is used to form sandbag barrier by filling with sand and setting these cylindrical sandbags on the sand dunes, which can change the near- surface sand flow structure, surface roughness and other factors effectively. In order to understand the influence of PLA sand barrier on surface particle size of sand dunes, soil samples from 0 to 11 cm have been taken in dunes laid with sand barriers and the control dune, and the average particle size has been measured with Rise -2008 laser particle size analyser for con- trasting the difference of average particle size between PLA sand barrier in different specification and position and the control dune. The results show that comparing the PLA sand barriers in 1 m ~ 1 m, 2 m ~ 2 m and 3 m x 3 m, the smaller the average particle size is, the higher the specification of PLA sand barrier is, which is bigger than the control dune obviously （ p 〈 0.005 ）. The averge particle size in windward slope, slope top and leeward slop laid sand barriers are 11.4%, 26.8% and 1.8% higher than the control dune seperately. The average particle size in slope top is the highest, the one in windward slope is the second and the one in leeward slope is the lowest, which the trend is consistent with the control.