摘要
位于干旱区的甘肃省民勤县水资源缺乏,沙障为该地区防风固沙的措施之一,对于区域风沙灾害防治具有重要意义。在流动的新月形沙丘迎风坡设置塑料网方格沙障,观测沙丘迎风坡下部、中部和上部的沙障内不同高度风速、输沙量、沙面形态变化和风蚀深度以及沙障破损量。分析结果表明:设置塑料网方格沙障降低了风速,沙丘下部是沙障内同一高度的风速降低幅度最大部位;在沙障内,高度20cm以下的风速为对照的75%以下;风蚀深度和积沙量最大的部位也是沙丘下部。沙障内风速随高度变化呈对数分布,40cm高度处为风速变化拐点;沙丘中部和上部的风速相对沙丘下部的较大,沙丘中上部的风速为沙丘下部的1.18～2.01倍。在沙障内,10～20cm高度范围的输沙率较大,在沙丘下部占总输沙率的60.57%,沙丘中部占69.11%,而沙丘上部则达91.20%。沙障内的沙面稳定后形成了凹曲面,但形成过程与麦草方格沙障不同。塑料网方格沙障是一种积沙型沙障。沙丘中上部的沙障破损率相对较大,在设置沙障时应注意加强。
The sand barrier is one of methods to break wind and control sand,because the environment is harsh in arid area with less water resource.The plastic checkerboard sand-barrier was set on the leeward of crescentic dune,and some index,such as wind velocity,transported quantity of sand,shape of surface of sand-land,depth of erosion and breakage ratio of sand barrier were observed.The results showed that：The wind velocity was decreased when the plastic checkerboard sand-barrier was set on the leeward of crescentic dune.The wind velocity decreased 75% than that of CK at height of 20 cm above the barrier at the bottom of leeward of dune,which was the decreased maximal number that were observed and compared with the decreased number of wind velocity at the position,such as the bottom,middle and upper of leeward of dune,as well as the aeolian depth and deposition of sand.The function was logarithmic equation between wind velocity and height,and the height of 40 cm was an inflection point where wind velocity changed significantly.The wind velocity at bottom was less than that of middle and upper of dune leeward,and the wind velocity of middle and upper of dune was 1.18~2.01 times comparing with that of bottom of dune.The height,where the transported quantity of sand was maximum,was 10~20 cm,and the ratio of sand volume was 60.57% at the observed time at the bottom of dune,as well as 69.11% and 91.20% at middle and upper of dune leeward.A concave profile was formed in the plastic checkerboard barrier when the sandy surface was stable,but the forming process was deferent comparing with the forming process of concave profile of straw checkerboard barrier.The plastic checkerboard barrier was an accumulating barrier.The broken ratio of barrier was much larger than that of middle and upper of dune leeward.It was attention that the plastic checkerboard barrier was set at the middle and upper of dune leeward.
出处
《水土保持学报》
CSCD
北大核心
2011年第5期26-29,34,共5页
Journal of Soil and Water Conservation
基金
甘肃省自然科学基金项目(3ZSO41-A25-015)
甘肃省科技重大专项(1002FKDA040)
关键词
塑料网方格沙障
新月形沙丘迎风坡
风沙流
plastic checkerboard barrier
leeward of crescentic dune
wind-sand flux
作者简介
刘虎俊（1965--），男，甘肃礼县人，博士研究生，研究员，主要从事风沙工程和荒漠生态研究。E—mail：liuhujun66@sina.com
通讯作者：马瑞（1977--），女，甘肃平凉人，博士，助教，主要从事水土保持与荒漠生态教学与研究。E-mail：marui770625@126.com
