河岸边坡草被减流减沙效应及其坡面流水动力学特征  

Effects of Grass Coverage on Runoff and Sediment Reduction and the Hydrodynamic Characteristics of Slope Runoff on River Bank Slope

作　　者：王志刚[1] 杨海龙[1] 刘慧博[1] 张嫱[1] 涂剑[1] 

机构地区：[1]北京林业大学水土保持与荒漠化防治教育部重点实验室,北京100083

出　　处：《水土保持学报》2016年第2期8-13,共6页Journal of Soil and Water Conservation

基　　金：国家林业公益性行业科研专项"建设工程损毁林地植被修复关键技术研究与示范"(200904030)

摘　　要：为研究草本植被覆盖对河岸边坡坡面流水动力学特征及产流产沙规律的影响,阐明坡面生物措施的减流减沙效益,在放水流量为5ml/s、坡度约为15°的条件下对不同草本植被覆盖类型的河岸自然边坡进行野外放水冲刷试验。结果表明:(1)植被覆盖坡面的初始产沙量均大于裸地,黄花蒿的产沙量最大(1.92g),其次是野豌豆(1.73g)、狼尾草(1.24g),裸地(0.96g)最小;从产沙趋势上看,裸地坡面的产沙过程呈先升高后下降的趋势,而狼尾草、野豌豆、黄花蒿则呈整体递减趋势;(2)4种不同下垫面边坡土壤稳定入渗率介于2.10~4.30之间,狼尾草(4.30mm/min)最大,野豌豆(3.91mm/min)、黄花蒿(3.10mm/min)次之,裸地(2.10mm/min)最小,且入渗过程均符合Horton入渗公式:i=i_c+(i_0+i_c)e^(-kt);(3)各草本植被覆盖坡面的减流效益按大小排序为狼尾草(57.41%)>野豌豆(40.74%)>黄花蒿(37.03%);减沙效益大小排序为狼尾草(55.73%)>野豌豆(45.71%)>黄花蒿(26.89%);(4)3种草本植被坡面的径流流速及费汝德数均小于裸地,而雷诺数与裸地相比差异不大,均分布在32.46~33.90之间;各植被坡面的Darcy—Weisbach阻力系数及糙率系数分别是裸地的3.96~12.85倍和1.96~2.52倍。研究结果可为进一步揭示草被的减流减沙作用及土壤侵蚀动力过程提供理论依据。In order to study the influence of grass coverage on hydrodynamic characteristics of overland flow and the law of runoff and sediment generation on the river bank slope,illuminate the runoff and sediment reduction effect of biological measures,the runoff and scouring experiment was conducted on the natural slope of river bank,covered by different types of herbaceous vegetation,under the condition of 5ml/s scouring flow rate and 15 degrees of these slopes.The results showed that：（1）The initial sediment yield of slope covered by vegetation was greater than that of bare land.Slope covered with Artemisia annua Linn.produced about1.92 g sediment in the first 2minutes,followed by slope with Vicia sepium Linn.（1.73g）and Pennisetum alopecuroides（L.）Spreng.（1.24g）,and bare land（0.96g）.The curve of sediment transporting on the control slope showed high-low trend,while it was constantly decreasing on the vegetation slopes.（2）The values of soil stable infiltration rate ranged from 2.10 to 4.30 mm/min on these 4different slopes,which were 4.30 mm/min,3.91 mm/min,3.10 mm/min and 2.10 mm/min on slope with Pennisetum alopecuroides（L.）Spreng.,Vicia sepium Linn.,Artemisia annua Linn.,and on bare land,respectively.The process of water infiltration was coincided with Horton formula：i=ic＋（i0＋ic）e^（-kt）.（3）The descending order of runoff reduction effect of 3herbaceous vegetation was as follows：Pennisetum alopecuroides（L.）Spreng.Slope（57.41%）〉Vicia sepium Linn.Slope（40.74%）〉Artemisia annua Linn.（37.03%）,and the sediment reduction effect followed the order：Pennisetum alopecuroides（L.）Spreng.Slope（55.73%）〉Vicia sepium Linn.slope（45.71%）〉Artemisia annua Linn.（26.89%）.（4）The runoff velocity and Froude number of vegetation slopes were both less than those of the control group,while the Reynolds number did not differsignificantly,ranging from 32.46 to 33.90.The Darcy- Weisbach resistance coefficient and roughness coefficient of the vegetation slop

关 键 词：河岸边坡 减流减沙 水动力学特征 冲刷试验 

分 类 号：S157.1[农业科学—土壤学]