摘要
为研究植被覆盖度与空间格局对坡面流水动力学参数的影响,采用室内定床冲刷试验,以圆柱体模拟树木定量研究了4种覆盖度、3种空间格局的植被在5个坡度、6个流量下坡面薄层流水力要素及阻力的变化特征,探讨了植被覆盖度、空间格局对坡面流水动力参数的影响,并分析了植被覆盖度和空间格局对流速和阻力的影响指数。结果表明,在5种坡度下流速的变化范围在0.2~1.4m/s之间,流速最小的是覆盖度为6.1%角尺度为0的坡面条件,最大的是裸坡（对照）。各坡面条件的流态指数变化在0.7~0.8,表明水流以克服阻力做功为主。覆盖度对流速的影响在各流量下皆大于空间格局对流速的影响,且空间格局的影响效果只有覆盖度的50%。坡面阻力系数随着覆盖度的增加而增加,在各坡度下,达西阻力系数在0~0.16间变化,角尺度为0时的阻力系数大于其它角尺度下的。覆盖度对坡面流阻力系数的影响大于空间格局对阻力系数的影响。在缓坡（10°以下）,空间格局对坡面流阻力的影响是覆盖度对坡面流阻力影响的50%以上,而在陡坡（15°以上）空间格局对坡面流阻力的影响仅仅是覆盖度对坡面流阻力影响的20%左右。
To study the influence of vegetation coverage and spatial distribution pattern on overland flow hydrodynamic characteristics,the indoor fixed bed scouring experiment was carried out to quantitatively discuss the variation characteristics of hydraulic parameters and resistance of overland flow at 4vegetation coverage degrees and 3types of spatial distribution pattern,and under 5slope gradients and 6flow discharges,and explore the effect of vegetation coverage and spatial distribution pattern on hydrodynamic characteristics of overland flow,as well as on the flow velocity and resistance.The results showed that the velocity varied from 0.2m/s to 1.4m/s and the slope of 0degree and 6.1%vegetation coverage had minimum velocity while the bare slope had maximum velocity on all slope gradients.Flow-state indicators changed from 0.7to 0.8,implying that main energy consumption was to overcome resistance.The change of velocity caused by vegetation coverage was larger than that caused by spatial distribution pattern,and the influence caused by spatial distribution pattern was half as large as that caused by vegetation coverage.The slope resistance coefficient which varied from 0to 0.16 was increasing with the increase of vegetation coverage.When the slope degree is 0,the velocity was the largest.The change of resistance coefficient caused by vegetation coverage was larger than that caused by spatial distribution pattern.The change of overland flow resistance coefficient caused by spatial distribution pattern was 50% higher than that caused by vegetation coverage when the slope gradient was small（≤10°）.However,The change of overland flow resistance coefficient caused by spatial distribution pattern was about 20% of that caused by vegetation coverage when the slope was steep（15°）.
出处
《水土保持学报》
CSCD
北大核心
2016年第2期26-33,共8页
Journal of Soil and Water Conservation
基金
国家自然科学基金项目(51309006)
高等学校博士学科点专项科研基金项目(20130014120022)
关键词
坡面流
覆盖度
空间格局
流速
水动力学参数
影响指数
overland flow
vegetation coverage
spatial distribution pattern
velocity
hydrodynamic characteristic
impact factor
