植被覆盖度与空间格局对坡面流水动力学特性的影响

发布时间：2019-01-27 19:02

【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。
[Abstract]:In order to study the effect of vegetation coverage and spatial pattern on hydrodynamic parameters of slope surface, four types of vegetation cover and three spatial patterns of vegetation in 5 slopes were quantitatively studied by means of indoor fixed bed scour test and cylindrical simulation of trees. The influence of vegetation coverage and spatial pattern on the hydrodynamic parameters of slope surface was discussed, and the influence index of vegetation coverage and spatial pattern on flow velocity and resistance was analyzed. The results show that the variation range of flow velocity is between 0.2~1.4m/s and the minimum velocity is the slope condition with the coverage of 6.1% angle scale 0, and the largest one is the bare slope (control). The variation of flow exponent of each slope condition is 0.7 ~ 0.8, which indicates that the main work of water flow is to overcome the resistance. The effect of coverage on velocity is greater than that of spatial pattern under each discharge, and the effect of spatial pattern is only 50% of coverage. The resistance coefficient of slope increases with the increase of coverage. Under each slope, Darcy resistance coefficient varies from 0 to 0.16, and the resistance coefficient at angle scale is larger than that at other angle scales. The effect of coverage on the resistance coefficient of slope flow is greater than that of spatial pattern. In the gentle slope (below 10 掳), the effect of spatial pattern on the flow resistance of slope is more than 50% of the effect of coverage on the resistance of slope flow. However, the effect of spatial pattern on the flow resistance of steep slope (above 15 掳) is only about 20% of that of coverage.
【作者单位】：北京林业大学水土保持与荒漠化防治教育部重点实验室;
【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)
【分类号】：S157.43

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