| 坡面侵蚀过程中细沟水流动力学参数估算探讨 |
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| 引用本文： | 张科利,张竹梅.坡面侵蚀过程中细沟水流动力学参数估算探讨[J].地理科学,2000,20(4):326-330. |
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| 作者姓名： | 张科利 张竹梅 |
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| 作者单位： | 1. 北京师范大学资源与环境科学系，北京 100875
2. 北京师范大学天文系，北京 100875 |
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| 基金项目： | 国家自然科学基金重点项目!(19832 0 6 0 )，国家杰出青年科学基金!(4 972 5 10 3)，国家重点基础研究发展规划项目!(G19990 436 0 5 |
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| 摘 要： | 细沟侵蚀是坡面侵蚀的主要方式 ,在坡面侵蚀产沙及其输移过程中占有重要的地位和作用。通过放水冲刷试验 ,测定并研究了坡面细沟中径流的水力要素特征及其相互关系。试验中坡度采用 6° ,10°,12°和 15°共 4级 ,径流流量变化控制在 40～ 5 0 0ml/s之间。结果表明 ,黄土陡坡上细沟径流的流速、过水断面宽度 ,以及径流深都能表示成径流量和坡度的函数。在确定坡面细沟流各水力要素间关系指数的基础上 ,探讨了用径流量和坡度因子估算细沟径流水力参数的方法。经用实测资料验证 ,在实验土壤及流量、坡度条件下 ,用文中提出的方法估算的细沟径流深具有一定的精度。
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| 关 键 词： | 黄土坡面 细沟 水力特征 侵蚀预报 水流动力学 |
| 文章编号： | 1000-0690(2000)04-0326-05 |
Prediction of Hydraulics of Rills in Erosion Processes on Hillslope |
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| ZHANG Ke-li,ZHANG Zhu-mei.Prediction of Hydraulics of Rills in Erosion Processes on Hillslope[J].Scientia Geographica Sinica,2000,20(4):326-330. |
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| Authors: | ZHANG Ke-li ZHANG Zhu-mei |
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| Abstract: | Soil erosion has been a worldwide environmental problem. Soil erosion results in not only degenerationof soil productivity, but also floods and pollution of water resources. Soil erosion and its controls have been stud-ied extensively. A major field of these is the soil loss prediction which enables the planner to predict the averagerate of soil erosion. With the development of computer technology, soil erosion prediction has shifted from em-pirical models to theoretical models. But it is difficult to measure the hydraulics needed in construction of pro-cess-based model. In this study, inflow experiments were conducted on the loess slope to determine hydrody-namic characteristics of flow in rills, and friction coefficients on the steep slope conditions.
All experiments were conducted in a 5-m-long, 0.5-m-wide, and 0.7-m-deep flume. Slope steepness can be manu-ally adjusted to 6°, 10°, 12°, 15° and 20°. To let water infiltrate tested soil freely, natural sands was packed into theflume about 0.3 m in depth before soil was filled in, and than tested soil was filled and adjusted to reach a bulk density of1.17 g/cm3. Inflow water was added from the top end of the flume and inflow volumes, controlled with a watergauge,were designed as 40, 60, 100, 200, 300 and 500 rnl/s respectively. Throughout each run the following data were col-lected: mean velocity, depth of runoff, section shape of rill, and sediment samples. Each run consisted in 30 - min dura-tion and two replications of each of five slopes were assigned.
Experiments results show that hydraulic geometry of rill on the loess slope, which are the mean width ofcross-sections, mean velocity, mean depth of flow, could be related to discharges and slope gradient in power re-lations. Manning roughness coefficient ranges from 0. 035 - 0. 071 with an average of 0. 0536. Based on the re-lationship of hydraulic characteristics to discharges and slope gradients, a method to determine hydraulic coeffi-cients of flow in rills are proposed. Data from experiments show that the predicted flow depth of rills using themethod in the paper is close to the observed one. |
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| Keywords: | Erosion Rill Hydraulic characteristics Prediction |
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