| 坡面细沟侵蚀断面形态发育影响因素分析及动力特性试验 |
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| 引用本文： | 马小玲,张宽地,杨帆,杨明义,董旭.坡面细沟侵蚀断面形态发育影响因素分析及动力特性试验[J].农业工程学报,2017,33(4):209-216. |
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| 作者姓名： | 马小玲 张宽地 杨帆 杨明义 董旭 |
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| 作者单位： | 1. 西北农林科技大学水利与建筑工程学院,杨凌,712100;2. 西北农林科技大学水利与建筑工程学院,杨凌 712100;中国科学院水利部水土保持研究所黄土高原土壤侵蚀与旱地农业国家重点实验室,杨陵 712100;3. 中国科学院水利部水土保持研究所黄土高原土壤侵蚀与旱地农业国家重点实验室,杨陵,712100 |
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| 基金项目： | 国家自然科学基金资助项目"坡面含沙水流波流耦合特性及泥沙输移机理研究"（51579214）,中央高校基本科研业务费专项资金"黄土坡面含沙水流能量耗散规律研究"（Z109021564）;黄土高原土壤侵蚀与旱地农业国家重点实验室主任基金"基于超声测量技术研究坡面流流动特性"（A314021402-1619）;流域水循环模拟与调控国家重点实验室开放基金"坡面滚波演化及挟沙能力研究"（IWHR-SKL-2014） |
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| 摘 要： | 研究细沟形态发育过程对认识细沟侵蚀具有重要作用,该文采用6种坡度(2°、4°、6°、8°、10°、12°),5种流量(8、16、24、32、40 L/min)下的组合冲刷试验,系统研究了坡面细沟横纵断面形态发育影响机制及动力特性。结果表明:细沟宽深比变化范围为3.006~4.884,根据水力最佳断面,细沟水流远未达到稳定。横断面形态系数随坡度的变化范围为0.36~0.522,细沟横断面形态随流量、坡度以及冲刷历时均趋近于梯形水力最佳断面,即阻力最小的断面。随着流程长度的增加,横断面形态由宽深逐渐变窄,横断面形态系数也随之减小。细沟纵断面形态范围为0.60~11.26,且随坡度的增大而增大,与流量相关性不大。综合阻力系数及消能率均与细沟纵断面形态系数呈良好的幂函数关系。
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| 关 键 词： | 侵蚀 试验 土壤 细沟形态 形态指标系数 跌坑 消能率 |
| 收稿时间： | 2016/6/22 0:00:00 |
| 修稿时间： | 2017/1/3 0:00:00 |
Influencing factor analysis of rill erosion section morphology development on slope and its dynamic characteristic experiment |
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| Ma Xiaoling,Zhang Kuandi,Yang Fan,Yang Mingyi and Dong Xu.Influencing factor analysis of rill erosion section morphology development on slope and its dynamic characteristic experiment[J].Transactions of the Chinese Society of Agricultural Engineering,2017,33(4):209-216. |
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| Authors: | Ma Xiaoling Zhang Kuandi Yang Fan Yang Mingyi and Dong Xu |
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| Institution: | 1. College of Water Resources and Architectural Engineering, Northwest A&F University, Yangling, 712100, China;,1. College of Water Resources and Architectural Engineering, Northwest A&F University, Yangling, 712100, China; 2. State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Northwest A&F University, Yangling 712100, China;,1. College of Water Resources and Architectural Engineering, Northwest A&F University, Yangling, 712100, China;,2. State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Northwest A&F University, Yangling 712100, China; and 1. College of Water Resources and Architectural Engineering, Northwest A&F University, Yangling, 712100, China; |
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| Abstract: | Abstract: Rill erosion is the process of soil particles separating in the groove and handling by rill flow, and it is one type of surface corrosion, and the rill formed can be completely filled by normal farming activities. In the loess plateau region, rill erosion of slope accounts for more than 70% of the total erosion, and rill erosion is a major erosion in the loess plateau hilly land, and is also an important part of mechanism of slope erosion prediction. Rills are small channels which function as both sediment sources and sediment transport vehicles on hill slopes. It is a quantum leap during the process of soil erosion on slopes, and is also the beginning of qualitative changes in the process of soil erosion. The rill morphology development plays an important role in the understanding of rill erosion. Rill morphology changes have many influence factors in the process of rill erosion, so systematically studying the relationship between rill shape coefficient and influencing factors can make us better understand the process of rill erosion and erosion mechanism. For the study of rill morphological development process, the combination scouring tests of 6 slopes (2°, 4°, 6°, 8°, 10°, and 12°) and 5 discharges (8, 16, 24, 32, and 40 L/min) were carried out, and the effect mechanism of rill transverse profile morphological development on the loess slope surface was investigated, as well as the dynamic characteristics of the impact. The results showed that rill width-depth ratio ranged from 3.006 to 4.841, and according to the hydraulic optimum section, the rill flow was far from steady state. In rill erosion, downward erosion and lateral erosion gradually transited to downward erosion. Because of incised and lateral erosion, rill cross-sectional shape was gradually widened and deepened with the increase of slope and time. Along with the change of slope, cross-sectional shape coefficient varied within the range of 0.36-0.522. Research showed that: The rill cross-sectional shape was approximating to the trapezoidal hydraulic best section with the increase of the flow, slope and scour lasted time, namely the section with the least resistance. With the increase of water flow length, cross section shape changed gradually from wide and deep to narrow, and the cross-sectional shape coefficient was reduced. Through calculation, the groove profile form ranged within 0.6-11.26, and increased with the increase of slope, but had no significant correlation with discharge. With the increase of slope, the average spacing of drop pit on bed face decreased, the depth of drop pit increased, and the groove profile shape coefficient increased. Comprehensive resistance coefficient and energy dissipation showed a good power function relationship with groove profile shape coefficient, and with the increase of profile shape coefficient, the slope shape resistance increased. Rill hydraulic characteristics and groove shape showed the role of mutual connection and restriction and reaction system. Groove profile shape coefficient was larger, the bed surface shape resistance increased, and drop pit also would be developed more maturely. The water in drop pit had strong turbulence and aeration, which had significant effect on energy dissipation. |
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| Keywords: | erosion experiment soils rill morphology form index coefficient drop pit energy dissipation efficiency |
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