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覆沙坡面水动力学参数与径流产沙的关系
引用本文:汤珊珊,李占斌,鲁克新,刘莹,苏远逸,马勇勇.覆沙坡面水动力学参数与径流产沙的关系[J].农业工程学报,2017,33(20):136-143.
作者姓名:汤珊珊  李占斌  鲁克新  刘莹  苏远逸  马勇勇
作者单位:1. 西安理工大学西北水资源与环境生态教育部重点实验室,西安,710048;2. 西安理工大学西北水资源与环境生态教育部重点实验室,西安 710048;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,杨凌 712100
基金项目:国家重点研究与发展项目(2016YFC0402404);国家自然科学基金青年项目(41401305,41601291);国家自然科学基金重点项目(41330858);陕西省自然科学基础研究计划项目(2016JM4017);西安理工大学博士创新基金(310-252071505,310-252071506)
摘    要:坡面流水动学特征对阐明土壤侵蚀和坡面产沙机理均有重要意义,通过模拟降雨试验,定量研究了1.5 mm/min雨强下,不同覆沙厚度(0.5、1.0、1.5 cm)下坡面水动力学参数的时空分布特征及其与产流产沙的关系,以期揭示坡面水动力学参数的内在规律性。结果表明,坡面流的水动力学参数的时空分布呈波动趋势,与黄土坡面相比,雷诺数增加了0.39~1.03倍,佛罗德数增加了0.05~0.29倍,阻力系数增加了0.05~1.55倍;覆沙坡面在整个降雨过程中主要以层流—急流为主,细沟形成主要发生在产流后第10 min后,主要集中在1~10断面处(从坡底依次向上每1 m划分为一个断面);坡面产流和产沙速率与各水动力学参数均可用y=ax+b来描述,雷诺数Re和相对水深曼宁糙率n/h可以较好地表征覆沙坡面侵蚀产沙过程。此研究可为坡面侵蚀预报模型的构建提供科学依据。

关 键 词:侵蚀  径流  产沙  覆沙坡面  覆沙厚度  水动力学参数
收稿时间:2017/5/2 0:00:00

Relationship between hydrodynamic parameters and runoff and sediment yield on sand-covered slope in rainfall simulation study
Tang Shanshan,Li Zhanbin,Lu Kexin,Liu Ying,Su Yuanyi and Ma Yongyong.Relationship between hydrodynamic parameters and runoff and sediment yield on sand-covered slope in rainfall simulation study[J].Transactions of the Chinese Society of Agricultural Engineering,2017,33(20):136-143.
Authors:Tang Shanshan  Li Zhanbin  Lu Kexin  Liu Ying  Su Yuanyi and Ma Yongyong
Affiliation:1. Key Laboratory of Northwest Water Resources and Environment Ecology of MOE, Xi''an University of Technology, Xi''an 710048, China;,1. Key Laboratory of Northwest Water Resources and Environment Ecology of MOE, Xi''an University of Technology, Xi''an 710048, China; 2. State Key Laboratory of Soil Erosion and Dry-land Farming on the Loess Plateau, Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry of Water Resources, Yangling 712100, China;,1. Key Laboratory of Northwest Water Resources and Environment Ecology of MOE, Xi''an University of Technology, Xi''an 710048, China;,1. Key Laboratory of Northwest Water Resources and Environment Ecology of MOE, Xi''an University of Technology, Xi''an 710048, China;,1. Key Laboratory of Northwest Water Resources and Environment Ecology of MOE, Xi''an University of Technology, Xi''an 710048, China; and 1. Key Laboratory of Northwest Water Resources and Environment Ecology of MOE, Xi''an University of Technology, Xi''an 710048, China;
Abstract:Abstract: The change of runoff dynamics on the slope has a decisive effect on the erosion and sediment yield characteristics and erosion intensity. Runoff change is the essence of the hydrodynamic characteristics of soil erosion, runoff is the driving force and the carrier for erosion phenomenon, the change of the hydrodynamic parameters of slope surface flow can reveal some change law of slope runoff, and there is a close relationship between runoff and the hydrodynamic parameters. The deep understanding of the dynamic characteristics of the slope and its variation are the basis for understanding the soil erosion process and the dynamic mechanism of the slope, which is of great significance for the construction of the slope erosion prediction model. We conducted artificial simulated rainfall experiment in the State Key Laboratory of Eco-Hydraulic Engineering at Xi''an University of Technology in China from July to August 2013. We studied quantitatively the temporal and spatial distribution of hydrodynamic parameters on slope and its relationship with runoff and sediment yield under the same rainfall intensity (1.5 mm/min) and different sand-covered thickness (0.5, 1.0, 1.5 cm) in simulated rainfall in order to reveal the internal regularity of hydrodynamic parameters on slope. We also used potassium permanganate (KMnO4) to determinate the flow rate. Hydrodynamic parameters such as Reynolds number Re, Froude number Fr, drag coefficient f and Manning roughness n were used to describe the hydrodynamic characteristics of sand-covered slope and its relationship with runoff and sediment yield. The results showed a fluctuating trend of temporal and spatial distribution of hydrodynamic parameters of the slope flow. As the surface roughness of the slope of the different layer of sand-covered thickness increased, the current flow state became fast and the flow rate increased. Compared with the bare slope, the Re increased by 0.39-1.03 times, the number of Fr increased by 0.05-0.29 times, the f increased by 0.05-1.55 times. In the process of rainfall, the sand-covered slope was mainly composed of laminar flow and turbulence flow. The rill development mainly in middle and later periods of the rainfall (runoff after 10 min) as well as between 1-10 sections (From the bottom of the slope, each 1m is divided into one section) after sand-covered, it had the obvious difference with the loess slope surface, namely loess slope surface rill formed mainly in runoff after 15 min, 1-8 sections (From the bottom of the slope, each 1m is divided into one section). The slope velocity and runoff depth of sand-covered slope were significantly (P<0.05) higher than the bare slope in the middle and later stages of runoff. The relationship between runoff and sediment yield on the slope and the hydrodynamic parameters could be described by y=ax+b. Reynolds number Re and relative depth Manning roughness n/h can better describe the erosion process of sand-covered slope. The results provides data support for the analysis of the sediment yield mechanism and the sand-covered slope erosion production model and provides scientific basis for further researching the coupling mechanism of wind-water alternate erosions and environmental to erosion, and support to further study the effect of wind erosion of water erosion after sedimentation.
Keywords:erosion  runoff  sediment  sand-covered slope  thickness of sand-covered  hydrodynamic parameters
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