摘要
基于可调控的放水冲刷试验,建立黄土高原典型沟壑区坡沟系统试验模型,研究不同放水流量和坡长条件下坡沟系统各过水断面水动力参数的变化特征,为研究坡沟系统水蚀过程作用机理提供科学依据。通过室内放水冲刷试验,采用5个放水流量(6,8,10,12,14L/min)和3个坡长(4,6,8m)研究坡沟系统侵蚀动力因子的坡长效应。结果表明:坡沟系统中沿程各过水断面的雷诺数随放水流量的增大而增大,且不同放水流量和坡长条件下坡面雷诺数明显大于沟道。弗劳德数在坡沟系统中沿程变化过程中逐渐增大,且沟道增长速率明显大于坡面;不同坡长条件下放水流量为10L/min时,弗劳德数远大于其他放水流量。相同放水流量条件下,沟道的径流流速明显大于坡面,坡沟系统的坡面径流流速相对沟道明显稳定且变化范围较小。不同坡长条件下放水流量为10L/min时沿程阻力系数值从2号断面急剧减小到0.03~0.05范围之内,且远小于其他放水流量下同断面的阻力系数值;相同放水流量条件下(除10L/min外),坡长越小,坡面和沟道的波动性相对越小,且坡面处的波动值大于沟道。径流侵蚀功率与雷诺数、弗劳德数、流速显著相关,与雷诺数呈对数函数关系,而与弗劳德数、流速和沿程Darcy-Weisbach阻力系数值呈幂函数关系。研究结果表明,坡长能够影响坡沟系统中坡面和沟道的侵蚀动力因子,并对坡面和沟道沿程侵蚀能量削减和增加效应研究提供重要的科学依据。
Slope-gully model system of the Loess Plateau was established based on the controlled scouring experiments.Study of the effects of slope length on the erosion power factors of slope-gully system could provide scientific guidance for the mechanism of water erosion process in slope-gully system.This study set up five water flow rates（6,8,10,12,14 L/min）and three slope lengths（4,6,8 m）.The results showed that the Reynolds number increased with the increasing water flow rates acrossing each section of the slopegully system,and the Reynolds number in the slope was higher than in the gully.Froude number also increased in the slope-gully system and the increased rate of Froude number in the gully was obviously higher than that in the slope.The Froude number had the highest value when the water flow rate was 10 L/min.The runoff velocity in the gully was obviously higher than in the slope under the same water flow rate,and the runoff velocity in the slope was much stable than in the gully.The resistance coefficients sharply reduced to 0.03~0.05 from section 2 under different slope length and water flow rate of 10 L/min.The fluctuation of resistance coefficients was less with the decreased slope length under the same water flow rate（except for 10 L/min）.Runoff erosion power was significantly correlated with Reynolds number,Froude number,runoff velocity.The relationship between runoff erosion power and Reynolds number was a logarithmicfunction,while the power functions occurred between runoff erosion power and Froude number,flow velocity and resistance coefficients.These results showed that the slope length obviously affected the erosion hydraulic parameters in the slope gully system,and these findings could provide scientific bases for the research of erosion energy transfer in the slope-gully system.
作者
张洋
李占斌
王飞
杨峰
ZHANG Yang;LI Zhanbin;WANG Fei;YANG Feng(Key Lab of Northwest Water Resources and Environment Ecology of Ministry, Education at Xi＇an University of Technology, Xi＇an 710048;State Key Laboratory of Soil Erosion and Dryland Agriculture on Loess Plateau, Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry of Water Resources, Yangling, Shaanxi 712100;Bureau of Upper and Middle Reaches of Yellow River, Xi＇an 710043;Chenggu Soil and Water Conservation Station, Chenggu, Shaanxi 723200)
出处
《水土保持学报》
CSCD
北大核心
2018年第2期97-103,共7页
Journal of Soil and Water Conservation
基金
国家重点研发计划项目(2016YFC0402404)
国家自然科学基金重点项目(41330858)
关键词
坡沟系统
水动力特性
不同坡长
黄土高原沟壑区
slope-gully system
hydrodynamic characteristic
different slope length
Loess Plateau gully region
