急陡黄土坡面土壤剥蚀率变化的水动力学机制研究  

Hydrodynamic Mechanism of Variation in Soil Erosion Rate on Steep Loess Slopes

作　　者：白玉洁 张风宝 杨明义[1,2] 李占斌 张加琼[1,2] BAI Yujie;ZHANG Fengbao;YANG Mingyi;LI Zhanbin;ZHANG Jiaqiong(State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau,Institute of Soil and Water Conservation,Northwest A＆ F University,Yangling,Shaanxi 712100;Institute of Soil and Water Conservation,Chinese Academy of Sciences and Ministry of Water Resources,Yangling,Shaanxi 712100;Institute of Water Resources and Hydro-electric Engineering,Xi＇an University of Technology,Xi＇an 710048)

机构地区：[1]西北农林科技大学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,陕西杨凌712100 [2]中国科学院水利部水土保持研究所,陕西杨凌712100 [3]西安理工大学水利水电学院,西安710048

出　　处：《水土保持学报》2018年第4期1-6,共6页Journal of Soil and Water Conservation

基　　金：国家重点研发计划项目(2016YFC0402406);国家自然科学基金项目(41571130082)

摘　　要：为探明模拟降雨条件下急陡黄土坡面侵蚀产沙的水动力学特征,采用室内模拟降雨的方法研究了6个坡度(25°,30°,35°,40°,45°,50°)和3个雨强(1.0,1.5,2.0mm/min)组合条件下急陡黄土坡面土壤剥蚀率变化规律以及土壤剥蚀率与各水动力学参数之间的关系。结果表明:同坡度下土壤剥蚀率随雨强的增加而增大,相同雨强下坡度对土壤剥蚀率的影响存在临界效应(40°~45°),当坡度小于临界坡度时,土壤剥蚀率随着坡度的增加而增大,当坡度大于临界坡度时,土壤剥蚀率随坡度的增加而减小;径流剪切力、径流功率与过水断面单位能随坡度和雨强的增大均呈增加趋势,其中规律最好的是径流功率;急陡黄土坡面土壤剥蚀率与平均径流剪切力、平均径流功率与平均过水断面单位能均呈幂函数关系,就拟合优度而言,R^2(ω)>R^2(τ)>R^2(E)。因此本试验条件下平均径流功率是描述急陡黄土坡面径流侵蚀的最优水力学参数。This paper oriented to study hydrodynamic characteristics of steep loess slopes（25°~50°）,in an attempt to lay down a foundation for elucidating the in-depth relationships of the hydrodynamic characteristics of shallow water flow on slopes with soil erosion.An indoor experiment was carried out to simulate rainfalls on steep loess slopes.The experiment was designed to have only one soil type（loessal soil）,three rainfall intensities（1.0 mm/min,1.5 mm/min and 2.0 mm/min）and six slope gradients（25°,30°,35°,40°,45° and 50°）.Results showed that：（1）Soil erosion rate increased with rising rainfall intensities on slopes with the same gradient,and under the same rainfall intensity,the effects of slope gradients on soil erosion rate exhibited a critical point in gradient,that was,between 40° and 45°.On slopes with gradient lower than the critical point,soil erosion rate increased with rising slope gradients,whereas on slopes with gradient higher than the point,soil erosion rate decreased with rising slope gradients.（2）Flow shear stress,stream power and unit energy of water-carrying section were increased with the rising rainfall intensities and slope gradients,while stream power had the best regularity.（3）The increasing power functions were found between soil erosion rate with flow shear stress,unite stream power and unit energy of water-carrying section,with the determining coefficient of R^2（ω）〉R^2（τ）〉R^2（E）.So stream power was the best one of all the hydrodynamic parameters tested to describe the soil erosion process on the steep loess slopes.

关 键 词：急陡坡 模拟降雨 侵蚀产沙 水动力学参数 

分 类 号：S157.1[农业科学—土壤学]