典型黑土区坡面土壤侵蚀影响因素与动力学机理研究

发布时间：2018-03-03 00:28

  本文选题：降雨和汇流　切入点：地表条件　出处：《中国科学院研究生院(教育部水土保持与生态环境研究中心)》2016年博士论文　论文类型：学位论文

【摘要】：研究黑土区坡面侵蚀影响因素将为黑土区侵蚀防治和黑土资源保护提供重要的科学依据。本文以吉林省榆树市典型黑土区坡面土壤为研究对象,以降雨和汇流两种侵蚀动力为切入点,采用模拟降雨和上方汇流试验相结合的研究方法,阐明侵蚀动力条件(降雨能量、降雨强度和上方汇流)和地表条件(坡度、坡长、土壤结皮和翻耕深度)对黑土区坡面侵蚀过程的影响,揭示黑土区坡面侵蚀的水动力学机理。主要研究结论如下:(1)分析了降雨能量、降雨强度和汇流强度对黑土区坡面土壤侵蚀的影响。与消除降雨能量的试验条件相比,有降雨能量试验条件下的坡面径流量仅增加了12.8%~39.7%,而坡面侵蚀量则增加了1.7~1.9倍。降雨强度由50 mm h-1增加到100mm h-1时,坡面径流量和侵蚀量分别增加了1.4~12.4和4.2~6.1倍。汇流强度对坡面侵蚀过程的影响受坡面侵蚀方式的影响。当坡面以片蚀为主时,汇流强度由50 L min-1增加到150 L min-1,坡面侵蚀量无显著性变化,而当汇流强度由150 L min-1增加到300 L min-1,坡面侵蚀量呈明显增加趋势。而当坡面以细沟侵蚀为主时,坡面侵蚀量随汇流强度的增加而呈明显的增加趋势;与汇流强度50 L min-1相比,汇流强由100 L min-1增加到300 L min-1时,坡面侵蚀量增加了6.2~61.7倍。(2)剖析了降雨和汇流两种侵蚀动力条件下地形因子和地表条件对坡面侵蚀特征的影响。降雨侵蚀动力条件下,坡长由5 m增加到10 m时,在相同降雨强度和坡度试验条件下,坡面径流量和侵蚀量分别增加了0.1~3.1和2.1~2.9倍;坡度由5°增加到10°时,在相同降雨强度和坡长试验条件下,坡面侵蚀量增加了0.4~0.9倍。汇流侵蚀动力条件下,汇流强度由50 L min-1增加到300 L min-1时,坡度由5°增加到10°引起坡面侵蚀量增加了2.6~201.0倍。地表结皮对坡面侵蚀的影响受降雨强度、坡度和坡长的综合影响。翻耕深度由5 cm增加到20 cm时,坡面侵蚀量变化受降雨强度和坡度的综合影响;而汇流侵蚀动力条件下坡面侵蚀量变化随翻耕深度的变化受坡面侵蚀方式的影响。(3)分析了降雨和汇流两种侵蚀动力条件下影响黑土区坡面侵蚀的主要因素。降雨侵蚀动力条件下影响坡面侵蚀的主要因素是坡长;并建立了坡面侵蚀量与坡长、降雨强度—坡长交互作用的经验关系式。汇流侵蚀动力条件下影响坡面侵蚀的主要因素是汇流强度—坡度交互作用;建立了坡面侵蚀量与汇流强度—坡度交互作用的经验关系式;汇流侵蚀动力条件下坡面侵蚀量与径流量相关关系受侵蚀方式的影响较为明显。(4)探究了降雨侵蚀动力条件下的坡面侵蚀的水动力学机理。随降雨强度、坡度和坡长的增加,径流流速、雷诺数和弗汝德数均呈增加趋势,而Darcy-Weisbach阻力系数则呈减少趋势。土壤结皮的存在使得坡面Darcy-Weisbach阻力系数降低了25.6%~40.3%。翻耕深度由5 cm增加到20 cm时,坡面平均流速降低了36.8%~40.2%,Darcy-Weisbach阻力系数则分别增加了1.5~1.8倍。降雨侵蚀动力条件下坡面侵蚀量与径流剪切力、径流功率以及单位径流功率间无显著的线性关系;而坡面侵蚀量与径流流速和弗汝德数呈极显著正相关关系,与Darcy-Weisbach阻力系数呈显著负相关关系。(5)探讨了上方汇流侵蚀动力条件下的坡面侵蚀水动力学机理。随汇流强度和坡度的增大,径流平均流速、雷诺数和弗汝德数均有所增加;Darcy-Weisbach阻力系数则逐渐降低。翻耕深度对坡面水力学参数的影响受坡度和汇流强度的综合影响。分别建立了坡面侵蚀侵蚀量与径流剪切力、径流功率和单位径流功率的关系式。径流流速和单位水流功率是表征坡面侵蚀的最佳水力学和水动力学参数。
[Abstract]:Will provide important scientific basis for the prevention of erosion in black soil region and black soil resources protection slope erosion influence factors of black soil area. Taking soil slope in typical black soil in Yushu city of Jilin Province as the research object, with rainfall and two kinds of runoff erosion power as the starting point, the simulation methods of rainfall and runoff over the test combination. To clarify the erosion dynamic conditions (rainfall intensity and rainfall runoff energy, above) and surface conditions (slope, slope length, soil crust and ploughing depth) influence on the process of black soil erosion of slope, reveal the hydrodynamic mechanism of slope erosion in black soil region. The main conclusions are as follows: (1) analyzed rainfall energy. The intensity of rainfall intensity on the influence and confluence in black soil zone of slope soil erosion. Compared with the experimental conditions to eliminate rainfall energy, rainfall energy test under the condition of runoff increased by only 12.8%~39.7%, and slope The erosion amount is increased by 1.7~1.9 times. The rainfall intensity increased from 50 mm H-1 to 100mm H-1, slope runoff and soil erosion were increased 1.4~12.4 and 4.2~6.1 times. Effect of intensity on the slope erosion process of runoff is affected by soil erosion patterns. When the slope in sheet erosion, runoff intensity increased by 50 L min-1 L to 150 min-1, the slope erosion and no significant changes, and when the concentration increased from 150 L to 300 L min-1 min-1 increased, the slope erosion was significantly increased. When the slope in rill erosion is increased with slope erosion intensity and concentration were increased; compared with the bus the intensity of 50 L min-1, the confluence of strong increases from 100 L to 300 min-1 L min-1, the rate of soil erosion increased by 6.2~61.7 times. (2) analyzed the influence of the rainfall and the confluence of two kinds of erosion under dynamic conditions topography and surface conditions on the erosion characteristics of the slope. Under the condition of rainfall erosion force, slope length increased from 5 m to 10 m, in the same rainfall intensity and slope conditions, slope runoff and soil erosion were increased 0.1~3.1 and 2.1~2.9 times; the slope increased from 5 degrees to 10 degrees, in the same rainfall intensity and slope length under the experimental conditions, the slope erosion the amount of 0.4~0.9 times. The confluence of erosion under dynamic conditions, convergence intensity increased from 50 L to 300 min-1 L min-1, the slope from 5 degrees to 10 degrees increase caused by slope erosion increased by 2.6~201.0 times. Surface crust by the impact of rainfall intensity on soil erosion on the slope, slope and slope length of the comprehensive effect of tillage. The depth increased from 5 cm to 20 cm, the slope erosion changes affected by the rainfall intensity and slope runoff erosion; and dynamic conditions of slope surface erosion varies with the depth of ploughing is affected by soil erosion patterns. (3) analysis of the rainfall and the confluence of two kinds of erosion Main factors affecting the soil area of slope erosion under dynamic conditions. The rainfall erosion under dynamic conditions are main factors affecting soil erosion on the slope and slope length; established slope erosion and slope length, empirical formula of rainfall intensity, slope length interaction. The confluence of erosion dynamical conditions, main factors affecting soil erosion intensity is confluence slope interaction; established empirical formula of slope erosion and runoff intensity slope interaction; runoff erosion power slope erosion and runoff relationship affected by erosion is obvious. (4) to explore the dynamic mechanism of water erosion under dynamic conditions of slope erosion. With the rainfall intensity. The slope and the slope length increases, the runoff velocity, Reynolds number and Froude number increased, while the Darcy-Weisbach resistance coefficient decreased. Soil crusts are the slope Darcy-Weisbach resistance coefficient decreased 25.6%~40.3%. ploughing depth increased from 5 cm to 20 cm, the average flow rate decrease 36.8%~40.2%, Darcy-Weisbach resistance coefficient was increased by 1.5~1.8 times. The rainfall erosion dynamic conditions of slope surface erosion and runoff shear stress, no significant linear relationship between runoff and runoff power unit power and slope; soil erosion and runoff velocity and Vladimir positive correlation was found between the Froude number, there was a significant negative correlation between resistance coefficient and Darcy-Weisbach. (5) discussed the dynamic mechanism of slope water erosion above the confluence of erosion under dynamic conditions. With the increase of runoff intensity and slope runoff, average flow velocity, Reynolds number and Froude the number of Darcy-Weisbach increased; resistance coefficient decreased. Effect of tillage depth on the slope hydraulics parameters affected by the slope and discharge intensity were established. The relationship between erosion and erosion amount and runoff shear force, runoff power and unit runoff power is also discussed. Runoff velocity and unit flow power are the best hydraulic and hydrodynamic parameters to characterize slope erosion.

【学位授予单位】：中国科学院研究生院(教育部水土保持与生态环境研究中心)
【学位级别】：博士
【学位授予年份】：2016
【分类号】：S157.1
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本文编号：1558778