【作者】 付凌；

【导师】 彭世彰； 时明立；

【作者基本信息】 河海大学 ， 农业水土工程， 2007， 硕士

【摘要】 在人类活动的影响下，黄土高原地区的下垫面条件发生了很大变化，这种变化影响了流域的产流输沙特性。以黄河中游典型流域岔巴沟为研究区域，分析了20世纪60年代、70年代、80年代和90年代的水沙变化趋势及其成因。利用水文法和水保法这两种方法分析岔巴沟小流域的输沙变化趋势，并根据沙量平衡原理对淤地坝的间接减蚀作用进行了定量分析。以上内容得出淤地坝具有较大的拦沙减蚀能力特别是拦减粗泥沙的能力，所以在此基础上又进一步研究了淤地坝对泥沙颗粒级配的影响。主要得出以下结论： 采用水文法原理计算时用分布式水文模型代替以往的经验模型，计算结果表明：水土保持措施在一定条件下对较小暴雨有更好的拦蓄作用；淤地坝有一定的拦蓄作用，但对超标准洪水的拦蓄作用有限。 利用水保法计算各单项措施的拦沙量时，考虑了面积差异、质量标准、降雨水平等因素的影响，对坡面措施指标进行了一定的修正，结果表明，淤地坝以较小的配置比例取得了较大的拦沙效益。 根据沙量平衡原理，定量地计算出了淤地坝的间接减蚀量，虽然水文法和水保法在计算中均存在一定的误差，但总的来说，坝地的间接减蚀作用是很明显的。 淤地坝淤积物的颗粒级配在水平方向上存在明显的差异，表现为上游较下游粗，淤地坝具有明显的淤粗排细作用。 淤地坝淤积面有一定的纵比降，尾部存在显著的“翘尾巴”现象。并且已溃决的淤地坝其拦蓄泥沙的能力并没有立即终止，而是具有一定的滞后性。更多还原

【Abstract】 The underlying surface conditions of Loess plateau area have been changing great because of human activity, which results in affecting the features of producing run-off and conveying sand. We take the typical Chabagou Catchment from the middle reaches of Yellow River as the research area, analysing the variation tendency and cause of Water and Sediment during 1960s, 1970s, 1980s, 1990s. The article analyses variation tendency of sand-conveying through soil and water conservation benefits method and hydrological method, and take quantitative analysis to indirect erosion-reducing function of soil-retaining dams according to the principle of sand-balance. It comes to a result that the soil-retaining dams have greater ability of sand-blocking and erosion-reducing especially blocking and reducing wide sand, therefore, we further study the influence of the soil-retaining dams to the sediment grain size based on talk above. Drawing out the following main conclusions :When calculating producing run-off,we use the distributed hydrologic model instead of empirical model,the computing results of hydrological method: It indicates that the soil and water conservation measures have better retaining function to little torrential rain under certain circumstances; Although the soil and water conservation measures such as soil-retaining dams have definite retaining effect, it limits to retain superstandard floor.Caculating the sand-blocking amount of each single step, considering the influences from area difference, quality criterion, rainfall level etc, the article gives a certain rectification to slope measures indexes. From the computing results of soil and water conservation benefits method, we know that soil-retaining dams got greater benefits with less configuration ratio.According to the principle of sand-balance, it quantitatively computed indirect erosion reduction of soil-retaining dams. The water conservation benefits method and hydrological method both have certain error, but in all, the indirect erosion-reducing effect of dams is very obvious.The sediment grain size have notable diversity in horizon, expressing the drifts from upper reaches are thicker than the ones from lower reaches, soil-retaining dams possessing evident function of retaining the thick and discharging the thin.The depositing surface of soil-retaining dams has certain vertical gradient, the tail exists obvious phenomenon of "raising tails". And the retaining sediment abilities of burst soil-retaining dams doesn’t stop at once, but it has certain hysteresis.更多还原