横垄渗流及其侵蚀微地貌特征

发布时间：2018-05-27 19:14

本文选题：横坡垄作 + 渗流　；参考：《山东师范大学》2015年硕士论文

【摘要】：渗流对横坡垄作中土壤侵蚀过程有重要的影响，揭示渗流过程以及各种因素对渗流的影响将会加深对横坡垄作渗流侵蚀机制的了解。在横坡垄作中渗流能够促使细沟的产生，且很容易进一步形成浅沟，从而造成大量的土壤侵蚀。增加对细沟形态特征的了解可以为阻止浅沟发展成为冲沟的研究提供研究基础，帮助预测细沟侵蚀量及了解其形态发展规律。在本研究中，通过三元二次正交旋转组合设计安排了23个实验处理，以调查渗流的过程特征以及垄向坡度、坡向坡度以及垄高对渗流的影响。同时研究了横坡垄作渗流侵蚀下的细沟形态特征。渗流过程曲线可分为两种类型：（I）大部分实验呈“S”型，（II）8号实验呈现出稳定增长的趋势。这两种过程曲线都可以用指数模型很好的拟合，且决定系数都在0.995以上。其物理意义与实验结果具有一致性。最大渗流增长率可以在14min以内达到，而渗流基本在106min内才可以达到稳定。用三元二次回归方程对总渗流量以及预测的稳定渗流量进行建模，R2分别为0.66和0.68，模型显著。对于两个模型，只有垄高以及垄向坡度的二次项有显著影响（p 0.05），坡向坡度及其相关项没有显著影响。垄向坡度的单因子影响成一个凹曲线，而垄高则对渗流的单因子影响为正影响并接近线性。在横坡垄作细沟形态特征，细沟沉积特征及其影响因素研究中，，将最大沟宽作为因变量，最大沟深作为自变量，一个线性方程被建立且R2=0.69。最大沟宽与沟深间存在明显的线性关系。把最大沟深纳入细沟体积预测模型，该预测模型为一个复合的幂函数，能够显著的提高预测精度R2从0.67提高到到0.94。通过实验对比发现垄高的增加不只能够促进渗流的产生，并且能够扩展细沟的最大沟宽与沟深。渗流对最大沟宽以及总侵蚀量有双向影响，并且在它们两者的值分别达到17cm和4kg的时候渗流有明显的促进作用，低于此值时为负影响，而对于最大沟深渗流只表现出单一的正影响。根据沉积的位置，细沟沉积可以划分为三种类型：（I）为无沉积；（II）只在垄面上有沉积；（III）垄沟、垄面都有沉积。渗流对垄面沉积量有明显影响，垄向坡度的增加缩短细沟垄面沉积的距离，而垄沟沉积与垄面沉积有明显相关性。
[Abstract]:Seepage plays an important role in the soil erosion process in cross slope ridge cropping. Revealing the seepage process and the influence of various factors on seepage will deepen the understanding of seepage erosion mechanism of cross slope ridge. Percolation in cross slope ridge can promote the formation of rill, and it is easy to form shallow gully, resulting in a large amount of soil erosion. Increasing the understanding of the morphological characteristics of the gully can provide a research basis for the study of preventing the shallow ditch from developing into a gully, and help to predict the erosion amount of the rill and to understand the regularity of its morphological development. In this study, 23 experiments were carried out through a ternary quadratic orthogonal rotation combination design to investigate the characteristics of seepage process and the effects of ridge slope, slope direction and ridge height on seepage flow. At the same time, the morphological characteristics of the rill under percolation erosion were studied. The seepage process curve can be divided into two types: I) most of the experiments show a "S" type of "S" type and the experimental results show a steady growth trend. Both process curves can be fitted well by exponential model, and the determining coefficients are above 0.995. The physical meaning is consistent with the experimental results. The maximum seepage growth rate can be achieved within 14min, while the seepage rate can reach stability in 106min. The model R2 of the total seepage flow and the predicted steady seepage flow is 0.66 and 0.68, respectively, using the ternary quadratic regression equation. The model is significant. For the two models, only the ridge height and the quadratic term of the ridge slope had significant effects on the slope, but the slope and its related items had no significant effect. The single factor effect of ridge slope is a concave curve, while ridge height has a positive effect on seepage flow and is close to linearity. In the study of the characteristics of rill shape, deposition and its influencing factors, the maximum furrow width was regarded as dependent variable, the maximum furrow depth as independent variable, and a linear equation was established and R _ 2 ~ (2 +) _ (0.69) was established. There is an obvious linear relationship between the maximum furrow width and the furrow depth. The maximum furrow depth was incorporated into the rill volume prediction model. The prediction model was a compound power function, which could significantly improve the prediction precision R2 from 0.67 to 0.94. It is found that the increase of ridge height can not only promote the formation of percolation, but also extend the maximum furrow width and furrow depth. Seepage has a bidirectional effect on the maximum channel width and total erosion amount, and has a significant promoting effect when their values reach 17cm and 4kg, but negative effects when they are lower than this value. However, there is only a single positive effect on the maximum trench depth seepage. According to the location of the deposition, the rill deposition can be divided into three types: I) or no sediment (II) only on the ridge surface, the ridge and the ridge are all deposited. Percolation has a significant effect on the deposition amount of ridges, and the increase of ridge gradient shortens the distance between ridge deposition and ridge deposition, while the ridge deposition has obvious correlation with ridge deposition.
【学位授予单位】：山东师范大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：S157

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