| 中文题名： | 基于SfM摄影测量的细沟与细沟间侵蚀实验研究 |
| 姓名： | |
| 保密级别： | 公开 |
| 论文语种： | 中文 |
| 学科代码： | 070502 |
| 学科专业： | |
| 学生类型： | 学士 |
| 学位： | 理学学士 |
| 学位年度： | 2020 |
| 学校： | 北京师范大学 |
| 校区： | |
| 学院： | |
| 第一导师姓名： | |
| 第一导师单位： | |
| 提交日期： | 2020-06-27 |
| 答辩日期： | 2020-05-25 |
| 外文题名： | EXPERIMENTAL RESEARCH ON RILL AND INTERRILL EROSION BASED ON SFM PHOTOGRAMMETRY |
| 中文关键词： | |
| 外文关键词： | Interrill erosion ; Rill erosion ; Structure from Motion (SfM) photogrammetry ; Digital elevation model (DEM) ; Rill morphology |
| 中文摘要： |
细沟与细沟间侵蚀是重要的土壤侵蚀类型，建立一套简便、精确的监测方法对于开展细沟与细沟间侵蚀定量研究，探讨土壤侵蚀机理，指导区域水土保持规划具有重要意义。近年来，基于运动恢复结构（Structure from Motion，SfM）的摄影测量法因其高精度、高效率、低成本的优点开始广泛应用于多个领域。本研究采用人工模拟降雨试验，分析坡度对黄土坡面细沟与细沟间侵蚀产流、产沙过程的影响；并利用SfM摄影测量法研究细沟与细沟间侵蚀的演变过程，得到主要结论如下。（1）当坡度为10°时，产流时间最长，当坡度大于15°时，产流时间无明显变化；累积产流量随坡度总体呈减小趋势。（2）实测累积产沙量随坡度呈先增加后减少的趋势，临界坡度介于20°~25°之间。（3）坡面首先发生细沟间侵蚀，土表高程总体降低；随着降雨持续，细沟率先在坡面中下部和小区边壁出现；通过上溯下切、沟壁崩塌和细沟合并，细沟规模不断扩大。（4）由于黄土的湿陷特征，SfM所测产沙量高于实测量，尤其是在降雨侵蚀的早期阶段，但累积产沙量的坡度变化规律与实测产沙量一致。（5）细沟几何特征参数（长度、平均宽度、平均深度、面积、体积）随坡度呈先增后减趋势，临界坡度介于20°~25°之间。
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| 外文摘要： |
Rill and interrill erosion are important soil erosion types. Establishing a simple and accurate monitoring method is of great significance in quantifying rill and interrill erosion, exploring soil erosion mechanism, as well as guiding regional soil and water conservation planning. During recent years, the structure from motion (SfM) photogrammetry has been applied to many different research fields due to its advantages of high precision, high efficiency and low cost. In the current study, a rainfall simulation experiment was performed on a loess slope to analyze the impact of slope gradient on the runoff and sediment resulting from rill and interrill erosion. The SfM photogrammetry was used to examine the evolution of the rill and interrill erosion. The main conclusions are presented as below. (1) The initial time for runoff yielding was the longest for the 10° slope treatment; whereas no apparent difference was manifested in the times for the other slope treatments. As the slope gradient increased, the cumulative runoff volume generally decreased. (2) The cumulative sediment load as measured by runoff and sediment collection showed an increasing trend, followed by a decreasing one, with the increase of slope gradient. The critical slope was expected to fall within the range of 20°~25°. (3) Only interrill erosion occurred at the beginning of the rainfall simulation, accompanied by the decrease of soil surface elevation. As the rainfall continued, small rills developed in the lower middle section of the slope and next to the sidewall of plot. The sizes of the rills increased with time, mainly via headcutting and downcutting, rill bank collapse and merging of adjacent rills. (4) Owing to the collapsibility of loess, the sediment loads measured by SfM were generally greater than those by runoff and sediment collection, especially in the early stages of rainfall simulation. Yet the trend of the cumulative sediment yield with slope gradient obtained by SfM was overall consistent with that by the collection method. (5) As the slope gradient increased, the rill morphological parameters (length, average width, average depth, area, and volume) also increased initially and then decreased, with a critical gradient approximately between 20° and 25°.
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| 参考文献总数： | 49 |
| 插图总数： | 13 |
| 插表总数： | 1 |
| 馆藏号： | 本070502/20013 |
| 开放日期： | 2021-06-27 |
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