模拟径流条件下覆沙黄土坡面产流产沙过程

发布时间：2018-07-10 07:33

本文选题：风水复合侵蚀 + 冲刷试验　；参考：《水土保持学报》2017年04期

【摘要】：基于可调控的放水冲刷试验,模拟风水复合侵蚀区典型覆沙黄土坡面,研究不同径流条件下覆沙黄土坡面产流产沙过程。通过室内放水冲刷试验,采用3个放水流量(5,10,15L/min)和5个覆沙厚度(0,5,15,25,35mm)研究覆沙黄土坡面产流产沙过程。结果表明:覆沙坡面能够延长产流时间,且随覆沙厚度的增大而延长,不同放水流量条件下5,15,25,35 mm覆沙坡面的产流时间较黄土坡面分别延迟了1.29~1.46倍,1.66~2.5倍,2.32~3.76倍和3.64~4.72倍;覆沙坡面相对黄土坡面其产沙贡献率大于产流贡献率,在相同放水流量条件下,覆沙坡面的径流总量是黄土坡面的1.05~1.8倍,而产沙总量是黄土坡面的1.6~7.5倍;覆沙坡面在不同放水流量条件下,产流0~5min内,覆沙坡面产流率增长速率明显高于黄土坡面,而在后25min覆沙坡面与黄土坡面的产流率增长速率基本一致;在整个产流阶段,覆沙坡面的产流率波动程度显著高于黄土坡面。随着放水流量的增大,覆沙坡面的初始产沙强度显著增加;但在同一放水流量前提下,随着覆沙厚度的增大初始产沙强度增强不显著。不同放水流量和不同覆沙厚度条件下坡面产沙强度总体上表现为先剧烈增大后降低然后逐步达到平稳状态,且覆沙坡面产沙强度的波动性明显活跃于黄土坡面。覆沙坡面能够破坏水流的稳定性,在一定程度上加剧了土壤侵蚀。
[Abstract]:Based on the controlled flushing test, the typical sandy loess slope surface in the geomantic complex erosion area was simulated, and the sediment yield and abortion process of the sand covered loess slope surface under different runoff conditions were studied. In this paper, the process of runoff and sediment production on loess slope with sand cover was studied by using three water discharge (5 ~ 10 ~ 15 L / min) and five sediment thickness (0 ~ 5 ~ 5 ~ 15 ~ 25 ~ 25 ~ (35 mm) by indoor flushing test. The results show that the runoff production time can be prolonged on the sand covered slope surface with the increase of sediment thickness, and the runoff time of the sand covered slope surface at different discharge rate is 1.29 ~ 1.46 times 1.66 ~ 1.46 times ~ 2.32 ~ 3.76 times and 3.644.72 times longer than that of the loess slope surface, respectively. The sediment yield contribution rate of the sandy overlying slope is greater than the runoff yield contribution rate of the loess slope surface. Under the same water discharge flow, the total runoff on the covered sandy slope surface is 1.05 ~ 1.8 times of that on the loess slope surface, and the total sediment yield is 1.6 ~ 7.5 times that on the loess slope surface. Under the conditions of different water discharge, the increase rate of runoff yield on the sandy overlying slope is obviously higher than that on the loess slope, but the increase rate of runoff rate is basically the same on the post-25min sandy slope surface and the loess slope surface, and in the whole runoff generation stage, the increase rate of the runoff yield rate of the sand covered slope is higher than that of the loess slope surface, and the increase rate of the flow rate is similar to that of the loess slope surface. The fluctuation degree of runoff rate on the covered slope is significantly higher than that on the loess slope. With the increase of water discharge, the initial sediment yield intensity increased significantly, but under the same discharge rate, the initial sediment yield intensity increased with the increase of sediment thickness. Under the conditions of different discharge flow and different sediment cover thickness, the sediment yield intensity on the slope increases sharply and then decreases and then reaches a steady state, and the fluctuation of sediment yield intensity is active on the loess slope surface. The slope covered with sand can destroy the stability of water flow and aggravate soil erosion to some extent.
【作者单位】：西安理工大学西北旱区生态水利工程国家重点实验室培育基地;中国科学院水利部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;中交第一公路勘察设计研究院有限公司;
【基金】：国家自然科学基金重点项目(41330858);国家自然科学基金项目(41471226)
【分类号】：S157.1

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