Headwall scour hole erosion and overhanging mass collapse play critical roles in gully head retreat on grassland under surface flow
Headwall scour hole erosion and overhanging mass collapse play critical roles in gully head retreat on grassland under surface flow
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头壁冲刷孔侵蚀和悬垂体塌陷对地表流下草地沟头退缩起着关键作用
DOI：
10.1016/j.geomorph.2022.108301
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发表时间：
2022-08
期刊：
影响因子：
3.9
通讯作者：
Hai Xiao
中科院分区：
文献类型：
--
作者：
Hongliang Kang;Wenlong Wang;Mingming Guo;Jianming Li;Zhuoxin Chen;Yibao Lou;Wenzhao Guo （郭文召）;Hai Xiao
虽然植被恢复控制了沟头退缩，但在全球气候变化引起的暴雨过程中，植被覆盖区的沟头仍可能退缩。然而，GHR的过程和机制的生长激素的植被覆盖的土地上还不清楚。以典型草地紫花苜蓿（Medicago sativa L.）主要是在不同来流率（3.6 - 9.6 m3 h − 1）下，探讨了地表水流诱发的GHS的水力和物质运动特性、形态演变和产沙过程。结果表明：射流占主流，占入流量的51.94%~63.33%，壁面流（含渗流）流量在1.40~3.08 m3 h-1范围内呈线性增加，但其比例随入流量的增加而减小。由于沿墙水流冲刷、渗流和冲坑坍塌，冲坑会逐渐在端墙上形成，形成悬挑体。研究了不同来流率下冲沟首墙悬挑体崩塌的临界冲坑尺寸。此外，GHOC发生在较高的来流率，这是与更显着的增长率下，较高的壁面流量的冲刷坑尺寸。水垫塘在GHOC之前获得最大深度和长度，并且所应用的流入速率越高，观察到的最大深度和长度越高。产沙率随时间变化呈波动性下降，最大值为初始值的1.60-5.06倍。水垫塘侵蚀对GHR的影响有限，而端墙上的冲刷坑发展和随后的悬挑块体崩塌对地表流下草地的GHR起着关键作用。·对射流和壁面流进行了划分和研究。·对冲沟头墙冲刷坑的发育进行了研究。·冲坑侵蚀和草原上悬块崩塌导致沟头后退。
Although vegetation restoration controls gully head retreat (GHR), gully heads (GHs) could still retreat on vegetation-covered lands under intensifying rainstorms induced by global climate change. However, the GHR processes and mechanisms for GHs on vegetation-covered lands are unclear. A series of simulated experiments were conducted on a typical grassland ( Medicago sativa L. dominated) under different inflow rates (3.6–9.6 m 3 h −1 ) to explore the hydraulic and mass movement properties, morphology evolution, and sediment yield process of GHs induced by surface flow. The results show that the jet flow dominated and accounted for 51.94%–63.33% of the inflow volume; the on-wall flow (including seepage flow) rate linearly increased from 1.40 to 3.08 m 3 h −1 , while its proportion decreased with increasing inflow rate. A scour hole could gradually develop on the headwall due to the on-wall flow scouring, seepage, and scour hole collapse, resulting in an overhanging mass. A critical scour hole size was observed when the gully headwall overhanging mass collapse (GHOC) occurred under different inflow rates. Additionally, GHOC occurred earlier under the higher inflow rate, which was associated with the more significant increasing rate of the scour hole size under the higher on-wall flow rate. The plunge pool obtained the maximum depth and length before the GHOC, and the higher the inflow rate that was applied, the higher the maximum depth and length that were observed. The sediment yield rate decreased over time with fluctuations, and the maximum values resulting from the GHOCs were 1.60–5.06 times the initial values. Plunge pool erosion had limited effects on GHR, while scour hole development on the headwall and subsequent overhanging mass collapse played critical roles in GHR on grassland under surface flow. • Jet flow and on-wall flow were divided and investigated. • The scour hole development on gully headwall was explored. • Gully head retreated as scour hole erosion and overhanging mass collapse on grassland.
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影响因子：
2.4
作者：
O. Stein;P. Julien
通讯作者：
O. Stein;P. Julien
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影响因子：
1.6
作者：
Zhang Baojun;Xiong Donghong;Su Zhengan;Yang Dan;Dong Yifan;Xiao Liang;Zhang Su;Shi Liangtao
通讯作者：
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影响因子：
5.4
作者：
I. Prosser;M. Soufi
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I. Prosser;M. Soufi
影响因子：
6.4
作者：
M. Guo;Lou Yibao;Zhuo-xin Chen;Wen-long Wang;Lanqian Feng;Xingyi Zhang
通讯作者：
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影响因子：
3.3
作者：
F. Rengers;G. Tucker
通讯作者：
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