摘要
为明确不同植被对沟坡重力侵蚀作用的机理,对7组坡高1.5 m、缓坡3°、沟坡70°、不同植被覆盖的黄土沟坡模型进行降雨模拟试验。结果表明:(1)在暴雨条件下,沟坡系统上植被对崩滑事件的发生有一定的延缓作用,裸地沟坡和植被覆盖沟坡第一次发生重力侵蚀平均时间分别为30.6,35.1 min;(2)植被会减少极大规模重力侵蚀的侵蚀量,增加小规模重力侵蚀的发生频率;(3)短期内植被会增加重力侵蚀速率,长期会减缓重力侵蚀的发展。植被覆盖沟坡的最大重力侵蚀速率是裸地沟坡的3倍,但平均重力侵蚀速率小于相应的裸地沟坡,平均值分别为4.13,5.11 cm^(3)/(m^(2)·s);(4)布置在沟缘线(缓坡和沟坡交界处)附近的植被对重力侵蚀强度及速率有一定的促进作用,沟缘线附近有植被覆盖的最大及平均重力侵蚀速率分别为无植被覆盖的7.6、1.3倍;(5)连翘覆盖沟坡的重力侵蚀强度和速率要高于棣棠覆盖沟坡。因而,在离沟缘线较远处种植根茎较小的灌木并配合工程措施,有助于在植被恢复初期防止沟坡重力侵蚀发生。
In order to demonstrate the mechanism of the effects of the vegetation on the gravity erosion from the gully sidewall,a series of rainfall-simulation experiments were conducted on seven conceptual landforms with a height of 1.5 m,gentle upper slope of 3°,steep lower slope of 70°,and different coverage types of shrubs.The results showed that:(1)under heavy rain conditions,the vegetation coverage on the gully sidewall played a certain role in delaying the occurrence of mass failure;the average times for the first event of gravity erosion on bare-land models(BLMs)and shrubland models(SLMs)were 30.6 min and 35.1 min,respectively;(2)vegetation on the gully sidewall reduced the volume of the extremely large-scale gravity erosion and increased the frequency of small-scale erosion;(3)shrubs increased the rate of the gravity erosion in the short term,and slowed the down development of gravity erosion in the long term;the maximum rate of the gravity erosion on SLMs was 3 times of that on the BLMs,but the average rate of the gravity erosion on the SLMs was lower than that on the corresponding BLMs,of which the average values were 4.13,5.11 cm^(3)/(m^(2)·s),respectively;(4)the vegetation arranged near the junction of the steep slope and gentle slope(gully-edge line)had a certain promotion effect on the intensity and rate of gravity erosion;the maximum and average rates of the gravity erosion on the SLMs with the vegetation coverage near the gully edge line were 7.6 and 1.3 times of those under no vegetation,respectively;(5)the intensity and rate of gravity erosion on the SLMs with Forsythia suspensa coverage were higher than those with Kerria japonica coverage.Hence,planting vegetation with smaller rhizomes far away from the gully-edge line together with structural practices can help to prevent the gravity erosion on the gully sidewall in the initial stage of vegetation restoration.
作者
高航
徐向舟
肖培青
张红武
GAO Hang;XU Xiangzhou;XIAO Peiqing;ZHANG Hongwu(School of Hydraulic Engineering,Dalian University of Technology,Dalian,Liaoning 116024,China;Key Laboratory of Soil and Water Loss Process and Control on the Loess Plateau,Ministry of Water Resources,Zhengzhou 450003,China;State Key Laboratory of Hydroscience and Engineering,Tsinghua University,Beijing 100084,China)
出处
《水土保持研究》
CSCD
北大核心
2021年第6期17-24,共8页
Research of Soil and Water Conservation
基金
国家重点研发计划项目(2016YFC0402504)
国家自然科学基金面上项目(51879032)
水利部黄土高原水土流失过程与控制重点实验室开放课题基金(201903)。
关键词
降雨模拟
重力侵蚀
植被
重力侵蚀速率
黄土沟坡
rainfall simulation
gravity erosion
vegetation
gravity erosion rate
sidewall of loess gully
