摘要
细沟侵蚀水力学特征参数与侵蚀后微地形变化间的关系是深入探究细沟侵蚀的重要机理。本文以黄绵土为研究对象,设置4个坡度5°、10°、15°、20°,4个流量2、4、8、16 L·min^(-1),采用宽0.10 m的限定性细沟模拟冲刷试验,结合运动恢复结构摄影测量法,分析了坡面细沟水力学特征参数与微地形变化间的关系。结果表明:试验条件下,流速的变化范围为0.23~0.92 m·s^(-1),坡度较流量对流速的影响大;雷诺数和弗劳德数的变化范围分别为255~2358和1.89~5.90,上述水力学特征参数均随坡度和流量增大而增大(P<0.05),阻力系数则相反。地表粗糙度、地形起伏度和地表切割深度的变化范围分别为0.33~2.35、0.47~4.35和0.53~2.53 cm,3个微地形因子与流速、雷诺数、弗劳德数之间呈正相关性,与阻力系数呈负相关性,且随流速和雷诺数的增加分别呈线性和幂函数增加的趋势。综上,随着坡度和流量的增大地表微地形因子均有不同程度的增大,标志着坡面微地形向着有利于侵蚀发生的方向进行。水流的水力学特征参数(如流速、雷诺数)对地表微地形变化具有显著影响,地表粗糙度、地形起伏度和地表切割深度对流速和雷诺数变化的响应遵循线性和幂函数关系,小流量时地表粗糙度变幅最大,随着流量增大,地表起伏度和地表切割深度变幅逐渐增大,表明侵蚀过程中径流下切作用强烈,细沟侵蚀深度不断增大。研究结果可为黄绵土坡耕地水土流失治理工作以及区域生态修复研究提供理论支撑。
【Objective】This study aimed to investigate the relationship between the hydraulic characteristic parameters of rill erosion and the changes in microtopography of the eroded,which is an important mechanism for investigating rill erosion.【Method】In this study,the loess was selected as the research material,and four slopes gradients(5°,10°,15°,20°)and four flow rates(2,4,8,16 L·min^(-1))were set.The limited rills with a width of 0.1 m were used to simulate the rill erosion experiment,combined with Structure-from-Motion(SfM)photogrammetry,the relationship between the hydraulic characteristic parameters of rill erosion on slopes and microtopographic variation were analyzed.【Result】The results showed that under the experimental conditions,the flow velocity ranged from 0.23 to 0.92 m·s^(-1) and slope had a greater influence on flow velocity than the flow rate.The ranges for the Reynolds number and Froude number were from 255 to 2358 and 1.89 to 5.90,respectively.These hydraulic characteristic parameters increased with an increase in both slope and flow rate(P<0.05),while the resistance coefficient exhibited the opposite trend.Surface roughness,relief amplitude,and surface incision depth varied within the ranges of 0.33 to 2.35 cm,0.47 to 4.35 cm,and 0.53 to 2.53 cm,respectively.The surface roughness,relief amplitude,and surface incision depth were positively correlated with flow velocity,Reynolds number,and Froude number,but negatively correlated with the resistance coefficient.Additionally,surface roughness,relief amplitude,and surface incision depth increased in linear and power function trends with increasing flow velocity and Reynolds number.【Conclusion】As the slope and flow rate increased,all hydraulic characteristic parameters and microtopography factors of the eroded,except for the resistance coefficient,showed a significant increasing trend,indicating that the microtopography was evolving towards conditions that favored erosion.The surface roughness,relief amplitude,and surface incision depth showed a significant positive correlation with changes in flow velocity and Reynolds number.Additionally,the responses of these three microtopographic factors to changes in flow velocity and Reynolds number followed linear and power function relationships.When the flow was low,the variation in surface roughness was the greatest.As the flow rate increased,both the surface relief and the surface incision depth gradually increased,indicating that the downcutting effect of runoff during the erosion process was intense,leading to a continuous increase in rill erosion depth.Our research results can provide a theoretical basis for the control of soil and water loss in loess slope cultivated land and the study of regional ecological restoration.
作者
谭青芳
陈峰庭
黄钰涵
赵明全
常志勇
吴嫡
余新晓
黄子轩
韦娟
TAN Qingfang;CHEN Fengting;HUANG Yuhan;ZHAO Mingquan;CHANG Zhiyong;WU Di;Yu Xinxiao;HUANG Zixuan;WEI Juan(Guangxi Key Laboratory of Forest Ecology and Conservation,College of Forestry,Guangxi University,Nanning 530004,China;School of Soil and Water Conservation,Key Laboratory of State Forestry and Grassland Administration on Soil and Water Conservation,Beijing Forestry University,Beijing 100083,China;Guangxi Vocational College of Water Resources and Electric Power,Nanning 530023,China)
出处
《土壤学报》
北大核心
2025年第4期946-957,共12页
Acta Pedologica Sinica
基金
中国博士后科学基金项目(2022M710404)
国家自然科学基金项目(42207389)
广西研究生教育创新计划资助项目(YCSW2024063)共同资助。
关键词
细沟侵蚀
水力学特性
饱和
地表糙度
地表切割深度
Rill erosion
Hydraulic characteristics
Saturation
Surface roughness
Surface incision depth
