摘要
细沟侵蚀是黄土坡面最主要的侵蚀方式之一,土壤剥离过程是细沟侵蚀中的重要环节。采用6种坡度(2°、4°、6°、8°、10°、12°)、5种流量(8、16、24、32、40 L/min)组合冲刷试验,系统研究了黄土坡面细沟流土壤剥蚀率与水动力学和床面形态的耦合关系。结果表明:土壤剥蚀率与流量、坡度均呈幂函数增加关系,且坡度对土壤剥蚀率的影响更大;不同类型土壤无量纲剥蚀率与无量纲流速之间存在分区现象,表明土壤侵蚀受到除泥沙粒径外其他因素的影响;不同类型土壤无量纲剥蚀率与无量纲切应力双对数函数呈线性增加关系,且不存在分区;不同类型土壤无量纲剥蚀率与无量纲单位水流功率存在分区;土壤剥蚀率随跌坑发育系数的增加呈幂函数增加趋势,而土壤剥蚀率随L/H增加呈幂函数减小趋势,说明床面形态越加复杂、跌坑发育越加成熟,土壤侵蚀就越剧烈。研究结果对细沟水流侵蚀机理的探究具有一定的理论价值,对黄土坡面水土流失治理及生态修复均具有一定的指导意义。
Rill erosion is one of the most important slope erosion in loess area, and soil detachment process is an important link of rill erosion. However, the existing studies only are based on a single soil conditions, while the simple relationship between soil detachment rate and water dynamics cannot fully reflect the coupling mechanism of the soil detachment rate under different types of soil. More importantly, the existing research involves little on the relationship between the detachment rate and bed surface morphology. The article adopted the combination of six kinds of slope gradients （2°, 4°, 6°, 8°, 10° and 12°） and five discharges （8 L/min, 16 L/rain, 24 L/min, 32 L/min, 40 L/min） to do scouring experiment. The results showed that： soil detachment rate had power function relationship with discharge and slope, and slope had a greater influence than discharge; Different types of non-dimensional soil detachment rate and non-dimensional unit stream power had zoned phenomenon with non-dimensional flow velocity which showed that soil detachment had other influence factors except diameter of particles; Non- dimensional soil detachment rate and non-dimensional shear stress double-log function had a linear increase relationship, and there was no partition; Soil detachment rate had a trend of increase power funetion with Ihe increase of down hole development coefficient, and the soil detachment rate had a power function decreasing trend with the L/H increases. This resuhs show that the more complex bed surface morphology increased, the more mature down hole developed increasingly and the more intense soil detachment is. The results of the study have some theoretical value to the mechanism of sediment transport on rill flow erosion, moreover it has a certain guiding significance on loess slope surface soil detachment control and ecological restoration.
出处
《农业机械学报》
EI
CAS
CSCD
北大核心
2016年第9期134-140,共7页
Transactions of the Chinese Society for Agricultural Machinery
基金
国家自然科学基金项目(51579214)
中央高校基本科研业务费专项资金项目(Z109021564)
黄土高原土壤侵蚀与旱地农业国家重点实验室主任基金项目(A314021402-1619)
流域水循环模拟与调控国家重点实验室开放基金项目(IWHR-SKL-2014)
