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为澄清复杂地表的水流运动过程、水流水力学参数受流量及地表状况的影响,该研究采用野外标准径流小区实地放水冲刷试验,研究了鱼鳞坑、苜蓿草地、秸秆覆盖不同径流调控措施的坡面薄层水流水动力学特性的变化规律,包括水流流速、水深、流态、阻力系数。研究结果表明:坡面薄层水流的平均流速与水深主要受流量控制,其二者之间呈现幂函数关系;地表状况与流量大小直接影响着坡面流态,对于裸地与鱼鳞坑坡面,流量较小时属于层流与缓流,在流量达到3.0m3/h时,属于过渡流、紊流和急流;而苜蓿草地、秸秆覆盖坡面均属于层流和缓流;并提出复杂坡面的阻力系数由颗粒阻力、形态阻力、波阻力叠加而成,其大小主要受地表状况影响;阻力系数与土壤侵蚀率呈现良好对数关系。总之,坡面采取径流调控措施后,其地表抗侵蚀力和泥沙搬运的能力明显强于裸地,径流流速明显降低,水流流态明显平缓,水流受阻力显著增加。研究结果对于揭示不同径流调控措施对坡面拦泥蓄水、减流减沙及侵蚀动力学机制有着重要的理论基础和实践指导意义。
In order to clarify the water surface movement process of complex surface, the hydraulic parameters of the hydraulic flow are affected by the flow and the surface conditions. In this study, field standard runoff plots were used to scour the groundwater in the field. The effects of different scaling measures such as scale pit, alfalfa grassland, The variation regularity of hydrodynamics of thin-layer water includes the velocity of flow, water depth, fluid state and resistance coefficient. The results show that the average flow velocity and water depth of the laminar flow on the slope are mainly controlled by the flow rate, which shows a power function relationship between the two. The surface conditions and the flow rate directly affect the flow regime on the slope, , When the flow rate is small, it belongs to laminar flow and slow flow. When flow rate reaches 3.0m3 / h, it belongs to transitional flow, turbulent flow and rapids. However, alfalfa grassland and straw mulching slope belong to laminar and slow flow; The drag coefficient is composed of particle resistance, form resistance and wave resistance. The size of the drag coefficient is mainly affected by the surface condition. The drag coefficient shows a good logarithm relationship with the soil erosion rate. In short, the surface runoff regulation and control measures, the surface erosion resistance and sediment handling capacity was significantly stronger than the bare land, runoff velocity decreased significantly, water flow was significantly flat, the water flow resistance increased significantly. The results of this study have important theoretical basis and practical guiding significance for revealing different runoff regulation measures on the sediment storage, runoff and sediment reduction and erosion kinetics of the slope.