Study On Sediment Transport Capacity Of Slope Runoff Based On Erosion Energy

Under the action of overland flow erosion,the soil in the Loess Plateau is broken,stripped,transported and deposited in a series of processes,and finally forms a special topography with thousands of gullies and fragmentations.At the same time,it also produces land degradation and farmland destruction;rivers and lakes are silted up,which aggravates flood disaster;worsens the living environment,aggravates poverty and other soil erosion hazards.In order to achieve accurate prediction and prediction of sediment transport process on the slope surface,this paper studies the hydrodynamic characteristics of the slope surface under the coupling effect of different soil texture and sediment concentration through the indoor fixed bed experiment in Gaza.Based on the dimensionless flow intensity parameters,different soil sediment transport capacity and the unified flow intensity parameters,a sediment transport capacity calculation model is established.The main conclusions are as follows:(1)The parameters characterizing the hydrodynamic characteristics of sediment-laden flow,such as flow pattern,mean flow velocity,flow depth and drag coefficient,are affected not only by sediment content,but also by energy slope and flow rate.Except for the flow rate condition Q=0.058L/S,the relationship between sediment content and hydraulic parameters under other flow rate conditions will be zoned due to the change of energy slope.The relationship between sediment concentration and hydraulic parameters at Q=0.226L/S is distinct due to the difference of soil,which is mainly attributed to the critical hydraulic conditions.The resistance coefficient of slope flow is not only dependent on the strength of flow,but also closely related to soil properties.Therefore,the resistance coefficient formula(R~2=0.942)was obtained by combining the two factors.(2)The relationship between sediment transport capacity,energy gradients,and unit flow discharge rates.The sediment transport capacity increased with increasing energy gradient and unit flow discharge,and the unit flow discharge had a more significant influence on sediment transport capacity compared with energy gradient.We used each composite force predictor and measured the sediment transport capacity according to the nondimensional principle,and the resulting data corresponded to different soils distributed in zones,as sediment transport capacity is controlled by a critical starting condition.After including soil clay particle content and volume sediment content in our formula,we were able to derive an accurate equation for calculating sediment transport.Among the dimensionless composite force predictors,the dimensionless effective stream power was the most reliable predictor.The sediment transport capacity and effective stream power were related exponentially.(3)Select more data to study the relationship between general flow intensity index and sediment transport capacity.Based on the research of general flow intensity index and sediment transport capacity,find out the common parameters that constitute each flow intensity index.By combining these parameters,we can get a unified flow intensity index.Because the process of sediment transport depends on the mutual feed of sediment and water energy,based on the unified flow intensity index,considering the comprehensive characteristics of sediment,and then introducing the sediment transport coefficient,a sediment transport capacity model based on the unified flow intensity index is established.