Overland Flow Sediment Carrying Capacity Calculation Method

Overland flow carrying capacity refers to the slope surface flow under certain boundary conditions can be carried by including bed load and suspended load,maximum sediment.Surface runoff flows along the slope after the formation of happening in the process of separation,transport and deposition process of sediment particles,and the carrying capacity of overland flow is identifying whether sediment particle separation,transport and deposition of important basis.Important control factor of soil erosion model is the sediment-carrying capacity of slope surface flow,so the slope surface water carrying capacity to establish suitable for China's actual situation of soil erosion process model has important theoretical significance,and also provide an important scientfic basis for taking soil and water conservation measures and controlling soil and water loss on loess hillslope.Overland flow on flume experiment is to study the sediment-carrying capacity of water dynamics mechanism of the main research methods.In this article,through indoor simulation experiment,studying three slope(6°?9°?12°)and seven discharge(0.0417 L/s,0.083 L/s,0.125 L/s,0.167 L/s,0.208 L/s,0.250 L/s,and 0.333 L/s)combined scouring slope water comprehensive mechanical properties;other scholars test data analysis a total of 355 groups.The overland flow sediment carrying capacity and average flow velocity,shear stress,stream power,unit stream power,the coupling relationship between the effective stream power hydraulic parameters;finally,based on the effective stream power after correction The rate of the establishment of a unified formula.The main conclusions are as follows:The analysis of the test data available: overland flow sediment transport capacity with the increase of slope exponentially increases with the increase of flow rate is exponentially increased.And under different conditions,the influence of the slope and the flow sediment transport capacity of overland flow in different grade is small,the impact of traffic is greater than the slope on the influence of sediment carrying capacity and with the increase of slope,the impact of traffic impact gradually close to the slope of the overland flow;sediment carrying capacity increases with flow depth approximately exponentially increase,in the case of relatively large slope,a small increase in water depth will lead to increase the capacity of overland flow with large amplitude and average velocity of overland flow sediment;a power capacity Function relation,sediment transport capacity increases with the increase of flow rate.In order to eliminate the influence of dimensionless sediment carrying capacity,are dimensionless hydrodynamic parameters and sediment carrying capacity.Based on the experiment,combined with the test data of other scholars,a total of 355 groups were analyzed by regression analysis shows that different particle size,flow and slope,overland flow sediment carrying capacity of average flow velocity.Flow shear stress,flow power,unit flow power,response relationship between the effective stream power hydraulic parameters can be described by exponential equation.Clarified the rill flow sediment dynamics mechanism of the ability to change.Rill flow sediment ability on the decision of the main hydrodynamic parameter response coefficient sequence is: the effective stream power(R2 = 0.9785)> stream power(R2 = 0.9701)> shear stress(R2 = 0.9662)> unit stream power(R2 = 0.8770)> average flow velocity(R2 = 0.8428).Test condition,the effective stream power is with the change of slope surface water carrying capacity most closely the hydrodynamics of indicators,describes the slope flow sediment ability to change the best kinetic parameters.Select the effective stream power was used to simulate the hydrodynamic parameters of sediment carrying capacity,and on the basis of size coefficient correction finally corrected effective stream power is established based on the overland flow sediment carrying capacity from the unified model:?=0.3184h*0.876Sv0.612Weff*0.504.The dimensionless sediment carrying capacity and the dimensionless water depth equation of overland flow volume,sediment concentration,no significant correlation between the dimensionless effective stream power(R2=0.992).