【摘要】 在非均匀推移质输移机理的基础上,通过理论分析、推导及计算,得到泥沙起动无量刚最小临界切应力参数0θ值为0.02。提出了一种计算推移质输沙率的方法及公式,该公式表明,在水流强度一定时,输沙率并非为一个常量,而是随颗粒在床面的相对暴露度而变。根据平衡输沙时0θ的最小取值,得到平衡输沙时推移质泥沙颗粒最大粒径dcm ax的计算式,在此基础上提出了一种计算推移质级配的方法。验证结果表明计算与实测资料符合较好。更多还原

【Abstract】 A series of concludes have been obtained,through theoretical analysis,formulas derivation and parameters calculation based on analysis of the motion mechanism of non-uniform bed load.The minimum dimensionless critical shear stress value of non-uniform sediment has been obtained as 0.020.The formula for calculating the transport rate of bed load of non-uniform sediment has been proposed.The formula shows the transport rate is not a constant but varies with the relative exposure degree of particles that lying on riverbed when the flow intensity is at fixed value.The condition and formula for calculating the maximum diameter,d_{c max},of incipient sediment according to the minimum dimensionless critical shear stress value,θ₀,of bed load at equilibrium condition has been put forward.And a formula for calculating the size distribution of bed load has been presented too.Results above mentioned have been verified with field or laboratory experimental data.更多还原