非均匀沙推移质输沙率的研究

本文根据拜格诺水流功率理论,推求出均匀抄和非均匀抄推移质输沙率公式。其中均匀沙公式结构形式与恩格隆公式完全一致,非均匀沙输沙率考虑到粗、细沙的相互影响,用隐暴系数加以校正,隐暴系数可从清水冲刷水糟试验资料反求,结果与林泰造公式非常吻合。用隐暴系数对盖斯勒起动机率进行修正,可以获得非均匀沙粗化的极限级配及粒径计算公式。该级配的平均粒径可以用作非均匀沙起动的判别标准。文中用野外和水槽试验资料对上述公式进行了初步验证,结果均是良好的。

A Study on the Bedload Discharge of Nonunif orm Sediment

In this paper,based on the principle of stream power by Bagnold, the formulae of bedload discharge for uniform and nonuniform sediment were derived. The formation of the formula for uniform sediment is as well as Engelund's formula, and the formula of nonuniform sediment takes account of the interaction of the covering factor for fine particles and the exposing factor for coarse particles in a mixture, which can be obtained from the flume experiment of clear water erosion, The result is in good agreement with Hayashi s formula . By using the factors of coveredness and exposedness to revise the probability of initial motion of sediment by Gessler ,the formulae of grain size distribution for armoring layer can be obtained. Its average grain diameter can be used as a criterion for the initial motion of nonuniform sediment. Preliminary verification shows that above mentioned formulae are satisfied.