中文摘要：

提出了水量百分数这一非均匀沙不平衡输沙的一个重要概念和有效工具。给出了水量百分数定义及其表达式。分析了它的3个特性：它能严格地将均匀沙挟沙能力迭加为非均匀沙挟沙能力；在强平衡条件下，水量百分数恰等于床沙级配；水量百分数就是能量百分数。进而利用水量百分数证明了床沙质、冲泻质与全沙具有相同的挟沙能力；证明了用它可以导出非均匀沙不平衡输沙时的挟沙能力组成以及挟沙能力级配和有效床沙级配表达式。

英文摘要：

The percentage of flow discharge is an important concept and tool proposed by the author to study non-equilibrium transportation of nonuniform sediment. In this paper the definition and expression for the percentog of flow discharge are presented. And then the three characteristics are revealed： the carrying capacity of the nonuniform sediment being able to ex- pressed as the summation of uniform sediment using the percentage, the percentage of flow discharge equaling to size distribution of the bed material, and the percentage being the same as the percentage of energy. Based on the concept of this percentage it is proved that the bed material load, the wash load and the total load follow the same rule of the carrying capacity, and the composition of the carrying capacity and the expressions of size distribution of the carrying capacity and the effective bed material all can be derived.