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使用天然尺度的实验室渠道观测了在恒定流条件下非均匀卵石床面的推移质运动变化过程,采集到了高精度、长时间序列的输沙率变化过程,用Γ分布有效描述了推移质输沙率的随机过程。在采样历时较短时,规则明渠的单宽输沙率过程与单宽输沙率横向分布均呈现较大的随机性,但随着采样历时的延长,虽然规则明渠的单宽输沙率过程仍呈现一定的随机性,但规则明渠的单宽输沙率的横向分布基本趋于稳定。相对推移质单宽输沙率概率密度分布可近似地表示为Γ分布,且α、β的取值随采样历时与无量纲希尔兹切应力的增大而增大。利用本次试验成果,通过多元线性回归,得到了α、β与采样历时以及无量纲希尔兹切应力的关系式,可为工程应用提供参考。
The natural scale laboratory channel was used to observe the change of bedrock mass movement in the non-uniform pebble bed under the condition of constant flow. The high-accuracy and long-time sediment change rate was collected. The Γ distribution was used to describe the mass transfer Sand rate of random process. When the sampling duration is short, the single-width sediment transport rate and the single-width sediment transport rate show a large randomness in the regular open channel. However, with the prolongation of the sampling duration, although the single-wide sediment transport rate It still shows a certain degree of randomness, but the horizontal distribution of the single-width sediment transport rate of the regular open channel has basically stabilized. The probability density distribution of wide-rate sediment transport rate can be approximately expressed as Γ distribution, and the values of α and β increase with the increase of sampling duration and dimensionless Shielditz stress. Based on the results of this experiment, the relationship between α, β and sampling duration and the dimensionless Shields stress was obtained by multivariate linear regression, which can provide reference for engineering application.