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基于实测资料以长江河口南汇潮滩为例,对传统机制分解法进行改进,将机制分解计算中的含沙量项按悬沙粒径进行分组处理,分为63～250、16～63、4～16、0.5～4μm 4个粒径组,对各粒径组泥沙的净输移通量分别进行机制分解计算,分析不同粒径组泥沙的各机制分解项对悬沙净输移通量的贡献。研究表明不同粒级的泥沙其控制输沙的潮滩动力因子不同。相当于粘土类(0.5～3.9μm)和细粉砂类(3.9～16μm)粒级的悬移质泥沙,平均流项T1+T2及潮泵项T3+T4+T5对其输移起控制作用;相当于粗粉砂类(16～62.5μm)和细砂类(62.5～250μm)粒级的悬移质泥沙,潮泵项T3～T5、潮振荡项T6～T8起控制作用。同时,对不同水深条件下同粒级悬沙净输移通量的机制分解项的比较,当悬沙输移过程由深水进入浅水时,潮泵项的贡献急剧减小,且不受大小潮汛、悬沙颗粒粒级粗细的影响。
Based on the measured data, taking the Nanhui tidal flat at the mouth of the Yangtze River as an example, the traditional mechanism decomposition method is improved. The sediment concentration in the mechanism decomposition calculation is grouped according to the particle size of suspended sediment, and divided into 63 ~ 250, 16 ~ 63, ~ 16, 0.5 ~ 4μm. The net transport flux of sediment in each particle size group was decomposed and calculated by mechanics. The mechanism of each mechanism of sediment transport in different particle size groups was analyzed. Contributions. The research shows that the sediment driving force of sand transport with different grain sizes is different. Which is equivalent to suspended sediment of clay grade (0.5-3.9μm) and fine silt (3.9-16μm). The average flow term T1 + T2 and tidal pump term T3 + T4 + T5 control the transport of sediment , Which is equivalent to the suspended sediment of the coarse silt (16 ~ 62.5μm) and fine sand (62.5 ~ 250μm) particles. The tide pump term T3 ~ T5 and the tidal oscillation term T6 ~ T8 play a controlling role. At the same time, compared with the mechanistic decomposition of the net fluxes of suspended sediment under different water depths, when the process of suspended sediment transport from deepwater into shallow water, the contribution of tidal pumping items decreases drastically and is not affected by tidal floods , Suspended sediment particle size effect.