【摘要】 本文通过水槽试验,研究了细颗粒（粘土类细颗粒）含量对粗颗粒含沙量分布及挟沙能力的的影响。粘土类泥浆具有宾汉流体的特性,其宾汉切应力及刚度系数随细颗粒含沙量S_F的增大而急剧增大。粘性增大使得粗颗粒在其中的沉速大幅度减小,水流中粗颗粒含沙量沿垂线分布趋于均匀,但仍符合扩散理论,即在双对数纸上呈一直线。根据颗粒在宾汉体中下沉的C_D-Re₁关系可以推求粗颗粒在泥浆中的沉速W。而由实测粗颗粒含沙量的垂线分布也可以反算沉速,两者是一致的。S_F极高时流动呈层流流态,粗颗粒含沙量沿垂线均匀分布。粘土泥浆中粗颗粒沉速的减小也有助于粗颗粒的输送。细颗粒含沙量愈大,同样水流强度条件下粗颗粒的输沙率愈高。如果水流强度参数中的沉速采用C_D-Re₁关系推求,则不同细颗粒含沙量泥浆输送粗颗粒的挟沙能力关系可以统一起来。细颗粒含沙量极高的挟沙能力有待进一步研究。更多还原

【Abstract】 The effect of fine particles on the vertical concentration distribution and transport rate of coarse particles is studied by means of a series of flume experiments. Clay slurry behaves as Bingham fluid. Its yield stress and rigidity rapidly increase with the fine paritcle concentration SF. The increase of viscosity makes coarse particles settle much slower. As a result, the vertical concentration distribution of coarse particles becomes more uniform,but it still obeys the law of diffusion theory with a smaller fall velocity W. The fall velocity W of coarse particle can be ascertained by friction factor CD-Reynolds number Re1 correlationship for particle settling in Bingham fluid, and can also be determined according to the vertical concentration distribution of coarse particle. They coincide with, each other. The flow turns to be laminar when SF is extremely high. Under such condition the vertical concentration distribution of coarse particles is uniform. The decrease of fall velocity of coarse particle favors the transport of coarse particles. At same flow intensity the transport rate of coarse particles increases by dozen percent to nearly hundred times with SF increasing. The coarse sediment carrying capacity relationship can be established provided the fall velocity in Bingham fluid is ascertained by the CD-Re1 curve.Further research on sediment carrying capacity at extremely high concentration of fine particle is needed.更多还原