高含沙浑水静态剪切应力的试验研究

Experiment study on static yeild stress with hypoconcentration muddy water

以试验为手段对高含沙浑液的静态剪切应力进行了探讨,得出静态剪切应力比用压力式流变仪测出的动态剪切应力要大,其差值随着静态时间的增长而加大,且与含沙量成正比,与粒径成反比的定性结论。配合水槽概化试验,论述了静态剪切应力的存在使高含沙水流层流区的阻力随时间增长而加大;静态剪切应力的存在也是造成河道滩槽贴边淤积和滩地高含沙水流整体停滞的根源,是河槽形成"自然堤"的主要因素。

By the means of experiment this paper probes into the shear stress of the static muddy water. The experiment indicates that the value of the static yield stress is larger than that measured from pressure capillary rheometer and increases with the resting time and the sediment content and is negatively proportion to the particle size. It is learned from the water channel conceptualized experiment that the a static shear stress produces the resistance of the hypoconcentrated laminar flow change with time, and this stress is the root of the globule siltation resulting in the cease of the whole hypoconcentration muddy water flow near boundary of a channel and the root of natural barrier formtion.