Author(s): Zhaoyin Wang; Peter Larsen; Wei Xiang

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Keywords: Rheology; Clay suspension; Yield stress; Thixotropy; Mineral composition; Cations; Superelevation; Hyperconcentrated flow; Stagnant layer

Abstract: The rheological properties of sediment suspensions were investigated. The suspension of fine sediment exhibited yield stress but the suspension of coarse sediment did not. The difference was mainly because of their different mineral composition rather than diameter. Some clay suspensions exhibited thixotropy. therefore, the minimum head to siphon the suspensions after agitation was considerably smaller. to thixotropy, rheopexy or antithixotropy was observed for some clay suspensions. In hyperconcentrated flows, a phenomenon so called “stagnant layer” occurs. sometimes, which is attributed to the rheopectic characteristics. Cations had considerable effect on the rheological properties. At low clay concentrations clay suspension with Na+ exhibited higher yield stress than those with Ca+ and Mg++. At high clay concentrations, however, clay, suspensions with divalent cation had much larger yield stress and rigidity coefficient than those with monovalent cations. Hypenconcentrated clay suspension exhibited normal stres, too. The superelevation, when clay mud flowed through a bend, was much larger than the superelevation of water flow.

DOI: https://doi.org/10.1080/00221686.1994.9728352

Year: 1994