Rheological experiments on dense silty sediments under steady shear loadings

Abstract

Dense silty sediments exhibit complex rheological behaviors due to their particular sediment composition, which consists of sand, silt and clay. This paper investigated the rheological properties of ten dense silty sediments prepared with various percentages of kaolin. A set of rheological experiments was conducted with an MCR302 rheometer. Measurements of the flow curves, deformation curves, and shear stress-time response were made. The dense silty sediments underwent a solid-liquid transition during shear rate ramp tests, and the critical shear stress increased with decreasing median particle diameter D50. Thixotropy was common in the samples with smaller D50, but the samples with larger D50 displayed anti-thixotropic behavior. Both the power-law model and the Herschel-Bulkley model were selected to describe the rheological behavior, and the Herschel-Bulkley model was more suitable for samples with higher density and smaller D50. The parameters in the empirical expressions for calculating rheological parameters were obtained by a regression analysis.