THE IMPACT OF SILT CONTENT ON THE FLOCCULATION PROCESS OF CLAY-SILT MIXTURES

Flocculation of natural mud has a great potential to alter flocs with sizes, densities, and shapes (and thus settling velocity) that are vastly different from original constitutive primary particles, which will further influence sediment transport processes, including floc deposition or settling, sediment consolidation or perturbation, and erosion or initiation. It has been acknowledged that the turbulent shear effect and sediment concentration are the main factors influencing the flocculation processes in energetic environments such as coastal regions and estuaries by increasing or decreasing the collision frequency or efficiency of particles. As natural environments contain suspended sediment of both cohesive sediment and non- cohesive sediment, which makes the flocculation processes more complex. Though the flocculation behaviors on mud–sand mixtures have been extensively investigated, few efforts have been made to assess in detail the impact of clay–silt interactions on the properties of flocs formed. Therefore, in this study, a series of experiments were conducted to investigate how silt (its presence and content; changes in composition) influences floc properties under equilibrium turbulent shear conditions.