Abstract: Study on the flocculation mechanism of cohesive sediment is of great significance to the treatment of deposition in estuaries, reservoirs and waterways and water environment protection. In this paper, we made a review on the equipment and methods used in numerical simulation, field observation and laboratory experiment of cohesive sediment flocculation, and also expounded the research achievements of sediment flocculation under the influences of turbulent shear rate, salinity, suspended sediment concentration and organic matters. Researches in the following fields are still inadequate: three-dimensional observation of floc structure, in-situ observation of flocculation in high-concentration water, sediment flocculation influenced by multi-factor, and the quantitative relation between flow turbulence structure and flocculation characteristics. Researches need to be strengthened in the following aspects: developing flocculation observation device; quantifying the corresponding relation between flow turbulence structure and flocculation characteristics; multi-factor coupling experiment; and three-dimensional structure observation of floc.

Key words: cohesive sediment, flocculation devices, experimental methods, influencing factors, mechanisms of flocculation