Abstract
The main purpose of this experimental study is the estimation of critical shear stress of cohesive bottom sediments. The resistance properties against currents are mainly controlled by the electro-chemical bond between individual particles. Hydraulic experiment and physico-chemical test were performed. Bottom sediments were divided into two groups according to characteristics of settling form, flow curve and resuspension behavior. The main factor which controls those characteristics was found to be the nature of cations adhering to particle's surface. For bottom sediments two critical shear stresses were defined from the resuspension behaviors. They showed linear relation with respect to viscosity and yield value on log-log paper but the relations were different between two groups.
