Electrokinetic settling and sedimentation behavior of cohesive soils in dilute suspension

Abstract

In this study, the electrokinetic (EK) effects on settling behavior of clayey soils under different electrolyte solution, electric field strength, and moisture content were evaluated using kaolin and natural marine clay. A number of laboratory-scale column experiment were carried out in order to examine the effects of electrophoresis and electro-osmosis during settling processes. The settling velocity under different electrolyte solution was found to become faster resulting from the formation of floc due to the contraction of electrical double layer. The electrically induced surface settlement was faster in settling rate and greater in magnitude by comparison with that under the conventional gravitational sedimentation. The effects of electrophoresis on settling behavior become significant from the beginning of hindered settling stage due to the influence of electrochemical interactions between the charged clay particles.

Keywords:

• Clayey soil
• electrolyte
• electrokinetics
• electroosmosis
• electrophoresis
• kaolin
• marine clay
• pH
• sedimentation
• settling behavior
• suspension

Acknowledgments

The research was carried out with partial funding from BK21 (Brain Korea 21), which is greatly appreciated.