Effects of electrodes configurated vertically on dewatering soft Bangkok clay using electrokinetic

Abstract

This research conducted a series of experiments to evaluate the effectiveness of electrokinetic techniques for water drainage and settlement in soft clay under two electrode configurations: (1) anode at the top and cathode at the bottom (1AT), and (2) anode at the bottom and cathode at the top (1AB). Results from this study show that the 1AB configuration produced greater settlement (27.08 mm, approximately 27% of soil thickness) than the 1AT configuration (21.28 mm, approximately 21%). This is attributed to the combined effects of electrophoresis and gravity, which accelerate settlement when the anode is placed at the bottom. In contrast, the 1AT configuration caused internal cracking due to upward particle movement induced by electrophoresis, opposing settlement. Stiffening of the upper soil layer further reduced the settlement rate. This study also confirms that soil dewatering is governed by electro-osmosis process rather than effect of temperature. Reduction of water content during the experiment affects the efficiency of electrokinetic technique, including electric current and electrical resistance. Therefore, electrokinetic techniques are more suitable for short-term applications, as they can rapidly enhance drainage and settlement during the initial stage, after which the process slows and stabilizes.