Effect of electrode material on electro-osmotic consolidation of bentonite

Abstract

Electrode material has significant influence on the behavior of soil during electro-osmotic consolidation. Four electro-osmotic consolidation experiments on a sodium bentonite were conducted with copper, iron, graphite and stainless steel electrodes. The result indicated that the copper electrodes achieved the best drainage performance. The change in drainage rate, current and voltage loss near the anode was similar for the four electrodes, with a rapid change stage in the first 2 hours followed by a slow change stage in the next 6∼8 hours and finally a stable stage. The rapid voltage loss in stage 1 was mainly caused by the formation of vertical and horizontal cracks, while in stage 2, the relative less voltage loss was due to the corrosion of electrode and the development of cracks. The electro-osmosis conductivity decreased along with the drainage of water and varied in the range of 1×10-4 to 1×10-5 cm2/ (V?s). The average electro-osmosis conductivity and the average energy consumption per milliliter water discharge were independent of electrode material.