Field Test on Consolidation of Hydraulically Filled Sludge via Vertical Gradient Electro-osmotic Dewatering

An E-tube system to provide vertical gradient electro-osmosis and better vacuum condition in deep soft ground is presented. Consolidation effect was improved in two ways: upward water flow generated by vertical gradient electro-osmosis and improvement of vacuum condition by gathering water in E-tube. Field test was carried out to verify the proposed method. Test result shows that after consolidation, water content decreased from 80 ~ 95% to 44 ~ 59% and dry density increased from 0.76 ~ 0.85 g/cm 3 to 0.95 ~ 1.23 g/cm 3 ; shear strength increased from 1 ~ 2 kPa to 16 kPa and bearing capacity increased from 10 ~ 20 kPa to about 70 kPa. Energy consumption in this field test was 30.5 kW·h/m 3 . This indicates that SCR is not an energy efficient way to build electro-osmosis DC power source. High frequency switch-mode DC power source with PFC might be a better choice.