Lessons from Case Histories of Electro Osmosis Consolidation

Electro osmotic (EO) ground improvement technique has a promising performance history in improving the properties of fine-grained soils. A review of data from 11 case histories indicates that EO consolidation can strengthen various types of fine-grained soils, from slurries to clayey silt, with initial shear strengths from 1 to 28 kPa. The level of shear strength improvement depends on the ratio of applied electrical potential difference and electrode spacing (V/S). A maximum induced shear strength of up to about 4 times of initial value has been observed with 0.18 < V/S < 0.25 in about 4 days. A maximum improvement depth of 1.4 times the electrode length has been reported. In addition, utilizing electrodes made up of thin metal core, preferably steel covered by electrically conductive geosynthetics, can minimize gas production and potential loss at electrode-soil interfaces and consequently decrease the level of power consumption in EO systems.