Electrokinetic strengthening of soft clay

Abstract

The use of electrokinetic treatment to decrease the water content and increase the shear strength, preconsolidation pressure and axial load capacity of a laboratory-prepared soft clay soil was investigated. The tests were carried out in four identical electrokinetic cells. The cell has a volume capacity of 10 litres. A DC voltage of 10 V was applied in the tests investigating the water content, shear strength and preconsolidation pressure. A DC voltage of 5 V was used in the tests investigating the axial load capacity. The energy consumption for each test was 54 W h. The electrokinetic treatment decreased the water content across most of the cell with the lowest water content near the anode (32·8 ± 2% in comparison with 52·7 ± 2·7% in the control) and increased the undrained shear strength across the cell with the highest shear strength reported near the anode (62·5 ± 6·2 kPa in comparison with 6·3 ± 2·1 kPa in the control). Electrokinetic treatment increased the preconsolidation pressure across the cell with the maximum pseudo-preconsolidation pressure near the anode (91 kPa in comparison with pre-loaded surcharge pressure of 10 kPa). The axial load capacity of the foundation model after the treatment was 156 N when the foundation model was serving as the anode and 173 N when the model was not used as an electrode. The loss in the mass of the foundation model by corrosion was 4·7% for the former and 0·4% for the latter.