Soil improvement using electroosmosis with the injection of chemical solutions: field tests

Previous laboratory studies have shown that the injection of a calcium chloride solution followed by the injection of a sodium silicate solution during electroosmosis is effective in strengthening soft silty clay. Very stiff cemented soil near the anodes is formed after the treatment. This paper presents the effectiveness of the process in the field. Nine electrodes were installed using two grid arrangements with electrode spacings of 2.0 m x 2.5 m and 2.0 m x 5.0 m. The test procedure is similar to those employed in the laboratory. Test results show that the soil surrounding the anodes (within a diameter of 50-60 cm) became very stiff and cemented due to the effect of cementation between the two chemical solutions and soil particles under the electric field. Except for the areas of stiff cemented soil, the undrained shear strength of the soil between electrodes was increased substantially. Polarity reversal after normal polarity did not produce favorable improvement effects in terms of undrained shear strength of the soil and treatment time.