On the enhancement of electroosmotic soil improvement by the injection of saline solutions

The effect of electroosmosis with injection of saline solutions on a silty clay was studied. A laboratory testing program was performed to assess the probable effectiveness of electroosmosis with the injection of saline solutions. Results indicate that the effect of electroosmosis can be enhanced and the treatment time can be shortened by the injection of saline solutions during electroosmosis. The average undrained shear strength of the soil treated with electroosmosis for 7 days after initial injection of the CaCl2 solution was 5.0 times that of the untreated soil and 1.25 times that with electroosmosis only. The treatment time was also shortened by 40% for the injection of the CaCl2 solution during electroosmosis, compared with electroosmosis only. The quality of electroosmotic improvement could be enhanced by injecting solutions of higher valence, concentration and by applying higher electric potential. However, the improvement was limited to the area near the anode unless the treatment time was increased to ensure that no water was drained from the cathode.