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

Abstract

The electroosmotic improvement of silty clay using calcium chloride and sodium silicate solutions as injection materials was studied. A series of laboratory tests were performed on reconstituted samples in order to assess the probable effectiveness of electroosmotic treatment with injection. Results indicate that the two injection materials can be effectively introduced into silty clay by electroosmosis. Very stiff cemented soil, approximately 5–6 cm in diameter, surrounding the anode, was formed due to cementation reactions between the two injection materials and soil particles under the electric field. It is justified to assume that pozzolanic reactions were responsible for the formation of very stiff cemented soil. In addition to the area of very stiff cemented soil, the region of improvement was also expanded to the cathode, near which the undrained shear strength of soil was increased by an average of approximately 195%. It was also found that the technique of polarity reversal was unnecessary for the employment of calcium chloride and sodium silicate solutions as injection materials.