Abstract: Electroosmotic reinforcement of low-permeability soft clay is one effective soft soil foundation reinforcement technique. However, excessive power consumption and uneven reinforcement effect limit its application. Chemical electroosmosis is an advanced technique which can improve the uniformity of the treated soft ground and reduce the electroosmosis time and power consumption by injecting sodium silicate (Na2SiO3) and calcium chloride (CaCl2) solutions in the late stage of electroosmosis. Model tests on chemical electroosmosis of soft ground were carried out. The overall water discharge and drainage rate during electroosmosis and chemical electroosmosis processes were measured. The energy consumption factors (such as, soil sample resistance, current, etc.) and reinforcement effects (such as, water content, soil sample strength, etc.) influenced by injection positions were analyzed in detail. Combined with scanning electron microscope (SEM) and inductively coupled plasma-mass spectrometry (ICP-MS), the microscopic mechanisms of reinforced soil sample were discussed. The results show that the relative optimal way of chemical electroosmosis is that CaCl2 solution and Na2SiO3 solution are injected simultaneously into the anode and middle of the soil sample. Compared with traditional electroosmosis method, the water discharge of chemical electroosmosis increases 25.5%, and the shear strength value increases 168.8% under the experimental conditions. The disadvantages of traditional electroosmosis such as uneven water content of the anode and cathode soil after drainage can be improved.

Key words: ground improvement, chemical electroosmosis, soft clay, injection position, model test