Abstract: The changes of electricity current, water discharge, interfacial resistance and final shear strength after CaCl₂ solution was added to electrodes during the electro-osmosis of kaolin clay were studied through laboratory test. Results show that adding CaCl₂ solution to the electrodes could effectively control the decrease of current in soil, and the current strength is not only related to the amount of added CaCl₂ solution, but probably also to the proportion of CaCl₂ solution added to the anode, or the time when the CaCl₂ solution is added. Displacement becomes larger, improving by 10.9% under the condition of the present experiment. The decrease of interfacial resistance of anode is obvious. The total resistivity of the kaolin soil declines obviously with the resistivity decline of the soil near cathode making the main contribution. Moreover, the average shear strength near anode and in the middle of the soil increases obviously, especially the average shear strength near anode of the soil increases by 16.4 kPa; whereas the average shear strength of the soil near the cathode does not increase. Therefore, reversing the electrodes could be an approach of electro-osmosis test on kaolin soil near the cathode.

Key words: kaolin clay, electro-osmosis, electrodes, CaCl2 solution, resistivity of soil, interfacial resistance, shear strength