Abstract: In order to study the effect of electro-osmotic drainage on soil properties, electro-osmotic consolidation of the muddy soil in
a river channel in Nanjing was studied in laboratory by using wire electrode in a model. Before and after electro-osmosis, the muddy
soil was analyzed and compared through physical and mechanical properties. The results demonstrated that liquid limit, plastic limit
and the plastic limit index decreased after electro-osmosis. Before and after the electro-osmosis, the soil was used for direct shear test
under the same water content and dry density. It’s found that the cohesion and internal friction angle of the soil reduce under specific
conditions, that is, electro-osmosis leads to strength attenuation. In this paper, the mechanism of soil strength attenuation is explained
based on cation loss in soil during electro-osmosis. In addition, this paper proposed a new electro-osmotic mechanism to explain the
phenomenon of soil cracking in the process of electro-osmosis from the microscopic point of view. The anode had the earliest fracture
due to rapid dehydration, but the extension range of fracture was smaller. The water content of cathode was always higher than that of
the anode and cathode had the slower water loss. So, the cathode had a large range of crack extension. It is worth mentioning that，the
influence of the cation loss on the properties of the soil has not been noticed in the past study

Key words: muddy soil, electro-osmosis, comparative study, mechanism, strength attenuation, soil cracking