Abstract: In order to solve the problems of low drainage efficiency and uneven consolidation effect of muddy soil during traditional electro-osmotic drainage process, a new idea of using anionic polyacrylamide (APAM) combined with electro-osmosis method to treat muddy soil was developed from the perspective of changing the water holding characteristics of soft clay particles. The self-made one-dimensional electro-osmotic consolidation test device was used to explore the mechanism of flocculation- electroosmosis method and the influence of different mixing ratios of flocculant on the reinforcement effect. The results show that APAM reduces the thickness of the bound water film on surface on soft clay particles as compared with the traditional electroosmosis method, significantly improves the early electroosmotic drainage rate and cumulative drainage of muddy soil, thus lowering the average energy consumption coefficient of electro-osmotic method. Meanwhile, the “adsorption bridging” effect of the macromolecule long chain of flocculant enhances the cohesive force and flocculation deposition effect of soil particles, which effectively alleviated the cathode clogging caused by the migration and agglomeration of fine clay particles. The shear strength of muddy soil was increased greatly after treatment, and its uniformity was also significantly improved. When the mixing ratio of the flocculant APAM was 0.30%, the highest efficiency of electro-osmotic drainage and the optimal consolidation effect of muddy soil were achieved.

Key words: muddy soil, flocculation, electro-osmosis method, mixing ratio, consolidation effect