Effect of anode condition on electro-osmotic consolidation combined with vacuum preloading

Electro-osmotic consolidation combined with vacuum preloading is a potential technology to dewater the soft soils and slurry. The anode condition has a significant effect on dewatering efficiency during operation, which is not adequately addressed. In this study, laboratory tests were conducted to study the effect of different boundary conditions of anode on the soil-improvement result using the combination of electro-osmotic consolidation and vacuum preloading, then to obtain the best combination mode. During the physical modeling tests, the soil mass was treated by vacuum preloading first and then further processed by the combined method. Three model tests were conducted to study the effect of different vacuum conditions on electrode, while CaCl2 solutions were injected at the anode in another two tests to study the effect of the electro-osmotic chemical treatment. The discharge of water and electrical current were measured during the tests, and the soil strength were measured after the implementation of the tests. The results indicated that the combined method was more effective to remove pore water from the soil mass compared with the traditional vacuum preloading. Although the vacuum preloading and electro-osmosis drove the water flow in the opposite direction near the anode, the vacuum pressure applied on the anode prevented the soil cracks, which increased electrical current obviously and removed 15% more pore water. The injection of CaCl2 solution at the anode showed slight effect on dewatering process, however, the bearing capacity was increased significantly.

Automated summary

The study found that the combination of electro-osmotic consolidation and vacuum preloading is more effective in dewatering soft soils and slurry compared to traditional vacuum preloading. The application of proper vacuum pressure can prevent soil cracking, increase electrical current output, and improve dewatering efficiency.