A novel electroosmotic chemical treatment technique for soil improvement

Previous studies have shown that injection of chemical solutions through the anode or cathode during electroosmosis is effective in strengthening soft clay. However, the region of improvement is mostly limited to the anode or cathode region. A novel technique of installing a relay pipe between the anode and the cathode was developed to expand the region of electroosmotic improvement. The natural Taipei silty clay, containing 12% clay, 86% silt and 2% sand, was used in this study. Results of this study found that electroosmosis with injection through the relay pipe was superior to that with injection through the anode, nearly 1.5 times in terms of cementation area and 2 times in terms of average cone resistance. With injection through both the anode and the relay pipe, the cementation area nearly covered the entire specimen and its average cone resistance could be raised to nine times more than that of the untreated soil. Moreover, for injection through both the anode and the relay pipe, the increase of injection times of the sodium silicate solution had a better improvement effect, compared with the increase of injection times of the calcium chloride solution. ► The soil improvement can be enhanced by the technique of installing a relay pipe. ► The improvement region can be covered the entire sample by technique of relay pipe. ► The increase of injection times of the sodium silicate had a better improvement.