A novel technique of harmonic waves applied electro-osmotic chemical treatment for soil improvement

Previous studies have shown that the application of direct current (DC) during electro-osmosis with injection is effective in strengthening soft clay. However, the DC can be obtained from an alternating current supply by use of a current-switching arrangement called a rectifier and a filter. In this study, a novel technique of using the half wave rectification and full wave rectification (Harmonic waves) during electro-osmosis with injection was developed to expand the different types of power supply and to achieve an economic and practical goal. Owing to the reduction in the filter component for the half wave rectification and full wave rectification, the price of a power supply may be reduced. Results of this study indicate that an effective improvement was observed in the circular experimental cell by using a half wave rectification or full wave rectification on the soil's mechanical properties such as CPT. In particular, the improvement effect by using the full wave rectification is close to that using the rectification and filter in terms of region of improvement and average cone resistance. The confirmative experimental results also show that the improvement in a rectangular experimental cell by using the full wave rectification is close to that using the rectification and filter in terms of region of improvement and average cone resistance. Hence, the technique of the full wave rectification may be economically and practically applied in electro-osmotic chemical treatment for soil improvement.

Research highlights
► An effective soil improvement was observed by using full wave rectification.
► The technique of the full wave rectification may be economical.
► The rectification and filter can be replaced by using full wave rectification.