Electrokinetic strengthening of a marine sediment using intermittent current

An experimental program on electrokinetic strengthening of a marine sedimen t using intermittent current was conducted on a high-salinity marine clay r ecovered from a land reclamation site on the Korean coast. The study focuse d on the use of electrokinetics to enhance the effect of surcharge preloadi ng consolidation to improve mechanical and physical properties of soil. Thi s paper presents the design, execution, and results of the electrokinetic t ests performed in a custom-designed electrokinetic cell. The test results d emonstrate that electrokinetic treatment combined with preloading consolida tion is an effective method of increasing the shear strength and decreasing the water content of the marine sediment beyond that achievable by preload ing consolidation alone. For the same consolidation pressure over the ident ical time period, the increase in the average undrained shear strength of t he marine sediment after electrokinetic treatment combined with preloading consolidation was up to 145% greater than that achieved by the preloading c onsolidation alone. A corresponding decrease in the soil water content of a pproximately 125% was measured. The power consumption and electrode corrosi on are reduced by using intermittent current. The process developed in this research has potential applications in strengthening soft clayey soils at and around foundations of new onshore and offshore structures embedded in m arine sediments and for rehabilitation of existing offshore platforms.