IMPROVEMENT OF SOFT CLAYS BY HIGH-VOLTAGE ELECTROKINETICS

The theory of high-voltage electrokinetics in clay-water-electrolyte s ystems was developed. Upon application of a nonuniform high-voltage di rect-current (DC) field to a clay-water-electrolyte system through ele ctrically insulated electrodes, electrophoretic and dielectrophoretic forces are generated and imposed on clay particles. The former are ind uced by the interaction of a DC field with negatively charged clay par ticles, whereas the latter are induced by the interaction of the elect rical diffuse double layer in a nonuniform electric field. The effects of high-voltage electric fields to the properties of a disturbed mari ne sediment were investigated in an experimental program. The primary experimental data indicate that high-voltage electrokinetics increased undrained shear strength of a marine sediment up to 267% and the pull out resistance of steel plates up to 88%. The effect of high-voltage e lectrokinetics was irreversible even long after withdrawal of the elec tric fields. The treatment was energy efficient and had minimal electr ochemical reactions due to insulation of the electrodes.