Analytical Solution for Vacuum Electroosmosis Consolidation Considering Nonlinear Attenuation of Electric Permeability Coefficient of Copper-Contaminated Sediment

Abstract

Conventional vacuum electroosmosis consolidation theory tends to assume that the electric permeability coefficient remains unchanged or attenuates linearly. In contrast, the sediment from environmental dredging projects contains copper contaminants, whose electrochemical reactions during electroosmosis may influence the soil properties. Consequently, electroosmosis experiments were conducted for copper-contaminated sediments. It was found that the electric permeability coefficient attenuated rapidly due to the generation of copper hydroxide flocculant deposits under electrochemical reactions. The attenuation was 67.89% after 48 h, and its attenuation trend had obvious nonlinear characteristics. On this basis, an expression for the attenuation of the electric permeability coefficient with time was obtained by fitting an exponential function. A two-dimensional vacuum electroosmosis consolidation model considering the nonlinear attenuation rule of the electric permeability coefficient was established, and the analytical solution of the pore water pressure was deduced. Vacuum electroosmosis experiments on contaminated sediment were carried out, and the measurement results of pore water pressure at the anode verified the rationality of the analytical solution. It was also compared with conventional vacuum electroosmosis consolidation theory, which showed that the analytical solution in this study is better able to predict the dissipation of pore water pressure during long-term vacuum electroosmosis.