Analytical Investigation of Electroosmotic Consolidation in Unsaturated Soils Considering the Coupling Effect and a Nonuniform Initial Water Content

Electroosmosis often dewaters soil into unsaturated conditions. Due to the shrinkage deformation and decrease of effective voltage that occur during the electroosmotic consolidation as the soil changes from the saturated to unsaturated state, an analytical solution with the consideration of the coupled deformation and time-decreasing effective voltage was developed for one-dimensional (1D) electroosmotic consolidation in unsaturated soils. The effect of nonuniform distribution of the initial water content was also considered. To validate the effectiveness of the proposed analytical solution, a laboratory test was conducted. Thereafter, the proposed solution was used in a parametric study to investigate the effects of the coupled deformation, distribution pattern of the initial water content, and decrease rate of the effective voltage. The results indicated that the coupling effect increases with a decrease in the desaturation coefficient, and the coupling effect is significant for soft soils with high retention capability and compressibility. The nonuniform distribution of initial water content also had a great influence on the consolidation rate. When the initial water content increased from the anode to the cathode, the consolidation rate was fast in that direction but slow in the other direction. Finally, with the consideration of time-decreasing effective voltage, the calculated maximum matric suction and drainage decreased and the completion time of electroosmotic consolidation was shortened. In summary, the analytical solution developed in this study could capture the actual problems for electroosmosis consolidation in field applications to some extent.

Automated summary

The analytical solution developed in this study considers coupled deformation and decreasing effective voltage in one-dimensional unsaturated soil due to electroosmosis. Laboratory tests and parametric studies show an increase in coupling effect, the influence of initial water content distribution on consolidation rate, and a shortened completion time of electroosmotic consolidation with decreasing effective voltage over time.