A two-dimensional analytical solution for electro-osmotic consolidation in multi-layered soft soils using vertical electrodes

The electro-osmosis technique has been proven to be effective in soft ground improvement. Compared to horizontally arranged electrodes, vertically inserted electrodes into the ground offer significant construction advantages, making them the preferred choice for electro-osmotic consolidation. Ground soils often exhibit stratified characteristics; however, the impact of soil stratification on electro-osmotic consolidation using vertical electrodes remains unclear. This study proposes a novel two-dimensional analytical model for electro-osmotic consolidation in multi-layered soils using vertical electrodes to investigate the impact of soil stratification. The separation of variables method is employed to decouple two spatial variables and one temporal variable, resulting in an exact analytical solution. The model is validated against several benchmark cases. Parametric analyses first highlight the versatility of the proposed model, especially in stratified soils with significant variations in hydraulic permeability. Furthermore, analyses of typical three-layered soil systems with a high or low permeability interlayer reveal new insights. Such as a more than twofold increase in negative average excess pore pressure and time to reach 90% average degree of consolidation when the hydraulic permeability of the interlayer is one-tenth that of the surrounding layers. The study provides valuable insights for the design and evaluation of electro-osmotic consolidation in multi-layered soft soils.