Study on the Electro-Osmosis Characteristics of Soft Clay from Taizhou with Various Saline Solutions

Chemical electro-osmosis with an injected saline solution can be described as an efficient method for adjusting the soil microstructure and improving soil conductivity, and the effect of electro-osmotic consolidation on soft foundations can also be improved by this novel technology in regard to foundation treatment. To better study the electro-osmotic characteristics of soft clay from Taizhou with different grouting solutions, a series of chemical electro-osmotic experiments concerning the injection of CaCl2, MgCl2, NaCl, KCl, and deionized water were conducted in the laboratory based on custom test devices. The actual treatment effects of these experiments were compared by monitoring the drainage, current, voltage, elemental mass fractions in the soil, and soil structure. The chemical electro-osmotic method was further studied from a theoretical perspective based on the inherent link between the macro- and microlevel indexes. The results of the model test indicated that the crystal structure of the soil changed from an initial flocculated structure to a granular or laminated structure with the injection of CaCl2 and MgCl2 saline. Na+ was hereby replaced by multicharged ions, which served as the key factor that affected both the drainage efficiency and conductivity of the electro-osmotic process. Moreover, a novel one-dimensional electro-osmotic consolidation equation was introduced that considered variations in the electro-osmotic permeability coefficient, which better illustrated how the excess pore water pressure was deduced when compared with Esrig’s consolidation equation. Furthermore, the results of this experiment may be adopted as a reference or as evidence for the subsequent promotion and application of the electro-osmosis method.