Injection of saline solutions to improve the electro-osmotic pressure and consolidation of foundation soil

Injection of saline solutions can enhance the effect of electro-osmotic pressure. This study considers the consolidation and stability of foundation soil for building construction. Kaolinite (KGa-1) and Taipei silty clay were subjected to zeta potential (ZP), electro-osmosis and laboratory vane shear tests with injection of saline solutions. The ZP values decrease (i.e., less negative potential) with increased cationic valences and concentrations. The increased electro-osmotic permeability from injecting CaCl2 (1 N, EOC5) solution is about 172% higher than that without injection due to an increase of drained water from the cathode and the resulting increase of undrained shear strength. Average undrained shear strength for injecting CaCl2 solution over a period of 7 days is about 4 to 5 times greater than that without injection during electro-osmosis tests. Electro-osmosis tests with injection of saline solutions reveal that the increase of undrained soil shear strength (ΔSu) is proportional to the ZP tests.