The Influence of Voltage Gradient Application History on Electro-Osmotic Reinforcement of Marine Soft Clay

The electric potential gradient is a key factor in electroosmotically reinforcing soft clay. Its application history induces a series of physical and chemical reactions within the soil, influencing the selection of the gradient in the subsequent stage. To gain a deeper understanding of this complex process and its inherent mechanism, electroosmotic reinforcement tests on soft clay were conducted under varying electric voltage gradients. The changes in parameters, including current, drainage volume, shear strength, and water content within the soil, under different application histories of the voltage gradients, were measured. The experimental results demonstrate that the magnitude of the voltage adopted in previous historical stages had a significant impact on the current drainage situation as well as the enhancement of shear strength. During the studied historical period, a relatively high voltage gradient was applied until soil drainage stopped. However, at present, it has become extremely challenging to substantially increase the drainage volume regardless of whether the electrification voltage gradient remains stable, rises, or falls, even when the current does not drop too low. For soil with a high activity index, under an appropriate voltage, the input electrical energy can be more efficiently converted into various physical and chemical processes that enhance soil reinforcement. Regardless of the voltage gradient level adopted, the application of a low voltage gradient in the historical stage exerts a more beneficial influence on the current stage than a high voltage gradient. During the electroosmosis process, efforts should be made to maximize the drainage duration as it facilitates the promotion of the chemical reinforcement effect and reduces energy consumption.