Mechanism and experimental tests on reducing adhesive force of clay-metal interface with electro-osmosis method

Mechanical construction is widely used in geotechnical engineering, but clay clogging is a major problem that hinders construction. Shield, drilling pile machine and other equipment are prone to mud cake, clogging, poor soil discharge and other phenomena during the construction in clay stratum, which leads to increased torque of the apparatus, intensified tool wear and reduced construction efficiency. Clay clogging generally occurs at the interface between clay and metal surfaces, and reducing the adhesion force of clay to metal surfaces is the key to solving the above issues. This article introduces a method of using electro-osmosis technology to form a water film between the clay and metal interface to reduce the clay adhesion. Tilted-plate tests and electro-osmosis tests were conducted on four types of clay under different voltage and water content conditions. The experimental results show that the electrodynamic behavior of clay is not only influenced by water content and clay minerals, but also needs to meet a certain voltage threshold. The critical sliding voltage threshold of the four clay samples in the experiment is concentrated at 4 V, with slight differences influenced by the water content. After the voltage exceeds the threshold, the detachment time of the soil sample decreases sharply. Increasing the voltage from 9 V to 11 V does not show a significant difference in detachment time. After the voltage exceeds 7 V, increasing the voltage has little effect on reducing the stickiness of the soil sample, but the energy consumption during the electro-osmosis process increases significantly. When applying electro-osmosis method in practical engineering, factors such as energy consumption and formation conditions should be considered comprehensively, so as to select the optimal voltage-based electro-osmosis viscosity reduction program and improve the construction efficiency.