Effectiveness and reversibility test of electrochemical modification of mudstone hydro-mechanical parameters

To study the modification effect of the hydromechanical parameters of mudstone after electrochemical modification and the reversibility of this modification, AlCl3 solution and Fe were selected as the electrolyte and electrode materials for the electrochemical modification test. The shear strength of the mudstone specimens was used as an evaluation index to evaluate the effect of electrochemical modification. The results of the electrochemical modification test of mudstone, using the controlled variable method, showed that the shear strength of the modified mudstone increased by about 1.4 times compared to the unmodified mudstone when a 20% AlCl3 solution and Fe electrode were used. The saturated water content of the modified mudstone, after re-absorption of water, was significantly reduced. The saturated water content of the specimens in the anode and cathode groups of the Fe electrode were 23.2% and 18.2%, respectively. The liquid limit water content after modification was 32.489%, which was lower than the 35.266% of unmodified mudstone, while the plastic limit water content increased from 20.728–22.697%. The water absorption rate of the modified mudstone specimens decreased significantly, with an average water absorption rate of 0.13 g/h, compared to 0.19 g/h for the unmodified mudstone. Through electrochemical modification, the mechanical strength of the mudstone was significantly improved, and its hydrophilicity and water absorption capacity were significantly reduced. The mudstone also exhibited an obvious strain softening feature after re-absorption but still showed a certain enhancement compared to the as-reinstated soil. This indicates that the electrochemically modified soil has a certain degree of reversibility after softening again upon contact with water.