## 5 Discussion
### Electrode Material Optimization  
In this study, electrochemical experiments using three electrode materials (graphite, aluminum, and iron) were conducted, and their shear strength was evaluated after the experiments. Figure 9 depicts the modifications of the electrode sheets at the end of the electrochemical modification test. The graphite electrode underwent no significant changes, whereas the anode of the iron electrode corroded severely, with new areas of rust and yellowish-brown rust (Fe\({}_{2}\)O\({}_{3}\)) and small black areas (Fe\({}_{3}\)O\({}_{4}\)) visible on its surface. The anode corrosion of the aluminum electrode was also severe, with a significant amount of white material being lost (Al\({}_{2}\)O\({}_{3}\)). The cathodes of all three electrode materials experienced minimal corrosion, with more mudstone particles adhering to their surfaces due to the cathodes absorbing cations from the solution and mudstone particles around the clumped cations when energized. Figures 10 and 11 depict the results of the modified specimens' shear strength tests with the three electrodes at the optimal electrolyte concentration (10% AlCl\({}_{3}\)). The effect of the aluminum electrode on the specimens was relatively minor and the specimens remained soft and plastic, indicating that the specimen still had a high water content; in the iron electrode group, more iron ions penetrated the surface of the anode area and the penetration depth nearly reached the cathode. The sample surface changed colour, which makes it clear that it is not the same colour as the surface of the cathode. Figure 10: Surface of specimens at 3 electrode conditions (10% AlCl\({}_{3}\)). (**a**) Graphite electrode. (**b**) Iron electrode. (**c**) Aluminum electrode. Figure 9: Electrode after electrochemical reaction. (**a**) Graphite electrode. (**b**) Iron electrode. (**c**) Aluminum electrode. Three electrode materials were used for the electrochemical modification of mudstone, resulting in mudstone samples with different shear failure characteristics, as shown in Figure 11. The mudstone samples modified with graphite and iron electrodes exhibited brittle fracture characteristics, whereas those modified with aluminum electrodes still exhibited plastic fracture characteristics. Using the same 10% AlCl\({}_{3}\) solution, the aluminum electrode-modified samples showed plastic damage, which conflicts with the results of the electrolyte solution comparison mentioned earlier. By comparing Figure 8b, it can be seen that when the concentration of Al\({}^{3+}\) in the solution reaches 25%, the shear failure characteristics of the modified sample align well with the shear test curve of the aluminum electrode-modified mudstone sample in Figure 11. This indicates that when aluminum electrodes and an AlCl\({}_{3}\) solution are used to modify mudstone, the concentration of Al\({}^{3+}\) in the solution increases, leading to a decrease in the shear strength of the modified mudstone. This further confirms that the modification effect of the 10% AlCl\({}_{3}\) solution is better. The other two electrode materials did not change the concentration of the electrolyte solution. The shear test curve characteristics of the modified samples were consistent, and the graphite electrode showed a better modification effect on mudstone. As the electrode material influences the electrochemical modification of mudstone, this study found that the graphite electrode has the best modification effect. Experts and academics have also conducted relevant research in this field. [PERSON] et al. [16] performed a laboratory electrochemical modification of silt using electrodes made of iron, graphite, copper, and aluminum. The experimental results demonstrated that the effects of different electrode materials were directly reflected in voltage loss, with comprehensive comparisons identifying iron as the optimal electrode material for electro-osmosis.