The unconfined compressive strength and shear strength represent the basic mechanical properties of clayey soil. If the soil in its natural state does not have sufficiently good mechanical properties, in engineering practice, it can be improved by chemical stabilisation of the soil. The stabilisation procedure involves adding reagent(s) to the soil with the aim of permanent improvement in the mechanical properties of the soil. In this study, the individual effects of seven different chemical stabilisers (traditional and alternative) on the mechanical properties of clayey soil were analysed. In the first stage of the research, comprehensive analyses were conducted on the effect of each of the selected stabilisers on the compressive strength of the soil. Each of the selected stabilisers was considered with three different content percentages in the soil mixture, with the aim of determining the optimal stabiliser content. Unconfined compressive tests were conducted to determine the unconfined compressive strength (UCS) of the soil. In the second stage of the research, extensive analyses of the effects of each of the selected stabilisers alone on the improvement in soil shear strength parameters (cohesion and internal friction angle), were carried out with the optimal content of each of the stabilisers. The shear strength parameters were determined by direct shear tests. Both stages of the research were conducted at three different time intervals after the chemical stabilisation (3, 14, and 28 days) in order to determine the long-term efficiency of the chemical treatment of clayey soil. Based on detailed comparative analyses, it was determined that all the selected stabilisers contributed to a lesser or greater extent to a significant improvement in the analysed mechanical properties of clayey soil. A statistical analysis of the obtained results was also conducted using the method of analysis of variance (ANOVA), on the basis of which the individual effect of each selected stabiliser on improving the mechanical properties of clayey soil was validated and quantified.

One of the innovative and promising approaches to the stabilization of fine-grained soils with low bearing capacity is electrokinetic treatment which can be integrated with other techniques to enhance soil properties. This method could involve applying a low direct current through electrodes inserted into the soil while simultaneously introducing stabilizers through the electrokinetic process. The stabilization achieved in this way contributes to the improvement of the physical, chemical and mechanical characteristics of the soil. However, a significant challenge of this method is the corrosion of electrodes, which occurs due to electrochemical reactions at the interface between an electrode and the soil. When direct current is applied, oxidation and reduction reactions take place at the electrodes, leading to the dissolution of the electrode material. This can cause the reduction of the electrodes efficiency and longevity, impacting the overall effectiveness of the treatment. Consequently, it is important to examine the extent to which electrode corrosion can affect the flow of current and processes in the soil during the application of this innovative method. Therefore, the aim of this paper is to further elucidate the effects that occur when varying the parameters that affect the current flow.