# Electromechanical Behavior of Afyonkarahisar Clay Under Varying Stress and Moisture Conditions
## 5 Conclusions and Recommendations  
This study demonstrates a strong and consistent coupling between water content, mechanical behavior, and electrical resistivity in clayey soils. Laboratory tests under uniaxial compression showed that resistivity is influenced by both moisture level and stress stage. At low moisture content (10%), resistivity initially decreased due to compaction and then increased as microcracks formed. At higher moisture levels (20% and 30%), resistivity decreased steadily with increasing stress, reflecting improved ionic mobility and higher conductivity. The tested material, classified as high-plasticity clay (CH group, USCS), exhibits electromechanical responses typical of montmorillonite- and illite-rich soils, and the results are consistent with similar clay types. Furthermore, the shear strength of unsaturated Afyon clay was found to decrease linearly with increasing moisture content, confirming the dominant role of water in controlling strength parameters. This trend aligns with established literature and reflects the high sensitivity of such soils to saturation. However, the empirical relation shows limited validity at high moisture levels, where it may predict unrealistically low strength values. Although the empirical models used are based on the USCS classification system, their interpretation remains valid in practice. Nonetheless, when working within the ISO 14688 framework, it is essential to verify the compatibility of classification parameters to ensure accurate application of such models. Electrical resistivity was confirmed as a practical, non-destructive indicator of mechanical changes, with clear potential for use in monitoring soil behavior during compaction, infiltration, and slope deformation. When combined with techniques such as electrical resistivity tomography (ERT) or electrical impedance tomography (EIT), it enables spatially resolved, real-time observation of moisture dynamics. Based on these findings, we propose a site-specific monitoring system that integrates calibrated electrical resistivity measurements with in situ moisture sensors and meteorological data. Periodic ERT surveys and borehole-based measurements would enable continuous tracking of subsurface moisture and its impact on mechanical stability. This study was limited to the clay from the Afyonkarahisar region. The findings are consistent with previous research on montmorillonite- and illite-rich clays, highlighting the strong influence of moisture content on the mechanical behavior and electrical resistivity of soils. Similar to [PERSON] (2015) [26], [PERSON] (2007) [34], and [PERSON] (2004) [14], our results show a rapid decrease in shear strength with increasing water content, which is characteristic of high-plasticity clays. We also observed a decrease in electrical resistivity with increasing moisture and loading, aligning with prior findings on enhanced ionic mobility and microstructural changes. Differences arise when compared to clays with lower plasticity or different mineralogical compositions, such as kaolinite or organic-rich clays, where changes in mechanical and electrical properties are typically more moderate or driven by different mechanisms. This underscores the critical role of mineral composition and plasticity in determining the electromechanical behavior of soils. Overall, this study contributes to a broader understanding of soil mechanics by confirming the utility of electrical resistivity as a non-invasive indicator of moisture and mechanical changes in specific clay types. For future research, it is recommended to test a wider range of soils with varying mineralogical compositions and environmental conditions to develop more generalized models applicable across diverse geotechnical scenarios. Future research should also explore other clay types with varying mineralogy and structure to generalize the observed relationships. Additional studies are needed on the effects of cyclic loading and environmental variability on electromechanical coupling.