# Electromechanical Behavior of Afyonkarahisar Clay Under Varying Stress and Moisture Conditions
## 4 Implementation  
In this study, a methodology was developed that integrates laboratory analysis of clay soils with advanced field measurement techniques to monitor physical changes in soils, particularly moisture content, porosity, and mechanical resistance. This approach is highly relevant for various branches of geotechnical and environmental engineering, where accurate information on soil conditions is essential for stability assessment, design, and environmental impact monitoring. The laboratory investigations focused on quantifying the relationship between the electrical resistivity of soils and their mechanical properties. Measurements on samples taken from boreholes included gravimetric determination of water content, electrical resistivity measurements using a two-electrode method, and mechanical tests such as strength, cohesion, and elastic modulus. The results consistently demonstrated a correlation between moisture content and electrical resistivity, with higher saturation corresponding to lower resistivity values. This finding aligns with the observations of [PERSON] et al. (2020) [36], who studied transport properties in unsaturated soils. Based on these results, empirical correlations were established to enable the transfer of laboratory findings to field conditions. This calibration forms the foundation for interpreting field measurements, where electrical resistivity tomography (ERT) was selected as a key method, supported by the installation of moisture sensors (e.g., TDR, FDR) and local meteorological stations to record precipitation, temperature, and evapotranspiration data. Field monitoring using ERT and sensors enables time-lapse (4D) observation of infiltration, saturation, and soil drying processes, allowing the detection of mechanical property changes such as reduced shear strength due to increased moisture. Using correlation functions derived from laboratory measurements, field-acquired resistivity data can be converted into estimates of soil moisture content and, in some cases, approximate mechanical properties of the soil. This interpretation is especially valuable in geotechnical site investigations, including assessments of slope stability and landslide risk. One of the key applications of this methodology is detecting the impacts of climate change on soils. The increasing frequency of extreme weather events (e.g., prolonged rainfall, droughts) alters the soil's water balance, affecting shear strength and potentially causing subsidence, cracking, or even triggering landslides. Early detection of these  
Figure 11: Water content vs. electrical conductivity (_EC_) at max. Uniaxial compression stress. changes through ERT and sensor networks allows timely, targeted interventions such as drainage improvements or soil reinforcement. Moreover, the methodology is not limited to geotechnical stability but also provides effective support for geothermal applications. Electrical resistivity is directly related to soil temperature and saturation, which are critical parameters for the design and operation of shallow geothermal systems such as ground-source heat pumps. Overall, the combined use of laboratory and field methods represents a robust, non-invasive, and adaptable tool for early detection of soil changes, risk management under climate change, and the development of sustainable energy solutions. The tested material corresponds to high-plasticity clays (CH group, USCS), exhibiting electromechanical behavior typical of soils rich in montmorillonite and illite. Comparative data confirm that this behavior is representative of similar clay types (see Table 3). Compared to other clay types presented in Table 3, the clay from the Afyonkarahisar region exhibits characteristics typical of high-plasticity clay (CH), with a pronounced presence of montmorillonite, which strongly influences its mechanical and electrical behavior. Laboratory tests have shown that this clay is highly sensitive to moisture content changes, exhibiting a rapid decrease in shear strength with increasing water content.