Geophysical Characterization of Soil Properties for Infrastructure Development: A VES Study at the Awfi City Electrical Station, Babylon, Iraq

An electrical resistivity survey was conducted for the proposed Secondary Transformer Electrical Station project in Awfi City, Babylon Governorate, Iraq. Seven vertical electrical sounding (VES) profiles were acquired using the Schlumberger array with a spacing of 25 meters. The interpretation revealed 4 to 5 geoelectrical zones at each station, indicating significant variations in resistivity with depth. Low resistivity values (as low as 0.2 Ω.m at Station 4) correspond to clay-rich layers saturated with saline groundwater, typically increasing in concentration with depth. In contrast, high resistivity values (up to 36.3 Ω.m at Station 4) are associated with silt and sand layers, likely influenced by nearby freshwater sources such as the adjacent river. The investigated depths ranged from 0.2 m to 20.6 m, and layer thicknesses varied between 0.1 m and 27 m. These findings were consistent with the results of soil sampling, laboratory testing (TDS, pH, porosity, saturation), and groundwater analysis, confirming the influence of lithological and hydrogeological factors on resistivity variations. Overall, low resistivity zones were predominant at the edges of the study area, while higher resistivity values were observed near the center and topsoil, reflecting the complex interaction between soil texture, salinity gradients, and proximity to surface water. These results provide critical insight for geotechnical assessment and engineering planning of the station foundation.