Engineering Site Investigation Using 2D Electrical Resistivity Imaging, K3 Area, Western Anbar Governorate

Subsurface cavities and weak zones have a significant influence on the long-term feasibility of infrastructure and buildings; these problems must be considered before beginning construction of buildings and town decisions. Assessing the hazard associated with these cavities requires a greater understanding of the complex behavior of the karst structure, which is best developed in a region that absences indicators on the ground surface. This study investigates the subsurface characteristics in the K3 region using 2D electrical resistivity imaging (ERI) to recognize and describe underground structures. The data acquisition has been conducted manually along four 2D traverses, each 97 m long, using a dipole-dipole array with 20 electrodes spaced at 5 m apart. The data are processed using the RES2DINV software with a robust method to generate a 2D resistivity model. The results show distinct high-resistivity anomalies; these are suggestive of several cavities with a variety of depths from 3 to 15 m below the surface, with a width of 35 m. Also, several subsurface weak zones reveal that they are more severe at depths of 1.25-5 m below the ground surface. These zones associated with subterranean channels, cavities or sinkholes lead to issues with new construction and potential foundation subsidence. The investigation successfully charted the spatial distribution, depth, and approximate size of the detected cavities and weak areas. These findings have crucial importance to the assessment of geotechnical risk and urban planning in the K3 region; the efficacy of 2D ERI in the detection of subsurface structures is demonstrated.