Numerical study of 2D & 3D ERT with sensitivity analysis for subsidence in the coal mining area

Abstract

<p>Subsurface cavities are mainly responsible for ground subsidence in and around coal mines. There is need to use an advanced high-resolution three-dimensional (3D) Electrical Resistivity Tomography (ERT) technique to detect anomalies and map subsurface precisely. The present study demonstrated the numerical evaluation of 2D and 3D-ERT for air-filled and water-filled cavities. Models simulated with reasonable resistivity values for voids and formations by considering bord and pillar mining environments in multilayer earth. Wenner, Wenner-Schlumberger, and Dipole-dipole arrays incorporated with and without a barrier to getting the best possible output. We used the Res2dinv and Res3dinv programs for data processing. 3D Dipole-dipole inverted geo-electrical section better showed the subsurface cavities signature than the results obtained from other applied arrays. The sensitivity section corresponding to used electrode configurations gives a more detailed picture of the subsurface for better interpretation. The 3D volume of the subsurface overcomes the limitations of 2D ERT to detect cavities within the coal seam.</p>