The successful execution of deep underground engineering projects depends heavily on comprehensive and accurate geomechanical modeling. Among various geomechanical parameters, the rock mass integrity coefficient (Kv) plays a critical role in assessing the stability and associated risks of subsurface structures. However, accurately determining Kv is often constrained by the high costs, time demands, and limited spatial coverage of conventional borehole-based methods. To address these limitations, this study presents a novel application of the Controlled Source Audio-frequency Magnetotellurics (CSAMT) method to generate 2D and 3D Kv models across a geologically heterogeneous site at depths reaching 1 km. This geophysical approach offers a non-invasive, costeffective, and efficient alternative for rock mass characterization. The results contribute to a better understanding of complex subsurface conditions, enhance early-collapse risk assessment, and support safer, more economical design of deep underground infrastructures. In regions with limited geomechanical data, this method helps bridge the gap between sparse field measurements and reliable geomechanical modeling, ultimately enabling more accurate and objective geotechnical evaluations.