Ensuring the structural soundness of pile foundations is essential for demonstrating the safety of a foundation system’s design. In the case of bored cast-in-situ piles, integrity is determined by physical dimensions, pile continuity, and the consistency of the concrete. The uniformity of bored piles directly influences load distribution, structural stability, design considerations, construction efficiency, risk mitigation, and the long-term performance of the foundation. Given the increasing demand associated with urbanization, pile foundations are frequently constructed in challenging site conditions to safely dissipate the huge superstructural loads safely to the earth. The current study focuses on a scenario where a considerable number of pile foundations are installed in alluvial deposits. Pile integrity tests were conducted to evaluate the quality and integrity of these bored pile foundations. During the integrity testing, one pile was identified as having a defect, showing a quantified 40% reduction in cross-sectional area at various depths along the shaft length. To assess whether the defective pile could withstand geotechnical ultimate capacity in axial compression beneath the ground improved (GI) soil cement layer, a simulation study was performed using numerical methods. The simulation began with validating the model through a single pile simulation using PLAXIS 3D. Subsequently, the same pile-soil model was used as a reference for simulating the defective pile. Additionally, the permissible concrete stresses were examined to determine the acceptability of the defective pile for axial compression. The results were further compared with the available data from conventional static load test results to arrive at design geotechnical ultimate capacity.