This study comprehensively addresses the mechanical stabilization of earth (MSE) walls, with a particular focus on internal stability assessed through direct shear and pullout tests. Emphasizing the critical evaluation of frictional characteristics between soil and geogrids in civil engineering applications, the pullout test measures surface-frictional force and passive resistance concurrently. Notably, the study introduces significant modifications to a large-scale direct shear test setup, involving the replacement of the shear box with a specialized rectangular box (900 mm × 500 mm wide, 500 mm height) featuring a front face slot. These alterations aim to enhance the evaluation of soil-geosynthetic interaction parameters during pullout, ensuring smoother stress transfer across the entire displacement range. Furthermore, this research explores the application of non-conventional fill material, specifically coal mine waste (CMW), in pullout tests. As a result, the study observed that increasing confinement pressure positively influenced peak pullout values, while variations in density showed slight effects dependent on geogrid tensile strength. Specimen length exhibited a modest impact on peak pullout with minimal changes in displacement. Notably, reducing the sleeve distance led to geogrid rupture, particularly at lower tensile strengths.