Evaluation and analysis of pullout strength in pile group embedded in sandy soil using PLAXIS 3D

The pullout strength of pile foundations is a critical factor influencing the stability of underground and waterfront structures, especially when subjected to uplift pressures. This study examines the uplift capacity of model hollow circular aluminum piles, both as single units and in group configurations, with outer diameters of 2.54 cm and varying lengths of 60, 75, and 90 cm. Experimental investigations were conducted on pile groups arranged in 2 × 1, 2 × 2, and 2 × 3 configurations, maintaining a constant length-to-diameter ( L/ d) ratio of 24, 30, and 36. The spacing-to-diameter ( S/ d) ratio varied between 3, 4, and 5. The experimental results obtained strong validation from PLAXIS 3D numerical analyses that matched the experimental data. Rising pile embedment depth and spacing quantities lead to higher pullout strength levels. The evaluation of nondimensional parameters reveals the correlations between pile group uplift strength and embedment depth together with pile spacing. These research findings help foundation engineers to design piles for better uplift resistance, which results in better foundation practice improvements.