Deformation model of sand around short piles under pullout test

Piles as a member of structures can be failed due to structural collapses or soil’s body failure. Extensive experimental studies have been conducted in literatures to identify the behavior of piles failure mechanism in sand. Nevertheless, the number of researches with respect to uplift failure of short piles are limited and this issue needs to be studied. In this study, three small-scale physical tests were performed to investigate the uplift resistance of short piles in loose sand with pile diameter of 5 cm and slenderness ratio of 2, 3 and 4. Close photogrammetric technique and Particle Image Velocimetry (PIV) were also employed to observe the deformation patterns due to uplift force. For verification purposes, the results obtained from the laboratory tests were compared to the results of ABAQUS finite element method (FEM) software. It was found that the slenderness ratio is the most influential factor on the pile uplift capacity values obtained by experiments. In addition, a reasonable error was observed between the measured bearing capacities obtained by experiments and the results of the numerical modeling. The minimum and maximum errors of 0.6% and 11% between experimental and numerical results reveal that the ABAQUS software can simulate the experimental tests behavior with high degree of accuracy. Besides, similar failure zone was achieved by both PIV and numerical techniques.