Abstract
The use of helical piles as a group to sustain large compressive loads has increased in the recent decade, and an appropriate evaluation of their behavior is essential for a robust design. Therefore, a sequence of analyses via numerical modeling was conducted to evaluate the behavior of helical pile groups of different geometries and configurations installed in sandy soil. The 3D nature of the problem was modeled using Midas GTS NX and was calibrated and validated against field data. In this study, 2 × 1, 2 × 2, 5-piles, and 3 × 3 double- and triple-helix free-standing pile groups in a symmetrical arrangement were considered. The group effect on the ultimate load capacity and the settlement of each group were expressed in terms of group efficiency and settlement ratio. The load-transfer mechanism and its variation with group configuration were also explored and presented. The results indicated that center-to-center pile spacing, number of piles, helix-to-shaft diameter ratio, number of helices, and the method used to interpret the test data significantly influenced the group efficiency and settlement ratio, being more significant in the latter compared with the former. Moreover, center-to-center pile spacing and embedment depth contributed to the shape of the load-transfer mechanism of helical pile groups. The results of this study can be used to better predict the behavior of helical pile groups in sandy soil.