Abstract

In this research, the behaviors of pile group models under uplift load have been investigated. The tests were conducted in two different models, laboratory (an experimental model) and numerical (by ABAQUS software). In both models, the load application method is strain-controlled. The goal is to evaluate pile groups' net final uplift force and efficiency while two determining factors change. For the first factor, the ratios of pile spacing to diameter (s/d) are considered 2, 4, and 6. For the second factor, the arrangements of pile groups are in three forms: liner (2×1), square (2×2), and rectangular (2×3). The effects of the two parameters on uplift capacity and pile group efficiency are not the same. Also, the amount of uplift capacity and pile group efficiency doesn’t vary linearly. By increasing the ratio of pile spacing to diameter the net final uplift capacity and relevant efficiencies increases at first step and then tend to be constant. Although the changes in pile arrangements from linear to rectangular conclude greater net final uplift capacities, the pile group efficiencies decrease. In this research, the maximum efficiency is allocated to the linear pile group (2×1) with s/d of 6.

Key words: Pile group arrangements, efficiency, uplift load, compact sand, pile spacing.