Investigation on determining uplift capacity and failure mechanism of the pile groups in sand

Foundations of some structures such as transmission towers, mooring systems for ocean surface or submerged platforms, tall chimneys, jetty structures are subjected to uplift loading. In such cases, to increase the uplift resistance of piles, pile foundations like anchored piles, batter piles and micro piles are extensively employed depending on in-situ conditions. This paper deals with the contribution of pile surface to the uplift capacity and the failure mechanism obtained for the pile groups in sand, and the main goal of the study is to investigate the effect of the pile surface roughness on the uplift capacity for different spacing ratios between piles. Therefore, the paper presents some findings of a single pile and pile groups embedded in sand under uplift loading. The variables investigated include the pile surface, pile embedment ratio and the spacing ratio between piles. Experiments were conducted to study foregoing parameters, and three-dimensional analyses were performed using the finite element method to illustrate the failure mechanism of pile groups and the interaction between piles for different spacing ratios between piles. The results show that the finite element simulation results indicate good agreement with the experiment results, and all variables significantly affect the uplift capacity of piles. •The paper deals with the effect of pile surface roughness on the uplift capacity for different spacing ratios between piles.•The pile surface roughness positively affects the uplift capacity.•The uplift capacity of pile group raises with the increase of spacing ratio between piles as pile-pile interaction reduces.•The interaction between piles disappears at S/D = 8 and 10 for the smooth and rough pile groups, respectively.