Bearing behaviors and design method of laterally loaded batter pile groups (BPGs) in sand

In recent years, the batter pile groups (BPGs) are increasingly used in offshore engineering; however, the optimal and economic design of BPGs is still poorly understood. Therefore, in this study, the lateral bearing behaviors of a typical 2 x 2 BPG in sand are comprehensively investigated by experimental and numerical methods. Firstly, a 1g scale model test was carried out to study the effect of pile inclination on the responses of BPGs under lateral loads. Secondly, a total of 44 finite element (FE) models considering various conditions are utilized to reveal the lateral load bearing mechanism of BPGs, and the influence of design indicators on the lateral bearing capacity (Hu) of BPGs is thoroughly studied through a parametric study. Finally, an empirical design method is proposed based on 32 numerical model results to predict the bearing ratio (gamma) as well as the lateral bearing capacity of BPGs in sand. The results show that, as the batter angle (theta) becomes larger, the lateral bearing capacity increases, and the maximum bending moments of both front-row piles (FRPs) and rear-row piles (RRPs) decrease, which means the shadowing effect on the RRPs is also reduced. With the increasing of batter angle (theta), the improvement effect of the pile length on the lateral bearing capacity becomes more significant, and the enhancement effects of the pile diameter and the relative density of sand on the lateral bearing capacity are decreased. The conclusions derived from this study can provide guidance for the design of BGPs in practice.