Exploring the response of single piles and pile groups to lateral loading in sand using 3D FEM analysis

Piles are an essential component of any building, as they support the weight of the structure and transfer it to the ground. Typically, a pile not only bears the vertical force of the weight, but also lateral forces caused by wind, uneven supporting foundation soil (such as a slope), and other factors. When a single pile is subjected to lateral loading, its response can be complicated due to the interaction between the pile and the surrounding soil. This complexity increases when analysing a pile group containing multiple piles, due to additional interactions among individual piles. Therefore, it is important to investigate the behavior of single piles and pile groups under lateral loading. This research conducted a series of 3D finite element method (FEM) simulations on both single piles and various pile groups, comparing the results with the corresponding physical model tests performed in previous studies. An influence zone, which can only be visualized through 3D FEM, was introduced to explain the interaction among different single piles in a pile group. The findings are as follows: the relationships between the lateral pile load and pile deflection predicted by 3D FEM are close to those observed experimentally. The box-pattern pile groups are more susceptible to shadow and edge effects than those arranged side-by-side. As the pile spacing increases, the influence zone’s effect decreases, and the pile group efficiency increases. The group efficiency has a relation with the influence zone visualized by 3D FEM.