Analysis of Influence of Quantity and Spacing of Piles on Group Effects in Low-rise Pile Foundations

Abstract

In pile foundation structures, when piles are arranged closely, they interact with each other through the pile-soil interaction, and the load transmission of the entire pile group to the soil is different from that of individual piles, resulting in an impact on the load-bearing capacity of the pile group. The collective effects of the interaction among piles in a group are commonly referred to as "group effects". This paper presents the research findings and analysis of the interaction effects of piles in a shallow pile foundation system under static compression loads. The study indicates that the pile spacing and the number of piles in a group significantly affect the magnitude of stresses in the overlapping regions, thus altering the group effects in a pile group. Increasing the pile spacing reduces the group influence factor, but this can be disadvantageous for the load-bearing capacity of the pile group, especially for single pile foundations beneath structural columns, leading to uneven distribution of forces acting on the pile heads in the group. Additionally, the arrangement of piles also needs to be considered for its influence.

Keywords: Single pile; group of piles; low-rise pile foundation; pile group effect; Pile spacing.