Effect of pile cross-section shape on pile group behaviour under lateral loading in sand

Whenever superstructures are under large lateral loading, designers prefer to use piles. Pile design always has been attractive for engineers as numerous factors are involved. However, few studies are available on the effects of different cross-section shapes of the pile on the lateral resistance of a pile group. In this experimental study, four different pile cross-section shapes – fin, square, pipe and H-shaped sections – with the same surface areas were used and their lateral resistance under different conditions, such as arrangements of piles, pile spacing and relative density of sandy soil, were compared with each other. The results revealed that pile groups with fin and H cross-section shapes had the highest and the least lateral resistances, respectively, and the H-section piles represented the largest group efficiency. The ratios of lateral resistances of fin, square and H-shaped piles to those of pipe piles were 1·4, 1·19 and 0·85, respectively. The group efficiency of all piles with different section shapes was more than 1 for a pile spacing of six times the pile diameter (6D_P). Moreover, while the relative density of the surrounding soil increased from a loose to a dense state, the group efficiency of all cross-section shapes of piles reduced by about 50%.