Analysis and intrinsic correlations of partially head-restrained piles under lateral loading: virgin sites and new-existing pile sites.

Piles are commonly used under partial head-restraint conditions. Currently, quantification of the lateral capacity of partially head-restrained piles is an open problem. This paper reports the results of a comparative study on the partially head-restrained behaviours of single piles in virgin sites and new piles in sites with existing piles. The lateral performance of new piles affected by pile-head restraints was examined and compared with that of single piles in virgin sites, and the characteristics of new and single pile capacities with respect to pile-head restraints were evaluated. An intrinsic H–δδ correlation (the lateral pile capacity and the factor linking partially head-restrained piles to pure free- and fixed-head piles) is discussed, which enables the calculation of capacities of partially head-restrained piles based on those of pure free- and fixed-head piles. In addition, analytical models of the δδ–λ correlation (λ represents the pile-head restraint percentage) are deduced. By combining the δδ–λ and H–δδ correlations, the lateral pile capacities for arbitrary pile-head restraints in virgin sites and sites with existing piles are calculated. The proposed method is comprehensively validated by numerical and literature examples, showing significant advantages in the determination of the lateral pile capacity considering head restraints. [ABSTRACT FROM AUTHOR]