Research On Interaction Of Engineering Piles And Sheet Piles

Sheet piles is often used for excavation protection in costal areas of China. One pile with three usages means sheet piles are used to support loads from superstructures and to sustain lateral soil pressure for the basement besides working as retaining structures during excavation. As the pile group with variant pile diameters and pile lengths differs in composition from the conventional pile group with identical single piles, the combined action of engineering piles and fender piles is most important for mechanism of the technique of one pile with three usages.In previous study of the combined action of engineering piles and fender piles, piles are assumed to be straight lines without thickness in subsidiary stress computation, which will often cause errors to various degree. The error induced will decrease as the pile spacing increase. The correlation of error and pile spacing is discussed in this paper.Based on elastic methods, the single pile behavior is studied through Mindlin stress solution, followed by the analysis of interaction between two piles. Thus, the interaction factor is obtained, based on which the interaction between more piles in pile group can be considered using superposition principle.Two different raft analysis theories, namely, plate theory and thick raft theory, are also introduced in the paper.APGR, a program developed for analysis of combined action of engineering piles and fender piles based on the analysis method presented in this paper, is used to compute the behavior of a 30-story building in Frankfurt Clay. The influences of fender piles on pile cap reactions, settlements, moments and twist moments of raft are discussed herein. Two pile arrangement methods, that is, piles installed in the middle of a raft more than in the edge of a raft and piles installed in the middle of a raft less than in the edge of a raft, are compared in this paper. The effects of pile spacing and pile lengths of border piles and corner piles incorporating the concept of piles installed in the middle of a raft more than in the edge of a raft are also discussed in this paper.