Single Beam Analogy for Analyzing Nonlinear Soil-Pile Group Interaction under Lateral Loading

摘要

The problem of designing grouped piles to resist lateral loads is often encountered in foundations for supporting structures. Grouped piles subjected to lateral loading are influenced by the existence of neighboring piles. This pile-soil-pile interaction is strongly dependent on the pile-to-pile spacing, which dominates the pattern of stress and deformation around a pile group. In this paper, a simplified approach in which a group of closely-spaced piles is viewed as an equivalent single upright beam has been developed for evaluating the stiffness of a rigidly capped pile group. The equivalent single beam, whose lateral stiffness is dominated by the product of the bending stiffness of an individual pile and the number of piles, is different from a Bernoulli-Euler or Timoshenko beam. With introduction of the active length, below which the deflection of piles becomes negligible, the overall behavior of a rigidly capped pile group can be described for nonlinear behavior of soils surrounding grouped piles. Investigation on several static lateral pushover experiments showed that the equivalent single upright beam analogy has a potential to be used to evaluate the stiffness of a pile group embedded in either a linear or nonlinear soil stratum in limited number of parameters.