Elastic-plastic contact analysis of laterally loaded piles.

Abstract

For a laterally loaded slender pile, the soil near the pile will have plane strain behavior; on the other hand, the soil away from the pile will behave 3-dimensionally. Such a nonuniform displacement in one field (soil) is best handled by a singular perturbation method. A unified approach for linear and nonlinear analyses, using a singular perturbation technique, is accomplished. For linear analysis, the soil is divided into inner and outer regions. The inner region is modelled as a 2-D (horizontal) plane, and the pile is considered as a rigid inclusion. The outer region is modelled as a 3-D continuum, and the pile is considered as a line loading. Analytic solutions are found for both regions and an overall solution is then obtained using the method of matched asymptotic expansions. As for the pile, it is modelled as a beam. Finally, by applying a displacement compatibility condition on the soil-pile interface, these two independent formulations--soil and pile--can be linked and solved. For nonlinear analysis, since soil yielding and interface separation are local effects within the inner region, the nonlinear effect is incorporated by means of a correction to the linear inner solution. This is obtained by using a boundary element method for an elastic-plastic contact analysis in a 2-D substitute problem. Comparison with experimental results obtained from the literature shows reasonable agreement.