Large deformation analysis for piles on elastic or plastic foundation

A set of nonlinear differential equations for nonlinear large deformation analysis of piles with initial displacements on an elastic foundation or a plastic foundation are presented by the arc-coordinate, where the Winkler model is used to simulate the resistance of foundation to pile. The differential quadrature method (DQM) is applied to discretize the set of nonlinear equations, and the solving procedure is presented following Newton-Raphson scheme. The numerical examples show the configuration, bending moment and shear force of deformed piles subjected to combined loads. The effects of the elastic or plastic properties of soil, the initial displacement and loads on the mechanical behavior of piles are considered in detail. Then the analytical solution of a simplified model is obtained when the displacement is smaller, and the solutions obtained from both small deformation and large deformation theory are compared.