Analysis of Internal Forces and Deformation for a Single Pile in Layered Soil Based on the p-y Curve Method

Abstract

The p-y curve method can be used to describe the stress–strain relationship of soil under elastic, elastoplastic, and plastic states, and is more accurate than other methods in dealing with the nonlinearity of pile–soil interaction. However, the p-y curve method also has several limitations. First, when constructing the p-y curve, undrained shear strength Cu is taken to be constant, and the diversity of soil layers around the pile side are also not considered. Second, in the analysis of the internal forces and deformation of the pile, the influence of the vertical load from the top of the pile and the self-weight of the pile, are both ignored. Third, in the analysis of internal forces and deformation, the pile side soil is set equivalent to a homogeneous soil layer, and the layering of the soil is not considered at all. In order to study the nonlinear problem of internal forces and deformation of a single pile in layered soil in greater detail, this paper analyzes a calculation model based on Wang’s calculation model, and compares several commonly used p-y curve calculation models. An internal force and deformation analysis model for a laterally loaded single pile, that explicitly considers the second-order effect is then established, by considering the differences between p-y curves of different soil types, as well as the change in Cu with depth. The differential equation of pile deflection for a single pile in layered soil is also presented, together with the corresponding finite differential solution algorithm program. This model was validated using a horizontal load test of a pile, and comparison of the calculated results with the measured results shows that the method outperforms existing p-y curve methods for deformation and internal force analysis of horizontally loaded piles.