Study on effect of vertical load on performance of horizontally-loaded pile foundations through three-dimensional finite element analyses

The effect of vertical load on the horizontal response of pile foundations including pile group and piled raft are investigated through a three-dimensional finite element method. In this study, horizontal load tests on pile foundation models, working in different supporting conditions of pile group or piled raft, in a dry silica sand ground are simulated. The hypoplastic model, an incrementally nonlinear constitutive model, is used to model the ground. The foundations including raft and piles are modelled as linear elastic. The analysed results of a typical case are compared with the results of the corresponding model load test, which was carried out by the authors, to evaluate the applicability of the numerical model. After that, a series of numerical analyses are conducted to investigate the influence of vertical load on the horizontal response of the foundations. The analysed results indicate that the increase of vertical load leads to the increase of the horizontal resistance and the internal forces of the piles are influenced by the vertical load level.