Abstract
An introduction of performance based design to infrastructures is on process. According to the performance based design, examination of not only bearing capacity but also long-term displacements of pile foundation are required in advance. On checking bearing capacity and displacements of pile foundation, it is important to consider the influence of pile group effect. Up to now, however, the research concerning pile group effect has focused horizontal resistance and displacement. In this research, pile group effect on bearing capacity and vertical displacement is examined through centrifuge model test and numerical simulation with soil-water coupling FEM, in which parameter is pile spacing (1.5D and 5.0D). As the result, followings are obtained; 1) evaluated from bearing capacity obtained through short-term load test, pile group effect is not appeared in pile spacing 5.0D; 2) evaluated from long-term displacements, pile group effect is appeared even in pile spacing 5.0D.
