3D Analysis interaction of piles groups under vertical load

The study of the response of deep foundations under different types of stress was the subject of several studies, but it is always very useful to understand the phenomena accompanying the behavior of these foundations in contact with the ground, and to propose simple and more efficient approaches.

This paper presents a numerical analysis of the response of a pile foundation subjected to axial load with taking account the soil-pile interaction. The analysis of the composite pile–soil system was performed using the Finite Element Method (FEM) using software Plaxis 3D tunnel. The pile- soil analyses and design is an interaction three dimensional problem, wherein, the applied load is transferred by a complicated interaction process between the piles and the soil. To reduce the analysis volume of interaction problems, it is necessary to have a relatively simple design procedure so that the preliminary design can provide adequate but reasonably accurate data for the final analysis. The method consists to replacing two configurations of pile group with a single equivalent pier of the same length and an equivalent diameter. This equivalent pier is described by his material properties that result of the homogenisation of the piles and the surrounding soil. In this study, two types of symmetric and asymmetric pile group configurations are examined. The numerical results of settlements were compared with the field measurements collected from case history, which showed good agreement. The pier equivalent method can decrease the interaction factor of 2×2 pile groups by 16% than the interaction factor of single pile group.