A new BE formulation coupled to the FEM for simulating vertical pile groups

The aim of this work is to obtain a numerical tool for pile–soil interaction analysis. The soil is modeled as an infinite domain in radial directions. The piles, considered cylindrical, are modeled with the finite element method (FEM), using one-dimensional elements. Displacements and tractions along the shaft are approximated by polynomial functions. The soil is modeled using the boundary element method (BEM) with Kelvin fundamental solutions. Infinite boundary elements (IBEs) are employed for the far field simulation, allowing computational cost reduction without compromising the accuracy. The IBE formulation is based on a triangular boundary element with linear shape functions instead of the commonly used quadrilateral IBEs. By coupling the FEM–BEM formulations, a single system of equations which represents the complete pile–soil interaction problem is obtained.