Analysis of lateral loading of pile groups using embedded beam elements with interaction surface

Abstract

The numerical simulation of soil-pile interaction problems, by means of full 3Dfinite element models, involves a large number of degrees of freedom (DOF)and difficulties during the mesh generation process. In order to reduce theunknowns and simplify and properly analyze such class of geotechnical prob-lems, the so-called embedded beam elements (EBE) have recently been devel-oped. In a preceding contribution of the authors, an improved EBE formulation,which brings into play the soil-pile interaction surface, was proposed with theaim to localize material plasticity in the soil surrounding the pile. This embed-ded beam model couples two different finite elements, each described by distinctkinematics (ie, solid and beam). The coupling is incorporated in the formulationby means of kinematical constrains established over the solid and beam dis-placement fields on the interaction surface. One of the main advantages of theembedded elements is that the addition of beams structural members immersedwithin the 3D soil model does not represent a constraint for the solid mesh,which can be adopted independently from the beam mesh. In this paper, the lat-eral loading of pile groups is studied by means of the proposed EBE approachwith elasto-plastic interfaces. In order to represent a rigid cap, a master node anda special set of kinematical restrictions are incorporated into the formulation.The paper presents results obtained by means of the present formulation com-pared against other well-established analysis methods and test results publishedin the literature, for both elastic and elasto-plastic cases.