Numerical Modelling of Passively Loaded Pile Groups

Piled foundations could be affected negatively as a result of passive loadings caused by nearby soil movement-induced activities, and failure of piles could happen in some sever cases. This paper deals with the numerical analysis of passively loaded pile groups and piled raft in sand. The complexity involved in such problems due to pile-soil, pile-pile, pile-cap, soil-cap, and moving soil-stable soil interaction needs a powerful tool to make three dimensional analysis possible. In the current study, PLAXIS 3D software was used to back analyse laboratory tests carried out by the authors. Embedded pile feature in which the pile is represented by beam elements, while soil-pile interaction along the pile shaft and at the pile tip is described by special interface elements was employed. The Mohr-Coulomb elastic-plastic constitutive model was used to describe the sand behaviour. Although an overestimation of the predicted deflection was obtained, the general trend of bending moment profiles of piles was in a reasonable agreement with those obtained experimentally. A number of limitations were identified as possible reasons behind the overestimation of the predicted deflections. Furthermore, parametric studies are adopted to consider the effects of pile diameter, pile-soil stiffness and pile group configuration on the response of passively loaded pile groups.