This paper presents background information relevant to the modelling of soil-structure interaction. The interaction between the structural element (i.e. pile foundation or abutments) and the soil medium is believed to have the potential to alter considerably the actual behaviour of any structure. Modelling of the structural element is rather simple and straightforward when compared to modelling the structure in interaction with soil. It is known that the structural analysis simplifies soil behaviour, while geotechnical analysis simplifies structural behaviour. The choice of an appropriate soil constitutive model may have significant influence on the accuracy of soil-structure interaction analyses. A 2D finite element analysis on a pile-cap-pile-soil model replicating actual field work was performed in this paper using OASYS SAFE to further substantiate the choice of an appropriate soil constitutive model for the purpose of soil-structure interaction modelling.