Sheet pile walls are usually discretised with structural elements (beam or shell elements). This type of discretisation can lead to problems if under vertical loading a signi ficant part of the load is carried via the base of the wall. In the case of individual sections, an extension of interface elements can be taken into consideration at the base of the wall so that the sheet piling section can penetrate into the ground and no unrealistic stress peaks can occur in the body of soil below the base of the wall – see recommendation E4-15 in (S CHANZ, 2006). In the case of combined sheet pile walls under vertical loading where significant bearing pressures are mobilised, a bearing pressure can be modelled with the help of a stiff transverse beam at the base of the wall (MEISSNER, 2002).
In the case of a staggered sheet pile wall, the 2D equivalent model must take into account the fact that the base of the equivalent wall is permeable.
Where possible, the force transfer between sheet pile wall and soil should be modelled with interface elements or by way of kinematic contact formulation. This guarantees that no tensile stresses are transferred along the sheet pile /soil boundary surfaces and that, with corresponding action effects, irreversible sliding between sheet pile wall and soil can take place. Bilinear contact and friction principles are used for this in the simplest case.