Numerical studies on the use of zero thickness interfaces in cyclic soil structure interaction analysis

In FE analyses interfaces are crucial for the adequate modelling of the soil structure interaction (SSI). In this paper zero thickness interfaces modelled with varying constitutive models and interface properties are evaluated for cyclic SSI problems with primarily lateral loading. Therefore, a simplified 2D FE model is used that simulates the cyclic seasonal temperature deformation of an integral bridge abutment. Linear elastic and elastoplastic constitutive models are applied for the interface and soil. The study reveals that zero thickness interfaces subjected to large lateral loading can cause interpenetration effects that
significantly influence the mobilised earth pressures in the adjacent soil. When modelling interfaces by means of constitutive models with stress-dependent stiffnesses these effects can be amplified with increasing cyclic loading. The underlying causes for these effects are explained and different approaches are investigated to reduce the obtained effects. Comparisons are drawn
to calculations without interfaces and with thin layer continuum interfaces.