By applying interface elements PLAXIS users can simulate the interaction between a structure and soil. While without an interface no relative displacement (slipping/gapping) will be possible between structure and soil.
When interface applied, node pairs will be created at the interface of structure and soil. Each node pair consists of two nodes – one belongs to the structure and the other belongs to the soil. The interaction between these two nodes consists of two elastic-perfectly plastic springs. One elastic-perfectly plastic spring to model the gap displacement and one elastic-perfectly plastic spring to model slip displacement.