Hello everyone,

I am modeling a pile-soil interaction using ABAQUS. In my model, the pile is subjected to a harmonic lateral load at the head. I use infinite elements at the boundaries. As I need to reset the displacements to zero before applying the harmonic load on the pile, I create two models. In the first one, the geostatic stresses and the weight of the pile are applied.
In the second model, the induced stresses (from the first model) are transferred (as initial stresses). Then a static step is created for achieving the equilibrium. In this step, the weight of the pile and the soil (just for the finite elements) are applied. After this static step, there is a dynamic step in which the harmonic load in applied at the pile head.

When the model runs, from the first time instance in dynamic model, the infinite part has a upward movement. It is unrealistic as the infinite elements are supposed to behave as the far field.

I really appreciate any help in figuring out the problem in my model.