In some cases when using a PLAXIS 3D 2013 model or using imported geometry in PLAXIS 3D AE.00, it can happen that the default boundary conditions are not applied correctly, which results in missing fixities on the boundaries.This of course will not give the expected results of an analysis.
You can see this happening when inspecting a phase’s preview or its results:
Figure 1. Example of missing fixities (left) and unexpected waterloads (right)
This issue has now been fixed in PLAXIS 3D AE.01.
When the above happens in a PLAXIS 3DAE.00 model, it can be solved by creating a surface prescribed displacement on the entire troubling side, and set the boundary conditions manually, for example:
Do not forget to activate this manual boundary condition (the surface prescribed displacement) in your phases.