When defining the Initial Phase as a gravity loading phase, any prescribed displacement activated in any later phase will not be applied correctly in PLAXIS 2D AE: the prescribed displacement value will result in a value of zero (i.e. equal to the setting Fixed).
This does not happen when having the K0 procedure as calculation type for the initial phase: then the correct defined prescribed displacement value is used in the calculation.
This issue is now solved since PLAXIS 2D 2015.00
In PLAXIS 2D AE, the only possible way to use a prescribed displacement with an actual prescribed value for the displacement is to use a K0 procedure. In most cases this will require a plastic nill step (a plastic phase without any change in the model) to be performed directly after the K0 procedure, followed by a check on the stresses in the model for this nill step. These should be equal to the stresses of a gravity loading.