When using a PLAXIS 2D version without a Dynamics licence the gravity input field in the general properties window is not shown (and thus not editable). This is done since the gravity value is only relevant for full dynamic calculations. Input for non-dynamic calculations is the volumetric weight of soil and water in which the gravity is implicitly included. Note that also for pseudo-static calculations the gravity value is not relevant since the kernel uses the ratio between the gravity acceleration (= 1G) and the specified “gravity acceleration+additional acceleration” to scale up volumetric weights.
Now when setting up a project with a PLAXIS 2D version without a Dynamics licence and switching to non-metric units, internally in the program the gravity value is kept as 9.8, which is only valid in the metric units system (9.8 m/s2). This value of 9.8 is also the value that is shown in the Output program together with the selected (non-metric) units, which is obviously not correct. But as mentioned above this has no influence on results since the gravity value is not used directly in non-dynamic projects.
Note however: when setting up a project with a “version without a Dynamics licence” and continuing this project in a “version with a Dynamics licence” and actually performing a full dynamic calculation be sure to explicitly check and adjust, if necessary, the gravity value shown in the general properties window in Input.
Since PLAXIS 2D AE.00, the gravity value is a fixed value of 9.8 m/s2 and will be converted correctly to the used units in the PLAXIS 2DAE project.