Problem description

[UPDATED] 
All issues are now solved in PLAXIS 2D CONNECT Edition V22 Update 2 and PLAXIS 3D CONNECT Edition V22 Update 2 (released October 2022). Please refer to the bullet list below for more information.

With the introduction of the uniform unit system in PLAXIS CONNECT Edition V22.00, PLAXIS is now internally using a specific set of units (internal storage unit system) regardless of the project units selected in the project (presentation unit system). This allows the calculation to handle project data in the same way regardless of the project units selected, thus ensuring consistency. Therefore, the project units are only used by PLAXIS Input and Output programs to display the input data and computed results.

In PLAXIS 2D/3D CONNECT Edition V22.00 an issue was identified regarding the displayed values and concerning units of a limited set of Output results. This occurs when using project units that are different from the specific set of units (internal storage unit system) PLAXIS considers.

Results included in soil/structure plots, such as the deformations, stresses, strains, pore pressures and forces remain correct regardless of the project units selected.

The internal storage unit system PLAXIS uses for calculations is the following:

Figure 1. PLAXIS 2D project units	Figure 2. PLAXIS 3D project units

For all other unit combinations, even though the calculation results are correctly computed, the values displayed in PLAXIS Output could be incorrect for the few cases explained below, which can lead to an incorrect interpretation of the results.

We have seen this issue occurring in the following cases (note that the relevant unit that causes the issue is added in parentheses):

• Tables: Node/stress point coordinates (unit of length) - Fixed in PLAXIS 2D/3D CONNECT Edition V22 Update 1
• Cross sections:  - Fixed in PLAXIS 2D/3D CONNECT Edition V22 Update 1
  • Equivalent force for soil cross sections (unit of length)
  • Total discharge results for soil and interface cross sections, as shown in the title below the groundwater/heat flow results plot (unit of length)
  • Cross section curves (unit of length)
  • linecrosssectionplot command: length parameter (unit of length)
• Structures view: Total discharge results for interfaces/discontinuities, as shown in the title below the flow results plot (unit of length, unit of time)  - Fixed in PLAXIS 2D/3D CONNECT Edition V22 Update 1
• Centerline force calculations: Structural forces in volume plates/piles (unit of length)  - Fixed in PLAXIS 2D/3D CONNECT Edition V22 Update 1
• Coordinates on status bar: mouse position coordinates on the bottom status bar for soil and structure cross section plots, and structures plots in PLAXIS 3D (unit of length)  - Fixed in PLAXIS 2D/3D CONNECT Edition V22 Update 1
• Hint window: Node/stress point coordinates (unit of length)  - Fixed in PLAXIS 2D/3D CONNECT Edition V22 Update 1
• Distance measurement tool (unit of length)  - Fixed in PLAXIS 2D/3D CONNECT Edition V22 Update 1
• Forces View: in PLAXIS 2D, under Tools menu (unit of length, unit of force for stresses)
• Deformed shape plots: default scaling value provided (unit of length)
• Fixed-end anchor forces: in PLAXIS 3D, pop-up window (unit of force)
• Import tabulated data consider SI units (e.g., N, m) instead. This concerns:
  • Plate with Material type set to Elastoplastic (Μ-κ)
  • Geogrid with Material type set to Elastoplastic (N-ε)
  • Embedded beam with/without Material Type set to Elastoplastic (M-κ), Multi-linear axial skin resistance and/or lateral resistance (2D only)
  • Temperature dependent table in Project properties, Constants tab (2D only)
  • Unfrozen water saturation table in Soil material data set, Thermal tab (2D only)

Workaround/Solution

Most issues are now solved in PLAXIS 2D CONNECT Edition V22 Update 1 and PLAXIS 3D CONNECT Edition V22 Update 1 (released May 2022). Please refer to the bullet list above for more information.

For older versions and/or unresolved issues, users are advised to switch the project units to the following recommended units (internal storage unit system) shown below and reopen Output to view the results. Please note that it is not required to re-calculate the project.

Any saved cross section curves, reports, or saved views are required to be re-created. This will ensure that the results and the corresponding units are correct.

Figure 3. PLAXIS 2D recommended units

Figure 4. PLAXIS 3D recommended units

To change the project units, follow the steps below:

1. Load the PLAXIS project in Input program.
2. [Optional] Use the File > Save as option for backup purposes.
3. Click the Project properties button or go to File > Project properties… option – see Figure 5.
4. Change the units to the recommended ones.
5. View the results in the Output program.
   It is not required to re-mesh or re-calculate the project.

Figure 5. Project properties button in the toolbar