Problem description

While drawing a closed flow boundary in PLAXIS 2D AE Water Conditions mode, a thick, black line should appear at these model boundaries:

Figure 1: Closed flow boundary on the left (thicker black line)

However, in PLAXIS 2D AE.00 this closed groundwater flow boundary condition will not be activated automatically right after drawing and so no thick black line will be shown. This means that it is also not active, and so not closed, for the calculation. For this closed flow boundary to be activated, it needs to be activated manually before it acts as a closed flow boundary during the calculation.

Also, when selecting this boundary condition, its setting will not become clear from the Selection explorer in Water Conditions mode.

Solution

This has been solved in PLAXIS 2D AE.01:

• While drawing a closed flow boundary in PLAXIS 2D AE.01, this closed flow boundary will be activated and a thick black line should appear
• Explorers in water conditions mode can be used to activate or deactivate without going to the Staged construction mode

To activate this closed flow boundary in PLAXIS 2D AE.00, two options are available:

1. After drawing it as a closed flow boundary, right click on the closed flow boundary in the model, and then select to activate it:
   
   Figure 2: Right click to activate the groundwater flow boundary condition
2. For the second option, you should go to the Staged Construction mode (for the same phase) and then click on this boundary in order to select it. In the selection explorer, you  can now see the setting of this boundary condition, e.g. as below with an active and closed groundwater flow boundary condition (here: GWFlowBaseBC_2). When the GWFlow-item is not checked, it will mean that it is not activate, and the behaviour setting will not be taken into account: it will not be closed during the calculation.
   
   Figure 3: Activate the boundary condition in Staged Construction

Another way to work around this, is to use the Model Conditions > GroundwaterFlow from the Model Explorer. If no line-specific flow boundary conditions are defined, these settings can close an entire model side for groundwater flow and consolidation, but be aware that no graphical indication is given that the boundaries are closed (e.g. no thick black lines).

Figure 4: Closed flow boundary conditions in Model Conditions