Problem description

In the Groundwater tab of the Soil dataset, we can choose between different settings to give default permeability values:

• None, to define your own hydraulic conductivity values
• From data set
• From grain size distribution

The permeability values used for the last two can be found in the PLAXIS Reference manual in the sections about Hydraulic datasets and models and Saturated permeabilities.

When you change the option Use defaults for an existing dataset from From data set to None, the values for k_x, k_y and k_z (3D only) are internally not updated but kept at the same values when using a PLAXIS CONNECT Edition V20 Update 1 or earlier. This also means that the calculation will take the earlier permeability settings as defined in the From data set configuration.

The changes are stored correctly when you e.g. create a new material dataset, when you change the Use defaults to From grain size distribution, or when you change from From grain size distribution to None. This issue only happens when you change the Use defaults from From data set to None for an existing material dataset.

Solution

The issue has been resolved since PLAXIS 2D CONNECT Edition V20 Update 2 (20.02.00) and PLAXIS 3D CONNECT Edition V20 Update 2 (20.02.00) 

For older versions, please check the material set’s permeability settings.

When the hydraulic conductivity values k_x, k_y and k_z (3D only) are not updated to your values, please follow these steps:

• Open the material dataset and go to the flow parameters tab sheet
• Verify the Flow parameters settings. When still set to From data set:
• Change the Use defaults value to From grain size distribution
• Click OK to make the changes
• Reopen the dataset
• Now set the Flow parameters – Use defaults value to None
• Fill in the hydraulic conductivity values k_x, k_y and k_z (3D only)
• Click OK to accept the changes

This will store the hydraulic permeabilities correctly.

See also the attached video