Problem description

In the 2D2010/2D2011 Advanced Mode, in a Consolidation TPP phase, activating a cluster and changing its water conditions in the same phase will result in unexpected pore pressures.

The reason for this is that when activating any cluster in a Consolidation TPP analysis, its bulk modulus of water is initially low and this will not allow for a lot of groundwater flow.
See also page 251 of the report Groundwater flow, fully coupled flow deformation and undrained analyses in PLAXIS 2D and 3D by V. Galavi (2010).

Solution

Tsis issue is now solved with the release of PLAXIS 2D AE.

For older versions, a workaround is available that should be done in two phases:

• first insert a phase prior to this Consolidation TPP phase to construct the layer: this can be a Plastic calculation or a Consolidation TPP phase:
  • For a a Plastic phase, the cluster should be activated. One can choose a time interval of zero or how long the construction of the soil layer takes. No other changes are yet required.
  • For a Consolidation TPP analysis, the time it takes to construct the soil layer can be taken into account as well.
• second step: using a Consolidation TPP calculation. All parameters can be set as in the original (single) Consolidation TPP phase.