When using the updated mesh feature in combination with updated water pressures in PLAXIS 2D2011, and deactivated clusters are present beneath the general phreatic water level, wrong water loads are calculated within these deactivated clusters. The resulting external water loads on the adjacent active cluster boundaries are now taken into account two times (both in horizontal and vertical direction).
Note that this issue does not directly become clear from the Output program (the “normal” external water loads are shown). However when looking at the effective and/or total stresses you will notice that the external water loads are too high. This is also shown in the example below:
Please note that this is only the case for deactivated clusters that are initially beneath the general phreatic water level. External water loads in deactivated clusters that during the calculation “settle” beneath the general phreatic water level are OK.
There is no workaround possiblein 2D2011.01
The issue is fixed in PLAXIS 2D2011.02.