GeoStudio | PLAXIS - Replacing a LE or MC material set with an advanced material set unexpectedly gives OCR = 1.25

Application	PLAXIS 2D
Issue status	✔ Solved
First Affected Version	PLAXIS 2D AE.00
Found in Version	PLAXIS 2D AE.00
Fixed and Released in Version	PLAXIS 2D 2015.00
Issue #	22202
Date created	30 October 2014
Date modified	24 October 2016

Problem description

When replacing a material set that does not allow for input of an overconsolidation (like the Linear Elastic (LE) model or Mohr Coulomb (MC) model) with an advanced model that allows for input of an overconsolidation (like for example the Hardening Soil (HS) model) in PLAXIS 2D AE, the (isotropic) overconsolidation ratio OCR gets “automatically” initialized at a value of 1.25. Note that:

even when the advanced model has an input value of OCR = 1 this happens;
the (horizontal stresses) are not influenced by this automatic OCR value of 1.25, only the
preconsolidation stress p_p is influenced;
the (isotropic) OCR value can be viewed in Output via the menu Stresses > State parameters > OCR.

This behaviour is unexpected and may lead to unrealistic results.

Solution

This issue is now solved since PLAXIS 2D 2015.00: the OCR for these clusters is now initialized at 1.0

For PLAXIS 2D AE there is no work around possible other than trying to prevent this situation.