https://communities.bentley.com/products/geotech-analysis/f/forum/222945/increase-of-stiffness-in-hardening-soil-with-undrained-bHi PLAXIS team, Reading from PLAXIS manual, I see the following and agree with it. &quot;PLAXIS has options to deal with undrained behaviour in an effective stress analysis, the use of undrained shear strength (cu or Su) may be preferred over the use ofen-USTelligent Community 12https://communities.bentley.com/thread/685580?ContentTypeID=1Sat, 04 Dec 2021 12:41:41 GMT6dad98f5-dbc9-4c4d-a9ba-e9da8dc6aa8e:9170410e-2b5e-4dd6-ae48-0dad3360a1f4Omar Mahdy<p>Dear James,</p> <p>Unfortunately, this is not possible since the pressure dependency of stiffness formula depends mainly on the friction angle which in Undrained B case is zero. So the stiffness will be constant no matter what.</p> <p></p> <p>Regards,</p> <p>Omar</p><div style="clear:both;"></div>