Dear All,
I have a Plaxis 3D model in which the ground surface is a slope replicating the real topography (modelled using point cloud). Is there a way to assign E' and c'/Su increase with depth (not with level) in the Plaxis 3D model? Assigning E' and c'/Su increase with level for a slope generates unrealistic soil properties for soils in the bottom part of the slope if level (Zref) is choosen say at mid height slope.
Thank you.
Kind regards,
Victor
I agree with you, I am having the same issue but with PLAXIS 2D.
What soil model are you using? The Hardening Soil allows the variation of stiffness based on stress level.
However, I am still stuck on how to vary the strength accordingly.
Dear Victor,
It is possible to have E', c', and Su increase by the depth in Mohr-Coulomb soil model. You can go to advanced option in soil parameters input. In Hardening Soil, you can also use the strength increase by the depth using this way.
James, I am using the M-C model. You are right that it can be done using the HS model, but for this you need calculate the soil stiffness with depth baed on the forumlation (formulas provided in the Plaxis manual), which is quite tedious.
Hi Ari. I am affraid this works only when you have a flat ground / strata level. If you use this option in a model with sloping ground / strata then you will obtain overprediction of soil properties for soils in the bottom part of a slope if Zref is choosen at mid height of slope.
There is no direct way to input E' and su increasing with depth, but for undrained shear strength it is possible to let PLAXIS determine the increase of shear modulus and undrained shear strength at the beginning of the calculation (so at the start of the first phase for instance) using the SHANSEP Mohr-Coulomb model. It will calculate the undrained shear strength based on the current stress state, and with a user-specified constant ratio of G/su the stiffness is calculated accordingly.
https://communities.bentley.com/products/geotech-analysis/w/plaxis-soilvision-wiki/46110/udsm---shansep-mc-model
With kind regards,
Dennis Waterman