Increase of stiffness in the Mohr-Coulomb Material Model

Hi all,

I am running into trouble with the increase of stiffness in the Mohr-Coulomb Material Model. I am using Plaxis 3D conect Edition V21.

The increase in stiffness in the Model is linear, while my stiffness is parabolic. Is there a way to adapt a parabolic change into the Mohr-Coulomb Model or is there a Material Model where the stiffness can change in parabolically over the depth?

Thank you for your time


  • Jesco,

    You could do it by developing your own user defined version of the MC model, but this is a very advanced undertaking, and I wouldn't do it unless I was working on a PhD which required it, and I had a lot of spare time to test it. The HS model has a power law stress dependent stiffness. However the stress stiffness would change  during your analysis and probably not what you're looking for. You could use the brute force method of defining  a series of horizontal layers and assigning MC materials to each layer with parabolically increasing stiffness.

    Maybe someone else had some better ideas. 


    Answer Verified By: Dennis Waterman 

  • Dear

    I agree with Martin there. The only idea I could come up with is identifiying numerous horizontalm layers and increase the modulus manually by changing the value. However, in plaxis 3D beware of the size of  the mesh and the width of your model. If your model is very wide, then introducing very thin layers can lead to small finite elements being introduced and thus, you might have some mesh issues.

    Good luck.