Horizontal Stress in one-dimensional loading by Cam-Clay Model

Hi everyone,

I am trying to simulate a cylinder filled material with a vertical one-dimension loading using Cam-Clay model in 2-D axisymmetry. I have been following the "Isotropic Compression" provided example, but only applying vertical load.

My question is: Does cam-clay model in COMSOL compute the mean effective stress considering the horizontal stress (defined by K0 value)? Or is the mean effective stress calculated considering zero horizontal stress (since I have not defined any horizontal stress boundary load)?

If it's the second case, what are your suggestions on implementing the horizontal stress from the earth pressure constant? Thank you!

Sina