Hi,  i need to simulate an experiment for my University in which a slice of a mountain is taken in which a tunnel is excavated. I remember that there was an option to "remove" or "deactivate" regions or cells but i cannot find it anymore. I dont just want to remove the inner part for good. I want to remove it in step 2 and ad it back in again in step 3 when the surrounding rock has converged a bit and is in equilibrium.  I have to use Abaqus 2020. Can someone help me there?

Best Regards