Phreatic model

I have SS model with 5 layers: phreatic, unspe., unspe., unspe., unspe., fixed modes. The simulation result for the first slice shows head larger than topography. How can this happen in FEFLOW?

By default, FEFLOW does not limit the head to the top slice elevation. Please check out the options in the free-surface settings to get an overview of the possible restrictions.

Thank you that answers my question.

This topic is very interesting because I built several model and it's not obvious to decide if we fix the slices. I worked on a model recently and everything was free and movable. So the calibration was almost perfect but the geometry of the model was consedirably modified. The variation was so big that It was almost unsensed to consired that model appropriate.

There are rules to define when we should use Fixed or Free and movable ? I always used fixed in my models because of the geometry but I don't know if I'm OK.....

Regards