applying geostatic stability

[wan8]

hi every one.
i wonder about soil stability ,
by using the initial stresses in geostatic step and applying the gravity loads in & by using finite element 3d soil model .
so i prevent movement in the vertical direction at bottom.
the proplem is ,
when the geostatic step runed i found a deformation (u3)
in the top layer of the model and all this befor loading (just the soil weight by gravity)
so i want to reach the stability state with zero deformation after geostatic step to consolidate the soilafter that by loading.
i'm waitting your advise.
wan

 

[wan8]

how are you all
could any one give me an idea of how to start soil model with initial stresses and zero deformation by geostatic step,
thanks
wan

 

[slam00000]

Just try to calculate approximately (manually) the initial stress field resulted from the gravity force. And then invoke the command *Initial Stress Geostatic via the keyword editor using the values of the stress you calculated.