As I understand the Biot coefficient is supposed to be set by setting elastic parameters and solid grain bulk modulus (*POROUS BULK MODULI). I made a simple test to check the effective stresses which Abaqus outputs. A cube with constant pore pressure has symmetrical boundary conditions on x=0, y=0, z=0 planes and constant surface pressure on opposing sides. What you get when Biot coefficient equals 1 is S11=S22=S33=(Surface pressure)-(pore pressure). Then I set the solid grain bulk modulus to some amount so I get the Biot coefficient I want to set for the material (equation looks like (biot_coffecient=1-(material_bulk_modulus)/(grain_bulk_modulus)). Then I want to see the results as S11=S22=S33=(Surface pressure)-(biot_coefficient)*(pore pressure). However the stresses don't change at all with various grain bulk modulus. Previously I used ANSYS and I solved the same problem there and got the results I expected. I attach the generated .inp-file - https://pastebin.com/w5yQJcsq

What's wrong with this solution?