coupled pore fluid and stress problem

[sergini]

Hello,

I am modeling compaction/subsidence phenomenon with SOILS routine in ABAQUS. The geometry is an elliptical reservoir. I applied boundary conditions (prescribed displacement magnitude) and initial conditions (initial pore fluid pressures, void ratios and stresses). The first step of the analysis is an optional step to ensure an equilibrium geostatic stress field (geostatic stress to balance gravity loading). However, outputs are not correct and I obtained strains in the order of 10-4 and displacement in the order of meters. If anyone has experience with these types of problems, please let me know.

Thanks
…
**-------------------------------------------------------
**
** BOUNDARY CONDITIONS AND INITIAL CONDITIONS
**
**-------------------------------------------------------
*BOUNDARY
N-SURFACE, 8,,0.
*INITIAL CONDITIONS, TYPE=STRESS, GEOSTATIC
EL-OVERBURDEN, 0.00, 6096.00, -32228917.26, 3048.00, .8, .8
EL-SIDERBURDEN,-32228917.26, 3048.00, -32551206.43, 3017.52, .8, .8
EL-RESERVOIR, -32228917.26, 3048.00, -32551206.43, 3017.52, .8, .8
EL-UNDERBURDEN, -32551206.43, 3017.52, -64457834.52, 0.00, .8, .8
*INITIAL CONDITIONS, TYPE=RATIO
N-OVERBURDEN, 0.1111
N-SIDERBURDEN, 0.1111
N-RESERVOIR, 0.4286
N-UNDERBURDEN, 8.1661e-03
*INITIAL CONDITIONS, TYPE=PORE PRESSURE
N-OVERBURDEN, 0.00, 6096.00, 29900880.00, 3048.00
N-SIDERBURDEN, 29900880.00, 3048.00, 30199888.80, 3017.52
N-RESERVOIR, 29900880.00, 3048.00, 30199888.80, 3017.52
N-UNDERBURDEN, 30199888.80, 3017.52, 59801760.00, 0.00
**
**-------------------------------------------------------
**
** Step 1: GEOSTATIC STEP TO BALANCE GRAVITY LOADING
**
**-------------------------------------------------------
*STEP
*GEOSTATIC
*DLOAD
EL-OVERBURDEN, GRAV, 9.81, 0, 0, -1
EL-SIDERBURDEN, GRAV, 9.81, 0, 0, -1
EL-RESERVOIR, GRAV, 9.81, 0, 0, -1
EL-UNDERBURDEN, GRAV, 9.81, 0, 0, -1
*BOUNDARY
N-BASE, 3, 3
SYMMETRY-X, 2, 2
SYMMETRY-XYZ, 1, 1
SYMMETRY-XYZ, 2, 2
SYMMETRY-XYZ, 3, 3
**
** OUTPUT REQUESTS
**
*Restart, write, frequency=1
**
** FIELD OUTPUT: F-Output-1
**
*Output, field, frequency=99999
*Element Output
E, S, VOIDR, POR
*NODE OUTPUT
U, POR
**
** HISTORY OUTPUT: H-Output-1
**
*Output, history, variable=PRESELECT
*El Print, freq=999999
*Node Print, freq=999999
*End Step