A geostatic analysis is performed for both Case 1 and Case 2 to ensure that equilibrium is satisfied between the initial state and self-weight within the clay layer.
At the end of the geostatic analysis, the total deformation should be zero, confirming that equilibrium is satisfied. All embankment layers and contact elements must be deactivated and displacement of the nodes attached to those elements in Y direction must be constrained.
Example 52.2: Geostatic Analysis
ANTYPE,SOIL ! Activate soil analysis SSOPT,GEOSTATIC ! Select geostatic step TIME,35 ! Set time at the end of geostatic step NSUBST,1 ! Set number of substeps to 1 AUTOTS,ON ! Enable automatic time-stepping SOLVE ! Solve
The next eighteen steps for Case 1, and the next three steps for Case 2, are consolidation steps, each step corresponding to the activation of a specific embankment layer.
Along with reactivating the appropriate elements, the displacement restriction in the Y direction for the nodes attached to them is removed.
For Case 1, the command for reactivating contact pairs (EALIVE) appears only in steps 2, 8 and 14.
Example 52.3: Consolidation Analysis
SSOPT,CONSOLIDATE ! Activate consolidation analysis TIME,1.5*24*3600 ! Set time at end of consolidation ! (Case 1 is 0.25 days. Case 2 is 1.5 days.) DELTIM,20,0.5,1E4 ! Define time-increment values AUTOTS,ON ! Enable automatic time-stepping SOLVE ! Solve
Excess pore pressure is the pore-pressure increase in excess of the initial state pore pressure when a saturated soil is loaded. Because the excess pore-pressure evolution must be checked, that data is output for postprocessing (ETABLE,SADD) .