Because the solid deformation of the matrix due to pore-pressure depletion is a coupled analysis, a soil analysis (ANTYPE,SOIL) is performed using the consolidation option (SSOPT,CONSOLIDATION). Automatic time-stepping is enabled (AUTOTS,ON). and time-integration for structural degrees of freedom is disabled (TIMINT,OFF,STRUC). The global stiffness matrix is unsymmetric, so an unsymmetric Newton-Raphson solver option is necessary (NROPT,UNSYM).

The following input sets up the analysis:

ANTYPE,SOIL
SSOPT,CONSOLIDATION
TIMINT,OFF,STRUC
NROPT,UNSYM
AUTOTS,ON
NSUBST,10,10000,1