The option staged construction is also used to activate a change in the pore pressure distribution. For some situations, a conventional small strain analysis may show a significant change of geometry. In these situations it is advisable to perform a more accurate Updated Lagrangian calculation, which is called an Updated Mesh analysis in Plaxis. The decay of excess pore pressures with time can be computed in a consolidation analysis. A consolidation analysis requires the input of permeability coefficients in the various soil layers.
Automatic time stepping procedures make the analysis robust and easy to use.
This definition is suitable for foundation structures, but not for embankments and sheet-pile walls. For this latter type of structure it is more appropriate to use the soil mechanics definition of a safety factor, which is the ratio of the available shear strength to the minimum shear strength needed for equilibrium. In Plaxis the factor of safety is computed using a 'phi-c reduction' procedure. Exact values of displacements, stresses and structural forces can be obtained from the output tables. Graphs in full color and tables can be send directly to any Windows supported printer or plotter, or to the Windows clipboard for import into spreadsheets, word processors or other software.