A special feature exists for the simulation of the building process. This procedure allows for a realistic assessment of stresses and displacements as caused, for example, by the construction of an earth dam or an excavation for a deep basement. The option staged construction is also used to activate a change in the pore pressure distribution. 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.
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. 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.