Transient Groundwater
To model time-dependent (transient) groundwater seepage analysis, the general procedure is the same as outlined for the Steady State groundwater seepage analysis, with the following additional steps.
Project Settings
You must set the Groundwater Method = Transient in the Project Settings
dialog.
On the Solver Options page of the Project Settings dialog, you can choose:
- Analysis Type: Coupled (Biot) or Uncoupled
On the Units page of the Project Setting dialog, you can choose:
- Time Units
- Permeability Units
On the Stages page of the Project Settings dialog:
- you must enter a time for each stage
- you can also define the method of initial pore water pressure calculation (optional)
Hydraulic Material Properties
In the Define Hydraulic Properties
dialog you can define the permeability characteristics of your materials for groundwater seepage analysis, including additional parameters required for the transient analysis (e.g. water content curve).
TIP: the Hydraulics tab can also be accessed directly from the Material Properties dialog.
Groundwater Boundary Conditions
The hydraulic boundary conditions for seepage analysis are defined with the Add Groundwater Boundary Conditions
option in the Groundwater menu. For transient analysis you can define time-dependent boundary conditions (e.g. total head versus time, infiltration versus time, etc.).
Discharge Sections
To compute the flow volume across a surface use the Add Discharge Section
option in the Groundwater menu to define a discharge section.
Compute
To compute the seepage analysis only (without computing the stress analysis), you can use the Compute Groundwater
option. This allows you to view and verify the seepage analysis results, before proceeding to the stress analysis.
The main Compute 
option will compute both seepage and stress analysis.
Groundwater Results
After computing a transient seepage analysis you can view contours of groundwater results at each stage (time) including pore pressure, total head, hydraulic gradient, velocity etc. If discharge sections were defined you can view the volumetric flow rates across any surface. Other results such as flow vectors can be displayed.