Groundwater Seepage Analysis Overview

Within the Slide program, Slide has the capability to carry out finite element groundwater seepage analysis for steady state or transient flow conditions. NOTE:

In order to use the Slide program for a groundwater analysis, the following general procedure is required.

Project Settings

In order to perform a groundwater seepage analysis, you must first define the groundwater project settings. You can choose steady state analysis, transient analysis or both steady state and transient.

  1. Select Project Settings from the toolbar or the Analysis menu.

  2. Select the Groundwater page in the dialog.

  3. Select OK and the Slide toolbar will display an Analysis Mode option as described below.

If you have chosen both steady state and transient analysis, the steady state analysis results will define the initial groundwater conditions for the transient analysis.

Groundwater Analysis Mode

When you choose either steady state or transient groundwater in Project Settings, you will notice an option in the Slide toolbar which allows you to switch between different analysis modes – Slope Stability, Steady State Groundwater or Transient Groundwater.

The Slope Stability mode allows you to define the elements of your model which are relevant to the slope stability analysis. The Groundwater modes (steady state or transient) allow you to define the elements of your model which are relevant to the groundwater analysis.

When you switch between Slope Stability and Groundwater modes, you will notice that the menus and toolbars are automatically updated so that the appropriate modeling options are available. See the Groundwater Analysis Mode topic for details.

Boundaries

The SAME boundaries are used in both the groundwater and slope stability analysis. However, the model boundaries can only be defined when the analysis mode = Slope Stability.

See the topics in the Boundaries section of this Help system, for full details about defining and editing model boundaries in Slide.

Meshing

The groundwater analysis in Slide is a finite element analysis, and therefore a finite element mesh is required in order to solve the problem.

To create the finite element mesh:

Groundwater Boundary Conditions

Once the finite element mesh is satisfactory, you must then define the boundary conditions of the groundwater problem you wish to solve. This is done with the Set Boundary Conditions option or Set Transient Boundary Conditions option, which allow you to define the groundwater boundary conditions (e.g. head, pressure, infiltration, flow) along the model boundaries.

Groundwater Material Properties

The permeability (hydraulic conductivity) characteristics of each material are defined with the Define Hydraulic Properties option. You may define a saturated permeability for each material, and various models are available for defining the unsaturated permeability.

Groundwater Compute

When all of your groundwater boundary conditions and material properties have been defined, then you are ready to run the groundwater seepage analysis. To run the analysis:

After you have computed the groundwater analysis, you should view the results of the groundwater analysis, by selecting the Interpret Groundwater option.

If the groundwater analysis results are satisfactory, then you can return to the Slide Model program, switch the Analysis Mode = Slope Stability, and proceed with your slope stability analysis.

When you select the slope stability Compute option, the slope stability analysis will automatically use the pore pressures calculated from the groundwater analysis.

Groundwater Interpret

The Groundwater analysis results are viewed in the Slide Interpret program, and can be viewed simultaneously with the slope stability analysis results. For information, see the Groundwater Results Overview topic.

After you perform a groundwater analysis with Slide, it is always a good idea to first use the Interpret program, to check that the groundwater analysis results are reasonable. If not, then you should go back to the Slide Model program, and check that you have defined your model correctly.