When selecting the “2D | Constrained Modulus Method (Elastic Half-Space)” type of soil representation, springs are created at the foundation base to simulate the bedding stiffness of the soil defined in situ. After selecting this type, additional settings appear to define the 2D soil parameters. The following image shows the input dialog box with the numbered options.
Selecting Surfaces
You can enter surfaces where the supports are to be placed in the text box or select them graphically using the button next to the text box. Additionally, you can select the “Automatic detection” check box to have RFEM detect the surfaces to be supported.
Generating Supports
The following point specifies for which support types (nodes, line, and surface supports) should be spring stiffnesses generated. Currently, the Surface and Line base types are set here.
Background information on the constrained modulus method and the determination of edge springs is provided in the corresponding section of Theoretical Principles.
Nonlinearity / Failure under tension
By selecting this check box, nonlinearities are assigned to the generated support conditions, which lead to failure under tension perpendicular to the supported surface.
Spring constants in horizontal direction
The text boxes assigned to this point define the translational elastic constants in the horizontal direction that are assigned to the generated support conditions.
Rock beneath the last layer
This button controls the approach of an incompressible layer below the last soil material, which was defined using the borehole or soil solid. This sets a fixed maximum limit depth for the calculation of the foundation parameters.
Generated Supports
The following image shows an example of the supports generated from the settings of the 2D soil parameters.
