Distributed loads (i.e. tractions) can be applied to a Slide model with the Add Distributed Load option in the Loading menu. To add a distributed load:
Select Add Distributed Load from the toolbar or the Loading menu.
In the Distributed Load dialog, enter the load magnitude and orientation (see below for details), and select OK.
As you move the mouse, you will notice a small red cross which follows the cursor, and "snaps" to the nearest point on the nearest boundary line segment.
NOTE: you can add a load on the External Boundary or a Material Boundary. You cannot add loads to water surface or tension crack boundaries.
Enter the start and end points of the load on the desired boundary, graphically with the mouse, or by entering x,y coordinates in the prompt line. After the second point is entered, the load will be added to the model, as you will see by red arrows applied according to the orientation you have selected. The value(s) defining the load magnitude will also be displayed.
A distributed load magnitude represents a FORCE per UNIT AREA (e.g. kN/m2) when considering the out-of-plane dimension of the model.
In Slide the load magnitude is ALWAYS entered as a POSITIVE value. The direction of load application is specified by selecting an appropriate Orientation method (see below) in the Distributed Load dialog.
A triangular (or trapezoidal) distributed load may be created by setting the Type = Triangular in the Distributed Load dialog (Step 2), and entering the load magnitude at each end of the distributed load.
The load orientation in Slide may be specified using one of five options:
Normal to Boundary – loads are applied normal to boundaries
Vertical – loads are applied vertically (default = downwards)
Horizontal – loads are applied horizontally (default = against the direction of failure)
Angle from Horizontal – specify an angle from the horizontal. Note that a POSITIVE angle is measured counter-clockwise from the positive X-axis direction.
Angle to Boundary – specify an angle relative to the boundary on which the load is added.
NOTE: after adding a load, the orientation may sometimes be opposite from the intended direction (i.e. 180 degrees off). If this occurs, you can use the Modify Load option, to simply "flip" the load orientation by 180 degrees. See the Modify Load topic for information about modifying loads.
Excess Pore Pressure
The Excess Pore Pressure option in the Distributed Load dialog, will only be available if the "Calculate Excess Pore Pressure (B-bar method)" checkbox is selected in the Groundwater tab of the Project Settings dialog.
If you select the "Load creates excess pore pressure" checkbox, then the load will generate excess pore pressure, for all materials situated beneath the load, with a B-bar > 0. Only the vertical component of loads contribute to the excess pore pressure. For more information see the Excess Pore Pressure topic.