Focus Search

By default, a Grid Search in Slide uses the currently defined Slope Limits, in conjunction with the Radius Increment, to generate the circle radii associated with each point in a slip center grid. This is described in detail in the Grid Search topic.

The Focus Search options allow the user to focus the Grid Search to specific regions within the slope, using one of the following four options:

Focus Window

Focus Line

Focus Point

Focus Tangent

Comparison of Focus Methods

The following figures illustrate the effect of different focus methods on the slip surfaces generated by a Grid Search. In each figure, ALL slip circles generated by the Grid Search are shown, colour coded according to safety factor.

Default Grid Search, based on Slope Limits. No focus object is used.

image\focus0x.gif

Example of Grid Search using Focus Window

 

image\focus1xxx.gif

Example of Grid Search using Focus Line

image\focus2xxx.gif

Example of Grid Search using Focus Point

image\focus3xxx.gif

 

It is important to note that if you define a Focus Object (window, line, point or tangent), then the Slope Limits are NOT used to generate the circle radii, but are still used as a filter, to ensure that only surfaces which intersect the slope within the Slope Limits, will be analyzed.

Only ONE Focus Object may be defined for a given analysis. Multiple Focus Objects are not allowed for a circular slip surface search.

NOTE: a Focus Object can also be defined for the Slope Search method for circular slip surfaces. Again, this is optional, and is not required by the search. See the Slope Search topic for details.