Slip Surface Type

The Surface Type option in the Slip Surface Options dialog allows you to choose the following options.

NOTE: the choice of Surface Type affects the available Search Methods.

Surface Type

If the Surface Generation Method = Search Methods, then you will be able to choose the shape of the slip surfaces generated by the primary Search Method. The Surface Type options are:

• Sphere
• Ellipsoid
• Multi-Planar
• Wedge

This determines the shape of all surfaces generated by the primary search method (e.g. Cuckoo Search, Particle Swarm).

Search Methods

It is important to note that the selected Surface Type affects the available choice of Search Methods.

• If Surface Type = Sphere, then the available Search Methods are Grid Search, Cuckoo Search, Particle Swarm, Auto Refine (i.e. all search methods are applicable for a spherical surface type).
• If Surface Type = Ellipsoid, then the available Search Methods are Cuckoo Search, Particle Swarm
• If Surface Type = Multi-Planar, then the available Search Methods are Cuckoo Search, Particle Swarm (note: Surface Altering Optimization is NOT available when Surface Type = Multi-Planar)
• If Surface Type = Wedge, then the available Search Methods are Grid Search, Cuckoo Search, Particle Swarm, and Auto Refine
  • Note: the new Wedge analysis uses Swedge type surfaces and gives the option of two planes or two planes plus a basal joint.

External Geometry Composite Surfaces

The External Geometry Composite Surfaces option is intended for modeling a strong bedrock layer at the bottom of a model. It allows the slip surface search routines to form "composite" surfaces (e.g. spherical / planar) which conform to the lower edge of the External boundary volume.

If this checkbox is selected, then slip surfaces (e.g. spheres or ellipsoids) which intersect the bottom of the External boundary, will automatically be intersected with the External boundary, and conform to the shape of the External boundary along the bottom edge. An example is shown below.

Composite spherical / planar slip surface formed by intersection with lower edge of External boundary

NOTE: the material strength used for the "planar" portion of a composite slip surface, will be the strength of the material(s) at the bottom of the External volume.