# Slide3 Overview

This page provides an overview and summary of the main steps required to create a *Slide3* model and analyze the results.

*Slide3* is designed to be as straightforward as possible to use, for a fully 3D numerical analysis program. The most complex aspect of modeling is Geometry creation and editing. Most other features are quick to learn and interpret, once you have mastered the Geometry aspect of the program.

The general workflow is as follows:

- Project Settings (Units, Analysis Methods, etc.)
- Geometry (Add Geometry, Set External, etc.)
- Groundwater
- Define/Assign Materials
- Support
- Loads
- Surface type/Search Method (Slope Limits)
- Compute
- Results

## Project Settings

**Select:** Analysis > Project Settings

The Project Settings dialog is the starting point for all Slide3 models, and allows you to configure the main settings for your analysis.

### Units

*Slide3* offers several choices of **metric or imperial Units**. The units should always be selected before any other modeling is carried out.

### Analysis Methods

The Analysis Methods can be selected at any time. Available methods are Bishop, Janbu, Spencer and GLE. At least one method must always be selected.

### Groundwater

For pore pressure modeling, Groundwater methods include:

- Water Surfaces (e.g. water table, piezo surface)
- Ru coefficients
- Water Grids (total head, pressure head, pore pressure)

Advanced groundwater options include:

- Excess Pore Pressure
- Rapid Drawdown Methods

### Boreholes

If your Geometry is defined from borehole data, the **Boreholes** tab in Project Settings allows you to choose the interpolation method for surface reconstruction.

### Seismic

The **Seismic** tab in Project Settings allows you to select advanced options including:

- Compute Ky for all failure surfaces
- Staged Pseudostatic strength

### Results

The **Results** tab in Project Settings allows you to configure some settings related to data output.

## Geometry

Geometry is by far the most complicated aspect of creating a *Slide3* model. *Slide3* models can range from very simple 2D extrusions, to very complex 3D geometry requiring many steps to create.

Geometry can be created entirely within *Slide3* and/or imported from a variety of file formats. Boundary surfaces can be interpolated from borehole data using the Borehole Manager.

A wide array of geometry modeling tools allows you to create any complexity of 3D slope model with any number of material regions. Since the steps required to create *Slide3* model geometry will vary greatly depending on the model and its complexity, and there are multiple ways to achieve tasks, it is impossible to provide a simple checklist of required steps for geometry creation that apply to all models.

### Geometry Modeling

A summary of the main geometry creation and editing tools is given below. We can add geometry using the following tools:

- Import/Export various file formats
- Reconstruct Surface from Table values entered by the user
- Adding External Geometry
- Adding Polylines
- Adding 3D Primitive Geometry, such as boxes, cylinders or cones
- Create Surfaces from Selected geometry
- Extract Bounding Curve from surfaces
- Planar Section Tool to extract polylines from geometry using a cutting plane

We can also edit geometry shape by applying the following tools:

- Extrude/Sweep/Loft operations to add depth dimensions
- Transform operations such as translate and rotate
- 3D Boolean operations to combine, remove or divide geometry

For details see the *Slide3* help documentation and tutorials.

### External Volume

One mandatory step which is common to ALL *Slide3* models, is the necessity to define an External volume from your model geometry. This defines the total extent of your slope. There are different options for defining the External volume:

- Set as External
- Create External Box
- Create External from Surface
- Add to External

## Materials

**Select:** Materials > Define Materials

*Slide3* offers 15 different strength modeling options for soil and rock, including:

- Mohr-Coulomb
- Undrained
- Infinite Strength
- Anisotropic Strength
- Shear/Normal Function
- C/Phi Function
- Generalized Hoek-Brown
- Vertical Stress Ratio
- Barton-Bandis
- Power Curve
- Hyperbolic
- Discrete Function
- Drained-Undrained
- Generalized Anisotropic
- SHANSEP

After defining material properties, you must assign them to the different material zones in your model, using the Assign dialog or the sidebar panel.

## Groundwater

Groundwater Methods in Slide3 include:

- Water Surfaces (water table or piezo surfaces)
- Ru Coefficients
- Water Grids

If the Groundwater Method = Water Surfaces, then you can define a Water Table or Piezometric Surfaces to define pore pressure.

**Select:** Groundwater > Add Water Surface

Water Surfaces can be defined by assigning an existing geometric surface, or by entering XYZ coordinates and interpolating a surface. If a Water Table elevation is above the ground surface, ponded water is automatically accounted for in the stability calculation.

**Select:** Groundwater > Add Water Grid

If the Groundwater Method = Water Grids, then you can enter XYZ coordinates defining a grid of pore pressure, pressure head or total head. Interpolation is used to determine pore pressure at any location. Pore pressure grids can be imported into *Slide3* from an RS3 finite element analysis or another source.

The Groundwater Method can be assigned independently for individual materials, giving a great deal of flexibility in defining pore pressure conditions.

## Support

Support types which can be modeled in *Slide3* include:

- End Anchored
- Grouted Tieback
- Soil Nail
- Micro Pile
- Geotextile
- User Defined

**Select:** Support > Define Support

The Support Properties dialog looks as follows:

**Select:** Support > Add Support or Add Geotextile to add support to the model

Support can be applied at any orientation in 3‐dimension, either as individual bolts or patterns. Orientation options include normal, trend/plunge or vector.

## Loads

Loading options in *Slide3* include:

- Point Loads
- Distributed Loads
- Seismic Loads

Loads can be applied at any 3D orientation or location.

Seismic Load dialog

## Slip Surfaces

The Slip Surface Options dialog gives a variety of slip surface shapes and search options.

The 3D slip surface shapes which can be generated are:

- Spherical
- Ellipsoidal
- Spline Surface

When using Spherical or Ellipsoid surfaces, the initial search is constrained to a spherical or ellipsoid shape. An additional **Surface Altering Optimization** can be applied to search for a Spline surface with a lower safety factor.

### Search Methods

Search methods include advanced methods optimized for speed and efficiency (Cuckoo and Particle Swarm), as well as more traditional methods (e.g. Grid Search and Auto Refine):

- Cuckoo Search
- Particle Swarm
- Grid Search
- Auto Refine

Slip surfaces can conform to the shape of bedrock using an Infinite Strength material region (see following figure). The 3D failure direction is automatically determined during the analysis; it is not necessary for the user to specify a failure direction.

2D view of slip surface sliding on bedrock (infinite strength material)

The default search options are highly automated. For a typical initial analysis, the default settings are:

- Surface Type = Ellipse
- Search Method = Cuckoo Search
- Surface Altering Optimization = ON

Using the default settings, the user can run an analysis and obtain results without changing the settings. Of course, the user should become familiar with the available search methods, and always try different options to ensure that critical slip surface(s) are located.

### Search limits

To narrow down the search areas of the model, the **Slope Limits option** can be used to define inclusion or exclusion zones to focus the search on particular regions of the slope.

The default search limits include the entire External Volume. Slope limits do not have to be defined by the user unless you wish to customize the search area on the slope.

One advantage of the 3D slope stability analysis in *Slide3*, is that the user does not have to specify a sliding direction. The sliding direction is an outcome of the limit equilibrium analysis, and is automatically computed for each slip surface.

See the *Slide3* Theory Overview for more information.

## Compute

**Select:** Analysis > Compute

The Compute dialog will indicate the progress of the analysis, for each selected analysis method and search method.

If the Compute option is disabled, then the model is incomplete and cannot be computed. For example, if the External volume is undefined.

## Results

After Compute has completed, to view analysis results select the Results tab.

Data interpretation options include:

- View 3D global minimum slip surface
- View contours of analysis data on slip surface (e.g. stress, strength, pore pressure)
- View all slip surfaces
- View safety maps on the surface of the model or on cutting planes through your model
- View support forces
- View column forces

The Data on (XY/YZ/XZ) Plane options allow you to view safety factor, pore pressure and other analysis data on cutting planes through the model. You can sweep the cutting plane along an axis to show the data at different locations. The results displayed represent data from all slip surfaces generated throughout the model volume.

The **Column Viewer** option allows you to view analysis data for individual columns, as selected in the XY, YZ or XZ planes.