Speed improvementsTo our surprise we found that some customers were creating multi-scenario Slide files with dozens or in some cases over one hundred scenarios. This led to speed issues in editing and file management. In Slide 2018 the multi-scenario file manager has been optimized to handle large numbers of scenarios with no slow down in performance.

Surface Altering OptimizationFor the critical slip surface search, a new optimization method has been added – Surface Altering Optimization. This option has been shown to be much faster (10 to 15 times) than the Monte Carlo algorithm for most cases, and is the new default search optimization method for non-circular slip surfaces.

Slide 2018: A preview

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A new version of Slide is due to be released in early 2018, and will be known as Slide 2018 (or, sequentially, Slide version 8). This article will give a sneak preview of the new features we are working on.

Improved Scenario ManagerThe multi-scenario modeling feature introduced in Slide version 7 has proved to be one of the most popular and extensively used options in the program. Based on customer feedback, some important improvements to this feature have been made in Slide 2018.

New Master ScenarioA new master scenario file has been introduced, which allows you to more easily propagate changes to all scenarios in a group. Simply edit the master scenario file and all changes will automatically propagate to all scenarios in the group.

Link scenariosA new “link” feature has replaced the previous “lock” feature. Linking allows you to easily propagate changes to user-selected scenarios, instead of all scenarios.

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Spatial variability of material propertiesA new probabilistic analysis option – spatial variability – has been added to the already extensive probabilistic analysis capabilities in Slide.

Most real geotechnical materials have properties which vary with location within the material, to some extent. This type of variability is not accounted for in a standard

probabilistic analysis, which assumes a single value of each material parameter over an entire soil region, for each statistical sampling.

With spatial variability analysis, a correlation length is defined for each material which is used to generate a random field for that material. For each sampling, a new random field is generated. Considering spatial variability of soil properties has been shown to improve the mean factor of safety and probability of failure calculated for a probabilistic analysis. We are pleased to offer this new analysis tool for probabilistic slope stability.

The correlation length determines the scale of variation of properties within a material (smaller correlation length corresponds to higher variability of material in the slope profile), as illustrated below for a random field of cohesion, using two different correlation lengths (20 meters and

Cohesion contours, correlation length = 20

Cohesion contours, correlation length = 1

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1 meter). The results below represent one statistical sampling (i.e. one instance of a random field). A full analysis will generate a new random field per material with each sampling.

Anisotropic SurfacesSlide has several different options for modeling anisotropic material strength. In Slide 2018 a new option has been added which makes it simple to model an anisotropic material with a variable orientation, such as a folded bedding layer.

With the new Anisotropic Surface option, the user simply defines a polyline which follows the orientation of the anisotropy for a given material. The compute engine then uses this polyline to determine the local orientation of the bedding relative to the slip surface at any location, to apply the correct material strength, using the anisotropic strength envelope.

Anisotropic surface (pink dotted line) defines bedding orientation for green material layer

Weak LayersIn previous versions of Slide, a weak layer had to be modeled as a material zone of finite thickness bounded by two material boundaries. In Slide 2018, a new boundary type has been added which allows you to define a weak layer using only a single polyline. This can be used to model

joints or other types of interfaces along which sliding may occur. This option is intended to be used for thin weak layers of negligible thickness (e.g. a geosynthetic liner). The search algorithm will attempt to follow the weak layer while searching for the global minimum slip surface.

Weak layer boundary (orange dotted line) Cohesion along slip surface equals zero along weak layer

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Generalized Hoek-BrownAn improvement has been made in the input for the Generalized Hoek-Brown material model. Users can now directly input the parameters GSI, mi and D, in the Material Properties dialog, since these are usually the known parameters. Furthermore, an additional new option allows you to define the parameters GSI, mi and D as variable with depth, by selecting the checkbox shown below.

Newmark Seismic OptionAn improvement to the Newmark seismic analysis option allows you to run all methods simultaneously (rigid, coupled, decoupled), rather than having to run the analysis separately for each method. Results for all methods are then available for viewing.

Material Property ViewerA new option allows the contouring of material properties and other data directly on the model. Originally developed for contouring spatially variable data (as shown in the above figures), this option will also extend to other data types (e.g. cohesion which varies by depth, friction angle, unit weight, water pressure, etc.).

Other new features include:• Easier to add/delete materials in material properties

dialog; user can now change the order of materials in the list.

• Infinite strength material – new option to allow sliding along boundary of an infinite strength material (similar to the external boundary composite surface option)

• New support model options for soil nails and piles• Slope wizard for multi-scenario file creation

SummarySlide 2018 is still under development, and additional features are planned. Stay tuned for the beta release in late January 2018. Register to be a beta tester by clicking here.

The direct input of mb, s and a option is still available for users who have this data.