You are reading the online version of the LimitState:GEO manual, which is also available as a pdf.

Scenario Manager and Partial Factors

Introduction

The Scenario Manager (depicted below) is a powerful facility that permits several scenarios to be solved as a single set. This is a common requirement in geotechnical engineering, where for example undrained and drained cases may need to be checked, or where several design combinations of partial factors may need to be checked for the same geometry as is required by codes such as Eurocode 7. It is also used to specify partial factors for solution of single problems.

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Specification of Partial Factors for a Single Scenario

Ensure that the Single scenario radio button is selected. One scenario Scenario 1 is available. The User Partial Factor set is listed by default. Its default settings are all unity. To change any factor, double click on the entry (as shown below), and change its value.

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These Partial Factors will then be applied to the current problem. Loads may be individually defined as Permanent, Variable or Accidental and favourable / unfavourable / neutral (see Setting applied loads). Material self weight is defined as Permanent but may be specified as favourable / unfavourable / neutral (see Setting applied loads). Note that no partial factors are applied to the basic soil nail material type.

In addition to specifying individual Partial Factors, the user may select from a pre-defined set of partial factors by using the drop down box (as shown below) or create a new list.

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Specification of Long and Short Term Analysis Mode

Under the options heading (as shown above). It is possible to set the scenario to solve as either a long term (typically drained) or short term (typically undrained) problem as described in Analysis Modes. This setting may also be set globally via the project properties using the Property Editor as described in Analysis Settings.

Specifiying Multiple Scenarios

Ensure that the Multiple scenario radio button is selected. On first use, two scenarios Scenario 1 and Scenario 2 are listed. The User Partial Factor set is listed by default for Scenario 1 and None is listed for Scenario 2. This may be changed to an actual Partial Factor set using the drop down box. If this is done, a new empty scenario (Scenario 3) is displayed. Further scenarios may be defined in this way.

To remove any scenario from the set of scenarios, select Delete from the drop down box. An error message will be displayed if this action would reduce the number of scenarios to zero.

Exporting and Importing Scenarios

All Partial factor sets listed in the drop down box may be exported to a .csv file by selecting {Export...}.

To import previously exported sets of Partial Factors, select {Import...}. Partial Factor sets with the same name are not overwritten.

All Partial Factors are saved with the main file.

Solving with Multiple Scenarios

When multiple scenarios are defined, clicking Solve solves each scenario in turn and displays the failure mechanism in a separate tab in the Viewer pane (see Multiple scenarios). Numeric solutions are also displayed in the Output pane and the critical case is highlighted. The other solutions may be viewed by clicking on the respective tabs.

Overall solution time is typically faster than if each scenario were solved individually since solution mechanisms are typically fairly similar for common Partial Factor sets.

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