# Slope Geometry

The **Slope Geometry** parameters for your **RocTopple** model are entered in the **Geometry** tab of the **Input Data** dialog. To open the tab:

- Select
**Input Data**on the toolbar or the**Analysis**menu or press F3.

You can enter the following data in the tab:

- Slope Angle
- Slope Height
- Upper Slope Angle
- Bench Analysis Width
- Toppling Joints Spacing
- Toppling Joints Dip
- Overall Base Inclination Angle
- Rock Unit Weight

## Slope Angle and Height

The **Slope Angle** is the dip angle of the front face of the slope. The **Slope Height** is the vertical height of the slope measured from the toe to the crest.

## Upper Slope Angle

The **Upper Slope Angle** is the dip angle of the upper face of the slope . If horizontal, enter zero. A negative value can also be entered if the upper slope dips backwards in the opposite direction from the front slope face.

## Bench Analysis Width

By default **RocTopple**, automatically computes a maximum **Bench Width** based on the slope geometry (**Slope Height**, **Slope Angle**, **Upper Slope Angle**, **Overall Base Inclination Angle**). This determines the maximum possible bench width (i.e., horizontal extent of the upper slope).

If you want to define a **Bench Width** that is smaller than the default, select the **Bench Analysis** check box and enter a value of **Bench Width**. In this case, the number of toppling blocks is automatically truncated to approximate the required **Bench Width**. The **Bench Width** number is not exact, it is simply used to reduce the number of toppling blocks on the upper slope. The actual **Bench Width** greater than or equal to (not less than) the number you enter due to the discrete number of blocks. The figure below shows a model with a user-defined **Bench Width**.

**NOTE:** The **Bench Width** is defined as the *horizontal* distance from the crest of the slope, even if the Upper Slope Angle is not horizontal.

## Toppling Joint Spacing and Dip

The **Toppling Joint Dip** is the dip angle into the slope of the primary toppling discontinuities. The **Toppling Joint Spacing** is the perpendicular spacing between toppling discontinuities. In **RocTopple** version 1.0, it is assumed that the spacing is equal for all toppling blocks.

## Overall Base Inclination

The **Overall Base Inclination** is the angle of a line from the toe of the slope to the exit point on the upper slope, which defines the overall failure direction or base line of the toppling mass.

In general, the **Overall Base Inclination** is NOT equal to the inclination of the base of the toppling blocks. Because it is assumed that the base of each toppling block is perpendicular to the toppling joint angle, the **Overall Base Inclination** is always greater than (or equal to) the block base angle.

The **Overall Base Inclination** is equal to the block base angle only when the toppling joint dip is perpendicular to the overall base inclination (i.e. if toppling joint dip + overall base inclination = 90 degrees).

## Rock Unit Weight

The **Rock Unit Weight** is entered according to the unit system specified in the **Project Settings** dialog.