Perimeter Support: Add Bolt Pattern

A regular pattern of bolts can be applied to the perimeter of the excavation, with the Add Bolt Pattern (Perimeter Support) option. The pattern location, bolt length, spacing, orientation, z-offset, can all be defined by the user.

Note: on the perimeter, you are not limited to a single bolt pattern, you can apply multiple patterns with different bolt properties, lengths, spacing, z-offset etc.

To apply a pattern of bolts to the perimeter:

  1. First, make sure you are viewing the Perimeter Support Design view (select the Perimeter Support Design button from the toolbar).

  2. Select the Add Bolt Pattern option from the Sidebar, the Support menu or the right-click menu.

  3. You will see the Add Bolt Pattern (on Perimeter) dialog. In the dialog, enter the following information and select OK.

  1. You will then be prompted to enter the drilling point (if applicable, see below), and the starting and ending points for the pattern.

  2. Drilling Point - if you selected Pattern Orientation = From Drilling Point, you will first be prompted to enter the x-y coordinates of the origin of a radial drilling pattern. You can enter the point graphically with the mouse, or you can type the coordinates in the prompt line. (For other pattern orientations, you will not see this prompt, proceed directly to Step 6).

  3. Start / End Points of Pattern - for all Pattern Orientation types, you must define the starting and ending points of the pattern, on the perimeter of the excavation (i.e. on the Opening Section boundary). This can be done graphically with the mouse, or by entering coordinates in the prompt line.

NOTE: The bolt pattern is always created in a counter-clockwise direction around the perimeter, from the Start point to the End point. Therefore you must define the start and end points accordingly. If you enter the points in the wrong order, you will have to start over. If this occurs, press Escape to exit the option, or if you have already entered an incorrect pattern, select Undo.

  1. NOTES:

Multiple Bolt Patterns

On the perimeter, you are not restricted to only a single bolt pattern. You may define additional bolt patterns as required, by repeating the above steps.

Multiple bolt patterns allow you to define patterns with different bolt properties, lengths, spacings etc. The Out-of-Plane offset option (see above) allows you to offset different patterns by a specified amount, in the direction of the tunnel axis.