Bolt Shear Strength

The Shear Capacity of a bolt can be considered in the analysis for any of the bolt types in RocSlope2 except the Simple Bolt Force model.

To include bolt Shear Capacity in your analysis:

1. Select the Use Shear Capacity check box for a Bolt Property in the Bolt Properties dialog.
2. Enter a value for Shear Capacity. The Shear Capacity is simply entered as a force.

The Shear Capacity of a bolt refers to the shear capacity perpendicular to the axis of the bolt (i.e. what shear force would be required to shear through the cross-section of the bolt), as shown in the figure below.

Shear force F required for bolt to fail

Bolt Shear Capacity Implementation

If Bolt Shear Capacity is considered, it is implemented in the analysis as described in the Bolt Support Force topic.

• The shear force is applied only if a bolt intersects a shearing (sliding) plane of a wedge. This corresponds to bolt failure modes d, e or f (as shown in figure of possible bolt deformation modes [Windsor, 1996]).
• Shear force is NOT applied if a bolt intersects a dilating plane (failure modes a, b, or c).
• If shear force is applied, the direction of the applied shear force is always exactly opposite to the sliding direction of the wedge.

Bolt Efficiency and Shear Capacity

Note that Bolt Orientation Efficiency is NOT used in conjunction with the Bolt Shear Capacity option. If you have selected the Use Bolt Shear Capacity option and the bolt failure mode is D, E or F so that the Bolt Shear Capacity is applied, the Bolt Orientation Efficiency DOES NOT multiply the shear capacity. The Bolt Orientation Efficiency is used only as a factor for the tensile Bolt Capacity determined from the Bolt Force Diagram. It has no effect on the Bolt Shear Capacity.