The anchoring system of a friction bolt, also known as a Split Set, is a rock support method used in underground mining and tunnel construction. This system consists of a high-strength steel bolt with a “U” shaped cross-section and a longitudinal groove.
To install a Split Set bolt, a hole is made in the rock with a diameter slightly smaller than the bolt’s diameter, and the Split Set is inserted into it. As the bolt is pushed into the rock, the “U” shaped cross-section reduces and adjusts to the shape of the borehole. This expansion creates friction between the Split Set and the surrounding rock along its entire length, providing strong resistance to displacement.
The Split Set can also have a flat or curved plate on one end to distribute the rock load over a larger surface area, increasing its support capacity. Once the bolt is inserted in place, concrete masonry, fill or mesh can be placed to complete the support and stability.
The Split Set anchoring system is an effective way to support rock in underground mining and tunnel construction due to its ease of installation and immediate load-bearing capacity.