Rock Bolts
A rock screw is a long anchor bolt, for fixing rock excavations, that can be used for tunneling or rock cutting. As it transfers loads from the outer, non-strong rock layer to the inner (stronger) layer of the rock mass, rock nails were first used in mining in the 1890s.
Rock nails are “round bar” iron skewers with various lengths ranging from 6 m to 12 m with a diameter of 32 mm. They are drilled horizontally with pneumatic drilling equipment, with an inclination of 15 degrees and a diameter of 64 mm.
When inserting these toothed skewers, the cement is injected with the grout material by means of a cement pump through a plastic tube into the perforation depths. This cement material works to fill the cracks and gaps inside the rock and leads to linking these rocks together. These nails are attached using nuts mounted on special galvanized iron pieces.