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Skema Rock Bolts

Skema Friction Rock Stabilizers design allows bolts to tighten should lateral rock displacement occur, enhancing yielding capabilities.

Manufacturing - A hollow tube slit lengthwise.  Tapered on one end and a welded ring at the other to hold the plate.  A square plate is used to stabilize the shaft and hold it in place, as well as retaining wire screen against the rock face.

Installation - The tapered end starts the tube, into a smaller hole drilled in rock and the long slit allows compression of the tube.. The compressed tube exerts radial forces which increase as rock displacement occurs generating active resistance.

Components - Consist of the tube, matching domed bearing plate, and driver tool fitting the rockdrill used to drill the holes.  Drivers are available to fit jacklegs, stopers and drifters for each bolt diameter.  PHQ make a hydraulic pull tester that measures the holding strength of bolts after installation, and over time. Pull collars are available by tube diameter.

Choices -  Stabilizers are available in 33mm, 39mm and 46mm diameters, and in lengths to suit requirements. Bolts can be supplied in black or hot dip galvanized steel to satisfy environmental corrosive conditions.

Ground Shifts Grip Tighter - Pull tests prove the superior holding power of the Friction Rock Stabilizer system. After installation when ground shifts (often caused by blasting in the area) loosen conventional rock bolts, the Friction Rock Stabilizer tube grips more tightly. Often, within weeks or months, when the average conventional bolts becomes ineffective and require re-torquing, typical stabilizer bolts retain full load-bearing characteristics. Skema Friction Stabilizer tubes never need tightening. The tubular structure and high strength of the Friction Rock Stabilizer allows it to conform to rock displacements.

Types of Rock Bolts



In the hole, the outer wall of the tube exerts forces against the rock over the  full contact length of the tube, as well as providing support to the plate.


Full Length Support - The Friction Rock tube applies frictional properties over its full contact length; not just at the end as compared to a standard shell type point-anchor bolt.. The tube and bearing plate exert forces to hold the rock immediately upon installation.

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Last modified: March 14, 2017