Yielding reinforcement elements in rock bolting technology

Rock reinforcement is a key issue in underground design and construction. However, for certain applications where both adequately high supporting forces and the ability to overcome large displacements are required, it is often difficult to find a
proper reinforcement unit. This paper describes historical approaches and examples for yielding support elements and recent developments focusing on a newly-developed friction stabilizer reinforcement unit. This reinforcement unit has been an object of several investigation and field testing projects. These testing approaches have shown that this rock bolt with the trade name “AT -Power Set” is well suited to overcome large displacements while maintaining its load-bearing capacity. In particular, the focus will be set on results of tests conducted at the Edgar Experimental Mine of the Colorado School of Mines in the years 2003-2004.