Introduction to new methods of static and dynamic pull testing of rock bolts and cable bolts

ABSTRACT: Despite the decades where application of rock bolts and tendons have been the main supporting system for ground in both hard and soft rock formations in mines and tunnels, there remains significant uncertainty about the behaviour and performance of these easy-to-use technologies. The importance of effective support is paramount with regard to ground seismicity and dynamic loading cause by outburst, rock burst and rock blasting activities. The evaluation and assessment of the axial loading and shear behaviour of rock bolts enables the design of a credible methodology for effective and sound ground reinforcement. This paper deals mainly with the development of a pull testing rig that is used for the testing of cable bolts and tendons under both static and dynamic conditions. The dynamic test was carried out by the drop hammer impact test. It was found that a 30 % greater pulling force is needed for the pull testing of cables statically in comparison with the dynamic impact test, this being in agreement with past numerical studies.