Evolution of grouting methods for dynamic supports in broken ground

Rockbursts are seismic events of deep or high stress mines that often lead to damages to the ground support system. Even when the rock at the contour of the excavation is broken, rockbursts can occur behind this soften zone and damage the support system further.  In these broken conditions, the ductility of the ground support system is still critical, but the installation of grouted tendons is rendered tedious or very inefficient by the problems associated with inserting cartridges of resin inside the boreholes. The same practical issues with resin cartridges arise while bolting in squeezing ground conditions or in damaged pillars. This study aims at investigating alternative methods of grouting dynamic rockbolts by methods other than the polyester resin cartridges traditionally used by the mining industry. In particular, the use of injected resin grout for reinforcement is analysed in the field.  The static anchorage capacities of the injected resin is evaluated using D-Bolts and Self-Drilling Bolts (SDB) by the mean of  pull out tests, and compared with the performance of similar bolts anchored with resin cartridges in hard rock conditions, and grouted with cementitious grout. Drop tests evaluation of the resin was postponed due to scheduling difficulties. The study also includes a field evaluation of the installation method, sequence and bolting speed, for typical length tendons. The implications of the installation with injected grout on the resulting capacity and estimated safety performance are discussed.