Rock reinforcements are additional supports that are provided to the rock structures to improve its stability and enhance load-carrying capacity. Let's look at some of the innovations in rock reinforcement below.
FREMONT, CA: The mining industry is ever-evolving, and rock mechanics are turning to innovative methods to increase the safety, productivity, and sustainability of their mines with rock reinforcement. Several ways have developed to strengthen rock stability and maintain strata load-bearing capacity of underground excavations. Rock reinforcement refers to the internal strengthening of rock using bolts and injections of resin or cementitious grout to regain competence, which is essential in squeezing and burst-prone strata conditions. External reinforcement, such as shotcrete and mesh, is known as rock support.
Self-drilling hollow rock bolts
Self-drilling bolts are used in fractured ground or unstable levels because it is not possible to drill a hole due to the risk of collapse. A self-drilling bolt is then drilled into the rock and is left there, and as it is hollow, grout can be pumped tight through it.
Normet's self-drilling dynamic bolts (SDDB) are half threaded, and they can be extended with a coupling, meaning they can be used in place of long cable bolts that are difficult to install. Normet bolts also offer high shear resistance. When excavating underground tunnels, strata needs to tighten together to stop it moving or sliding
Active and passive rock augmentation
Active reinforcement uses rock bolts and anchors. Bolts are then inserted into a drilled hole and pulled, pre-loaded so that they accumulate energy. The hole is grouted, and the pre-tension is released. This method energizes the bolt, which will work against external forces right from the starting.
Passive reinforcement is a process where a hole is drilled and filled with grout before the steel or glass fiber bolt or cable is inserted, reinforcing the rock like a ligament. The bolt is fully-grouted, and forces are not being actively applied to the bolt while using this method.