Rockbolts Essay

Rockbolts as a ground control technology are just one in the very long list of ground control technologies that exist in mining and civil applications. The simplicity and reasonable cost associated with rockbolts are the primary driving forces for the research causing their wide variations for numerous public and private uses. The ease of calculation and implementation also makes rockbolts a go to option for engineers who would rather spend more time calculating other variables during a job which requires moderate to secure rock, for either permanent or less than permanent structures. With the continuation of expansion, which requires bigger highway cuts, tunnels, and mines, has given way to the need for more cost effective ground control technologies. …show more content…
The basic parts of a rockbolt are; the bolt, the keyhole plate, a nut, and a setting tool (Hartman & Mutmansky, 2002). The bolt must be tensioned with the correct force and set with the correct angle as calculated for the scenario (de la Vergne, 2008). The three main types of rockbolts are; mechanical bolts, resin bolts, and friction bolts (Hustrulid & Bullock). The mechanical bolts are mechanical point anchors which, when set in the predrilled hole, are then tensioned to secure an anchoring device which will pull against the keyhole plate and the anchor point to secure the surface to a more competent layer. The mechanical bolts have more parts to go wrong, as well as a higher cost. The mechanical anchors have though shown to be a very reliable way to pull the unstable layer back to the competent layer. The forces are not being applied directly to the sides of the hole in its entirety, but rather a tensile force between the plate and the anchor device point. Multiple devices for anchoring have been developed over the years in an attempt to lower the costs and increase the amount of force the bolt is able to withstand, both tensile and shear. Grout can even be forced into the remaining gaps around the bolt after the anchoring device has been applied (Villaescusa, Windsor, & Thompson, 1999). Some of the types of resin bolts include; the paddle bolt, posimix, solid deformed, wiggle bolt, and chemical anchor. The resin bolt differs primarily because it utilizes chemical compounds to secure the two rock layers. The chemical coumpounds are a grout which when applied causes the space between the bolt and the hole to be filled and become solid, which in turn secures the surface layer of rock. The resin bolts have seen a recent boom in research due to the seemingly cost effective nature. With the correct setting and grout resin they prove to be a reliable