A rock bolt is a long anchor bolt used for stabilising rock faces. Rock bolts transfer the load from the unstable exterior to the confined (and much stronger) interior of the rock mass. Rock bolts work by 'knitting' the rock mass together sufficiently before it can move enough to loosen and fail by unravelling (piece by piece). Rock bolts are commonly used in tunnels or rock cuts.
Rock bolts can either be anchored into the rock by mechanical or epoxy means. Rock bolts are made from steel or Fibre Reinforced Polymers (FRP). The most common FRP is fibreglass (GFRP), but other systems are available.