How simple reinforcement is used to prevent collapse of rock tunnels.Tunnels play an important role in our constructed environment as passageways for mines, conveyance for utilities, and routes for transportation.
source/image(PrtSc): Practical Engineering
Rock bolts are a type of reinforcement for stabilizing rock excavations, usually made from steel bars or bolts. This simple construction method dramatically reduces the cost of making tunnels through rock safe from collapse. Watch the video from Practical Engineering for more info:
A Rock bolt transfers 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 unraveling (piece by piece).
Unlike common anchor bolts, rock bolts can become ‘seized’ throughout their length by small shears in the rock mass, so they are not fully dependent on their pull-out strength.