Rock reinforcements provide extra supports to the rock structures so that the stability and load bearing strength of the rock is enhanced. Rock reinforcements are arranged in the type of rock bolts, rock anchors or rock dowels.
Types of Rock Reinforcement: The support given with rock reinforcements ranges from active type or passive type.
For active support, a predefined load is enforced on the rock surface while being set up. Under passive type, a load is formed when the rock mass deforms or dislocates.
The following types of rock reinforcements are commonly found :
1. Rock Bolts: This type of rock reinforcement is frequently used at the end of the borehole. These belong to steel rods which are grouted into the rock. These comprise of a grout anchor or friction on the rock. As soon as the anchorage is obtained, it is tensioned and a compressive force is produced into the adjacent ground.
The axial force produced operates on the rock-mass discontinuities which enhance the shear strength of the mass. This shear strength is produced through the pre-tensioning of the bolt.
2. Rock Dowels: This is a passive type of rock reinforcement for which a ground displacement is required for its activation. When the discontinuities in the rock mass are susceptible to displacement, the dowel undergoes both shear and tensile stresses.
3. Rock Anchors: This method of rock reinforcement employs compressive or uplift force to make any structure or rock mass stable which exist in the ground or underground. These belong to high tensile strength bars. These are pre-tensioned by fixing at the end of the borehole.
Rock anchors belong to either un-tensioned anchors or tensioned anchors. To combat failure of the rock mass caused by shear, rock anchors are used.
Usages of Rock Reinforcement:
The purpose of rock reinforcement is to give safety and temporary supports for several underground construction works. Given below, the different uses of rock reinforcement :-
1. Rock reinforcement is mainly applied to pre-load the foundation.
2. It is applied for the purpose of producing a reaction throughout the pile load test.
3. Rock reinforcements (Rock Anchors) can fasten the suspension cables and guy wires for the bridges.
4. It facilitates to bind the wire cables with the foundation under the sea.
5. Rock reinforcement combat uplift occurred in transmission towers, foundation and hydraulic structures caused by lateral forces.
6. Rock anchors are provided to support sheet piles.
2. It is applied for the purpose of producing a reaction throughout the pile load test.
3. Rock reinforcements (Rock Anchors) can fasten the suspension cables and guy wires for the bridges.
4. It facilitates to bind the wire cables with the foundation under the sea.
5. Rock reinforcement combat uplift occurred in transmission towers, foundation and hydraulic structures caused by lateral forces.
6. Rock anchors are provided to support sheet piles.
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