Factors that Affect Durability of Rock Bolts

To ensure the safety of mining operations, there are many techniques and supporting elements that have been used to strengthen long term stability of rock tunnels. In mining, these rock tunnels are excavated and this leads to stresses on the rock mass. Rock bolts are used to control deformations of the rock and to maintain stability.

There are many systems in place to ensure that the design and performance of rock bolts are kept at a high level. There are many companies such as Mine Civil IT Ground Equipment that provide ground support testing services to ensure that the mine is safe to work in. However, once a rock bolt has been used, you should have an idea of how to strengthen its durability. There are certain factors that can influence its durability over the long term. One such factor is the strength of the rock. If the rock bolts are inserted into the rock properly, you can be sure that they have a long life. But when the strength of the rock mass is low, the life of the rock bolts can be reduced. But there are countermeasures that can be taken. When the rock has high strength, there is less cross strain on the rock bolts. There has to be constant surveillance to ensure the performance of the rock bolts. And when the level of deformation of the rock increases, you need to find more efficient support systems.

You also need to consider the creep behaviour of rocks. There are certain types of rock that can experience creep deformation at very high depths. Creep is used to refer to high deformations that are consistent. It is difficult to prevent this as there are high stresses in site and it is impossible to control geological conditions that occur at great depth. However, you need to make sure that the rock bolts used are able to cope with these deformations. This requires high strength and ductility for the rock bolts. If the capacity of the rock bolts used is not sufficient, they can fail. When the deformations in the rock increase suddenly, the rock bolts can fail.  Groundwater can trigger failures when it comes to excavating deep rock, you need to make sure that the rock bolts properly fill the boreholes so that water cannot infiltrate the openings. If there is water, it will reduce the resistance of the rock to creep deformations.

It is also important to consider the materials used for grouting and bolting. These are subjected to high stress so you need to select the proper bolting material. Steel is generally used for this. Depending on the geological condition of the rocks, the engineers will decide to use either a ribbed or smooth bolt. Ribbed bolts tend to have better adhesion when it comes to rocks at great depths. Ribbed bars tend to have more resistance to pull loads than smooth bars. When there are large deformations, you need to grout the rock bolts to increase their effectiveness. But you need to choose the right type of grout for this.


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