What Are Self Drilling Rock Anchors?

Self drilling rock anchors are also called anchor bolts, rock bolts, rock bars, and so on. They are those that can change the game rules when it comes to safety in construction and excavation industries. Developed through more than 100 years, rock anchors now can be installed more easily, lower cost, and perform well when bolting fractured rocks and soils to keep people and equipment safe. It is what self drilling rock anchors do.

self drilling rock anchors of Sinorock

What Are Rock Anchors?

Rock anchor is a kind of engineering material that could be used to support the unstable formations, such as slopes, civil construction foundations, tunnels, and mining. Its function is to stabilize, to reinforce, and to support where rock and soil probably collapses or slides. 

At the beginning, the rock anchors are made of timber, brick, or masonry. Usually, it is made of steel bar or fiber reinforced plastic, whose surface is threaded. It will be put in the drilling hole during excavation so as to prevent broken, fractured, and loose rock masses collapses, which will threaten the equipment and workers’ safety.

The History of Rock Anchors

As far as we know, human using rock anchor starts from 1890’s. Decades later, in 1947, Australian engineers tried 4 meters long expanding rock anchor bolt in a complex hydroelectricity and irrigation construction.

Nowadays, rock anchor turns to be self drilling rock anchor, which can be used in a huge range of construction projects. And we will introduce this later.

How Many Types of Rock Anchors Are There?

There are so many types of rock anchors now in the construction field. Let’s see the detail below.

Grout Rock Anchors

It is made of steel or rebar with surface threaded. If we want to use a grout rock anchor, we generally need to drill a hole first, and put it in. And then, we can use cement or resin to fill the space between the hole wall and the grout rock anchor, and the cracks of the rock mass. 

Cable Anchors

The cable anchors are a types of pre-stressed rock bolt which has a free length. The most special feature of cable anchor is light. This allows us to support the constructions with a lighter bolt weight.

Cable Anchors

Hollow Rock Anchors

Apparently, hollow rock anchor has an inner hollow path, through which we can grout the slurry when putting it in the drilling hole. That’s relatively more convenient to install than grout rock anchors since we don’t need a grouting pipe additionally.

Self Drilling Rock Anchors

Self drilling rock anchor is the most convenient method to support unstable conditions at present.

What Are Self Drilling Rock Anchors?

Self drilling rock anchor is an advanced technique to support the constructions. It consists of a one-time use drill bit, which could be selected according to the geological conditions, a hollow bar alike the hollow rock anchor, a coupler to continue the hollow bar if necessary, a plate, including two types, flat and domed, a nut, and a centralizer.

self drilling rock anchor of Sinorock

Currently, the self drilling rock anchors are divided into two types, R thread and T thread. R thread is meet the ISO 10208 and suitable for most drill rig. However, there are no unified standards for T thread rock anchors, so it’s up to every single manufacturer. 

Sinorock achieves product traceability, and the main products have the identification of the batch number of circulation. Through the batch number of circulation, the customers can trace back to the related information such as the product raw material manufacturers, texture and processing and inquire the product information quickly as well as effectively.

Self drilling rock anchor combines drilling, grouting, and anchoring into one process. It is suitable for broken rock, loose soil and geological conditions where are difficult to drill holes. It helps to ensure anchoring effect in complex ground conditions and achieving best construction result.

How Do Self Drilling Rock Anchors Work?

Firstly, we need choose the rock anchors according to the required specifications, such as ultimate load, yield load, outer and inner diameter, length and so on.

Secondly, we drill the self drilling rock anchor in with a drill rig, simultaneously we use a grouting machine to grout. If necessary, the slurry could be grouted under a high pressure so that the slurry could fill in the inner cracks of rocks. Thus, the broken and loose rocks will jointed together. If necessary, the bearing plate can be put on and the rock anchor will be tensioned.

Where Can Self Drilling Rock Anchors Be Used?

In most projects, we need to support the foundations, roofs, and slopes during the construction. And the best solution to this is self drilling rock anchor. Therefore, the self drilling rock anchor is widely applied to these field. 

In tunnels and underground projects, self drilling rock anchor is mainly used for initial support or pre-support. According to the types of support in the tunnel, it can be divided into fore piling, radial support, tunnel-face support, locking the foot support and reinforcement of the tunnel portal.

Self drilling rock anchor application in Tunnel - Sinorock

In slope projects, self drilling rock anchors can be used as soil nail support, slope protection barrier, falling rock protection, retaining wall, embankment stability, roadbed reinforcement and other different application scenarios.

The self drilling rock anchors can also be used as new building pile foundation, existing building structure repair, tower foundation, bridge reinforcement, soundproof wall foundation, protective screen pile foundation, anti-floating pile foundation, retaining beam anchoring and other different structural scenes.

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