Self Drilling Rock Bolts

Self drilling anchors are special type of rod anchors. Self-drilling anchor consists of a sacrificial drill bit, hollow steel bar of the appropriate outer and inner diameter and coupling nuts. The anchor body is made of a hollow steel tube with an outer round thread. Steel tube has the sacrificial drill bit at one end and the corresponding nut with a steel end plate. Self drilling anchor bolts are used in a way that hollow steel bar (rod) has a corresponding sacrificial drill bit on its top instead of a classic drill bit.

Product Description

The self drilling rock bolts consist of a hollow threaded rod and an attached drill bit that can perform drilling, anchoring and grouting in one operation. The hollow rods allow air and water to pass freely through the rods during drilling to remove debris, and are then injected with grout as soon as the drilling is complete. Grout fills the hollow bar and completely covers the entire bolt. Couplers can be used to connect hollow rods 

and extend bolt lengths, while nuts and plates can be used to provide the required tension.

JiuFu self drilling rock bolts are an anchoring solution suitable for unstable ground conditions (such as sand, gravel, silt and clay) and soft to moderately cracked rock formations. For projects facing such ground conditions, self-drilling anchors should be regarded as the main productivity solution. Self-drilling rock bolts do not require drilling, so they can be used even in soft rock conditions. Suitable for installation with mortar. The hollow steel bolt can also be used as an injection pipe for easy installation.

Especially recommended for the following applications:

1. Roof and wall bolts

2. Tunnel weak soil reinforcement

3. Tunnel foot pile, face, soft eye reinforcement

4. Reinforce soil and rock

5. Avalanche prevention barriers

6. Tunnel entrances, trenches, cutting and covering areas

7. Reinforce excavated roads, dams and slopes

8. Reinforcement of retaining walls and noise barriers

9. Foundation piles and support piles


Self Drilling Rock Bolts include:

A hex nut : The hexagonal nut is made of high-precision steel, and it is recovered to meet the strict requirements of the anchor specifications and underground work.

A load-bearing board: The load-bearing plate is a forged steel plate with a central hole, allowing hinges in all directions.

Extension coupling, if the anchor consists of multiple Anchor rod parts

Hollow anchor: The anchor rod has a hollow hole for flushing or drilling and grouting at the same time, and has thread for connecting standard drills.

Sacrifice bit

Galvanized anchor: All series of SDA rods and accessories provide hot-dip galvanized anti-corrosion protection.

Coupling box: The coupling box is made of thick-wall steel that is processed and surface hardening, and is used for high wear positions.



Installation of Self Drilling Anchor Bolts

The hollow steel bar is driven to the required depth by means of rotary percussive drilling. Injection is carried out through hollow steel bar. Injection mixture flows through the holes at the sacrificial drill bit and automatically stabilizes the drilled hole. Injection ends when the mixture begins to exit from drilled hole. The cement grout is most often used for injection of self-drilling anchor. The usual water-cement ratio ranges from 0,40 to 0,50. We carry acomprehensive range of various self drilling rock bolts; generally speaking, we have two categories as below:

R25N, R32L, R32N, R32S, R38N, R51N, T76N, T76S, T111N, T111S;

T30/16, T30/14, T40/16, T40/20, T52/26, T73/53, T73/45, T73/35, T103/78, T103/51; All self drilling rock bolts can be manufactured in different lengths, like 2 meters, 3 meters, 4meters, 6 meters or 9 meters. Both left hand thread and right hand thread areavailable upon customer's request. Besides, as a leading self drilling rock bolts supplier, JiuFu also provides Self Drilling Anchor Bolt, Friction Bolts Split Sets and Restressed Screw Thread Steel Bars with a complete range of accessories, including coupling sleeves, steelplates, nuts, centralizers, and various anchor bits. For detailed information, welcome to contact us!


Advantages of Self Drilling Rock Bolts System

Our Self Drilling Rock Bolts system has the following advantages:

Each of our anchor rods are made of high-quality steel and the most advanced technology to ensure that our quality meets international standards or even better.

The SDA Rock Bolt does not require casing drilling, and can complete drilling, grouting and anchoring at the same time.

Self Drilling Rock Bolts can be used for temporary support as well as permanent support in various applications such as tunnel support, micro-pile, and soil nailing.

The anchor of the standard full thread can be cut according to your requirements. The cut anchor rod can be connected through the coupling device. It is suitable for narrow work space.

Self Drilling Rock Bolts have high binding stress due to continuous R and T threads.

You may also want to know:

The Types of Rock Bolts 

How do self-drilling anchors stabilize broken slopes and rocks

How to Install Concrete Fasteners