¿What is an expandable rock bolt?
It is an essential anchoring element in tunnel construction, underground mines, and geotechnical engineering. The expandable rock bolt works as an active support system for the rock mass. Its role is to enhance stability by preventing the detachment of rock blocks from walls and ceilings and the collapse of galleries.
Manufactured with high yield strength steel for maximum quality, strength, and durability, the expandable rock bolt enables the completion of even the most demanding anchoring tasks. It can withstand high tensile loads while ensuring the safety of the equipment operating underground
The expandable rock bolt is composed of an omega-shaped tube and a ferrule welded to each end, one of them perforated to allow the expansion of the rock bolt. Its manufacturing involves the use of complex automated technical systems to meet demanding quality standards.
The expandable rock bolt is one of the most effective and safest devices for rock mass stabilization in underground mining and tunnel construction.
Technical Specifications of the expandable rock bolt
The technical specifications of the expandable rock bolt can be grouped according to:
- The tube has a variable length that can range from 1.5 to 6 m, with a thickness of 2-3 mm.
- The breaking load that an expandable rock bolt can withstand varies between 120 kN and 240 kN.
- The inflation pressure applied to the inside of the steel tube to make it expand and fit the hole drilled in the rock also depends on the type of bolt and its diameter. It is usually between 240 and 300 bars to reach the desired tension. To ensure correct inflation and installation of the bolts, special pumps are used that provide high-pressure water flow.
Advantages of the expandable rock bolts for underground mining and tunnel construction
The expandable rock bolts are placed in the ceiling and walls of the excavations, forming a mesh that reinforces the rock mass and distributes the tensions generated.
The expandable rock bolts have several advantages over other ground support systems. Some of these advantages are:
- Quick and easy to install, which reduces time and saves operation costs.
- Adaptable to different types of rock, from the softest to the hardest, since they are flexible, expanding and adjusting to fit the hole.
- They are capable of withstanding high tensile loads, which improves excavation safety.
- They are compatible with other ground support systems, such as wire mesh or gunite, which increases the effectiveness of the reinforcement.
The installation process is very simple:
- Drill the hole in the rock slightly deeper than the bolt.
- Insert the expandable rock bolt into the hole.
- Inject water at the appropriate pressure so that the bolt expands and makes contact with the walls of the hole.
- Wait for complete expansion to secure the rock and remove the inflation pump nozzle.
In summary, the expandable rock bolt is an essential anchoring element that ensures stability and safety in tunnels, underground mines, and geotechnics. With the highest quality, it can adapt to different rock surfaces while supporting an enormous load capacity. All these features make it a safety, productivity, and efficiency ally for those responsible for mining operations and underground works
About Onix Underground
We are specialists in expandable rock bolt and underground support systems. Hundreds of thousands of our expandable rock bolts support rock masses in mines and tunnels around the world, ensuring the safety of people and work equipment. Our experts are at your service to advise you and offer you solutions of the highest quality, productivity and efficiency for your mining operations and underground works. Connect with our experts.
