What Is Self-drilling Hollow Rock Bolt?


In the realm of construction and civil engineering, rock bolts have long been a trusted method for reinforcing various structures and stabilizing geological formations. Among the evolution of these bolts, one notable innovation is the self-drilling hollow rock bolt. This article delves into the intricacies of self-drilling hollow rock bolts, exploring their definition, components, applications, advantages, and considerations in contemporary construction practices.

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Understanding Self-Drilling Hollow Rock Bolts

Definition and Components

A self-drilling hollow rock bolt is characterized by its ability to simultaneously drill and grout while being installed. This eliminates the need for separate drilling and grouting processes, streamlining the installation procedure. Comprising a sacrificial drill bit, steel hollow bar, coupler, plate, and nut, this bolt system facilitates efficient anchoring and grouting in challenging geological conditions.


The self-drilling hollow rock bolts are divided into two patterns, R thread and T thread.

R thread: The thread complies with the international standard ISO 10208, which can match different drilling rigs.

T thread: The thread contains an arc-shaped part and a flat part. Thus, the cement slurry will bond better to the steel hollow bar to enlarge the bonding force.

How They Work

Self-drilling hollow rock bolts function by utilizing the sacrificial drill bit to penetrate hard rock or soil, creating a path for the subsequent grouting process. As the bolt advances, it effectively fills the void with grout, providing reinforcement and stability to the surrounding structure or geological formation. This integrated approach to drilling, grouting, and anchoring enhances construction efficiency and ensures reliable structural support.

Applications of Self-Drilling Hollow Rock Bolts

Tunnel and Underground Project

In tunneling and underground projects, self-drilling hollow rock bolts play a crucial role in initial support and stabilization. These rock bolts provide high-pressure grouting to fortify soil or rock masses, ensuring surface stability and structural integrity within tunnels. According to the types of support in the tunnels, self-drilling hollow rock bolt can be divided into fore piling, radial support, tunnel-face support, locking the foot support and reinforcement of the tunnel portal.

Ground and Foundation Project

For ground and foundation projects, self-drilling hollow rock bolts serve as versatile solutions for micro-piling and structural reinforcement. These rock bolts effectively transfer pressure, tension, or periodic loads to the surrounding soil, limiting deformation and enhancing foundation stability. They can 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.

Slope Stabilization Project

In slope stabilization endeavors, self-drilling hollow rock bolts offer robust anchoring systems to mitigate geological hazards and prevent slope instability. Slope stabilization is ensured by the entire anchoring system itself subjected to tensile and shear forces. It can be used as soil nail support, slope protection barrier, falling rock protection, retaining wall, embankment stability, roadbed reinforcement and other different application scenarios.

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Advantages of Self-Drilling Hollow Rock Bolts

Efficiency in Installation

The integrated drilling, grouting, and anchoring capabilities of self-drilling hollow rock bolts significantly enhance installation efficiency. By eliminating the need for separate drilling and grouting operations, these bolts streamline the construction process, reducing labor time and costs associated with traditional bolt installation methods.

Increased Safety

The reliability and effectiveness of self-drilling hollow rock bolts contribute to enhanced safety in construction projects. By providing immediate reinforcement and stabilization during installation, these bolts minimize the risk of structural failures and geological hazards, ensuring a secure working environment for construction personnel.

Versatility in Various Geological Conditions

One of the key advantages of self-drilling hollow rock bolts is their adaptability to diverse geological conditions. Whether encountering broken rock formations, loose soils, or challenging terrain, these bolts offer versatile solutions for anchoring, grouting, and stabilization, making them suitable for a wide range of construction applications.

Considerations and Challenges


While self-drilling hollow rock bolts offer numerous benefits, their initial cost may be higher compared to traditional bolt systems. However, the long-term savings in labor and time, coupled with enhanced construction efficiency, often justify the investment in these rock bolt solutions.

Maintenance Requirements

While self-drilling hollow rock bolts provide durable and reliable reinforcement, regular maintenance is essential to ensure long-term performance and structural integrity. Periodic inspections and maintenance activities, such as grout testing and bolt reinforcement, are necessary to mitigate potential issues and prolong the service life of these bolt systems.


Self-drilling hollow rock bolts represent a significant advancement in construction technology, offering integrated solutions for drilling, grouting, and anchoring in various geological conditions. From tunneling and ground projects to slope stabilization endeavors, these bolts provide efficient, safe, and versatile solutions for structural reinforcement and stability. By understanding the advantages, applications, and considerations of self-drilling hollow rock bolts, construction professionals can make informed decisions and ensure successful project outcomes. For reliable self-drilling hollow rock bolts and expert solutions, contact Sinorock at sinorock@sinorockco.com and take your construction projects to new heights.

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