In the rugged terrain of the Alps, a major railway tunnel project faced severe ground instability due to fractured rock and high groundwater ingress. Traditional support methods proved time-consuming and unreliable, prompting contractors to seek a more efficient solution. SupAnchor, a leading manufacturer of self drilling anchor systems, supplied its newly upgraded SupShell Expansion Rock Bolt System, which combines immediate mechanical anchorage with subsequent grouting to stabilize the excavation face quickly and safely. The project's demands for rapid installation and long-term reliability made this self drilling anchor system an ideal choice.
The project, involving over 10 kilometers of tunneling, required a support system that could be installed rapidly without compromising safety. The SupShell system's expansion shell hollow anchors, made from high-quality steel conforming to EN 10083, provided the answer. These anchors are designed for strata control, delivering immediate load-bearing capacity upon installation and facilitating fast, complete grouting through their hollow core. The system's plastic sealing element prevents grout leakage, ensuring full encapsulation of the bolt and enhancing its corrosion resistance.
The SupShell Expansion Rock Bolt System is a drill-and-grout bolt that integrates drilling, anchoring, and grouting in a single pass. Its design allows the bolt to be drilled into the ground, then expanded to grip the rock, and finally grouted through a central hole. This process not only speeds up installation but also ensures a full bond along the entire bolt length, enhancing long-term stability. This drill-and-grout bolt eliminates the need for separate drilling and anchoring operations, significantly reducing construction time and labor costs.
Key technical specifications include five models—R25, R28, R32, R32, and R32—each paired with expansion shells of different sizes to accommodate various ground conditions. The table below summarizes the main parameters:
| Expansion Shell Model | Specification | Outside Diameter (mm) | Drilling Hole Diameter (mm) | Length (mm) | Weight per Meter (kg/m) | Thread Type |
|---|---|---|---|---|---|---|
| R25 | R25/EX36 | 36 | Φ40-Φ42 | 132 | 0.62 | ISO 10208 / R25, R28, R32 |
| R28 | R28/EX40 | 40 | Φ44-Φ46 | 136 | 0.84 | |
| R32 | R32/EX44 | 44 | Φ48-Φ50 | 135 | 0.82 | |
| R32 | R32/EX46 | 46 | Φ50-Φ52 | 176 | 1.2 | |
| R32 | R32/EX48 | 48 | Φ52-Φ54 | 165 | 1.45 |
These specifications are crucial for engineers to match the bolt to the ground conditions. For instance, the R32/EX48 model, with an outside diameter of 48 mm and a drilling hole requirement of 52-54 mm, offers high load capacity and is suitable for deep tunnels with high stress. The lighter R25/EX36 model is ideal for smaller tunnels or where drilling equipment has lower torque. All models feature a thread type conforming to ISO 10208, ensuring compatibility with standard drill rods and accessories. The self drilling anchor bolt's hollow design allows for efficient grout injection, while the expansion shell provides immediate mechanical interlock with the rock mass.
In addition to mechanical strength, the SupShell system includes a plastic sealing element that prevents grout leakage during injection, ensuring the drill hole is completely filled. This results in a robust geotechnical reinforcement system that combines both mechanical and chemical anchorage. The bolts are made of CK45 steel, known for its toughness and wear resistance, and a galvanized option under ISO 1461 is available for corrosion protection in aggressive environments. This geotechnical reinforcement system is essential for projects needing long-term stability in corrosive or high-moisture conditions.
The system's features provide significant advantages:
The SupShell Expansion Rock Bolt System is versatile, finding applications in tunneling, mining, slope stabilization, and underground construction. As a self drilling anchor bolt, it eliminates the need for separate drilling and anchor installation steps, reducing downtime and labor costs. This hollow bar anchor is particularly effective in weak or collapsing ground where conventional drilling methods fail, as the bolt can be drilled and grouted in one continuous operation. The hollow bar anchor's central hole allows the grout to flow from the bottom up, filling all voids and creating a strong bond with the surrounding soil or rock.
In the mining sector, where time is critical, the system's ability to provide immediate anchorage allows miners to advance faster without waiting for grout to cure. For infrastructure projects, the SupShell system helps meet strict safety regulations by providing reliable ground support from the moment of installation. The global market for ground anchor systems is expanding, driven by urbanization and the need for resilient infrastructure. SupAnchor's products, including this expansion rock bolt system, are positioned to meet this demand with high-quality, cost-effective solutions.
As a soil nail system manufacturer and ground anchor bolt factory, SupAnchor adheres to international standards such as EN 10083 for steel quality and ISO 1461 for galvanization, ensuring that every bolt performs reliably under harsh conditions. The company's commitment to innovation is reflected in the SupShell system's design, which integrates feedback from field engineers to optimize performance. The expansion rock bolt system's versatility makes it suitable for both temporary and permanent support applications, from emergency repairs to large-scale infrastructure projects.
SupAnchor has established itself as a trusted name in the geotechnical industry, supplying self drilling anchor systems to projects across Europe, America, and Asia. The company's state-of-the-art manufacturing facilities and rigorous quality control processes ensure that each SupShell bolt meets the highest standards. With a focus on R&D, SupAnchor continuously improves its products to address evolving ground support challenges. The company's collaborative approach involves working closely with contractors and consultants to tailor solutions to specific project needs. SupAnchor's self drilling anchor bolts are recognized for their durability and performance in demanding environments.
Looking ahead, SupAnchor plans to expand its product line and increase its global footprint, bringing advanced geotechnical reinforcement systems to more projects worldwide. The SupShell Expansion Rock Bolt System is a testament to the company's ability to deliver professional, innovative, and collaborative solutions for safe and efficient construction. As a leader in geotechnical reinforcement systems, SupAnchor continues to set benchmarks for quality and reliability in the industry.
For more information about the SupShell Expansion Rock Bolt System and other SupAnchor products, visit www.supanchor.com.
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