At a major hydropower station construction site, engineers faced significant geotechnical challenges: steep, weathered rock slopes prone to instability, fractured formations with high groundwater ingress, and a tight construction schedule. Traditional anchoring methods requiring pre-drilled holes and separate casing proved slow and costly. To overcome these obstacles, the project team turned to SupAnchor's self drilling anchor system, specifically the Grade 75 self-drilling hollow anchor bars. Supplied by SupAnchor, a leading soil nail system manufacturer and ground anchor bolt factory, these bars enabled rapid, reliable slope stabilization while minimizing disruption to the surrounding environment.
The hydropower station slope stabilization project involved securing rock masses along reservoir banks and access roads. The geology consisted of highly fractured shale and sandstone with zones of loose overburden, making conventional drilling and grouting operations inefficient. Collapsing boreholes frequently trapped drill rods, and the need for temporary casing added significant time and expense. SupAnchor's Grade 75 hollow bar anchor offered a drill-and-grout bolt solution: the hollow bar itself serves as the drill rod, injection pipe, and reinforcement element in a single pass. This self drilling anchor bolt eliminates the need for a separate casing, reduces drilling time, and ensures immediate load transfer after grouting.
On site, crews used standard rotary-percussive drilling rigs to install the bars directly through unstable ground. Grout was pumped through the hollow core under pressure, filling the annular space and consolidating the surrounding rock. The continuous T-thread profile along the entire bar length provided a mechanical interlock with the grout, significantly enhancing bond strength compared to smooth or deformed bars with limited thread contact. This approach allowed the project to stabilize over 12,000 square meters of slope face ahead of schedule, according to project engineers.
The SupAnchor Grade 75 self-drilling hollow anchor bars are manufactured to ASTM A615 standards, ensuring consistent mechanical properties and weldability. Unlike traditional solid bars, the hollow design enables simultaneous drilling and grouting, reducing installation steps and improving ground consolidation. Key specifications include:
| Parameter | Value |
|---|---|
| Standard | ASTM A615 |
| Thread Design | Continuous T-thread (left-hand) |
| Elongation | ≥ 6% |
| Yield Load | Approx. 147 kN (33 kips) |
| Ultimate Load | Approx. 196 kN (44 kips) |
| Weight | Approx. 2.6 kg/m (1.75 lbs/ft) |
| Thread Orientation | Left-hand |
These parameters directly address the site-specific challenges. The relatively higher rib area of the T-thread design maximizes grout-to-bar bonding, achieving pull-out capacities that meet or exceed design loads in fractured rock. The yield load of 147 kN allows the bar to absorb significant deformation without failure, providing ductility in dynamic slope conditions. The elongation of at least 6% ensures the system can accommodate ground movement without brittle rupture, a critical factor in hydropower environments where reservoir level changes induce cyclic loading. The moderate weight of 2.6 kg/m facilitates handling and reduces equipment strain, while the left-hand thread orientation is fully compatible with SupAnchor's R and T thread self-drilling anchor products, enabling seamless integration with existing accessories such as couplers, nuts, and drill bits.
Moreover, the hollow core diameter is optimized for high-pressure grout injection, allowing effective permeation of fine fissures and voids. This geotechnical reinforcement system not only stabilizes the slope but also improves the overall integrity of the rock mass, reducing long-term maintenance requirements.
The use of self drilling anchor bolts is expanding across global infrastructure projects, driven by the need for faster installation, lower total cost, and improved safety in difficult ground conditions. In tunneling, mining, and foundation reinforcement, the drill-and-grout method eliminates the need for temporary casing and separate drilling operations, cutting project timelines by up to 40% compared to conventional anchoring. For contractors and asset owners, this translates into reduced labor costs, less equipment mobilization, and fewer environmental disturbances.
SupAnchor's Grade 75 bars are particularly suited for emergency slope repairs and remote site applications, where logistics and access constraints make traditional anchoring impractical. The ability to install with lightweight rigs and standard tooling expands the range of feasible projects, from urban retaining walls to high-altitude hydropower stations. As governments worldwide invest in renewable energy and transportation infrastructure, the demand for reliable hollow bar anchor solutions continues to grow. SupAnchor's products align with this trend, offering a geotechnical reinforcement system that meets international standards while adapting to diverse geological conditions.
SupAnchor has established itself as a professional and innovative supplier in the ground engineering sector. The company's research and development team continuously refines thread geometries, steel chemistries, and manufacturing processes to exceed performance benchmarks. All products, including the Grade 75 self-drilling hollow anchor bars, are produced under ISO 9001-certified quality management systems, with additional certifications for environmental and occupational health and safety. SupAnchor's global project portfolio spans over 40 countries, including major hydropower, tunneling, and mining ventures in Europe, North America, and Asia-Pacific.
By focusing on collaboration with geotechnical consultants and contractors, SupAnchor ensures that its self drilling anchor system not only meets technical specifications but also integrates smoothly with site workflows. The company's technical support team provides on-site training and custom design assistance, reinforcing its reputation as a trusted ground anchor bolt factory. This customer-centric approach, combined with robust engineering, positions SupAnchor as a partner of choice for complex slope stabilization and underground construction projects.
As the hydropower station slope stabilization project demonstrates, the SupAnchor Grade 75 self-drilling hollow anchor bars deliver reliable performance in demanding conditions. For more detailed specifications and project references, visit the official product page at SupAnchor.com.
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