In a landmark slope stabilization project for a large-scale hydropower station, SupAnchor’s Grade 75 self-drilling hollow anchor bars have been deployed to reinforce fractured rock masses and unstable soil layers. The project, located in a mountainous region with complex geological conditions including weathered granite and active fault lines, required a robust reinforcement system that could be installed quickly while providing long-term stability.
Traditional solid threaded bars faced limitations in this environment due to difficult drilling conditions and inconsistent grout bond. SupAnchor’s self drilling anchor system offered a compelling alternative by combining drilling, grouting, and anchoring in a single pass, drastically reducing installation time and improving load transfer.
The Grade 75 bars, manufactured to ASTM A615 standards, are designed with a continuous T-thread profile that provides a relatively higher rib area, significantly enhancing bond performance with the surrounding grout and rock. This feature is critical in fractured ground where reliable anchorage depends on maximizing mechanical interlock.
Key mechanical properties of the Grade 75 self-drilling hollow bar anchor include:
| Property | Value |
|---|---|
| Yield Load | 147 kN (33 kips) |
| Ultimate Load | 196 kN (44 kips) |
| Elongation | ≥ 6% |
| Weight | 2.6 kg/m (1.75 lbs/ft) |
| Thread Orientation | Left-hand |
During installation, the bars are drilled into the slope using a rotary-percussive hammer with a disposable drill bit attached to the tip. As drilling progresses, neat cement grout is injected through the hollow bar under controlled pressure, permeating fissures and consolidating the ground. The left-hand thread orientation helps prevent accidental unscrewing of couplings during the drilling and grouting process.
The Grade 75 hollow bar anchor’s compatibility with SupAnchor’s existing R and T thread product lines allows contractors to mix and match components without additional training or equipment changes. This interchangeability reduces inventory complexity and enhances operational flexibility on multi-phase sites.
Corrosion protection is achieved through either a hot-dip galvanizing or an epoxy coating applied on-site, depending on the environmental aggression level. For this hydropower project, a 100-micron zinc coating was specified to withstand high humidity and occasional acidic runoff.
As global infrastructure investment surges—particularly in renewable energy and transport—the need for efficient, reliable geotechnical reinforcement systems has never been greater. The self-drilling anchor bolt concept, once a niche technology, is now mainstream for projects where time, safety, and geological uncertainty demand innovative solutions.
Unlike conventional drill-and-grout bolts that require a separate drilling casing, these bars eliminate the risk of hole collapse in unconsolidated formations. This makes them ideal for tunneling, mining, and slope stabilization where drill rig availability and cycle time are critical. In the hydropower sector, where dam abutments and reservoir slopes often exhibit poor rock quality, the system’s ability to create a deep soil nail or ground anchor in one operation delivers measurable gains in schedule and cost.
The Grade 75 series specifically addresses the mid-range load requirements common in secondary reinforcement, such as wire mesh clamping and light retaining walls, while still offering the toughness needed for dynamic loading from blasting or seismic events. Its controlled yield and high elongation provide ductile behavior that is essential in active seismic zones.
SupAnchor has built its reputation as a leading soil nail system manufacturer and ground anchor bolt factory through continuous R&D and ISO-certified manufacturing. The company’s technical center works closely with geotechnical consultants and contractors to tailor anchoring solutions to specific project demands, from custom lengths and couplers to specialized corrosion protection packages.
With successful installations in over 30 countries, SupAnchor’s self drilling anchor system is recognized for its reliability and engineering support. The company actively participates in international conferences and contributes to technical guidelines, reinforcing its role as a collaborative partner rather than a mere supplier.
For this hydropower project, SupAnchor provided on-site training and continuous monitoring advice, ensuring that the self drilling anchor bolts met both the design specifications and the daily productivity targets. The result is a stable slope, a satisfied client, and another strong reference in the growing portfolio of geotechnical reinforcement systems.
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