In the high-stakes world of tunneling, slope stabilization, and mining, ground conditions often pose unpredictable challenges—fractured rock, high water pressure, and the need for rapid, reliable support. Contractors require solutions that not only secure the face but also withstand aggressive environments over decades. Addressing these demands, SupAnchor has officially launched its SupFRP® GFRP Hollow Injection Bolt, a next-generation self drilling anchor system that integrates the functions of a rock bolt, grouting pipe, and injection system into one lightweight, corrosion‑proof package.
Designed for both temporary and permanent applications, this innovative hollow bar anchor is already drawing attention from major infrastructure projects across Europe and North America, where durability and ease of installation are paramount. The bolt’s ability to remain in the borehole after injection, working together with a plate and nut, makes it a true all‑in‑one geotechnical reinforcement system.
At the core of the SupFRP® GFRP Hollow Injection Bolt is a unique combination of high tensile strength, pressure resistance, and cuttability—features rarely found together in conventional steel anchors. Made from glass fiber reinforced polymer (GFRP), the bolt offers exceptional corrosion resistance, making it ideal for permanent works in chemically aggressive soils or marine environments. Unlike steel, it is non‑conductive and electromagnetically neutral, adding safety in tunneling and mining applications.
The hollow design allows grout to be injected through the bolt at high pressure (up to 30 MPa in select models), ensuring complete encapsulation of the borehole and full bonding with the surrounding ground. This drill‑and‑grout bolt methodology eliminates the need for separate grouting pipes, speeds up installation cycles, and improves overall project quality. The bolt’s waved thread structure provides a mechanical interlock with the grout, achieving a bond strength that often exceeds the tensile capacity of the anchor itself.
Key performance parameters across the product range highlight its versatility:
| Model | Outer Ø (mm) | Inner Ø (mm) | Tensile Load (kN) | Pressure Resistance (MPa) | Weight (kg/m) |
|---|---|---|---|---|---|
| H22/230 | 22 | 8 | 230 | 18 | 0.58 |
| H25/300 | 25 | 8 | 300 | 30 | 0.79 |
| H32/360 | 32 | 15 | 360 | 5 | 1.20 |
| H38/490 | 38 | 20 | 490 | 5 | 1.50 |
All models are available in lengths from 2 m to 11 m, with left‑ or right‑hand thread options, and maintain a tensile E‑modulus of 45 GPa and ultimate strain of 2.0%. The lightweight nature—as low as 0.58 kg/m for the H22/230—reduces handling fatigue and allows faster installation without compromising load‑bearing capacity.
The SupFRP® GFRP Hollow Injection Bolt is engineered for a wide array of geotechnical challenges. Its primary applications include:
In tunneling, the drill‑and‑grout bolt technique significantly reduces the number of installation steps. Workers simply drill the hollow bar into the ground, then inject grout through it—no separate casing or post‑grouting tubes are needed. This self drilling anchor bolt approach saves time and improves safety by minimizing open boreholes. The high‑pressure injection capability (up to 30 MPa in the H25/300) ensures that grout penetrates even the smallest fissures, creating a watertight, reinforced soil‑nail system that is both temporary and permanent.
For soil nail system manufacturer partners and ground anchor bolt factory suppliers, the SupFRP® series offers a new level of flexibility. The bolts can be coupled to achieve virtually any length, and their corrosion‑free composition eliminates the risk of rust‑related expansion that can crack grout or rock over time.
As infrastructure spending surges worldwide—from high‑speed rail networks in Europe to hydropower tunnels in North America—project owners increasingly demand durable, low‑maintenance solutions. The GFRP hollow injection bolt aligns with these trends by offering a maintenance‑free, long‑life alternative to traditional steel anchors. Its non‑corrosive nature reduces life‑cycle costs and legal liability for future asset management.
The system also enhances on‑site safety. Low weight (some models are 70% lighter than equivalent steel bars) lowers the risk of handling injuries, while the integrated injection process eliminates the need for workers to switch between drilling, grouting, and tensioning equipment. Faster installation cycles allow contractors to advance tunnel profiles or stabilize slopes more quickly, cutting overall project schedules.
From an environmental standpoint, GFRP production has a lower carbon footprint than steel, and the elimination of secondary corrosion protection coatings reduces chemical waste on site. These factors make the self drilling anchor system an attractive choice for green‑building certification programs.
SupAnchor has long been recognized as a pioneer in self drilling anchor technology. With a strong R&D pipeline and ISO‑certified manufacturing facilities, the company has supplied thousands of projects in over 30 countries. The SupFRP® series embodies the brand’s commitment to Professional, Innovative, and Collaborative engineering—values that resonate with geotechnical consultants and contractors who demand reliable, field‑proven products.
The new GFRP hollow injection bolt has already been successfully deployed in challenging environments, including TBM tunnels through fractured gneiss and slope stabilization in seismically active regions. Project managers report that the bolt’s consistent quality and on‑time delivery from the factory have helped keep critical infrastructure projects on track.
Looking ahead, SupAnchor plans to expand the SupFRP® range with additional diameters and specialized accessories, further cementing its position as a leading ground anchor bolt factory and innovation partner for the global construction industry.
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