In the demanding world of underground construction and geotechnical engineering, the ability to efficiently stabilize weak ground is critical. SupAnchor, a leading manufacturer of ground control solutions, has introduced the SupFRP® GFRP SDA Bolt, a state-of-the-art self drilling anchor system that combines drilling, grouting, and anchoring into a single operation. Designed for soft rock, clay soil, and other challenging conditions, this innovative hollow bar anchor offers significant advantages for tunnel face stabilization, slope reinforcement, and general ground support.
The new bolt addresses common challenges faced by contractors working in loose or unstable formations, where traditional drilling and anchoring methods can be time-consuming and prone to hole collapse. By integrating a hollow core that allows simultaneous flushing and grouting, the SupFRP® GFRP SDA Bolt ensures fast installation and reliable load transfer, reducing project timelines and enhancing safety.
The SupFRP® GFRP SDA Bolt is a drill-and-grout bolt engineered for permanent applications. Its installation process is streamlined into three essential steps: drilling, flushing, and grouting. The bolt itself serves as the drill rod, with a disposable drill bit attached to its tip. As the bolt is rotated and advanced into the ground, water or air is pumped through the central hollow core to flush out cuttings and cool the bit. This simultaneous flushing prevents clogging and ensures a clean borehole, which is particularly important in cohesive soils or fractured rock.
Once the desired depth is reached, the drilling is stopped, and grout is injected through the same central hole under pressure. The grout fills the annular space between the bolt and the ground, as well as any cracks or voids in the surrounding formation. This creates a continuous, full-length bond that transfers loads from the ground to the bolt, providing immediate and long-term reinforcement. The entire process is completed in a single pass, eliminating the need for separate drilling and anchor installation equipment, and significantly reducing installation time.
Because the bolt is self-drilling, it can be installed through overburden, loose rock, or even boulders without the risk of hole collapse. This makes it an ideal solution for geotechnical reinforcement systems in difficult ground conditions where conventional anchors would require casing or staged drilling.
The SupFRP® GFRP SDA Bolt is available in four standard diameters—25 mm, 28 mm, 32 mm, and 38 mm—with ISO-compliant thread profiles (R25, R28, R32, R38) to ensure compatibility with standard drilling equipment. The bolt's unique waved thread structure provides high torque resistance and superior bonding with grout, while the central hole enables efficient flushing and grouting.
Key technical parameters for the four models are summarized in the table below:
| Model | Outside Diameter (mm) | Internal Diameter (mm) | Guaranteed Tensile Load (kN) | Torsion Strength (Nm) | Weight (kg/m) | Thread Type (ISO) |
|---|---|---|---|---|---|---|
| H25S | 25 | 12 | 220 | 180 | 0.63 | R25 |
| H28S | 28 | 14 | 280 | 250 | 0.86 | R28 |
| H32S | 32 | 15 | 365 | 360 | 0.99 | R32 |
| H38S | 38 | 20 | 490 | 450 | 1.33 | R38 |
These specifications demonstrate the bolt's robust performance under demanding conditions. The guaranteed tensile loads range from 220 kN to 490 kN, providing high end loading capacity for permanent support. The torsion strengths of up to 450 Nm ensure that the bolt can withstand the high rotational forces encountered during drilling without failure. The lightweight design—ranging from 0.63 kg/m to 1.33 kg/m—facilitates easy handling and reduces transportation costs, making it an attractive option for large-scale projects.
Additionally, all models feature a tensile E-modulus of 45 GPa and an ultimate strain of 2.0%, offering a balance between stiffness and ductility. The nominal cross-sectional areas in the core (250–540 sq. mm) are optimized for resin or cement grout injection, ensuring a strong mechanical interlock with the surrounding ground. The waved thread structure enhances the bond strength, which is critical for geotechnical reinforcement systems in dynamic environments.
The SupFRP® GFRP SDA Bolt is specifically designed for applications where ground conditions are poor and rapid installation is essential. Its self drilling anchor bolt capabilities make it ideal for:
The hollow core design allows for water flushing during drilling, which cleans the hole and cools the bit, thereby extending tool life and improving drilling efficiency. Once the desired depth is reached, grout is injected through the same central hole under pressure, filling the annular space and any voids or fractures in the surrounding ground. This process ensures a continuous bond along the entire length of the bolt, creating a robust ground anchor bolt factory solution that performs reliably over the long term.
One of the standout features of this product is its cuttability. Unlike steel anchors, the GFRP (Glass Fiber Reinforced Polymer) material can be easily cut with standard excavation equipment. This is particularly advantageous when drifting or enlarging tunnels, as it prevents damage to machinery and reduces downtime associated with removing protruding steel bars. The cuttability also contributes to a safer working environment by eliminating the risk of sparks and reducing the weight of the support system.
In addition to cuttability, GFRP offers excellent corrosion resistance, making it suitable for use in aggressive environments such as coastal areas, mines with acidic water, and tunnels affected by stray currents. The material is also non-magnetic and electrically non-conductive, which is beneficial for projects where electromagnetic interference must be minimized. Furthermore, GFRP has a high strength-to-weight ratio, which reduces handling effort and transportation costs—a significant advantage for remote project sites.
The SupFRP® GFRP SDA Bolt is available in lengths from 2 to 11 meters, providing flexibility for various project requirements. Couplers can be used to extend the bolts to greater depths if needed, and the system is compatible with standard drilling rigs and grouting pumps, minimizing the need for specialized equipment.
The introduction of this advanced self drilling anchor system comes at a time when global infrastructure development is accelerating, particularly in the fields of tunneling, mining, and slope remediation. Projects in urban areas often encounter complex ground conditions, including soft soils, high groundwater, and existing utilities, which demand efficient and reliable ground support solutions. The SupFRP® GFRP SDA Bolt addresses these challenges by offering a single-pass installation method that reduces construction time and labor costs.
Compared to traditional ground support methods, such as driven spiles or grouted rebar, the self drilling anchor bolt eliminates the need for a separate drill hole and casing, thereby preventing hole collapse in loose ground. This not only improves safety but also enhances the quality of the installed anchor, as the grout is injected under pressure and fully encapsulates the bolt. The result is a more consistent and higher-capacity geotechnical reinforcement system that can be relied upon for permanent applications.
From a market perspective, the product aligns with the growing demand for non-corrosive, lightweight, and durable anchoring solutions. GFRP materials offer excellent resistance to chemical attack and electromagnetic interference, making them suitable for use in corrosive environments such as coastal areas, mining operations with acidic water, and tunnels with stray currents. The high strength-to-weight ratio of GFRP also reduces handling effort and transportation costs, which is a significant advantage for remote project sites.
SupAnchor has established itself as a trusted soil nail system manufacturer and ground anchor bolt factory with a strong focus on research and development. The company's products are manufactured under strict quality control procedures and meet international standards, including ISO certifications for thread profiles and material properties. By continuously innovating, SupAnchor aims to provide the construction industry with safe, efficient, and cost-effective ground support solutions.
The launch of the SupFRP® GFRP SDA Bolt underscores SupAnchor's dedication to engineering excellence. With its combination of high torque resistance, high end loading, and ease of installation, this product is poised to become a preferred choice for contractors and engineers worldwide. As infrastructure projects become increasingly complex, the ability to rapidly and reliably secure unstable ground will be a key factor in project success, and SupAnchor is at the forefront of this technological evolution.
For more information about the SupFRP® GFRP SDA Bolt and other ground support products, visit SupAnchor's official website or contact their technical sales team.
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