At a major hydropower station slope stabilization project in a mountainous region, engineers faced challenging geological conditions including highly fractured rock, water seepage, and steep cutting faces. The project required a reliable anchoring solution that could be installed quickly without sacrificing load capacity. SupAnchor supplied its Grade 75 self-drilling hollow anchor bars as a core component of the geotechnical reinforcement system. This self drilling anchor system was chosen for its ability to combine drilling, grouting, and anchoring in one operation, reducing installation time and enhancing safety on site. The project involved stabilizing a slope over 150 meters high, with alternating layers of weathered rock and competent granite, and the risk of localized rockfalls demanded a robust, corrosion-resistant anchoring solution.
The construction team used a drill-and-grout bolt technique with the hollow bar anchor, allowing grout to be injected through the bar during drilling. This method stabilized loose overburden and ensured full encapsulation of the anchor in the surrounding rock mass. The Grade 75 bars, produced to ASTM A615 standards, offered a continuous T-thread profile that improved bond performance in concrete and grout, a critical requirement for the project's long-term slope stability. Unlike traditional solid bars, the hollow core eliminated the need for a separate grouting tube, reducing installation steps and minimizing the chance of grout blockage in fractured ground. During the six-month construction window, over 1,200 Grade 75 anchors were installed at depths ranging from 9 to 15 meters, each anchor achieving full load transfer within 24 hours of grouting.
SupAnchor's Grade 75 self-drilling hollow anchor bars are engineered for demanding geotechnical applications. Key mechanical properties include an elongation of at least 6%, a yield load of approximately 147 kN (33 kips), and an ultimate load of approximately 196 kN (44 kips). The bars weigh about 2.6 kg/m (1.75 lbs/ft) and feature a left-hand thread orientation. These specifications are consistent with SupAnchor's R and T thread self-drilling anchor products, allowing for easy interchangeability and integration into existing systems.
| Parameter | Value |
|---|---|
| Standard | ASTM A615 |
| Thread Type | Continuous T-thread, left-hand |
| Elongation | ≥ 6% |
| Yield Load | ~147 kN (33 kips) |
| Ultimate Load | ~196 kN (44 kips) |
| Unit Weight | ~2.6 kg/m (1.75 lbs/ft) |
On the hydropower project, these technical parameters translated into direct engineering advantages. The high ultimate load capacity allowed designers to reduce the number of anchors required for the slope, cutting material and labor costs. The continuous T-thread increased the rib area, improving load transfer from the bar to the grout, which is especially important in fractured rock where bond strength can be unpredictable. The compatibility with existing R and T thread self-drilling anchor systems meant that contractors could use standard SupAnchor accessories such as couplers, nuts, and drill bits, streamlining logistics and reducing inventory complexity. Field tests confirmed that the bars achieved full bond strength within 24 hours of grouting, allowing for rapid progression of the slope stabilization work. The project site experienced heavy seasonal rainfall, which increased pore water pressure and the risk of slope failure. The continuous T-thread design helped to create a watertight grout column, reducing water ingress and enhancing long-term durability.
Self drilling anchor bolts are widely used in geotechnical reinforcement systems for slope stabilization, tunneling, and foundation reinforcement. In this hydropower project, the bars served as both temporary and permanent support elements, securing unstable rock blocks and preventing erosion-driven instability. The ability to drill and grout in a single pass minimized disturbance to the surrounding ground, a key factor when working near sensitive watercourses and existing infrastructure. The hollow bar anchor design also allowed for immediate installation of the bearing plate and nut, enabling the anchor to carry load almost immediately after grouting, which is critical for time-sensitive slope repair works.
The global infrastructure market increasingly demands anchoring solutions that reduce construction time and improve safety. The Grade 75 self drilling anchor system meets these needs by eliminating the need for a casing in collapsing ground and enabling immediate load transfer after grouting. Compared with traditional solid threaded bars, the hollow bar anchor offers a cost-effective alternative without compromising performance, particularly in fractured or water-bearing ground conditions. In tunneling projects, the self-drilling capability reduces the risk of borehole collapse, a common problem in soft ground or high-stress rock masses. For mining applications, the bars can be installed rapidly to secure roof and sidewalls, enhancing worker safety and operational continuity. In addition to slope stabilization, the same Grade 75 bars have been used for tunnel forepoling and as micropiles for bridge abutment support, demonstrating their versatility across different geotechnical contexts.
As a soil nail system manufacturer, SupAnchor has positioned its Grade 75 bars as a versatile component for projects ranging from urban deep excavations to remote hydropower plants. The consistent thread geometry ensures that contractors can rely on predictable torque and load behavior, reducing the risk of installation errors and enhancing overall project quality. The bars are also compatible with standard drilling equipment, reducing the need for specialized tooling and training. This adaptability has made SupAnchor a preferred supplier for projects where time, budget, and ground conditions demand a reliable, ready-to-use anchoring solution.
SupAnchor has built a reputation as a ground anchor bolt factory and international supplier of self-drilling anchor systems. With ISO-certified manufacturing facilities and a dedicated R&D team, the company continuously refines thread profiles and steel grades to meet evolving geotechnical challenges. The Grade 75 hollow bar is a result of this focus, offering improved elongation and bond characteristics while maintaining full compatibility with existing product lines. The company's engineers work closely with project consultants to optimize anchor spacing, length, and grouting parameters, ensuring that each installation meets the specified safety factors.
Across global projects in Europe, the Americas, and Asia, SupAnchor's self drilling anchor system has been deployed in highway tunnels, metro stations, and slope remediation works. The company's commitment to professional engineering support, innovative products, and collaborative project management has made it a preferred partner for contractors and consultants facing complex ground conditions. Recent projects include a high-speed rail tunnel in the Alps, a coastal highway retaining wall in Southeast Asia, and a large-scale open-pit mine in South America, all of which benefited from the reliability of SupAnchor's self-drilling hollow bars.
The successful application of Grade 75 self-drilling hollow anchor bars in the hydropower station slope stabilization project demonstrates SupAnchor's ability to deliver reliable, high-performance anchoring solutions under demanding site conditions. As infrastructure investment continues to grow, the combination of technical excellence and practical adaptability will remain central to the company's value proposition. By integrating advanced manufacturing with field-proven designs, SupAnchor continues to support the global construction industry with products that enhance safety, reduce costs, and accelerate project delivery.
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