In a major tunnel expansion project through the fractured rock mass of the Swiss Alps, engineers faced a critical challenge: the need for a rock support system that could provide immediate tensioning and permanent corrosion resistance in highly aggressive groundwater conditions. Traditional grouted anchors often suffered from corrosion-induced failures, leading to costly maintenance and safety risks. The project team turned to an innovative solution—SupAnchor’s newly launched SupCT Bolt System. This combination bolt, developed by the Chinese geotechnical specialist SupAnchor, is rapidly gaining attention across Europe and North America for its robust duplex protection and high ductility, promising to reshape rock support strategies in infrastructure, mining, and slope stabilization.

Duplex Corrosion Protection and Factory Preassembly Redefine Reliability

The SupCT Bolt System is a fully grouted combination bolt available in two primary categories: Steel Bolt (solid bar and hollow bar types) and GFRP Bolt (solid bar and hollow bar types). Its standout feature is the duplex corrosion protection—a hot-dip galvanized and epoxy powder-coated rebar encased in a plastic grouting pipe, fully embedded in cement mortar. This multi‑layer barrier ensures a service life of up to 150 years under the SupCoat treatment, eliminating the need for stainless steel components in all but the most extreme environments. Factory‑preassembled zinc‑coated expansion shells prevent thread corrosion, reduce on‑site labor, and simplify inventory management. Additionally, an optimized grouting design, with a short distance between the grouting pipe end and the expansion shell, guarantees complete borehole filling from the toe outward, while a leak‑proof bolt head prevents mortar splash during installation—significantly enhancing worker safety.

Technical Specifications Tailored for Demanding Ground Conditions

SupAnchor’s SupCT system addresses varying ground conditions with a range of models. The Steel Bolt series includes solid bars (SSB-M20, SSB-M22, SSB-M33) and hollow bars (SHB-R2715, SHB-R2712), offering yield loads up to 402 kN and ultimate loads up to 482 kN. The GFRP Bolt series—solid (GSB-R22, GSB-R25, GSB-R32) and hollow (GHB-R25, GHB-R28, GHB-R32)—provides permanent corrosion resistance with ultimate loads up to 560 kN, making it ideal for environments with high acidity or stray currents. All bolts are deliverable in lengths from 1.5 to 6.0 meters, and the bubble design of the plastic grouting pipe enhances pull‑out resistance by mechanically interlocking with the mortar. The following tables summarize key parameters:

Engineering Versatility and On‑Site Efficiency

Unlike conventional rock bolts that require separate immediate support and permanent anchoring components, the SupCT system serves both functions with a single installation. This drastically reduces cycle times in tunnels and mines. The bolts are delivered on pallets with factory‑installed expansion shells, preserving thread integrity and speeding up installation. Even in poor, soft rock, the system delivers reliable performance, though on‑site pull‑out tests are recommended to confirm anchor capacity under actual conditions. The dual‑certified corrosion protection (hot‑dip galvanization per NS‑EN‑ISO 1461 and epoxy powder coating per NS‑EN 13438) gives engineers confidence in aggressive environments—from subsea tunnels to chemical plants. Furthermore, the GFRP variants, with their electromagnetic neutrality and permanent corrosion resistance, are increasingly specified for rail transit and high‑voltage infrastructure where stray currents pose a risk to steel elements.

Market Impact: Raising the Bar for Geotechnical Reinforcement Systems

The global push for resilient infrastructure and deeper mining operations has intensified the demand for self drilling anchor systems and hollow bar anchors that combine speed with longevity. SupAnchor’s SupCT Bolt System directly addresses this need. By merging the ease of drill‑and‑grout bolts with an engineered duplex shield, the product minimizes long‑term maintenance and lifecycle costs. Infrastructure projects in Europe, where strict durability requirements (often 120‑year design life) are the norm, are ideal candidates for such a system. Mining operators in North America, faced with ever‑deeper ore bodies and corrosive groundwater, can also benefit from the reduced need for re‑support. The system’s wide range of load capacities and lengths ensures adaptability from shallow slope stabilization to deep shaft lining.

Industry analysts note that the integration of plastic grouting pipe technology with high‑strength steel or GFRP bars represents a significant step forward in geotechnical reinforcement systems. The bubble‑textured pipe surface, in particular, creates a mechanical lock with the cementitious grout, delivering pull‑out resistances that often exceed the bar’s yield strength. This innovation reduces reliance on resin cartridges and other time‑sensitive settlement methods, allowing more predictable and safer installations.

SupAnchor’s Global Footprint and Commitment to Quality

SupAnchor, a China‑based manufacturer with a growing international presence, has built its reputation on self drilling anchor bolt technology and soil nail system manufacturing. The company’s ISO‑certified facilities employ rigorous testing protocols aligned with European and American standards (DIN, ASTM, CSA, ACI). The SupCT system is the latest addition to a portfolio that already serves projects in over 30 countries. The company’s focus on collaborative design—working closely with consulting engineers and contractors—ensures that each bolt configuration is optimized for the specific geology and load requirements of the job site.

“We see the SupCT Bolt System as a direct response to the industry’s call for a truly permanent yet quickly installable rock bolt,” said a SupAnchor technical director. “By combining our expertise in hollow bar anchors and corrosion protection, we have created a product that not only meets but exceeds the most demanding specifications for underground and slope support.”

As infrastructure investments surge globally, the need for reliable underground support has never been greater. SupAnchor’s SupCT Bolt System stands out as a professional, innovative, and collaborative solution—engineered to protect workers, secure excavations, and extend the life of critical structures for generations.