R51 Self-Drilling Anchor Bar for Heavy Ground Support
R51 self-drilling hollow anchor bar for heavy slope stabilization, excavation support, tunnel portals and micropile-style reinforcement.
| Designation | R51L / R51N / R51S hollow self-drilling anchor bar |
| Outer Diameter | 51 mm |
| Typical Inner Diameter | 30-38 mm depending on variant |
| Typical Yield Load | About 450-730 kN |
| Typical Ultimate Load | About 550-930 kN |
| Typical Weight | About 6.0-9.4 kg/m |
| Installation | Self-drilling with grout injection through hollow core |
| Main Use | Heavy slopes, tunnel portals, deep excavations, micropile reinforcement |
R51 high-capacity hollow self-drilling anchor bar for heavy slopes, tunnel portals, excavation support and micropile-style reinforcement.
Product Overview
R51 self-drilling anchor bars are selected when the project needs higher tensile capacity, larger grout body and stronger support than standard R32 systems. They are common in heavy slope support, deep excavation works and weak tunnel portal zones.
The 51 mm hollow threaded bar drills into the ground with a sacrificial bit, then remains as the structural reinforcement. Grout is delivered through the center and bonds the anchor to the surrounding ground.
R51L, R51N and R51S variants allow the buyer to balance internal bore size, wall thickness, grout flow and load capacity according to project design.
Product Image Gallery
Real anchor product images from the current SunSea Steel media library, showing hollow bars, threaded profiles, grouting anchor rods and accessory details.
Technical Specifications
| Designation | R51L / R51N / R51S hollow self-drilling anchor bar |
|---|---|
| Outer Diameter | 51 mm |
| Typical Inner Diameter | 30-38 mm depending on variant |
| Typical Yield Load | About 450-730 kN |
| Typical Ultimate Load | About 550-930 kN |
| Typical Weight | About 6.0-9.4 kg/m |
| Installation | Self-drilling with grout injection through hollow core |
| Main Use | Heavy slopes, tunnel portals, deep excavations, micropile reinforcement |
Applications and Ground Conditions
Heavy slope support
Used where stronger soil nails or rock bolts are required.
Tunnel portals
Useful for weak entrance zones, shallow cover and fractured ground.
Micropile reinforcement
Suitable for foundation support and underpinning where design allows hollow bar micropiles.
Deep excavation
Provides higher capacity and larger grout body for retaining works.
Performance Advantages
Higher tensile capacity
R51 offers substantially more capacity than R32 in demanding ground support.
Large grout channel
The hollow core supports efficient grout delivery and bonded column formation.
Long anchor capability
Couplers allow sectional installation for deeper reinforcement.
Robust accessories
Heavy plates, nuts and drill bits can be matched to the R51 system.
Selection Guide
Choose R51 for higher load requirements, difficult ground, longer anchors and applications approaching micropile-type reinforcement.
| R51L | Larger inner diameter option where grout flow is important. |
|---|---|
| R51N | Balanced option for many heavy support works. |
| R51S | Higher steel section for stronger tensile capacity. |
| Project check | Confirm rig torque, bit type, plate size and design load before ordering. |
Quality Control and Installation Checks
Material and load verification
Confirm bar designation, wall thickness, yield load, ultimate load and weight per meter before production. Mill test certificates can be supplied for export orders.
Thread and coupler fit
Thread profile, coupler engagement, nut fit and plate compatibility should be checked as a complete system rather than separate parts.
Grouting control
Record grout mix, pressure, volume, return flow and curing time. Proper grout filling is essential for bond strength and corrosion protection.
Site acceptance
Installed length, drilling depth, bit diameter and accessory quantity should be recorded for each anchor position.
Accessories, Packaging and Export Supply
Matched accessory kits
Bars can be supplied with sacrificial drill bits, couplers, nuts, plates and centralizers according to project bill of materials.
Export packaging
Bundles are prepared for long-distance sea freight, container loading and jobsite handling.
Custom lengths
Standard and project-specific lengths are available. Couplers support staged installation in confined working areas.
Documentation
Packing list, commercial invoice, mill test certificate and inspection records can be prepared according to order terms.
Why Choose SunSea Steel
- Real anchor product images from the current media library, not generic placeholders.
- Specification-driven quotation covering bar, bit, coupler, nut, plate and centralizer.
- Support for R25, R32, R38, R51, T76 and project-specific self-drilling anchor systems.
- Export-oriented packaging and documentation for international buyers.
- Technical communication focused on ground condition, load requirement and installation method.
- Responsive quotation support through email and WhatsApp template variables.
Frequently Asked Questions
What is R51 self-drilling anchor bar used for?
R51 is used for heavy slope support, tunnel portals, deep excavation support and micropile-style reinforcement.
What load range is typical for R51 self-drilling anchor bar?
Typical R51 reference values are about 450-730 kN yield load and about 550-930 kN ultimate load depending on variant.
Can the hollow anchor bar be grouted through the center?
Yes. Cement grout is injected through the hollow core and exits near the sacrificial drill bit, filling the annular space around the bar.
Which accessories should be ordered with the anchor bar?
A complete order usually includes drill bits, couplers, nuts, bearing plates and centralizers matched to the bar thread and ground condition.
Can self-drilling anchors be used in collapsing boreholes?
Yes. The bar drills and remains in place, so installation does not depend on maintaining a stable open borehole before inserting reinforcement.
How do I choose between R32, R38, R51 and T76?
Selection depends on design load, required length, ground condition, borehole diameter, grout volume, equipment capacity and corrosion protection requirement.
Can the surface be galvanized or coated?
Hot-dip galvanizing, epoxy coating or project-specified corrosion protection can be discussed for permanent works.
What information is needed for quotation?
Send anchor size, length, quantity, design load, drill bit type, plate size, coupler quantity, ground condition and destination port.
Request Technical Support and Quotation
Send your anchor size, length, quantity, design load, ground condition, drill bit type, plate size, coating requirement and destination port. We will match the hollow anchor bar, drill bit, coupler, nut, plate and centralizer as a complete self-drilling anchor system.