Anchoring is widely used in tunnel for pre-support, slope, coast, mine, water conservancy projects, Building foundation, roadbed reinforcement and geological faulty treatment such as landslip, crack, and sink age, it’s irreplaceable in narrow construction environment.
Advantages & Components
Self Drilling Hollow Bar Anchor System
Comprised of a hollow threaded bar attached with a drill bit that performs drilling. The hollow bar allows air and water to freely pass through the bar during drilling to remove debris. After drilling at the required depth is completed, grout fills the hollow bar through the pressure and completely covers the entire bolt.
Coupler
The coupler can be used to join hollow bars and extend the bolt length, allowing the anchor to be elongated based on site requirements.
Plate and Nut
The plate and nut are installed according to their specific design requirements to provide secure tensioning.
Drill Bit
A wide range of drill bits is available to be selected based on the specific ground conditions encountered.
Technical Specifications
Hollow Anchor Bar Specifications
| Hollow Anchor Bar |
| Size |
Outer Dia. |
Inner Dia. |
Ultimate Load |
Yield Load |
Weight |
| (mm) |
(mm) |
(kN) |
(kN) |
(Kg/m) |
| S-R32/20 | 32 | 20 | 210 | 160 | 2.83 |
| S-R32/17 | 32 | 17 | 280 | 230 | 3.5 |
| S-R32/15 | 32 | 15 | 360 | 280 | 4 |
| E-R32/21 | 32 | 21 | 210 | 160 | 2.6 |
| E-R32/19 | 32 | 19 | 280 | 230 | 2.95 |
| E-R32/17 | 32 | 17 | 360 | 280 | 3.5 |
| E-R32/15 | 32 | 15 | 405 | 320 | 4 |
| C-R32/21 | 32 | 21 | 250 | 190 | 2.6 |
| C-R32/20 | 32 | 20 | 280 | 230 | 2.83 |
| C-R32/17.5 | 32 | 17.5 | 360 | 280 | 3.4 |
Coupler Specifications
| Coupler |
| Size |
Outer Dia. |
Length |
Weight |
Note |
| (mm) |
(mm) |
(Kg/pc) |
| SSR32 | 42 | 145 | 0.79 | With sealing structure |
| 42 | 160 | 0.86 |
| 42 | 190 | 1 |
| SER32 | 42 | 145 | 0.77 | Without sealing structure |
| 42 | 160 | 0.84 |
| 42 | 190 | 1 |
Drill Bit Selection Guide
| Drill Bit |
| Type |
Outer Dia. |
Weight |
Application Range (Advice) |
| (mm) |
(Kg) |
| Cast cross bit | R32/51 mm | 0.99 | Cast cross bit for sand and gravel |
| Steel cross bit | R32/51 mm | 0.88 | Hardened steel bit for loose to medium dense ground conditions |
| R32/76 mm | 2.87 |
| Steel 3 cutter bit | R32/76 mm | 2.65 |
| TC cross bit | R32/51 mm | 0.99 | TC insert bit for soft to medium rock formations |
| TC 3 cutter bit | R32/76 mm | 2.87 |
| Steel arched bit | R32/51 mm | 0.99 | Hardened arched bit for optimized geometry for unconsolidated soil with small boulders |
| TC arched bit | R32/51 mm | 0.99 | TC arched bit for optimized geometry for soft to medium rock formations |
| Steel button bit | R32/51 mm | 1.32 | Hardened button bit for unconsolidated rock with boulders |
| TC button bit | R32/51 mm | 1.43 | TC insert button bit for medium rock formation |
| EX bit | R32/51 mm | 0.88 | Hardened cross cut drill bit, suitable for majority of applications. |
| EXX bit | R32/51 mm | 1.1 | Hardest drill bit available, for strong rock and concrete footings. |
Hex Nut Specifications
| Hex Nut |
| Size |
Key Size |
Length |
Weight |
Hardness |
| (mm) |
(mm) |
(Kg/pc) |
(HRC) |
| SSR32 | 46 | 45 | 0.37 | 25-30 |
| 46 | 55 | 0.46 |
| 46 | 60 | 0.47 |
Domed Plate Dimensions
| Domed Plate |
| Size |
Dimensions |
Thickness |
Hole Dia. |
Weight |
| (mm) |
(mm) |
(mm) |
(Kg/pc) |
| R32-E | 150×150 | 8 | 35 | 1.3 |
| 150×150 | 5 | 35 | 0.85 |
| 150×150 | 6 | 35 | 1 |
| 150×150 | 10 | 35 | 1.7 |
| 175×175 | 8 | 35 | 1.9 |
| 200×200 | 8 | 35 | 2.6 |
| 200×200 | 10 | 35 | 3.52 |
| 200×200 | 12 | 35 | 2.94 |
Anchor Plate Dimensions
| Anchor Plate |
| Size |
Dimensions |
Thickness |
Hole Dia. |
Weight |
| (mm) |
(mm) |
(mm) |
(Kg/pc) |
| SER32 | 95×95 | 25 | 35 | 1.6 |
| 120×120 | 30 | 35 | 3.2 |
| 150×150 | 8 | 35 | 1.3 |
| 200×200 | 10 | 35 | 3.06 |
Frequently Asked Questions
What is the main benefit of a Self-Drilling Hollow Bar Anchor?
The main benefit is the combination of drilling, anchoring, and grouting in a single operation, which significantly improves installation speed and efficiency, especially in collapsing or unstable ground conditions.
Can the length of the anchor bolts be customized?
Yes, by using couplers, hollow bars can be connected and extended to any required depth according to the project design requirements.
In which soil conditions are TC (Tungsten Carbide) bits recommended?
TC bits are specifically recommended for soft to medium rock formations where standard steel bits may wear down too quickly.
What is the role of the hollow center in the bar?
The hollow center allows for the flushing of air or water during drilling to remove cuttings and subsequently acts as a channel for high-pressure grout injection.
How do I choose between SSR32 and SER32 couplers?
The choice depends on whether your project requires a sealing structure. SSR32 comes with a sealing structure, while SER32 does not. Consult your engineering specs for the appropriate choice.
What applications are best suited for these anchor systems?
They are ideal for tunneling, slope stabilization, foundation reinforcement, and mining projects, particularly where space is narrow or the geology is complex.
KAT DRILLING
