Self drilling anchor bolt system is mainly used for tunnel and underground engineering, slope engineering, ground and foundation engineering. It can be used for pre-construction support and can effextively enhance the stability of soil and rock mass.
The Self-Drilling bolt is a fully threaded hollow bar that initially serves as a drill rod, utilizing a lost bit. The thread is made to comply to ISO 10208. For use in unconsolidated ground or other difficult ground conditions.
The self-drilling hollow bar anchor system is 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 for their requirement and completely covers the entire bolt Coupler: The couplers can be used to join hollow bars and extend the bolt length, it means the anchor can be elongated with the couplers Plate and Nut: The plate and nut are installed according to their design requirement Drill Bit: The drill bit would be selected at the choice of ground condition
• Excellent for spiling (fore-poling)
• Bolt is drilled in and grout is pumped through the center hole with pumpable resin or cement grouts
• The couplers are designed to exceed the ultimate load of the bar by 20%. The couplers are designed to minimize the loss of drill energy
• Several drill bits are available. Most widely used is the EXX Tungsten carbide chisel bit
• Standard length is 3 m (9 ft -10 ft) - Longer lengths are available: 4 m, 6 m
• Galvanized option under ASTM A123
Application
Self drilling anchor system is mainly used in slope stabilization, tunneling pre-support, foundations with micropiles, it is also widely used in the railway system, metro project etc. It can be installed in sites with weak rocks, loose soil, weathered layer, sand with stone layer and so difficult to create a hole in complex formations. The unconsolidated ground condition favor the self-drilling anchor bolt technique for fast and simple method of installation compared to the traditional method.
R-Thread Hollow anchor Bar |
Size |
Outer Dia.(mm) |
Ultimate Lad(kN) |
Yield Load(kN) |
Weight(kg/m) |
R25N |
25 |
200 |
150 |
2.35 |
R32l |
32 |
210 |
160 |
2.83 |
R32N |
32 |
280 |
230 |
3.50 |
R32S |
32 |
360 |
280 |
4.00 |
R32L |
32 |
210 |
160 |
2.50 |
R32N |
32 |
280 |
230 |
2.95 |
R32S |
32 |
360 |
280 |
3.50 |
R32S1 |
32 |
405 |
320 |
4.00 |
R32L1 |
32 |
250 |
190 |
2.60 |
R32N |
32 |
280 |
230 |
2.83 |
R38N |
38 |
500 |
400 |
5.50 |
R38N |
38 |
500 |
400 |
4.95 |
R38S |
38 |
500 |
450 |
5.90 |
R51L |
51 |
580 |
450 |
6.75 |
R51N |
51 |
800 |
630 |
9.00 |
R51L |
51 |
550 |
450 |
6.20 |
R51L1 |
51 |
660 |
540 |
6.75 |
R51N |
51 |
800 |
630 |
8.20 |
R51S |
51 |
925 |
740 |
9.25 |
T-Thread Hollow anchor Bar |
T30L |
30 |
220 |
180 |
2.90 |
T30N |
30 |
260 |
220 |
3.35 |
T30S |
30 |
320 |
260 |
3.60 |
T30S |
30 |
320 |
260 |
3.35 |
T40N |
40 |
539 |
430 |
6.20 |
T40S |
40 |
660 |
525 |
7.20 |
T40N |
40 |
539 |
430 |
5.70 |
T40S |
40 |
660 |
525 |
6.80 |
T52N |
52 |
929 |
730 |
10.20 |
T52N |
52 |
929 |
730 |
9.70 |