Ground Foundation Engineering Self Drilling Anchor Bar System Drilling Bit

• Customization: Available
• After-sales Service: Available
• Warranty: Available
• Model NO.: R32S
• Certification: CE, RoHS, ISO 9001:2000
• Standard: AISI, GB, ASTM
• Surface Treatment: Galvanized
• Manufacturing Process: Forging
• Material: Cast Steel
• Application: Deep Foundation Use
• Field: Coal Mining
• Type: Carbon Steel Bar
• Processing Service: Cutting
• Size: R25/R32/R38/R51/T30/T40/T52/T76/T108/T111/T130...
• Finished: Galvanized,Epoxy
• Usage: Mine,Tunnel,Slope,Foundation Pit
• Transport Package: Carton Box
• Specification: customised
• Origin: China
• HS Code: 73082000
• Production Capacity: 100, 000 Ton Per Year

Product Description

A self-drilling anchor is a type of bolt used to ensure the stability of the roof and walls in underground mining and tunnel construction. Unlike other types of bolts, self-drilling bolts do not require pre-drilling and can drill and hold at the same time.

These bolts are designed with a hollow threaded bar with a one-time use drill bit at its end, simplifying and reducing the installation process.

Once installed, they are filled with resin or cement mortar to consolidate the ground. In addition, these bolts can be joined by couplings to achieve lengths that would be impossible with other types of bolts.

At the end of the bolt, there is a nut that, once installed, is tightened, putting the bearing plate and the bolt itself under load, further increasing the bolt's effectiveness.

Self-drilling anchors can also be used in areas where the rock is harder or more compact, using different types of bits. By drilling and securing at the same time, the need for additional equipment for pre-drilling is reduced, which also reduces cost and installation time.
 

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.
 

Advantages of self-drilling bolt

1. Suitable for all kinds of geotechnical conditions. SDA bolt has a better construction effect than those of common anchor bars, especially is used in complex geological conditions, such as easy-to-collapse geology.

2. Unlimited drilling depth. Due to the limitations of existing rock bolt materials and drilling equipment, the conventional rock bolt has a relatively shallow drilling depth, but the self-drilling rock bolt can drill deeper due to its small drilling resistance.

3. Suitable for construction in narrow spaces. The length of the single bolt can be cut or extended as required. Common specifications are 2m, 3m, 4m, and 6m.

4. Simple construction process. The self-drilling bolt can complete the drilling, grouting, and anchoring in one drilling, simplify the technological process and accelerate the construction speed.

5. It helps stabilize the hole wall. When drilling, the screw grouting machine is used to supply cement grout with a water-cement ratio of 0.4~0.5 under pressure, so that the grout can quickly fill the borehole and the rock and soil mass, and be absorbed and solidified by the hole wall to ensure the stability.

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