Self-Drilling Hollow Self Drilling Rod Mining Rock Anchor Bolt

Short Description:

The self-drilling Hollow bar anchor system is comprised of a hollow threaded bar with an attached drill bit that can perform drilling, anchoring and grouting in a single operation. The hollow bar allows air and water to freely pass through the bar during drilling to remove debris and then allow grout to be injected immediately after drilling is completed. Grout fills the hollow bar and completely covers the entire bolt. Couplers can be used to join hollow bars and extend the bolt length while nuts and plates are used to provide the required tension.

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Product Introduction

Self-drilling anchors are a special type of rod anchor. Self-drilling anchors consist of sacrificial bits, hollow steel bars of appropriate outer and inner diameters, and connecting nuts.

The anchor body is made of hollow steel pipe with external thread. The steel tube has a sacrificial bit at one end and the corresponding nut has a steel end plate.

Self-drilling anchors are used in such a way that a hollow rebar (rod) has a corresponding sacrificial bit on top of it instead of a conventional bit.

The centering device ensures consistent grout coverage around the hollow rebar and that the rebar remains centered in the drilled hole.

Anchoring hollow bars are produced in profiles with standard lengths of 2.0, 3.0 or 4.0 m. The standard outer diameter of hollow steel bars ranges from 30.0 mm to 127.0 mm.

If necessary, hollow steel bars are connected with connecting nuts. Depending on the type of soil or rock mass, different types of sacrificial bits are used. Hollow bars are superior to solid bars with the same cross-sectional area because of their better structural properties in terms of buckling, perimeter (bonded area), and bending stiffness. The result is higher buckling and bending stability for the same amount of steel (material cost).

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Application

Application scope and advantages of self-drilling anchors
The basic application of self-drilling anchors is to install in soil/rock conditions, such as during conventional anchor installation, there is a risk of borehole collapse due to the pull-out of the drill bit.
The installation length of self-drilling anchors can be larger than traditional rod anchors (connecting hollow steel bars with connecting nuts).

Application range:
Micro piles for foundation underpinning (larger diameter anchors).

Anti-pull anchors:
Anchors for protecting rock slopes and building foundation pits.
Anchors for soil slope stabilization (soil nails).
Anchors for stabilizing embankments.
Anchors to protect retaining structures.
Drain (drain).

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Speicifications of Self Drilling Rock Bolt

Size	Outer Dia. (mm)	Inner Dia. (mm)	Ultimate Load (KN)	Yiedl Load (KN)	Weight (kg/m)
R25	25	14	200	150	2.35
R32L/20	32	21.5	210	160	2.7-2.83
R32N/17	32	18.5	280	230	3.5
R32S/15	32	15	360	280	4.1
R38N/20	38	19	500	400	6
R51/34	51	34	580	450	6.95
R51/29	51	29	800	630	9

Anchor Bolt

Anchor bolt means a rod that transfers the structures or geotechnical load to a stable rock formations, it consistsof rod, drill bit,coupling, plate, grouting stopper and nut. It has been widely used in tunnling, mining,slope stabilization, tunneldiseasestreatment and roof supporting of undergroundworks. It is for loose ground(clay, sand friable etc.) Hollow anchor rod is made of seamless tube with high strength.

Product Details

Features of Hollow Grouting Anchor Bolt

Hollow design, implement the grouting tube function, avoid the mortar loss when the traditional grouting tube pulled out.Grouting full, and can achieve the pressure grouting to improve project quality.

Center is good, mortor can wrap the bolt body together, so that it can avoid corrosion to achibe along term supporting purposes.

Easy installation, without onsite processing of threads. It can be easily installed an plate, nut.