Pipe joint anchor rod
Overview of Pipe Joint Anchor Rods
Pipe joint anchor rod is a new type of anchor rod that is fully anchored and actively strengthens the surrounding rock. Its three-dimensional part is a high-strength steel pipe with longitudinal joints. When installed in a borehole slightly smaller than the pipe diameter, it can immediately apply radial pressure to the hole wall and prevent the sliding of the surrounding rock within the full length range. In addition, the support force of the anchor rod tray support plate can make the surrounding rock in a three-dimensional stress state and achieve the greatness of the rock layer. Under conditions such as blasting vibration and surrounding rock anchoring, the anchoring force increases significantly in the later stage. When the surrounding rock undergoes significant displacement, the anchor rod does not lose its support resistance and has better characteristics than the expansion shell anchor rod.
Specification of pipe joint anchor rod
1. Outer diameter (millimeters): Φ 30, Φ 33, Φ 40, Φ 43 (± 0.5);
2. Length (millimeters): 1200, 1500, 1800, 2000, 2500
3. Material: Q235, 16Mn, 20 Mnsi.
Working principle of pipe joint anchor rod
Install the pipe joint anchor rod in a borehole smaller than the pipe diameter. At this time, three forces will be applied to the surrounding rock: one is the radial pressure on the hole wall within the full length of the pipe joint anchor rod, one is the friction force to prevent the surrounding rock from sliding, and the other is the support force of the pipe joint anchor rod tray support plate. These three forces make the surrounding rock more stable.
Technical characteristics of pipe joint anchor rod
l. High strength alloy strip steel is used as the raw material;
2. The simplest installation;
3. No anchoring agent required;
4. The frictional force between anchor rods and rock mass is high;
5. Has high shear and tensile strength;
6. Equipped with high-strength trays, the trays are evenly stressed;
7. The height of the roadway is greater than the length of the anchor rod.
Technical requirements for pipe joint anchor rods
1. The surface of the joint pipe anchor rod should be flat, without serious tensile damage or rust. The weld should be free of cracks, pores, and slag inclusions, and burning through the pipe wall is not allowed. The tray should be able to move freely on the pole body. It is advisable to misalign the retaining ring interface with the pipe seam opening by 170o to 190o.
2. The pull-out force of the retaining ring weld seam is ≥ 80kN, the ultimate tensile strength of the rod is ≥ 110kN, the initial anchoring force is ≥ 25kN/m, and the bearing capacity of the tray is ≥ 65kN
Technical performance of pipe joint anchor rod
1. Initial anchoring force: 3-7 tons;
2. Pipe ring detachment load: 8-10 tons;
3. Anchor rod pipe tensile strength: 12-13 tons;
4. The corrosion resistance is 20-30% higher than A3 steel, which is beneficial for long-term use.
Method of using pipe joint anchor rods
1. Determine the anchor bolt hole position according to design requirements and drill holes using drilling tools.
2. Blow out the rock powder inside the hole with compressed air.
3. Install an anchor plate on the rod and use an impact drill to drive the anchor rod into the hole.