Benefits & Features
The split-type friction bolt is a new type of full-length bolt used for securing and activating surrounding rock. Its three-dimensional portion consists of a braided, longitudinally slotted high-strength steel tube. When installed at a bend slightly smaller than the tube diameter, it immediately applies tensile force along its entire length to the borehole wall, simultaneously generating tension to prevent rock uplift. Combined with the support provided by the bolt holder, this creates a three-dimensional stress state in the surrounding rock, thereby stabilizing the formation. The anchoring force increases significantly during rock mass seismic events such as blasting or impact. Even during gradual seismic events in the surrounding rock, the bolt provides support.
Working Principle:
When the split-type friction bolt is installed in a longitudinal position slightly smaller than the tube diameter, it applies a gap force to the surrounding rock along the entire height of the borehole wall; generates tension to prevent rock slippage; and provides support.
Technical Features:
1. Made of high-strength alloy strip;
2. Easy installation;
3. Strong interaction force between the rock column and the rock mass;
4. High shear and tensile strength;
5. Equipped with high-strength support plates to evenly distribute the load;
6. The tunnel height must be greater than the length of the rock tunnel.
Technical Requirements:
1. The surface of the excavated rock tunnel must be smooth, free from severe scratches and corrosion. Welds must be free from defects such as cracks, porosity, slag inclusions, and pipe burnt areas. The tower must be able to move freely on the tower column. The retaining ring interface and the pipe joint opening must be staggered by 170° to 190°.
2. The weld pull-out strength of the retaining ring must be ≥80kN, the ultimate tensile strength of the mast must be ≥110kN, the final fixing force must be ≥25kN/m, and the bearing capacity must be ≥65kN.
Technical Specifications
1. Final Anchoring Force: 3-7 tons;
2. Retaining Ring Pull-out Load: 8-10 tons;
3. Rock Column Tensile Strength: 12-13 tons;
4. Corrosion resistance is 20-30% higher than A3 steel, which is beneficial for long-term use.
Installation Instructions
1. Use compressed air to blow away rock powder from the hole.
2. Install the support plate onto the rod and use an impact drill to drive the bolts into the hole.
Recommended Calculation Method for the Diameter of the Split-Type Anchor Bolt Guide Tube:
Rock Layer: Diameter = (0.9-0.95) × Connecting Rod Diameter
Rock Layer Channel Length: Rock Layer Channel Length + 100mm (Deviation Percentage <1%)
Coal Seam: Diameter = (0.9-1.00) × Rod Diameter
Rock Layer Channel Length: Rock Layer Channel Length + 200mm (Deviation Percentage <1.5%)
