Anchor Bolt Fabrication
Raw materials qualified, processed anchor bolts meet requirements;
Rod body diameter uniform, no severe corrosion or bending.
Measurement and Positioning
Determine anchor bolt hole positions according to design requirements and mark them; allowable deviation of hole position is ±150mm.
Anchor Bolt Drilling
Before drilling, inspect surrounding rock for falling blocks or cracks to ensure safety;
Drilling should be perpendicular to the rock surface or the main structural plane at the location;
Depth error of drilling shall not exceed ±50mm. The hole should be round and straight, with diameter 15mm larger than the rod diameter.
Hole Cleaning and Inspection
After drilling, clean the hole with high-pressure air, check whether the spacing, depth, and angle of anchor bolt holes meet requirements; depth error shall not exceed ±50mm. Unqualified holes shall be abandoned and re-drilled.
Grouting and Installation
Mortar strength shall not be less than M20;
Insert the grouting pipe to 5-10cm from the hole bottom, continuously inject mortar to the hole bottom using high-pressure air, slowly withdraw the grouting pipe while keeping the pipe outlet buried in mortar. After fully withdrawing the grouting pipe, immediately insert the anchor bolt into the hole, then plug the hole with a wooden wedge to prevent mortar loss;
Installed anchor bolts shall not be struck or used to hang heavy objects;
The grouting nozzle shall not be pointed at people.
Anchor Bolt Acceptance
If no cement slurry flows out from the hole when the anchor bolt reaches the bottom, the anchor bolt must be pulled out and re-grouted and reinstalled;
The length of the rod inserted into the hole shall not be less than 95% of the design requirement, and the installation quantity shall meet the design requirements;
The anchor bolt bearing plate shall be in close contact with the shotcrete surface.