What is Anchor Rock Bolt
Anchor rock bolt are solid or hollow steel rock bolts that are drilled into rock mass during excavation of the surrounding rock to avoid loose collapse of rock mass, which serves to reinforce and connect the soil body as a whole. The mortar or other materials are used to consolidate between rocks and set with steel backing plates
Rock Bolt Install Tips
- Rock bolt construction should be carried out after initial shotcrete, anchor rock bolt is driven into the hole with special machinery, and a special impactor should be equipped when using a general air-powered rock drill. The drill hole should be round and straight, and in line with the surrounding rock wall or rock layer where it is located. The main structural plane is in vertical direction.
Lay the position according to design requirements, the allowable deviation of hole position is not more than 10cm, and the insertion length of rock bolt body should not be shorter than 95% of design length.
When rock bolt body – high strength rebar is inserted into anchor hole, the position should be kept in the middle and insertion depth should meet design requirements.
- The mortar filled in the mortar anchor hole should be full and dense, and appropriate amount of micro-expansive agent and quick-setting agent can be added to the mortar or cement slurry.
- After anchor rod is installed and mortar filled is finally set, pallet should be installed immediately and nut should be tightened.
Common problems on Rock Bolt Worksite
- The number and length of anchor rock bolts are lower than the design value, and the distance between anchor bolts is large. The U-shaped welding is not adopted between the lock bolt and the steel frame. The on-site inspection shall separate the advanced small catheter, advanced anchor rod, hollow anchor rod, and lock foot anchor pipe (rod) in detail.
- The raw material of anchor rock bolt does not meet the standard. Wall thickness and weighing inspection of anchor rod should be checked on site.
The phenomenon that hollow grouting bolt designed is not grouted or replaced with mortar bolts.
- The angle of rock bolt penetration does not meet design requirements.