Hollow Grouted Rock Bolt

 

Hollow grouted rock bolt installation process and precautions

First, along the excavation contour of the arch, the position of the anchor rod is marked according to the design spacing.

Connect the bolt, ensure that the drill and the hole in the bolt are not blocked by foreign matter, and then install the drill on one end of the bolt, and connect the other end with the rock drill (TY28 wind gun).

The drill bit of the anchor bolt is aligned with the drilling position marked on the face of the palm, and the drilling begins after the water supply and wind supply. Follow the principle of more rotation and less impact, so as not to block the water hole by drilling ballast.

After drilling to the design depth, clean the hole with water or high pressure air, and remove the drill pipe connecting sleeve after confirming that it is smooth, and keep the exposed length of the anchor rod 10 ~ 15cm.

Drive the hole cap (stop plug) into the hole about 30cm using the hole cap fitting.

If it is necessary to extend the bolt, connect the driven bolt with the waiting bolt with the bolt connecting sleeve and continue drilling to the design depth.

 

 

Before grouting, check whether the state of the grouting pump, accessories and pulping raw materials are complete and qualified. Using No. 425 ordinary Portland cement, the water-cement ratio is 1:1, the grouting pressure is 0.5 ~ 1.0MPa, and the initial setting time is 1 ~ 2min.

Quickly connect the bolt, grouting pipe and the quick joint of the grouting pump, and start the grouting pump until it overflows from the orifice or reaches the design pressure. Each bolt needs to be done in one go.

After the completion of a bolt, quickly remove the grouting hose and bolt joint for cleaning, and move to the next bolt for use. If the pump stops for a long time, it is necessary to discharge the residual mortar in the grouting pipe.

 

 

Keep the distance between the drilling rig and the palm surface to prevent the surrounding rock from sliding.

Ensure that the bolt and drill water holes are unblocked. If signs of blockage are found, pull back 50cm and repeatedly sweep the holes until the design depth is reached.

With water slurry, avoid condensation in the grouting pipe and pump.

If the pipe is blocked, clean the anchor rod, grouting hose and grouting pump in time; If there is pressure on the pressure gauge, remove the pressure first and then remove the joint.

Quick-setting cement seals the hole outside the stop plug to ensure that the slurry does not escape at 1.0MPa pressure.

 

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