Installation and procedures

A fully resin grouted bolting system includes simply a two-part resin-catalyst capsule and a steel bar with a plate and nut. The installation procedure of this system is shown as follows:

Step 1 Drilling hole

Drill hole to correct diameter and length for bolt to be used (Figure 18a. The ideal hole length should be 50-60 mm shorter than the bolt.

Step 2 Capsule installation

Install the pre-determined number of capsules to fully grout the bolt in the borehole, as shown in Figure 18b.

Step 3 Rotation of capsule

Connect the bolt the spinning device. Forcibly spin the bolt into the hole at the same time rotating for the manufacturer’s recommended time at high rpm throughout the netire length of the capsule as shown in Figure 18c. When the bolt reaches the back of the hole, it should be spun a further 2-4 seconds to ensure complete mixing. This leads to shredding of the capsules and mixing the resin and catalyst. It is essential that the bolt is pushed and spun to the back of the hole before mixing is finished.

Step 4 Hold bolt

Hold bolt in place until resin hardens sufficiently to hold the bolt in the hold. Retract the spinning device.

Step 5

Attach washer and nut, if not attached during installation. In most modern bolting systems the plate and washer are added before installation.

Pretensioned rock bolts require the bolt to be tightened to a predetermined level. A torque-limiting device allowing the nut to tighten up the bolt at a predetermined load is hence applied. These devices consist of shear pins, chemdrive nuts, nuts with crimped inserts and modified thread sections. Once the resin has reached a sufficient strength, the nut is spun until breaking the torque-limiting device and move up the thread, imparting tension into the bolt via the threaded section.

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