Application of Anchor Cable Support in Coal Mining(2)

3 Anchor cable support design

3.1 The structure of the anchor cable

As shown in the figure 2, the anchor cable is mainly composed of hairy teeth, retaining bands, steel strands, backing plates and anchors.

1) The burrs are small teeth that are fixed on the steel strand by bolts or spot welding to break and stir the resin roll, and also play a role in positioning the steel strand in the center. The fur teeth are fixed along the steel strand, and the distance between adjacent ones is generally 200-300 mm.

2) The retaining hoop is a cylindrical rubber or plastic with a diameter smaller than the hole diameter fixed on the steel strand. Its main function is to prevent the gelatinous resin from flowing out during the process of stirring the resin and pushing the steel strand.

3) The steel strand is the main body of the anchor cable structure, which is composed of multiple thinner steel wires. The length varies according to the depth of the hole, generally 0.5 m longer than the depth of the hole, and the total length is usually 5-8 m.

4) The backing plate and anchor are the final stressed components installed at the end of the anchor cable. The backing plate is generally composed of channel steel and anchor rod discs.

3.2 Anchor cable support parameters

The anchor cable support shall be designed and calculated according to the suspension action to ensure that the anchor cable can bear the quality of the potential falling rock formation.

1) The quality of potential falling rock formations per unit length of the roadway

2) The fall length that a single anchor cable can bear

3) Anchorage length

4) Total length of anchor cable

4 Anchor cable installation process

The process flow of anchor cable installation is shown in Figure 3.

1) Positioning refers to controlling the drilling mechanism to the position that needs to be drilled to ensure that the actual installation of the anchor cable device is consistent with the design.

2) When drilling, according to the designed hole position, use a bolt drill to drill holes of preset depth and angle, of which 45. Holes below the corners need to be purged after drilling.

3) Put the resin roll into the hole, the resin rolls with different solidification speeds are fed in in order (as shown in Figure 4), and the sleeve self-locking device is used to feed the resin roll.

4) The anchor cable installation is shown in Figure 4. Push the anchor cable slowly to make the anchor cable bear the resin roll to the bottom of the hole.

5) Fix the tail of the anchor cable on the Anchor Bolt rig, one person holds the anchor cable steady, and the other starts the drilling rig. At first, the mixing should be slow, and then gradually increase the mixing speed. The whole process should be controlled between 20-30 s; the mixing advances There can be no pause during the mixing process. After the mixing is completed, the anchor cable needs to be stabilized and waited for about 30 s to ensure the initial setting of the anchoring agent, and then the mixing system is removed.

6) After the stirring is completed, it is generally necessary to wait for 30 minutes for the anchoring agent to fully solidify, and the waiting time can be extended if conditions permit.

7) As shown in Figure 5, install and connect the tensioning tool and the anchor cable, and slowly pressurize the anchor cable to tension. When the designed stress value is reached, stop the pressurization and move the reversing valve to return the cylinder to the cylinder. , Lock the anchor, remove the tensioning machine, and now, the tensioning is complete.

8) After the anchor cable tension is completed, the redundant anchor cable needs to be removed, and the special anchor cable cutter and the manual oil pump are used to cooperate with the manual oil pump to perform the anchor cable cutting operation. The installed anchor cable is shown in Figure 6.

5 Conclusion

1) Cable-anchor support has the advantages of fast construction speed, high load-bearing capacity, strong adaptability to surrounding rock, and reliable engineering quality; cable-anchor support should be designed according to the actual situation of the roadway site and installed in strict accordance with the cable-anchor installation process. .

2) Anchor rope support is easy to match with support methods such as bolts and metal nets, and complements the shortcomings. This is of great significance for reducing support costs, increasing benefits, and improving support reliability.