Surrounding rock support method adopting tensioning type pre-tightening anchor rod

Abstract

The invention discloses a surrounding rock support method adopting a tensioning type pre-tightening anchor rod. The method comprises the steps as follows: a tensioning machine is adopted to tension the anchor rod (1) and apply pre-tightening force to the anchor rod (1), and the anchor rod is locked by anchor rod locks such as an anchor rod support plate (4), an anchor ring (3) and a clamping piece (2). The method is applicable to the support way of reinforcing the surrounding rock of a roadway by mounting of various specifications of anchor rods with pre-tightening force, the used anchor rod is directly cut out from a reinforcing steel bar according to a required length, and the processing and manufacturing process of the anchor rod is simple; after the anchor rod stirs an anchoring agent (5), an anchor rod tray and the anchor rod locks can be directly pushed to the surrounding rock surface along the anchor rod, an anchor drilling machine can be withdrawn after the anchoring agent is solidified, and rapid mounting is realized while a top plate is protected in time; the conditions of insufficient anchor rod torque force due to human factors and torsion failure of the anchor rod due to overlarge torque force can be avoided, and the labor intensity of a construction worker can be reduced simultaneously; and besides, the pre-tightening force can be recovered by tensioning the faulty anchor rod again, the anchor rod cost can be reduced, and the anchor rod locks can be recovered and recycled.

Description

technical field [0001] The invention relates to a rock bolt surrounding rock support method, in particular to a tension-type pre-tightening anchor bolt surrounding rock support method suitable for geotechnical engineering, coal mine underground, tunnel engineering, etc. Surrounding rock support technical field. Background technique [0002] Bolt support is a reinforcement and support method used in surface engineering such as slopes, deep foundation pits of rock and soil, and underground chambers such as tunnels and stopes. It is made of metal parts, wood parts, polymer parts or other materials. Make poles, drive them into the pre-drilled holes in the surface rock mass or the rock mass around the chamber, use the special structure of the head, the pole body and the tail support plate, or rely on the bonding effect to combine the surrounding rock with the stable rock mass Together, they can produce suspension effects, composite beam effects, and reinforcement effects to achi...

AI Technical Summary

Problems solved by technology

[0005] 1. Increasing the pre-tightening force of the bolt is mainly controlled by the torque of the nut, that is, the outer thread of the rolling section is set at the end of the bolt, and the applied pre-tightening force is calculated from the torque applied to the nut by a torque wrench or a rock bolt rig. The higher the torque The larger the pre-tightening force of the large anchor, but it is difficult for construction tools to meet the requirements when the nut torque of more than 300Nm is applied to the anchor. To obtain a larger torque of more than 300Nm mainly depends on manpower, so the labor intensity of the construction personnel is high, and due to It is difficult to ensure that the nut torque of each anchor rod can meet the requirements due to the difference in the physical fitness of the construction personnel and the length of operation time. In actual construction, the design pre-tightening force is mainly guaranteed by management means, and the pre-tightening force is closely related to the nut torque. The corresponding relationship of torque is different due to the different materials and construction methods of anchor rods and nuts. For different installation conditions, the same torque may have different pre-tightening forces, and the pre-tightening forces are variable and uncontrollable;

[0006] 2. The relationship between bolt torque and preload is shown in the table (taking the test data of a left-handed bolt with a yield strength of 335MPa as an example), it can be seen from the table that when the bolt reaches the maximum torque, the average anchor preload reaches 81KN About 62% of the yield strength of the anchor material is only reached, and the role of the anchor material is not fully utilized, which actually causes waste;

[0008] 3. In addition, it is difficult to detect the pre-tightening force of the anchor rod with nuts. Since the relationship between the pre-tightening force and the nut torque is different due to different materials and construction methods, other auxiliary means must be used to detect the pre-tightening force. The results are obtained, so the operation is complicated, and when the torque is too large and exceeds the set value, it will also cause damage to the rod body of the anchor;

[0009] 4. Due to the humidity in the underground, the nuts fastening the bolts are easy to rust. When the nuts and the tails of the bolts are corroded, it is very difficult to fasten or disassemble them. It is easier to damage the anchor rod. After the thread is rusted, the anchor rod will be scrapped and cannot be used again

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