A prestressed full-length anchor hollow grouted anchor with auxetic effect

Abstract

A prestressed full-length anchoring hollow grouting anchor rod with auxetic effect, the inside of the rod body is provided with a central grouting hole through the axial direction; the rod body is composed of a threaded section at the end and a main body section outside the threaded section; the threaded The outside of the section is provided with external threads; the surface of the main body section is uniformly fixedly connected with a plurality of protruding rib rings along the length direction, and a connecting part is formed between adjacent protruding rib rings; the outer diameter of the protruding rib rings is smaller than that to be The diameter of the construction drilling hole; each connecting part is provided with a plurality of axial flat holes and a plurality of circumferential flat holes connected with the central grouting hole; Fitted and connected on the outside of the threaded section, and closer to the end of the rod body than the tray; the centering ring is set outside the main body section; the outer diameter of the centering ring is adapted to the diameter of the drilled hole to be constructed. The anchor rod has an auxetic effect, can apply a large prestress, and is beneficial to realize full-length anchoring.

Description

technical field [0001] The invention belongs to the technical field of engineering support, in particular to a prestressed full-length anchoring hollow grouting anchor rod with auxetic effect. Background technique [0002] Because the bolt support can effectively mobilize the self-bearing capacity of the surrounding rock, it can not only support the surrounding rock, but also modify and strengthen the surrounding rock. Therefore, it has been widely used since its birth. It is used in the support of mines, tunnels, slopes, water conservancy and other projects. At present, the widely used bolt support methods can be mainly divided into two categories. One is the first-filled and then-anchored anchor represented by solid threaded steel anchors and resin coils. It has the advantages of high strength and timely support, but because the curing effect of the resin drug coil used is related to whether the stirring and mixing are sufficient, the quality of resin curing is difficult ...

AI Technical Summary

Problems solved by technology

This anchoring method is not suitable for formations that require rapid support because the cement mortar has been consolidated for too long and cannot quickly form anchoring force.

In addition, due to the good fluidity of cement slurry, slurry leakage often occurs in broken formations. When grouting upward holes, it is necessary to install multiple supporting devices such as grout stoppers and exhaust pipes. Therefore, the use of such bolts The structure is complex, the construction process is many, and the quality of grouting is not easy to guarantee

[0004] In addition, the above two anchoring methods are anchored through the bonding force between the thread on the surface of the rod body and the anchoring body, and the anchoring force is positively related to the normal stress on the contact surface of the anchor rod-anchor agent. Under the action of axial tension, the section of the rod body will shrink to varying degrees, thereby reducing the normal stress acting on the contact surface of the anchor rod-anchor agent, and finally affecting the shear strength between the anchor rod and the anchoring body

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