Prestressed expansion shell anchor and construction method thereof

Abstract

The present invention discloses a prestressed expansion shell anchor rod, comprising an expansion shell and an expansion shell inner wedge and an anchor rod arranged at both ends of the expansion shell, wherein the expansion shell comprises an expansion shell connection part and an expansion shell sheet, and the expansion shell sheet is circumferentially arranged on the expansion shell connection part; the expansion shell inner wedge is in sliding contact with the top of the expansion shell; the anchor rod comprises an anchor rod body, one end of the anchor rod body is fixedly installed with a screw rod through a connecting sleeve, the screw rod and the expansion shell inner wedge are connected through threaded transmission, and the top of the connecting sleeve is in extrusion contact with the bottom of the expansion shell; the anchor rod is rotated to drive the expansion shell inner wedge to move into the expansion shell to push the expansion shell sheet to deform outward until the expansion shell connection part breaks, and finally the expansion shell sheet expands to the hole wall to apply prestress to the rock mass; and a construction method of the prestressed expansion shell anchor rod is also provided. The present invention has the advantages of low cost, good anchoring performance, and easy mechanization and automation.

Description

Technical Field

[0001] The invention relates to the technical field of geotechnical engineering anchoring and supporting, and in particular to a prestressed expansion shell anchor rod and a construction method thereof. Background Art

[0002] During the construction of underground projects, mine tunnels, railway tunnels, slope protection and military projects, in order to prevent the ground from deformation, collapse and instability, it is necessary to reinforce the ground. The main measure adopted is to bury mortar anchors or anchors with expansion heads in the ground, and use the tension of the anchors and the concrete grouting body integrated with the anchors to form an integral reinforcement structure for the ground, so as to achieve the purpose of controlling deformation.

[0003] Compared with ordinary mortar anchors, prestressed anchors have the following advantages: 1. By applying prestress to the rock mass between the inner and outer anchor heads, a rock compression zone will be formed; 2) Prestressed anchors are installed continuously in the rock mass, and the overlapping and intersecting compression zones will form a compression bearing layer with a certain thickness; 3) Especially in tunnel engineering, the compression zone formed by the prestressed anchor can form a bearing arch of the rock mass. Under the action of the arch effect, it not only fully mobilizes the self-bearing capacity of the surrounding rock, but also greatly improves the resistance of the surrounding rock outside the arch. Prestressed anchors include fast medicine rolls, expansion shell anchors and other types. Among them, the expansion shell anchor is usually composed of basic components such as the expansion shell, rod body, pad, nut, etc., and other components such as ball pads, grouting pipes, exhaust pipes, grouting plugs, centering devices, etc. are added when necessary. It is a kind of prestressed mechanical anchoring anchor.

[0004] Compared with anchor rods such as quick-roll anchor rods, when the drilling depth and rod length are the same, the rock compression zone formed by the shell expansion anchor rod is larger and can provide better anchoring effect. At the same time, because there is no need to wait for the anchor body to solidify, the instant prestress provided by the shell expansion anchor rod is also more advantageous. For example, the invention patent with application number CN201510711711.4 discloses a grouting anchor rod, including a coaxially arranged anchor rod body, a wedge and a drill bit, one end of the wedge is inserted into the anchor rod body, and the other end is connected to the drill bit; a grouting channel is passed through the anchor rod body, the wedge and the drill bit; when the anchor rod body rotates in the same direction as the drill bit cutting, the relative position of the anchor rod body, the wedge and the drill bit is fixed, and the anchor rod body drives the wedge and the drill bit to rotate synchronously. At the same time, the use method of the grouting anchor rod is also disclosed, including five steps of drilling, anchoring, pre-tightening, sealing and grouting. This patent has comprehensive functions and can continuously complete drilling, anchoring and grouting in one construction. However, there are still problems: complex structure, high production cost, the anchor body and the rod tail nut are set through, relying on manual operation, and it is not easy to realize mechanized operation. After construction, the anchor body and other components are exposed outside the rock body, and need to be cut due to process requirements, safety and other factors, thereby increasing construction costs and reducing construction efficiency. Summary of the invention

[0005] In order to overcome the deficiencies of the prior art, the purpose of the present invention is to provide a prestressed shell expansion anchor rod with low production cost, good anchoring performance and easy mechanization and automation operation, and to introduce a construction method of the prestressed shell expansion anchor rod.

[0006] The purpose of the present invention is achieved by the following technical solutions:

[0007] A prestressed expansion shell anchor rod comprises an expansion shell and an expansion shell inner wedge arranged at both ends of the expansion shell, and an anchor rod, the expansion shell comprises an expansion shell connecting part and an expansion shell sheet, the expansion shell sheet is circumferentially arranged on the expansion shell connecting part; the expansion shell inner wedge is in sliding contact with the top of the expansion shell; the anchor rod comprises an anchor rod body, one end of the anchor rod body is fixedly mounted with a screw rod through a connecting sleeve, the screw rod and the expansion shell inner wedge are connected by threaded transmission, and the top of the connecting sleeve is in extrusion contact with the bottom of the expansion shell; the anchor rod is rotated to drive the expansion shell inner wedge to gradually move into the expansion shell, pushing the expansion shell sheet to deform outward until the expansion shell connecting part breaks, so that the expansion shell sheet expands to the hole wall to apply prestress to the rock mass.

[0008] Furthermore, the shell expansion connection part and the shell expansion sheet are integrally formed, and the inner side of the shell expansion sheet is provided with an inner conical surface and an inner annular surface. The inner side of the bottom end of the shell expansion connection part is provided with an extrusion surface adapted to the top of the connecting sleeve, and gaps are provided between adjacent shell expansion sheets; preferably, the extrusion surface is an annular inclined surface.

[0009] Furthermore, the shell expansion connection part and the shell expansion sheet are split structures, the inner side of the shell expansion sheet is provided with inner conical surface and inner annular surface, the inner side of the bottom end of the shell expansion sheet is provided with an extrusion surface adapted to the top of the connecting sleeve, and a notch is provided on the shell expansion connection part; preferably, the extrusion surface is an annular inclined surface.

[0010] Furthermore, the outer side of the expansion piece has continuously arranged serrations.

[0011] Furthermore, a pad and a driving nut are configured at the end of the anchor rod body, and the two ends of the anchor rod body are fixedly installed with the driving nut and the connecting sleeve respectively, and the driving nut is rotated to rotate the anchor rod body and squeeze the expansion shell connection part through the connecting sleeve; preferably, the driving nut is configured as a blind nut.

[0012] Furthermore, an independent extrusion head is arranged on the top of the connecting sleeve.

[0013] Furthermore, the anchor rod body is configured as a hollow anchor rod, and a slurry outlet hole is provided on the connecting sleeve.

[0014] Furthermore, an anti-vibration box is arranged between the driving nut and the backing plate, and a pressure-releasing assembly is arranged at the end of the anchor rod body.

[0015] The present invention also provides a construction method based on the prestressed expansion shell anchor rod, comprising the following steps:

[0016] S1 drilling: drilling anchor holes in the rock mass through the drill bit;

[0017] S2 assembly installation: insert the pre-assembled expansion shell anchor assembly into the anchor hole, so that the pad is close to the rock wall of the anchor hole;

[0018] S3 anchoring: Rotate the drive nut, the anchor rod body rotates to drive the connecting sleeve and the screw rod to rotate, so that the inner wedge of the expansion shell moves to the outside of the anchor hole and pushes the expansion shell to achieve fixation and prestressing on the anchor hole.

[0019] The step S3 includes the following sub-steps:

[0020] S31 Initial stage: Rotate the anchor rod. At the beginning, since the connecting sleeve is always pressed on the bottom surface of the expansion shell, the inner wedge of the expansion shell slides into the expansion shell, pushing the expansion shell sheet to deform outward and close to the hole wall, thus completing the expansion shell fixation;

[0021] S32 intermediate stage: continue to rotate the anchor rod. When the torque exceeds a certain value, the extrusion force of the connecting sleeve exceeds the strength limit of the shell expansion connection part, and the shell expansion connection part breaks to make room for the internal space.

[0022] S33 Ending stage: Continue to rotate the anchor rod, the screw will drive the upper end of the anchor rod body to move upward through the connecting sleeve, so that the anchor rod elastically stretches, and applies axial preload to the inner wedge and the expansion shell. At this time, the axial preload is transmitted to the rock wall of the anchor hole through the anchor rod body, driving nut and pad, completing the application of preload of the expansion shell anchor rod.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] 1. The present invention adopts a unique shell expansion structure with a shell expansion connection portion. Compared with a common shell expansion structure, the shell expansion structure has fewer components and can reduce production costs.

[0025] 2. The shell expansion connection part of the present invention has a first state of connecting the shell expansion pieces, and a second state of expanding the shell expansion pieces to apply prestress to the hole wall rock after breaking. A serrated structure is arranged on the outer side of the shell expansion piece, which effectively increases the contact area between the shell expansion piece and the surrounding rock hole wall after the shell expansion is opened. At the same time, the shell expansion, the wedge inside the shell expansion and the screw rod constitute a stable support structure for the anchor hole, thereby greatly improving the anchoring force of the shell expansion.

[0026] 3. Compared with common expansion shell anchor rods, the present invention not only improves assembly efficiency due to the simple structure of the expansion shell part, but also does not require cutting of the exposed part of the anchor rod body, thereby reducing construction steps. In particular, the driving nut adopts a blind hole nut structure, which is easy to realize continuous, mechanized and automatic operation, and can significantly improve work efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 A three-dimensional diagram of an expansion shell of the prestressed expansion shell anchor rod of the present invention;

[0028] Figure 2 It is a cross-sectional view of the anchoring part of the prestressed expansion shell anchor rod of the present invention;

[0029] Figure 3 A cross-sectional view of the anchoring portion of the prestressed expansion shell anchor rod of the present invention when an extrusion head is provided;

[0030] Figure 4 This is the overall structural diagram of the prestressed expansion shell anchor rod of the present invention;

[0031] Figure 5 This is a structural diagram of the prestressed expansion shell anchor rod of the present invention being configured as a hollow anchor rod body;

[0032] Figure 6 A structural diagram of a seismic box provided for the prestressed expansion shell anchor rod of the present invention;

[0033] Figure 7 This is a structural diagram of a prestressed shell anchor rod provided with a pressure relief assembly according to the present invention;

[0034] Figure 8 A structural diagram of a prestressed expansion shell anchor rod provided with a seismic box and a pressure-releasing assembly according to the present invention;

[0035] Fig. 9 This is a construction state diagram of the prestressed shell expansion anchor rod of the present invention;

[0036] Fig.10 This is a flow chart of the construction of the prestressed shell expansion pressure-relieving earthquake-resistant anchor rod of the present invention;

[0037] Fig.11 A three-dimensional diagram of another expansion shell of the prestressed expansion shell anchor rod of the present invention;

[0038] Fig.12 A three-dimensional diagram of another expansion shell sheet of the prestressed expansion shell anchor rod of the present invention;

[0039] Fig.13 It is a three-dimensional exploded view of another expansion shell of the prestressed expansion shell anchor rod of the present invention;

[0040] The markings and corresponding parts in the figure are: 1-shell expansion piece, 10-shell expansion connection part, 11-annular body, 12-serration, 13-extrusion surface, 14-inner annular surface, 15-inner conical surface, 2-shell expansion connection piece, 21-notch, 3-shell expansion inner wedge, 30-cone, 31-outer conical surface, 4-anchor rod, 40-slurry outlet hole, 41-connecting sleeve, 42-screw rod, 5-extrusion head, 6-anchor rod body, 7-shim plate, 8-drive nut, 80-anti-seismic box, 81-pressure relief assembly, 9-anchor hole. DETAILED DESCRIPTION

[0041] The present invention will be described in more detail below in conjunction with the accompanying drawings. It should be noted that the description of the present invention with reference to the accompanying drawings is only illustrative and not restrictive. The various embodiments can be combined with each other to form other embodiments not shown in the following description.

[0042] The prestressed shell expansion anchor provided by the present invention has a simple structure and reduces costs, while also achieving a good anchoring effect and realizing higher work efficiency through mechanized operation, thereby significantly improving the cost-effectiveness.

[0043] The expansion anchor has the following features: Figure 1 An expansion shell is shown, the expansion shell comprises an integrally formed expansion shell connection part 10 and an expansion shell sheet 1, the expansion shell sheet 1 is arranged in an annular shape on the expansion shell connection part 10, the number of the expansion shell sheets 1 is more than two, each expansion shell sheet 1 has the same shape and is evenly arranged, and a gap is formed between adjacent expansion shell sheets 1, the expansion shell connection part 10 will break from the gap when the external force exceeds its strength limit, so that the expansion shell sheet 1 can expand outward; in this embodiment, the number of the expansion shell sheets 1 is four, so as to effectively increase the contact area with the surrounding rock hole wall and improve the expansion shell anchoring force;

[0044] like Figure 2 As shown, the shell expansion anchor includes an expansion shell and an expansion shell inner wedge 3 and an anchor rod 4 arranged at both ends of the expansion shell. Each component is made of alloy steel, cast iron and other materials. The expansion shell inner wedge 3 is movably embedded in the top of the expansion shell. The anchor rod 4 includes an anchor rod body 6. One end of the anchor rod body 6 is fastened with a screw rod 42 through a connecting sleeve 41. The screw rod 42 is connected to the expansion shell inner wedge 3 through threaded transmission. The top of the connecting sleeve 41 is in extrusion contact with the bottom of the expansion shell.

[0045] The inner wedge 3 of the expansion shell is a conical nut structure, which includes a cone 30, a through hole with an internal thread is arranged in the cone 30, the outer cone surface 31 of the cone 30 is in sliding contact with the inner cone surface 15 of the expansion shell, the inner side of the expansion shell sheet 1 is provided with an inner cone surface 15 and an inner annular surface 14, and the inner side of the bottom end of the expansion shell connecting part 10 is provided with an extrusion surface 13 adapted to the top of the connecting sleeve 41, and the extrusion surface 13 is an annular inclined surface to enhance the extrusion effect, and the outer side of the expansion shell sheet 1 has a continuously arranged sawtooth 12, which can effectively increase the friction between the expansion shell sheet 1 and the hole wall;

[0046] Compared with the existing expansion shell anchor rods, the prestressed expansion shell anchor rod provided by the present invention has fewer expansion shell structural components, simpler design, easy to achieve standardized production, low cost, and convenient assembly. The expansion shell connecting portion 10 has a first state of connecting the expansion shell piece 1, and a second state of expanding the expansion shell piece 1 to apply prestress to the hole wall rock after breaking. The serration structure 12 on the outside of the expansion shell has good adhesion to the hole wall. At the same time, the expansion shell, the inner wedge of the expansion shell and the screw rod constitute a stable support structure for the anchor hole, which not only has stable operation and good reliability, but also greatly improves the anchoring effect of the expansion shell.

[0047] like Figure 3 and Figure 4 As shown, the top of the connecting sleeve 41 may not have an extrusion surface 13, but is provided as an independent extrusion head 5, the top of the extrusion head 5 is in active contact with the extrusion surface 13 of the bottom of the expansion shell and has the advantages of simple structure and low manufacturing cost, and the other end of the anchor rod body 6 is provided with a pad 7 and a driving nut 8 to form a set of prestressed expansion shell anchor rods fixed in the anchor hole 9;

[0048] By rotating the driving nut 8, the anchor rod body 6 rotates to drive the connecting sleeve 41 and the screw 42 to rotate, and the top of the connecting sleeve 41 or the extrusion head 5 presses the bottom of the shell expansion connection part 10, and the screw 42 drives the shell expansion inner wedge 3 to move inwardly of the shell expansion piece 1 and applies a pressing force to the shell expansion piece 1. The shell expansion is deformed under the action of the forces at the upper and lower ends. Continuing to rotate will cause the shell expansion connection part 10 to break due to exceeding the strength limit, so that the shell expansion is more closely attached to the hole wall, realizing the prestressing action on the anchor hole 9 and the rock formation compression effect;

[0049] In this embodiment, the driving nut 8 is set as a blind nut, an external thread is set on the anchor rod body 6, and an internal thread is set on the connecting sleeve 41. The anchor rod body 6, the driving nut 8 and the connecting sleeve 41 are all fastened and installed to form an integrated structure. Under the drive of the blind nut, the inner wedge 3 of the expansion shell and the anchor rod body 6 move in opposite directions, that is, the driving nut 8 is rotated, the inner wedge 3 of the expansion shell moves along the screw 42 into the expansion shell (outside the anchor hole 9), and the anchor rod body 6 moves into the anchor hole 9, ensuring that the anchor rod body 6 is not exposed;

[0050] Furthermore, if Figure 5 As shown, the anchor rod body 6 can be configured as a hollow anchor rod 4, and a grouting hole 40 is provided on the connecting sleeve 41 to facilitate grouting of the anchor rod 4, thereby enhancing the anchoring performance.

[0051] Furthermore, if Figure 6 As shown, an anti-seismic box 80 is provided between the driving nut 8 and the pad 7 to form a prestressed anti-seismic anchor rod, which is suitable for use in projects with anti-seismic requirements, such as earthquake areas, military projects, etc.;

[0052] Furthermore, if Figure 7 As shown, a pressure-yielding assembly 81 is provided at the end of the anchor rod body 6 to form a prestressed pressure-yielding anchor rod;

[0053] Furthermore, if Figure 8 As shown, an anti-seismic box 80 is arranged between the driving nut 8 and the pad 7 of the yield anchor rod, so that the yield anchor rod can be prestressed and anti-seismic, and the scope of application is further expanded.

[0054] like Fig.11 and Fig.13As shown, the expansion shell of the prestressed expansion shell anchor provided by the present invention has another form of a split structure (using an independent expansion shell connector 2), that is, the expansion shell includes an expansion shell connector 2 and an expansion shell sheet 1 annularly embedded in the expansion shell connector 2, the number of the expansion shell sheets 1 is more than two, each expansion shell sheet 1 has the same shape and is evenly arranged, the expansion shell connector 2 is annular and has a plurality of notches 21 for breaking arranged on the upper part;

[0055] Preferably, the number of the notches 21 is more than two, and the notches 21 have the same shape and are symmetrically arranged. The shape of the notches 21 is a U-shape, a V-shape, or other structures.

[0056] like Fig.12 As shown, the inner side of the shell expansion piece 1 has an inner conical surface 15, an inner annular surface 14 and an extrusion surface 13 arranged up and down, wherein the extrusion surface 13 is an annular inclined surface and is arranged on the inner side of the bottom end of the shell expansion piece 1, and the extrusion surface 13 is adapted to the top of the connecting sleeve 41 or the extrusion head 5. The outer side of the shell expansion piece 1 has serrations 12 that are continuously arranged to increase friction, and the bottom of the shell expansion piece 1 is an annular body 11 with an outer annular surface.

[0057] like Fig. 9 As shown, the construction process of the present invention is divided into the following steps: 1) drilling: drilling an anchor hole 9 on the rock mass by a drill bit; 2) assembly installation: inserting the pre-assembled shell anchor assembly into the anchor hole 9, so that the pad 7 is close to the rock wall of the anchor hole 9; 3) anchoring: rotating the drive nut 8, the anchor body 6 rotates to drive the connecting sleeve 41 and the screw 42 to rotate, so that the wedge 3 inside the shell moves to the outside of the anchor hole 9 and pushes the shell to achieve fixation and prestressing on the anchor hole 9;

[0058] like Fig.10 As shown, the anchoring step can be specifically divided into the following sub-steps:

[0059] a) Initial stage: Since the connecting sleeve 41 is always pressed against the bottom surface of the expansion shell, the expansion shell inner wedge 3 will push the expansion shell sheet 1 to deform outward and cling to the hole wall when sliding into the expansion shell, thus completing the expansion shell fixation;

[0060] b) Intermediate stage: Continue to rotate the anchor rod 4. When the torque exceeds a certain value and the extrusion force of the connecting sleeve 41 exceeds the strength limit of the shell expansion connection part 10, the shell expansion connection part 10 breaks, leaving the internal space.

[0061] c) Ending stage: Continue to rotate the anchor rod 4, the screw rod 42 will drive the upper end of the anchor rod body 6 to move upward through the connecting sleeve 41, so that the anchor rod 4 elastically stretches, and applies axial preload force to the wedge 3 inside the expansion shell and the expansion shell. At this time, the axial preload force is transmitted to the rock wall of the anchor hole 9 through the anchor rod body 6, the driving nut 8 and the pad 7, completing the application of preload force on the anchor rod 4;

[0062] In the existing construction methods of expansion bolts, such as patents with application numbers CN201510711711.4 and CN201910265475.6, the bolt body needs to move outside the anchor hole during construction, resulting in the outer end of the bolt extending outward from the rock mass outside the anchor hole after the operation is completed. Based on factors such as safety and process requirements, the excess bolt body at the exposed end needs to be cut off. Currently, this cutting step relies on manual operation, which not only increases the number of operation steps and reduces construction efficiency, but also causes problems such as increased engineering costs and material waste.

[0063] With the construction method of the prestressed expansion shell anchor provided by the present invention, the expansion shell is expanded to the rock wall by driving the inner wedge 3 of the expansion shell to move along the screw of the anchor body 6. During the construction process, the anchor body 6 always stays in the anchor hole 9. Therefore, the construction method does not require a cutting step, the construction steps are simple, and it is easy to realize mechanical automation operation, thereby greatly improving work efficiency.

[0064] The above-mentioned embodiments are only preferred embodiments of the present invention and cannot be used to limit the scope of protection of the present invention. Any non-substantial changes and substitutions made by technicians in this field on the basis of the present invention shall fall within the scope of protection required by the present invention.

Claims

1. A prestressed expansion shell anchor rod, comprising an expansion shell and an expansion shell inner wedge and an anchor rod arranged at both ends of the expansion shell, characterized in that: The expansion shell comprises an expansion shell connection part and an expansion shell sheet, and the expansion shell sheet is circumferentially arranged on the expansion shell connection part; the expansion shell inner wedge is in sliding contact with the expansion shell top; the anchor rod comprises an anchor rod body, and a screw is fixedly installed on one end of the anchor rod body through a connecting sleeve, and the screw is connected to the expansion shell inner wedge through threaded transmission, and the top of the connecting sleeve is in extrusion contact with the bottom of the expansion shell; the anchor rod is rotated to drive the expansion shell inner wedge to move into the expansion shell, pushing the expansion shell sheet to deform outward until the expansion shell connection part breaks, so that the expansion shell sheet expands to the hole wall to apply prestress to the rock mass; The end of the anchor rod body is provided with a pad and a driving nut, and the two ends of the anchor rod body are respectively fixedly installed with the driving nut and the connecting sleeve, and the driving nut is set as a blind nut, and the driving nut is rotated to make the anchor rod body rotate and squeeze the shell connection part through the connecting sleeve; The prestressing process is as follows: Initial stage: rotate the anchor rod. At the beginning, since the connecting sleeve is always pressed on the bottom surface of the expansion shell, the inner wedge of the expansion shell slides into the expansion shell, pushing the expansion shell sheet to deform outward and close to the hole wall, thus completing the expansion shell fixation; Intermediate stage: Continue to rotate the anchor rod. When the torque exceeds a certain value, the extrusion pressure of the connecting sleeve exceeds the strength limit of the shell expansion connection part, and the shell expansion connection part breaks, leaving the internal space. Ending stage: Continue to rotate the anchor rod, the screw will drive the upper end of the anchor rod body to move upward through the connecting sleeve, so that the anchor rod elastically stretches and applies axial preload to the inner wedge and the expansion shell. At this time, the axial preload is transmitted to the rock wall of the anchor hole through the anchor rod body, driving nut and pad, completing the application of preload to the expansion shell anchor rod.

2. The prestressed expansion shell anchor rod according to claim 1, characterized in that: The shell expansion connection part and the shell expansion sheet are integrally formed, the inner side of the shell expansion sheet is provided with an inner conical surface and an inner annular surface, the inner side of the bottom end of the shell expansion connection part is provided with an extrusion surface adapted to the top of the connecting sleeve, and gaps are provided between adjacent shell expansion sheets.

3. The prestressed expansion shell anchor rod according to claim 1, characterized in that: The shell expansion connection part and the shell expansion sheet are separate structures. The inner side of the shell expansion sheet is provided with inner conical surface and inner annular surface. The inner side of the bottom end of the shell expansion sheet is provided with an extrusion surface adapted to the top of the connecting sleeve. A notch is provided on the shell expansion connection part.

4. The prestressed expansion shell anchor rod according to claim 1, characterized in that: The outer side of the shell expansion sheet is provided with continuously arranged saw teeth.

5. The prestressed expansion shell anchor rod according to claim 1, characterized in that: An independent extrusion head is arranged on the top of the connecting sleeve.

6. The prestressed expansion shell anchor rod according to any one of claims 1 to 5, characterized in that: The anchor rod body is configured as a hollow anchor rod, and a slurry outlet hole is configured on the connecting sleeve.

7. The prestressed expansion shell anchor rod according to claim 6, characterized in that: An anti-vibration box is arranged between the driving nut and the backing plate, and a pressure-releasing assembly is arranged at the end of the anchor rod body.

8. A construction method for a prestressed expansion shell anchor according to claim 6, characterized in that: The steps include: S1 Drilling: Drill anchor holes in the rock mass using a drill bit; S2 assembly installation: insert the pre-assembled shell expansion anchor into the anchor hole, so that the pad is close to the rock wall at the anchor hole mouth; S3 anchoring: Rotate the drive nut, the anchor rod body rotates to drive the connecting sleeve and the screw rod to rotate, so that the inner wedge of the expansion shell moves to the outside of the anchor hole and pushes the expansion shell to achieve fixation and prestressing on the anchor hole.

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