Self-expanding balloon body expansion anchor rod supporting structure and construction method
By installing a fixing cylinder, a bladder, and a sealing device on the anchor bolt, the problem of insufficient connection strength between the anchor bolt and the bladder was solved, thereby improving the stability and pull-out resistance of the anchor bolt and ensuring the anchoring effect.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- GUANGXI SHUANGXIANG GEOTECHNICAL ENG CO LTD
- Filing Date
- 2022-09-14
- Publication Date
- 2026-07-14
AI Technical Summary
In existing technologies, the connection strength between the anchor rod and the cement inside the bag is insufficient, which can easily lead to detachment or loosening and cannot effectively guarantee the anchoring effect. In particular, when encountering strong external stress, the pull-out resistance of traditional anchor rods is insufficient.
The self-expanding bladder-type expanded anchor bolt structure is adopted. By setting a fixed cylinder and a bladder on the anchor bolt body, and using sealing devices, grouting devices and limiting devices, the stable connection between the anchor bolt and the grout in the bladder is ensured, increasing the contact area and connection strength, and improving stability.
It enhances the connection strength between the anchor bolt and the grout inside the bag, improves the anchoring effect, ensures the stability and pull-out resistance of the anchor bolt, and prevents the cement from separating from or loosening the anchor bolt.
Smart Images
Figure CN115573335B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of civil engineering technology, and in particular to a self-expanding bladder-type expanded anchor support structure and its construction method. Background Technology
[0002] With the increasing intensity and depth of underground engineering, deep foundation pit support has become a major challenge restricting the efficient and safe construction of high-rise buildings. After excavation, large deformations can easily occur in the pit sidewalls and soil slopes, leading to the failure of the support structure. The safety of underground engineering projects is therefore becoming increasingly important. Traditional anchor bolts are widely used in water conservancy and hydropower, civil engineering, transportation, and municipal projects. However, the problem of anchor end failure is becoming increasingly prominent during the use of anchor bolt support. Once the anchor end fails, the anchor bolt cannot play a substantial role, and the safety of the foundation pit construction is seriously threatened.
[0003] Currently, the most common methods for anti-buoyancy measures in China's building foundations are: anti-buoyancy reinforced concrete cast-in-place piles and anti-buoyancy anchors (tension type). Anti-buoyancy piles are a conventional method with mature technology and established experience, but due to the use of reinforced concrete cages, the investment is substantial, and the concrete has poor tensile strength. Anti-buoyancy anchors (tension type) typically provide relatively low pull-out resistance. For projects with high anti-buoyancy design bearing capacity, traditional anchors are no longer effective in meeting construction needs, and the grout at the fixed end is prone to tension cracks and has poor corrosion resistance.
[0004] In related technologies, patent publication number "CN110952542A" discloses a method where, after a reinforced cage-like anchor rod is inserted into an anchor hole, concrete is injected into the bag to enlarge its diameter. This not only generates friction between the axial direction of the anchor rod and the axial direction of the anchor hole, but also creates a compressive force between the upper end face of the bag and the enlarged end face of the anchor hole, greatly increasing the pull-out resistance of the reinforced cage-like anchor rod and thus ensuring the engineering stability of the anchoring structure. Regarding the above technical solution, the inventors have discovered that, in this solution, the connection between the anchor rod and the cement inside the grouted bag is merely a steel mesh, as is common in existing technologies. Furthermore, there is no direct connection between the steel cage and the anchor rod; the connection is achieved through seals at both ends. This configuration results in insufficient connection strength between the cement inside the bag and the anchor rod, making it prone to detachment or loosening under strong external stress, thus failing to guarantee the anchoring effect. Summary of the Invention
[0005] The purpose of this invention is to provide a self-expanding bladder-type expanded anchor support structure and construction method to solve the problems existing in the prior art.
[0006] To achieve the above objectives, the present invention provides the following solution: The present invention provides a self-expanding bladder-type expanded anchor bolt support structure, comprising:
[0007] The anchor bolt body has a fixed cylinder fitted at its bottom, and a bladder fitted on the outer wall of the fixed cylinder. Both ends of the bladder are fixed to the fixed cylinder via a first sealing device and a second sealing device, respectively. A grouting device is provided at the top of the fixed cylinder. The top of the fixed cylinder is threadedly connected to the anchor bolt body via an upper fixing device, and the bottom of the fixed cylinder is threadedly connected to the bottom of the anchor bolt body via a lower fixing device. A limit device is provided at the top of the anchor bolt, and a protective head is threadedly connected to the bottom of the anchor bolt. Several limit holes are formed on the inner wall of the fixed cylinder, and an extension cylinder slides within these limit holes. Several grouting holes are circumferentially spaced at equal intervals in the middle of the outer wall of the extension cylinder. A snap-fit ring is fixedly connected to one end of the extension cylinder. An annular groove is formed on the outer wall of the limit hole. A limit ring is fixedly connected to the other end of the extension cylinder, and the limit ring is adapted to the annular groove.
[0008] Preferably, the grouting device includes an air outlet pipe and a grout inlet pipe. The bottoms of the air outlet pipe and the grout inlet pipe are respectively connected to the top of the fixed cylinder. The tops of the air outlet pipe and the grout inlet pipe are respectively fitted with an exhaust pipe and a grout injection pipe. Both the exhaust pipe and the grout injection pipe are tied to the anti-corrosion mechanism with steel wire.
[0009] Preferably, the limiting device includes a nut, which is threadedly connected to the top of the anchor rod body. A pad is fitted on the top of the anchor rod body, the bottom surface of the pad abuts against the ground, the bottom surface of the nut abuts against the top surface of the pad, and an anti-corrosion mechanism is fitted on the outer wall of the top of the anchor rod body.
[0010] Preferably, the anti-corrosion mechanism includes a sleeve fitted onto the outer wall of the anchor rod body. An upper limit ring is fixedly connected to the center of the bottom surface of the pad, and an upper sealing ring is fixedly connected to the inner wall of the upper limit ring. The top outer wall of the sleeve abuts against the inner wall of the upper sealing ring. A lower limit ring is fitted onto the outer wall of the upper fixing device. The bottom inner wall of the lower limit ring is fixedly connected to the outer wall of the upper fixing device, and a lower sealing ring is fixedly connected to the top inner wall of the lower limit ring. The bottom outer wall of the sleeve abuts against the inner wall of the lower sealing ring.
[0011] Preferably, the upper fixing device includes an upper fixing tube, the bottom of which is connected to the top of the fixing cylinder, the inner wall of which is threaded to the outer wall of the anchor rod body, and the bottom inner wall of the lower limiting ring is threaded to the outer wall of the upper fixing tube.
[0012] The lower fixing device includes a lower fixing tube, the top of which is connected to the bottom of the fixing cylinder, and the inner wall of the lower fixing tube is connected to the outer wall of the anchor rod body by a thread.
[0013] Preferably, the first sealing device includes an upper sealing ring, which is fixed to the top surface of the fixed cylinder, and the top of the bag is fixed to the outer wall of the upper sealing ring by an upper clamp.
[0014] The second sealing device includes a lower clamp, through which the bottom of the bladder is fixed to the outer wall of the lower fixing tube.
[0015] Preferably, the protective head is configured as a conical structure, and a protective cylinder is fixedly connected to the top surface of the protective head. The inner wall of the protective cylinder is connected to the outer wall of the bottom of the lower fixed tube by a thread.
[0016] The construction method for a self-expanding bladder-type expanded anchor support structure includes the following steps:
[0017] S1. Anchor assembly: Place the bladder bag on the fixed cylinder, and clamp it to the upper and lower fixed pipes at both ends of the fixed cylinder through the upper and lower clamps respectively. Pass the anchor body through the fixed cylinder and connect it to the upper and lower fixed pipes through threads. Complete the assembly of the protective head. Place the sleeve on the anchor body and perform preliminary positioning through the lower sealing ring. Then connect the exhaust pipe and the grouting pipe.
[0018] S2. Drilling: Install the drill bit on the drill rod of the drilling rig, start the drilling rig and drill downwards to the non-reaming depth. Then stop the machine and replace the reaming drill bit. Start the drilling rig to the bottom of the non-reaming section, rotate the drill rod downwards to open the reaming drill bit, and ream the hole until the specified depth of the reaming section is reached.
[0019] S3. Lower the anchor, keeping the anchor body aligned with the borehole axis, and slowly lower it to the specified depth;
[0020] S4. Grouting: The grouting pipe is connected to the grouting machine to grout into the fixed cylinder until the grout flows out of the vent pipe. Then, the grouting pipe is lifted up and the vent pipe is removed to separate the grouting pipe from the grout inlet pipe. Grouting continues until the grout overflows from the borehole. Then, the grouting pipe is removed.
[0021] S5. Install the limiting device, put the pad on the end of the anchor rod body that is exposed above the ground, so that the bottom surface of the pad abuts against the ground, while ensuring that the top outer wall of the sleeve abuts against the inner wall of the upper sealing ring, and then install the nut to make the pad fit tightly against the ground.
[0022] The present invention discloses the following technical effects: After the extension cylinder extends outward during grouting, it is inserted into the grout inside the bag. After the grout solidifies, it increases the contact area with the grout, improves the connection strength between the anchor bolt body and the grout inside the bag, enhances stability, and further strengthens the anchoring effect. Attached Figure Description
[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0024] Figure 1 This is a schematic diagram of the structure of the present invention;
[0025] Figure 2 for Figure 1 A magnified view of a portion of A1;
[0026] Figure 3 for Figure 1 A magnified view of part A2;
[0027] Figure 4 for Figure 1 A magnified view of a portion of A3 paper;
[0028] Figure 5 for Figure 1 A magnified view of a portion of an A4 sheet;
[0029] Figure 6 for Figure 1 A magnified view of a portion of an A5 sheet of paper;
[0030] Figure 7 for Figure 1 A magnified view of a portion of A6 paper;
[0031] Figure 8 This is a flowchart of the construction method in this invention;
[0032] The components are as follows: 1. Anchor bolt body; 2. Fixing cylinder; 3. Bag; 4. Protective head; 5. Extension cylinder; 6. Grouting hole; 7. Clip ring; 8. Limiting ring; 9. Air outlet pipe; 10. Grout inlet pipe; 11. Exhaust pipe; 12. Grouting pipe; 13. Nut; 14. Gasket; 15. Sleeve; 16. Upper limit ring; 17. Upper sealing ring; 18. Lower limit ring; 19. Lower sealing ring; 20. Upper fixing pipe; 21. Lower fixing pipe; 22. Upper sealing ring; 23. Upper clamp; 24. Lower clamp; 25. Protective cylinder. Detailed Implementation
[0033] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0034] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.
[0035] Reference Figure 1-8 The present invention provides a self-expanding bladder-type expanded anchor bolt support structure, comprising:
[0036] An anchor bolt body 1 has a fixing cylinder 2 fitted at its bottom. A bag 3 is fitted on the outer wall of the fixing cylinder 2. The two ends of the bag 3 are fixed to the fixing cylinder 2 through a first sealing device and a second sealing device, respectively. A grouting device is provided at the top of the fixing cylinder 2. The top of the fixing cylinder 2 is threadedly connected to the anchor bolt body 1 through an upper fixing device. The bottom of the fixing cylinder 2 is threadedly connected to the bottom of the anchor bolt body 1 through a lower fixing device. A limit device is provided at the top of the anchor bolt. A protective head 4 is threadedly connected to the bottom of the anchor bolt. Several limit holes are opened on the inner wall of the fixing cylinder 2. An extension cylinder 5 slides in contact with the limit holes. Several grouting holes 6 are opened at equal intervals in the circumferential direction in the middle of the outer wall of the extension cylinder 5. A snap ring 7 is fixedly connected to one end of the extension cylinder 5. An annular groove is opened on the outer wall at the outer opening of the limit hole. A limit ring 8 is fixedly connected to the other end of the extension cylinder 5. The limit ring 8 is adapted to the annular groove.
[0037] The set bag 3 is sealed by the first and second sealing devices to ensure the sealing of the grout inside the bag 3, thereby achieving stable expansion of the bag 3 and improving stability. The set upper and lower fixing devices improve the connection strength between the anchor rod body 1 and the fixing cylinder 2. The set limiting device is used to limit the top of the anchor rod. After grouting by the grouting device, the grout injected into the fixing cylinder 2 fills the fixed cylinder 2 and pushes the extension cylinder 5 outward until the grouting hole 6 on the extension cylinder 5 extends out of the fixed cylinder 2 and communicates with the inner cavity of the bag 3, so that the grout is injected into the bag 3, causing the bag 3 to expand and then clamp the inner wall of the expanded section. After the set extension cylinder 5 extends outward, it is inserted into the grout inside the bag 3. After the grout solidifies, it increases the contact area with the grout, improves the connection strength between the anchor rod body 1 and the grout inside the bag 3, improves stability, and further enhances the anchoring effect.
[0038] The scheme is further optimized. The grouting device includes an air outlet pipe 9 and a grout inlet pipe 10. The bottom of the air outlet pipe 9 and the grout inlet pipe 10 are respectively connected to the top of the fixed cylinder 2. The top of the air outlet pipe 9 and the grout inlet pipe 10 are respectively fitted with an exhaust pipe 11 and a grout injection pipe 12. The exhaust pipe 11 and the grout injection pipe 12 are both tied to the anti-corrosion mechanism with steel wire.
[0039] The grouting pipe 12 is connected to the external grouting machine to realize grouting inside the bag 3 and the borehole. The exhaust pipe 11 can expel the air inside the fixed cylinder 2 when grouting, so that the fixed cylinder 2 and the bag 3 are filled with grout and the voids are avoided.
[0040] Further optimization of the scheme: the limiting device includes a nut 13, which is threadedly connected to the top of the anchor rod body 1. A pad 14 is fitted on the top of the anchor rod body 1, with the bottom surface of the pad 14 abutting against the ground. The bottom surface of the nut 13 abuts against the top surface of the pad 14. An anti-corrosion mechanism is fitted on the outer wall of the top of the anchor rod body 1.
[0041] The nut 13 is connected to the anchor rod body 1 by a thread. When screwed downward, it presses the pad 14 downward, so that the pad 14 fits tightly against the ground, thereby tightening the anchor rod.
[0042] The scheme is further optimized. The anti-corrosion mechanism includes a sleeve 15, which is sleeved on the outer wall of the anchor body 1. An upper limit ring 16 is fixedly connected to the center of the bottom surface of the pad 14. An upper sealing ring 17 is fixedly connected to the inner wall of the upper limit ring 16. The top outer wall of the sleeve 15 abuts against the inner wall of the upper sealing ring 17. A lower limit ring 18 is sleeved on the outer wall of the upper fixing device. The bottom inner wall of the lower limit ring 18 is fixedly connected to the outer wall of the upper fixing device. A lower sealing ring 19 is fixedly connected to the top inner wall of the lower limit ring 18. The bottom outer wall of the sleeve 15 abuts against the inner wall of the lower sealing ring 19.
[0043] The sleeve 15 covers the anchor body 1 through the upper sealing ring 17 and the lower sealing ring 19, thus preventing corrosion at the top of the anchor body 1.
[0044] Further optimization of the scheme: the upper fixing device includes an upper fixing tube 20, the bottom of the upper fixing tube 20 is connected to the top of the fixing cylinder 2, the inner wall of the upper fixing tube 20 is connected to the outer wall of the anchor body 1 by a thread, and the bottom inner wall of the lower limiting ring 18 is connected to the outer wall of the upper fixing tube 20 by a thread.
[0045] The lower fixing device includes a lower fixing tube 21, the top of which is connected to the bottom of the fixing cylinder 2, and the inner wall of the lower fixing tube 21 is connected to the outer wall of the anchor rod body 1 by a thread.
[0046] The upper fixing tube 20 and the lower fixing tube 21 are used to fix the anchor rod body 1 by threaded connection, thereby fixing the anchor rod body 1.
[0047] Further optimization of the scheme: the first sealing device includes an upper sealing ring 22, which is fixed to the top surface of the fixed cylinder 2, and the top of the bag 3 is fixed to the outer wall of the upper sealing ring 22 by an upper clamp 23.
[0048] The second sealing device includes a lower clamp 24, and the bottom of the bag 3 is fixed to the outer wall of the lower fixing tube 21 by the lower clamp 24.
[0049] The upper clamp 23 and lower clamp 24 are designed to seal both ends of the bag 3, preventing leakage of slurry.
[0050] Further optimization of the design: the protective head 4 is set as a conical structure, and a protective cylinder 25 is fixed to the top surface of the protective head 4. The inner wall of the protective cylinder 25 is connected to the bottom outer wall of the lower fixed pipe 21 by threads.
[0051] The protective head 4 can protect the bag 3 when the anchor rod is lowered, and prevent the bag 3 from being scratched and damaged.
[0052] The construction method for a self-expanding bladder-type expanded anchor support structure includes the following steps:
[0053] S1. Anchor assembly: The bag 3 is fitted onto the fixed cylinder 2. The upper clamp 23 and the lower clamp 24 are respectively clamped to the upper fixed pipe 20 and the lower fixed pipe 21 at both ends of the fixed cylinder 2. The anchor body 1 is passed through the fixed cylinder 2 and connected to the upper fixed pipe 20 and the lower fixed pipe 21 by threads. The protective head 4 is assembled. The sleeve 15 is fitted onto the anchor body 1 and initially positioned by the lower sealing ring 19. Then the exhaust pipe 11 and the grouting pipe 12 are connected.
[0054] S2. Drilling: Install the drill bit on the drill rod of the drilling rig, start the drilling rig and drill downwards to the non-reaming depth. Then stop the machine and replace the reaming drill bit. Start the drilling rig to the bottom of the non-reaming section, rotate the drill rod downwards to open the reaming drill bit, and ream the hole until the specified depth of the reaming section is reached.
[0055] S3. Lower the anchor, keeping the anchor body 1 aligned with the borehole axis, and slowly lower it to the specified depth;
[0056] S4. Grouting: Grouting pipe 12 is connected to grouting machine and grouts into fixed cylinder 2 until grout flows out of vent pipe 11. Then, grouting pipe 12 is lifted up and vent pipe 11 is removed. Grouting pipe 12 is separated from grout inlet pipe 10 and grouting continues until grout overflows from the borehole. Grouting is then stopped and grouting pipe 12 is removed.
[0057] S5. Install the limiting device, put the pad 14 on the end of the anchor body 1 that is exposed above the ground, so that the bottom surface of the pad 14 abuts against the ground, while ensuring that the top outer wall of the sleeve 15 abuts against the inner wall of the upper sealing ring 17, and then install the nut 13 to make the pad 14 fit tightly against the ground.
[0058] In the description of this invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this invention, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.
[0059] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.
Claims
1. A self-expanding bladder-type expanded-body anchor support structure, characterized in that, include: An anchor bolt body (1) has a fixing cylinder (2) fitted at its bottom. A bladder (3) is fitted on the outer wall of the fixing cylinder (2). The two ends of the bladder (3) are fixed to the fixing cylinder (2) by a first sealing device and a second sealing device, respectively. A grouting device is provided at the top of the fixing cylinder (2). The top of the fixing cylinder (2) is threaded to the anchor bolt body (1) by an upper fixing device. The bottom of the fixing cylinder (2) is threaded to the bottom of the anchor bolt body (1) by a lower fixing device. The top of the rod is provided with a limiting device, and the bottom of the anchor rod is connected to a protective head (4) by a thread. Several limiting holes are opened on the inner wall of the fixed cylinder (2). An extension cylinder (5) is slidably contacted in the limiting hole. Several grouting holes (6) are opened at equal intervals in the circumferential direction in the middle of the outer wall of the extension cylinder (5). A snap ring (7) is fixedly connected to one end of the extension cylinder (5). An annular groove is opened on the outer wall at the outer opening of the limiting hole. A limiting ring (8) is fixedly connected to the other end of the extension cylinder (5). The limiting ring (8) is adapted to the annular groove.
2. The self-expanding bladder-type expanded anchor bolt support structure according to claim 1, characterized in that: The grouting device includes an air outlet pipe (9) and a grout inlet pipe (10). The bottoms of the air outlet pipe (9) and the grout inlet pipe (10) are respectively connected to the top of the fixed cylinder (2). The tops of the air outlet pipe (9) and the grout inlet pipe (10) are respectively fitted with an exhaust pipe (11) and a grout injection pipe (12). The exhaust pipe (11) and the grout injection pipe (12) are both tied to the anti-corrosion mechanism with steel wire.
3. The self-expanding bladder-type expanded anchor bolt support structure according to claim 2, characterized in that: The limiting device includes a nut (13), which is threaded to the top of the anchor rod body (1). A pad (14) is fitted on the top of the anchor rod body (1). The bottom surface of the pad (14) abuts against the ground. The bottom surface of the nut (13) abuts against the top surface of the pad (14). The anti-corrosion mechanism is fitted on the outer wall of the top of the anchor rod body (1).
4. The self-expanding bladder-type expanded anchor bolt support structure according to claim 3, characterized in that: The anti-corrosion mechanism includes a sleeve (15), which is fitted on the outer wall of the anchor body (1). An upper limit ring (16) is fixedly connected to the center of the bottom surface of the pad (14). An upper sealing ring (17) is fixedly connected to the inner wall of the upper limit ring (16). The top outer wall of the sleeve (15) abuts against the inner wall of the upper sealing ring (17). A lower limit ring (18) is fitted on the outer wall of the upper fixing device. The bottom inner wall of the lower limit ring (18) is fixedly connected to the outer wall of the upper fixing device. A lower sealing ring (19) is fixedly connected to the top inner wall of the lower limit ring (18). The bottom outer wall of the sleeve (15) abuts against the inner wall of the lower sealing ring (19).
5. The self-expanding bladder-type expanded anchor bolt support structure according to claim 4, characterized in that: The upper fixing device includes an upper fixing tube (20), the bottom of the upper fixing tube (20) is connected to the top of the fixing cylinder (2), the inner wall of the upper fixing tube (20) is connected to the outer wall of the anchor body (1) by a thread, and the bottom inner wall of the lower limiting ring (18) is connected to the outer wall of the upper fixing tube (20) by a thread. The lower fixing device includes a lower fixing tube (21), the top of which is connected to the bottom of the fixing cylinder (2), and the inner wall of the lower fixing tube (21) is connected to the outer wall of the anchor body (1) by a thread.
6. The self-expanding bladder-type expanded anchor bolt support structure according to claim 5, characterized in that: The first sealing device includes an upper sealing ring (22), which is fixed to the top surface of the fixed cylinder (2), and the top of the bag (3) is fixed to the outer wall of the upper sealing ring (22) by an upper clamp (23); The second sealing device includes a lower clamp (24), and the bottom of the sac (3) is fixed to the outer wall of the lower fixing tube (21) by the lower clamp (24).
7. The self-expanding bladder-type expanded anchor bolt support structure according to claim 6, characterized in that: The protective head (4) is configured as a conical structure, and a protective cylinder (25) is fixedly connected to the top surface of the protective head (4). The inner wall of the protective cylinder (25) is connected to the bottom outer wall of the lower fixed tube (21) by a thread.
8. A construction method for a self-expanding bladder-type expanded-body anchor support structure, as described in claim 7, characterized in that... Includes the following steps: S1. Anchor assembly: The bag (3) is fitted onto the fixed cylinder (2). The upper clamp (23) and lower clamp (24) are clamped to the upper fixed pipe (20) and lower fixed pipe (21) at both ends of the fixed cylinder (2) respectively. The anchor body (1) passes through the fixed cylinder (2) and is connected to the upper fixed pipe (20) and lower fixed pipe (21) by threads. The protective head (4) is assembled. The sleeve (15) is fitted onto the anchor body (1) and initially positioned by the lower sealing ring (19). Then the exhaust pipe (11) and grouting pipe (12) are connected. S2. Drilling: Install the drill bit on the drill rod of the drilling rig, start the drilling rig and drill downwards to the non-reaming depth. Then stop the machine and replace the reaming drill bit. Start the drilling rig to the bottom of the non-reaming section, rotate the drill rod downwards to open the reaming drill bit, and ream the hole until the specified depth of the reaming section is reached. S3. Lower the anchor, keeping the anchor body (1) aligned with the borehole axis, and slowly lower it to the specified depth; S4. Grouting: The grouting pipe (12) is connected to the grouting machine and grouts into the fixed cylinder (2) until the grout flows out of the exhaust pipe (11). Then, the grouting pipe (12) is lifted up and the exhaust pipe (11) is removed. After the grouting pipe (12) is separated from the grout inlet pipe (10), grouting continues until the grout overflows from the borehole and grouting is stopped. The grouting pipe (12) is then removed. S5. Install the limiting device, put the pad (14) on the end of the anchor body (1) that is exposed on the ground, so that the bottom surface of the pad (14) abuts against the ground, while ensuring that the top outer wall of the sleeve (15) abuts against the inner wall of the upper sealing ring (17), and then install the nut (13) so that the pad (14) fits tightly against the ground.