Large-diameter finished rolled threaded steel prestressed anti-floating anchor rod structure and construction method

Abstract

The application discloses a large-diameter finished rolled threaded steel prestressed anti-floating anchor rod structure and method, solves the problem of prestress loss in the prior art, has the beneficial effect of enhancing the integrity and structural property of the anti-floating anchor rod to reduce the prestress loss, and specifically has the following technical scheme: a large-diameter finished rolled threaded steel prestressed anti-floating anchor rod structure, which comprises an anchor rod body made of finished rolled threaded steel, the anchor rod body is a prestressed anchor rod body, the anchor rod body is inserted into an anchor hole, both sides of the top end of the anchor hole are concrete cushion layers, a prestressed cylinder comprises a pressure-bearing piece and a cylinder body, the pressure-bearing piece is located at the top end of the cylinder body, the cylinder body is located in the ring direction of the anchor rod body, the anchor rod body is arranged beyond the pressure-bearing piece, the pressure-bearing piece is located above the concrete cushion layers, the part of the lower surface of the pressure-bearing piece located outside the cylinder body is sealingly connected between the concrete cushion layers, a first locking piece is located on the surface of the pressure-bearing piece to lock the anchor rod body, and a spiral rib is sleeved on the anchor rod body.

Description

Technical Field

[0001] This invention relates to the field of foundation engineering construction (anti-buoyancy of underground engineering) technology, and in particular to a prestressed anti-buoyancy anchor structure and construction method of large-diameter precision rolled threaded steel. Background Technology The statements in this section are merely background information related to the present invention and do not necessarily constitute prior art.

[0002] Anti-buoyancy anchors, as an important technology in rock and soil anchoring, are widely used in anti-buoyancy projects due to their advantages such as strong adaptability to strata, stress dispersion, simple construction, and low cost. In conventional anti-buoyancy projects, the anchor rod body is mostly made of ordinary hot-rolled steel bars. However, with the increasing requirements for anti-buoyancy, the poor load-bearing capacity of traditional steel bars has become an obstacle to the development of structural anti-buoyancy.

[0003] When the anchorage bearing layer is deeply buried, the required anchor length is large, and the anchor head displacement exceeds the limit (design requirements), prestressed anchors should be used. The prestress locking value of the prestressed anchor should be determined based on the amount of excess displacement to be eliminated. Currently, the common method is to pre-drill holes in the basement foundation slab and use the basement foundation slab as a supporting member to apply prestress. However, this method has the following unavoidable drawbacks: First, the prestressing of the anchor bolts could not be completed before the basement foundation slab was poured, leading to overlapping work processes and extending the construction period. Second, most of the applied prestress was transferred to the ground, with almost none being transferred to the grout in the anchor holes, thus failing to improve the stress conditions of the grout. Third, the basement foundation slab required pre-drilled holes, creating the need for subsequent sealing work and the potential for leakage. Fourth, the prestressed anchor bolts lacked sufficient corrosion resistance.

[0004] Therefore, unless the basement foundation slab has been completed before the anchor bolts or the required prestressing locking value is large enough, it is generally not recommended to apply prestress by reserving holes in the basement foundation slab. Instead, in-hole prestressing should be used.

[0005] Currently, there are several publicly available similar technologies for applying prestress within holes. However, the inventors have discovered that existing methods for applying prestress within holes still have the following shortcomings: 1) The range of applicable prestress is insufficient, and the bearing capacity of the grouting body is limited; 2) The integrity and structural integrity of the anti-buoyancy anchor rods cannot be guaranteed after the basement floor slab is poured, and there is a risk of prestress loss; 3) The issue of secondary grouting of the anchor body was not considered, which could not effectively guarantee the compactness and integrity of the grout body. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the purpose of this invention is to provide a prestressed anti-buoyancy anchor structure for large-diameter precision-rolled threaded steel bars, thereby increasing the prestress application range of the anti-buoyancy anchor and enhancing its overall integrity and structural strength.

[0007] To achieve the above objectives, the present invention is implemented through the following technical solution: A prestressed anti-buoyancy anchor structure made of large-diameter precision-rolled threaded steel includes an anchor rod body made of precision-rolled threaded steel. The anchor rod body is a prestressed anchor rod body, which is inserted into an anchor hole. The top two sides of the anchor hole are concrete pads. The prestressed cylinder includes a bearing member and a cylinder body. The bearing member is located at the top of the cylinder body, and the cylinder body is located circumferentially around the anchor rod body. The anchor rod body extends beyond the bearing member. The bearing member is located above the concrete pads. The lower surface of the bearing member, located outside the cylinder body, is sealed to the concrete pads. A first locking member is located on the surface of the bearing member to lock the anchor rod body. A spiral reinforcement is fitted onto the portion of the anchor rod body that extends beyond the first locking member to increase the contact area between the anchor rod body and the concrete layer. The spiral reinforcement is locked by a second locking member.

[0008] The aforementioned prestressed anti-buoyancy anchor structure uses large-diameter precision-rolled threaded steel for the anchor body, which has extremely high tensile strength. It allows for the application of prestress within a wide stress range according to construction requirements. A prestressing cylinder is installed in the anchoring section, effectively improving the bearing capacity of the grout and increasing the prestress application range of the anti-buoyancy anchor. Spiral reinforcement is installed on the top side of the anchor body, acting as stirrups after the foundation slab is poured. This effectively increases the contact area between the anchor body and the foundation slab, greatly enhancing the anchoring strength between them, reducing slippage deformation, strengthening the overall integrity and structure of the anti-buoyancy anchor, and effectively minimizing prestress loss.

[0009] As described above, in a prestressed anti-buoyancy anchor structure for large-diameter precision-rolled threaded steel bars, the bearing component is a bearing plate, which is welded to the cylinder. The diameter or side length of the bearing plate is greater than the outer diameter of the cylinder. By setting the prestressed cylinder, the bearing capacity of the grouting body can be effectively improved, and the prestressing application range of the anti-buoyancy anchor can be increased. The outer diameter of the cylinder is less than or equal to the diameter of the anchor hole, and the side length or diameter of the pressure-bearing member is greater than the diameter of the anchor hole.

[0010] As described above, in a prestressed anti-buoyancy anchor structure for large-diameter precision-rolled threaded steel bars, a first hole is reserved in the middle of the bearing member for the anchor rod body to pass through, and a second hole is reserved on the side of the first hole to facilitate grouting. The length of the cylinder is greater than or equal to three times the diameter of the anchor hole, which allows the prestress to be transferred to the grouting body at a deeper depth through the lower end of the cylinder. The confining pressure of the deeper soil can be used to improve the stress conditions of the grouting body, increase its strength, and enable it to bear greater prestress. The wall thickness of the cylinder is 3-5mm.

[0011] As described above, in a prestressed anti-buoyancy anchor structure for large-diameter precision-rolled threaded steel, a water-swellable rubber waterstop strip is provided between the lower surface of the bearing component located on the outer side of the cylinder and the concrete pad layer. The water-swellable rubber waterstop strip is located in the circumferential direction of the cylinder, which can effectively prevent groundwater leakage.

[0012] As described above, in a prestressed anti-buoyancy anchor structure for large-diameter precision-rolled threaded steel bars, the first locking element is a first nut, and the second locking element is a second nut. A pad is provided between the second locking member and the spiral rib.

[0013] Secondly, the present invention also provides a construction method for a large-diameter precision-rolled threaded steel prestressed anti-buoyancy anchor rod, which adopts the aforementioned large-diameter precision-rolled threaded steel prestressed anti-buoyancy anchor rod structure.

[0014] The construction method for a large-diameter precision-rolled threaded steel prestressed anti-buoyancy anchor rod, as described above, includes the following: Install the centering device to the set position of the anchor rod body, lower the anchor rod body into the anchor hole, and place the positioning component on the surface of the concrete pad when the centering device is close to the anchor hole opening. Continue to lower the anchor rod body, and stop lowering the anchor rod body when the centering device contacts the positioning component, so that the length of the anchor rod body entering the anchor hole is the set value. Place the grouting pipe into the anchor hole and inject grout into the anchor hole until the grouting body fills the anchor hole, thus ending one grouting cycle. Remove the positioning components, fit the prestressed sleeve onto the anchor rod body, insert the sleeve into the anchor hole, place the bearing component above the concrete pad, and place the first locking component on the anchor rod body above the bearing component; The grouting pipe passes through the pressure-bearing component and re-enters the anchor hole for secondary grouting. After the grout from the secondary grouting has solidified, the bearing beam, jack, and second locking device are sequentially fitted onto the anchor rod body. The jack is then activated to apply prestress to the anchor rod body. After the prestress is applied, the applied prestress is locked by the first locking device. After locking is completed, remove the second locking component, jack and bearing beam, put the spiral reinforcement on the top of the anchor rod, and compress and lock the spiral reinforcement by the second locking component.

[0015] As described above, the construction method enables accurate lowering of the anchor bolt length using a centering device and positioning components. After lowering, the anchor hole is grouted once, followed by the installation of the prestressed cylinder. After the prestressed cylinder is installed, a second grouting is performed. After grouting, the prestressed cylinder and anchor bolt body are prestressed and locked using jacks. After locking, spiral reinforcement is installed on the outside of the exposed anchor hole of the anchor bolt, which can effectively increase the contact area between the anchor bolt body and the subsequent basement foundation slab, greatly improving the anchoring strength between the anchor bolt body and the foundation slab.

[0016] As described above, a construction method for a large-diameter precision-rolled threaded steel prestressed anti-buoyancy anchor rod includes a centering device comprising a centering device cylinder of a set length. The inner surface of the centering device cylinder is threadedly connected to and fixed to the anchor rod body. A support plate is provided at the bottom of the centering device cylinder, and reinforcing ribs are provided between the support plate and the centering device cylinder. Several grooves are provided circumferentially on the support plate to prevent the anchor rod body from rolling when it is laid horizontally on the ground.

[0017] As described above, in the construction method of a prestressed anti-buoyancy anchor rod for large-diameter precision rolled threaded steel, after the positioning component is removed, a water-swellable rubber waterstop strip is placed around the anchor hole opening. After the prestressing of the anchor rod body is applied and locked, water is sprayed between the bearing component and the concrete pad to cause the water-swellable rubber waterstop strip to expand. The positioning component has an isosceles triangle outline. An opening is provided on the base of the positioning component for installation. The side length of the opening is greater than the diameter of the anchor rod and less than the side length or diameter of the centering device support plate. The positioning component allows the anchor rod to pass through but prevents the centering device from passing through, thus achieving the positioning function and fixing the anchoring length.

[0018] As described above, in a construction method for a large-diameter precision-rolled threaded steel prestressed anti-buoyancy anchor rod, the longitudinal section of the bearing beam is portal-shaped, and the inner diameter or side length of the lower half of the bearing beam is greater than the side length or inner diameter of the bearing member. Before the centering device is installed on the anchor rod body, the anchor rod body is coated with an anti-corrosion coating in the circumferential direction. The secondary grouting uses pressure grouting, which can eliminate voids, remove excess air bubbles, make the grout body dense, and ensure that the grout body reaches or exceeds the design strength of the grout after solidification.

[0019] The beneficial effects of the present invention are as follows: 1) The anchor rod body in this invention is made of large-diameter precision-rolled threaded steel, which has extremely high tensile strength. It can apply prestress over a wide range of stresses according to construction requirements. In underground buildings (structures), it can greatly improve the load-bearing capacity of the anti-buoyancy anchor rod, limit the overall deformation of the structure, and improve the safety of the building. The prestressed cylinder set in the anchoring section can effectively improve the load-bearing capacity of the grouting body and increase the prestressing application range of the anti-buoyancy anchor rod. Spiral reinforcement is installed on the top side of the anchor rod, which acts as stirrup after the foundation slab is poured. This effectively increases the contact area between the anchor rod and the foundation slab, greatly improves the anchoring strength between the anchor rod and the foundation slab, reduces the slippage deformation between the foundation slab and the anchor rod, enhances the integrity and structure of the anti-buoyancy anchor, and effectively reduces the prestress loss of the anti-buoyancy anchor.

[0020] 2) In this invention, a second hole is reserved on the pressure-bearing component for secondary grouting. The secondary grouting adopts pressure grouting, which can eliminate voids, remove excess air bubbles, make the grout body dense, and ensure that the grout body reaches or exceeds the design strength of the grout after solidification. In this invention, a water-swellable rubber waterstop strip is set on the lower surface of the pressure-bearing component, which can effectively prevent the leakage of groundwater.

[0021] 3) In this invention, the length of the cylinder is greater than or equal to three times the diameter of the anchor hole, which allows the lower end of the cylinder to transfer the prestress to the grouting body at a deeper depth. The confining pressure of the deeper soil can be used to improve the stress conditions of the grouting body, increase its strength, and enable it to bear greater prestress.

[0022] 4) The anti-buoyancy anchor construction method of the present invention can conveniently and flexibly apply prestress to the anti-buoyancy anchor and accurately lock the prestress of the anchor, and effectively increase the anchoring force between the anti-buoyancy anchor and the foundation plate.

[0023] 5) The present invention uses a centering device and positioning components during the construction of the anti-buoyancy anchor rod to ensure that the anchor rod body is in the central position in the anchor hole, and to ensure that the anchorage length of the anchor rod body in the anchor hole is consistent with the design, so as to avoid insufficient anchorage length affecting the pull-out bearing capacity of the anti-buoyancy anchor rod.

[0024] 6) The present invention applies an anti-corrosion coating to the anchor rod body, which can effectively protect the anchor rod body from rust, prevent corrosive ions such as chloride ions from corroding the anti-floating anchor rod, improve the service life of the anti-floating anchor rod, and improve the safety of the anti-floating structure. Attached Figure Description

[0025] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0026] Figure 1This is a schematic diagram of the prestressing loading process of a large-diameter precision-rolled threaded steel prestressed anti-buoyancy anchor rod structure according to one or more embodiments of the present invention.

[0027] Figure 2 This is a schematic diagram of a prestressed anti-buoyancy anchor structure for large-diameter precision-rolled threaded steel bars according to one or more embodiments of the present invention.

[0028] Figure 3 This is a front view of the installation of the anchor rod body in a prestressed anti-buoyancy anchor rod structure for large-diameter precision rolled threaded steel according to one or more embodiments of the present invention.

[0029] Figure 4 This is a top view of the installation of the anchor rod body in a prestressed anti-buoyancy anchor rod structure for large-diameter precision rolled threaded steel according to one or more embodiments of the present invention.

[0030] Figure 5 This is a schematic diagram of the prestressed cylinder in a prestressed anti-buoyancy anchor structure for large-diameter precision rolled threaded steel according to one or more embodiments of the present invention.

[0031] Figure 6 This is a schematic diagram of the pressure-bearing component in a prestressed anti-buoyancy anchor structure for large-diameter precision-rolled threaded steel according to one or more embodiments of the present invention.

[0032] Figure 7 This is a schematic diagram of the cylinder in a prestressed anti-buoyancy anchor rod structure for large-diameter precision rolled threaded steel according to one or more embodiments of the present invention.

[0033] Figure 8 This is a top view of the centering device in a prestressed anti-buoyancy anchor structure for large-diameter precision-rolled threaded steel according to one or more embodiments of the present invention.

[0034] Figure 9 This is a front view of the centering device in a prestressed anti-buoyancy anchor structure for large-diameter precision-rolled threaded steel according to one or more embodiments of the present invention.

[0035] Figure 10 This is a schematic diagram of a positioning tripod in a prestressed anti-buoyancy anchor structure for large-diameter precision rolled threaded steel according to one or more embodiments of the present invention.

[0036] The diagram exaggerates the spacing or dimensions between parts to show their positions; the diagram is for illustrative purposes only.

[0037] The components are: 1. Centerer; 1-1. Centerer cylinder; 1-2. Support plate; 1-3. Groove; 1-4. Stiffening rib; 2. Positioning tripod; 3. Second nut; 4. Washer plate; 5. Through-hole jack; 6. Bearing beam; 7. First nut; 8. Prestressed cylinder; 8-1. Bearing component; 8-2. Cylinder body; 9. Water-swellable rubber waterstop strip; 10. Waterproof layer; 11. Concrete pad; 12. Anchor rod body; 13. Anti-corrosion coating; 14. Anchor hole; 15. Grouting body; 16. Spiral reinforcement; 17. Grouting pipe. Detailed Implementation

[0038] It should be noted that the following detailed description is illustrative and intended to provide further explanation of the invention. Unless otherwise specified, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0039] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, unless otherwise expressly indicated by the invention, the singular form is also intended to include the plural form. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof. As described in the background section, existing anti-buoyancy anchor rods suffer from insufficient prestress. To address this technical problem, this invention proposes a prestressed anti-buoyancy anchor rod structure made of large-diameter precision-rolled threaded steel.

[0040] Example 1 In a typical embodiment of the present invention, reference is made to Figure 2 As shown, a prestressed anti-buoyancy anchor structure made of large-diameter precision-rolled threaded steel includes an anchor rod body 12 made of precision-rolled threaded steel. The anchor rod body 12 is a prestressed anchor rod body, which is inserted into an anchor hole 14. The top two sides of the anchor hole are concrete pads 11. The prestressed cylinder 8 includes a bearing member 8-1 and a cylinder body 8-2. The bearing member 8-1 is located at the top of the cylinder body 8-2, and the cylinder body 8-2 is located circumferentially around the anchor rod body 12. The anchor rod body 12 extends beyond the bearing member. The bearing member 8-1 is located above the concrete pads 11. The lower surface of the bearing member located outside the cylinder body is sealed to the concrete pads 11. A first locking member is located on the surface of the bearing member to lock the anchor rod body 12. A spiral reinforcement 16 is fitted onto the part of the anchor rod body that extends beyond the first locking member to increase the contact area between the anchor rod body and the concrete layer. The spiral reinforcement is locked by a second locking member.

[0041] In this embodiment, the anchor rod 12 is made of PSB precision-rolled threaded steel, and the rod diameter is typically greater than or equal to 32mm. The specific diameter is determined based on the pull-out bearing capacity and design requirements of the anti-buoyancy anchor. In this embodiment, PSB precision-rolled threaded steel with a diameter of 32mm is used.

[0042] It should be noted that, for reference Figure 5 As shown, the pressure-bearing component 8-1 is a pressure plate, which is square or round. The pressure plate is welded to the cylinder 8-2. The diameter or side length of the pressure plate is greater than the outer diameter of the cylinder 8-2. By setting the prestressed cylinder 8, the bearing capacity of the grouting body 15 can be effectively improved and the prestressing application range of the anti-buoyancy anchor rod can be increased. The outer diameter of the cylinder 8-2 is less than or equal to the diameter of the anchor hole 14, and the side length or diameter of the pressure plate is greater than the diameter of the anchor hole.

[0043] It should be explained that both the pressure plate and the cylinder 8-2 are made of Q235B or Q335B steel, with the pressure plate being a square steel plate of 250mm × 250mm × 10mm. The wall thickness of the cylinder 8-2 can be between 3 and 5mm, and the confining pressure of the deeper soil can be used to improve the stress conditions of the grouting body 15, increasing its strength and enabling it to withstand greater prestress. In this embodiment, the pressure plate is made of Q335B steel, with a first hole diameter of 32mm, and the cylinder 8-2 is made of Q335B steel with a wall thickness of 4mm, an outer diameter of 150mm, and a length of 500mm.

[0044] refer to Figure 6 As shown, the bearing member 8-1 has a first hole reserved in the middle for the anchor rod 12 to pass through, and the bearing member also has a second hole reserved on the side of the first hole to facilitate grouting; the diameter of the first hole in the middle is adjusted according to the diameter of the anchor rod 12, and needs to match the diameter of the anchor rod 12 so that the anchor rod 12 can pass through freely; the diameter of the second hole is adjusted according to the diameter of the grouting pipe 17 so that the grouting pipe 17 can pass through freely.

[0045] refer to Figure 7 As shown, cylinder 8-2 is a cylindrical body with a set length. The length of the cylinder is greater than or equal to three times the diameter of the anchor hole, which allows the lower end of the cylinder to transfer the prestress to the grouting body at a deeper depth. The confining pressure of the deeper soil can be used to improve the stress conditions of the grouting body, increase its strength, and enable it to bear greater prestress. The wall thickness of the cylinder is 3-5mm.

[0046] In addition, the pressure-bearing component 8-1 is located above the concrete pad 11 part of the anchor hole 14 opening, and a water-swellable rubber waterstop strip 9 is installed between it and the anchor hole 14 opening. The water-swellable rubber waterstop strip 9 is located in the circumferential direction of the cylinder body, which can effectively prevent the leakage of groundwater. The cylinder body 8-2 is located at the anchor hole 14 opening part, which plays a role in preventing corrosion of the end of the anchor rod body 12.

[0047] In some examples, the water-swellable rubber waterstop 9 is located between the bearing member 8-1 and the concrete cushion layer 11. It is generally available in sizes of 30mm×20mm, 20mm×15mm, and 30mm×40mm. Compared with ordinary rubber waterstops, the water-swellable rubber waterstop 9 expands and deforms 2 to 3 times after encountering water, filling all irregular surfaces, cavities, and gaps in the joint. At the same time, it generates huge contact pressure, which can effectively prevent groundwater leakage. Specifically, a 30mm×20mm water-swellable rubber waterstop 9 can be used.

[0048] In this embodiment, the first locking element is the first nut 7, and the second locking element is the second nut 3; a pad 4 is provided between the second nut 3 and the spiral rib 16.

[0049] Specifically, the first nut 7 and the second nut 3 are made of Q235B or Q335B steel, with a wall thickness between 4mm and 8mm and an inner diameter between 32mm and 40mm, adjusted according to the diameter of the anchor rod 12. They are coupled with the diameter of the anchor rod 12 and have threads on the inside, allowing the second nut 3 to be tightly connected to and firmly fixed to the anchor rod 12. The second nut 3 is located above the pad 4, serving to fix the spiral reinforcement 16 and compress it to a certain extent, ensuring that the spiral reinforcement 16 can be vertically fixed to the end of the anchor rod 12. The first nut 7 is located above the bearing member 8-1, serving to lock the prestress. Specifically, the second nut 3 and the first nut 7 are made of Q335B steel, with an inner diameter of 32mm and a wall thickness of 6mm.

[0050] After installation, the pad 4 is located between the second nut 3 and the spiral reinforcement 16. It is made of Q235B or Q335B steel, in the form of a 200mm×200mm×10mm square steel plate, with a pre-drilled hole in the center. The diameter of the hole is adjusted according to the diameter of the anchor rod 12, and must match the diameter of the anchor rod 12 so that the anchor rod 12 can pass freely through the pre-drilled hole. Specifically, the pad 4 is usually made of Q335B steel, and the diameter of the pre-drilled hole is 32mm.

[0051] It should also be noted that the spiral rib 16 uses HRB400 (grade III threaded steel) spiral ribs with a diameter of 10mm and a spiral rib spacing of 50mm.

[0052] The prestressed anti-buoyancy anchor structure provided in this embodiment uses large-diameter precision-rolled threaded steel for the anchor body, which has extremely high tensile strength. It can apply prestress over a wide range of stresses according to construction requirements. A prestressing cylinder is installed in the anchoring section, which effectively improves the bearing capacity of the grout and increases the prestress application range of the anti-buoyancy anchor. A spiral reinforcement is installed on the top side of the anchor body, which acts as a stirrup after the foundation slab is poured, effectively increasing the contact area between the anchor body and the foundation slab. This greatly improves the anchoring strength between the anchor body and the foundation slab, reduces slippage deformation between the foundation slab and the anchor body, enhances the integrity and structure of the anti-buoyancy anchor, and effectively reduces prestress loss.

[0053] Example 2 This embodiment provides a construction method for a large-diameter precision-rolled threaded steel prestressed anti-buoyancy anchor rod, which adopts the large-diameter precision-rolled threaded steel prestressed anti-buoyancy anchor rod structure described in Embodiment 1.

[0054] Specifically, the construction methods include the following: Apply epoxy anti-corrosion coating to the anchor rod body 12 and let it stand for a period of time until the epoxy anti-corrosion coating solidifies to form anti-corrosion coating 13. refer to Figure 3 and Figure 4 As shown, the centering device 1 is rotated and installed to the set position of the anchor rod 12 to ensure that the anchor rod 12 is located in the center of the anchor hole 14 during installation and does not shift. The anchor rod is lowered into the anchor hole 14. When the centering device is close to the opening of the anchor hole, a positioning component is placed on the surface of the concrete pad 11. The anchor rod is lowered further. When the centering device contacts the positioning component, the lowering of the anchor rod 12 is stopped to ensure that the length of the part of the anchor rod 12 placed in the anchor hole 14 is constant and the anchor rod 12 is located in the center of the anchor hole 14. The grouting pipe 17 is placed in the anchor hole. The grouting pipe 17 is located on the side of the anchor rod body 12. Grout is injected into the anchor hole 14 through the grouting pipe to form the grouting body 15. The grouting is completed when the grouting body 15 fills the anchor hole. Remove the positioning components and place the water-swellable rubber waterstop strip 9 around the anchor hole 14. The diameter of the ring formed by the water-swellable rubber waterstop strip 9 is 5mm-15mm larger than the diameter of the anchor hole 14. In this embodiment, the diameter of the anchor hole 14 is 150mm and the diameter of the ring formed by the water-swellable rubber waterstop strip 9 is 160mm. Fit the prestressed cylinder 8 onto the anchor rod body 12 and insert the cylinder into the anchor hole. The bearing member is located above the concrete pad 11, so that the bottom surface of the bearing member is in contact with the concrete pad 11 as much as possible. The gap between the bottom surface of the bearing member and the concrete pad 11 is filled by the water-swellable rubber waterstop strip 9. Place the first nut 7 on the anchor rod body 12 above the bearing member to ensure that the anchor rod body 12 does not deviate from its position. The grouting pipe passes through the pressure-bearing component and re-enters the anchor hole 14 to perform secondary grouting on the anchor hole 14. The secondary grouting adopts pressure grouting, which can eliminate voids, remove excess air bubbles, and make the grout body dense. It ensures that the grout body 15 reaches or exceeds the design strength of the grout after solidification. After the grout body in the anchor hole 14 is completely dense, excess air bubbles are removed, and voids are eliminated, the secondary grouting ends. Then, the grouting pipe 17 is pulled out from the second hole of the pressure-bearing component. A waterproof layer 10 is laid on the surface of the concrete cushion layer 11. After the secondary grouting has solidified, refer to... Figure 1 As shown, the bearing beam 6, jack 5, pad 4 and second nut 3 are sequentially fitted onto the anchor rod body 12. The jack 5 is started to apply prestress to the anchor rod body. The applied prestress is generally 5~20t. After the prestress is applied, the applied prestress is locked by the first nut. After the prestress of the anchor rod body is applied and locked, water is sprayed between the bearing component and the concrete pad, causing the water-swellable rubber waterstop to expand and completely fill the gap between the bearing component 8-1 and the concrete pad 11, thereby achieving a waterproof effect and playing a certain role in positioning and fixing. After locking, remove the second nut 3, pad 4, jack 5, and bearing beam 6. Place the spiral reinforcement 16 on top of the anchor rod body 12, compress and lock the spiral reinforcement 16 using the second nut, then place the pad 4 on top of the spiral reinforcement 16 and fix it with the second nut 3, compressing it slightly (50mm) to ensure the spiral reinforcement 16 is vertically fixed to the end of the anchor rod body 12. After the basement foundation slab is poured, the spiral reinforcement 16 acts as a stirrup, effectively increasing the contact area between the anchor rod body 12 and the foundation slab, greatly improving the anchoring strength between the anchor rod body 12 and the foundation slab, reducing slippage deformation between the foundation slab and the anti-buoyancy anchor, enhancing the integrity and structure of the anti-buoyancy anchor, and reducing the prestress loss of the anti-buoyancy anchor.

[0055] Among them, the jack 5 is a hand-held hydraulic through-hole jack. Compared with ordinary jacks, it has a more convenient and flexible working state. It also has the advantages of high strength, light weight and easy operation. It can accurately control the applied load. When applying prestress, it is placed above the bearing beam 6 and the bearing beam 6 is used to apply prestress to the anchor rod 12.

[0056] In some examples, the bearing beam 6 is made of Q335B steel, with a bearing thickness of 60 mm and a length of ≥300 mm. A hole is reserved in the middle, and the diameter of the hole is large enough to allow the anchor rod 12 to pass through freely. When prestressing is applied, it is placed below the jack 5 to bear the reaction force generated when prestressing is applied.

[0057] refer to Figure 8 and Figure 9 As shown, the centering device 1 includes a centering device cylinder 1-1 with a set length. The centering device cylinder 1-1 is specifically a centering device cylinder. A support plate 1-2 with a diameter larger than the diameter of the centering device cylinder 1-1 is provided at the bottom of the centering device cylinder 1-1. The support plate 1-2 is specifically a circular iron sheet. A reinforcing rib 1-4 is provided between the support plate 1-2 and the centering device cylinder 1-1. Several grooves 1-3 are provided circumferentially on the support plate 1-2. Specifically, four arc-shaped grooves are evenly distributed to prevent the anchor rod from rolling when it is laid horizontally on the ground. The centering device cylinder is made of Q335B steel, and the wall thickness of the centering device cylinder 1-1 is 5mm. The centering device cylinder is coupled with the anchor rod 12 in diameter. The centering device cylinder 1-1 has threads on the inside, so that the inner surface of the centering device cylinder 1-1 is connected and fixed to the anchor rod 12 by threads. The diameter of the reserved hole in the support plate 1-2 is the same as the inner diameter of the centering device cylinder 1-1. Specifically, the whole is made of Q235B or Q335B steel. The diameter of the reserved hole between the inner diameter of the centering device cylinder 1-1 and the support plate 1-2 is 32mm~40mm, and the wall thickness can be between 3mm~5mm.

[0058] It should be noted that, for reference Figure 10 As shown, the positioning component is specifically a positioning tripod 2. The outline of the positioning tripod 2 is an obtuse isosceles triangle. The base of the positioning tripod is provided with an opening for installation. The side length of the opening is greater than the diameter of the anchor rod body and less than the side length or diameter of the centering device support plate. The positioning component allows the anchor rod body to pass through but prevents the centering device from passing through, thereby achieving the positioning function and fixing the anchoring length.

[0059] The longitudinal section of the pressure beam is portal-shaped, and the inner diameter or side length of the lower half of the pressure beam is greater than the side length or inner diameter of the pressure member. In addition, before the centering device is installed on the anchor rod body, an anti-corrosion coating 13 is applied to the circumferential direction of the anchor rod body. The anti-corrosion coating 13 uses epoxy anti-corrosion paint, which has good chemical resistance. It can resist the corrosion of chemicals such as acids, alkalis, and salts, protect the metal surface from chemical corrosion, and the adhesion between the formed anti-corrosion coating 13 and the metal surface is very strong, which can effectively prevent the anti-corrosion coating 13 from falling off or peeling off.

[0060] The construction method provided in this embodiment enables the accurate lowering of the anchor rod length through the centering device and positioning components. After lowering, the anchor hole is grouted once, and then the prestressed cylinder 8 is installed. After the prestressed cylinder is installed, a second grouting is performed. After grouting, the prestressed cylinder and anchor rod are prestressed and locked using jacks. After locking, spiral reinforcement is installed on the outside of the exposed anchor hole of the anchor rod, which can effectively increase the contact area between the anchor rod and the subsequent basement foundation slab, and greatly improve the anchoring strength between the anchor rod and the foundation slab.

[0061] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A construction method for a large-diameter precision-rolled threaded steel prestressed anti-buoyancy anchor rod, characterized in that, A prestressed anti-buoyancy anchor bolt structure using large-diameter precision-rolled threaded steel includes the following components: Install the centering device to the set position of the anchor rod body, lower the anchor rod body into the anchor hole, and place the positioning component on the surface of the concrete pad when the centering device is close to the anchor hole opening. Continue to lower the anchor rod body, and stop lowering the anchor rod body when the centering device contacts the positioning component, so that the length of the anchor rod body entering the anchor hole is the set value. Place the grouting pipe into the anchor hole and inject grout into the anchor hole until the grouting body fills the anchor hole, thus ending one grouting cycle. Remove the positioning components, fit the prestressed sleeve onto the anchor rod body, insert the sleeve into the anchor hole, place the bearing component above the concrete pad, and place the first locking component on the anchor rod body above the bearing component; The grouting pipe passes through the pressure-bearing component and re-enters the anchor hole for secondary grouting. After the grout from the secondary grouting has solidified, the bearing beam, jack, and second locking device are sequentially fitted onto the anchor rod body. The jack is then activated to apply prestress to the anchor rod body. After the prestress is applied, the applied prestress is locked by the first locking device. After locking is completed, remove the second locking component, jack and bearing beam, put the spiral reinforcement on the top of the anchor rod, and compress and lock the spiral reinforcement through the second locking component; The large-diameter precision-rolled threaded steel prestressed anti-buoyancy anchor structure includes an anchor rod body made of precision-rolled threaded steel. The anchor rod body is a prestressed anchor rod body, which is inserted into an anchor hole. The top two sides of the anchor hole are concrete pads. The prestressed cylinder includes a bearing member and a cylinder body. The bearing member is located at the top of the cylinder body, and the cylinder body is located circumferentially around the anchor rod body. The anchor rod body extends beyond the bearing member. The bearing member is located above the concrete pads. The lower surface of the bearing member, located on the outside of the cylinder body, is sealed to the concrete pads. A first locking member is located on the surface of the bearing member to lock the anchor rod body. A spiral reinforcement is fitted onto the portion of the anchor rod body that extends beyond the first locking member to increase the contact area between the anchor rod body and the concrete layer. The spiral reinforcement is locked by a second locking member. The bearing member has a first hole in the middle for the anchor rod to pass through, and a second hole is also reserved on the side of the first hole to facilitate grouting; The length of the cylinder is greater than or equal to three times the diameter of the anchor hole, and the wall thickness of the cylinder is 3-5 mm; A water-swellable rubber waterstop strip is provided between the lower surface of the pressure-bearing component located on the outer side of the cylinder and the concrete pad layer. The water-swellable rubber waterstop strip is located in the circumferential direction of the cylinder.

2. The construction method of a large-diameter precision-rolled threaded steel prestressed anti-buoyancy anchor rod according to claim 1, characterized in that, The pressure-bearing component is a pressure-bearing plate, which is welded to the cylinder. The diameter or side length of the pressure-bearing plate is greater than the outer diameter of the cylinder. The outer diameter of the cylinder is less than or equal to the diameter of the anchor hole, and the side length or diameter of the pressure-bearing member is greater than the diameter of the anchor hole.

3. The construction method of a large-diameter precision-rolled threaded steel prestressed anti-buoyancy anchor rod according to claim 1, characterized in that, The first locking element is a first nut, and the second locking element is a second nut; A pad is provided between the second locking member and the spiral rib.

4. The construction method of a large-diameter precision-rolled threaded steel prestressed anti-buoyancy anchor rod according to claim 1, characterized in that, The centering device includes a centering device cylinder of a set length. The inner surface of the centering device cylinder is connected and fixed to the anchor rod body by threads. A support plate is provided at the bottom of the centering device cylinder, and reinforcing ribs are provided between the support plate and the centering device cylinder. Several grooves are provided in the circumferential direction of the support plate.

5. The construction method of a large-diameter precision-rolled threaded steel prestressed anti-buoyancy anchor rod according to claim 1, characterized in that, After the positioning component is removed, a water-swellable rubber waterstop strip is placed around the anchor hole opening. After the prestressing of the anchor rod body is applied and locked, water is sprayed between the bearing component and the concrete pad to cause the water-swellable rubber waterstop strip to expand. The positioning component has an isosceles triangle outline, and an opening is provided on the bottom side of the positioning component for installation. The side length of the opening is greater than the diameter of the anchor rod body and less than the side length or diameter of the centering device support plate.

6. The construction method of a large-diameter precision-rolled threaded steel prestressed anti-buoyancy anchor rod according to claim 1, characterized in that, The longitudinal section of the pressure-bearing beam is portal-shaped, and the inner diameter or side length of the lower half of the pressure-bearing beam is greater than the side length or inner diameter of the pressure-bearing component. Before the centering device is installed on the anchor rod body, the anchor rod body is coated with an anti-corrosion coating in the circumferential direction. The secondary grouting is performed using pressure grouting.

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