Prestressed anti-floating anchor rod structure and construction method

Abstract

The invention belongs to the technical field of building anti-floating construction, and particularly discloses a prestress anti-floating anchor rod structure and a construction method.The structure comprises an anchor rod body, a first base plate, a second base plate, a sleeve, a water swelling sealing ring and an anchoring body; a plurality of layers of composite waterproof anticorrosive coatings are arranged on the outer surface of the anchor rod body and are tightly arranged on the outer side of the anchor rod body in cooperation with the sleeve and the anchoring body, multiple physical and chemical protection barriers are formed, moisture, oxygen and corrosive media in the external environment are effectively prevented from permeating to the surfaces of steel bars, and therefore the service life of the anchor rod is greatly prolonged; besides, waterproof coatings are arranged on the opposite sides of the first base plate and the second base plate, and a water swelling sealing ring arranged between the first base plate and the second base plate is combined, so that a stepped waterproof sealing system is formed, dynamic self-adaptive sealing is achieved, and the interface sealing performance between the prestress anti-floating anchor rod structure and a basement bottom plate is remarkably enhanced; and the waterproof integrity and the use function of the basement structure are practically guaranteed.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of building anti-floating construction, and more particularly relates to a prestressed anti-floating anchor rod structure and a construction method. BACKGROUND

[0002] In the field of underground engineering, especially in areas with high underground water level, underground structures such as basements, underground garages, underground pipe galleries and the like are long-term threatened by the uplift force of underground water. When the self-weight of the structure is insufficient to resist the uplift force generated by the underground water, the structure may be uplifted, cracked or even destabilized as a whole, which seriously affects the safety and service life of the project. Therefore, anti-floating design is a key link in the design of underground structures. In traditional anti-floating measures, anti-floating anchor rods are widely used due to their convenient construction, moderate cost and strong adaptability. The basic principle is to anchor one end of the anchor rod to the stable stratum and connect the other end to the basement floor, and to resist the uplift force of underground water by the interfacial friction between the anchor rod body and the surrounding soil. However, this passive force mechanism has inherent limitations: the development of anti-floating force depends on a certain amount of uplift displacement of the structure to stimulate the friction between the anchor rod and the soil, which leads to unacceptable uplift deformation of the structure under large uplift force conditions, making it difficult to meet the needs of precision facilities or important buildings with strict deformation control requirements. In order to meet the design anti-floating force requirements, the density and length of the anchor rod often need to be increased significantly, which not only significantly increases the consumption of materials such as steel and increases the engineering cost, but also the dense arrangement of anchor rods may interfere with the arrangement of pipelines, equipment foundations and the like in the floor slab, affecting the space utilization function of the basement and subsequent use.

[0003] To solve the problem of weak anti-floating effect and poor deformation control ability of traditional anti-floating anchor rods, the existing technology further develops prestressed anti-floating anchor rod technology. This technology pre-applies a certain prestress (usually by using tensioning equipment to tension and lock the anchor rod body) during installation of the anchor rod, so that the anchor rod is in tension before bearing the uplift force of underground water, forming an active constraint on the underground structure. Through the pre-applied prestress, the technology can effectively offset part of the uplift force of underground water, reduce the uplift deformation of the structure under the action of the uplift force, and actively limit the displacement of the structure, improving the overall stability of the structure. At present, the prestressed anti-floating anchor rod technology has been gradually applied to underground engineering with medium to high water level, large uplift force or certain requirements for deformation control, such as large commercial complex basements, underground rail transit supporting structures, etc., trying to make up for the technical shortcomings of traditional anti-floating anchor rods through an active anti-floating mechanism.

[0004] Although the prestressed anti-floating anchor in the prior art has a significant improvement in the anti-floating effect and deformation control compared with the traditional anti-floating anchor, when applied to the basement floor structure anti-floating scene, there are still some technical defects, which cannot completely meet the long-term safety and functional requirements of the basement floor structure, such as: the steel body of the existing prestressed anti-floating anchor is directly in contact with the anchoring body and underground water, although some technologies will brush a corrosion-resistant coating on the surface of the steel body, but the coating is easy to be damaged due to collision and friction during construction, and after the anchoring body cracks, the corrosive medium such as chloride ion and sulfate in the underground water and soil will penetrate to the surface of the steel body through the cracks, destroy the passivation film on the surface of the steel, and cause the steel to rust; the rusting of the steel body will cause the cross-sectional area of the steel to decrease and the mechanical properties to decrease, not only reducing the anti-floating bearing capacity of the anchor, but also further expanding the cracks of the anchoring body due to the volume expansion of the rusting products, forming a vicious cycle of "cracking-rusting-further cracking", and eventually leading to the failure of the anchor; in addition, the connection part of the existing prestressed anti-floating anchor and the floor usually adopts a simple sealing glue plugging or a coiled material waterproof covering method, but after the anchoring body cracks and / or the steel body corrodes, the underground water will penetrate to the connection interface of the anchor and the floor along the cracks, break through the existing waterproof measures, and cause the floor to leak; the waterproof failure of the floor will not only affect the normal use function of the underground space, but also aggravate the rusting of the steel body and the carbonization of the structure concrete, and shorten the service life of the underground structure. SUMMARY

[0005] In view of the above defects or improvement needs of the prior art, the present application provides a prestressed anti-floating anchor structure and a construction method, which realizes the high unification of anti-floating function and waterproof durability through the synergistic effect of multi-layer protection and multi-seal mechanism, is suitable for underground engineering with strict requirements on deformation control and waterproof, and has good application prospect and popularization value.

[0006] In order to achieve the above-mentioned purpose, the present application provides a prestressed anti-floating anchor structure, which comprises: an anchor body, a first backing plate, a second backing plate, a sleeve, a water-swelling waterstop ring and an anchoring body; wherein: The first backing plate is a reinforced concrete structure, which is arranged at the upper end of the anchor hole and embedded at the bottom end of the basement floor; the middle part of the first backing plate is provided with a through hole matched with the anchor hole, and the upper surface is coated with a waterproof coating; One end of the anchor body is arranged in the anchor hole, and the other end penetrates through the first backing plate arranged at the upper end of the anchor hole; the outer surface of the anchor body is provided with a corrosion-resistant coating, which comprises, from outside to inside: a hot-dip galvanized layer or an epoxy coating, a two-component polyurethane corrosion-resistant coating, and a microcapsule self-repairing coating; The sleeve is sleeved outside the anchor body, and the inner wall of the sleeve is tightly attached to the outer surface of the anchor body; The anchor body is filled with a solidified cement slurry in the gap between the anchor rod body and the anchor hole, the anchor rod body and the first backing plate, for transmitting the anchor rod tension to the surrounding rock mass, while sealing the gap and preventing moisture intrusion; The water-swelling sealing ring is arranged outside the anchor rod body and is arranged on the upper end of the first backing plate. The second backing plate is arranged outside the anchor rod body, the bottom end surface of the second backing plate is coated with a waterproof coating and is pressed on the upper end of the water-swelling sealing ring, and the second backing plate and the anchor rod body are locked by a threaded fastening nut, for maintaining the stability of the prestress value after the prestress tension of the anchor rod body is completed.

[0007] Further, the prestressed anti-floating anchor rod structure further comprises a third backing plate, the third backing plate is fixedly arranged outside the anchor rod body, and the third backing plate is arranged above the second backing plate and is embedded in the basement floor.

[0008] Further, the first backing plate is a high-strength reinforced concrete structure, and a plurality of first steel joint connectors are vertically embedded and exposed on the upper end of the first backing plate. A plurality of through holes are uniformly arranged on the third backing plate, and a second steel joint connector is vertically embedded in each through hole; the outer side of each second steel joint connector is fixedly connected to the third backing plate through a plurality of rib plates; and the second steel joint connector corresponds to the first steel joint connector.

[0009] Further, the microcapsule type self-repairing coating comprises: epoxy resin microcapsules and silane microcapsules.

[0010] Further, a groove adapted to the water-swelling sealing ring is arranged in the middle of the upper end of the first backing plate, and the height of the groove is less than the thickness of the water-swelling sealing ring.

[0011] Further, the sleeve is a heat-shrinkable plastic sleeve. The upper end of the sleeve is in contact with the bottom end of the first backing plate, and the length of the sleeve is the same as the thickness of the soil layer below the first backing plate.

[0012] Further, the anchor rod body further comprises: an enlarged head, the enlarged head is fixedly arranged at the bottom end of the anchor rod body and is adapted to an enlarged chamber formed by high-pressure jet grouting during the hole forming stage. The enlarged head is expanded under stress in the enlarged chamber, so that the outer wall of the enlarged head abuts against the hole wall of the enlarged chamber and forms a mechanical self-locking structure, for increasing the effective contact area and frictional resistance between the bottom of the anchor rod and the rock mass.

[0013] The present application further provides a construction method of the prestressed anti-floating anchor rod structure, which is applied to the prestressed anti-floating anchor rod structure as described above and comprises the following steps: S1: excavate to the base, determine the anchor rod position, drill a hole to the specified depth using a drilling machine, remove the remaining residue in the hole, complete the anchor hole construction, clean the floating slurry and level it, then set the first pad plate on the anchor hole, and pour the concrete bottom pad layer on the base; S2: after the sleeve is sleeved on the corresponding position of the anchor rod body, the anchor rod body is put into the anchor hole from the corresponding through hole of the first pad plate until the bottom end of the anchor rod body is in close contact with the hole wall of the anchor hole and forms a mechanical self-locking structure; S3: cement slurry is injected from the anchor hole to the upper surface of the first pad plate through the guide pipe, and the sleeve is set on the first pad plate to superfill the cement slurry by 500-600 mm in height, and after the slurry reaches the design strength to form an anchoring body, the superfilled part is chiseled off; S4: after the water-swelling water stop ring, the second pad plate and the corresponding fastening nut are sleeved on the anchor rod body, the anchor rod body is subjected to tension by the tensioning equipment, and when the preset tension is reached, the second pad plate is locked by the fastening nut, then the third pad plate is sleeved on the anchor rod body and locked by the nut, and the construction of the prestressed anti-floating anchor rod structure is completed.

[0014] Further, the first pad plate is a prefabricated modular pad plate.

[0015] Further, in the step, plastic film and / or geotextile are laid on the first pad plate before grouting.

[0016] Overall, compared with the prior art, the above technical solutions conceived by the present application can achieve the following beneficial effects: 1. The prestressed anti-floating anchor rod structure of the present application realizes the high unification of anti-floating function and water durability through the synergistic effect of multi-layer protection and multi-water stop mechanism, is suitable for underground engineering with strict requirements on deformation control and water resistance, sets multi-layer composite waterproof and anticorrosive coating on the outer surface of the anchor rod body, cooperates with the sleeve and the anchoring body closely arranged on the outside of the anchor rod body to form a multi-layer physical and chemical protection barrier, effectively blocks the penetration of moisture, oxygen and corrosive medium in the external environment to the surface of the reinforcing steel bar, significantly improves the corrosion resistance of the anchor rod body, and thus greatly prolongs the service life thereof; in addition, a waterproof coating is arranged on the opposite side of the first pad plate and the second pad plate, and a water-swelling water stop ring is arranged therebetween to form a stepped waterproof sealing system, realize dynamic self-adaptive sealing, significantly enhance the interface sealing performance between the prestressed anti-floating anchor rod structure and the basement bottom plate, effectively prevent groundwater from seeping into the indoor area along the anchor rod channel, and effectively guarantee the waterproof integrity and use function of the basement structure.

[0017] 2. The prestressed anti-floating anchor rod structure of the present application, by setting the sleeve as a heat-shrinkable plastic sleeve, thereby realizing close fitting and fixing with the outer surface of the anchor rod body through the radial shrinkage force generated after heating, relying on the physical shrinkage mechanism to complete the installation, without the use of adhesive, effectively avoiding the durability problems such as loosening and falling off of the sleeve caused by aging, cracking or bonding failure of the adhesive, significantly improving the long-term stability and reliability of the protective structure; at the same time, the heat-shrinkable installation method is simple in process and convenient to operate, which can significantly shorten the on-site construction period, reduce the construction difficulty and labor cost, and is beneficial to improve the overall construction efficiency, having good economy and engineering applicability.

[0018] 3. The prestressed anti-floating anchor rod structure of the present application, by corresponding the second steel joint to the first steel joint, thereby facilitating precise alignment and reliable connection of the upper and lower steel bars during construction, ensuring that the anchor rod structure and the steel bar mesh in the basement floor form a continuous and unified stress system, thereby effectively improving the structural integrity and collaborative working capacity, facilitating efficient load transfer, enhancing the crack resistance and stability of the anchoring area, and ensuring the long-term safety and durability of the anti-floating system.

[0019] 4. The prestressed anti-floating anchor rod structure of the present application, by setting the enlarged head, thereby increasing the effective contact area and frictional resistance between the anchor rod bottom and the rock mass, greatly improving the overall anchoring force and uplift resistance of the anchor rod, at the same time, the self-locking mechanism effectively prevents the anchor rod body 4 from retracting or loosening under the action of long-term prestress or repeated action of uplift load, ensuring the stable transmission of prestress; in addition, the close fitting of the enlarged head 401 and the enlarged chamber helps to maintain the verticality of the anchor rod body 4 in the anchor hole 3, avoiding stress concentration or uneven grouting due to deflection, improving construction accuracy and structural reliability. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 is a structural schematic diagram of the prestressed anti-floating anchor rod structure of the embodiment of the present application; Figure 2 is a structural schematic diagram at embodiment A of the present application; Figure 3 is a step flow schematic diagram of the construction method of the prestressed anti-floating anchor rod structure of the embodiment of the present application.

[0021] In all the drawings, the same reference signs represent the same technical features, specifically: 1 - basement floor, 2 - floor pad, 3 - anchor hole, 4 - anchor rod body, 401 - enlarged head, 5 - first pad, 501 - first steel joint, 6 - second pad, 7 - third pad, 701 - second steel joint, 8 - sleeve, 9 - water-swelling water-stop ring, 10 - anchoring body. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical scheme and advantages of the present application more clear, the present application is further described in detail below with reference to the drawings and examples. It should be understood that the specific examples described herein are only used to explain the present application and not to limit the present application. In addition, the technical features involved in the various embodiments of the present application described below can be combined with each other as long as they do not conflict with each other.

[0023] Please refer to Figure 1 and Figure 2 , the present application provides a prestressed anti-floating anchor rod structure, comprising: anchor rod body 4, first pad plate 5, second pad plate 6, sleeve 8, water-swelling water stop ring 9 and anchoring body 10; wherein: The first pad plate 5 is a reinforced concrete structure, which is arranged on the upper end of the anchor hole 3 and buried in the bottom end of the basement floor 1; the middle part of the first pad plate 5 is provided with a through hole matched with the anchor hole 3 and the upper surface is coated with a waterproof coating; The anchor rod body 4 is arranged at one end of the anchor hole 3, and the other end passes through the first pad plate 5 arranged at the upper end of the anchor hole 3; the outer surface of the anchor rod body 4 is provided with a corrosion-resistant coating, which includes, from the outside to the inside, a hot-dip galvanized layer or an epoxy coating, a two-component polyurethane corrosion-resistant coating, and a microcapsule self-repairing coating; The sleeve 8 is sleeved on the outer side of the anchor rod body 4, and the inner wall thereof is tightly attached to the outer surface of the anchor rod body 4; The anchoring body 10 is a solidified cement slurry filled in the gap between the anchor rod body 4 and the anchor hole 3, and the gap between the anchor rod body 4 and the first pad plate 5, which is used to transmit the anchor rod tension to the surrounding rock mass and simultaneously seal the gap to prevent water from entering; The water-swelling water stop ring 9 is sleeved on the outer side of the anchor rod body 4, and is arranged on the upper end of the first pad plate 5; The second pad plate 6 is sleeved on the outer side of the anchor rod body 4, and the bottom end surface thereof is coated with a waterproof coating and is pressed on the upper end of the water-swelling water stop ring 9; the second pad plate 6 and the anchor rod body 4 are locked by a threaded fastening nut, which is used to keep the prestress value stable after the prestress tension of the anchor rod body 4 is completed.

[0024] It can be understood that the prestressed anti-floating anchor rod structure of the application realizes the high unification of anti-floating function and waterproof durability through the synergistic effect of multi-layer protection and multiple water stop mechanisms, is suitable for underground engineering with strict requirements on deformation control and waterproof, and has good application prospect and popularization value; wherein, by setting a multi-layer composite waterproof and anticorrosive coating on the outer surface of the anchor rod body 4, and cooperating with the sleeve 8 and the anchoring body 10 closely arranged outside the anchor rod body 4, a multiple physical and chemical protection barrier is formed, effectively preventing the penetration of moisture, oxygen and corrosive medium in the external environment to the surface of the steel bar, significantly improving the corrosion resistance of the anchor rod body 4, thereby greatly prolonging the service life thereof; in addition, by setting a waterproof coating on the opposite side of the first and second pads 5 and 6, and combining the water-swelling water stop ring 9 arranged therebetween, a stepped waterproof sealing system is formed, dynamic self-adaptive sealing is realized, the interface sealing performance between the prestressed anti-floating anchor rod structure and the basement floor 1 is significantly enhanced, and the infiltration of groundwater along the anchor rod channel into the indoor is effectively prevented, thereby effectively guaranteeing the waterproof integrity and use function of the basement structure.

[0025] In an optional embodiment, the anchor rod body 4 is a JL32 type finished rolled threaded steel bar, and the diameter is 32mm to 35mm, which is used as the core stress bearing member of the anchor body to ensure the overall bearing capacity.

[0026] In an optional embodiment, the microcapsule type self-repairing coating includes epoxy resin microcapsules and silane microcapsules, which are suitable for environments with abundant groundwater and high humidity to reduce the corrosion probability of the anchor rod body 4.

[0027] In an optional embodiment, a groove matched with the water-swelling water stop ring 9 is arranged in the middle of the upper end of the first pad 5, and the height of the groove is less than the thickness of the water-swelling water stop ring 9, which is used to effectively limit the water stop ring to prevent its deviation or pressure deformation, form a reliable water-tight seal, significantly improve the waterproof performance, and eliminate the leakage risk.

[0028] In an optional embodiment, the sleeve 8 is a heat-shrinkable plastic sleeve, which is tightly fitted and fixed to the outer surface of the anchor rod body 4 through the radial shrinkage force generated after heating, and relies on the physical shrinkage mechanism to complete the installation without using adhesive, thereby effectively avoiding the durability problems such as loosening and falling off of the sleeve caused by aging, cracking or bonding failure of the adhesive, and significantly improving the long-term stability and reliability of the protection structure; at the same time, the heat-shrinkable installation method is simple in process and convenient to operate, which can significantly shorten the on-site construction period, reduce the construction difficulty and labor cost, is conducive to improving the overall construction efficiency, has good economy and engineering applicability.

[0029] In an optional embodiment, the upper end of the sleeve 8 is in contact with the bottom end of the first pad plate 5, and the length of the sleeve 8 is the same as the thickness of the soil layer below the first pad plate 5. It can be understood that the area where the sleeve 8 is located is the free section of the prestressed anti-floating anchor, which is the part that does not generate friction with the surrounding soil to provide anchoring force, and its main role is to be able to freely stretch and contract when the anchor is prestressed, effectively transmitting the tension to the anchoring section, and then transmitting the tension to the surrounding stable soil through the anchoring section provided in the rock layer.

[0030] In an optional embodiment, the waterproof coating is prepared from a cement-based capillary crystalline waterproof coating, which is used to form insoluble crystals, effectively block capillary channels and micro cracks, significantly improve the impermeability and self-healing ability of the interface area, enhance the overall waterproof sealing between the prestressed anti-floating anchor structure and the basement floor 1, and long-term guarantee the structural durability and safety in use.

[0031] In an optional embodiment, the first pad plate 5 is a high-strength reinforced concrete structure, and the upper end of the first pad plate 5 is vertically embedded and exposed with a plurality of first steel bar joints 501, which are used to realize reliable connection with the waterproof concrete structure of the basement floor 1, effectively transmit stress and coordinate deformation, enhance the integrity and crack resistance of the node area, and at the same time, it is beneficial to improve the structural continuity of the concrete of the basement floor 1, inhibit the development of cracks caused by local stress concentration, and thus guarantee the impermeability and durability of the basement floor 1 under long-term water pressure.

[0032] In an optional embodiment, the cement paste is prepared from a cement-based inorganic grouting material, and the strength grade is C50, which is used to form a dense and solid anchoring body 10, thereby significantly improving the bonding performance and bearing capacity of the anchoring interface, ensuring reliable transmission of prestress, enhancing the overall stability and long-term durability of the anchor, and meeting the requirements of high-performance materials for anti-floating structures.

[0033] Please refer to Figure 1 and Figure 2 , the prestressed anti-floating anchor structure further comprises a third pad plate 7, the third pad plate 7 is fixedly sleeved outside the anchor body 4, which is arranged above the second pad plate 6 and embedded in the basement floor 1, so as to effectively enhance the stiffness and bending resistance of the anchoring area, uniformly diffuse and transmit the concentrated load from the anchor to the surrounding floor concrete, reduce local stress concentration, improve the overall stress performance of the structure and the stability of the anchor connection node, ensure reliable transmission of anti-floating force, and guarantee the safety of the floor structure.

[0034] In the optional embodiment, the third cushion plate 7 is uniformly provided with a plurality of through holes, and a second steel bar joint 701 is vertically embedded in each through hole to reliably connect with the internal steel bar mesh of the basement floor 1, form an integral stress system, effectively enhance the anchoring performance and synergistic working capacity between the third cushion plate 7 and the floor concrete, improve the stiffness and stability of the anchoring node, facilitate the uniform transmission of concentrated load, prevent local cracking, and ensure the structural integrity and long-term durability.

[0035] In the optional embodiment, the outer side of each second steel bar joint 701 is fixedly connected with the third cushion plate 7 through a plurality of rib plates to enhance the connection stiffness and integrity between the steel bar joint and the cushion plate, effectively transmit shear force and tension, and prevent the joint from loosening or pulling out.

[0036] In the optional embodiment, the second steel bar joint 701 corresponds to the first steel bar joint 501, so as to facilitate the accurate alignment and reliable connection of the upper and lower steel bars during construction, ensure that the anchor rod structure and the steel bar mesh in the basement floor 1 form a continuous and unified stress system, effectively improve the structural integrity and synergistic working capacity, facilitate the efficient transmission of load, enhance the crack resistance and stability of the anchoring area, and ensure the long-term safety and durability of the anti-floating system.

[0037] Please refer to Figure 1 , the anchor rod body 4 further comprises: an enlarged head 401 fixedly arranged at the bottom end of the anchor rod body 4 and matched with an enlarged chamber formed by high-pressure jet grouting at the bottom of the anchor hole 3 during the hole forming stage; the enlarged head 401 is stressed and expanded in the enlarged chamber, so that the outer wall thereof abuts against the hole wall of the enlarged chamber and forms a mechanical self-locking structure, which is used to increase the effective contact area and frictional resistance between the bottom of the anchor rod and the rock mass, greatly improve the overall anchoring force and anti-pulling performance of the anchor rod, and simultaneously, the self-locking mechanism effectively prevents the anchor rod body 4 from retracting or loosening under the repeated action of long-term prestress or upward load, ensures the persistent and stable transmission of the prestress; in addition, the close fit of the enlarged head 401 and the enlarged chamber helps to maintain the verticality of the anchor rod body 4 in the anchor hole 3, avoids stress concentration or uneven grouting due to deflection, improves the construction precision and structural reliability.

[0038] It should be noted that the enlarged head in the embodiment is a common anchor head component in the prior art, such as a reverse conical multi-petal enlarged head or a reverse conical multi-petal internal anchor head, and other types of anchor head components can also be used in other embodiments, as long as they can be stressed and expanded in the enlarged chamber, and the outer wall thereof abuts against the hole wall of the enlarged chamber and forms a mechanical self-locking structure, which is not specifically limited here.

[0039] Please refer to Figure 3 , the second aspect of the present application provides a construction method of a prestressed anti-floating anchor rod structure, comprising the following steps: S1: excavate to the base, determine the anchor rod position, drill a hole to the specified depth using a drill, remove the remaining residue in the hole, complete the anchor hole 3 construction, clean the floating slurry and level, set the first pad plate 5 on the anchor hole 3, and pour the concrete bottom plate cushion layer 2 on the base; S2: after the sleeve 8 is sleeved on the corresponding position of the anchor rod body 4, the anchor rod body 4 is put into the anchor hole 3 from the corresponding through hole of the first pad plate 5 to the bottom of the anchor rod body 4, and the outer wall of the enlarged head 401 provided at the bottom end of the anchor rod body 4 is in close contact with the hole wall of the anchor hole 3 and forms a mechanical self-locking structure; S3: cement slurry is injected from the anchor hole 3 to the upper surface of the first pad plate 5 through the pipe, and the sleeve is provided with 500-600mm of cement slurry, and after the slurry reaches the design strength to form the anchoring body 10, the overfilling part is removed; S4: after the water-swelling water stop ring 9, the second pad plate 6 and the corresponding fastening nut are sleeved on the anchor rod body 4, the anchor rod body 4 is subjected to tensioning force by the tensioning equipment, and when the preset tensioning force is reached, the second pad plate 6 is locked by the fastening nut, and then the third pad plate 7 is sleeved on the anchor rod body 4 and locked by the nut, thereby completing the construction of the prestressed anti-floating anchor rod structure.

[0040] In an optional embodiment, in step S1, an enlarged chamber is formed at the bottom of the anchor hole 3 by high-pressure jet grouting during the hole forming stage, and the enlarged chamber is matched with the enlarged head 401 provided at the bottom end of the anchor rod body 4.

[0041] In an optional embodiment, the first pad plate 5 is a prefabricated modular pad plate, which is used for rapid installation on site without cast-in-place construction on the bottom plate cushion layer 2, effectively avoiding disturbance and damage to the bottom plate cushion layer 2, and ensuring the integrity and waterproof performance thereof.

[0042] In an optional embodiment, in step S3, plastic film and / or geotextile are laid on the first pad plate 5 before grouting, so as to effectively isolate the grouting material from direct contact with the first pad plate 5 and the surrounding structure, prevent slurry leakage and flow from causing pollution, and avoid damage to the waterproof layer of the first pad plate 5 and the bottom plate cushion layer 2.

[0043] It should be noted that if the present application involves directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative positional relationship, movement condition, etc. between the components in a certain posture (as shown in the drawings), and if the certain posture changes, the directional indications will also change accordingly.

[0044] In addition, if the description of "first", "second" and the like is involved in the embodiments of the present application, the description of "first", "second" and the like is only for the purpose of description, and cannot be understood as indicating or implying the relative importance of the indicated technical features or implicitly indicating the number of the indicated technical features. Therefore, the features defined with "first", "second" can explicitly or implicitly include at least one of the features. In addition, the technical solutions of various embodiments can be combined with each other, but it must be based on the realization of the ordinary skilled in the art, when the combination of technical solutions appears contradictory or cannot be realized, it should be considered that the combination of technical solutions does not exist, nor within the protection scope required by the present application.

[0045] In the present application, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or apparatus including a series of elements includes not only those elements, but also other elements not explicitly listed, or further includes elements inherent to such process, method, article or apparatus. Without more limitations, the elements defined by the statement "comprising" do not exclude the presence of other identical elements in the process, method, article or apparatus including the elements.

[0046] Finally, it should be pointed out that: the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit it; those skilled in the art can easily understand that the above description is only the preferred embodiment of the present application, and is not used to limit the present application, any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A prestressed anti-buoyancy anchor structure, characterized in that, include: The anchor bolt body (4), the first pad (5), the second pad (6), the sleeve (8), the water-swellable sealing ring (9), and the anchor body (10); wherein: The first pad (5) is a reinforced concrete structure, which is located at the top of the anchor hole (3) and embedded at the bottom of the basement floor slab (1); the first pad (5) has a through hole in the middle that matches the anchor hole (3) and the upper surface is coated with a waterproof coating. One end of the anchor body (4) is located in the anchor hole (3), and the other end passes through the first pad (5) located at the upper end of the anchor hole (3); the outer surface of the anchor body (4) is provided with an anti-corrosion coating, which includes, from the outside to the inside, a hot-dip galvanized layer or an epoxy coating, a two-component polyurethane anti-corrosion coating, and a microcapsule self-healing coating. The sleeve (8) is fitted on the outside of the anchor body (4), and its inner wall is in close contact with the outer surface of the anchor body (4); The anchor body (10) is a solidified cement grout that fills the gap between the anchor body (4) and the anchor hole (3) and between the anchor body (4) and the first pad (5). It is used to transfer the anchor tension to the surrounding rock mass and at the same time seal the gap to prevent water intrusion. The water-swellable sealing ring (9) is sleeved on the outside of the anchor body (4) and is located on the upper end of the first pad (5); The second pad (6) is sleeved on the outside of the anchor body (4), and its bottom surface is coated with a waterproof coating and pressed on the upper end of the water-swellable sealing ring (9); the second pad (6) is locked to the anchor body (4) by a threaded fastening nut, which is used to keep the prestress value stable after the anchor body (4) has completed prestress tensioning.

2. The prestressed anti-buoyancy anchor structure according to claim 1, characterized in that, The prestressed anti-buoyancy anchor structure also includes a third pad (7), which is fixedly sleeved on the outside of the anchor body (4), and is located above the second pad (6) and embedded in the basement floor slab (1).

3. The prestressed anti-buoyancy anchor structure according to claim 2, characterized in that, The first pad (5) is a high-strength reinforced concrete structure, and multiple first steel bar joints (501) are vertically embedded and exposed at its upper end. The third pad (7) is provided with several through holes, and each through hole is vertically embedded with a second steel bar joint (701); the outer side of each second steel bar joint (701) is fixedly connected to the third pad (7) through several ribs; the second steel bar joint (701) corresponds one-to-one with the first steel bar joint (501).

4. The prestressed anti-buoyancy anchor structure according to any one of claims 1-3, characterized in that, The microcapsule-type self-healing coating includes: epoxy resin microcapsules and silane microcapsules.

5. The prestressed anti-buoyancy anchor structure according to any one of claims 1-3, characterized in that, The upper middle part of the first pad (5) is provided with a groove that is compatible with the water-swellable sealing ring (9), and the height of the groove is less than the thickness of the water-swellable sealing ring (9).

6. The prestressed anti-buoyancy anchor structure according to any one of claims 1-3, characterized in that, The sleeve (8) is a heat-shrinkable plastic sleeve; The upper end of the sleeve (8) contacts the bottom end of the first pad (5), and its length is the same as the thickness of the soil layer below the first pad (5).

7. The prestressed anti-buoyancy anchor structure according to any one of claims 1-3, characterized in that, The anchor body (4) also includes an enlarged head (401), which is fixedly disposed at the bottom end of the anchor body (4) and is adapted to the enlarged chamber formed by high-pressure jet grouting at the bottom of the anchor hole (3) during the hole-forming stage; The enlarged head (401) is enlarged by force in the enlarged chamber, so that its outer wall abuts against the hole wall of the enlarged chamber and forms a mechanical self-locking structure, which is used to increase the effective contact area and frictional resistance between the bottom of the anchor rod and the rock mass.

8. A construction method for a prestressed anti-buoyancy anchor structure, applied to the prestressed anti-buoyancy anchor structure as described in claims 1-7, characterized in that, Includes the following steps: S1: Excavate to the base, determine the anchor position, drill to the specified depth using a drilling rig, remove the remaining slag in the hole, complete the construction of the anchor hole (3), clean the laitance and level it, set the first pad (5) on the anchor hole (3), and pour the concrete base slab pad (2) on the base. S2: After the sleeve (8) is fitted onto the corresponding position of the anchor body (4), the anchor body (4) is inserted into the anchor hole (3) through the corresponding through hole of the first pad (5) until the anchor body (4) touches the bottom, and the outer wall of the enlarged head (401) provided at the bottom end of the anchor body (4) is tightly abutted against the hole wall of the anchor hole (3) to form a mechanical self-locking structure; S3: Cement grout is injected into the upper surface of the first pad (5) through the pipe through the anchor hole (3), and a sleeve is set on the first pad (5) to over-fill with cement grout to a height of 500mm to 600mm. After the grout reaches the design strength to form the anchor body (10), the over-filled part is removed. S4: After the water-swellable sealing ring (9), the second pad (6) and the corresponding fastening nut are fitted onto the anchor body (4), tension is applied to the anchor body (4) by tensioning equipment, and when the preset tension is reached, the second pad (6) is locked by fastening nut. Then, the third pad (7) is fitted onto the anchor body (4) and locked by nut to complete the construction of the prestressed anti-buoyancy anchor structure.

9. The construction method according to claim 8, characterized in that, The first pad (5) is a prefabricated modular pad.

10. The construction method according to claim 8, characterized in that, In step S3, after laying a plastic film and / or geotextile on the first pad (5), grouting is then carried out.

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