Anti-floating anchor rod and construction method thereof

Abstract

The application relates to the technical field of anti-floating of underground engineering, and provides an anti-floating anchor rod and a construction method thereof.The anti-floating anchor rod comprises a rod body, a framework and a grouting pipe.The rod body is formed by pouring concrete into a square columnar body; the framework is arranged and supported in the rod body; the grouting pipe is arranged on the rod body, one end of the grouting pipe extends to the bottom side of the rod body, and the other end of the grouting pipe extends to the outside of the top of the rod body, so that the grouting pipe is used for grouting after the anti-floating anchor rod is fixed; and a pre-buried pipe is pre-buried in the rod body, and the other end of the pre-buried pipe extends to the outside of the rod body.The anti-floating anchor rod provided by the application supports the framework in the rod body through the prefabricated square columnar rod body, the stability of the rod body structure is ensured, and deformation or collapse is avoided; meanwhile, the grouting pipe is arranged on the rod body, and the two ends of the grouting pipe extend to the bottom and the outside of the top respectively, so that the anchor rod can be implanted and fixed, and the grouting pipe can be used for implementing secondary grouting to the bottom after the anchor rod is implanted and fixed, the gap or the empty area between the rod body and the surrounding soil body is effectively filled, and the bonding force between the anchor rod and the surrounding soil body is significantly enhanced.

Description

Technical Field

[0001] This application relates to the field of anti-buoyancy technology in underground engineering, and in particular to an anti-buoyancy anchor and its construction method. Background Technology

[0002] Existing anti-buoyancy anchors mainly adopt cast-in-place or simple precast structures. Cast-in-place anchors require on-site drilling, reinforcement installation, grouting, and long-term curing, which involves complex procedures, long construction cycles, and is limited by site conditions and construction skills. The internal quality of the anchor is difficult to control, and defects such as incomplete grouting and reinforcement positioning deviations are prone to occur, resulting in unstable overall performance of the anchor.

[0003] Furthermore, after the initial grouting is completed, voids or gaps may appear in the grout during the solidification process due to shrinkage, groundwater erosion, or ground disturbance. This can easily lead to a decrease in the bond strength between the anchor and the soil, resulting in insufficient pull-out bearing capacity. After curing, it is difficult to perform supplementary grouting. If grouting defects are discovered or the anchoring effect needs to be enhanced, remedial measures such as surface drilling or adding anchors can only be taken, which are costly, time-consuming, and the effectiveness of the supplementary grouting is difficult to guarantee. Summary of the Invention

[0004] This application provides an anti-buoyancy anchor rod to solve the problems of low construction efficiency, complicated procedures, and difficulty in ensuring project quality of existing anti-buoyancy anchor rods, and also solves the grouting problem of existing anti-buoyancy anchor rods.

[0005] This application provides an anti-buoyancy anchor bolt, comprising: The pole is formed into a square column by pouring concrete. A skeleton, which is set and supported within the rod body; A grouting pipe is inserted through the rod body, with one end extending to the bottom side of the rod body and the other end extending to the top outside of the rod body, for grouting after the anti-buoyancy anchor is fixed; An embedded pipe is inserted into the rod body at one end and extends out of the rod body at the other end for connection with an external structure.

[0006] According to an anti-buoyancy anchor provided in this application, the anti-buoyancy anchor further includes: a first end cap and a second end cap; The first end cap is disposed at the top end of the rod, and the second end cap is disposed at the bottom end of the rod, so as to seal the frame at both ends of the rod for tensioning and locking. One end of the grouting pipe passes through the first end cap, passes through the rod body and extends to the bottom side of the rod body, and the other end of the grouting pipe extends to the outside of the top of the rod body; One end of the pre-embedded tube passes through the first end cap and is inserted into the rod body, while the other end of the pre-embedded tube extends to the outside of the first end cap for connection with an external structure.

[0007] According to an anti-buoyancy anchor provided in this application, the embedded pipe includes: an embedded sleeve and connecting steel bars; The pre-embedded sleeve is fixed at the first end cap and is entirely located within the rod body; one end of the connecting steel bar is assembled and connected to the pre-embedded sleeve, and the other end extends to the outside of the rod body as a joint for connection with the external structure.

[0008] According to the anti-buoyancy anchor provided in this application, the frame includes: multiple steel bars and multiple stirrups; Multiple reinforcing bars extend along the length of the rod, with both ends anchored to the first end cap and the second end cap respectively, and are in a prestressed tension state; multiple stirrups are sleeved on the outside of the multiple reinforcing bars and tied and fixed to each of the reinforcing bars.

[0009] According to the anti-buoyancy anchor provided in this application, the first end cap and the second end cap are anchor plates, and the two ends of the plurality of steel bars are directly locked to the first end cap and the second end cap respectively, so as to maintain the steel bars in a preset tension state.

[0010] According to the present application, an anti-buoyancy anchor rod has a square cross-section in the axial direction of the rod body.

[0011] According to the present application, an anti-buoyancy anchor rod is provided, wherein the rod body is filled with solidified concrete; the concrete encapsulates the skeleton, the portion of the grouting pipe located within the rod body, and the portion of the pre-embedded pipe located within the rod body into a single unit.

[0012] This application also provides a method for constructing an anti-buoyancy anchor, comprising the following steps: Anchor bolt holes are drilled at the construction site according to the geological conditions, and grout is injected into the anchor bolt holes once. Before initial setting, the pre-formed anti-buoyancy anchor is inserted into the bottom of the anchor hole, so that the filler material of the first grouting fully fills the gap between the anti-buoyancy anchor and the hole wall; After a predetermined time interval following the implantation of the anti-buoyancy anchor bolt, secondary grouting is performed to the bottom of the hole through the grouting pipe; The external extension end of the pre-embedded pipe is installed and connected to the external structure.

[0013] According to the construction method of the anti-buoyancy anchor provided in this application, the cross-section of the rod body in the axial direction is square, the drilling diameter of the anchor hole is 1.5-1.8 times the side length of the rod body, and the depth of the anchor hole is not less than the length of the anti-buoyancy anchor. The filler material for the primary grouting and / or the secondary grouting is cement grout, cement mortar, or fine aggregate concrete; the actual amount of filler material injected is not less than 1.2 times the theoretical calculation value, which is determined based on the diameter and depth of the anchor hole and the volume of the implanted anti-buoyancy anchor.

[0014] According to the construction method of the anti-buoyancy anchor provided in this application, in the secondary grouting and connection step, the predetermined time for secondary high-pressure grouting is 24 to 48 hours after the anchor is implanted; the termination condition for the secondary high-pressure grouting is the grouting pressure stabilizing for a preset time or the ground surface grouting.

[0015] The anti-buoyancy anchor provided in this application achieves structural stability by forming a square rod body through concrete pouring, supported by a framework within the rod body, thus preventing deformation or collapse. Simultaneously, a grouting pipe is inserted into the rod body, extending to the bottom and top outer sides respectively. This allows for secondary grouting to be performed at the bottom after the anchor is implanted and fixed, effectively filling gaps or voids created by the initial grouting, thereby significantly enhancing the bond between the anchor and the surrounding soil. Furthermore, the pre-embedded pipe provides a direct connection interface between the anchor and the external structure, eliminating the need for on-site rebar installation or welding, simplifying the construction process and improving connection reliability. In summary, this anti-buoyancy anchor effectively solves the technical problems of low construction efficiency, uncontrollable quality, difficulty in remedying grouting defects, and complex connections with external structures associated with existing anchors. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a cross-sectional schematic diagram of the anti-buoyancy anchor provided in this application.

[0018] Figure 2 yes Figure 1 A schematic diagram of section AA.

[0019] Figure 3 yes Figure 1 A schematic diagram of the BB section.

[0020] Figure 4 This is a flowchart illustrating the construction method of the anti-buoyancy anchor provided in this application.

[0021] Figure label: 1. Rod body; 2. Skeleton; 21. Reinforcing steel; 22. Stirrups; 3. Grouting pipe; 4. Embedded pipe; 41. Embedded sleeve; 42. Connecting reinforcing bars; 5. First end cap; 6. Second end cap. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0023] The following is combined with Figures 1-4 This application describes the anti-buoyancy anchor bolt and its construction method.

[0024] In some embodiments, such as Figures 1 to 3 As shown, the anti-buoyancy anchor bolt includes: a bolt body 1, a frame 2, a grouting pipe 3, and a pre-embedded pipe 4. The bolt body 1 is factory-cast in one piece. The frame 2 is installed inside the bolt body and forms an integral support, ensuring the structural stability of the bolt body 1 during transportation, hoisting, and installation, and preventing damage due to external tensile forces or soil pressure. The grouting pipe 3 passes through the bolt body 1, with one end extending to the outer bottom of the bolt body 1 and the other end extending to the outer top of the bolt body 1. This grouting pipe 3 is used for secondary grouting to the bottom of the hole after the anti-buoyancy anchor bolt is installed and fixed, to fill the gaps or voids formed by the primary grouting, and to enhance the bond between the anchor bolt and the surrounding soil. One end of the pre-embedded pipe 4 is inserted into the bolt body 1 and fixed by concrete, while the other end extends to the outer side of the bolt body 1 for connection to external structures (such as foundation slabs), thereby achieving reliable anchoring of the anchor bolt to the superstructure.

[0025] This anti-buoyancy anchor is manufactured using standardized prefabrication in a factory. First, a molding mold for the anchor body 1 is prepared according to the design dimensions. The pre-welded steel reinforcement frame 2, along with the first end cap 5 and the second end cap 6, is placed into the mold. Simultaneously, the grouting pipe 3 and the embedded pipe 4 are fixed in their designed positions. The grouting pipe 3 runs longitudinally through the anchor body 1, with both ends extending from the bottom and top of the mold, respectively. The embedded sleeve 41 of the embedded pipe 4 is fully inserted into the area of ​​the mold, flush with the top of the cap 5. Then, concrete is poured into the mold and vibrated to ensure compaction, so that the concrete encapsulates the frame 2, the grouting pipe 3, and the embedded pipe 4.

[0026] Afterward, the poured pole 1 will be cured until the concrete reaches its design strength. After curing, the formwork will be removed, and the surface of pole 1 will be inspected and repaired. Once it passes inspection, it will be numbered and stored, awaiting transport to the construction site.

[0027] The construction method for this anti-buoyancy anchor includes the following steps: First, the location and depth of the anchor bolt holes are determined at the construction site based on the geological survey report. The anchor bolt holes are formed by drilling rigs, and grouting is carried out into the anchor bolt holes. The first grouting usually uses cement mortar or cement paste. The grouting pressure and mix ratio are determined according to the design requirements to ensure the stability of the hole wall and provide initial anchoring force.

[0028] Secondly, before the initial setting of the grout, the prefabricated anti-buoyancy anchor rod is inserted into the bottom of the anchor hole. During the insertion process, the rod body 1 should be kept vertical and centered so that the grout can fully fill the gap between the anti-buoyancy anchor rod and the hole wall, expel excess air, and form a uniform coating layer.

[0029] Then, after the anti-buoyancy anchor bolts are implanted and a predetermined time interval has elapsed, generally after the initial grouting has fully set or reached a certain strength, a second grouting is performed through grouting pipe 3 towards the bottom of the hole. The second grouting can be performed using high-pressure grouting, which forces the grout into the voids or weak interlayers formed by the initial grouting, further compacting the anchoring section and improving its pull-out bearing capacity.

[0030] Finally, after the secondary grout reaches the design strength, the external extension end of the embedded pipe 4 is installed and connected to the external structure (such as the reserved steel bars or connectors in the foundation slab). The connection method can be mechanical connection, welding or threaded connection to ensure a clear and reliable force transmission path.

[0031] Through the above structure and construction method, the anti-buoyancy anchor rod achieves standardized prefabrication in the factory, rapid on-site installation, secondary grouting reinforcement after fixing, and convenient connection with external structures, effectively solving the technical problems of low construction efficiency, uncontrollable quality, and difficulty in remedying grouting defects of existing anchor rods.

[0032] The anti-buoyancy anchor provided in this application utilizes a frame 2 supported within the rod body 1 to ensure structural stability and prevent deformation or collapse. Simultaneously, a grouting pipe 3 is inserted through the rod body 1, extending to the bottom and top outer sides respectively. This allows for secondary grouting to be performed at the bottom after the anchor is implanted and fixed, effectively filling gaps or voids between the rod body and the surrounding soil, thus significantly enhancing the bond between the anchor and the surrounding soil. Furthermore, the pre-embedded pipe 4 provides a direct connection interface between the anchor and the external structure, eliminating the need for on-site rebar installation or welding, simplifying the construction process and improving connection reliability. In summary, this anti-buoyancy anchor effectively solves the technical problems of low construction efficiency, uncontrollable quality, difficulty in remedying grouting defects, and complex connections with external structures associated with existing anchors.

[0033] It should be noted that Rod 1 is entirely precast concrete. As the main structure of the anti-buoyancy anchor, Rod 1 is made of ordinary silicate concrete or high-performance concrete with a strength grade of not less than C30 to ensure sufficient compressive strength, impermeability, and durability. Rod 1 is cast in the factory in one go using molds, resulting in a complete overall structure without splicing seams or secondary construction interfaces, thus avoiding common quality defects such as honeycomb, pitting, and voids found in on-site casting. The external dimensions of Rod 1 are controlled by the molds, ensuring the geometric consistency of each anchor.

[0034] In some embodiments, such as Figure 1 As shown, the anti-buoyancy anchor also includes: a first end cap 5 and a second end cap 6. The first end cap 5 is located at the top of the rod body 1, and the second end cap 6 is located at the bottom of the rod body 1. The two end caps cover both ends of the rod body 1 respectively, and together they enclose to form a closed whole.

[0035] In this embodiment, the grouting pipe 3 is longitudinally inserted along the rod body 1. One end passes through the first end cap 5 and enters the rod body 1, continuing downward to above the second end cap 6 and bending to extend out of the rod body 1 from the side. The other end of the grouting pipe 3 extends above the first end cap 5, i.e., the outer side of the top of the rod body 1. This arrangement allows the grouting pipe 3 to penetrate the entire rod body 1. After the anchor is implanted and fixed, secondary grouting can be performed from the top outer opening to the bottom. The grout reaches the bottom of the hole directly through the grouting pipe 3, effectively filling the gaps or voids formed by the first grouting. The pre-embedded pipe 4 is also installed through the first end cap 5. One end is inserted into the rod body 1 and is filled and fixed with concrete, while the other end extends to the outer side of the first end cap 5 for installation and connection with external structures (such as reserved steel bars or connectors in the foundation slab). Through this pre-embedded pipe 4, a direct force transmission path is established between the anchor and the upper structure, eliminating the need for on-site rebar installation or welding, simplifying the construction process and improving connection reliability.

[0036] In some embodiments, such as Figure 1 and Figure 2 As shown, the embedded pipe 4 includes an embedded sleeve 41 and a connecting steel bar 42. The embedded sleeve 41 is fixed at the first end cap 5 and is entirely located inside the rod body 1; one end of the connecting steel bar 42 is assembled and connected to the embedded sleeve 41, and the other end extends to the outside of the rod body 1 as a joint for connection with the external structure.

[0037] Specifically, the embedded sleeve 41 is fixedly installed at the first end cap 5, entirely within the rod body 1 and encased in concrete. The inner wall of the embedded sleeve 41 has internal threads or grooves for assembly with the connecting steel bar 42. One end of the connecting steel bar 42 is detachably or permanently connected to the embedded sleeve 41 by means of thread engagement, snap locking, or welding, while the other end extends to the outside of the rod body 1 as a joint for connection with external structures.

[0038] Through the above structure, the embedded sleeve 41 is integrated with the first end cap 5 and the filling concrete of the rod body 1 during the factory prefabrication stage, ensuring positioning accuracy and anchoring reliability. Meanwhile, the connecting steel bar 42 can be flexibly configured with different lengths, diameters, or connection methods according to the actual needs of the construction site, without needing to determine the final connection dimensions at the factory stage, thus improving the versatility and on-site adaptability of the components. At the same time, the assembly connection method between the connecting steel bar 42 and the embedded sleeve 41 also facilitates future inspection or replacement, reducing maintenance costs.

[0039] In some embodiments, such as Figure 1 As shown, the frame 2 includes: multiple steel bars 21 and multiple stirrups 22; the multiple steel bars 21 extend along the length direction of the rod body 1, and are anchored at both ends to the first end cap 5 and the second end cap 6 respectively, and are in a prestressed tension state; the multiple stirrups 22 are sleeved on the outside of the multiple steel bars 21 and tied and fixed to each steel bar 21.

[0040] In this embodiment, multiple reinforcing bars 21 extend parallel to or spirally along the length of the rod 1, with their ends anchored to the first end cap 5 and the second end cap 6, respectively. Multiple stirrups 22 are sleeved on the outside of the multiple reinforcing bars 21, distributed at certain intervals along the length of the rod 1, and fixed to each reinforcing bar 21 by binding or welding. The function of the stirrups 22 is to constrain the multiple reinforcing bars 21 into a whole reinforcing cage skeleton 2, enhance the lateral stiffness of the skeleton 2, prevent the reinforcing bars 21 from buckling or shifting during transportation, hoisting, and installation, and at the same time bear part of the shear stress, further improving the structural stability of the skeleton 2.

[0041] Specifically, such as Figures 1 to 3 As shown, there are eight reinforcing bars 21, evenly distributed along the length of the rod 1, arranged in a circular or rectangular array. The eight reinforcing bars 21 are arranged in parallel, with their ends passing through the first end cap 5 and the second end cap 6, respectively. The reinforcing bars 21 are made of high-strength steel. Stirrups 22 are continuously arranged along the length of the rod 1 at certain intervals, and are fitted over the eight reinforcing bars 21. The stirrups 22 are made of hot-rolled ribbed steel bars, and the spacing is set according to design requirements. The stirrups 22 are fixed to each reinforcing bar 21 by binding or spot welding to form a complete reinforcing cage skeleton 2.

[0042] In some embodiments, such as Figure 1As shown, both the first end cap 5 and the second end cap 6 are anchor plates made of high-strength steel, possessing sufficient rigidity and load-bearing capacity to withstand the concentrated load generated by the tensioning of the reinforcing bars 21. Multiple reinforcing bars 21 are arranged parallel to each other along the length of the rod 1, with their ends passing through pre-set anchoring holes on the first end cap 5 and the second end cap 6, respectively, and directly locked to the outer surface of the end caps by anchorages. During tensioning, the designed prestress value is applied to the reinforcing bars 21 using specialized equipment. After reaching the set tension force, the anchorages are locked, firmly fixing both ends of the reinforcing bars 21 to the end caps, thus maintaining the reinforcing bars 21 in the pre-set tensioned state. This locking method creates a reliable force transmission path between the reinforcing bars 21 and the end caps, and the tension force of the reinforcing bars 21 is evenly transmitted to the concrete of the rod 1 through the end caps, giving the rod 1 effective prestress. During subsequent concrete filling and on-site construction, this prestress remains in a tensile state, effectively suppressing the generation and development of cracks in the rod 1 under load, and significantly improving the crack resistance, fatigue resistance, and durability of the anchor rod. Optionally, the axial cross-section of the rod 1 is square. Compared to traditional circular cross-section anchors, the square cross-section has a larger lateral surface area for the same diameter, thereby increasing the contact area between the anchor and the surrounding soil or rock, effectively improving the anchor's pull-out bearing capacity. Simultaneously, the square cross-section has a larger cross-sectional area for the same diameter, resulting in stronger compressive strength and allowing for the application of more prestress, thus providing greater tensile strength. Furthermore, the square cross-section facilitates standardized formwork fabrication and precise positioning of the frame 2 and embedded parts during factory prefabrication, reducing processing difficulty and cost. During transportation, the square cross-section allows for better stacking and transport. When the anchor is installed on-site, the square cross-section also possesses certain torsional resistance, better maintaining the directional stability of the rod 1 and facilitating alignment with external structures.

[0043] Based on the above embodiments, in some embodiments, such as Figure 1 As shown, after pouring concrete in the factory and curing it to the design strength, the portions of the skeleton 2, the grouting pipe 3, and the embedded pipe 4 located within the rod are tightly wrapped into a single unit. Through the encapsulation of concrete, the reinforcing bars 21 and stirrups 22 of the skeleton 2 are firmly embedded in the concrete, forming an integral load-bearing unit, effectively preventing relative displacement or loosening of the skeleton 2 during subsequent transportation, hoisting, and service. Simultaneously, the portions of the grouting pipe 3 and the embedded pipe 4 located within the rod are also completely encapsulated and fixed by concrete, ensuring that these two pipes maintain their designed positions throughout the entire lifespan of the anchor rod, avoiding displacement or damage to the pipes due to vibration or load.

[0044] In this embodiment, the concrete integrates the skeleton, grouting pipe, embedded pipe and the rod itself into one, making the entire anchor rod a cohesive whole structure. The load is evenly transferred between the rod, skeleton and each embedded part, which significantly improves the overall stiffness, bearing capacity and durability of the anchor rod.

[0045] This application also provides a construction method for anti-buoyancy anchor bolts, such as... Figure 4 As shown, it includes the following steps: Step 410: Drill holes at the construction site according to the geological conditions to form anchor bolt holes, and grout into the anchor bolt holes.

[0046] Step 420: Before the filler material initially sets, the pre-formed anti-buoyancy anchor rod is inserted into the bottom of the anchor rod hole, so that the filler material injected at one time can fully fill the gap between the anti-buoyancy anchor rod and the hole wall.

[0047] Step 430: After a predetermined time interval after the anti-buoyancy anchor bolts are installed, secondary grouting is performed to the bottom of the hole through the grouting pipe.

[0048] Step 440: Connect the external extension end of the pre-embedded pipe to the external structure.

[0049] In this embodiment, the anti-buoyancy anchor rod is manufactured using standardized prefabrication in a factory. First, a rod forming mold is prepared according to the design dimensions. The pre-welded steel reinforcement frame is placed into the mold; simultaneously, the grouting pipe and the embedded pipe are fixed in the designed positions. The grouting pipe runs longitudinally along the rod body, with both ends extending out of the bottom and top of the mold, respectively. One end of the embedded pipe is inserted into the area where the mold is located, and the other end extends out of the outside of the mold. Then, concrete is poured into the mold and vibrated to compact it, so that the concrete covers the frame, grouting pipe, and embedded pipe.

[0050] Afterward, the poured poles are cured until the concrete reaches its design strength. Once curing is complete, the formwork is removed, and the surface of the poles is inspected and repaired. After passing inspection, they are numbered and stored, awaiting transport to the construction site.

[0051] The construction method for this anti-buoyancy anchor includes the following steps: First, the location and depth of the anchor bolt holes are determined at the construction site based on the geological survey report. The anchor bolt holes are formed by drilling rigs, and grouting is carried out into the anchor bolt holes. The first grouting usually uses cement mortar or cement paste. The grouting pressure and mix ratio are determined according to the design requirements to ensure the stability of the hole wall and provide initial anchoring force.

[0052] Secondly, before the initial setting of the grout, the prefabricated anti-buoyancy anchor rod is inserted into the bottom of the anchor hole. During the insertion process, the rod should be kept vertical and centered so that the grout can fully fill the gap between the anti-buoyancy anchor rod and the hole wall, expel excess air, and form a uniform coating layer.

[0053] Then, after the anti-buoyancy anchor bolts are implanted and a predetermined time interval has elapsed, typically after the initial grouting has fully set or reached a certain strength, a second grouting is performed through the grouting pipe to the bottom of the hole. The second grouting can be done using high-pressure grouting, which forces the grout into the voids or weak interlayers created by the initial grouting, further compacting the anchoring section and improving its pull-out bearing capacity.

[0054] Finally, after the secondary grout reaches the design strength, the external extension end of the embedded pipe is installed and connected to the external structure (such as the reserved steel bars or connectors in the foundation slab). The connection method can be mechanical connection, welding or threaded connection to ensure a clear and reliable force transmission path.

[0055] The construction method for the anti-buoyancy anchor provided in this application involves prefabricating a concrete anchor body in a factory and supporting it with a frame to ensure structural stability and prevent deformation or collapse. Simultaneously, a grouting pipe is inserted into the anchor body, extending to the bottom and top outer sides respectively. This allows for secondary grouting to be performed at the bottom after the anchor is implanted and fixed, effectively filling gaps or voids between the anchor body and the surrounding soil, thus significantly enhancing the bond between the anchor and the surrounding soil. Furthermore, the pre-embedded pipe provides a direct connection interface between the anchor and the external structure, eliminating the need for on-site rebar installation or welding, simplifying the construction process and improving connection reliability. In summary, this anti-buoyancy anchor effectively solves the technical problems of low construction efficiency, uncontrollable quality, difficulty in remedying grouting defects, and complex connections with external structures associated with existing anchors.

[0056] In some embodiments, the cross-section of the rod in the axial direction is square. Correspondingly, the borehole diameter of the anchor bolt is set to 1.5 to 1.8 times the side length of the square rod. This borehole diameter range takes into account both construction feasibility and anchoring effect: if the borehole diameter is too small (less than 1.5 times the side length), the rod will be difficult to insert smoothly, and the gap between the rod and the borehole wall will be too small, hindering the flow and filling of grout; if the borehole diameter is too large (greater than 1.8 times the side length), excessive grouting material will be required, increasing construction costs, and excessive gaps may lead to rod positioning deviations, affecting anchoring quality. The depth of the anchor bolt hole is not less than the length of the anti-buoyancy anchor bolt to ensure that the anchor bolt can be completely inserted into the hole, and its bottom can reach the designed bearing layer, thereby fully utilizing the pull-out bearing capacity of the anchor bolt.

[0057] Regarding the grouting process, the filler materials used for primary and / or secondary grouting are cement grout, cement mortar, or fine aggregate concrete. Cement grout has good fluidity and is suitable for high-pressure grouting that requires penetration into small voids; cement mortar and fine aggregate concrete have higher strength and shrinkage resistance, making them suitable for primary filling of larger voids. To ensure the compactness and bearing capacity of the anchorage section, the actual filling volume should not be less than 1.2 times the theoretical calculation value. The theoretical calculation value is determined based on the diameter and depth of the anchor hole and the volume of the implanted anti-buoyancy anchor. The requirement that the actual filling volume should not be less than 1.2 times the theoretical value is to compensate for the volume shrinkage of the grout during the hardening process, the loss due to seepage into the surrounding soil, and the extra space caused by possible local over-excavation or irregular hole walls, ensuring that the anchorage section is completely filled without voids.

[0058] In some embodiments, during the secondary grouting and connection steps, the predetermined time for secondary high-pressure grouting is set to 24 to 48 hours after the anchor bolt insertion. This time period is chosen based on the setting and hardening characteristics of the primary grout: within 24 hours, the primary grout basically completes its final setting and begins to acquire early strength, capable of withstanding the pressure of secondary grouting without damage; after 48 hours, the grout strength is too high, the splitting effect of secondary grouting weakens, and it is difficult to effectively squeeze into the voids formed by primary grouting. Therefore, the 24 to 48-hour window ensures that the primary grout has sufficient strength to support the secondary grouting pressure, and also ensures that the secondary grout successfully splits and fills the weak areas. The termination condition for secondary high-pressure grouting is set at a preset time for grouting pressure stabilization or ground grout emergence.

[0059] The grouting pressure stabilization preset time refers to maintaining the pressure for a certain period of time (usually 3-5 minutes) after reaching the design grouting pressure (e.g., 2.0-3.0 MPa), and observing that the pressure gauge reading does not drop significantly, indicating that the anchoring section has been fully filled and compacted by the grout. Ground grout overflow refers to the observation of grout overflowing from the borehole or nearby ground surface during the grouting process, indicating that the gap between the anchor hole and the surrounding soil has been completely filled, and continuing grouting would be wasteful. Grouting can be stopped when either of the two termination conditions is met, to ensure grouting quality while avoiding over-grouting.

[0060] In summary, the anti-buoyancy anchor and its construction method provided in this application have the following beneficial effects: First, it solves the problems of low construction efficiency and cumbersome procedures in existing anti-buoyancy anchor bolt construction. Through standardized prefabrication in the factory, it enables mass production of components and rapid on-site installation, significantly shortening the construction cycle, reducing on-site operation difficulty, and effectively meeting the needs of modern construction projects for rapid construction.

[0061] Secondly, it addresses the issue of poor quality in existing anchor bolt projects. By adopting a factory-prefabrication production method, components such as the bolt body, frame, grouting pipe, and embedded pipe are all manufactured and assembled in a controlled environment. This avoids the impact of on-site construction conditions and human factors on quality, ensuring the reliable quality and performance stability of the anchor bolts.

[0062] Third, the pull-out bearing capacity is significantly improved. By adopting a square cross-section rod design, the pull-out bearing capacity is increased by 27.3% compared to traditional round anchor rods under the same diameter conditions. This improvement effectively reduces the number or length of anchor rods used, lowers project costs, and improves economic efficiency.

[0063] Fourth, it addresses the problems of poor durability and susceptibility to corrosion of existing anti-buoyancy anchors. Through factory prefabrication combined with prestressed tensioning technology, the anchor remains under compression throughout the entire process of bearing pull-out loads, ensuring the anchor body does not crack. This isolates groundwater from direct contact with the reinforcing steel, effectively preventing corrosion and significantly improving the anchor's durability, thus guaranteeing the structure's anti-buoyancy safety throughout its entire lifespan.

[0064] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. An anti-buoyancy anchor bolt, characterized in that, include: The rod (1) is formed into a square column by pouring concrete; The frame (2) is set and supported within the rod body; Grouting pipe (3) is inserted through the rod (1), with one end extending to the bottom outside of the rod (1) and the other end extending to the top outside of the rod (1) for grouting after the anti-buoyancy anchor is fixed; The pre-embedded pipe (4) has one end embedded in the concrete of the rod (1) and the other end extends to the outside of the rod (1) for connection with the external structure.

2. The anti-buoyancy anchor bolt according to claim 1, characterized in that, The anti-buoyancy anchor also includes: a first end cap (5) and a second end cap (6); The first end cap (5) is disposed at the top of the rod (1), and the second end cap (6) is disposed at the bottom of the rod (1) to seal the frame (2) at both ends of the rod (1) for tensioning and locking. One end of the grouting pipe (3) passes through the first end cap (5), passes through the rod (1) and extends to the bottom side of the rod (1), and the other end of the grouting pipe (3) extends to the outside of the top of the rod (1). One end of the pre-embedded tube (4) passes through the first end cap (5) and is inserted into the rod body (1). The other end of the pre-embedded tube (4) extends to the outside of the first end cap (5) for connection with an external structure.

3. The anti-buoyancy anchor bolt according to claim 2, characterized in that, The embedded pipe (4) includes: embedded sleeve (41) and connecting steel bar (42); The pre-embedded sleeve (41) is fixed at the first end cap (5) and is entirely located inside the rod body (1); one end of the connecting steel bar (42) is assembled and connected to the pre-embedded sleeve (41), and the other end extends to the outside of the rod body (1) as a joint for connection with the external structure.

4. The anti-buoyancy anchor bolt according to claim 2, characterized in that, The skeleton (2) includes: multiple steel bars (21) and multiple stirrups (22); Multiple steel bars (21) extend along the length of the rod (1), and are anchored at both ends to the first end cap (5) and the second end cap (6) respectively, and are in a prestressed tension state; multiple stirrups (22) are sleeved on the outside of the multiple steel bars (21) and tied and fixed to each steel bar (21).

5. The anti-buoyancy anchor bolt according to claim 4, characterized in that, The first end cap (5) and the second end cap (6) are anchor plates. The two ends of the multiple steel bars (21) are directly locked to the first end cap (5) and the second end cap (6) respectively, so as to maintain the steel bars (21) in a pre-set tension state.

6. The anti-buoyancy anchor bolt according to claim 1, characterized in that, The cross-section of the rod (1) in the axial direction is square.

7. The anti-buoyancy anchor bolt according to any one of claims 1-6, characterized in that, The rod body (1) is filled with solidified concrete; the concrete encapsulates the skeleton (2), the portion of the grouting pipe (3) located inside the rod body (1) and the portion of the pre-embedded pipe (4) located inside the rod body (1) into a whole.

8. A construction method based on the anti-buoyancy anchor bolt according to any one of claims 1 to 7, characterized in that, Includes the following steps: Anchor bolt holes are drilled at the construction site according to the geological conditions, and grout is injected into the anchor bolt holes once. Before initial setting, the pre-formed anti-buoyancy anchor is inserted into the bottom of the anchor hole, so that the filler material of the first grouting fully fills the gap between the anti-buoyancy anchor and the hole wall; After a predetermined time interval after the anti-buoyancy anchor is implanted, secondary grouting is performed to the bottom of the hole through the grouting pipe (3); The external extension end of the pre-embedded pipe (4) is installed and connected to the external structure.

9. The construction method of the anti-buoyancy anchor bolt according to claim 8, characterized in that, The cross-section of the rod (1) in the axial direction is square, the borehole diameter of the anchor bolt hole is 1.5 to 1.8 times the side length of the rod (1), and the depth of the anchor bolt hole is not less than the length of the anti-buoyancy anchor bolt. The filler material for the primary grouting and / or the secondary grouting is cement grout, cement mortar, or fine aggregate concrete; the actual amount of filler material injected is not less than 1.2 times the theoretical calculation value, which is determined based on the diameter and depth of the anchor hole and the volume of the implanted anti-buoyancy anchor.

10. The construction method of the anti-buoyancy anchor bolt according to claim 8, characterized in that, In the secondary grouting and connection step, the predetermined time for secondary high-pressure grouting is 24 to 48 hours after the anchor bolt implantation operation; the termination condition for secondary high-pressure grouting is the grouting pressure stabilizing for a preset time or grout emerging from the ground.

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