Pressure stabilizing type expansion anchor rod
By designing a pressure-stabilized expanded anchor bolt, the problems of insufficient contact area and inaccurate positioning of traditional anchor bolts in complex strata are solved. This enables multi-segment differentiated expansion and precise grouting, improving anchoring force and construction efficiency, and enhancing the stability and applicability of the anchor bolt.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- DAYUAN CONSTR GRP
- Filing Date
- 2025-06-03
- Publication Date
- 2026-05-15
AI Technical Summary
Traditional anchor structures have limited contact area in complex strata, making it difficult to form differentiated interlocking effects. Furthermore, the lack of effective positioning and grouting control leads to uneven distribution of anchoring force, which can easily result in local slippage or overall failure.
The pressure-stabilized expanded anchor bolt adopts a central bearing rod and a variable cross-section expanded mechanism, combined with positioning components and a grouting system, to achieve multi-segment differentiated expansion and precise grouting, thereby increasing the contact area and interlocking force between the anchor bolt and the rock and soil. The compressive strength is improved through elastic bladders and fiber reinforcement layers, ensuring uniform distribution of grout.
It significantly improves the pull-out bearing capacity and applicability of anchor bolts, enhances anchoring stability, reduces construction complexity and operational risks, and improves positioning accuracy and construction efficiency.
Smart Images
Figure CN224243854U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of building technology. More specifically, this utility model relates to a pressure-stabilizing expanded anchor bolt. Background Technology
[0002] In geotechnical engineering, the anchoring performance of anchor bolts directly affects the stability of engineering structures. Traditional anchor bolt structures typically use a single-diameter expanded section, which has a limited contact area with the surrounding soil and rock, making it difficult to meet the pull-out bearing capacity requirements of complex strata or high-load conditions. Especially in strata of alternating soft and hard textures or loose soil, uniform expanded sections are difficult to form differentiated interlocking, easily leading to local slippage or overall failure. Furthermore, the lack of effective centering and positioning measures during anchor bolt installation makes them susceptible to borehole deviation or irregular borehole walls, resulting in anchor bolt eccentricity. This eccentricity causes uneven distribution of anchoring force, reduces the overall effectiveness of the anchor bolt, and may even lead to stress concentration risks.
[0003] The main reasons for the above problems are twofold: First, the expansion section of traditional anchor bolts has a single shape, making it impossible to actively adapt to the differences in mechanical properties of different strata through structural design. Second, the anchor bolt positioning components are insufficient in function, making it difficult to achieve stable alignment under complex drilling conditions. For example, some anchor bolts use rigid support plates for positioning, which have limited elastic adjustment capabilities and are prone to jamming or displacement when the borehole wall is uneven. In addition, controlling the uniformity of grout flow during grouting is difficult; improper distribution of grouting pressure in different sections may lead to insufficient grout filling in some areas or excessive expansion and rupture of the bladder. These factors collectively restrict the reliability of the anchor bolt anchoring effect and its engineering applicability.
[0004] Solving these problems has presented several technical challenges: how to achieve multi-segment differentiated expansion of the anchor bolt within a limited space while ensuring effective engagement between each expanded segment and the formation; how to design a positioning mechanism that can accommodate drilling deviations while maintaining the anchor bolt in a centered position; and how to precisely control grouting parameters to avoid uneven grout distribution. These requirements place high demands on material properties, structural design, and construction techniques, which traditional technical solutions struggle to address simultaneously. Summary of the Invention
[0005] One object of this invention is to solve at least the problems described above and to provide at least the advantages that will be explained later.
[0006] To achieve these objectives and other advantages according to this utility model, a pressure-stabilized expanded anchor bolt is provided, comprising: an anchor bolt body and a variable cross-section expanded mechanism; the anchor bolt body includes a central bearing rod and a positioning assembly disposed on the outer periphery of the central bearing rod; the variable cross-section expanded mechanism includes at least two expandable sections distributed along the axial direction of the central bearing rod, each expandable section comprising an expansion sleeve, an elastic bladder wrapped around the outside of the expansion sleeve, and a grouting assembly independently connected to the elastic bladder, wherein the elastic bladder forms expanded sections of different diameters after grout is injected through the grouting assembly, so that the variable cross-section expanded mechanism as a whole has a stepped or frustum-shaped variable cross-section structure.
[0007] Preferably, the central support rod has at least two independent grouting channels inside;
[0008] Adjacent expandable sections are connected by transition rings, the top of the uppermost elastic bladder is connected to a top pressure plate, and the bottom of the lowermost elastic bladder is connected to a bottom pressure plate.
[0009] The top bearing plate and the transition ring are both provided with grouting channels in the radial direction. The grouting channel in the top bearing plate is connected to the uppermost elastic bladder, and the grouting channel in the transition ring is connected to the elastic bladder below it. Each grouting channel is connected to at least two independent grouting channels in the central bearing rod.
[0010] The grouting assembly includes at least two grouting pipes, each of which is connected to at least two independent grouting channels within the central support rod.
[0011] Preferably, both the top pressure plate and the transition ring are provided with vent holes. The vent hole in the top pressure plate is connected to the uppermost elastic bladder, and the vent hole in the transition ring is connected to the elastic bladder below it. The vent hole is provided with a one-way valve that opens from the side of the elastic bladder to the outside.
[0012] Preferably, each grouting pipe is connected to the independent grouting channel via a detachable quick-connect fitting, and the quick-connect fitting is equipped with a backflow prevention check valve.
[0013] Preferably, the inlet end of the grouting pipe converges into a main grouting interface, which has a built-in pressure sensor and a flow distribution valve. The pressure sensor is signal-connected to the flow distribution valve and is used to dynamically adjust the grouting flow rate of each elastic bladder according to the real-time grouting pressure of each elastic bladder.
[0014] Preferably, the positioning component includes multiple sets of positioning winglets spaced apart along the axial direction of the central support rod, each set of positioning winglets including at least three elastic positioning pieces evenly distributed along the circumference of the central support rod, and the outer end of the elastic positioning piece is provided with an arc-shaped guide surface.
[0015] Preferably, the elastic capsule is composed of an outer fiber reinforcement layer and an inner elastic rubber layer, and the outer fiber reinforcement layer is provided with stress-reinforcing ribs along both the circumferential and axial directions.
[0016] Preferably, a nut is fitted at the lower end of the central support rod, and a conical sleeve is fitted over the nut. The conical sleeve has multiple guide holes evenly distributed around its conical surface.
[0017] This utility model has at least the following beneficial effects:
[0018] The anchor bolt's central load-bearing rod, combined with a positioning component design, utilizes the elastic support of an elastic positioning plate and the guidance of a circular arc guide surface to maintain the anchor bolt's centered position within the borehole, effectively reducing uneven anchoring force distribution caused by eccentricity. The variable cross-section expansion mechanism, through expandable sections of varying diameters forming stepped or frustum-shaped structures, significantly increases the contact area and interlocking force between the anchor bolt and the surrounding soil and rock, thereby enhancing its pull-out bearing capacity. This structure can adapt to the differentiated anchoring requirements of various geological formations, enhancing the anchor bolt's applicability and anchoring stability.
[0019] The independent grouting channel within the central support rod, connected to the grouting flow channels in the transition ring and bearing plate, enables precise, staged grouting, ensuring uniform grout filling in each expansion section. The combined use of a flow distribution valve and pressure sensor dynamically adjusts the flow distribution based on real-time grouting pressure, preventing localized overpressure that could lead to bladder rupture or insufficient grouting. The transition ring and bearing plate further enhance the overall structural stability, ensuring efficient grout delivery to all target areas.
[0020] The combination of an vent and a one-way valve effectively removes air from the elastic bladder, reducing air resistance and ensuring grout density and full bladder expansion. Quick-connect fittings simplify the connection process between the grouting pipe and the independent grouting channel, improving construction efficiency, while the anti-backflow check valve prevents grout from flowing back when grouting is interrupted, avoiding pipe blockage. This design balances ease of construction with system reliability, reducing operational complexity.
[0021] The composite structure of the elastic bladder significantly improves compressive strength and durability through the synergistic effect of the fiber reinforcement layer and stress-reinforcing ribs, reducing the risk of breakage during grouting. The design of the tapered sleeve and the guide hole optimizes the flow path of the grout at the bottom of the anchor bolt, enhancing the adhesion between the bottom and the stratum, and further improving the overall anchoring force. The standardized connection method between the nut and the tapered sleeve simplifies the installation process while ensuring structural stability.
[0022] Other advantages, objectives and features of this invention will be partly apparent from the following description, and partly understood by those skilled in the art through study and practice of this invention. Attached Figure Description
[0023] Figure 1 This is a schematic diagram of the external structure of the pressure-stabilized expanded body anchor bolt of this utility model;
[0024] Figure 2 This is a schematic diagram of the internal structure of the pressure-stabilized expanded body anchor rod of this utility model. Detailed Implementation
[0025] The present invention will now be described in further detail with reference to the accompanying drawings, so that those skilled in the art can implement it based on the description.
[0026] It should be noted that in the description of this utility model, the terms "horizontal", "longitudinal", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.
[0027] like Figure 1-2 As shown, this utility model provides a pressure-stabilized expanded anchor bolt, comprising: an anchor bolt body and a variable cross-section expanded mechanism; the anchor bolt body includes a central bearing rod 1 and a positioning component disposed on the outer periphery of the central bearing rod 1; the variable cross-section expanded mechanism includes at least two expandable sections distributed along the axial direction of the central bearing rod 1, each expandable section including an expansion sleeve 3, an elastic bladder 4 wrapped around the outside of the expansion sleeve 3, and a grouting component independently connected to the elastic bladder 4, wherein the elastic bladder 4 forms expanded sections with different diameters after grout is injected through the grouting component, so that the variable cross-section expanded mechanism as a whole has a stepped or frustum-shaped variable cross-section structure.
[0028] Specifically, the anchor body includes a central load-bearing rod 1 and a positioning assembly disposed on its outer periphery. The positioning assembly may be provided with 2-4 sets of positioning winglets at intervals along the axial direction of the central load-bearing rod 1. Each set of positioning winglets includes 3-5 elastic positioning pieces 2 evenly distributed along the circumference of the central load-bearing rod 1. The outer end of the elastic positioning piece 2 may be provided with an arc-shaped guide surface.
[0029] The elastic positioning plate 2 can be made of readily available components such as spring steel sheets or nylon elastic sheets, and the central support rod 1 can be made of readily available rods such as high-strength threaded steel bars or alloy steel pipes. The material of the elastic positioning plate 2 of the positioning assembly can be Q235 spring steel or nylon 66, and the material of the central support rod 1 can be HRB400 steel bars or No. 45 seamless steel pipes.
[0030] The positioning components are assembled on the outer periphery of the central support rod 1. Each group of positioning wing pieces is distributed along the axial direction of the central support rod 1 at the designed spacing. The elastic positioning pieces 2 in each group are uniformly fixed along the circumference of the central support rod 1.
[0031] When installing the anchor rod, the central support rod 1 drives the positioning component to be inserted into the borehole. The elastic positioning plate 2 is squeezed by the borehole wall and undergoes elastic deformation. The arc guide surface guides the anchor rod to be smoothly lowered into the borehole. At the same time, the tension of the elastic positioning plate 2 is used to keep the central support rod 1 in the center position of the borehole.
[0032] The number of expandable sections can be 2-3. The diameter of the expansion sleeve 3 can be 50mm, 70mm, or 90mm, and the diameter difference between adjacent expansion sections can be 30mm, 40mm, etc. The expansion sleeve 3 can be made of metal or plastic corrugated pipe. The grouting assembly can be made of PVC or steel grouting pipe, and the elastic bladder 4 is a commercially available expandable grouting bladder.
[0033] The elastic bladder 4 can be made of an inner layer of natural rubber or nitrile rubber and an outer layer of glass fiber reinforcement. The expansion sleeve 3 can be made of Q235 steel corrugated pipe or HDPE corrugated pipe. The expandable sections are arranged at the designed spacing along the axial direction of the central support rod 1. The expansion sleeve 3 is fitted outside the central support rod 1, and the elastic bladder 4 is tightly wrapped around the outside of the expansion sleeve 3.
[0034] During construction, an integrated drilling-jet-grouting anchor bolt construction method is adopted to form an opening in the non-anchored section and a jet-grouting expansion hole in the anchored section, so that the anchor hole is filled with cement grout. After the anchor bolt is guided into the designed position in the borehole, cement grout or cement mortar is injected into the elastic bladder 4 through the grouting component according to the design pressure and grouting volume. The grout pressure causes the elastic bladder 4 to expand and expand. Since the expansion sleeve 3 of each expandable section has a different diameter or different grouting pressure, expansion sections with different diameters are formed. Multiple expansion sections are combined along the axial direction to form a stepped or frustum-shaped structure.
[0035] In the above embodiments, the positioning component, through the elastic support of the elastic positioning piece 2 and the guiding effect of the arc-shaped guide surface, keeps the anchor rod body in a centered state in the borehole, improving the positioning accuracy of the anchor rod installation and avoiding the problem of uneven anchoring force caused by eccentricity. The variable cross-section expansion mechanism forms a stepped or frustum-shaped structure through expansion sections of different diameters, increasing the contact area and interlocking force between the anchor rod and the surrounding rock and soil, effectively improving the pull-out bearing capacity of the anchor rod, and adapting to the differentiated requirements of different geological conditions for the anchoring structure, thus enhancing the applicability and anchoring stability of the anchor rod.
[0036] Furthermore, the central support rod 1 is provided with at least two independent grouting channels 5 inside;
[0037] A transition ring 6 connects adjacent expandable sections, a top pressure plate 7 connects to the top of the uppermost elastic bladder 4, and a bottom pressure plate 8 connects to the bottom of the lowermost elastic bladder 4.
[0038] The top bearing plate 7 and the transition ring 6 are both provided with grouting channels 9 in the radial direction. The grouting channel 9 in the top bearing plate 7 is connected to the uppermost elastic bladder 4. The grouting channel 9 in the transition ring 6 is connected to the elastic bladder 4 below it. Each grouting channel 9 is connected to at least two independent grouting channels 5 in the central bearing rod 1.
[0039] The grouting assembly includes at least two grouting pipes, which are respectively connected to at least two independent grouting channels 5 inside the central support rod 1.
[0040] Furthermore, the inlet end of the grouting pipe converges into a main grouting interface, which has a built-in pressure sensor and a flow distribution valve. The pressure sensor is signal-connected to the flow distribution valve and is used to dynamically adjust the grouting flow rate according to the real-time grouting pressure of each elastic bladder 4.
[0041] Specifically, the central support rod 1 can be equipped with 2-3 independent grouting channels 5, with an inner diameter of 8mm, 10mm, or 12mm. The thickness of the transition ring 6 between adjacent expandable sections can be 20mm, 25mm, or 30mm, and the thickness of the top bearing plate 7 and bottom bearing plate 8 can be 15mm, 20mm, or 25mm. The diameter of the grouting channels 9 in the transition ring 6 and the top bearing plate 7 can be designed to be 6mm, 8mm, or 10mm. The top bearing plate 7, transition ring 6, and bottom bearing plate 8 can be connected to the central support rod 1 by thread or welding, while ensuring that the grouting channels 9 are connected to the independent grouting channels 5. The grouting pipe can be a PVC pipe or a seamless steel pipe, connected to the independent grouting channels 5 via quick-connect couplings.
[0042] The main grouting interface can integrate 2-3 grouting pipe inlets, and the range of the built-in pressure sensor can be set to 0-10MPa, 0-15MPa, or 0-20MPa. The flow distribution valve can be a proportional regulating valve or a solenoid valve, setting the grouting flow distribution ratio to 1:1, 1:2, or 1:3 based on real-time data from the pressure sensor. For example, when the grouting pressure of the upper elastic bladder 4 reaches 5MPa, the flow distribution valve automatically reduces the flow rate in that channel, prioritizing grouting into the lower channel with lower pressure.
[0043] In the above embodiments, the independent grouting channel 5 and the flow distribution valve enable precise grouting in stages, avoiding local overpressure that could cause the bladder to rupture. The transition ring 6 and the pressure plate enhance structural stability and ensure that the grout is evenly distributed to each expansion section.
[0044] Furthermore, both the top pressure plate 7 and the transition ring 6 are provided with vent holes 10. The vent hole 10 in the top pressure plate 7 is connected to the uppermost elastic bladder 4, and the vent hole 10 in the transition ring 6 is connected to the elastic bladder 4 below it. The vent hole 10 is provided with a one-way valve that opens from the side of the elastic bladder 4 to the outside.
[0045] Specifically, the diameter of the vent hole 10 can be set to 3mm, 4mm, or 5mm, and the opening pressure of the one-way valve can be set to 0.1MPa, 0.15MPa, or 0.2MPa. The one-way valve can be a spring-loaded or rubber diaphragm type, and is fixed to the vent hole 10 by threads during installation. During construction, when the gas pressure inside the elastic bladder 4 exceeds the set threshold, the one-way valve automatically opens to release gas, and the valve closes after the slurry injection is completed to prevent backflow.
[0046] In the above embodiments, the vent 10 and the one-way valve effectively remove air from the bladder, ensuring the compactness of the grout.
[0047] Furthermore, each grouting pipe is connected to the independent grouting channel 5 via a detachable quick-connect fitting, and the quick-connect fitting is equipped with a backflow prevention check valve.
[0048] Specifically, quick-connect couplings can be threaded or snap-fit type, with the inner diameter matching the outer diameter of the grouting pipe, such as 12mm, 15mm, or 18mm. The closing pressure of the anti-backflow check valve can be set to 0.05MPa, 0.1MPa, or 0.15MPa. During installation, the grouting pipe is quickly connected to the independent grouting channel 5 via the quick-connect coupling, and the check valve prevents grout backflow when grouting is interrupted.
[0049] In the above embodiments, quick-connect couplings simplify the construction process, and check valves prevent grout backflow from causing blockages.
[0050] Furthermore, the elastic capsule 4 is composed of an outer fiber reinforcement layer and an inner elastic rubber layer, and the outer fiber reinforcement layer is provided with stress-reinforcing ribs along both the circumferential and axial directions.
[0051] Specifically, the outer fiber reinforcement layer can be 1mm, 1.5mm, or 2mm thick, with the fibers woven in a cross pattern along the circumferential and axial directions at a density of 10, 15, or 20 fibers / cm. The inner elastic rubber layer can be 3mm, 5mm, or 8mm thick, with a Shore A hardness of 60A, 70A, or 80A. The stress-reinforcing ribs can be designed as protrusions 2mm wide and 1mm high, distributed along the surface of the capsule at intervals of 10mm, 15mm, or 20mm.
[0052] In the above embodiments, the fiber reinforcement layer and stress reinforcement ribs improve the compressive strength of the bladder and prevent rupture during grouting.
[0053] Furthermore, a nut 11 is fitted onto the lower end of the central support rod 1, and a conical sleeve 12 is fitted over the nut 11. The conical surface of the conical sleeve 12 is evenly provided with a plurality of guide holes 13 along the circumference.
[0054] Specifically, the cone angle of the cone sleeve 12 can be set to 30°, 45°, or 60°, and the diameter of the guide hole 13 is 5mm, 8mm, or 10mm, with 6, 8, or 10 holes evenly spaced along the circumference of the cone surface. The nut 11 can be a standard M20, M24, or M30 part, and is fixed to the lower end of the central support rod 1 by threads. After installation, the cone sleeve 12 covers the nut 11, and the guide hole 13 guides the grout to the bottom of the anchor rod, enhancing the bottom anchoring effect.
[0055] In the above embodiments, the cone sleeve 12 and the guide hole 13 optimize the slurry distribution and improve the adhesion between the bottom of the anchor bolt and the stratum.
[0056] Although the embodiments of this utility model have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for this utility model. For those skilled in the art, other modifications can be easily made. Therefore, without departing from the general concept defined by the claims and their equivalents, this utility model is not limited to the specific details and the illustrations shown and described herein.
Claims
1. A pressure-stabilizing expanded-body anchor bolt, characterized in that, include: An anchor bolt body and a variable cross-section expanding mechanism; the anchor bolt body includes a central support rod and a positioning assembly disposed on the outer periphery of the central support rod; the variable cross-section expanding mechanism includes at least two expandable sections distributed along the axial direction of the central support rod, each expandable section including an expansion sleeve, an elastic bladder wrapped around the outside of the expansion sleeve, and a grouting assembly independently connected to the elastic bladder, the elastic bladder forming expanding sections with different diameters after grout is injected through the grouting assembly, so that the variable cross-section expanding mechanism as a whole has a stepped or frustum-shaped variable cross-section structure.
2. The pressure-stabilizing expanded-body anchor bolt as described in claim 1, characterized in that, The central load-bearing rod is provided with at least two independent grouting channels inside; Adjacent expandable sections are connected by transition rings, the top of the uppermost elastic bladder is connected to a top pressure plate, and the bottom of the lowermost elastic bladder is connected to a bottom pressure plate. The top bearing plate and the transition ring are both provided with grouting channels in the radial direction. The grouting channel in the top bearing plate is connected to the uppermost elastic bladder, and the grouting channel in the transition ring is connected to the elastic bladder below it. Each grouting channel is connected to at least two independent grouting channels in the central bearing rod. The grouting assembly includes at least two grouting pipes, each of which is connected to at least two independent grouting channels within the central support rod.
3. The pressure-stabilizing expanded-body anchor bolt as described in claim 2, characterized in that, Both the top pressure plate and the transition ring are provided with vent holes. The vent hole in the top pressure plate is connected to the uppermost elastic bladder, and the vent hole in the transition ring is connected to the elastic bladder below it. The vent hole is provided with a one-way valve that opens from the side of the elastic bladder to the outside.
4. The pressure-stabilizing expanded-body anchor bolt as described in claim 2, characterized in that, Each grouting pipe is connected to the independent grouting channel via a detachable quick-connect fitting, and the quick-connect fitting is equipped with a backflow prevention check valve.
5. The pressure-stabilizing expanded-body anchor bolt as described in claim 2, characterized in that, The inlet end of the grouting pipe converges into a main grouting interface. The main grouting interface has a built-in pressure sensor and a flow distribution valve. The pressure sensor is signal-connected to the flow distribution valve and is used to dynamically adjust the grouting flow rate of each elastic bladder according to the real-time grouting pressure of each elastic bladder.
6. The pressure-stabilizing expanded-body anchor bolt as described in claim 1, characterized in that, The positioning component includes multiple sets of positioning winglets spaced apart along the axial direction of the central support rod. Each set of positioning winglets includes at least three elastic positioning pieces evenly distributed along the circumference of the central support rod. The outer end of each elastic positioning piece is provided with an arc-shaped guide surface.
7. The pressure-stabilizing expanded-body anchor bolt as described in claim 1, characterized in that, The elastic capsule is composed of an outer fiber reinforcement layer and an inner elastic rubber layer, and the outer fiber reinforcement layer is provided with stress-reinforcing ribs along both the circumferential and axial directions.
8. The pressure-stabilizing expanded-body anchor bolt as described in claim 1, characterized in that, The lower end of the central support rod is fitted with a nut, and the nut is covered with a conical sleeve. The conical surface of the conical sleeve is evenly provided with multiple guide holes along the circumference.