Bag type expansion anchor rod and construction method thereof
By using a bladder-type expanded anchor structure and dual grouting technology, the problem of interface failure of traditional expanded anchors under complex geological conditions has been solved, improving the anchor's load-bearing capacity and the controllability of construction quality.
Patent Information
- Application Number
- CN202511456323.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-10-13
- Publication Date
- 2025-11-25
AI Technical Summary
Traditional expanded-body anchors are prone to interface failure between the grout and the soil under complex geological conditions, resulting in insufficient anchor bearing capacity. Furthermore, the concealed nature of the construction process makes quality control difficult.
The structure adopts a bladder-type expanded anchor bolt, which includes the anchor bolt body, the expanded umbrella-shaped skeleton and the bladder body. High polymer grout is injected through inner and outer grouting pipes to form a double reinforcement layer, optimize the force transmission mechanism, and enhance the interface strength and anchoring effect.
It improves the load-bearing capacity and service life of anchor bolts, enhances the bond between anchor bolts and soil, solves the interface failure problem of traditional anchor bolts under complex geological conditions, and ensures controllable construction quality.
Smart Images
Figure CN121006789A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of rock and soil anchoring support technology, specifically to a bladder-type expanded anchor rod and its construction method. Background Technology
[0002] With the development of geotechnical engineering, the bearing capacity and economic requirements of geotechnical reinforcement technologies in the construction of foundation pits, slope protection, and foundations are becoming increasingly stringent, and the geological conditions encountered are becoming increasingly complex. Traditional anti-buoyancy and anti-pull-out anchors, as commonly used geotechnical reinforcement structures, have always played an important role. However, their structural forms and reinforcement performance are no longer sufficient to meet the needs of practical engineering in situations with complex and special geotechnical properties. Expanded-body anchors, as a new type of geotechnical reinforcement member, have better stress and deformation characteristics, and their widespread application in slope reinforcement, foundation engineering, and foundation pit engineering has significant engineering value. The failure modes of expanded-body anchors can be divided into five types based on the failure location when the anchor reaches its pull-out limit: ① failure along the contact surface between the grout and the anchor body; ② failure along the contact surface between the grout and the geotechnical mass; ③ anchor body breakage; ④ shear failure of the grout; ⑤ shear failure of the anchored stratum. Currently, commonly used expanded-body anchor technologies on the market include plain grout anchors and encased-body expanded-body anchor technologies. For anchor bolts, the bolt body is relatively controllable, and different bolt bodies with varying pull-out strengths can be configured according to different pull-out force requirements. Anchoring shear failure typically depends on the anchor bolt's dimensional parameters and geological conditions. In practical engineering, it is not the primary failure mode compared to other types of failure modes, and due to the objective nature of geological conditions, improving the anchor bolt's load-bearing capacity by avoiding this failure mode is not very meaningful. In actual engineering, the main failure modes are interface failure between the grout and the soil / rock, between the grout and the bolt body, and shear failure of the grout. When the anchor bolt itself resists pull-out, it does so through the interaction between the bolt body and the grout. During this process, the grout is prone to developing load-bearing cracks, which gradually accumulate during the anchor bolt's operation, eventually leading to the failure of the bond strength between the bolt body and the grout, and the anchor bolt fails along the contact surface between the grout and the bolt body. The construction process of the grout is a concealed project, and many factors affect its quality and are uncontrollable. Therefore, its strength sometimes fails to meet design requirements, resulting in shear failure during the anchor bolt's load-bearing process. Grouting in clay, weak, pebble, gravel, or weathered rock layers often results in interface failure because the strength of these strata is often lower than that of concrete, and the interface strength between the anchor body and the surrounding soil is insufficient. Therefore, it is necessary to consider polymer grouting at the two interfaces of the working anchor and to improve the force transmission mechanism between the anchor body and the grout. This will increase the shear strength of the surrounding soil and rock and maintain the bond strength between the grout and the anchor body, allowing the grout to exert its good compressive strength, ultimately improving the anchor's load-bearing capacity and service life. Summary of the Invention
[0003] To address the problems mentioned in the background section, this invention provides a bladder-type expanded anchor bolt and its construction method. The technical solution adopted by this invention is as follows:
[0004] The above-mentioned objective of this application is achieved through the following technical solution:
[0005] A bladder-type expanded anchor bolt includes an anchor bolt body. An expanded end umbrella-shaped frame is fixedly installed at the bottom of the anchor bolt body. An upper expanded umbrella-shaped frame is also fixedly installed above the expanded end umbrella-shaped frame. A bladder body is provided around the outer periphery of the expanded end umbrella-shaped frame and the upper expanded umbrella-shaped frame. The top of the inner wall of the bladder body abuts against the upper expanded umbrella-shaped frame, and the bottom of the inner wall of the bladder body abuts against the expanded end umbrella-shaped frame. A plurality of bladder inner grouting pipes are abutted against the outer periphery of the anchor bolt body, extending from the outside of the bladder body to the inside of the bladder body. A plurality of bladder outer grouting pipes are abutted against the outer periphery of the bladder body.
[0006] In a preferred embodiment, this application may be further configured such that: both the outer grouting pipe and the inner grouting pipe of the bladder are provided with one-way valve grouting ports at the points where they abut against the bladder body.
[0007] In a preferred embodiment, this application can be further configured as follows: injecting an external polymer grout into the periphery of the bag body through the one-way valve grouting port of the external grouting pipe of the bag, wherein the external polymer grout is one of a penetrating or expanding polymer grouting material; and injecting an internal grout into the interior of the bag body through the one-way valve grouting port of the internal grouting pipe of the bag.
[0008] In a preferred embodiment, this application may be further configured such that: a protective cap is fixedly installed at the bottom of the anchor rod body based on a nut, and the protective cap is used to limit the bottom of the grouting bag body after grouting.
[0009] In a preferred embodiment, this application may be further configured such that a circular fixing plate is fixedly installed on the anchor rod above the bag body.
[0010] The second objective of this invention is achieved through the following technical solution:
[0011] A construction method for a bladder-type expanded anchor bolt includes the following steps:
[0012] S10: Anchor Bolt Assembly and Lowering: Assemble the anchor bolts on the ground according to the design. Fix the grouting bag body in the designated position. Secure the grouting pipes on the outside and inside of the grouting bag to the grouting bag body to ensure unobstructed grouting channels. Slowly lower the assembled anchor bolts into the preset hole, avoiding collisions with the hole wall during lowering to prevent damage to the grouting bag. After reaching the designed depth, fix the anchor bolts at the preset hole opening using a circular fixing plate.
[0013] S20: Intra-bag grouting: First, prepare cement grout and other grouts according to the design mix ratio. The initial grouting is injected into the inside of the bag body through the grouting pipe inside the bag, controlling the grouting pressure within the range of 0.5 to 1.0 MPa. Stop when the grout overflows from the grouting pipe inside the bag. After the initial grouting is completed and a certain time is waited, high-pressure grout of 2 to 5 MPa is injected into the inside of the bag body again through the grouting pipe inside the bag to expand the bag body.
[0014] S30: External grouting: After the grout inside the bladder has solidified, a permeable or expanding polymer grouting material is selected as the external polymer grouting material based on the geological conditions of the construction location; secondary grouting is performed by injecting 1 to 2 MPa of grout into the gap between the bladder body and the borehole wall through the grouting pipe on the outside of the bladder to fill the gap between the bladder body and the borehole wall.
[0015] S40: Tensioning and Locking: After the grout inside the bladder and the polymer grout outside the bladder reach the design strength, a secure tensioning device is installed on the top of the anchor rod. The device is started to slowly and evenly apply tension according to the design tension stress and procedure, and the tension value and the elongation of the anchor rod are recorded. After tensioning to the design stress value, it is held for 5-10 minutes, and then the anchor rod is locked with an anchor to put it in a tensile state to achieve anchoring.
[0016] S50: Sealing: After tensioning and locking, clean the hole opening of debris and grout residue, and seal the preset hole opening with cement mortar according to the designed sealing length to prevent rainwater and debris from entering and ensure the durability of the anchor rod.
[0017] In a preferred embodiment, this application may be further configured to include the step of: prior to step S10, the following step is also included:
[0018] S01: Construction Preparation: Before construction, the site must be leveled, the quality of construction materials must be strictly inspected, and the status and parameters of the equipment must be adjusted to ensure that its performance is normal and that all parameters meet the construction requirements. According to the design, the pre-set hole positions must be accurately positioned and marked. When drilling the pre-set hole positions, the specified hole diameter, hole depth, and inclination must be followed, the drilling speed must be controlled, and rock cuttings and soil must be cleaned up in a timely manner. After the hole is formed, the hole depth, hole diameter, and inclination must be checked with a borehole measuring instrument to ensure that the hole formation quality meets the standards.
[0019] The beneficial effects of the bladder-type expanded anchor bolt and its construction method of the present invention are as follows:
[0020] 1. By installing an external grouting pipe on the outside of the grouting bag body, after grouting inside the grouting bag body is completed, a polymer grouting material is injected into the interface between the grouting material inside the grouting bag and the surrounding soil through the external grouting pipe (for soil layers with low permeability coefficients, such as clay, a permeable polymer is injected; for soil layers with high permeability coefficients, such as sand, an expansive polymer is injected), thereby increasing the interface strength, compressing the surrounding soil, improving the interface's resistance to damage, and having the advantage of being adaptable to different soil layers by selecting different types of polymers.
[0021] 2. By setting an umbrella-shaped skeleton force transmission rod system at the upper and lower ends of the bag body, the force transmission mechanism of the expanded body anchor rod is optimized, thereby improving the safety and reliability of the expanded body anchor rod. Attached Figure Description
[0022] Figure 1 This is a schematic front view of the enclosed anchor bolt in an embodiment of the present invention, which is a bladder-type expanded anchor bolt and its construction method.
[0023] Figure 2 This is a cross-sectional structural schematic diagram of the bladder-type expanded anchor bolt in an embodiment of the present invention;
[0024] Figure 3 For the present invention Figure 2 A schematic diagram of the cross-sectional structure with section line AA in the diagram;
[0025] Figure 4 For the present invention Figure 2 A cross-sectional view of the structure with BB as the section line.
[0026] The components include: 1. Anchor rod body; 2. Grouting pipe outside the bladder bag; 3. Grouting pipe inside the bladder bag; 4. Circular fixing plate; 5. Umbrella-shaped skeleton at the top of the expansion body; 6. One-way valve grouting port; 7. Bladder bag body; 8. Umbrella-shaped skeleton at the end of the expansion body; 9. Nut; 10. Grouting body inside the bladder bag; 11. Polymer grouting body outside the bladder bag; 12. Protective cap. Detailed Implementation
[0027] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0028] As attached Figure 1-4As shown, a bladder-type expanded anchor bolt includes an anchor bolt body 1. An expanded end umbrella-shaped frame 8 is fixedly installed at the bottom of the anchor bolt body 1. An upper expanded umbrella-shaped frame 5 is also fixedly installed above the expanded end umbrella-shaped frame 8. A bladder body 7 is provided around the outer periphery of the expanded end umbrella-shaped frame 8 and the upper expanded umbrella-shaped frame 5. The top of the inner wall of the bladder body 7 abuts against the upper expanded umbrella-shaped frame 5, and the bottom of the inner wall of the bladder body 7 abuts against the expanded end umbrella-shaped frame 8. A plurality of bladder inner grouting pipes 3 are provided abutting against the outer periphery of the anchor bolt body 1. The bladder inner grouting pipes 3 extend from the outside of the bladder to the inside of the bladder body 7 along the outer periphery of the anchor bolt body 1. A plurality of bladder outer grouting pipes 2 are provided abutting against the outer periphery of the bladder body 7.
[0029] In this embodiment, a double-layer support structure is formed by the umbrella-shaped skeleton 8 at the bottom of the anchor rod 1 and the upper umbrella-shaped skeleton 5 above it. This, along with the outer bag body 7 and the grouting pipes extending from the outer periphery of the anchor rod 1 to the inside and outside of the bag, enhances the contact area between the bag and the soil by utilizing the unfolding characteristics of the umbrella-shaped skeleton. Grout is injected through the inner and outer grouting pipes to form a composite anchor body, thus solving the problems of insufficient expansion stability and poor bonding between the grout and the soil caused by the single support structure in traditional bag-type expanded anchor rods.
[0030] In one embodiment, the outer grouting pipe 2 and the inner grouting pipe 3 of the bag are both provided with one-way valve grouting ports 6 at the points where they abut against the bag body 7.
[0031] In this embodiment, by setting a one-way valve grouting port 6 at the connection between the outer grouting pipe 2 and the inner grouting pipe and the bag body 7, the grout can flow into the inner and outer spaces of the bag in only one direction during grouting and cannot flow back. This solves the problems of grout backflow, uneven filling inside and outside the bag or local voids caused by pressure fluctuations during the grouting process, and ensures the compactness of the grout body.
[0032] In one embodiment, an outer polymer grout 11 is injected into the outer periphery of the bag body 7 via the one-way valve grouting port 6 of the outer grouting pipe 2, wherein the outer polymer grout 11 is one of a penetrating or expanding polymer grouting material; and an inner grout 10 is injected into the inside of the bag body 7 via the one-way valve grouting port 6 of the inner grouting pipe 3.
[0033] In this embodiment, by injecting a permeable or expansive polymer grout (such as polyurethane) into the outside of the bladder and simultaneously injecting high-grade cement grout into the inside of the bladder, the permeability of the polymer material fills the pores of the soil or the expansive material squeezes the surrounding soil, forming a double reinforcement layer inside and out. This solves the problem that traditional grout is easily contaminated by soil impurities and that the anchoring force is weakened due to insufficient strength of the aggregate.
[0034] In one embodiment, a protective cap 12 is fixedly installed at the bottom of the anchor rod 1 based on a nut 9. The protective cap 12 is used to limit the bottom of the grout bag body 7 after grouting.
[0035] In this embodiment, by setting a protective cap 12 with a nut 9 at the bottom of the anchor rod body 1, a mechanical limit is formed on the bottom of the grouting bag after grouting, preventing it from deforming or displacing due to grouting pressure or external load. This solves the problem of overall anchor rod tilt and reduced bearing capacity caused by insufficient support at the bottom of the bag.
[0036] In one embodiment, a circular fixing plate 4 is also fixedly installed on the anchor rod 1 above the bag body 7.
[0037] In this embodiment, by setting a circular fixing plate 4 above the bag body 7, the top of the bag is rigidly constrained, which prevents the top of the bag from moving upward or local wrinkling during the grouting expansion process, thus solving the problem of reduced anchoring efficiency caused by insufficient height or irregular shape of the expanded section.
[0038] Furthermore, a construction method for a bladder-type expanded anchor bolt includes the following steps:
[0039] S10: Anchor Bolt Assembly and Lowering: Assemble the anchor bolts on the ground according to the design. Fix the grouting bag body in the designated position. Secure the grouting pipes on the outside and inside of the grouting bag to the grouting bag body to ensure unobstructed grouting channels. Slowly lower the assembled anchor bolts into the preset hole, avoiding collisions with the hole wall during lowering to prevent damage to the grouting bag. After reaching the designed depth, fix the anchor bolts at the preset hole opening using a circular fixing plate.
[0040] S20: Intra-bag grouting: First, prepare cement grout and other grouts according to the design mix ratio. The initial grouting is injected into the inside of the bag body through the grouting pipe inside the bag, controlling the grouting pressure within the range of 0.5 to 1.0 MPa. Stop when the grout overflows from the grouting pipe inside the bag. After the initial grouting is completed and a certain time is waited, high-pressure grout of 2 to 5 MPa is injected into the inside of the bag body again through the grouting pipe inside the bag to expand the bag body.
[0041] S30: External grouting: After the grout inside the bladder has solidified, a permeable or expanding polymer grouting material is selected as the external polymer grouting material based on the geological conditions of the construction location; secondary grouting is performed by injecting 1 to 2 MPa of grout into the gap between the bladder body and the borehole wall through the grouting pipe on the outside of the bladder to fill the gap between the bladder body and the borehole wall.
[0042] S40: Tensioning and Locking: After the grout inside the bladder and the polymer grout outside the bladder reach the design strength, a secure tensioning device is installed on the top of the anchor rod. The device is started to slowly and evenly apply tension according to the design tension stress and procedure, and the tension value and the elongation of the anchor rod are recorded. After tensioning to the design stress value, it is held for 5-10 minutes, and then the anchor rod is locked with an anchor to put it in a tensile state to achieve anchoring.
[0043] S50: Sealing: After tensioning and locking, clean the hole opening of debris and grout residue, and seal the preset hole opening with cement mortar according to the designed sealing length to prevent rainwater and debris from entering and ensure the durability of the anchor rod.
[0044] In a preferred embodiment, this application may be further configured to include the step of: prior to step S10, the following step is also included:
[0045] S01: Construction Preparation: Before construction, the site must be leveled, the quality of construction materials must be strictly inspected, and the status and parameters of the equipment must be adjusted to ensure that its performance is normal and that all parameters meet the construction requirements. According to the design, the pre-set hole positions must be accurately positioned and marked. When drilling the pre-set hole positions, the specified hole diameter, hole depth, and inclination must be followed, the drilling speed must be controlled, and rock cuttings and soil must be cleaned up in a timely manner. After the hole is formed, the hole depth, hole diameter, and inclination must be checked with a borehole measuring instrument to ensure that the hole formation quality meets the standards.
[0046] The present invention and its embodiments have been described above. This description is not restrictive. The accompanying drawings are only one embodiment of the present invention. The actual structure is not limited to this. In short, if a person skilled in the art is inspired by this description and designs a similar structure and embodiment without departing from the spirit of the present invention, such design should fall within the protection scope of the present invention.
Claims
1. A type of expanded-body anchor bolt, characterized in that: The system includes an anchor rod body (1), with an expanded end umbrella-shaped frame (8) fixedly installed at the bottom of the anchor rod body (1). An upper expanded umbrella-shaped frame (5) is also fixedly installed on the anchor rod body (1) above the expanded end umbrella-shaped frame (8). A bag body (7) is wrapped around the outer periphery of the expanded end umbrella-shaped frame (8) and the upper expanded umbrella-shaped frame (5). The top of the inner wall of the bag body (7) abuts against the upper expanded umbrella-shaped frame (5), and the bottom of the inner wall of the bag body (7) abuts against the expanded end umbrella-shaped frame (8). Several bag inner grouting pipes (3) are provided on the outer periphery of the anchor rod body (1). The bag inner grouting pipes (3) extend from the outside of the bag to the inside of the bag body (7) along the outer periphery of the anchor rod body (1). Several bag outer grouting pipes (2) are provided on the outer periphery of the bag body (7).
2. The enlarged-body anchor bolt according to claim 1, characterized in that: One-way valve grouting ports (6) are provided at the contact portions of the outer grouting pipe (2) and the inner grouting pipe (3) of the bag with the bag body (7).
3. A bladder-type expanded anchor bolt according to claim 2, characterized in that: Based on the one-way valve grouting port (6) of the outer grouting pipe (2) of the bag, an outer polymer grouting body (11) is injected into the outer periphery of the bag body (7), and the outer polymer grouting body (11) is one of the penetrating or expanding polymer grouting materials; based on the one-way valve grouting port (6) of the inner grouting pipe (3) of the bag, an inner grouting body (10) is injected into the inside of the bag body (7).
4. A bladder-type expanded anchor bolt according to claim 1, characterized in that: The bottom of the anchor rod (1) is fixedly installed with a protective cap (12) based on a nut (9). The protective cap (12) is used to limit the bottom of the grout bag body (7) after grouting.
5. A bladder-type expanded anchor bolt according to claim 1, characterized in that: A circular fixing plate (4) is also fixedly installed on the anchor rod (1) above the bag body (7).
6. A construction method for a bladder-type expanded anchor bolt, characterized in that: Including the following steps: S10: Anchor Bolt Assembly and Lowering: Assemble the anchor bolts on the ground according to the design. Fix the grouting bag body in the designated position. Secure the grouting pipes on the outside and inside of the grouting bag to the grouting bag body to ensure unobstructed grouting channels. Slowly lower the assembled anchor bolts into the preset hole, avoiding collisions with the hole wall during lowering to prevent damage to the grouting bag. After reaching the designed depth, fix the anchor bolts at the preset hole opening using a circular fixing plate. S20: Intra-bag grouting: First, prepare cement grout and other grouts according to the design mix ratio. The initial grouting is injected into the inside of the bag body through the grouting pipe inside the bag, controlling the grouting pressure within the range of 0.5 to 1.0 MPa. Stop when the grout overflows from the grouting pipe inside the bag. After the initial grouting is completed and a certain time is waited, high-pressure grout of 2 to 5 MPa is injected into the inside of the bag body again through the grouting pipe inside the bag to expand the bag body. S30: External grouting: After the grout inside the bladder has solidified, a permeable or expanding polymer grouting material is selected as the external polymer grouting material based on the geological conditions of the construction location; secondary grouting is performed by injecting 1 to 2 MPa of grout into the gap between the bladder body and the borehole wall through the grouting pipe on the outside of the bladder to fill the gap between the bladder body and the borehole wall. S40: Tensioning and Locking: After the grout inside the bladder and the polymer grout outside the bladder reach the design strength, a secure tensioning device is installed on the top of the anchor rod. The device is started to slowly and evenly apply tension according to the design tension stress and procedure, and the tension value and the elongation of the anchor rod are recorded. After tensioning to the design stress value, it is held for 5-10 minutes, and then the anchor rod is locked with an anchor to put it in a tensile state to achieve anchoring. S50: Sealing: After tensioning and locking, clean the hole opening of debris and grout residue, and seal the preset hole opening with cement mortar according to the designed sealing length to prevent rainwater and debris from entering and ensure the durability of the anchor rod.
7. The construction method of a bladder-type expanded anchor bolt according to claim 6, characterized in that: Before step S10, the following step is also included: S01: Construction Preparation: Before construction, the site must be leveled, the quality of construction materials must be strictly inspected, and the status and parameters of the equipment must be adjusted to ensure that its performance is normal and that all parameters meet the construction requirements. According to the design, the pre-set hole positions must be accurately positioned and marked. When drilling the pre-set hole positions, the specified hole diameter, hole depth, and inclination must be followed, the drilling speed must be controlled, and rock cuttings and soil must be cleaned up in a timely manner. After the hole is formed, the hole depth, hole diameter, and inclination must be checked with a borehole measuring instrument to ensure that the hole formation quality meets the standards.