Progressive variable-resistance yielding anchor rod and mounting method

Abstract

According to the progressive variable-resistance yielding anchor rod and the installation method, an anchor rod body penetrates through a pressure relief sleeve, a resistance ring and a nut are sequentially screwed at the rear end of the anchor rod body, the resistance sleeve is arranged between the pressure relief sleeve and the resistance ring in a sleeving mode and clamped on a cut-off ring, and a rubber plate is connected to the lower portion of a force bearing plate at one end of the pressure relief sleeve. The rubber cushion plate provides initial stress buffering and micro-deformation, the resistance ring, the nut and the anchor rod body transmit internal stress of surrounding rock, after the stress is increased, the whole body is driven to move in the pressure relief sleeve, along with inward movement of the resistance ring, the inner diameter of the resistance sleeve is decreased, and resistance is gradually increased until the resistance ring moves to the stop ring below the pressure relief sleeve; and the yielding anchor rod does not deform any more. The device has the advantages of being simple in structure, low in cost, high in operation applicability, safe and reliable, and is suitable for weak large-deformation surrounding rock reinforcement engineering.

Description

Technical Field

[0001] This invention belongs to the field of geotechnical engineering surrounding rock support technology, specifically relating to a progressive variable resistance relief anchor bolt and its installation method. Background Technology

[0002] Rock bolts provide effective reinforcement and stabilization for soil and rock reinforcement projects, improving the bearing capacity of the soil and rock and significantly enhancing the safety of construction. However, with the expansion of application scenarios and the diversification and complexity of geological conditions, rigid rock bolts cannot effectively adapt to the large deformation requirements of weak surrounding rock, and are prone to brittle fracture stress failure, leading to safety accidents. To effectively adapt to the special requirements of large deformation surrounding rock, existing technologies have proposed a pressure-yielding technique to increase the deformation of the rock bolt to accommodate the deformation of the surrounding rock, avoid rock bolt failure, and continuously provide effective and stable anchoring stress. This can increase the ability of rock bolts to cope with complex and diverse large deformation surrounding rock masses, achieving the goal of effective and safe construction.

[0003] In existing pressure-relief anchor bolt technologies, some solutions employ central pressure relief, with the pressure-relief sleeve located in the middle of the anchor bolt. This approach suffers from drawbacks such as large drilling diameter and high cement grout filling volume. Other solutions involve pressure relief at the anchor bolt end, but most of these also require secondary drilling after the initial drilling to accommodate the pressure-relief sleeve. These solutions not only suffer from large drilling, installation difficulties, and high workload, but also maintain a near-constant resistance during pressure relief. Therefore, a novel structure is needed to address these challenges. Summary of the Invention

[0004] In order to overcome the shortcomings of the prior art, the purpose of this invention is to provide a progressive variable resistance relief anchor bolt and its installation method, which has the characteristics of simple structure, low cost and easy operation, and improves the safety of the surrounding rock and the versatility of the anchor bolt.

[0005] To achieve the above objectives, the technical solution of the present invention is as follows: A progressive variable resistance pressure relief anchor bolt includes an anchor bolt body (1), characterized in that: the anchor bolt body (1) passes through a pressure relief sleeve (4), the rear end of the anchor bolt body (1) is sequentially tightened with a resistance ring (7) and a nut (8), a resistance sleeve (6) is fitted between the pressure relief sleeve (4) and the resistance ring (7) and is locked on a stop ring (5), and a rubber plate (3) is connected under the load-bearing plate (2) at one end of the pressure relief sleeve (4).

[0006] The resistance sleeve (6) is a variable diameter ring with a thinner upper end and a thicker lower end. The outer diameter of the resistance sleeve (6) is smaller than the inner diameter of the pressure relief sleeve (4), and the inner diameter of the resistance sleeve (6) is smaller than the inner diameter of the stop ring (5). The slope and diameter of the resistance sleeve (6) are set according to the pressure relief stroke and resistance change requirements.

[0007] The resistance ring (7) is a circular ring, and the outer diameter of the resistance ring (7) is smaller than the inner diameter of the pressure relief sleeve (4). The nut (8) is an external hexagonal internal thread nut, and its outer diameter is smaller than that of the resistance ring (7). It is then screwed onto the anchor rod body (1) after the resistance ring (7).

[0008] The load-bearing plate (2), the stop ring (5) and the pressure relief sleeve (4) are made as a single integrated molding process.

[0009] The yield strength of the anchor rod body (1) is greater than that of the resistance sleeve (6) and the resistance ring (7), and the yield strength of the pressure relief sleeve (4) and the stop ring (5) is greater than that of the resistance sleeve (6) and the resistance ring (7). The resistance ring (7) can be deformed appropriately.

[0010] The rubber pad (3) is a square plate with a round hole in the middle. The diameter of the round hole is slightly larger than the outer diameter of the pressure relief sleeve (4). A steel plate is placed in the middle of the rubber plate. The rubber plate has compressibility and elasticity.

[0011] A method for installing a progressively variable resistance relief anchor bolt, characterized by the following steps: Step 1: The anchor drilling machine performs drilling and cleaning. Step 2: Fill the front cavity of the built-in anchor bolt with resin anchoring agent, and use the anchor bolting machine to push the entire built-in anchor bolt body to the bottom of the anchor hole; Step 3: Use the anchor bolt machine to rotate the rear anchor bolt body in the opposite direction, so that the bolt body rotates and pushes the resin anchoring agent forward, which enters the middle of the anchor bolt and the surrounding rock (9) through the grout outlet hole of the anchor head; Step 4: The anchor bolt machine rotates in the forward direction, driving the anchor bolt body and anchor head cutter to stir the anchoring agent. The anchoring agent components AB are stirred evenly and come into full contact with the surrounding rock (9). Step 5: After the anchoring agent has cured and the anchor rod body and the surrounding rock (9) are integrated, the rubber pad and the pressure relief sleeve are inserted from the rear end of the anchor rod body in sequence. The resistance sleeve (6) of the specifications determined according to the process design is inserted into the pressure relief sleeve. The resistance ring (7) and nut (8) are installed. The pre-tightening force is applied to the anchor rod by using a torque wrench and a pre-tightening sleeve. Step 6: After the pre-tightening force is reached, use a grouting machine to grout from the tail of the hollow rod. Grouting should be stopped after the grout has filled the entire anchor hole. Step 7: Once the grout has reached the required strength, conduct a pull-out test to verify the anchoring effect of the anchor bolt. Step 8: Periodically measure the deformation of the surrounding rock (9) and compare it with the pressure relief of the anchor rod body to comprehensively assess the safety of the surrounding rock (9).

[0012] The anchor bolting machine has a rotational stirring speed greater than 300 r / min and a stirring time of 20–40 s; The torque wrench pre-tightening nut pushes the resistance ring (7) into the pressure relief sleeve (4) and presses it against the resistance sleeve (6). As the resistance increases, the pre-tightening force increases. After reaching the design stress, the pre-tightening construction stops.

[0013] The rubber pad (3) provides initial stress buffering and micro-deformation. The resistance ring (7), nut (8) and anchor rod (1) transmit the internal stress of the surrounding rock (9). After the stress increases, it drives the whole to move in the pressure relief sleeve (4). As the resistance ring (7) moves inward, the inner diameter of the resistance sleeve (6) becomes smaller, and the resistance gradually increases until it moves to the stop ring (5) under the pressure relief sleeve (4), so that the anchor rod no longer deforms.

[0014] The beneficial effects of this invention are: (1) The progressive variable resistance relief anchor bolt of the present invention consists of an anchor bolt body, a rubber pad, a pressure relief sleeve, a resistance sleeve, a resistance ring, and a nut, forming a variable resistance relief pressure relief structure. It can provide pressure relief support for complex and variable large deformation rock and soil masses, which is beneficial to improving the stability of surrounding rock deformation control. The resistance ring, nut, and anchor bolt body transmit the internal stress of the surrounding rock. After the stress increases, it drives the whole to move in the pressure relief sleeve. As the resistance ring moves inward, the inner diameter of the resistance sleeve decreases, and the resistance gradually increases until it moves to the stop ring under the pressure relief sleeve. The amount of pressure relief can be adjusted by the length of the pressure relief sleeve. The prestress can be adjusted by changing the inner diameter of the resistance sleeve as needed to provide continuously increasing variable resistance, effectively improving the anchoring effect.

[0015] (2) The progressive variable resistance relief anchor bolt of the present invention has a simple structure and is easy to install. It does not require manual secondary hole enlargement. The installation of the relief anchor bolt can be completed by mechanical drilling only once, which greatly improves the construction efficiency and installation effect.

[0016] (3) The rubber pad provides a micro-deformation in the initial stage, which not only provides the amount of deformation but also makes the stress surface of the surrounding rock and structure larger and more uniform. At the same time, the micro-deformation and the pressure relief sleeve form a good cooperation, which improves the deformation effect of the component. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the invention.

[0018] Figure 2 This is a schematic diagram of the structure of the rod body of the present invention, showing the sliding under pressure.

[0019] Figure 3 This is a detailed schematic diagram of the resistance sleeve.

[0020] Among them, 1 is the anchor rod body, 2 is the bearing plate, 3 is the rubber plate, 4 is the pressure relief sleeve, 5 is the stop ring, 6 is the resistance sleeve, 7 is the resistance ring, 8 is the nut, and 9 is the surrounding rock (9). Detailed Implementation

[0021] The invention will be further described below with reference to the accompanying drawings.

[0022] like Figure 1 As shown, a progressive variable resistance pressure relief anchor bolt and its installation method include an anchor bolt body 1, a rubber pad 3, a pressure relief sleeve 4, a resistance sleeve 6, a resistance ring 7, and a nut 8. The anchor bolt body 1 passes through the pressure relief sleeve 4, and the rear end of the anchor bolt body 1 is sequentially tightened with the resistance ring 7 and the nut 8. The resistance sleeve 6 is fitted between the pressure relief sleeve 4 and the resistance ring 7 and is secured to the stop ring 5. A rubber plate 3 is connected to the underside of the load-bearing plate 2.

[0023] The resistance sleeve 6 is a variable diameter ring that is thinner at the top and thicker at the bottom. The outer diameter of the resistance sleeve 6 is smaller than the inner diameter of the pressure relief sleeve 4, and the inner diameter of the resistance sleeve 6 is smaller than the inner diameter of the stop ring 5. The slope and diameter variation of the resistance sleeve 6 are set according to the pressure relief stroke and resistance change requirements.

[0024] The resistance ring 7 is a circular ring, and the outer diameter of the resistance ring 7 is smaller than the inner diameter of the pressure relief sleeve 4. The nut 8 is an external hexagonal internal thread nut, and its outer diameter is smaller than that of the resistance ring 7. It is then screwed onto the anchor rod body 1 after the resistance ring 7.

[0025] The load-bearing plate 2, the stop ring 5, and the pressure relief sleeve 4 are manufactured as a single piece.

[0026] The yield strength of the anchor rod body 1 is greater than that of the resistance sleeve 6 and the resistance ring 7. The yield strength of the pressure relief sleeve 4 and the stop ring 5 is greater than that of the resistance sleeve 6 and the resistance ring 7. The resistance ring 7 can be deformed to a certain extent.

[0027] The rubber pad 3 is a square plate with a round hole in the middle. The diameter of the round hole is slightly larger than the outer diameter of the pressure relief sleeve 4. A steel plate is placed in the middle of the rubber plate. The rubber plate has compressibility and elasticity.

[0028] The aforementioned progressive variable resistance relief anchor bolt and installation method are characterized by the following steps: Step 1: The anchor drilling machine performs drilling and cleaning. Step 2: Fill the front cavity of the built-in anchor bolt with resin anchoring agent, and use the anchor bolting machine to push the entire built-in anchor bolt body to the bottom of the anchor hole; Step 3: Use the anchor bolt machine to rotate the rear anchor bolt body in the opposite direction, so that the bolt body rotates and pushes the resin anchoring agent forward, which enters the middle of the anchor bolt and the surrounding rock (9) through the grout outlet hole of the anchor head; Step 4: The anchor bolt machine rotates in the forward direction, driving the anchor bolt body and anchor head cutter to stir the anchoring agent. The anchoring agent components AB are stirred evenly and come into full contact with the surrounding rock (9). Step 5: After the anchoring agent has cured and the anchor rod body and the surrounding rock (9) are integrated, the rubber pad and the pressure relief sleeve are inserted from the rear end of the anchor rod body in sequence. The resistance sleeve 6, which is determined according to the process design, is inserted into the pressure relief sleeve. The resistance ring 7 and nut 8 are installed. The anchor rod is pre-tightened by the torque wrench and the pre-tightening sleeve. Step 6: After the pre-tightening force is reached, use a grouting machine to grout from the tail of the hollow rod. Grouting should be stopped after the grout has filled the entire anchor hole. Step 7: Once the grout has reached the required strength, conduct a pull-out test to verify the anchoring effect of the anchor bolt. Step 8: Periodically measure the deformation of the surrounding rock (9) and compare it with the pressure relief of the anchor rod body to comprehensively assess the safety of the surrounding rock (9).

[0029] The anchor bolting machine has a rotational stirring speed greater than 300 r / min and a stirring time of 20–40 s; The torque wrench pre-tightening nut pushes the resistance ring 7 into the pressure relief sleeve 4 and presses it against the resistance sleeve 6. As the resistance increases, the pre-tightening force increases. After reaching the design stress, the pre-tightening construction stops.

[0030] The rubber pad 3 provides initial stress buffering and micro-deformation. The resistance ring 7, nut 8 and anchor rod 1 transmit the internal stress of the surrounding rock (9). After the stress increases, it drives the whole to move in the pressure relief sleeve 4. As the resistance ring 7 moves inward, the inner diameter of the resistance sleeve 6 becomes smaller, and the resistance gradually increases until it moves to the stop ring 5 under the pressure relief sleeve 4, so that the anchor rod no longer deforms.

[0031] The working principle of this invention is: The progressive variable resistance relief anchor bolt consists of an anchor bolt body, a rubber pad, a pressure relief sleeve, a resistance sleeve, a resistance ring, and a nut, forming a variable resistance pressure relief structure. It can provide pressure relief support for complex and variable large deformation rock and soil masses, which is beneficial to improving the stability of deformation control of the surrounding rock (9). The resistance ring, nut, and anchor bolt body transmit the internal stress of the surrounding rock (9) through the cement grout at the end of the anchor bolt and other parts. After the stress increases, it drives the whole to move in the pressure relief sleeve. As the resistance ring moves inward, the inner diameter of the resistance sleeve decreases, and the resistance gradually increases until it moves to the stop ring under the pressure relief sleeve. The amount of pressure relief can be adjusted by the length of the pressure relief sleeve. The prestress can be adjusted as needed to change the inner diameter of the resistance sleeve to provide continuously increasing variable resistance, effectively improving the anchoring effect.

Claims

1. A progressively variable resistance relief anchor bolt, comprising an anchor bolt body (1), characterized in that: The anchor rod (1) passes through the pressure relief sleeve (4). The rear end of the anchor rod (1) is tightened with the resistance ring (7) and the nut (8) in sequence. The resistance sleeve (6) is placed between the pressure relief sleeve (4) and the resistance ring (7) and is locked on the stop ring (5). The bearing plate (2) at one end of the pressure relief sleeve (4) is connected to the rubber plate (3).

2. The progressively variable resistance relief anchor bolt according to claim 1, characterized in that, The resistance sleeve (6) is a variable diameter ring with a thinner upper end and a thicker lower end. The outer diameter of the resistance sleeve (6) is smaller than the inner diameter of the pressure relief sleeve (4), and the inner diameter of the resistance sleeve (6) is smaller than the inner diameter of the stop ring (5). The slope and diameter of the resistance sleeve (6) are set according to the pressure relief stroke and resistance change requirements.

3. The progressively variable resistance relief anchor bolt according to claim 1, characterized in that, The resistance ring (7) is a circular ring, and the outer diameter of the resistance ring (7) is smaller than the inner diameter of the pressure relief sleeve (4). The nut (8) is an external hexagonal internal thread nut, and its outer diameter is smaller than that of the resistance ring (7). It is then screwed onto the anchor rod body (1) after the resistance ring (7).

4. The progressively variable resistance relief anchor bolt according to claim 1, characterized in that, The load-bearing plate (2), the stop ring (5) and the pressure relief sleeve (4) are made as a single integrated molding.

5. A progressively variable resistance relief anchor bolt according to claim 1, characterized in that, The yield strength of the anchor rod body (1) is greater than that of the resistance sleeve (6) and the resistance ring (7), the yield strength of the pressure relief sleeve (4) and the stop ring (5) is greater than that of the resistance sleeve (6) and the resistance ring (7), and the resistance ring (7) can be deformed appropriately.

6. A progressively variable resistance relief anchor bolt according to claim 1, characterized in that, The rubber pad (3) is a square plate with a round hole in the middle. The diameter of the round hole is slightly larger than the outer diameter of the pressure relief sleeve (4). A steel plate is placed in the middle of the rubber plate. The rubber plate has compressibility and elasticity.

7. A progressively variable resistance relief anchor bolt according to claim 1, characterized in that, The installation method includes the following steps: Step 1: The anchor drilling machine performs drilling and cleaning. Step 2: Fill the front cavity of the built-in anchor bolt with resin anchoring agent, and use the anchor bolting machine to push the entire built-in anchor bolt body to the bottom of the anchor hole; Step 3: Use the anchor bolt machine to rotate the rear anchor bolt body in the opposite direction, so that the bolt body rotates and pushes the resin anchoring agent forward, which enters the middle of the anchor bolt and the surrounding rock (9) through the grout outlet hole of the anchor head; Step 4: The anchor bolt machine rotates in the forward direction, driving the anchor bolt body and anchor head cutter to stir the anchoring agent. The anchoring agent components AB are stirred evenly and come into full contact with the surrounding rock (9). Step 5: After the anchoring agent has cured and the anchor rod body and the surrounding rock (9) are integrated, the rubber pad and the pressure relief sleeve are inserted from the rear end of the anchor rod body in sequence. The resistance sleeve (6) of the specifications determined according to the process design is inserted into the pressure relief sleeve. The resistance ring (7) and nut (8) are installed. The pre-tightening force is applied to the anchor rod by using a torque wrench and a pre-tightening sleeve. Step 6: After the pre-tightening force is reached, use a grouting machine to grout from the tail of the hollow rod. Grouting should be stopped after the grout has filled the entire anchor hole. Step 7: Once the grout has reached the required strength, conduct a pull-out test to verify the anchoring effect of the anchor bolt. Step 8: Periodically measure the deformation of the surrounding rock (9) and compare it with the pressure relief of the anchor rod body to comprehensively assess the safety of the surrounding rock (9).

8. The installation method of a progressive variable resistance relief anchor bolt according to claim 7, characterized in that, The anchor bolting machine has a rotational stirring speed greater than 300 r / min and a stirring time of 20–40 s.

9. The installation method of a progressive variable resistance relief anchor bolt according to claim 7, characterized in that, The torque wrench pre-tightening nut pushes the resistance ring (7) into the pressure relief sleeve (4) and presses it against the resistance sleeve (6). As the resistance increases, the pre-tightening force increases. After reaching the design stress, the pre-tightening construction stops.

10. The installation method of a progressive variable resistance relief anchor bolt according to claim 7, characterized in that, The rubber pad (3) provides initial stress buffering and micro-deformation. The resistance ring (7), nut (8) and anchor rod (1) transmit the internal stress of the surrounding rock (9). After the stress increases, it drives the whole to move in the pressure relief sleeve (4). As the resistance ring (7) moves inward, the inner diameter of the resistance sleeve (6) becomes smaller, and the resistance gradually increases until it moves to the stop ring (5) under the pressure relief sleeve (4), so that the anchor rod no longer deforms.

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