A constant resistance absorption and yield pressure monitoring anchor device and its use method

Abstract

The present invention discloses a constant resistance absorption and yield monitoring anchor rod device and a method of use thereof, which belongs to the field of underground engineering support such as lanes, tunnels, water diversion tunnels and chambers. It comprises a threaded rod body, an ordinary round steel rod body, a linear displacement sensor, a high-strength spring pull rod and a constant resistance device. With the help of the linear displacement sensor data and the elastic coefficient of the spring in the pull rod, the data can be processed to realize the monitoring of the preload force and the deformation of the surrounding rock; and the relative sliding between the constant resistance sleeve and the constant resistance slider in the constant resistance device can achieve the yield effect; and when the support resistance suddenly changes, the multiple high-strength spring pull rods can play a buffering and energy-absorbing role. The device can monitor the preload force and the deformation of the surrounding rock, and can also achieve the yield effect to resist the deformation and damage of the rock mass. It can also reduce the damage to the anchor rod when the support resistance suddenly changes. It has the advantages of diverse functions, reasonable structure and accurate data.

Description

Technical Field

[0001] The invention belongs to the field of underground engineering support of lanes, tunnels, diversion tunnels and chambers, and is applicable to a constant resistance absorption and yield stress monitoring anchor rod device and a use method thereof. Background Art

[0002] Anchor support technology for deep, high-stress soft rock has become a key tool for addressing the challenges of complex geological environments in underground projects. Deep underground, soft rock is subject to internal stratum stresses, often exhibiting a high tendency to deform and fail. Therefore, effective support measures are necessary to ensure the safe progress of the project. Anchor support can significantly improve the bearing capacity and stability of the surrounding rock in the tunnel. It is suitable for various soft rock formations (mudstone, shale, sandstone, etc.) and layered slate, offering strong applicability and flexibility. By selecting anchors of appropriate specifications and materials, the support requirements of different soft rock formations can be met.

[0003] However, deep soft rock is prone to large deformations that are difficult to predict and have strong destructive power. Once they occur, they will cause great harm. This requires that the anchor rod can not only provide a constant support force, but also produce a large elongation deformation to meet the requirements of large deformation of the surrounding rock. At the same time, it has the function of monitoring the deformation of the surrounding rock and the stress condition of the anchor rod, and can improve the stress condition of the anchor rod to avoid sudden impact and loss of the anchor rod. However, ordinary anchor rods are too stiff and have poor compression deformation performance. It is difficult to accurately monitor the stress condition of the anchor rod with existing methods, and there is also a lack of protection measures for the anchor rod. Based on the above problems, it is urgent to develop a device that can monitor the preload force and the deformation of the surrounding rock, and can also achieve a compression effect to resist the deformation and damage of the rock mass. It can also have a buffering and protective effect when the anchor rod stress suddenly changes, reducing damage to the anchor rod; that is, an anchor rod device that integrates monitoring, deformation compression, buffering and energy absorption, and active support functions to solve existing engineering and technical problems. Summary of the Invention

[0004] Technical problem: The purpose of the present invention is to overcome the shortcomings of the existing technology and provide a constant resistance absorption and pressure-yielding monitoring anchor device and its use method, which can not only monitor the preload force and surrounding rock deformation, but also achieve a pressure-yielding effect to resist the deformation and damage of the rock mass. It can also achieve buffering when the support resistance suddenly changes, thereby reducing damage to the anchor.

[0005] Technical Solution: To achieve the above technical objectives, the present invention proposes a constant resistance absorption and pressure-yielding monitoring anchor rod device, comprising an anchor rod body, the anchor rod body comprising a threaded rod body and a round steel rod body, the threaded rod body being connected to the round steel rod body via a constant resistance device, the threaded rod body being threadedly connected to an anti-slip nut and a piston-type tray; the constant resistance device is a resistance pulling mechanism with a pressure-yielding effect, and when the pulling force exceeds the internal design resistance, the constant resistance slider drives the threaded rod body to slide, thereby achieving energy absorption and stretching;

[0006] The constant resistance device includes a constant resistance sleeve of a piston-cylinder structure. The left side of the constant resistance sleeve is the cylinder bottom of the piston cylinder structure, and is fixedly connected to the tail end of the round steel rod body through a thread. The piston cavity in the constant resistance sleeve is a rough rectangular channel, and the four walls of the rough rectangular channel are rough surfaces with a concave-convex structure. A matching constant resistance slider serving as a piston is provided in the rough rectangular channel in the constant resistance sleeve, so that the constant resistance slider needs to overcome the designed friction resistance to move in the rough rectangular channel. The end of the threaded rod body passes through the opening on the right side of the constant resistance sleeve and extends into the rough rectangular channel to connect with the constant resistance slider to form a piston rod. A spring is provided between the constant resistance slider and the cylinder bottom of the piston cylinder structure of the constant resistance sleeve. The two ends of the spring are respectively connected to the cylinder bottom of the piston cylinder structure and the constant resistance slider through magnets. When the surrounding rock deforms and the constant resistance slider overcomes the resistance generated by the mutual compression with the rough surface of the concave-convex structure and slides, the spring fixed between the cylinder bottom of the piston cylinder structure and the constant resistance slider in a normally unstressed state is stretched accordingly. The tension generated by the spring stretching can limit the sliding of the slider, which is used to prevent the surrounding rock from continuing to deform.

[0007] Furthermore, a disc-mounted limiter is threadedly provided at the place where the round steel rod is connected to the constant resistance sleeve. A buffer device is provided between the limiter and the piston-type tray in parallel around the constant resistance device. The buffer device is a plurality of high-strength spring pull rods. The high-strength spring pull rod includes a hollow steel pipe. The bottom of the hollow steel pipe is fixed to the piston-type tray by bolts through the base. The upper end of the hollow steel pipe is fixed to the limiter by bolts through a movable rod. A high-strength spring in a tensile state is provided in the hollow steel pipe. The two ends of the high-strength spring are respectively connected to the bottom of the hollow steel pipe and the movable rod; under normal conditions, the high-strength spring in a tensile state enhances the support resistance; when the surrounding rock deformation causes the high-strength spring pull rod to continue to stretch, the spring elastic force continues to increase, and the resistance provided by the piston-type tray connected to the spring pull rod close to the rock surface will also increase.

[0008] Furthermore, a linear displacement sensor for measuring the sliding distance of the constant resistance slider relative to the constant resistance sleeve in the constant resistance device is provided between the limit body and the piston-type tray. The linear displacement sensor is connected to a multi-function instrument through a wire. With the help of the linear displacement sensor data and the characteristics of the high-strength spring in the high-strength spring pull rod, the multi-function instrument processes the data to realize the monitoring of the anchor rod preload and the surrounding rock deformation.

[0009] Furthermore, the material strength of the constant resistance sleeve is lower than that of the constant resistance slider, so it deforms before the constant resistance slider. The cross-section of the constant resistance sleeve material will be reduced due to tensile deformation. The sliding of the constant resistance slider requires greater pulling force, and the support effect is enhanced to prevent the constant resistance slider from being damaged by friction due to its low strength during the sliding process in the constant resistance sleeve, resulting in a resistance reduction effect; when the surrounding rock deforms, the piston-type tray is impacted, causing the constant resistance slider to frictionally slide along the rough surface of the concave and convex structure of the inner wall of the constant resistance sleeve, causing the entire rod body to stretch and deform, thereby resisting the deformation and damage of the rock mass and achieving a pressure-relieving effect; at the same time, the spring in the normal unstressed state inside the constant resistance device can coordinate the sliding deformation of the device. When the surrounding rock deforms, it is pulled and absorbs the deformation energy of the surrounding rock. The generated tension can limit the movement of the slider to prevent the constant resistance device from being damaged.

[0010] Furthermore, under the coordinated buffering action of the high-strength spring pull rod, the piston tray and the limit body, when the support resistance changes due to deformation of the surrounding rock and pre-tightening of the anti-slip wire nut, the tension provided by the high-strength spring pull rod can resist the harm caused by the instantaneous change of the support resistance, thereby preventing the anchor rod from being damaged due to bearing excessive load or absorbing too much energy, and at the same time protecting the constant resistance device.

[0011] Furthermore, an annular grouting plug for sealing the anchoring agent is provided on the round steel rod body.

[0012] A method for using a constant resistance absorption and pressure-dissipation monitoring anchor device, the steps of which are as follows:

[0013] Drill anchor holes at pre-marked locations in the surrounding rock, and install fixed steel limiters and annular grout stoppers on the anchor rods.

[0014] Put the anchoring agent (clay roll, curing agent roll) and anchor rod into the anchor hole, start the stirrer and stir until fully stirred;

[0015] After the anchoring agent solidifies, install the anti-slip nut outside the hole. By pre-tightening the anti-slip nut, the piston tray contacts the rock surface and sticks to it. At this time, the high-strength spring pull rod will be compressed, and relative displacement will occur between the constant resistance slider and the constant resistance casing. The linear displacement sensor between the piston tray and the limiter records the data, transmits it to the multi-function instrument, and displays the preload data after calculation based on the spring characteristics.

[0016] When pre-tightening force is provided along the threaded anchor rod by pre-tightening the anti-slip nut, the piston tray is squeezed and the support resistance provided by the pre-tightening force changes suddenly. The buffer device composed of the high-strength spring pull rod, the piston tray and the limiter can share part of the pre-tightening force that should be transmitted to the threaded rod body, thereby improving the stress condition of the anchor rod body. At this time, the constant resistance device and the four high-strength spring pull rods are regarded as a whole, and they work in coordination to resist the damage caused by the instantaneous change of the support resistance, thereby protecting the constant resistance device with poor integrity.

[0017] Furthermore, when the surrounding rock undergoes large deformation, the piston-type tray is impacted, causing the constant resistance slider to slide along the concave and convex surface of the inner wall of the constant resistance casing, causing the rod to stretch and deform. Through the structural change of the constant resistance device, the deformation and damage of the rock mass are resisted, achieving a pressure-relieving effect.

[0018] The linear displacement sensor can transmit the slip change data to the multi-function instrument. The slip change is the deformation of the surrounding rock. When the surrounding rock deforms, the piston tray is impacted, causing a sudden change in the support resistance. The tension generated by the high-strength spring pull rod in the buffer device resists the instantaneous change in the support resistance and causes harm. As the surrounding rock deforms, the high-strength spring continues to stretch, generating greater tension to resist the deformation of the surrounding rock and cause damage, thereby preventing the anchor rod from being damaged due to excessive load or absorbing too much energy.

[0019] Beneficial effects: The present invention has the function of monitoring the preload and deformation of the surrounding rock, achieving a pressure-releasing effect to resist the deformation and destruction of the rock mass, and also achieving buffering when the support resistance suddenly changes, thereby reducing damage to the anchor rod. This makes up for the fact that the existing pressure-releasing anchor rod cannot monitor the preload and deformation of the surrounding rock and provide buffering when the support resistance suddenly changes. By using the data of the linear displacement sensor and the high-strength spring characteristics of the high-strength spring pull rod, the multi-function instrument processes the data to achieve real-time monitoring of the anchor rod preload and the deformation of the surrounding rock; when the surrounding rock undergoes large deformation, the constant resistance slider in the constant resistance device frictionally slides along the rough surface of the concave-convex structure of the inner wall of the constant resistance casing, and maintains the constant resistance characteristics during the sliding process. Through the structural changes of the constant resistance device, the deformation and destruction of the rock mass are resisted to achieve a pressure-releasing effect; through the action of the high-strength spring pull rod, when the support resistance suddenly changes, the instantaneous change of the support resistance is resisted to cause harm, thereby preventing the anchor rod from being damaged due to bearing too much load or absorbing too much energy. This multifunctional anchor device addresses the inability of conventional anchors to withstand large deformations of the surrounding rock. It also addresses the inability of existing yielding anchors to monitor preload and surrounding rock deformation, as well as provide a buffering function when support resistance suddenly changes. Furthermore, it boasts diverse functions, a rational structure, and accurate data, effectively reducing accidents and ensuring worker safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 Schematic diagram of the anchor hole in the embodiment of the present invention;

[0021] Figure 2 Schematic diagram of a constant resistance absorption and yield stress monitoring anchor device according to an embodiment of the present invention;

[0022] Figure 3 This is a schematic diagram of the installation of a constant resistance absorption and yield stress monitoring anchor device according to an embodiment of the present invention;

[0023] Figure 4 Schematic diagram of a constant resistance device in a constant resistance absorption and yield stress monitoring anchor device according to an embodiment of the present invention;

[0024] Figure 5 Schematic diagram of a constant resistance slider in a constant resistance absorption and yield stress monitoring anchor device according to an embodiment of the present invention;

[0025] Figure 6 Schematic diagram of a high-strength spring pull rod in the anchor device constant resistance absorption and yield stress monitoring anchor device of the present invention;

[0026] Figure 7 It is a front and cross-sectional schematic diagram of the limiting body in the constant resistance absorption and yield stress monitoring anchor device of the anchor device of the present invention.

[0027] In the figure: 1-surrounding rock, 2-anchor hole, 3-anti-slip nut, 4-piston tray, 5-constant resistance device, 6-threaded rod, 7-ordinary round steel rod, 8-high-strength spring pull rod, 9-annular slurry stopper, 10-anchor agent, 11-linear displacement sensor, 12-limiting body, 13-bolt, 14-conducting wire, 15-instrument, 16-constant resistance slider, 17-constant resistance sleeve, 18-magnet, 19-spring, 20-high-strength spring, 21-movable rod, 22-hollow steel pipe, 23-base, 24-screw hole. DETAILED DESCRIPTION

[0028] The present invention will be further described below with reference to the embodiments in the accompanying drawings:

[0029] like Figure 3 、 Figure 4 and Figure 6As shown, a constant resistance absorption and pressure-releasing monitoring anchor rod device of the present invention includes an anchor rod body, and the anchor rod body includes a threaded rod body 6 and a round steel rod body 7. The threaded rod body 6 is connected to the round steel rod body 7 through a constant resistance device 5, and the threaded rod body 6 is threadedly connected with an anti-slip nut 3 and a piston-type tray 4; the constant resistance device 5 is a resistance pulling mechanism with a pressure-releasing effect. When the pulling force exceeds the internal design resistance, the constant resistance slider 16 drives the threaded rod body 6 to slide, thereby realizing energy absorption and stretching. The constant resistance device 5 includes a constant resistance sleeve 17 with a piston-cylinder structure. The left side of the constant resistance sleeve 17 forms the bottom of the piston-cylinder structure and is fixedly connected to the tail end of the round steel rod 7 via threads. The piston cavity within the constant resistance sleeve 17 is a rough rectangular channel with four walls having a concave-convex rough surface. A matching constant resistance slider 16, acting as a piston, is located within the rough rectangular channel. Movement of the constant resistance slider 16 within the rough rectangular channel requires overcoming a designed frictional resistance. The end of the threaded rod 6 passes through an opening on the right side of the constant resistance sleeve 17 and extends into the rough rectangular channel, connecting with the constant resistance slider 16 to form a piston rod. A spring 19 is provided between the constant resistance slider 16 and the bottom of the piston-cylinder structure of the constant resistance sleeve 17. The spring 19 is secured at both ends by magnets 18 located on the bottom of the piston-cylinder structure and on the constant resistance slider 16. A piston tray 4 and an anti-slip nut 3 are sequentially mounted on the threaded rod 6, where the anchor rod's main body is exposed in the anchor hole 2. The piston tray 4 extends deep into the anchor hole to prevent lateral movement of the anchor rod.

[0030] like Figure 1 and Figure 2 As shown, a method for using a constant resistance absorption and pressure monitoring anchor device is provided.

[0031] Drill an anchor hole 2 at a pre-calibrated position in the surrounding rock 1, and install a fixed steel limiter 12 and an annular grout stopper 9 on the anchor rod body. The limiter 12 is set through the screw hole 24, and a piston tray 4 is installed at the corresponding position. Then, install the linear displacement sensor 11 and the high-strength spring pull rod 8 and fix them with bolts 13. It is necessary to ensure that the high-strength spring 20 in the pull rod is in a free state at this time. Then, send the anchoring agent 10 (clay roll, curing agent roll) and the anchor rod into the anchor hole 2, start the agitator to stir until it is fully stirred. Finally, after the anchoring agent is cured, install the anti-slip wire nut 3 outside the hole.

[0032] Specifically:

[0033] Drill anchor holes 2 at pre-marked locations in the surrounding rock 1, and install fixed steel limiters 12 and annular grout stoppers 9 on the anchor rod body.

[0034] Put the anchoring agent 10 and the anchor rod into the anchor hole 2, start the stirrer to stir until it is fully stirred; the anchoring agent 10 includes a clay roll and a curing agent roll;

[0035] After the anchoring agent solidifies, the anti-slip nut 3 is installed outside the hole. By pre-tightening the anti-slip nut 3, the piston tray 4 is in contact with the rock surface and pressed against the rock surface. At this time, the high-strength spring pull rod 8 will be compressed, and relative displacement will occur between the constant resistance slider 16 and the constant resistance sleeve 17. The linear displacement sensor 11 between the piston tray 4 and the limiter 12 records the data, transmits it to the multi-function instrument, and displays the preload data after calculation based on the spring characteristics.

[0036] When the pre-tightening force is provided along the threaded anchor rod by the pre-tightening anti-slip nut 3, the piston tray 4 is squeezed, and the support resistance provided by the pre-tightening force suddenly changes. The buffer device composed of the high-strength spring pull rod 8, the piston tray 4 and the limit body 12 can share part of the pre-tightening force that should be transmitted to the threaded rod body, thereby improving the stress condition of the anchor rod body. At this time, the constant resistance device 5 and the four high-strength spring pull rods 8 are regarded as a whole, and they work together to resist the harm caused by the instantaneous change of the support resistance, thereby protecting the constant resistance device 5 with poor integrity.

[0037] When the surrounding rock 1 undergoes a large deformation, the piston tray 4 is impacted, causing the constant resistance slider 16 to slide along the concave-convex structure of the inner wall of the constant resistance sleeve 17, causing the rod to stretch and deform. The structural change of the constant resistance device 5 resists the deformation and damage of the rock mass, achieving a pressure relief effect.

[0038] The linear displacement sensor 11 can transmit the slip change data to the multi-function instrument. The slip change is the deformation of the surrounding rock. When the surrounding rock 1 is deformed, the piston tray 4 is impacted, resulting in a sudden change in the support resistance. The tension generated by the high-strength spring pull rod 8 in the buffer device resists the instantaneous change in the support resistance and causes harm. As the surrounding rock deforms, the high-strength spring 20 continues to stretch, generating greater tension to resist the deformation of the surrounding rock and cause damage, thereby preventing the anchor rod from being damaged due to excessive load or absorbing too much energy.

Claims

1. A constant resistance absorption and pressure monitoring anchor device, characterized by: The invention comprises an anchor rod body, wherein the anchor rod body comprises a threaded rod body (6) and a round steel rod body (7), wherein the threaded rod body (6) is connected to the round steel rod body (7) via a constant resistance device (5), and the threaded rod body (6) is threadedly connected with an anti-slip nut (3) and a piston tray (4); the constant resistance device (5) is a resistance pulling mechanism with a pressure-releasing effect, and when the pulling force exceeds the internal design resistance, the constant resistance slider (16) drives the threaded rod body (6) to slide, thereby realizing energy absorption and stretching; The constant resistance device (5) includes a constant resistance sleeve (17) of a piston cylinder structure. The left side of the constant resistance sleeve (17) is the bottom of the piston cylinder structure and is fixedly connected to the tail end of the round steel rod (7) through a thread. The piston cavity in the constant resistance sleeve (17) is a rough rectangular channel. The four walls of the rough rectangular channel are rough surfaces with a concave-convex structure. A constant resistance slider (16) matching the constant resistance slider (16) as a piston is provided in the rough rectangular channel, so that the constant resistance slider (16) needs to overcome the designed friction resistance when moving in the rough rectangular channel. The end of the threaded rod (6) passes through the opening on the right side of the constant resistance sleeve (17) and extends into the rough rectangular channel to connect with the constant resistance slider (16). The resistance slider (16) is connected to form a piston rod, and a spring (19) is provided between the constant resistance slider (16) and the bottom of the piston cylinder structure of the constant resistance sleeve (17). The two ends of the spring (19) are respectively connected to the bottom of the piston cylinder structure and the constant resistance slider (16) through magnets (18). When the surrounding rock deforms and the constant resistance slider (16) overcomes the resistance generated by the mutual extrusion with the rough surface of the concave-convex structure and slides, the spring (19) fixed between the bottom of the piston cylinder structure and the constant resistance slider (16) in a normal state without stress is stretched accordingly, and the tension generated by the stretching of the spring (19) can limit the sliding of the slider (16), so as to prevent the surrounding rock (1) from continuously deforming. The round steel rod body (7) is connected to the constant resistance sleeve (17) and is also threadedly provided with a disc-mounted limiter (12). A buffer device is provided between the limiter (12) and the piston tray (4) and is parallel to the constant resistance device (5). The buffer device is a plurality of high-strength spring pull rods (8). The high-strength spring pull rod (8) includes a hollow steel tube (22). The bottom of the hollow steel tube (22) is fixed to the piston tray (4) by bolts (13) through a base (23). The upper end of the hollow steel tube (22) is fixed to the limiter (12) by bolts (13) through a movable rod (21). A high-strength spring (20) in a tensile state is provided in the hollow steel tube (22). The two ends of the high-strength spring (20) are respectively connected to the bottom of the hollow steel tube (22) and the movable rod (21); Under normal conditions, the high-strength spring (20) in a stretched state enhances the support resistance; when the surrounding rock (1) deforms and causes the high-strength spring pull rod (8) to continue to stretch, the spring elastic force continues to increase, and the resistance provided by the piston-type tray (4) connected to the spring pull rod (8) close to the rock surface will also increase.

2. The constant resistance absorption and yield stress monitoring anchor device according to claim 1, characterized in that: A linear displacement sensor (11) for measuring the sliding distance of the constant resistance slider (16) relative to the constant resistance sleeve (17) in the constant resistance device (5) is also provided between the limiting body (12) and the piston-type tray (4). The linear displacement sensor (11) is connected to a multifunctional instrument (15) via a wire (14). With the help of the data of the linear displacement sensor (11) and the characteristics of the high-strength spring (20) in the high-strength spring pull rod (8), the multifunctional instrument (15) processes the data to realize the monitoring of the anchor rod preload and the surrounding rock deformation.

3. The constant resistance absorption and yield stress monitoring anchor device according to claim 1, characterized in that: The material strength of the constant resistance sleeve (17) is lower than that of the constant resistance slider (16), so it deforms before the constant resistance slider (16). The cross-section of the constant resistance sleeve (17) will be reduced when the material is tensilely deformed. The sliding of the constant resistance slider (16) requires a greater tensile force, and the support effect is enhanced to prevent the constant resistance slider (16) from being damaged by friction due to its lower strength during the sliding process in the constant resistance sleeve (17), thereby reducing the resistance effect. When the surrounding rock (1) is deformed, the piston tray (4) is impacted, causing the constant resistance slider (16) to slide along the rough surface of the concave-convex structure of the inner wall of the constant resistance sleeve (17), causing the rod body to stretch and deform as a whole, thereby resisting the deformation and damage of the rock mass and achieving the pressure-releasing effect. At the same time, the spring (19) in the normal unstressed state inside the constant resistance device (5) can coordinate the sliding deformation of the device. When the surrounding rock is deformed, it is tensile, absorbing the deformation energy of the surrounding rock (1). The tensile force generated can limit the movement of the slider, preventing the constant resistance device (5) from being damaged.

4. The constant resistance absorption and yield stress monitoring anchor device according to claim 1, characterized in that: Under the coordinated buffering action of the high-strength spring pull rod (8), the piston tray (4) and the limiter (12), when the surrounding rock (1) is deformed and the anti-slip wire nut (3) is pre-tightened, resulting in a change in the support resistance, the tension provided by the high-strength spring pull rod (8) resists the damage caused by the instantaneous change in the support resistance, thereby preventing the anchor rod from being damaged due to bearing excessive load or absorbing excessive energy, and also protecting the constant resistance device.

5. The constant resistance absorption and yield stress monitoring anchor device according to claim 1, characterized in that: An annular grouting plug (9) for sealing the anchoring agent (10) is provided on the round steel rod (7).

6. A method for using the constant resistance absorption and pressure yield monitoring anchor device according to any one of claims 1 to 5, characterized in that Here are the steps: Drill anchor holes (2) at pre-marked locations in the surrounding rock (1), install fixed steel limiters (12) and annular grout stoppers (9) on the anchor rod body, The anchoring agent (10) and the anchor rod are placed into the anchor hole (2), and the agitator is started to stir until the mixture is fully stirred; the anchoring agent (10) includes a clay roll and a curing agent roll; After the anchoring agent is solidified, an anti-slip nut (3) is installed outside the hole. By pre-tightening the anti-slip nut (3), the piston tray (4) is brought into contact with the rock surface and pressed against the rock surface. At this time, the high-strength spring pull rod (8) is compressed, and relative displacement occurs between the constant resistance slider (16) and the constant resistance sleeve (17). The linear displacement sensor (11) between the piston tray (4) and the limiter (12) records the data and transmits it to the multi-function instrument to display the preload data after calculation in combination with the spring characteristics. When a pre-tightening force is provided along the threaded anchor rod by the pre-tightening anti-slip nut (3), the piston tray (4) is squeezed, and the support resistance provided by the pre-tightening force suddenly changes. The buffer device composed of the high-strength spring pull rod (8), the piston tray (4) and the limiter (12) can share part of the pre-tightening force that should be transmitted to the threaded rod body, thereby improving the stress condition of the anchor rod body. At this time, the constant resistance device (5) and the four high-strength spring pull rods (8) are regarded as a whole, and they work together to resist the damage caused by the instantaneous change of the support resistance, thereby protecting the constant resistance device (5) with poor integrity.

7. The method of use according to claim 6, characterized in that: When the surrounding rock (1) undergoes a large deformation, the piston tray (4) is impacted, causing the constant resistance slider (16) to slide along the rough surface of the concave-convex structure of the inner wall of the constant resistance sleeve (17) to cause the rod body to extend and deform. Through the structural change of the constant resistance device (5), the deformation and damage of the rock mass are resisted, and the pressure-releasing effect is achieved; The linear displacement sensor (11) can transmit the slip change data to the multifunctional instrument, and the slip change is the deformation of the surrounding rock. When the surrounding rock (1) is deformed, the piston tray (4) is impacted, causing a sudden change in the support resistance. The tensile force generated by the high-strength spring pull rod (8) in the buffer device resists the instantaneous change in the support resistance and causes harm. As the surrounding rock deforms, the high-strength spring (20) continues to stretch, generating a greater tensile force to resist the deformation of the surrounding rock and cause damage, thereby preventing the anchor rod from being damaged due to excessive load or excessive energy absorption.

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