Anchor rod yield and prestress monitoring integrated device and its use method

Abstract

The present invention discloses an anchor rod pressure relief and prestress monitoring system, which belongs to the field of underground engineering support and geotechnical engineering monitoring technology. It includes a steel sleeve, a nitrogen spring, and a pneumatic prestress monitor that is sleeved on the anchor rod. The rear end of the steel sleeve is provided with a steel sleeve flange for resting on the rock mass outside the anchor hole, and the front is provided with a slot for docking with the nitrogen spring. The nitrogen spring has good compression performance and causes the anchor rod to produce a pressure relief effect when the underground engineering rock mass deforms. When prestress is applied, the high-strength gear nut will drive the pneumatic push head of the pneumatic prestress monitor to squeeze the nitrogen in the cylinder of the pneumatic prestress monitor, so that the air pressure value and the prestress value are mutually balanced. The air pressure value will be captured by the pressure sensor and finally passed through a comprehensive data reader to display the anchor rod prestress value in real time according to the nitrogen pressure. It has the advantages of large deformation pressure relief, recyclability, simple and convenient installation, and high monitoring accuracy.

Description

Technical Field

[0001] The invention relates to an integrated device for monitoring anchor rod pressure relief and prestressing force and a use method thereof, belonging to the technical field of underground engineering support and geotechnical engineering monitoring. Background Art

[0002] In recent years, with the rapid development of anchor support technology, research on anchor support theory has also made significant progress. The decisive role of prestressing in anchor support has gradually been recognized. The importance of anchor prestressing has been widely recognized and valued in geotechnical reinforcement engineering. Generally speaking, applying prestressing is the primary measure for anchors to actively support the surrounding rock of underground projects such as roadways, tunnels, and chambers. The greater the applied prestressing, the more conducive it is to the active support effect of the anchor. With the increasing intensity of mineral resource mining and the large-scale construction of deep-ground engineering projects, in the complex and difficult engineering environments of roadways, tunnels, and chambers, there are still engineering and technical difficulties such as the inability to intuitively obtain the applied prestressing value of the anchor and the easy loss of applied prestressing. Therefore, in order to further study the interaction mechanism between the anchor and the surrounding rock and evaluate the safe use status of the anchor, it is necessary to design a more reliable prestressing monitoring and maintenance device for the project.

[0003] Currently, the engineering community lacks sufficient understanding of the effects of anchor prestressing, and a mature and unified theoretical system has yet to be established. Research on prestressed anchors, both domestically and internationally, primarily focuses on the anchoring system and rock reinforcement mechanisms. Relatively little research has been conducted on anchor prestress monitoring and surrounding rock control effectiveness evaluation methods. Currently, torque wrenches, torque amplifiers, anchor installation machines, anchor axial force dynamometers (pressure cells, hydraulic pillows), or bolt deformation are commonly used to determine the magnitude of applied prestress. However, these methods still suffer from issues such as the inability to obtain real-time anchor prestress, low measurement accuracy, and poor reliability, rendering the test results ineffective in guiding anchor support design. Furthermore, large surrounding rock deformation in underground projects can not only offset the applied prestress but also damage the anchor and its monitoring equipment. Consequently, anchor yield structures (devices) have emerged. Currently, anchor yield mechanisms can be categorized as mechanically sliding, using yield tubes (e.g., yield tubes, yield rings), and relying on the yield elongation of the material itself. However, its operability and scalability are poor at the engineering application level and it has certain limitations. Summary of the Invention

[0004] Technical problem: In order to address the shortcomings of the existing technology, an integrated device for anchor rod pressure relief and prestress monitoring and its use method are provided. The device has the advantages of large deformation pressure relief, recyclability, simple and convenient installation, and high monitoring accuracy.

[0005] Technical Solution: To achieve the above technical objectives, the present invention provides an integrated anchor rod pressure relief and prestress monitoring device, which is installed on the anchor rod. The tail of the anchor rod located outside the anchor hole is provided with a high-density threaded section. The tail of the anchor rod is sleeved with a nitrogen spring pressure relief system and a pneumatic prestress monitoring system. The nitrogen spring pressure relief system and the pneumatic prestress monitoring system are connected by a suction cup. The nitrogen spring pressure relief system is provided on the anchor rod section inside the anchor hole, and the pneumatic prestress monitoring system is provided on the high-density threaded section outside the anchor hole.

[0006] The nitrogen spring pressure relief system includes a steel sleeve sleeved on the anchor rod. The front end of the steel sleeve is closed and only has a hole allowing the anchor rod to pass through. The rear end of the steel sleeve is fully open and provided with a flange-shaped steel sleeve flange. The steel sleeve is inserted into the anchor hole, and the rear end of the steel sleeve flange is against the rock wall where the anchor hole is located. A pair of nitrogen springs are provided on both sides of the anchor rod in the steel sleeve. The ends of the nitrogen springs are connected to the inner side of the front end of the steel sleeve. The tail of the nitrogen spring is provided with a self-locking baffle in contact with the air pressure prestressing monitoring system. The self-locking baffle can resist the nitrogen spring protruding outward due to deformation of the surrounding rock, thereby compressing the nitrogen spring and protecting the anchor rod from pressure relief.

[0007] The pneumatic prestressing monitoring system includes a rotatable tray, two cylinders filled with nitrogen, and a high-strength gear nut provided on the high-density threaded section at the tail of the anchor rod. The rotatable tray is a disc structure with a central opening, and the opening of the rotatable tray is connected to the high-density threaded section through a bearing connecting tube. The bottom ends of the two cylinders are symmetrically arranged on the rotating surface of the rotatable tray by bolts, and the other rotating surface of the rotatable tray is connected to the flange of the steel sleeve through a suction cup. A rotating handle is provided between the two cylinders through a crossbeam; all cylinders are provided with a pneumatic push head, and the top of the pneumatic push head is connected to a rigid push rod, which is a special-shaped structure. One end of the rigid push rod is connected to the pneumatic push head, and the other end is connected to the high-strength gear nut by a high-strength bolt; all cylinders are provided with air injection holes, the rigid push rod is provided with a toothed belt, and the cylinder is provided with a small gear that matches the toothed belt to ensure the moving trajectory of the rigid push rod; a tray nut stabilizer is provided between the high-strength gear nut and the rotatable tray to fix the relative position of the high-strength gear nut and the rotatable tray after prestressing is applied;

[0008] All cylinders are equipped with pressure sensors at the bottom, and all pressure sensors are connected to the integrated data readout machine through built-in data cables;

[0009] When the rock mass deforms, the anchor rod produces a compressive effect. When prestress is applied, the high-strength gear nut drives the air pressure push head of the air pressure prestress monitor to squeeze the nitrogen in the cylinder downward, so that the air pressure value of the cylinder is balanced with the prestress value. The air pressure value is obtained by the pressure sensor and finally displayed in real time by the integrated data reader according to the nitrogen pressure.

[0010] Furthermore, the nitrogen spring is a gas piston structure, including a nitrogen cylinder, a cylinder piston head inside the nitrogen cylinder, and a piston transmission rod connected to the cylinder piston head, wherein a groove is provided at the end of the nitrogen cylinder, and a tenon is provided on the inner side of the end of the steel sleeve. The groove at the end of the nitrogen cylinder and the tenon at the end of the steel sleeve are quickly connected, and the self-locking baffle is in contact with the end of the nitrogen spring.

[0011] Furthermore, before using the air pressure prestress monitor, first fill the cylinder with nitrogen at one atmospheric pressure from the air injection hole, use the expansion of nitrogen to slowly push the air pressure push head to the top of the cylinder, adjust the pressure value on the integrated data readout to zero, and then close the air injection hole. Define the pressure sensor at this time as 0.

[0012] Furthermore, after the high-strength gear nut is installed at the tail of the anchor rod, the end of the rigid push rod with a pneumatic push head is fixed to the high-strength gear nut through two high-strength bolts; specifically, the prestressed torque is applied by rotating the handle, and the high-strength gear nut is screwed along the anchor rod toward the rock mass to complete the installation; the inner side of the self-locking baffle is provided with an internal thread matching the high-density thread section, so that it can move on the anchor rod.

[0013] Furthermore, the nitrogen cylinder of the nitrogen spring is filled with nitrogen at atmospheric pressure. Under normal conditions, the nitrogen spring is in a naturally extended and relaxed state, and its total length is consistent with the length of the steel sleeve. When the rock mass is deformed, the rock mass will push the steel sleeve as a whole to displace in the normal direction outside the anchor hole. At this time, the self-locking baffle fixed on the anchor rod squeezes the piston transmission rod of the nitrogen spring to prevent it from continuing to move outward with the steel sleeve. Under the pressure of the steel sleeve, the cylinder piston head will squeeze the nitrogen in the nitrogen cylinder, and the nitrogen spring will contract to alleviate the damage to the anchor rod caused by rock mass deformation.

[0014] Furthermore, the rigid push rod includes a piston rod section which is arranged perpendicular to the cylinder and can move in the cylinder with the pneumatic push head. The end of the piston rod section is connected to a high-strength gear nut connecting section which is arranged parallel to the piston rod section through a connecting section. The end of the high-strength gear nut connecting section is connected to the high-strength gear nut through a high-strength bolt. The high-strength gear nut connecting section is provided with a toothed belt which matches the pinion, so as to facilitate the horizontal displacement of the rigid push rod.

[0015] Furthermore, the contact surface of the rotatable pallet and the steel sleeve flange is connected by multiple suction cups, and the contact surface of the rotatable pallet is connected to the steel sleeve flange of the steel sleeve. The other rotating surface of the rotatable pallet is fixed to the pneumatic prestressed monitor by 4 bolts to achieve synchronous rotation movement.

[0016] Furthermore, a pallet nut stabilizer is arranged between the high-strength gear nut and the rotatable pallet. The pallet nut stabilizer is a length-adjustable structure. The pallet nut stabilizer includes a telescopic rod and a base for mounting the telescopic rod. The base is provided with a length fixing knob. The telescopic rod is used to customize the length of the pallet nut stabilizer, and the length fixing knob is used to fix the position of the telescopic rod. Hooks are provided at the ends of the telescopic rod and the base, which are respectively used to fix on the bolts and high-strength bolts.

[0017] Furthermore, the integrated data reader needs to perform addition calculations on the main electrical signals from the built-in data line. Since the applied prestress and the nitrogen pressure in the cylinder are a pair of balancing forces, the displayed pressure value is the applied prestress value, and the data will change in real time according to the nitrogen pressure in the cylinder. In addition to the integrated data reader, all circuit components are built into the air pressure prestress monitor.

[0018] A method for using an integrated device for monitoring anchor yield and prestressing, characterized by the following steps:

[0019] Step 1: Arrange anchor holes on the rock mass and expand the holes 0.5 to 1.0 m from the ends of the anchor holes to form large installation holes. The size of the large installation holes matches the size of the steel sleeves, so that the steel sleeves are in close contact with the large installation holes and the flanges of the steel sleeves are against the outer wall of the anchor holes.

[0020] Step 2: Place the anchor rod together with the steel sleeve into the anchor hole after the large hole is installed. The outer side of the steel sleeve is in close contact with the rock surface, and the flange of the steel sleeve acts as a tray. Place a pair of nitrogen springs in a relaxed and stretched state between the anchor rod and the steel sleeve, align the tenon with the slot, and fix the self-locking baffle to the exposed end of the anchor rod in the sleeve so that it lightly contacts the piston transmission rod of the nitrogen spring.

[0021] Step 3: Install a rotatable tray on the self-locking baffle and secure the air pressure prestressing monitor to the rotatable tray with bolts; connect the exposed plug of the built-in data cable to the built-in data cable port on the integrated data reader, and operate the integrated data reader to initialize the data;

[0022] Step 4: Open the air injection holes at the top of the two cylinders and inject nitrogen into the cylinders until the air pressure push head is pushed to the top of the cylinder. When the gas pressure value on the integrated data reader reaches zero, stop injecting nitrogen and close the air injection holes. Then, reset the data on the integrated data reader to zero again to prepare for reading new data. Install the high-strength gear nut and use high-strength bolts to fix the end of the rigid push rod to the high-strength gear nut. Then, install the tray nut stabilizer between the high-strength gear nut and the rotatable tray.

[0023] Step 5: Loosen the length fixing knob on the pallet nut stabilizer. At this time, the telescopic rod can freely extend and retract without resistance. Prestress monitoring begins. The machine rotates clockwise to provide prestress torque for the rotating handle. The air pressure prestress monitor rotates. The high-strength gear nut rotates toward the rock mass, driving the air pressure push head to squeeze the nitrogen in the two cylinders, generating pressure. The data is captured by the pressure sensor and transmitted to the integrated data reader. The integrated data reader displays the current prestress value in real time.

[0024] Step 6: Observe the prestress value on the integrated data readout. When the target prestress value is reached, stop applying the prestress torque and tighten the length fixing knob. At this time, the length of the telescopic rod on the pallet nut stabilizer has been fixed. The entire pallet nut stabilizer becomes a rigid top column, stuck between the high-strength gear nut and the rotatable pallet, maintaining the relative position of the two, ensuring that the prestressing effect will not be lost due to the deformation of the rock mass.

[0025] Step 7: After the prestressing is completed, if you want to obtain the prestressing status at any time, you only need to read the numbers displayed on the integrated data reader. The prestressing status and subsequent prestressing loss can be judged through the data displayed on the integrated data reader;

[0026] Step 8: Maintain the overall status of the system until the end of the project, set the display screen of the integrated data reader to automatic screen-off mode to reduce unnecessary energy waste; Taking the above into consideration: through real-time monitoring of anchor rod prestress, dynamic feedback of the actual prestress value of the anchor rod is used to ensure that the prestress condition meets the construction design requirements and avoid safety accidents.

[0027] Beneficial effects: This device has the functions of controlling the early deformation of surrounding rock, monitoring the prestress of anchor rods in real time, and producing large deformation pressure relief, thereby enhancing the reliability of anchor support and the surrounding rock control effect; the size of anchor rod prestress can be obtained in real time, thereby extending the life of the anchor rod and reducing the probability of safety accidents. The prestress measured by this device is described by the pressure change of nitrogen in the two cylinders. The results are reliable and the measurement accuracy is high. With the cooperation of the cylinder bottom pressure sensor and the integrated data reader outside the structure, the difficulty coefficient of workers' operation is reduced, the intuitiveness of the measurement results is enhanced, and the manpower and material costs are greatly saved. All components involved in this device are reusable and can be recycled after the construction is completed and put into use again in the next project. It has the advantages of simple structure, easy operation, high monitoring accuracy, reusability, and good economic benefits. It has wide applicability and promotion in this technical field. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 Schematic diagram of the anchor hole used in the integrated device for monitoring anchor pressure and prestress based on the air pressure principle of the present invention;

[0029] Figure 2 Schematic diagram of the structure of an integrated device for monitoring anchor pressure relief and prestressing based on the air pressure principle in an embodiment of the present invention;

[0030] Figure 3 Schematic diagram of the structure of the nitrogen spring of the present invention;

[0031] Figure 4 This is a schematic structural diagram of the air pressure prestressing monitoring device of the present invention;

[0032] Figure 5 This is a schematic structural diagram of the retractable pallet nut stabilizer of the present invention.

[0033] In the figure: 1-anchor rod, 2-rotating handle, 3-rigid push rod, 4-pneumatic push head, 5-cylinder, 6-toothed belt, 7-air injection hole, 8-integrated data readout device, 9-bolt, 10-steel sleeve flange, 11-rotatable tray, 12-rock mass, 13-steel sleeve, 14-tenon, 15-anchor hole, 16-nitrogen spring, 17-self-locking baffle, 18-tray nut stabilizer, 19-high-strength bolt, 20-built-in data cable, 21-pressure sensor, 22-pinion, 23-high-strength gear nut, 24-high-density thread segment, 25-hook, 26-telescopic rod, 27-length fixing knob, 28-piston transmission rod, 29-cylinder piston head, 30-nitrogen cylinder, 31-slot. DETAILED DESCRIPTION

[0034] The present invention will be further described below with reference to the embodiments in the accompanying drawings:

[0035] The present invention provides an integrated device for anchor bolt pressure relief and prestress monitoring and its use method, which includes a nitrogen spring pressure relief system and a gas pressure prestress monitoring system. The nitrogen spring pressure relief system mainly includes a steel sleeve 13, a nitrogen spring 16 and a self-locking baffle 17 that abuts against the piston transmission rod 28 at the end of the nitrogen spring. Figure 2 and Figure 3 As shown, the anchor rod 1 is covered with a steel sleeve 13 in the open section inside the rock mass 12, and two nitrogen springs 16 are installed in the gap between the sleeve and the anchor rod. When docking, the bottom groove 31 of the spring should be aligned with the bottom tenon 14 of the sleeve. The exposed section of the anchor hole of the anchor rod 1 is provided with a high-density threaded section 24. The self-locking baffle 17 is rotated to a suitable position, just close to the piston transmission rod 28 of the spring. When the rock mass 12 is deformed and drives the anchor rod as a whole to move in the outward normal direction, the fixed self-locking baffle 17 will press the nitrogen spring 16, thereby releasing the pressure-releasing performance of the spring, thereby protecting the anchor rod body and improving its life and durability.

[0036] The nitrogen spring pressure relief system includes a steel sleeve 13 sleeved on the anchor rod 1. The front end of the steel sleeve 13 is closed and only has a hole allowing the anchor rod 1 to pass through. The rear end of the steel sleeve 13 is fully open and provided with a flange-shaped steel sleeve flange 10. The steel sleeve 13 is inserted into the anchor hole 15. The rear end of the steel sleeve flange 10 is against the wall of the rock mass 12 where the anchor hole 15 is located. A pair of nitrogen springs 16 are provided on both sides of the anchor rod 1 in the steel sleeve 13. The ends of the nitrogen springs 16 are connected to the inner side of the front end of the steel sleeve 13. The tail of the nitrogen spring 16 is provided with a self-locking baffle 17 in contact with the air pressure prestressing monitoring system. The self-locking baffle 17 can withstand the nitrogen spring protruding outward due to deformation of the surrounding rock, thereby compressing the nitrogen spring and protecting the anchor rod by pressure relief.

[0037] The pneumatic prestressed load monitoring system includes a rotatable tray 11, two cylinders 5 filled with nitrogen, and a high-strength gear nut 23 provided on a high-density threaded section 24 at the tail of the anchor rod 1. The rotatable tray 11 is a disc structure with a central opening. The opening of the rotatable tray 11 is connected to the high-density threaded section 24 through a bearing connecting pipe. The bottom ends of the two cylinders 5 are symmetrically arranged on the rotating surface of the rotatable tray 11 through bolts 9. The other rotating surface of the rotatable tray 11 is connected to the steel sleeve flange 10 through a suction cup. A rotating handle 2 is provided between the two cylinders 5 through a crossbeam. All cylinders 5 are provided with a pneumatic push rod. Head 4, the top of the pneumatic push head 4 is connected to a rigid push rod 3, the rigid push rod 3 is a special-shaped structure, one end of the rigid push rod 3 is connected to the pneumatic push head 4, and the other end is connected to the high-strength gear nut 23 through a high-strength bolt 19; all cylinders 5 are provided with air injection holes 7, the rigid push rod 3 is provided with a toothed belt 6, and the cylinder 5 is provided with a small gear 22 that matches the toothed belt 6 to ensure the moving trajectory of the rigid push rod 3; a tray nut stabilizer 18 is provided between the high-strength gear nut 23 and the rotatable tray 11, so as to fix the relative position of the high-strength gear nut 23 and the rotatable tray 11 after prestressing;

[0038] All cylinders 5 are provided with pressure sensors 21 at the bottom, and all pressure sensors 21 are connected to the integrated data reader 8 via built-in data cables 20;

[0039] When the rock mass is deformed, the anchor rod 1 produces a pressure-releasing effect. When prestress is applied, the high-strength gear nut 23 drives the air pressure push head 4 of the air pressure prestress monitor to squeeze the nitrogen in the cylinder 5 downward, so that the air pressure value of the cylinder 5 is balanced with the prestress value. The air pressure value is obtained by the pressure sensor 21, and finally the prestress value of the anchor rod 1 is displayed in real time according to the nitrogen pressure through the integrated data reader 8.

[0040] Combine Figure 1 and Figure 2 As shown, a hole is drilled at the designed position of the anchor rod 1, and the anchor hole 15 needs to be enlarged, and the size should meet the placement requirements of the steel sleeve 13.

[0041] like Figure 2 、 Figure 4 and Figure 5 As shown, a method for using an integrated device for monitoring anchor yield and prestressing is as follows:

[0042] Step 1: Arrange anchor holes 15 on the rock mass 12, and expand the holes 0.5 to 1.0 m from the ends of the anchor holes 15 to form large installation holes. The size of the large installation holes matches the size of the steel sleeve 13, so that the steel sleeve 13 is in close contact with the large installation holes and the flange 10 of the steel sleeve is against the outer wall of the anchor hole 15.

[0043] Step 2: Place the anchor rod 1 together with the steel sleeve 13 into the anchor hole 15 after the large hole is installed. The outer side of the steel sleeve 13 is in close contact with the surface of the rock mass 12, and the flange 10 of the steel sleeve acts as a tray. Place a pair of nitrogen springs 16 in a relaxed and stretched state between the anchor rod 1 and the steel sleeve 13, dock the tenon 14 with the slot 31, and fix the self-locking baffle 17 to the exposed end of the anchor rod 1 in the sleeve so that it is in light contact with the piston transmission rod 28 of the nitrogen spring 16.

[0044] Step 3: Install the rotatable tray 11 on the self-locking baffle 17 and fix the air pressure prestressing monitor to the rotatable tray 11 with the bolts 9; connect the exposed part of the built-in data cable 20 to the built-in data cable port on the integrated data reader 8, and operate the integrated data reader 8 to initialize the data;

[0045] Step 4: Open the air injection holes 7 at the top of the two cylinders 5 and inject nitrogen into the cylinders 5 until the air pressure push head 4 is pushed to the top of the cylinder. When the gas pressure value on the integrated data reader 8 reaches zero, stop injecting nitrogen and close the air injection hole 7. Then, reset the data on the integrated data reader 8 to zero again to prepare for reading new data. Install the high-strength gear nut 23, use the high-strength bolt 19 to fix the end of the rigid push rod 3 to the high-strength gear nut 23, and then install the tray nut stabilizer 18 between the high-strength gear nut 23 and the rotatable tray 11.

[0046] Step 5: Loosen the length fixing knob 27 on the tray nut stabilizer 18. At this time, the telescopic rod 26 can freely extend and retract without resistance. Prestress monitoring begins. The machine rotates clockwise to provide prestress torque for the rotating handle 2, rotating the air pressure prestress monitor. The high-strength gear nut 23 rotates toward the rock mass 12, driving the air pressure push head 4 to squeeze the nitrogen in the two cylinders 5, generating pressure. The data is captured by the pressure sensor 21 and transmitted to the integrated data reader 8, which displays the current prestress value in real time.

[0047] Step 6: Observe the prestress value on the integrated data reader 8. When the target prestress value is reached, stop applying the prestress torque and tighten the length fixing knob 27 at the same time. At this time, the length of the telescopic rod 26 on the pallet nut stabilizer 18 has been fixed. The entire pallet nut stabilizer 18 becomes a rigid top column, which is stuck between the high-strength gear nut 23 and the rotatable pallet 11, maintaining the relative position of the two, so that the high-strength gear nut 23 applies a pretightening force to the rotatable pallet 11 and the steel sleeve flange 10 through the pallet nut stabilizer 18, ensuring that the effect of applying the anchor rod prestress will not fail due to the deformation of the rock mass 12.

[0048] Step 7: After the prestressing is completed, if you want to obtain the prestressing status at any time, you only need to read the digital display of the integrated data reader 8. The prestressing status and subsequent prestressing loss can be judged through the data displayed by the integrated data reader 8.

[0049] Step eight, maintain the overall status of the system until the end of the project, set the display screen of the integrated data reader 8 to automatic screen-off mode to reduce unnecessary waste of electricity; based on the above considerations: through real-time monitoring of anchor rod prestress, dynamic feedback of the actual prestress value of the anchor rod is used to ensure that the prestress condition meets the construction design requirements and avoid safety accidents.

[0050] like Figure 2 、 Figure 4 and Figure 5 As shown, before using the pneumatic prestressed load monitoring system, first put the high-strength gear nut 23 on the high-density threaded section 24 of the anchor rod 1 and screw it to a position close to the pallet. Then use four bolts 9 to fix the pneumatic prestressed load monitoring system on the rotatable pallet 11. Next, turn on the integrated data reader 8 and inject compressible nitrogen into the cylinders 5 on both sides through the air injection hole 7 until the nitrogen expands and pushes the air pressure push head 4 to the bottom of the cylinder. When the digital display of the integrated data reader 8 is zero, stop injecting gas and close the air injection hole 7. At this time, rotate the high-strength gear nut 23 in the direction away from the pallet until it contacts the end of the rigid push rod 3 and fix it with two high-strength bolts 19. Finally, place the pallet nut stabilizer 18 between the pallet and the nut, and release the length fixing knob 27 so that the telescopic rod 26 can freely extend and retract without resistance.

[0051] At the start of prestress monitoring, the mechanical handle 2 is twisted clockwise to provide prestress torque, causing the high-strength gear nut 23 to drive the rigid push rod 3 and the pneumatic push head 4 to compress the nitrogen in the two cylinders 5. The change in air pressure is captured by the pressure sensor 21 at the bottom of the cylinder 5. The signal is ultimately transmitted via the built-in data line 20 to the integrated data reader 8 for addition calculation. The sum of the changes in nitrogen pressure in the two cylinders 5 is the applied prestress. When the desired prestress value is reached, the handle 2 is stopped, and the length fixing knob 27 of the tray nut stabilizer 18 is tightened, preventing the telescopic rod 26 from further extension and retraction, forming a rigid stabilizing brace to maintain the relative position between the nut and the tray, preventing the prestress monitoring from failing later due to deformation of the rock mass 12 and outward displacement. After construction is completed, the various devices can be simply removed for reuse.

Claims

1. An integrated device for monitoring anchor yield and prestressing, arranged on an anchor (1), characterized in that: The tail of the anchor rod (1) outside the anchor hole (15) is provided with a high-density threaded section (24), and the tail of the anchor rod (1) is provided with a nitrogen spring pressure relief system and a gas pressure prestressed monitoring system, and the nitrogen spring pressure relief system and the gas pressure prestressed monitoring system are connected via a suction cup, wherein the nitrogen spring pressure relief system is provided on the anchor rod section inside the anchor hole (15), and the gas pressure prestressed monitoring system is provided on the high-density threaded section (24) outside the anchor hole (15); The nitrogen spring pressure relief system includes a steel sleeve (13) sleeved on the anchor rod (1), the front end of the steel sleeve (13) is closed and only has a hole allowing the anchor rod (1) to pass through, the rear end of the steel sleeve (13) is fully open and provided with a flange-shaped steel sleeve flange (10), the steel sleeve (13) is inserted into the anchor hole (15), the rear end of the steel sleeve flange (10) is against the rock mass (12) wall where the anchor hole (15) is located, a pair of nitrogen springs (16) are provided on both sides of the anchor rod (1) in the steel sleeve (13), the end of the nitrogen spring (16) is connected to the inner side of the front end of the steel sleeve (13), and the tail of the nitrogen spring (16) is provided with a self-locking baffle (17) in contact with the air pressure prestressing monitoring system, the self-locking baffle (17) can resist the nitrogen spring protruding outward due to deformation of the surrounding rock, thereby achieving the purpose of compressing the nitrogen spring and protecting the anchor rod; The pneumatic prestressed load monitoring system comprises a rotatable tray (11), two cylinders (5) filled with nitrogen, and a high-strength gear nut (23) provided on a high-density threaded section (24) at the tail of an anchor rod (1). The rotatable tray (11) is a disk structure with a central opening. The opening of the rotatable tray (11) is connected to the high-density threaded section (24) through a bearing connecting pipe. The bottom ends of the two cylinders (5) are symmetrically arranged on the rotating surface of the rotatable tray (11) through bolts (9). The other rotating surface of the rotatable tray (11) is connected to a steel sleeve flange (10) through a suction cup. A rotating handle (2) is provided between the two cylinders (5) through a crossbeam. A pneumatic push head (4) is provided in all cylinders (5). A rigid push rod (3) is connected to the top of the pneumatic push head (4), and the rigid push rod (3) is a special-shaped structure. One end of the rigid push rod (3) is connected to the pneumatic push head (4), and the other end is connected to the high-strength gear nut (23) through a high-strength bolt (19); all cylinders (5) are provided with air injection holes (7), a toothed belt (6) is provided on the rigid push rod (3), and a small gear (22) is provided on the cylinder (5) to match the toothed belt (6) to ensure the moving trajectory of the rigid push rod (3); a tray nut stabilizer (18) is provided between the high-strength gear nut (23) and the rotatable tray (11), so as to fix the relative position of the high-strength gear nut (23) and the rotatable tray (11) after the prestress is applied; All cylinders (5) are provided with pressure sensors (21) at the bottom, and all pressure sensors (21) are connected to a comprehensive data reader (8) via built-in data cables (20); When the rock mass is deformed, the anchor rod (1) produces a compressive effect. When prestress is applied, the high-strength gear nut (23) drives the air pressure push head (4) of the air pressure prestress monitor to squeeze the nitrogen in the cylinder (5) downward, so that the air pressure value of the cylinder (5) is balanced with the prestress value. The air pressure value is obtained by the pressure sensor (21) and finally displayed in real time by the integrated data reader (8) according to the nitrogen pressure.

2. The integrated device for monitoring anchor yield and prestressing according to claim 1, characterized in that: The nitrogen spring (16) is a gas piston structure, comprising a nitrogen cylinder (30), a cylinder piston head (29) in the nitrogen cylinder (30), and a piston transmission rod (28) connected to the cylinder piston head (29), wherein a groove (31) is provided at the end of the nitrogen cylinder (30), and a tenon (14) is provided on the inner side of the end of the steel sleeve (13), the groove (31) at the end of the nitrogen cylinder (30) and the tenon (14) at the end of the steel sleeve (13) are quickly connected, and a self-locking baffle (17) contacts the end of the nitrogen spring (16).

3. The integrated device for monitoring anchor yield and prestressing according to claim 1, characterized in that: Before using the air pressure prestress monitor, first fill the cylinder (5) with nitrogen gas at atmospheric pressure from the air injection hole (7), and use the expansion of nitrogen to slowly push the air pressure push head (4) to the top of the cylinder. After adjusting the pressure value on the integrated data reader (8) to zero, close the air injection hole (7), and define the pressure sensor at this time as 0.

4. The integrated device for monitoring anchor yield and prestressing according to claim 1, characterized in that: After the high-strength gear nut (23) is installed at the tail end of the anchor rod (1), the end of the rigid push rod (3) with the air pressure push head (4) at the head is fixed together with the high-strength gear nut (23) through two high-strength bolts (19); specifically, by rotating the handle (2) to apply prestressed torque, the high-strength gear nut (23) is screwed along the anchor rod (1) toward the rock mass (12) and the installation is completed; the inner side of the self-locking baffle (17) is provided with an internal thread matching the high-density thread section (24), so that it can move on the anchor rod (1).

5. The integrated device for monitoring anchor yield and prestressing according to claim 1, characterized in that: The nitrogen cylinder (30) of the nitrogen spring (16) is filled with nitrogen at atmospheric pressure. The nitrogen spring (16) is in a naturally stretched and relaxed state in a normal state, and its total length is consistent with the length of the steel sleeve (13). When the rock mass (12) is deformed, the rock mass (12) will push the steel sleeve (13) as a whole to move in the direction of the outer normal of the anchor hole (15). At this time, the self-locking baffle (17) fixed on the anchor rod (1) squeezes the piston transmission rod (28) of the nitrogen spring (16) to prevent it from continuing to move outward with the steel sleeve (13). Under the pressure of the steel sleeve (13), the cylinder piston head (29) squeezes the nitrogen in the nitrogen cylinder (30), and the nitrogen spring (16) contracts to alleviate the damage to the anchor rod (1) caused by the deformation of the rock mass (12).

6. The integrated device for monitoring anchor yield and prestressing according to claim 1, characterized in that: The rigid push rod (3) includes a piston rod section arranged perpendicular to the cylinder (5) and capable of moving in the cylinder (5) along with the pneumatic push head (4), the end of the piston rod section is connected to a high-strength gear nut connecting section arranged parallel to the piston rod section through a connecting section, the end of the high-strength gear nut connecting section is connected to the high-strength gear nut (23) through a high-strength bolt (19), and a toothed belt (6) matching the pinion (22) is provided on the high-strength gear nut connecting section to facilitate horizontal displacement of the rigid push rod (3).

7. The integrated device for monitoring anchor yield and prestressing according to claim 1, characterized in that: The contact surface of the rotatable tray (11) and the steel sleeve flange (10) is connected via a plurality of suction cups, the contact surface of the rotatable tray (11) is connected to the steel sleeve flange (10) of the steel sleeve (13), and the other rotating surface of the rotatable tray (11) is fixed to the pneumatic prestress monitor via four bolts (9) to achieve synchronous rotation.

8. The integrated device for monitoring anchor yield and prestressing according to claim 1, characterized in that: A pallet nut stabilizer (18) is provided between the high-strength gear nut (23) and the rotatable pallet (11). The pallet nut stabilizer (18) is a length-adjustable structure. The pallet nut stabilizer (18) includes a telescopic rod (26) and a base for mounting the telescopic rod (26). A length fixing knob (27) is provided on the base. The telescopic rod (26) is used to customize the length of the pallet nut stabilizer (18). The length fixing knob (27) is used to fix the position of the telescopic rod (26). Hooks (25) are provided at the ends of the telescopic rod (26) and the base, respectively, for fixing on the bolt (9) and the high-strength bolt (19).

9. The integrated device for monitoring anchor yield and prestressing according to claim 1, characterized in that: The integrated data reader (8) needs to perform addition calculation on the main circuit electrical signal from the built-in data line (20). Since the applied prestress and the nitrogen pressure in the cylinder (5) are a pair of balancing forces, the pressure value displayed is the applied prestress value, and the data will change in real time according to the nitrogen pressure in the cylinder (5). Except for the integrated data reader (8), all circuit components are built into the air pressure prestress monitor.

10. A method for using the integrated device for monitoring anchor yield and prestressing according to any one of claims 1 to 9, characterized in that Here are the steps: Step 1: Arrange an anchor hole (15) on the rock mass (12), expand the end of the anchor hole (15) at 0.5 to 1.0 m to form a large installation hole, and match the size of the large installation hole with the size of the steel sleeve (13), so that the steel sleeve (13) is in close contact with the large installation hole, and ensure that the steel sleeve flange (10) is against the outer wall of the anchor hole (15); Step 2: Place the anchor rod (1) together with the steel sleeve (13) into the anchor hole (15) after the large hole is installed, with the outer side of the steel sleeve (13) in close contact with the surface of the rock mass (12), and the flange (10) of the steel sleeve plays the role of a tray; place a pair of nitrogen springs (16) in a relaxed and stretched state between the anchor rod (1) and the steel sleeve (13), dock the tenon (14) with the slot (31), and fix the self-locking baffle (17) to the exposed end of the anchor rod (1) in the sleeve so that it is lightly in contact with the piston transmission rod (28) of the nitrogen spring (16); Step 3: Install the rotatable tray (11) on the self-locking baffle (17), and fix the air pressure prestressing monitor to the rotatable tray (11) through the bolts (9); connect the exposed part plug of the built-in data cable (20) to the built-in data cable port on the integrated data reader (8), and operate the integrated data reader (8) to initialize the data; Step 4: Open the air injection holes (7) at the top of the two cylinders (5) and inject nitrogen into the cylinders (5) until the air pressure push head (4) is pushed to the top of the cylinder and the gas pressure value on the integrated data reader (8) is zero, stop injecting nitrogen and close the air injection holes (7), and then reset the data on the integrated data reader (8) to zero again to prepare for the next reading of new data; install the high-strength gear nut (23), use the high-strength bolt (19) to fix the end of the rigid push rod (3) to the high-strength gear nut (23), and then install the tray nut stabilizer (18) between the high-strength gear nut (23) and the rotatable tray (11); Step 5: Loosen the length fixing knob (27) on the tray nut stabilizer (18), and the telescopic rod (26) can be freely extended and retracted without resistance; the prestress monitoring starts, the machine provides prestress torque for the rotating handle (2) in a clockwise direction, rotates the air pressure prestress monitor, and the high-strength gear nut (23) rotates toward the rock mass (12), driving the air pressure push head (4) to squeeze the nitrogen in the two cylinders (5), generating pressure. The data is captured by the pressure sensor (21) and transmitted to the integrated data reader (8), and the integrated data reader (8) displays the current prestress value in real time; Step 6: Observe the prestress value on the integrated data reader (8). When the target prestress value is reached, stop applying the prestress torque and tighten the length fixing knob (27). At this time, the length of the telescopic rod (26) on the tray nut stabilizer (18) is fixed. The entire tray nut stabilizer (18) becomes a rigid top column, which is stuck between the high-strength gear nut (23) and the rotatable tray (11), maintaining the relative position between the two, and ensuring that the effect of applying the prestress will not fail due to the deformation of the rock mass (12); Step 7: After the prestressing is completed, if you want to obtain the prestressing condition at any time, you only need to read the digital display of the integrated data reader (8). The prestressing condition and the subsequent prestressing loss condition can be judged by the data displayed by the integrated data reader (8); Step 8: Maintain the overall state of the system until the project is completed, and set the display screen of the integrated data reader (8) to automatic off-screen mode to reduce unnecessary power waste.

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