A device for monitoring anchor rod prestress using ultrasonic spring and its use method

Abstract

The present invention discloses a device for monitoring anchor rod prestress using an ultrasonic spring and a method for using the device, which belongs to the fields of tunnel and underground engineering support and geotechnical engineering monitoring technology. The device comprises a high-strength gear nut that fits over the tail of the anchor rod, an ultrasonic spring prestress monitor, a retractable tray nut stabilizer, and a tray. The tail of the anchor rod is provided with a high-density threaded section whose thread density matches the internal thread of the high-strength gear nut. The ultrasonic spring prestress monitor is installed between the tray and the high-strength gear nut. During the application of prestress, the high-strength gear nut squeezes the built-in compression spring, balancing the prestress with the spring's internal force. The ultrasonic rangefinder measures the prestress based on the change in spring displacement, and the result is intuitively displayed by a comprehensive data reader, achieving the purpose of real-time monitoring of the anchor rod's prestress state. The device is recyclable and reusable, and is easy to install, highly precise, reusable, and economically efficient.

Description

Technical Field

[0001] The invention relates to a device for monitoring anchor rod prestress using an ultrasonic spring and a use method thereof, belonging to the field of tunnel and underground engineering support and geotechnical engineering monitoring technology. Background Art

[0002] Roadways are essential passageways for underground coal mining. Ensuring smooth and stable roadways is a prerequisite for safe and efficient coal mining. Underground roadway support has evolved from timber support, masonry support, steel support, to anchor bolting. Anchor bolting has evolved from low-strength and high-strength to highly prestressed and powerful support. Early anchor bolts primarily included mechanical anchor bolts, wire rope mortar anchor bolts, end-anchored resin anchor bolts, rapid-hardening cement anchor bolts, and pipe-slit anchor bolts. These anchor bolts offered low strength and stiffness, and were still passive in principle, resulting in poor support effectiveness. New technologies, materials, and methods, such as extended or full-length resin-anchored high-strength threaded steel anchor bolts, support designs based on geomechanical testing, and prestressed anchor cables, have been widely adopted in many mining areas, achieving excellent support effectiveness and economic benefits. With increasing roadway depths, increasingly complex geological conditions, and intense mining activity, high-strength anchor bolting has gradually exposed numerous problems. In deep and complex tunnels, high-strength anchor support causes large deformation of the surrounding rock, severe damage to support components, and poor support effect, which cannot meet the requirements of safe production. To solve the technical difficulties in supporting tunnels in deep and complex conditions, high-prestressed, high-strength anchor support technology has been developed. Emphasis is placed on the strength of the anchor, the stiffness of the support system, and the importance of anchor prestress, achieving active and timely support of the anchor, giving full play to the supporting role of the anchor, and fundamentally changing the tunnel support and safety conditions. The modern anchor support design concept of "three highs and one low" of high strength, high stiffness, high reliability, and low support density has been realized. While ensuring the support effect, the tunnel excavation speed and work efficiency have been significantly improved.

[0003] With the rapid development and widespread application of anchor support technology, a deeper and more comprehensive understanding of the nature of anchor support has been achieved. The current anchor support theory is: passively suspending coal and rock masses within the range of damage or potential damage; forming a certain structure (beam, layer, arch, shell, etc.) within the anchoring area; improving the mechanical properties and stress state of the surrounding rock in the anchoring area, and controlling the deformation and damage of the surrounding rock. Through continuous in-depth research, it has been found that immediate support after tunnel excavation and the application of a sufficiently high installation force, namely anchor prestressing, are very important for improving the stiffness of the anchor body. Anchor prestressing and its diffusion play a decisive role in the support effect. Determining and ensuring the application of reasonable prestressing and its effective diffusion are the keys to support design. How to accurately obtain the prestress of the serving anchor in real time has always been a difficult problem that has plagued the engineering community. The research and development of anchor prestressing monitoring devices (equipment) and monitoring methods are relatively lagging, which has seriously restricted the promotion and application of anchor support technology.

[0004] No existing detection sensor has a shape that meets the above requirements. At the same time, sensors that lack a certain symmetrical shape are bound to have an uneven force contact surface, which can easily cause uneven force. There was once an idea to place two sensors symmetrically to solve the problem of uneven force, but the placement position and method will still cause large errors in the measurement results. Moreover, if the anchor rod is anchored upside down on the top surrounding rock, the sensor is likely to be damaged due to slipping during disassembly, which is inconvenient.

[0005] At present, mechanical wrenches, torque amplifiers, anchor installation machines, anchor axial force dynamometers and other methods are often used to estimate the size of the prestress applied to the anchor. However, these conventional methods can neither obtain the size of the anchor prestress in real time nor have technical problems such as low measurement accuracy and poor reliability. As a result, the test results are not very instructive for anchor support design. Summary of the Invention

[0006] Technical problem: In view of the shortcomings of the existing technology, a device for monitoring the prestress of anchor rods using ultrasonic springs and a method for using the device are provided. The device has the advantages of high precision, strong reliability, reusability, low production cost, simple operation and easy construction.

[0007] Technical Solution: The present invention provides a device for monitoring anchor prestress using an ultrasonic spring, which is installed at the tail end of the anchor and includes a tray for arranging the anchor outside the rock mass and a high-strength gear nut in a circular structure. An ultrasonic spring prestress monitor is provided between the tray and the high-strength gear nut, as well as a tray nut stabilizer that fixes the distance between the high-strength gear nut and the tray to prevent outward deformation of the rock mass from damaging the prestress measurement value and application effect.

[0008] The ultrasonic spring prestress monitor includes a rectangular polymer shell with a through hole in the middle of the polymer shell for accommodating the anchor rod. The through hole allows the ultrasonic spring prestress monitor to be directly mounted on the anchor rod. A spring pedal is provided in the polymer shell, and a compression spring is provided in the spring pedal. The compression spring is provided with an ultrasonic rangefinder for measuring the change in compression after being subjected to force. The ultrasonic rangefinder is connected to an integrated data reader via a built-in data cable. The ultrasonic rangefinder reads the relative displacement / spring compression of the compression spring, and then the prestress value is calculated by the integrated data reader. The spring pedal includes a gear, and component one and component two are respectively provided on the upper and lower sides of the gear. Component one and component two are both provided with a transmission belt that matches the gear and is linked to the gear. A compression spring is provided between component one and component two, so as to ensure that component one and component two move toward each other along the gear under the action of an external force and squeeze the compression spring between the two. Component one and component two are both provided with ultrasonic rangefinders at the connection points with both ends of the compression spring, which can detect the relative distance between component one and component two in real time, and read the pressure data of the compression spring in real time through a comprehensive data reader.

[0009] The high-strength gear nut is in contact with component one. When a prestressed torque is applied to the high-strength gear nut, the high-strength gear nut generates an extrusion force on component one. Component one is displaced toward component two through the gear and driven by the transmission belt. During the displacement process, the compression spring between component one and component two generates an internal force. At this time, the internal force of the compression spring is balanced with the applied prestress and the values ​​are equal. The purpose of measuring the prestress is achieved by reading the state of the compression spring.

[0010] Furthermore, a high-density thread section is provided at the tail of the anchor rod, and the high-strength gear nut is rotatably fixed to the tail of the anchor rod through the high-density thread section.

[0011] Furthermore, since there is a retractable ultrasonic rangefinder between the high-strength gear nut and the pallet, in order to prevent the pallet from squeezing the monitor under the push of the rock mass when the surrounding rock undergoes external normal deformation, causing the prestress monitoring value to suddenly increase and cause a serious engineering accident; therefore, a pallet nut stabilizer is set between the pushing pallet and the high-strength gear nut to maintain the prestressing effect between the pushing pallet and the high-strength gear nut unchanged, the pallet nut stabilizer includes a telescopic rod with adjustable middle length, and a length fixing knob for adjusting its length is provided in the middle of the telescopic rod. The non-retractable end on one side of the telescopic rod is connected to the high-strength gear nut by a high-strength bolt; the non-retractable end on the other side is connected to the pallet by a high-strength bolt; the pallet nut stabilizer is installed after the prestressing is completed, which can prevent the prestressing failure caused by the external normal deformation of the rock body, and at the same time ensure the measurement accuracy of the prestressing.

[0012] Furthermore, in the ultrasonic spring prestress monitor, the prestress σ transmitted to component one by the high-strength gear nut is positively correlated with the compression Δx of the compression spring, σ∝Δx. The compression Δx is measured by an ultrasonic rangefinder placed between the compression springs. The built-in data line transmits the signal to the integrated data reader. After calculation by the corresponding formula, it is converted into a prestress value and displayed on the screen. The specific correspondence between the prestress value σ and the spring compression Δx is: Where k is the elastic coefficient of the compression spring, D is the diameter of the high-strength gear nut, and d is the diameter of the anchor rod.

[0013] Furthermore, the ultrasonic spring prestress monitor includes gears, component one, component two, compression spring, ultrasonic rangefinder and integrated data reader, which are all arranged in the shell. The prestress value of the integrated data reader is displayed through a screen set on the shell, and the prestress value data will change in real time according to the condition of the compression spring.

[0014] A method for using a device for monitoring anchor rod prestress using an ultrasonic spring, comprising the following steps:

[0015] Step 1: Arrange anchor holes at target locations on the rock mass;

[0016] Step 2: Place the anchor rod into the anchor hole, place the tray to press the rock wall outside the anchor hole, and play its role; put the ultrasonic spring prestressing monitor on the anchor rod, and manually return the second component to the bottom of the polymer material shell. At this time, the first component also moves freely to the initial position driven by the gears and their respective transmission belts;

[0017] Step 3: Put the high-strength gear nut onto the high-density thread section of the anchor rod, and use the corresponding machine to apply prestressing torque to the high-strength gear nut, so that it is screwed clockwise toward the rock mass until the high-strength gear nut lightly contacts the component of the ultrasonic spring prestressing monitor, and then stop applying the prestressing torque;

[0018] Step 4: Turn on the ultrasonic rangefinder to initialize the data. The ultrasonic rangefinder will check the distance between the compression spring of component one and component two at a preset frequency. Given the ultrasonic wave velocity, the integrated data reader calculates the initial distance x0 between the two ends of the compression spring when it is not prestressed, and records the position. Then, the corresponding machinery continues to apply prestress torque to the high-strength gear nut, allowing it to continue to rotate toward the rock mass. At this time, the built-in data cable connected to the ultrasonic rangefinder continuously transmits data to the integrated data reader at a predetermined frequency, displaying the current prestress value in real time.

[0019] Step 5: Watch the prestress value displayed on the integrated data reader. When the required value is reached, stop applying the prestress moment, then record the final position x1, and calculate the value according to the formula: Δx = x0-x1. Calculate the final prestressing value;

[0020] Step 6. After the prestressing force is no longer required, install the pallet nut stabilizer between the high-strength gear nut and the pallet, loosen the length fixing knob, adjust the telescopic rod to the appropriate position, and then tighten the length fixing knob again. Install two high-strength bolts, the first one to fix the high-strength gear nut and the telescopic rod together, and the second one to fix the pallet and the non-telescopic end together. At this time, the length of the telescopic rod on the pallet nut stabilizer has been fixed, and the entire pallet nut stabilizer has become a rigid top column, which is stuck between the high-strength gear nut and the pallet, fixing the relative position of the two, and ensuring that the effect of the prestressing force will not fail due to the deformation of the rock mass.

[0021] Step seven: maintain the overall status 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; when you need to understand the prestressed state again, just turn on the digital display on the integrated data reader.

[0022] Beneficial effects: This device has the effect of controlling the deformation of the surrounding rock and monitoring the prestress of the anchor rod in real time; the size of the 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 change in spring compression, and the result is reliable and the measurement accuracy is high. With the help of the ultrasonic rangefinder inside the instrument, 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; the combination of compression spring and ultrasonic rangefinder used is low-cost, economical and practical, and can provide appropriate reaction force and buffering effect, is not easy to damage, and serves the purpose of protecting the anchor rod; all components involved in this device are reusable and can be recycled after the construction is completed, and can be put into use again in subsequent projects. 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

[0023] Figure 1 A schematic diagram of an anchor hole used in the device for monitoring anchor rod prestressing with an ultrasonic spring according to the present invention;

[0024] Figure 2 Schematic diagram of the structure of an ultrasonic spring prestress monitor in an embodiment of the present invention;

[0025] Figure 3 This is a schematic structural diagram of the retractable pallet nut stabilizer of the present invention.

[0026] In the figure: 1-high-density threaded section, 2-high-strength gear nut, 3-gear, 4-transmission toothed belt, 5-compression spring, 6-component 2, 7-tray, 8-rock mass, 9-anchor rod, 10-anchor hole, 11-polymer material housing, 12-built-in data cable, 13-ultrasonic rangefinder, 14-integrated data reader, 15-tray nut stabilizer, 16-component 1, 17-high-strength bolt, 18-telescopic rod, 19-length fixing knob, 20-non-telescopic end. DETAILED DESCRIPTION

[0027] The present invention will be further described below with reference to the embodiments in the accompanying drawings:

[0028] The present invention relates to a device for monitoring anchor bolt prestress using an ultrasonic spring, wherein the ultrasonic spring prestress monitor mainly comprises a component 16, a gear 3, a transmission belt 4, an ultrasonic rangefinder 13, a compression spring 5, a component 2 6, an integrated data reader 14 and a polymer material housing 11 wrapped therein. Figure 1 and Figure 2 As shown, the anchor rod 9 is inserted into the rock mass 8, the tray 7 is placed on the exposed section of the anchor rod 9 in the rock mass 8, close to the rock wall, the ultrasonic spring prestress monitor is placed on the anchor rod, and the second component 6 is manually reset to the bottom 11 of the polymer material housing. At this time, the first component 16 is also driven by the gear 3 and the respective transmission belts 4 to move freely to the initial position; it includes a tray 7 and a high-strength gear nut 2 with a circular structure, in which the anchor rod 9 is arranged outside the rock mass 8. The ultrasonic spring prestress monitor is provided between the tray 7 and the high-strength gear nut 2, and a tray nut stabilizer 15 is used to fix the distance between the high-strength gear nut 2 and the tray 7 to prevent the rock mass 8 from deforming outward and damaging the prestress measurement value and application effect.

[0029] The ultrasonic spring prestress monitor includes a rectangular polymer housing 11, a through hole is provided in the middle of the polymer housing 11 to accommodate the anchor rod 9, and the through hole is used to directly cover the ultrasonic spring prestress monitor on the anchor rod 9. A spring pedal is provided in the polymer housing 11, and a compression spring 5 is provided in the spring pedal. The compression spring 5 is provided with an ultrasonic rangefinder 13 for measuring the change in compression after the compression spring is subjected to force. The ultrasonic rangefinder 13 is connected to an integrated data reader 14 via a built-in data line 12. The ultrasonic rangefinder 13 reads the relative displacement / spring compression of the compression spring 5, and then calculates the prestress value through the integrated data reader 14; the spring The pedal includes a gear 3, with a first component 16 and a second component 6 provided on the upper and lower sides of the gear 3, respectively. Each of the first component 16 and the second component 6 is provided with a transmission belt 4 that matches the gear 3 and is linked to the gear 3. A compression spring 5 is provided between the first component 16 and the second component 6, thereby ensuring that the first component 16 and the second component 6 move toward each other along the gear 3 under the action of an external force, thereby squeezing the compression spring 5 between the two. Ultrasonic rangefinders 13 are provided at the connection points between the first component 16 and the second component 6 and the ends of the compression spring 5, which can detect the relative distance between the first component 16 and the second component 6 in real time and read the pressure data of the compression spring 5 in real time through an integrated data reader 14.

[0030] The high-strength gear nut 2 is in contact with component 16. When a prestressed torque is applied to the high-strength gear nut 2, the high-strength gear nut 2 generates an extrusion pressure on component 16. Component 1 16 is displaced toward component 2 6 through gear 3 and driven by the transmission belt 4. During the displacement process, the compression spring 5 between component 16 and component 2 6 generates an internal force. At this time, the internal force of the compression spring 5 is balanced with the applied prestress and the values ​​are equal. The purpose of measuring the prestress is achieved by reading the state of the compression spring 5.

[0031] like Figure 1 and Figure 2As shown, the high-strength gear nut 2 is put on the high-density thread section 1 of the anchor rod 9, and the corresponding machine applies a prestressing torque to the high-strength gear nut 2, so that it is screwed in the direction of the rock mass 8 in a clockwise direction until the high-strength gear nut 2 lightly contacts the component 1 16 of the ultrasonic spring prestressing monitor, and then the application of the prestressing torque is stopped; the ultrasonic rangefinder 13 is turned on to initialize the data; the ultrasonic rangefinder 13 will check the distance between the compression spring 5 between the component 1 16 and the component 2 6 according to the preset frequency, and under the condition of the ultrasonic wave velocity, the integrated data reader 14 measures the distance between the component 1 16 and the component 2 6 without being subjected to the ultrasonic wave velocity. During prestressing, the initial distance x0 between the two ends of the compression spring 5 is recorded, and then the corresponding machinery is used to apply prestressing torque to the high-strength gear nut 2, allowing it to continue to rotate toward the rock mass 8. At this time, the built-in data line 12 connected to the ultrasonic rangefinder 13 continuously transmits data to the integrated data reader 14 according to the frequency, and displays the current prestressing value in real time; watching the prestressing value displayed on the integrated data reader 14, when it reaches the engineering requirement value, stop applying the prestressing torque, then record the final position x1, and according to the formula: Δx = x0-x1 and Calculate the final prestressing value;

[0032] like Figure 1 and Figure 3 Install the pallet nut stabilizer 15, loosen the length fixing knob 19, adjust the telescopic rod 18 to the appropriate position and then re-tighten the length fixing knob 19; at this time, the length 18 of the telescopic rod on the pallet nut stabilizer 15 has been fixed, and the entire pallet nut stabilizer 15 has become a rigid top column, which is stuck between the high-strength gear nut 2 and the pallet 7, fixing the relative position of the two to ensure that the effect of prestressing will not fail due to the deformation of the rock mass 8; maintain the overall state of the system until the end of the project, and set the display screen of the integrated data reader 14 to automatic screen-off mode to reduce unnecessary waste of electricity. When you need to understand the prestressed state again, just turn on the digital display on the integrated data reader 14; take comprehensive consideration of the above situation: through real-time monitoring of the anchor rod prestress, dynamic feedback of the actual prestress of the anchor rod is used to ensure that the prestressed state meets the construction design requirements and avoid safety accidents;

[0033] A method for using a device for monitoring anchor rod prestress using an ultrasonic spring, comprising the following steps:

[0034] Step 1: Arrange anchor holes (10) at target locations on the rock mass (8);

[0035] Step 2: Place the anchor rod (9) into the anchor hole (10), place the tray (7) to press the outer rock wall of the anchor hole (10) to play its role; put the ultrasonic spring prestressing monitor on the anchor rod (9), and manually return the second component (6) to the bottom of the polymer material shell (11). At this time, the first component (16) is also driven by the gear (3) and the respective transmission belts (4) to move freely to the initial position;

[0036] Step 3: Put the high-strength gear nut (2) onto the high-density thread section (1) of the anchor rod (9), and use the corresponding machine to apply prestressing torque to the high-strength gear nut (2), so that it is screwed in clockwise toward the rock mass (8) until the high-strength gear nut (2) lightly contacts the component 1 (16) of the ultrasonic spring prestressing monitor. It is only necessary to ensure that the ultrasonic spring prestressing monitor does not loosen between the high-strength gear nut (2) and the tray (7), and then stop applying the prestressing torque;

[0037] Step 4: Turn on the ultrasonic rangefinder (13) to initialize the data; the ultrasonic rangefinder (13) will check the distance between the compression spring (5) of the component 1 (16) and the component 2 (6) at a preset frequency. Under the condition of the ultrasonic wave velocity, the integrated data reader (14) calculates the initial distance x0 between the two ends of the compression spring (5) when it is not prestressed, and records the position. Then, the corresponding machinery is continued to apply prestress torque to the high-strength gear nut (2), allowing it to continue to rotate toward the direction of the rock mass (8). At this time, the built-in data line (12) connected to the ultrasonic rangefinder (13) continuously transmits data to the integrated data reader (14) at a frequency, and displays the current prestress value in real time.

[0038] Step 5: Observe the prestress value displayed on the integrated data reader (14). When the prestress value reaches the engineering requirement value or the preset detection time of the engineering is reached, stop applying the prestress torque, then record the final position x1, and calculate according to the formula: Calculate the final prestressing value;

[0039] Step 6, after the prestress is no longer required to be measured, the pallet nut stabilizer (15) is installed between the high-strength gear nut (2) and the pallet (7), the length fixing knob (19) is loosened, the telescopic rod (18) is adjusted to a suitable position and the length fixing knob (19) is tightened again, and two high-strength bolts (17) are installed, the first one fixes the high-strength gear nut (2) and the telescopic rod (18) together, and the second one fixes the pallet (7) and the non-telescopic end (20) together, so that the high-strength gear nut (2) directly applies sufficient prestress to the pallet (7); at this time, the length of the telescopic rod (18) on the pallet nut stabilizer (15) has been fixed, and the entire pallet nut stabilizer (15) becomes a rigid top column stuck between the high-strength gear nut (2) and the pallet (7), fixing the relative position of the two, and ensuring that the effect of applying the prestress will not fail due to the deformation of the rock mass (8);

[0040] Step 7: Maintain the overall state until the project is completed, set the display screen of the integrated data reader (14) to automatic off-screen mode to reduce unnecessary waste of electricity; when it is necessary to understand the prestressed state again, just turn on the digital display on the integrated data reader (14).

[0041] After the project is completed, you only need to dismantle each device to achieve the purpose of reuse.

Claims

1. A device for monitoring anchor rod prestress using an ultrasonic spring, arranged at the tail end of the anchor rod (9), characterized in that: The invention comprises a tray (7) and a high-strength gear nut (2) having a circular ring structure, wherein an anchor rod (9) is arranged outside the rock mass (8); an ultrasonic spring prestress monitor is provided between the tray (7) and the high-strength gear nut (2); and a tray nut stabilizer (15) for fixing the distance between the high-strength gear nut (2) and the tray (7) and preventing the rock mass (8) from deforming outwards and causing damage to the prestress measurement value and the applied effect; The ultrasonic spring prestress monitor includes a polymer housing (11) of a rectangular structure, a through hole for accommodating an anchor rod (9) passing through the middle of the polymer housing (11), and the ultrasonic spring prestress monitor is directly mounted on the anchor rod (9) by utilizing the through hole. A spring pedal is provided in the polymer housing (11), a compression spring (5) is provided in the spring pedal, and an ultrasonic rangefinder (13) is provided on the compression spring (5) for measuring the change in compression after the compression spring (5) is subjected to force. The ultrasonic rangefinder (13) is connected to an integrated data reader (14) via a built-in data line (12), and the ultrasonic rangefinder (13) reads the relative displacement / spring compression of the compression spring (5), and then calculates the prestress value through the integrated data reader (14); the spring pedal includes a gear (3), The upper and lower sides of the gear (3) are respectively provided with a component one (16) and a component two (6), and a transmission toothed belt (4) matching the gear (3) is provided on the component one (16) and the component two (6) to be linked with the gear (3). A compression spring (5) is provided between the component one (16) and the component two (6), so as to ensure that the component one (16) and the component two (6) move toward each other along the gear (3) under the action of an external force and squeeze the compression spring (5) between the two. The component one (16) and the component two (6) are both provided with an ultrasonic rangefinder (13) at the connection point with the two ends of the compression spring (5), which can detect the relative distance between the component one (16) and the component two (6) in real time, and read the pressure data of the compression spring (5) in real time through the integrated data reader (14); The high-strength gear nut (2) is in contact with the component one (16). When a prestressed moment is applied to the high-strength gear nut (2), the high-strength gear nut (2) generates an extrusion force on the component one (16). The component one (16) is displaced toward the component two (6) through the gear (3) and driven by the transmission toothed belt (4). During the displacement process, the compression spring (5) between the compression component one (16) and the component two (6) generates an internal force. At this time, the internal force of the compression spring (5) is balanced with the applied prestress and the values ​​are equal. The purpose of measuring the prestress is achieved by reading the state of the compression spring (5). In order to prevent the tray (7) from squeezing the monitor under the push of the rock mass when the surrounding rock undergoes external normal deformation, causing the prestress monitoring value to rise suddenly and cause a serious engineering accident, a tray nut stabilizer (15) is set between the tray (7) and the high-strength gear nut (2) to maintain the prestressing effect between the tray (7) and the high-strength gear nut (2). The tray nut stabilizer (15) includes a telescopic rod (18) with an adjustable middle length, and a length fixing knob (19) for adjusting the length of the telescopic rod (18) is provided in the middle. The non-retractable end (20) on one side of the telescopic rod (18) is connected to the high-strength gear nut (2) through a high-strength bolt (17); the non-retractable end (20) on the other side is connected to the tray (7) through a high-strength bolt (17); the tray nut stabilizer (15) is installed after the prestressing is completed, which can prevent the prestressing failure caused by the external normal deformation of the rock mass (8) and at the same time ensure the measurement accuracy of the prestressing.

2. The device for monitoring anchor rod prestressing using an ultrasonic spring according to claim 1, characterized in that: The tail of the anchor rod (9) is provided with a high-density thread section (1), and the high-strength gear nut (2) is rotatably fixed to the tail of the anchor rod (9) through the high-density thread section (1).

3. The device for monitoring anchor rod prestressing using an ultrasonic spring according to claim 2, characterized in that: In the ultrasonic spring prestressing monitor, the prestressing force transmitted from the high-strength gear nut (2) to the component (16) is The compression amount of the compression spring (5) There is a positive correlation , where the compression The size is measured by the ultrasonic rangefinder (13) placed between the compression springs (5). The built-in data line (12) transmits the signal to the integrated data reader (14). After the corresponding formula is calculated, it is converted into a prestress value and displayed on the screen. The specific prestress value and spring compression The corresponding relationship between ,in is the elastic constant of the compression spring (5), is the diameter of the high-strength gear nut (2), and d is the diameter of the anchor rod (9).

4. The device for monitoring anchor rod prestressing using an ultrasonic spring according to claim 3, characterized in that: The ultrasonic spring prestress monitoring device includes a gear (3), a component 1 (16), a component 2 (6), a compression spring (5), an ultrasonic rangefinder (13) and an integrated data reader (14), all of which are arranged in a housing. The prestress value of the integrated data reader (14) is displayed on a screen arranged on the housing, and the prestress value data changes in real time according to the condition of the compression spring (5).

5. A method for using the device for monitoring anchor rod prestress using ultrasonic springs according to claim 4, characterized in that Here are the steps: Step 1: Arrange anchor holes (10) at target locations on the rock mass (8); Step 2: Place the anchor rod (9) into the anchor hole (10), place the tray (7) to press the outer rock wall of the anchor hole (10) to play its role; put the ultrasonic spring prestressing monitor on the anchor rod (9), and manually return the component two (6) to the bottom of the polymer material shell (11). At this time, the component one (16) is also driven by the gear (3) and the respective transmission belts (4) to move freely to the initial position; Step 3: Put the high-strength gear nut (2) onto the high-density thread section (1) of the anchor rod (9), apply prestressing torque to the high-strength gear nut (2) by the corresponding machine, and screw it in clockwise toward the rock mass (8) until the high-strength gear nut (2) lightly contacts the component 1 (16) of the ultrasonic spring prestressing monitor, and then stop applying the prestressing torque; Step 4: Turn on the ultrasonic rangefinder (13) to initialize the data. The ultrasonic rangefinder (13) will check the distance between the compression spring (5) of the first component (16) and the second component (6) at a preset frequency. Under the condition of the ultrasonic wave velocity, the integrated data reader (14) calculates the initial distance between the two ends of the compression spring (5) when it is not prestressed. , and record the position, then continue to use the corresponding machinery to apply prestressing torque to the high-strength gear nut (2), so that it continues to rotate toward the rock mass (8), at this time, the built-in data line (12) connected to the ultrasonic rangefinder (13) continuously transmits data to the integrated data reader (14) according to the frequency, and displays the current prestressing value in real time; Step 5: Watch the prestress value displayed on the integrated data reader (14). When the value reaches the engineering requirement, stop applying the prestress torque and then record the final position. , and according to the formula: and Calculate the final prestressing value; Step 6. After the prestress is no longer required to be measured, the pallet nut stabilizer (15) is installed between the high-strength gear nut (2) and the pallet (7), the length fixing knob (19) is loosened, the telescopic rod (18) is adjusted to a suitable position, and the length fixing knob (19) is re-tightened. Two high-strength bolts (17) are installed, the first one fixing the high-strength gear nut (2) and the telescopic rod (18) together, and the second one fixing the pallet (7) and the non-telescopic end (20) together; at this time, the length of the telescopic rod (18) on the pallet nut stabilizer (15) has been fixed, and the entire pallet nut stabilizer (15) becomes a rigid top column, which is stuck between the high-strength gear nut (2) and the pallet (7), fixing the relative position of the two, and ensuring that the effect of applying the prestress will not fail due to the deformation of the rock mass (8); Step 7: Maintain the overall state until the project is completed, set the display screen of the integrated data reader (14) to the automatic screen-off mode to reduce unnecessary waste of electricity; when it is necessary to understand the prestressed state again, just turn on the digital display on the integrated data reader (14).

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