Highway tunnel construction disaster monitoring device

Abstract

The utility model relates to the technical field of tunnel construction safety monitoring, and discloses a highway tunnel construction disaster monitoring device which comprises a protective shell, a main body frame is fixedly connected in the protective shell, and an early warning and display module is arranged on the front side wall of the main body frame. The early warning and display module comprises an LCD touch screen and an audible and visual alarm. The audible and visual alarm comprises a high-brightness LED lamp and a high-decibel buzzer. According to the highway tunnel construction disaster monitoring device, the protective shell, the main body frame, the protective cover, the limiting lifting frame, the servo motor, the two-way screw rod, the limiting lifting block, the mounting clamping block, the high-strength mounting bracket, the magnetic suction strip, the mounting butt joint frame and the stable base are arranged in a matched manner; the effect of stably installing the disaster monitoring instrument in the highway tunnel construction process is achieved, and meanwhile personnel can conveniently disassemble and overhaul the disaster monitoring instrument.

Description

Technical Field

[0001] This utility model relates to the field of tunnel construction safety monitoring technology, specifically a highway tunnel construction disaster monitoring device. Background Technology

[0002] During highway tunnel construction, geological disasters (such as collapses, rock bursts, and water inrushes) and construction environment problems (such as toxic gases, dust, and abnormal temperature and humidity) are the main safety hazards.

[0003] Traditional monitoring methods typically rely on manual inspections and single sensors. However, manual inspections cannot achieve continuous 24-hour monitoring and are difficult to detect sudden disasters in a timely manner. The monitoring range of a single sensor is limited and cannot fully reflect the tunnel construction environment. Existing monitoring equipment has limited functions and cannot achieve multi-parameter comprehensive analysis and early warning. Therefore, this utility model provides a highway tunnel construction disaster monitoring device. Utility Model Content

[0004] (a) Technical problems to be solved

[0005] To address the shortcomings of existing technologies, this utility model provides a highway tunnel construction disaster monitoring device, which solves the problems mentioned in the background art.

[0006] (II) Technical Solution

[0007] To achieve the above objectives, this utility model provides the following technical solution: a highway tunnel construction disaster monitoring device, comprising a protective shell, a main frame fixedly connected inside the protective shell, an early warning and display module provided on the front side wall of the main frame, the early warning and display module including an LCD touch screen and an audible and visual alarm, the audible and visual alarm including a high-brightness LED light and a high-decibel buzzer, a filter cooling fan provided on the rear side inside the main frame, a data acquisition and transmission module, a data processing and analysis module, and a power supply module provided below the filter cooling fan inside the main frame, the data acquisition and transmission module including a data acquisition unit and a data transmission unit, the data processing and analysis module including an edge computing unit and a cloud computing platform transmission module, the power supply module including a solar panel and a lithium battery pack, and a protective shielding device movably connected to the right side wall of the protective shell via a hinge. The protective shell has a limit lifting frame fixedly connected to its left side wall. A servo motor is fixedly connected inside the limit lifting frame, and a bidirectional screw is fixedly connected to the output end of the servo motor. Limit lifting blocks are threaded into the two opposing threaded grooves on the surface of the bidirectional screw. A mounting block is fixedly connected to the surface of the limit lifting block, and a high-strength mounting bracket is engaged with the surface of the mounting block. A magnetic strip is fixedly connected to the outer side wall of the high-strength mounting bracket. A multi-parameter sensor module is installed on the exterior of the protective shell. This module includes geological parameter sensors and environmental parameter sensors. The geological parameter sensors include displacement sensors, stress sensors, and vibration sensors. The environmental parameter sensors include temperature and humidity sensors, gas sensors, and dust sensors. A mounting docking frame is fixedly connected to the inner side wall of the high-strength mounting bracket, and a stable base is fixedly connected to the bottom of the protective shell.

[0008] Preferably, the protective shell is made of high-strength aluminum alloy, the protective shell is rectangular in shape, the surface of the protective shell has an anti-slip texture design, the protective shell has an IP7 protection rating, the protective shell is engineering yellow in color, and the main frame is made of stainless steel.

[0009] Preferably, the LCD touch screen is located at the center of the front side wall of the main frame, and the high-brightness LED and the high-decibel buzzer are respectively located on the left and right sides of the LCD touch screen.

[0010] Preferably, the data acquisition unit uses a high-precision ADC chip to convert the analog signal output by the sensor into a digital signal, and the data transmission unit transmits the data to the data processing center in real time through a LoRa or G module.

[0011] Preferably, the edge computing unit uses an integrated edge computing chip to perform preliminary data processing and analysis, and the cloud computing platform transmission module uses a G module to transmit data to the cloud and then uses machine learning algorithms for in-depth analysis and disaster risk identification.

[0012] Preferably, the displacement sensor, stress sensor, and vibration sensor are all fixedly connected to a high-strength mounting bracket. The displacement sensor, which is a laser displacement sensor or a fiber optic grating sensor, is connected to the data acquisition unit via a waterproof connector. The stress sensor, which is a resistance strain gauge or a piezoelectric sensor, is connected to the data acquisition unit via a waterproof connector. The vibration sensor, which is a triaxial accelerometer, is connected to the data acquisition unit via a waterproof connector. The temperature and humidity sensor, gas sensor, and dust sensor are all fixedly connected to a protective housing. The temperature and humidity sensor, which is a digital temperature and humidity sensor, is connected to the data acquisition module via a waterproof connector. The gas sensor, which is an electrochemical gas sensor, is connected to the data acquisition unit via a waterproof connector. The dust sensor, which is a laser scattering dust sensor, is connected to the data acquisition unit via a waterproof connector.

[0013] Preferably, the solar panel is installed at the tunnel entrance and electrically connected to the inverter and lithium battery pack via a power cord. The surface of the protective cover is provided with an observation window. The external fixed connection of the mounting block is a wear-resistant sleeve. The surface of the high-strength mounting bracket is threaded with high-strength fixing bolts.

[0014] (III) Beneficial Effects

[0015] Compared with the prior art, this utility model provides a highway tunnel construction disaster monitoring device, which has the following beneficial effects:

[0016] This highway tunnel construction disaster monitoring device, through the coordinated arrangement of a protective shell, main frame, protective cover, limit lifting frame, servo motor, bidirectional screw, limit lifting block, mounting clip, high-strength mounting bracket, magnetic strip, mounting docking frame, and stable base, allows for easy installation. During use, the high-strength mounting bracket is fixed to the appropriate height on the highway tunnel wall surface using high-strength bolts. The controller then activates the servo motor, driving the bidirectional screw to rotate left and right. This, in turn, causes the limit lifting block to move in opposite directions along the threaded limit of the bidirectional screw until it engages with the high-strength mounting bracket for tight installation. Magnetic strips can be used for enhanced positioning and fixation on metal surfaces. For disassembly and maintenance, the device can be disassembled and placed stably on the stable base. This provides stable installation for the disaster monitoring instrument during highway tunnel construction and facilitates disassembly and maintenance. The device also features an LCD touchscreen, high-brightness LED lights, a high-decibel buzzer, a filter cooling fan, a data acquisition unit, a data transmission unit, and an edge computing unit. The system is equipped with a combination of components including a cloud computing platform transmission module, solar panels, lithium battery packs, displacement sensors, stress sensors, vibration sensors, temperature and humidity sensors, gas sensors, and dust sensors. During operation, the displacement, stress, vibration, temperature, humidity, gas, and dust sensors are powered by an external power source to transmit multi-dimensional environmental data in real time to a data acquisition unit. This data is then collected by the data acquisition unit and transmitted to a warning display module via a data transmission unit. The system provides high-decibel alarms via an audible and visual alarm and displays the data in real time on an LCD touchscreen. After preliminary calculation and analysis by the edge computing unit, the data is further transmitted to the cloud via the cloud computing platform transmission module for in-depth analysis using machine learning algorithms. This system effectively monitors and analyzes geological hazards (such as landslides, rock bursts, and water inrushes) and environmental problems (such as toxic gases, dust, and abnormal temperature and humidity) during highway tunnel construction. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the first embodiment of the present invention;

[0018] Figure 2 This is a schematic diagram of the second embodiment of the present invention;

[0019] Figure 3 This is the first front sectional view of the present invention;

[0020] Figure 4 This is a schematic diagram of the power supply for disaster monitoring according to this utility model.

[0021] In the diagram: 1. Protective housing; 2. Main frame; 3. LCD touch screen; 4. High-brightness LED light; 5. High-decibel buzzer; 6. Filter cooling fan; 7. Data acquisition unit; 8. Data transmission unit; 9. Edge computing unit; 10. Cloud computing platform transmission module; 11. Solar panel; 12. Lithium battery pack; 13. Protective cover; 14. Limit lifting frame; 15. Servo motor; 16. Bidirectional screw; 17. Limit lifting block; 18. Mounting clip; 19. High-strength mounting bracket; 20. Magnetic strip; 21. Displacement sensor; 22. Stress sensor; 23. Vibration sensor; 24. Temperature and humidity sensor; 25. Gas sensor; 26. Dust sensor; 27. Mounting docking frame; 28. Stable base. Detailed Implementation

[0022] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0023] Please see Figure 1-4This utility model provides a technical solution: a highway tunnel construction disaster monitoring device, including a protective shell 1, and a combination of the protective shell 1, main frame 2, protective cover 13, limiting lifting frame 14, servo motor 15, bidirectional screw 16, limiting lifting block 17, mounting block 18, high-strength mounting bracket 19, magnetic strip 20, mounting docking frame 27, and stable base 28. In use, the high-strength mounting bracket 19 is fixed to a suitable height on the highway tunnel wall surface using high-strength fixing bolts. Then, the controller starts the servo motor 15, driving the bidirectional screw 16 to rotate left and right. The limiting lifting block 17 then drives the mounting block 18 to move in opposite directions, threadedly limiting the bidirectional screw 16 until it is locked into the high-strength mounting bracket 19. The instrument is securely installed and fixed. Magnetic strips 20 can be used for enhanced positioning on metal surfaces. When disassembly and maintenance are required, it can be disassembled and placed stably on the stabilizing base 28. This ensures stable installation of the disaster monitoring instrument during highway tunnel construction and facilitates disassembly and maintenance. The protective shell 1 is internally connected to the main frame 2. The front wall of the main frame 2 houses an early warning and display module, which includes an LCD touchscreen 3 and an audible and visual alarm. The system utilizes the LCD touchscreen 3, high-brightness LED lights 4, a high-decibel buzzer 5, a filter cooling fan 6, a data acquisition unit 7, a data transmission unit 8, an edge computing unit 9, a cloud computing platform transmission module 10, a solar panel 11, and a lithium battery. The system is configured with a pool group 12, displacement sensor 21, stress sensor 22, vibration sensor 23, temperature and humidity sensor 24, gas sensor 25, and dust sensor 26. During operation, the displacement sensor 21, stress sensor 22, vibration sensor 23, temperature and humidity sensor 24, gas sensor 25, and dust sensor 26 are connected to an external power supply to transmit multi-dimensional environmental data in real time to the data acquisition unit 7. The data is then collected by the data acquisition unit 7 and transmitted to the early warning display module via the data transmission unit 8. An alarm is triggered by a high-decibel buzzer 5 of the audible and visual alarm, and the data is displayed in real time on the LCD touchscreen 3. The edge computing unit 9 performs preliminary calculations and analysis, and further data is transmitted via cloud computing. The transmission module 10 transmits data to the cloud for in-depth analysis using machine learning algorithms. This enables real-time data monitoring and analysis of geological hazards such as landslides, rock bursts, and water inrushes, as well as environmental issues such as toxic gases, dust, and abnormal temperature and humidity during highway tunnel construction. The audible and visual alarm includes a high-brightness LED light 4 and a high-decibel buzzer 5. A filter cooling fan 6 is installed on the rear side of the main frame 2. Below the filter cooling fan 6 inside the main frame 2 are a data acquisition and transmission module, a data processing and analysis module, and a power supply module. The data acquisition and transmission module includes a data acquisition unit 7 and a data transmission unit 8. The data processing and analysis module includes an edge computing unit 9 and a cloud computing platform transmission module 10.The power supply module includes a solar panel 11 and a lithium battery pack 12. A protective cover 13 is hinged to the right side wall of the protective housing 1. A limit lifting frame 14 is fixedly connected to the left side wall of the protective housing 1. A servo motor 15 is fixedly connected inside the limit lifting frame 14. A bidirectional screw 16 is fixedly connected to the output end of the servo motor 15. Limit lifting blocks 17 are threaded into the two opposing threaded grooves on the surface of the bidirectional screw 16. A mounting block 18 is fixedly connected to the surface of the limit lifting block 17. A high-strength mounting bracket 19 is snapped onto the surface of the mounting block 18. A magnetic strip 20 is fixedly connected to the outer wall of the high-strength mounting bracket 19. A multi-parameter sensor module is installed on the outside of the protective housing 1. The multi-parameter sensor module is divided into geological parameter... The system includes sensors for geological parameters (displacement sensor 21, stress sensor 22, and vibration sensor 23), and sensors for environmental parameters (temperature and humidity sensor 24, gas sensor 25, and dust sensor 26). A mounting bracket 27 is fixedly connected to the inner wall of the high-strength mounting bracket 19. A stable base 28 is fixedly connected to the bottom of the protective housing 1. The protective housing 1 is made of high-strength aluminum alloy and has a cuboid shape. The surface of the protective housing 1 features an anti-slip texture design. The protective housing 1 has an IP67 protection rating and is painted engineering yellow. The main frame 2 is made of stainless steel. An LCD touchscreen 3 is located at the center of the front wall of the main frame 2. High-brightness LED lights 4 and high-resolution... The buzzers 5 are respectively located on the left and right sides of the LCD touch screen 3. The data acquisition unit 7 uses a high-precision ADC chip to convert the analog signals output by the sensors into digital signals. The data transmission unit 8 transmits the data to the data processing center in real time via LoRa or 5G modules. The edge computing unit 9 uses an integrated edge computing chip to perform preliminary processing and analysis of the data. The cloud computing platform transmission module 10 uses a 5G module to transmit the data to the cloud and then uses machine learning algorithms for in-depth analysis and disaster risk identification. The displacement sensor 21, stress sensor 22, and vibration sensor 23 are all fixedly connected to the high-strength mounting bracket 19. The displacement sensor 21 uses a laser displacement sensor or a fiber optic grating sensor and is connected to the data acquisition unit 7 through a waterproof connector. Stress sensor 22, employing a resistance strain gauge or piezoelectric sensor, is connected to data acquisition unit 7 via a waterproof connector. Vibration sensor 23, employing a triaxial accelerometer, is also connected to data acquisition unit 7 via a waterproof connector. Temperature and humidity sensor 24, gas sensor 25, and dust sensor 26 are all fixedly connected to protective housing 1. Temperature and humidity sensor 24 is a digital temperature and humidity sensor connected to the data acquisition module via a waterproof connector. Gas sensor 25 is an electrochemical gas sensor connected to data acquisition unit 7 via a waterproof connector. Dust sensor 26 is a laser scattering dust sensor connected to data acquisition unit 7 via a waterproof connector. Solar panel 11 is installed at the tunnel entrance and electrically connected to inverter and lithium battery pack 12 via power cord.The protective cover 13 has an observation window on its surface; the mounting block 18 is externally fixed with a wear-resistant sleeve; and the high-strength mounting bracket 19 has high-strength fixing bolts threaded onto its surface.

[0024] In summary, this highway tunnel construction disaster monitoring device, through the coordinated arrangement of a protective shell 1, a main frame 2, a protective cover 13, a limiting lifting frame 14, a servo motor 15, a bidirectional screw 16, a limiting lifting block 17, an installation clip 18, a high-strength installation bracket 19, a magnetic strip 20, an installation docking frame 27, and a stable base 28, allows for easy operation. During use, the high-strength installation bracket 19 is fixed to the highway tunnel wall at a suitable height using high-strength bolts. The controller then activates the servo motor 15, which drives the bidirectional screw 16 to rotate left and right, thereby causing the limiting lifting block 17 to move the installation clip 18. The locking block 18, with its threaded limit, moves in opposite directions on the surface of the bidirectional screw 16 until it is locked into the high-strength mounting bracket 19 for tight installation and fixation. On metal surfaces, it can be further secured using a magnetic strip 20. When disassembly and maintenance are required, it can be removed and placed stably on the stabilizing base 28. This provides stable installation for the disaster monitoring instrument during highway tunnel construction and facilitates disassembly and maintenance. The instrument is equipped with an LCD touchscreen 3, high-brightness LED lights 4, a high-decibel buzzer 5, a filter cooling fan 6, a data acquisition unit 7, and a data transmission unit 8. The system is configured with an edge computing unit 9, a cloud computing platform transmission module 10, a solar panel 11, a lithium battery pack 12, a displacement sensor 21, a stress sensor 22, a vibration sensor 23, a temperature and humidity sensor 24, a gas sensor 25, and a dust sensor 26. During operation, the displacement sensor 21, stress sensor 22, vibration sensor 23, temperature and humidity sensor 24, gas sensor 25, and dust sensor 26 are connected to an external power source to transmit multi-dimensional environmental data during highway tunnel construction to the data acquisition unit 7 in real time. The data acquisition unit 7 collects the data, which is then transmitted to the early warning display module via the data transmission unit 8. An alarm is triggered by a high-decibel buzzer 5 of the audible and visual alarm, and the data is displayed in real time on the LCD touchscreen 3. After preliminary calculation and analysis by the edge computing unit 9, the data is further transmitted to the cloud via the cloud computing platform transmission module 10 for in-depth analysis using machine learning algorithms. This system serves to monitor and analyze geological hazards (such as landslides, rock bursts, and water inrushes) and environmental problems (such as toxic gases, dust, and abnormal temperature and humidity) detected during highway tunnel construction in real time.

[0025] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installed," "equipped with," "sleeved / connected," "connected," etc., should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0026] In the description of this utility model, it should also be noted that the device structure and drawings of this utility model mainly describe the principle of this utility model. In terms of the technical aspects of this design principle, the setting of the power mechanism, power supply system and control system of the device is not fully described. However, under the premise that those skilled in the art understand the principle of the above utility model, the specific details of its power mechanism, power supply system and control system can be clearly understood. The control method in the application document is automatic control through a controller. The control circuit of the controller can be implemented by those skilled in the art through simple programming.

[0027] In the description of this utility model, it should also be noted that all standard parts used can be purchased from the market, and can be customized according to the description and drawings. The specific connection methods of each part adopt conventional methods such as bolts, rivets, and welding that are mature in the prior art. The machinery, parts and equipment adopt conventional models in the prior art, and the structure and principle of the components known to those skilled in the art can be learned by those skilled in the art through technical manuals or conventional experimental methods.

[0028] It should also be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0029] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A highway tunnel construction disaster monitoring device, comprising a protective shell (1), characterized in that: The protective shell (1) is fixedly connected to the main frame (2). The front side wall of the main frame (2) is provided with an early warning and display module. The early warning and display module includes an LCD touch screen (3) and an audible and visual alarm. The audible and visual alarm includes a high-brightness LED light (4) and a high-decibel buzzer (5). The rear side of the main frame (2) is provided with a filter cooling fan (6). Below the filter cooling fan (6) inside the main frame (2) are a data acquisition and transmission module, a data processing and analysis module, and a power supply module. The data acquisition and transmission module includes a data acquisition unit (7) and a data transmission unit (8). The data processing and analysis module includes an edge computing unit (9) and a cloud computing platform transmission module (10). The power supply module includes a solar panel (11) and a lithium battery pack (12). The right side wall of the protective shell (1) is movably connected to a protective cover (13) via a hinge. The left side wall of the protective shell (1) is fixedly connected to a limit lifting frame (14). The interior of the limit lifting frame (14) A servo motor (15) is fixedly connected, and a bidirectional screw (16) is fixedly connected to the output end of the servo motor (15). A limit lifting block (17) is threadedly connected to the two opposing threaded grooves on the surface of the bidirectional screw (16). A mounting block (18) is fixedly connected to the surface of the limit lifting block (17). A high-strength mounting bracket (19) is snapped onto the surface of the mounting block (18). A magnetic strip (20) is fixedly connected to the outer wall of the high-strength mounting bracket (19). A multi-parameter sensor module is provided on the outside of the protective shell (1). The multi-parameter sensor module is divided into a geological parameter sensor and an environmental parameter sensor. The geological parameter sensor includes a displacement sensor (21), a stress sensor (22), and a vibration sensor (23). The environmental parameter sensor includes a temperature and humidity sensor (24), a gas sensor (25), and a dust sensor (26). A mounting docking frame (27) is fixedly connected to the inner wall of the high-strength mounting bracket (19). A stable base (28) is fixedly connected to the bottom of the protective shell (1).

2. The highway tunnel construction disaster monitoring device according to claim 1, characterized in that: The protective shell (1) is made of high-strength aluminum alloy, the protective shell (1) is in the shape of a cuboid, the surface of the protective shell (1) is designed with anti-slip texture, the protective shell (1) has an IP67 protection rating, the protective shell (1) is in the color of engineering yellow, and the main frame (2) is made of stainless steel.

3. The highway tunnel construction disaster monitoring device according to claim 1, characterized in that: The LCD touch screen (3) is located at the center of the front side wall of the main frame (2), and the high-brightness LED light (4) and the high-decibel buzzer (5) are respectively set on the left and right sides of the LCD touch screen (3).

4. The highway tunnel construction disaster monitoring device according to claim 1, characterized in that: The data acquisition unit (7) uses a high-precision ADC chip to convert the analog signal output by the sensor into a digital signal, and the data transmission unit (8) transmits the data to the data processing center in real time through a LoRa or 5G module.

5. A highway tunnel construction disaster monitoring device according to claim 1, characterized in that: The edge computing unit (9) uses an integrated edge computing chip to perform preliminary processing and analysis of the data. The cloud computing platform transmission module (10) uses a 5G module to transmit the data to the cloud and then uses machine learning algorithms to perform in-depth analysis and identify disaster risks.

6. The highway tunnel construction disaster monitoring device according to claim 1, characterized in that: The displacement sensor (21), stress sensor (22), and vibration sensor (23) are all fixedly connected to the high-strength mounting bracket (19). The displacement sensor (21) is a laser displacement sensor or a fiber optic grating sensor connected to the data acquisition unit (7) through a waterproof connector. The stress sensor (22) is a resistance strain gauge or a piezoelectric sensor connected to the data acquisition unit (7) through a waterproof connector. The vibration sensor (23) is a triaxial accelerometer connected to the data acquisition unit (7) through a waterproof connector. The temperature and humidity sensor (24), gas sensor (25), and dust sensor (26) are all fixedly connected to the protective housing (1). The temperature and humidity sensor (24) is a digital temperature and humidity sensor connected to the data acquisition module through a waterproof connector. The gas sensor (25) is an electrochemical gas sensor connected to the data acquisition unit (7) through a waterproof connector. The dust sensor (26) is a laser scattering dust sensor connected to the data acquisition unit (7) through a waterproof connector.

7. A highway tunnel construction disaster monitoring device according to claim 1, characterized in that: The solar panel (11) is installed at the tunnel entrance and is electrically connected to the inverter and the lithium battery pack (12) via a power line. The protective cover (13) has an observation window on its surface. The mounting block (18) is externally fixed with a wear-resistant sleeve. The high-strength mounting bracket (19) is threaded with a high-strength fixing bolt.

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