Self-adaptive optical fiber sensor system suitable for monitoring plateau permafrost region bridge

Abstract

The invention discloses a self-adaptive optical fiber sensor system suitable for plateau permafrost region bridge monitoring, which relates to the technical field of bridge engineering and specifically comprises a distributed optical fiber sensor network module, an optical fiber data transmission module, an edge calculation module, a power supply module, a protective shell module and a cloud monitoring platform. According to the invention, distributed and high-precision monitoring of bridge strain, vibration, temperature and displacement is realized through the distributed optical fiber sensor network module, the response speed and efficiency of the system are improved through the edge calculation module, and the edge calculation module solves the interference problem of temperature fluctuation on measurement data through the adaptive temperature compensation unit. Therefore, the cloud monitoring platform can carry out data visualization and graded early warning. Long-term safe operation monitoring of the frozen soil region bridge can be realized, and the frozen soil region bridge maintenance management level is improved.

Description

Technical Field

[0001] This invention relates to the field of bridge engineering technology, and more specifically to an adaptive fiber optic sensor system suitable for bridge monitoring in high-altitude permafrost regions. Background Technology

[0002] China is the world's third largest country in terms of permafrost, with a total permafrost area of ​​1.65 × 10⁻⁶. 6 Permafrost covers approximately 17% of China's total land area, with its distribution concentrated in high-altitude, high-latitude regions in the western and northeastern parts of the country, including the Qinghai-Tibet Plateau and the Greater and Lesser Khingan Mountains. Bridges, due to their minimal thermal disturbance to permafrost, have become a crucial structural element traversing permafrost regions; for example, 5.7% of the bridges on the Qinghai-Tibet Railway are located in permafrost areas, totaling 125 kilometers in length. However, the unique geological and climatic environment of permafrost regions presents bridges with structural safety challenges far exceeding those in ordinary areas, making their maintenance and monitoring needs more urgent and complex.

[0003] The structural damage risk of bridges in high-altitude permafrost regions stems from the triple coupling effect of "soil freeze-thaw cycle - environmental action - load effect". On the one hand, permafrost has significant "freeze-thaw settlement" characteristics - the volume expansion of frozen soil in winter leads to the lifting of bridge foundations, while the thawing of permafrost in summer causes foundation settlement. This periodic deformation causes continuous stress alternation in beams and piers, accelerating defects such as support displacement and beam cracking. On the other hand, permafrost regions generally have harsh environments such as low temperatures, strong radiation, heavy snow, and drastic diurnal temperature differences. These not only exacerbate concrete surface weathering and steel corrosion, but also cause existing cracks to continue to expand due to the "water freezing and ice expansion" effect. Coupled with the long-term effects of alternating vehicle loads, key bridge components are prone to forming a vicious cycle of "initial cracks - rapid expansion - structural stiffness reduction". In severe cases, this may lead to safety accidents such as support failure and beam fracture, posing a significant threat to the traffic safety of linear engineering projects.

[0004] The core of bridge structural health monitoring is the accurate capture and dynamic tracking of damage, but the special environment of the plateau permafrost region exposes significant limitations in existing monitoring technologies: 1. Insufficient adaptability of traditional manual inspection and simple tools: The monitoring areas in the plateau permafrost region are mostly high-altitude and remote areas. Low temperatures, strong winds, blizzards and other severe weather not only significantly increase the safety risks of manual inspection, but also make the accuracy of visual inspection more significantly affected by light and visibility. At the same time, manual single-point measurement cannot cover the full-area monitoring of the long-span structure of the bridge, making it difficult to capture distributed cracks or displacements caused by frost heave and thaw settlement, and it is impossible to achieve real-time data feedback, making it difficult to give timely warnings of sudden diseases.

[0005] 2. Conventional non-destructive testing technologies have poor environmental adaptability: Although technologies such as ultrasonic flaw detection and laser scanning can improve the accuracy of local measurements, the equipment is large and the installation is complicated. In the low-temperature environment of plateau permafrost areas, problems such as probe icing and unstable signal transmission are prone to occur. Moreover, these technologies are sensitive to vibration and electromagnetic interference. The continuous structural vibration caused by vehicle traffic can easily lead to distortion of the detection signal and make it impossible to accurately identify subtle changes in cracks.

[0006] 3. Performance limitations of traditional sensors become apparent: Currently widely used electrical sensors are prone to performance drift in the low-temperature environment of plateau permafrost regions, and have weak resistance to corrosion and electromagnetic interference. They are also prone to aging and failure when exposed to the dry and wet, freeze-thaw environments of permafrost regions for a long time. More importantly, traditional sensors are mostly single-point, single-parameter monitoring devices, and cannot simultaneously collect multi-dimensional data such as permafrost temperature, bridge displacement, and structural stress. The occurrence of bridge defects in permafrost regions is the result of the coupling of multiple factors such as "freeze-thaw-load-environment". Without multi-dimensional data support, it is difficult to accurately analyze the crack development mechanism and make it impossible to predict defects in advance.

[0007] Adaptive fiber optic sensor systems, with their resistance to high and low temperatures, electromagnetic interference, and corrosion, can adapt to the extreme environments of plateau permafrost regions. Furthermore, their "adaptive" nature allows them to automatically adjust sampling frequency, sensitivity, and other parameters according to environmental changes, ensuring stable monitoring accuracy. They can also achieve distributed, multi-parameter synchronous monitoring, providing data support for analyzing the correlation mechanism between permafrost heave and thawing settlement and bridge structural damage. Therefore, developing adaptive fiber optic sensor systems suitable for bridge monitoring in plateau permafrost regions is a key requirement for improving bridge maintenance and management in these areas. Summary of the Invention

[0008] To improve the maintenance and management of bridges in permafrost regions and ensure the long-term safe operation of these projects, this invention provides an adaptive fiber optic sensor system suitable for bridge monitoring in plateau permafrost areas. Specifically, it includes the following technical solutions: An adaptive fiber optic sensor system suitable for bridge monitoring in plateau permafrost regions includes: a distributed fiber optic sensor network module, a fiber optic data transmission module, an edge computing module, a power supply module, a protective housing module, and a cloud monitoring platform; The distributed optical fiber sensor network module establishes a data connection with the edge computing module through the optical fiber data transmission module, the edge computing module establishes a data connection with the cloud monitoring platform, and the edge computing module establishes an electrical connection with the power module. The edge computing module and the power module are housed inside the protective housing module. The distributed optical fiber sensor network module includes multiple fiber Bragg grating array units; the edge computing module includes a data receiving unit, a data filtering unit, a data storage unit, an adaptive temperature compensation unit, and a data uploading unit; the power supply module includes a solar panel and an energy storage battery; and the cloud monitoring platform includes a data visualization unit and a hierarchical early warning unit.

[0009] Preferably, the fiber Bragg grating array unit is arranged in a grid pattern, includes a series of fiber grating points, and integrates temperature-sensitive elements for synchronously acquiring strain, temperature, vibration, and displacement data, wherein the vibration data is derived through optical wavelength frequency shift.

[0010] Preferably, the fiber Bragg grating array unit is installed by epoxy resin bonding and drilling, so that the fiber grating dots of the fiber Bragg grating array unit are closely fitted to the bridge structure being tested.

[0011] Preferably, the data receiving unit is used to receive data transmitted by the fiber optic data transmission module, the data filtering unit is used to filter the original data, the data storage unit is used to store the filtered valid data, the adaptive temperature compensation unit is used to perform temperature compensation on the filtered original strain data, and the data uploading unit is used to compress and upload the filtered valid data and the temperature-compensated data, and establish wireless communication with the cloud monitoring platform.

[0012] Preferably, the data storage unit includes a historical database and a parameter database. The historical database is used to store filtered valid data and temperature-compensated data, while the parameter database is used to store algorithm parameter data.

[0013] Preferably, the solar panel is used to convert solar energy into electrical energy, and the energy storage battery is used to store electrical energy to power the distributed fiber optic sensor network module and the edge computing module.

[0014] Preferably, the data visualization unit is used to visualize the data uploaded by the edge computing module, and the hierarchical early warning unit is used to conduct hierarchical early warning based on data evaluation.

[0015] Compared with existing technologies, the adaptive fiber optic sensor system for bridge monitoring in plateau permafrost regions disclosed in this invention has the following advantages: 1. The solar panel of the power module of the present invention absorbs solar energy and converts it into electrical energy during the day. Part of the energy is used to directly power the distributed optical fiber sensor network module and the edge computing module, and the other part is stored in the energy storage battery to ensure the continuous operation of the system at night and on cloudy days. 2. The protective shell module of the present invention uses highly corrosion-resistant composite materials, such as glass fiber reinforced plastic, to provide dustproof, waterproof and low-temperature protection for the internal edge computing module and power module; 3. The fiber Bragg grating array unit of the distributed fiber optic sensor network module of the present invention collects raw strain, temperature, vibration and displacement data. These raw data are transmitted losslessly to the data receiving unit of the edge computing module through the fiber optic data transmission module, thereby realizing the lossless transmission of raw data. 4. The adaptive temperature compensation unit of the present invention retrieves filtered strain and temperature data from the historical database, retrieves algorithm parameters from the parameter database, performs temperature compensation on the strain data, and stores the temperature-compensated strain data back into the historical database. At the same time, the temperature compensation coefficient is iteratively updated based on the historical temperature compensation data at a set time and stored in the parameter database. This can achieve accurate correction of the original data, fully consider environmental factors such as temperature, ensure the accuracy of the output data, and improve data reliability. 5. The data visualization unit of the cloud monitoring platform of the present invention visualizes the received data in the form of charts, and the graded early warning unit evaluates the early warning threshold range in which the data is located, and then performs graded early warning. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the system structure of the present invention; Figure 2 This is a schematic diagram of the protective shell module of the present invention; Detailed Implementation

[0017] The technical solutions of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described technical solutions are only a part of the present invention, and not all of the technical solutions and measures. All other technical solutions obtained by those skilled in the art based on the implementation of the technical solutions of the present invention without creative effort are within the scope of protection of the present invention.

[0018] like Figure 1-2 As shown, the present invention discloses an adaptive fiber optic sensor system suitable for bridge monitoring in plateau permafrost regions, specifically including a distributed fiber optic sensor network module 1, a fiber optic data transmission module 2, an edge computing module 3, a power supply module 4, a protective housing module 5, and a cloud monitoring platform 6. The distributed optical fiber sensor network module 1 establishes a data connection with the edge computing module 3 through the optical fiber data transmission module 2, the edge computing module 3 establishes a data connection with the cloud monitoring platform 6, and the edge computing module 3 establishes an electrical connection with the power module 4. The edge computing module 3 and the power module 4 are housed inside the protective housing module 5.

[0019] Furthermore, the distributed optical fiber sensor network module 1 is used for data acquisition, the optical fiber data transmission module 2 is used for data transmission, the edge computing module 3 is used for edge computing, the power supply module 4 is used to power the distributed optical fiber sensor network module 1 and the edge computing module 3, the protective housing module 5 is used to protect the edge computing module 3 and the power supply module 4, and the cloud monitoring platform 6 is used for remote monitoring.

[0020] Furthermore, the distributed optical fiber sensor network module 1 includes multiple fiber Bragg grating array units 7, which are arranged in a grid pattern, contain a series of fiber grating points, and integrate temperature-sensitive elements for synchronously acquiring strain, temperature, vibration, and displacement data, wherein the vibration data is derived through optical wavelength frequency shift. The edge computing module 3 includes a data receiving unit 8, a data filtering unit 9, a data storage unit 10, an adaptive temperature compensation unit 11, and a data uploading unit 12; Furthermore, the data receiving unit 8 is used to receive data transmitted by the fiber optic data transmission module 2, the data filtering unit 9 is used to filter the original data, the data storage unit 10 is used to store the filtered valid data, the adaptive temperature compensation unit 11 is used to perform temperature compensation on the filtered original strain data, and the data uploading unit 12 is used to compress and upload the filtered valid data and the temperature-compensated data.

[0021] Furthermore, the power module 4 includes a solar panel 13 and an energy storage battery 14. The solar panel 13 provides electrical energy, and the energy storage battery 14 stores electrical energy and supplies power to the system.

[0022] Furthermore, the cloud monitoring platform 6 includes a data visualization unit 15 and a hierarchical early warning unit 16, which respectively provide data visualization and hierarchical early warning.

[0023] The working steps of the adaptive fiber optic sensor system for bridge monitoring in high-altitude permafrost regions provided by this invention are as follows: Step 1: First, multiple fiber Bragg grating array units 7 are arranged in a grid pattern in the bridge structure to be inspected, specifically including the mid-span of the main beam, the bottom of the pier, and the interface between the foundation and the permafrost layer, to complete the deployment of the distributed fiber optic sensor network module 1; The fiber Bragg grating array units 7 are installed by epoxy resin bonding and drilling, so that the fiber grating points of the fiber Bragg grating array units 7 are closely attached to the bridge structure to be inspected.

[0024] Step 2: Place the edge computing module 3 and the energy storage battery 14 together inside the protective housing module 5, and then install the solar panel 13 on the top of the bridge railing in a well-lit area, and connect it with the energy storage battery 14 to form a power supply circuit. Step 3: Enter the initial algorithm parameters into the parameter database 18 of the data storage unit 10, establish communication between the data receiving unit 8 and the optical fiber data transmission module 2, and establish communication between the data uploading unit 12 and the cloud monitoring platform 6. Step 4: Use the distributed optical fiber sensor network module 1 to collect the original strain, temperature, vibration and displacement data of the bridge structure, and transmit them to the edge computing module 3 in real time through the optical fiber data transmission module 2. Step 5: The data filtering unit 9 filters the collected raw data and stores the filtered valid data in the data storage unit 10. Step 6: The adaptive temperature compensation unit 11 performs temperature compensation on the filtered effective data and stores the temperature-compensated data in the data storage unit 10. Based on historical temperature compensation data, the adaptive temperature compensation unit 11 uses the least squares method to iteratively optimize the temperature compensation coefficient at a set time and stores the updated temperature compensation coefficient in the data storage unit 10. Step 7: The data upload unit 12 compresses the filtered valid data and the temperature-compensated data and uploads them to the cloud monitoring platform 6. After receiving the data, the cloud monitoring platform 6 visualizes the data and provides graded early warnings based on the data evaluation. The tiered early warning system includes no warning, yellow warning, and red warning. When there is no warning, only data is recorded and no warning is triggered. When a yellow warning is triggered, a pop-up window is displayed on the cloud monitoring platform 6, marking the risk location. When a red warning is triggered, the audible and visual alarm device on the protective shell module 5 is activated, the terminal pushes the warning information, a pop-up window is displayed on the cloud monitoring platform 6, and a preset emergency response plan is called and pushed to the local emergency department.

[0025] Compared with existing technologies, the adaptive fiber optic sensor system for bridge monitoring in plateau permafrost regions disclosed in this invention has the following advantages: 1. The solar panel of the power module of the present invention absorbs solar energy and converts it into electrical energy during the day. Part of the energy is used to directly power the distributed optical fiber sensor network module and the edge computing module, and the other part is stored in the energy storage battery to ensure the continuous operation of the system at night and on cloudy days. 2. The protective shell module of the present invention uses highly corrosion-resistant composite materials, such as glass fiber reinforced plastic, to provide dustproof, waterproof and low-temperature protection for the internal edge computing module and power module; 3. The fiber Bragg grating array unit of the distributed fiber optic sensor network module of the present invention collects raw strain, temperature, vibration and displacement data. These raw data are transmitted losslessly to the data receiving unit of the edge computing module through the fiber optic data transmission module, thereby realizing the lossless transmission of raw data. 4. The adaptive temperature compensation unit of the present invention retrieves filtered strain and temperature data from the historical database, retrieves algorithm parameters from the parameter database, performs temperature compensation on the strain data, and stores the temperature-compensated strain data back into the historical database. At the same time, the temperature compensation coefficient is iteratively updated based on the historical temperature compensation data at a set time and stored in the parameter database. This can achieve accurate correction of the original data, fully consider environmental factors such as temperature, ensure the accuracy of the output data, and improve data reliability. 5. The data visualization unit of the cloud monitoring platform of the present invention visualizes the received data in the form of charts, and the graded early warning unit evaluates the early warning threshold range in which the data is located, and then performs graded early warning.

[0026] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. An adaptive fiber optic sensor system suitable for bridge monitoring in high-altitude permafrost regions, characterized in that, include: Distributed fiber optic sensor network module (1), fiber optic data transmission module (2), edge computing module (3), power supply module (4), protective housing module (5), and cloud monitoring platform (6). The distributed optical fiber sensor network module (1) establishes a data connection with the edge computing module (3) through the optical fiber data transmission module (2), the edge computing module (3) establishes a data connection with the cloud monitoring platform (6), the edge computing module (3) establishes an electrical connection with the power module (4), and the edge computing module (3) and the power module (4) are set inside the protective shell module (5); The distributed optical fiber sensor network module (1) includes multiple fiber Bragg grating array units (7); the edge computing module 3 includes a data receiving unit (8), a data filtering unit (9), a data storage unit (10), an adaptive temperature compensation unit (11), and a data uploading unit (12); the power module (4) includes a solar panel (13) and an energy storage battery (14); the cloud monitoring platform (6) includes a data visualization unit (15) and a hierarchical early warning unit (16).

2. The adaptive fiber optic sensor system for bridge monitoring in plateau permafrost regions according to claim 1, characterized in that, The fiber Bragg grating array unit (7) is arranged in a grid pattern, contains a series of fiber grating points, and integrates temperature-sensitive elements for synchronously acquiring strain, temperature, vibration and displacement data, wherein the vibration data is derived by optical wavelength frequency shift.

3. The adaptive fiber optic sensor system for bridge monitoring in plateau permafrost regions according to claim 1 or 2, characterized in that, The fiber Bragg grating array unit (7) is installed by epoxy resin bonding and drilling, so that the fiber grating points of the fiber Bragg grating array unit (7) are closely fitted with the bridge structure being tested.

4. The adaptive fiber optic sensor system for bridge monitoring in plateau permafrost regions according to claim 1, characterized in that, The data receiving unit (8) is used to receive data transmitted by the fiber optic data transmission module (2), the data filtering unit (9) is used to filter the original data, the data storage unit (10) is used to store the filtered effective data, the adaptive temperature compensation unit (11) is used to perform temperature compensation on the filtered original strain data, and the data uploading unit (12) is used to compress and upload the filtered effective data and the temperature-compensated data, and establish wireless communication with the cloud monitoring platform (6).

5. The adaptive fiber optic sensor system for bridge monitoring in high-altitude permafrost regions according to claim 1, characterized in that, The data storage unit (10) includes a historical database (17) and a parameter database (18). The historical database (17) is used to store the filtered valid data and the temperature-compensated data, and the parameter database (18) is used to store the algorithm parameter data.

6. The adaptive fiber optic sensor system for bridge monitoring in plateau permafrost regions according to claim 1, characterized in that, The solar panel (13) is used to convert solar energy into electrical energy, and the energy storage battery (14) is used to store electrical energy to power the distributed optical fiber sensor network module (1) and the edge computing module (3).

7. The adaptive fiber optic sensor system for bridge monitoring in plateau permafrost regions according to claim 1, characterized in that, The data visualization unit (15) is used to visualize the data uploaded by the edge computing module (3), and the hierarchical early warning unit (16) is used to evaluate the data and issue hierarchical early warnings.

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