Tunnel lining crack monitoring equipment and method

Abstract

The invention provides tunnel lining crack monitoring equipment and method, and the equipment is arranged between the building limit of a tunnel and the contour of the inner wall of a tunnel lining, and comprises a crack detection unit which is used for collecting the feature data of the tunnel lining crack, so as to monitor the crack of the tunnel lining; the supporting unit comprises a central rotating shaft; the supporting assemblies are rotatably arranged on the two sides of the central rotating shaft, each supporting assembly is formed by combining a plurality of supporting frames, the adjacent supporting frames located on the same side are in sliding connection and can be unfolded to be matched with the shape of a tunnel, the crack detection unit comprises a coarse detection unit, a medium detection unit and a fine detection unit, the size of the medium detection unit is not larger than 1 / 4 of that of the coarse detection unit, and the size of the fine detection unit is not larger than 1 / 4 of that of the medium detection unit. The size of the fine detection unit is not larger than 1 / 9 of that of the middle detection unit, and the coarse detection unit, the middle detection unit and the fine detection unit are arranged on the multiple supporting frames. The monitoring equipment disclosed by the invention has the comprehensive advantages of long term, continuity, wide area, universality, interference resistance, high reliability, easiness in maintenance, low cost and the like.

Description

Technical Field

[0001] This invention relates to the technical field of disaster prevention and control in underground engineering, specifically to a device and method for monitoring cracks in tunnel lining. Background Technology

[0002] In recent years, the number and total mileage of tunnels in China have shown a rapid growth trend. According to the "Statistical Bulletin on the Development of the Transportation Industry in 2024" released by the Ministry of Transport, as of the end of 2024, the total number of highway tunnels in China reached 28,724, with a total length of 32,596.6 kilometers, ranking first in the world in terms of tunnel construction scale. With the extension of service life, tunnel structures gradually develop defects, among which cracks are one of the main early manifestations of lining structure degradation, characterized by high frequency, strong destructiveness, and complex causes. The development of cracks can lead to lining spalling, reducing structural durability and impermeability; in severe cases, it may cause instability and collapse, seriously affecting the tunnel's load-bearing capacity and operational safety. Therefore, long-term monitoring of tunnel lining cracks has significant engineering implications. By obtaining time-series data on the changes in characteristic parameters such as crack length, location, and type, the timing and plan for intervention in the "observation-repair-reinforcement" process can be scientifically determined, avoiding excessive or delayed maintenance and reducing the total life-cycle cost. Simultaneously, it can provide early warning before crack penetration and load-bearing capacity degradation, improving the level of tunnel operational safety.

[0003] Currently, the following technical means are mainly used for monitoring cracks in tunnel lining: (1) Manual inspection: including visual inspection, crack width ruler, crack microscope and other methods. This type of method relies on the experience of the inspectors and is highly subjective; the detection efficiency is low and it is difficult to achieve high frequency or continuous monitoring; it requires road occupation or traffic closure for operation, which poses a high safety risk; at the same time, the data digitization level is low and it is difficult to incorporate into the information management system. (2) Contact displacement monitoring: including crack gauge, stress gauge, multi-point displacement gauge and other equipment. This type of method has limited monitoring points and low spatial coverage; installation and maintenance are complicated and labor costs are high; equipment and wiring costs are high and the monitoring area cannot be moved. (3) Fixed-point optical imaging detection: using high-definition industrial cameras and calibrated targets to image cracks. Its deployment cost is high, and it is greatly affected by environmental factors such as light, dust, and water mist, making it difficult to achieve large-scale automatic expansion and requiring high equipment maintenance. (4) Mobile optical imaging detection: automatic inspection is achieved through intelligent inspection robots. This method has high equipment costs, complex systems, and high requirements for operation and maintenance; it is greatly affected by tunnel traffic conditions, slope and obstacles, and the detection frequency is limited. (5) Other non-destructive testing methods: including infrared thermal imaging, acoustic emission, and ground-penetrating radar. These methods involve expensive equipment, complex operation, and require highly skilled personnel; the testing cycle is long, making them unsuitable for routine high-frequency monitoring; they are also susceptible to interference from electromagnetic noise and temperature differences, typically allowing only localized sampling inspections. In summary, existing tunnel crack monitoring technologies have limitations in terms of monitoring range, accuracy, automation level, and applicability. There is an urgent need for a crack monitoring device and method that can achieve long-term, continuous, wide-area, universal, interference-resistant, highly reliable, easy-to-maintain, and low-cost monitoring. Summary of the Invention

[0004] This invention is made to solve the above-mentioned problems, and its purpose is to provide a device and method for monitoring cracks in tunnel lining.

[0005] This invention provides a tunnel lining crack monitoring device, characterized by being positioned between the tunnel's structural clearance and the contour of the tunnel lining's inner wall. It includes: a crack detection unit for collecting characteristic data of tunnel lining cracks to monitor the cracks; and a support unit comprising: a central rotating shaft; and support components rotatably disposed on both sides of the central rotating shaft. The support components are formed by combining multiple support frames, with adjacent support frames on the same side slidably connected and capable of unfolding to match the shape of the tunnel. The crack detection unit includes a coarse detection unit, a medium detection unit, and a fine detection unit. The size of the medium detection unit is no greater than 1 / 4 of the coarse detection unit, and the size of the fine detection unit is no greater than 1 / 9 of the medium detection unit. The coarse, medium, and fine detection units are disposed on multiple support frames.

[0006] The tunnel lining crack monitoring device provided by the present invention may also have the following features: a mounting groove is provided on the tunnel lining, extending along the tunnel excavation direction, and a central rotating shaft is set in the mounting groove through a mounting hook and slidably connected to the mounting groove, which is used to drive the coarse detection unit, the intermediate detection unit and the fine detection unit to move along the tunnel axial direction to detect cracks.

[0007] The tunnel lining crack monitoring device provided by the present invention may also have the following feature: the support unit further includes a support spring, which is disposed on the support frame and corresponds to the position of the central rotating shaft, and is used to support the support frames on both sides.

[0008] The tunnel lining crack monitoring device provided by the present invention may also have the following feature: adjacent support frames located on the same side are slidably connected by unit rollers.

[0009] The tunnel lining crack monitoring device provided by the present invention may also have the following feature: prestressed springs are provided between adjacent support frames located on the same side.

[0010] The tunnel lining crack monitoring device provided by the present invention may also have the following features: wherein the coarse exploration unit includes: a large base plate; a large flow meter disposed on the large base plate; a large sealing ring disposed on the large base plate, matching the shape of the edge of the large base plate, and the large flow meter is located inside the large sealing ring.

[0011] The tunnel lining crack monitoring device provided by the present invention may also have the following features: wherein the central detection unit includes: a medium-sized base plate; multiple medium-sized flow meters disposed on the medium-sized base plate; a hygrometer disposed on the medium-sized base plate; and a medium-sized sealing ring disposed on the medium-sized base plate, matching the shape of the edge of the medium-sized base plate, with the hygrometer and multiple medium-sized flow meters located inside the medium-sized sealing ring.

[0012] The tunnel lining crack monitoring device provided by the present invention may also have the following features: wherein the fine detection unit includes: a micro base plate; multiple micro flow meters disposed on the micro base plate; a micro sealing ring disposed on the micro base plate, matching the shape of the edge of the micro base plate, and the multiple micro flow meters are located inside the micro sealing ring.

[0013] This invention also provides a method for monitoring tunnel lining cracks, based on a tunnel lining crack monitoring device, and includes the following steps: S1: Coarse detection step, using a coarse detection unit to monitor changes in airflow within the tunnel to determine the presence of cracks. When a local flow velocity anomaly is detected, the existence of cracks is automatically identified, the crack area is determined, and a medium detection unit and a fine detection unit are activated for detection; S2: Medium detection and traversal step, dividing the crack area into multiple zones, using a medium detection unit to further detect and locate the cracks within these zones, determining the distribution range of the cracks; S3: Fine detection and active tracking step, using a fine detection unit to gradually move within the crack distribution range of a zone, sequentially checking the development path of the cracks, determining the direction of the cracks, and repeating this step until the direction of the cracks in all zones is determined; S4: The crack image stitching and data aggregation steps summarize the crack directions in all zones, stitch them into a complete crack image, and transmit the crack parameters to the monitoring center; S5: Evaluation step, based on the crack image and crack parameters, evaluates the crack according to preset standards and determines whether intervention is needed, completing the preliminary monitoring process; S6: Continuous monitoring and periodic verification step, after the preliminary monitoring process is completed, the coarse detection unit is set to periodically return to the same crack area for re-examination. If the coarse detection unit detects airflow, but it is similar to the airflow recorded in S1, it is determined that the crack has not expanded further, and the original evaluation result is maintained; if the airflow shows a significant increase or change compared to the airflow recorded in S1, it is determined that the crack has expanded further or its characteristics have changed, and S1-S6 are repeated to monitor the crack.

[0014] The tunnel lining crack monitoring method provided by the present invention may also have the following features: wherein, in S4, the crack parameters include: airflow change rate, airflow velocity, crack type, crack location, and crack length.

[0015] The role and effect of invention

[0016] The tunnel lining crack monitoring equipment and method according to the present invention have the following beneficial effects:

[0017] The monitoring device of this invention has comprehensive advantages such as long-term, continuous, wide-area, universal, anti-interference, high reliability, easy maintenance, and low cost. Specifically:

[0018] The monitoring device of this invention is installed between the tunnel's structural clearance and the contour of the tunnel lining, without affecting traffic operation and capable of long-term stable operation. The monitoring device possesses excellent mobility, being slidably connected to a mounting slot carved into the tunnel lining and extending along the tunnel's excavation direction via a mounting hook, enabling wide-area coverage and dynamic inspection throughout the entire tunnel. The structural dimensions and shape of the monitoring device are flexibly adjustable to adapt to tunnel structures with different cross-sections and operating conditions. The monitoring device employs self-adaptive structures such as support springs and sealing rings, unaffected by environmental factors such as electromagnetic noise and temperature differences, ensuring stable and reliable signal acquisition. The components used are technologically mature, stable in performance, and not easily damaged. The monitoring device has a simple design principle, high modularity, and is easy to maintain, replace, and expand, with low manufacturing costs, enabling large-scale deployment and economical operation.

[0019] Furthermore, the tunnel lining crack monitoring method proposed in this invention achieves a graded monitoring mechanism from rapid screening to accurate identification through a gradient monitoring mode, namely, the coordinated work of three levels of crack detection units: coarse, medium, and fine. This can significantly shorten the monitoring cycle, reduce energy consumption and costs, and improve crack identification efficiency and monitoring intelligence. Attached Figure Description

[0020] Figure 1 This is a schematic diagram showing the location of the tunnel lining crack monitoring device in an embodiment of the present invention.

[0021] Figure 2 This is a schematic diagram of the tunnel lining crack monitoring device in an embodiment of the present invention.

[0022] Figure 3 This is a schematic diagram of the support unit in an embodiment of the present invention.

[0023] Figure 4 This is a schematic diagram of the usage state of the prestressed spring in an embodiment of the present invention.

[0024] Figure 5 This is a schematic diagram of the crack detection unit in an embodiment of the present invention.

[0025] Figure 6 This is a schematic diagram illustrating the combined working principle of the coarse probe unit and the intermediate probe unit in an embodiment of the present invention.

[0026] Figure 7 This is a schematic diagram illustrating the combined working principle of the intermediate probe unit and the fine probe unit in an embodiment of the present invention.

[0027] Figure 8 This is a schematic diagram illustrating the active tracking working principle of the fine-tuning unit in an embodiment of the present invention.

[0028] Figure 9 This is a schematic diagram of the detection range of the crack detection unit in an embodiment of the present invention.

[0029] Figure 10 This is a schematic diagram illustrating the safety assessment of tunnel lining cracks based on machine learning technology in an embodiment of the present invention.

[0030] Explanation of symbols for main components:

[0031] In the diagram: 100. Tunnel lining crack monitoring equipment; 1. Mounting slot; 2. Construction clearance; 3. Tunnel clearance section; 4. Outline; 5. Mounting hook; 6. Central rotating shaft; 7. Support spring; 8. Crack detection unit; 90. Support assembly; 9. Support frame; 10. Prestressed spring; 11. Unit roller; 12. Coarse detection unit; 13. Medium detection unit; 14. Fine detection unit; 15. Large flow meter; 151. Large base plate; 152. Large sealing ring; 16. Medium flow meter; 161. Medium base plate; 162. Medium sealing ring; 17. Miniature flow meter; 171. Miniature base plate; 172. Miniature sealing ring; 18. Hygrometer. Detailed Implementation

[0032] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0033] To make the technical means, creative features, objectives and effects of the present invention easy to understand, the following embodiments, in conjunction with the accompanying drawings, provide a detailed description of the tunnel lining crack monitoring device and method of the present invention.

[0034] Figure 1 This is a schematic diagram showing the location of the tunnel lining crack monitoring device in an embodiment of the present invention.

[0035] like Figure 1 As shown, a construction clearance 2 is provided within the tunnel cross-section, and the internal space of this clearance is the tunnel clearance cross-section 3. This area is the safe space range for trains or vehicles during operation. To avoid affecting the normal operation and traffic of the tunnel, the tunnel lining crack monitoring equipment (hereinafter referred to as the monitoring equipment) 100 should be located outside the construction clearance 2. This area is usually located between the tunnel construction clearance 2 and the outline 4 of the tunnel lining inner wall. This ensures the installation safety and structural stability of the monitoring equipment 100, and effectively avoids collisions and interference to the monitoring equipment 100 caused by vehicle operation and maintenance work, thereby ensuring the long-term stable operation and monitoring reliability of the monitoring equipment 100.

[0036] Figure 2 This is a schematic diagram of the tunnel lining crack monitoring device in an embodiment of the present invention.

[0037] like Figure 1-2 As shown, the monitoring device 100 in this embodiment includes a crack detection unit 8 and a support unit.

[0038] The support unit includes a central rotating shaft 6, a support assembly 90, and a support spring 7. A mounting groove 1 is provided on the arch of the tunnel lining, extending along the tunnel excavation direction. The central rotating shaft 6 is set in the mounting groove 1 through a mounting hook 5 and is slidably connected to the mounting groove 1 through a transmission device. It is used to drive the crack detection unit 8 to move along the tunnel axis, so as to realize continuous detection of cracks in the tunnel lining.

[0039] Figure 3 This is a schematic diagram of the support unit in an embodiment of the present invention.

[0040] like Figure 3 As shown, the support components 90 are rotatably disposed on both sides of the central pivot 6. Specifically, the support components 90 on both sides of the central pivot 6 can be folded around the central pivot 6 to reduce the volume of the support components 90 during transportation and storage.

[0041] The support assembly 90 is formed by combining multiple support frames 9. Adjacent support frames 9 on the same side are slidably connected by unit rollers 11 and can be unfolded to match the shape of the tunnel. When all the support frames 9 on both sides of the central pivot 6 are fully unfolded, the support assembly 90 is semi-circular, matching the shape of the tunnel.

[0042] Specifically, when the support assembly 90 needs to be folded and stored, it starts from the bottommost support frame 9 and rolls sequentially along the unit rollers 11 between adjacent support frames 9, gradually folding it down to the dome position. Subsequently, the support frames 9 on both sides rotate inwards (towards each other) around the central pivot 6, significantly reducing the overall volume of the support assembly 90. This structural design facilitates the storage and transportation of the support assembly 90, effectively reducing warehousing and transportation costs, while also minimizing the risk of damage during transportation due to excessive size, thereby improving reliability and economy.

[0043] Figure 4 This is a schematic diagram of the usage state of the prestressed spring in an embodiment of the present invention.

[0044] like Figure 4As shown, a prestressed spring 10 is also provided at the connection between adjacent support frames 9 on the same side. In this embodiment, the prestressed spring 10 is provided on both sides of the support frame 9. When the two ends of the prestressed spring 10 are not connected to the lower support frame 9, the prestressed spring 10 is in its initial state and is not deformed by external force. When the two ends of the prestressed spring 10 are connected to the lower support frame 9, the prestressed spring 10 deforms, and its internal tension causes the tail end of the lower support frame 9 to rise. At this time, the spring bears the weight of the lower support frame 9.

[0045] When the monitoring device 100 is installed inside the tunnel, if the upward angle of the tail end of the support frame 9 is too large, it will be constrained by the tunnel lining. The tunnel lining exerts a reaction force on the tail end of the support frame 9, causing it to gradually conform to the inner surface of the tunnel lining. Through this design, each support frame 9 can automatically adjust its posture according to the shape of the lining, achieving a tight fit with the inner wall of the tunnel lining of different curvatures and sizes. Therefore, the monitoring device 100 has good versatility and adaptability, and can be applied to various types of tunnel structures.

[0046] The support spring 7 is located at the lower part of the support frame 9 on both sides closest to the central pivot 6, corresponding to the position of the central pivot 6. When the support frame 9 on both sides of the central pivot 6 is unfolded, the support spring 7 can support the support frame 9 on both sides.

[0047] In the prior art, the general support structure is a fixed locking structure. However, in this embodiment, the high-performance support spring 7 is used instead of the fixed locking structure because different tunnels have different cross-sectional dimensions and arch curvatures. By using the spring support method, the overall structure of the monitoring device 100 can adaptively fit the inner wall of tunnels of different sizes and shapes, thereby improving versatility and adaptability.

[0048] Multiple crack detection units 8 are installed on the support component 90. The number and spacing of the crack detection units 8 can be flexibly configured according to the detection requirements: when rapid detection is required, multiple crack detection units 8 can be densely arranged to achieve comprehensive detection of the tunnel cross section; when cost reduction is the primary goal, only a small number of crack detection units 8 can be installed, and they can be moved back and forth on the support component 90 to complete the detection. Through the above structure and configuration, the monitoring device 100 maintains detection accuracy while taking into account economy and applicability.

[0049] Figure 5 This is a schematic diagram of the crack detection unit in an embodiment of the present invention.

[0050] like Figure 5As shown, the crack detection unit 8 includes a coarse detection unit 12, a medium detection unit 13, and a fine detection unit 14. These three units differ in size, component density, and measurement accuracy. Through a tiered configuration, energy saving, cost reduction, and improved detection efficiency can be achieved.

[0051] In this embodiment, the coarse detection unit 12 is rectangular and includes a large base plate 151, a large flow meter 15, and a large sealing ring 152. The large sealing ring 152 is disposed on the large base plate 151 and matches the shape of the edge of the large base plate 151. The large flow meter 15 is located inside the large sealing ring 152. The large flow meter 15 is disposed in the middle of the large base plate 151.

[0052] The large base plate 151 of the coarse exploration unit 12 has a large area, which can cover a large area of ​​the inner surface of the tunnel lining at one time. For tunnels with few cracks, most areas do not have obvious cracks, and the coarse exploration unit 12 can be used for rapid detection. The unit is equipped with only one large flow meter 15 for monitoring airflow. Its structure is simple and low cost, making it suitable for large-scale preliminary screening.

[0053] The intermediate probe unit 13 is about 1 / 4 the size of the coarse probe unit 12 and is rectangular. The intermediate probe unit 13 includes a medium-sized base plate 161, eight medium-sized flow meters 16, a hygrometer 18, and a medium-sized sealing ring 162.

[0054] A medium-sized sealing ring 162 is disposed on a medium-sized base plate 161 and matches the shape of the edge of the medium-sized base plate 161. A hygrometer 18 and eight medium-sized flow meters 16 are located inside the medium-sized sealing ring 162.

[0055] Eight medium-sized flow meters 16 are mounted on a medium-sized base plate 161 and are evenly distributed along the edge of the base plate 161. A hygrometer 18 is also mounted on the medium-sized base plate 161, located in the middle of the eight medium-sized flow meters 16.

[0056] Compared to the fine detection unit 14, the intermediate detection unit 13 is equipped with a greater number of medium-sized flow meters 16 and adds a high-precision humidity meter 18. When the coarse detection unit 12 detects a local flow velocity anomaly, the intermediate detection unit 13 and the fine detection unit 14 are automatically activated for further detection to determine the specific location and path of the crack and other characteristic parameters. Since smaller sensor sizes result in higher manufacturing and packaging costs, more sensors are arranged in the intermediate detection unit 13 to balance accuracy and cost.

[0057] The fine probe unit 14 is about 1 / 9 the size of the medium probe unit 13 and is rectangular. The fine probe unit 14 includes a miniature base plate 171, four miniature flow meters 17 and a miniature sealing ring 172.

[0058] A miniature sealing ring 172 is disposed on a miniature base plate 171, and its shape matches the edge of the miniature base plate 171. Four miniature flow meters 17 are located inside the miniature sealing ring 172. The four miniature flow meters 17 are disposed on the miniature base plate 171 and are evenly distributed.

[0059] The fine-tuning unit 14 is mainly used for the precise location and orientation determination of identified cracks. The fine-tuning unit 14 is equipped with four miniature flow meters 17, which can calculate eight spatial orientations of the cracks using multi-point wind speed data. This gradient detection method can significantly reduce energy consumption and manufacturing costs while ensuring detection accuracy, enabling adaptive detection for different tunnel shapes and sizes.

[0060] The coarse exploration unit 12, medium exploration unit 13, and fine exploration unit 14 are all equipped with elastic sealing rings (large sealing ring 152, medium sealing ring 162, and micro sealing ring 172) and base plates (large base plate 151, medium base plate 161, and micro base plate 171). The base plates are used to install and fix various sensors and provide them with basic support. The elastic sealing rings surround the base plates and have a certain degree of elasticity, allowing them to deform freely to adapt to the different curvatures of the tunnel lining walls. When the elastic sealing rings are tightly fitted to the tunnel lining walls, they can effectively eliminate gaps between each unit and the lining, preventing external air from seeping in through the contact surface. As a result, the airflow detected by various flow meters is only the airflow transmitted through the cracks, thus accurately reflecting the existence and permeability of the cracks.

[0061] This embodiment also provides a method for monitoring tunnel lining cracks, implemented using a tunnel lining crack monitoring device 100, comprising the following steps:

[0062] Step S1 is the coarse detection step. When the tunnel lining crack monitoring equipment 100 is started, the coarse detection unit 12 is used to perform the first detection. This unit monitors the changes in airflow in the tunnel through a large flow meter 15 to determine whether cracks exist. When a local flow velocity abnormality is detected, the existence of cracks is automatically identified, the crack area is determined, and the intermediate detection unit 13 and fine detection unit 14 are started for more precise detection.

[0063] Step S2 is the mid-range detection and traversal step, which divides the crack area into multiple zones. The mid-range detection unit 13 is used to further detect and locate the cracks within these zones. This unit uses eight medium-sized flow meters 16 and hygrometers 18 to detect airflow and ambient humidity, thereby pinpointing the specific location, size, and potential seepage or water inrush risk of the cracks, and ultimately determining the distribution range of the cracks. Specifically:

[0064] Figure 6 This is a schematic diagram illustrating the combined working principle of the coarse probe unit and the intermediate probe unit in an embodiment of the present invention.

[0065] like Figure 6As shown, when the large flow meter 15 in the coarse detection unit 12 detects airflow, it can be determined that a crack exists within its detection range. The size of the intermediate detection unit 13 is approximately one-quarter of that of the coarse detection unit 12, therefore the detection area (i.e., the crack area) of the coarse detection unit 12 can be divided into four zones: A, B, C, and D. The intermediate detection unit 13 sequentially detects and locates the cracks in zones A, B, C, and D to determine the specific distribution range of the cracks. Assuming that the detection results show no airflow in zones C and D, but airflow signals in zones A and B, it can be preliminarily determined that the crack penetrates areas A and B.

[0066] Figure 7 This is a schematic diagram illustrating the combined working principle of the intermediate probe unit and the fine probe unit in an embodiment of the present invention.

[0067] like Figure 7 As shown, the intermediate detection unit 13 is equipped with nine sensors, including a hygrometer 18 in the center and eight medium-sized flow meters 16. During the zone detection process, the hygrometer 18 simultaneously collects ambient humidity data; if an abnormal humidity is detected, it indicates a potential risk of water seepage or gushing, and the corresponding information is reported to the monitoring center. When the intermediate detection unit 13 detects in zone A, the positions corresponding to the eight medium-sized flow meters 16 are numbered A1 to A9 (A5 is missing); when detecting in zone D, the corresponding positions are numbered D1 to D9 (D5 is missing). When abnormal airflow is observed at positions A1, A8, D2, and D9, it can be determined that the crack's direction roughly extends from A1 to A8, and then to areas D2 and D9. Through the above detection and analysis process, the correlation between the crack direction and the response positions of the medium-sized flow meters 16 can be identified, providing a basis for the subsequent precise measurement of the fine detection unit 14.

[0068] Step S3 is the detailed exploration and active tracking step. After the coarse exploration unit 12 and the intermediate exploration unit 13 confirm the existence and preliminary location of the crack, the detailed exploration unit 14 will perform precise location in active tracking mode. This unit uses a micro flow meter 17 to track the direction and extension path of the crack point by point. The detailed exploration unit 14 moves gradually within the distribution range of cracks in a zone, detects the expansion range of cracks in real time, checks the development path of cracks in turn, determines the precise direction of cracks, and repeats this step until the precise direction of cracks in all zones is determined. Specifically:

[0069] Figure 8 This is a schematic diagram illustrating the active tracking working principle of the fine-tuning unit in an embodiment of the present invention.

[0070] The size of the fine detection unit 14 is approximately one-ninth that of the medium detection unit 13. Unlike the medium detection unit 13, which scans zones sequentially, the fine detection unit 14 employs an "active tracking" mode for precise detection. Figure 8As shown, based on the previous detection results, it can be determined that the crack extends roughly from position A1 to A8, and then to areas D2 and D9. Taking area A as an example, the crack enters from position A1 in the upper left corner and exits from position A8 in the lower middle. First, the fine probe unit 14 is placed at position A1 for detection. At this time, airflow response is detected in the upper left and lower right of the four micro flow meters 17, indicating that the crack direction is from the upper left to the lower right. Since the upper left direction is outside the area of ​​area A, the fine probe unit 14 is moved one unit in the lower right direction and the detection continues. Subsequently, if the detection result shows that the lower right micro flow meter 17 shows airflow response again, it indicates that the crack extends further in this direction. The fine probe unit 14 continues to move one unit to the lower right and repeats the detection. When the two lower micro flow meters 17 are detected to respond simultaneously, it can be determined that the crack turns from the lower right to the lower direction. The fine probe unit 14 is then moved one unit downwards in the vertical direction and continues to track until it reaches position A8. Similarly, in zone D, the crack enters at position D2 and exits at position D9. Using the same tracing process, the precise path of the crack within zone D can be obtained.

[0071] Step S4 is the crack image stitching and data aggregation step. The direction of cracks in all zones is aggregated, stitched into a complete crack image, and the crack parameters are transmitted to the monitoring center. Specifically:

[0072] By summarizing the fracture paths of the four zones A, B, C, and D and stitching the images together, a complete fracture development image of the area covered by coarse exploration unit 12 can be obtained, thereby achieving precise location and visual identification of fracture paths.

[0073] Figure 9 This is a schematic diagram of the detection range of the crack detection unit in an embodiment of the present invention.

[0074] Specifically, the detection range of each level of crack detection unit 8 is, for example... Figure 9 As shown, the detection range of nine fine detection units 14 is equivalent to that of one medium detection unit 13, and the detection range of four medium detection units 13 is equivalent to that of one coarse detection unit 12. With this configuration, the various levels of fracture detection units 8 can achieve effective area coverage at different scales.

[0075] The parameters of a crack include: airflow change rate, airflow velocity, crack type, crack location, and crack length.

[0076] Step S5 is the evaluation step. Based on the crack image and crack parameters, the crack is evaluated according to preset standards to determine whether intervention is needed, thus completing the preliminary monitoring process. Specifically:

[0077] Figure 10 This is a schematic diagram illustrating the safety assessment of tunnel lining cracks based on machine learning technology in an embodiment of the present invention.

[0078] All crack detection units 8 collect and report monitoring data in real time to the monitoring center. The monitoring center summarizes information such as airflow data, humidity data, crack location and direction, and conducts a preliminary assessment based on set standards or expert input. Based on the set standards, if the crack is in a dangerous area or continues to expand, an alarm will be issued, and repair and reinforcement will be recommended. Alternatively, experts will determine whether continued observation is necessary, whether it has no impact on the tunnel structure, and whether immediate repair is required, completing the preliminary monitoring process. Simultaneously, machine learning technology can be used to continuously learn about the cracks, thereby assisting experts in assessing the overall safety and risk level of the tunnel lining. Figure 10 As shown, based on the obtained crack characteristic data such as airflow change rate, airflow velocity, expert evaluation, crack type, location and length, a method for assessing the safety of tunnel lining cracks based on airflow changes can be realized through machine learning technology.

[0079] Step S6 is the continuous monitoring and periodic verification step. After the initial monitoring process is completed, the regular continuous monitoring mode will be entered. The coarse detection unit 12 is set to periodically return to the same crack area for re-examination. If the coarse detection unit 12 detects airflow, but the airflow value is similar to the recorded value in S1, it is determined that the crack has not expanded further, and the original assessment result is maintained, without needing to restart the intermediate detection unit 13 and the fine detection unit 14. If the airflow shows a significant increase or change compared to the recorded value in S1, it is determined that the crack has expanded further or its characteristics have changed, and S1-S6 are repeated to monitor the crack. This design not only saves time and energy but also reduces the number of expert consultations.

[0080] The monitoring equipment 100 is connected to the tunnel lighting power supply to achieve continuous acquisition and automatic transmission of crack characteristic data.

[0081] In addition, in energy-saving mode, the monitoring device 100 uses flow meters of all levels (large flow meter 15, medium flow meter 16, and micro flow meter 17) only to detect the airflow naturally passing through the crack. When higher precision detection is required, it can switch to data enhancement mode. In this mode, the internal components of the crack detection units 8 can be operated by vacuuming, enhancing the crack airflow capture capability. Even the smallest cracks can generate sufficient airflow to ensure that the flow meters of all levels can capture and monitor them.

[0082] Thus, the monitoring equipment 100 has achieved the monitoring of tunnel lining cracks.

[0083] The role and effect of the embodiments

[0084] The tunnel lining crack monitoring device 100 and method according to the present invention have the following beneficial effects:

[0085] (1) Long-term: The monitoring equipment 100 is set in the safety belt between the tunnel construction limit 2 and the outline 4 of the tunnel lining wall. It does not occupy the passage space, and reduces external collisions and operational interference. It can be fixed for a long time and is suitable for carrying out time history data accumulation and trend judgment.

[0086] (2) Continuous: The monitoring equipment 100 moves along the tunnel axis through the mounting slot 1 to achieve continuous travel detection; the three-level crack detection unit 8 of coarse-medium-fine crack detection works in turn according to the gradient process of triggering-traversing-active tracking, and can complete continuous monitoring from discovery to location within the same inspection cycle.

[0087] (3) Wide area: By setting up coarse exploration units 12, medium exploration units 13 and fine exploration units 14 on multiple support frames 9 as needed, the large area coverage advantage of coarse exploration units 12 is used for rapid scanning. Through the scale correlation between coarse, medium and fine exploration units, different scale mapping is carried out, which can realize efficient surface coverage and multi-scale splicing imaging of the entire tunnel, and realize accurate positioning and visual identification of tunnel lining cracks.

[0088] (4) General Purpose: Prestressed springs 10 are installed between adjacent support frames 9. When the two ends of the prestressed springs 10 are connected to the support frames 9 below, the prestressed springs 10 deform, and the internal tension causes the tail end of the support frame 9 below to rise. If the angle of the tail end of the support frame 9 rises too much, it will be constrained by the tunnel lining. The tunnel lining applies a reaction force to the tail end of the support frame 9, causing it to gradually fit against the inner surface of the tunnel lining. Through this design, each support frame 9 can automatically adjust its posture according to the shape of the lining, achieving a tight fit with the inner wall of the tunnel lining with different curvatures and sizes. With the elastic sealing rings of the crack detection units 8 at each level, the monitoring equipment 100 can adapt to different cambers and curvatures, fit various cross sections and sizes, and achieve adaptive monitoring of different types of tunnels.

[0089] (5) Anti-interference: The sealing rings at all levels fit the tunnel lining, which can effectively eliminate the leakage of airflow from the contact gaps, so that the flow meters at all levels can only sense the ventilation signal of the cracks and are not affected by environmental factors such as electromagnetic noise and temperature difference; at the same time, the “data enhancement (vacuum)” mode can be switched when needed to improve the detectability and signal-to-noise ratio of weak ventilation cracks.

[0090] (6) High Reliability: The monitoring equipment 100 adopts mature components and is equipped with a safety belt between the tunnel's construction clearance 2 and the tunnel lining inner wall contour 4. This ensures the installation safety and structural stability of the monitoring equipment 100, and effectively avoids collisions and interference from vehicle operation and maintenance work, thereby guaranteeing the long-term stable operation and monitoring reliability of the monitoring equipment 100. During operation, the monitoring equipment 100 reduces the false judgment rate through multi-level triggering and repeated verification, resulting in high overall reliability. The support components 90 on both sides of the central rotating shaft 6 can be folded by rotating around the central rotating shaft 6, significantly reducing the overall volume of the support components 90 and minimizing the risk of damage during handling.

[0091] (7) Easy to maintain: The central rotating shaft 6 is foldable, the structural design is simple, the support component 90 can be stored, and the structure is modular. The crack detection unit 8 is set on the support frame 9 and can be replaced / added or removed, which is convenient for maintenance and expansion as needed. The overall axial track arrangement of the monitoring equipment 100 also facilitates daily maintenance and online replacement.

[0092] (8) Low cost: This invention uses a coarse unit for low-cost large-area initial screening, a medium unit for verification with an appropriate number of medium-sized flow meters 16, and a fine unit for precise measurement with a small number of micro flow meters 17, which significantly reduces the investment and energy consumption of flow meters per unit area. At the same time, it reduces the renovation expenses and operation and maintenance costs by utilizing the tunnel lighting power supply and traffic conditions.

[0093] Furthermore, the tunnel lining crack monitoring method proposed in this invention achieves a graded monitoring mechanism from rapid screening to accurate identification through a gradient monitoring mode, namely, the coordinated work of three levels of crack detection units: coarse, medium, and fine. This can significantly shorten the monitoring cycle, reduce energy consumption and costs, and improve crack identification efficiency and monitoring intelligence.

[0094] Those skilled in the art should understand that this invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to this invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A tunnel lining crack monitoring device, characterized in that, Located between the tunnel's structural clearance and the outline of the tunnel lining, including: The crack detection unit is used to collect characteristic data of tunnel lining cracks in order to monitor the cracks in the tunnel lining. Support unit, including: Central pivot; A support assembly, rotatably mounted on both sides of the central pivot, is formed by combining multiple support frames. Adjacent support frames on the same side are slidably connected and can be deployed to match the shape of the tunnel. The crack detection unit includes a coarse detection unit, a medium detection unit, and a fine detection unit. The size of the medium detection unit is no greater than 1 / 4 of the size of the coarse detection unit, and the size of the fine detection unit is no greater than 1 / 9 of the size of the medium detection unit. The coarse detection unit, the medium detection unit, and the fine detection unit are mounted on multiple support frames.

2. The tunnel lining crack monitoring device according to claim 1, characterized in that: in, The tunnel lining is provided with a mounting groove that extends along the tunnel excavation direction. The central rotating shaft is set in the mounting groove via a mounting hook and is slidably connected to the mounting groove. It is used to drive the coarse exploration unit, the intermediate exploration unit and the fine exploration unit to move along the tunnel axis to detect the cracks.

3. The tunnel lining crack monitoring device according to claim 1, characterized in that: in, The support unit also includes a support spring, which is disposed on the support frame and corresponds to the position of the central rotating shaft, and is used to support the support frames on both sides.

4. The tunnel lining crack monitoring device according to claim 1, characterized in that: in, The adjacent support frames located on the same side are slidably connected by unit rollers.

5. The tunnel lining crack monitoring device according to claim 1, characterized in that: in, A prestressed spring is provided between adjacent support frames located on the same side.

6. The tunnel lining crack monitoring device according to claim 1, Its features are: in, The coarse detection unit includes: Large base plate; A large flow meter is mounted on the large base plate; A large sealing ring is disposed on the large base plate and matches the shape of the edge of the large base plate. The large flow meter is located inside the large sealing ring.

7. The tunnel lining crack monitoring device according to claim 1, Its features are: in, The probe unit includes: Medium-sized base plate; Multiple medium-sized flow meters are mounted on the medium-sized base plate; A hygrometer is mounted on the medium-sized base plate; A medium-sized sealing ring is disposed on the medium-sized base plate and matches the shape of the edge of the medium-sized base plate. The hygrometer and a plurality of the medium-sized flow meters are located inside the medium-sized sealing ring.

8. The tunnel lining crack monitoring device according to claim 1, Its features are: in, The fine probe unit includes: Miniature base plate; Multiple miniature flow meters are mounted on the miniature base plate; A miniature sealing ring is disposed on the miniature base plate and matches the shape of the edge of the miniature base plate. Multiple miniature flow meters are located inside the miniature sealing ring.

9. A method for monitoring tunnel lining cracks, implemented based on the tunnel lining crack monitoring equipment described in claims 1-8, characterized in that, Includes the following steps: S1: Coarse exploration step, using the coarse exploration unit to monitor the changes in airflow in the tunnel, to determine whether the crack exists, when a local flow velocity abnormality is detected, the existence of the crack is automatically identified, the crack area is determined, and the intermediate exploration unit and the fine exploration unit are activated for detection; S2: The mid-probing and traversal step divides the crack area into multiple partitions, and uses the mid-probing unit to further detect and locate the cracks within the multiple partitions to determine the distribution range of the cracks; S3: Detailed exploration and active tracking steps: Using the detailed exploration unit, move step by step within the distribution range of the cracks in a partition, check the development path of the cracks in turn, determine the direction of the cracks, and repeat this step until the direction of the cracks in all the partitions is determined. S4: Crack image stitching and data aggregation step: The direction of the cracks in all the partitions is aggregated, stitched into a complete crack image, and the crack parameters are transmitted to the monitoring center. S5: Evaluation step: Based on the crack image and the crack parameters, evaluate the crack according to preset standards, determine whether intervention is required, and complete the preliminary monitoring process. S6: Continuous monitoring and periodic verification steps. After the preliminary monitoring process is completed, the coarse detection unit is set to periodically return to the same crack area for re-examination. If the coarse detection unit detects airflow, but it is similar to the recorded value of the airflow in S1, it is determined that the crack has not expanded further, and the original evaluation result is maintained. If the airflow is significantly enhanced or changed compared with the recorded value of the airflow in S1, it is determined that the crack has expanded further or its characteristics have changed. Then, S1-S6 are repeated to monitor the crack.

10. The method for monitoring tunnel lining cracks according to claim 9, characterized in that: in, In S4, the parameters of the crack include: airflow change rate, airflow velocity, crack type, crack location, and crack length.

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