Tunnel safety early warning device and method based on distributed optical fiber sensing

Abstract

The invention discloses a tunnel safety early warning device and method based on distributed optical fiber sensing, and relates to the technical field of tunnel strain monitoring devices.The tunnel safety early warning device comprises a cloud server, an optical fiber connected with the cloud server and a plurality of detection frames arranged in a tunnel, the optical fiber is electrically connected with a plurality of sensors, and the cloud server is connected with an alarm device. A detection plate is movably arranged on the detection frame, the detection plate and the detection frame are connected through a reset spring, a crimping block is arranged on the detection plate, a connecting block is fixedly arranged on the crimping block, the sensor is fixedly connected to the connecting block, a plurality of detection probes are further arranged on the detection frame, and the detection probes are inserted into the tunnel wall of the tunnel in a penetrating mode. The detection probe abuts against the outer side wall of the detection plate. According to the invention, while the sensitivity of strain detection in the tunnel is ensured, the convenience of optical fiber installation and later maintenance is improved.

Description

Technical Field

[0001] This application relates to the technical field of tunnel strain monitoring devices, and in particular to a tunnel safety early warning device and method based on distributed optical fiber sensing. Background Technique

[0002] The technical principle of tunnel distributed optical fiber sensing for detecting tunnel strain is mainly based on some unique properties of optical fibers, such as the characteristics of light propagation in optical fibers and the sensitivity of optical fibers. This technology utilizes optical phenomena such as Brillouin scattering or Raman scattering. Specifically, when an optical pulse propagates in an optical fiber, it interacts with acoustic phonons in the optical fiber, generating Brillouin scattering. This scattering causes a change in the frequency of the optical signal, and this frequency change has a direct relationship with physical quantities such as strain and temperature in the optical fiber. By measuring this frequency change, the strain suffered by the optical fiber can be deduced.

[0003] In tunnel strain detection, the optical fiber is laid on the surface or inside of the tunnel structure. When the tunnel deforms, the optical fiber will also deform accordingly, thereby changing the optical signal propagation characteristics therein. Through a distributed optical fiber sensing system, this change can be monitored in real time, and the strain distribution of the tunnel can be inferred accordingly.

[0004] Currently, when laying optical fibers in a tunnel, in order to improve the sensitivity of strain detection at different positions in the tunnel, it is usually necessary to lay multiple optical fibers in the tunnel. The installation and fixation of the optical fibers are very inconvenient and not conducive to later maintenance. Summary of the Invention

[0005] Aiming at the problems existing in the prior art, this application provides a tunnel safety early warning device and method based on distributed optical fiber sensing.

[0006] In the first aspect, a tunnel safety early warning device based on distributed optical fiber sensing provided by this application adopts the following technical solution: A tunnel safety early warning device based on distributed optical fiber sensing includes a cloud server, an optical fiber connected to the cloud server, and a plurality of detection frames arranged in the tunnel. A plurality of sensors are electrically connected to the optical fiber, and the cloud server is connected to an alarm device. Each of the detection frames is distributed along the extension direction of the tunnel. A connection component for fixedly connecting the optical fiber is provided on each detection frame. A detection plate is movably arranged on the detection frame, and the detection plate is connected to the detection frame through a return spring. A pressing block is provided on the detection plate, and a connecting block is fixedly provided on the pressing block. The sensor is fixedly connected to the connecting block. A plurality of detection probes are further provided on the detection frame. The detection probes penetrate into the tunnel wall of the tunnel, and the detection probes are in contact with the outer side wall of the detection plate.

[0007] Optionally, the connection component includes a pressing plate hinged to the detection frame and a bolt for fixing the pressing plate to the detection frame, and a clamping groove adapted to the optical fiber is provided on the pressing plate.

[0008] Optionally, a rubber pad is provided in the clamping groove.

[0009] Optionally, the crimping block is movably arranged on the detection plate and is located on the side of the detection plate away from the detection probe. The crimping block is connected to the detection plate through a connecting spring. A limiting sleeve is fixedly arranged on the detection frame. The crimping block slidably penetrates through the limiting sleeve. A first limiting plate and a second limiting plate are fixedly arranged on the crimping block, and the first limiting plate and the second limiting plate are respectively arranged on both sides of the limiting sleeve.

[0010] Optionally, the detection probe includes a detection section and a sensing section. The detection section is used to penetrate into the tunnel wall, and the sensing section is slidably arranged on the detection section along the length direction of the detection section. A limiting component for preventing the sensing section from sliding is provided on the detection section.

[0011] Optionally, a first elastic member for driving the sensing section to slide away from the detection section is provided on the detection section.

[0012] Optionally, the limiting component includes a top cylinder, a limiting block and a locking nut. The top cylinder is slidably sleeved on the detection section. The limiting block is fixedly arranged on the side wall of the sensing section, and the top cylinder is used to abut against the limiting block. An external thread is provided on the side wall of the detection section. The locking nut is sleeved on the detection section and is in threaded cooperation with the detection section. The locking nut is arranged on the side of the top cylinder away from the limiting block.

[0013] Optionally, two limiting strips are fixedly arranged on the outer side wall of the detection plate. Both limiting strips extend along the plate surface of the detection plate, and the two limiting strips are arranged at intervals. The sensing section of the detection probe penetrates into the gap between the two limiting strips.

[0014] Optionally, buffer plates are slidably arranged on the side of the two limiting strips close to each other. The two buffer plates are respectively arranged on both sides of the sensing section. A second elastic member is arranged between the limiting strip and the corresponding buffer plate. The second elastic member is used to drive the buffer plate to abut tightly against the sensing section.

[0015] Second, this application provides a working method for a tunnel safety early warning device based on distributed optical fiber sensing, and adopts the following technical solutions: A working method for a tunnel safety early warning device based on distributed optical fiber sensing includes the following steps: S1. When deformation occurs at a certain area position in the tunnel, the detection probe at this position displaces; S2. The longitudinal strain is directly transmitted to the detection board through the detection probe, driving the detection board to move. The connection spring drives the crimping block to move. The transverse strain drives the detection board to move through the limiting strips on both sides of the detection probe, and then drives the crimping block to move through the connection spring. S3. As the crimping block moves, the signal is transmitted to the optical fiber through the sensor, causing the vibration frequency of the Rayleigh backscattered wave generated by the glass lattice of the optical fiber at this position to change. By measuring this frequency change, the strain on the optical fiber can be calculated and fed back to the cloud server in a timely manner, thereby inferring the strain distribution of the tunnel and achieving precise detection of strain occurring at different positions in the tunnel. S4. When the frequency change at a certain position of the light exceeds a predetermined value, the cloud server is used to control the alarm device for safety warning.

[0016] In summary, the present application includes at least one of the following beneficial technical effects: 1. Install and fix several detection frames in the tunnel, fix the optical fiber on each detection frame, and fixedly connect the sensor to the connection block on the crimping block. Insert each detection probe into the tunnel wall of the tunnel, and make one end of the detection probe abut against the surface of the detection board. When deformation occurs at a certain area position in the tunnel, the detection probe at this position displaces, driving the detection board to move, the crimping block displaces, and the strain is transmitted to the optical fiber through the sensor. The optical fiber will also deform accordingly, causing the vibration frequency of the Rayleigh backscattered wave generated by the glass lattice of the optical fiber at this position to change. By measuring this frequency change, the strain on the optical fiber can be calculated and fed back to the cloud server in a timely manner, thereby inferring the strain distribution of the tunnel and achieving precise detection of strain occurring at different positions in the tunnel. When the frequency change at a certain position of the light exceeds a predetermined value, the cloud server is used to control the alarm device for safety warning. And only one optical fiber needs to be set in the tunnel, improving the convenience of optical fiber installation and facilitating later maintenance.

[0017] 2. In the present application, the crimping block is movably arranged on the detection board and connected to the detection board through a connection spring. When the detection board moves, the connection spring drives the crimping block to move. By sliding the crimping block through the limiting sleeve and respectively arranging a first limiting plate and a second limiting plate on both sides of the limiting sleeve, the displacement amount of the crimping block is controlled to prevent the optical fiber from breaking due to excessive displacement of the crimping block.

[0018] 3. In the present application, two limiting strips are arranged on the detection board, and the sensing section of the detection probe is inserted into the gap between the two limiting strips. When lateral strain occurs in the tunnel, the detection probe drives the detection board to move through the limiting strips on both sides, realizing the detection of the lateral strain of the tunnel. Description of the Drawings

[0019] Figure 1 is the circuit block diagram of the embodiment of the present application; Figure 2 is the overall structure schematic diagram of the embodiment of the present application; Figure 3 is the structure schematic diagram for expressing the connection components of the embodiment of the present application; Figure 4 is Figure 3 the enlarged view of part A in Figure 5 is the structure schematic diagram for expressing the detection board of the embodiment of the present application; Figure 6 is the structure schematic diagram for expressing the detection probe of the embodiment of the present application.

[0020] Explanation of reference numerals: 1, cloud server; 2, optical fiber; 21, sensor; 3, alarm device; 4, detection rack; 41, pressing plate; 42, bolt; 43, rubber pad; 44, limiting sleeve; 5, detection board; 51, return spring; 52, crimping block; 521, connecting block; 522, first limiting plate; 523, second limiting plate; 53, connecting spring; 54, limiting strip; 55, buffer board; 56, second elastic member; 6, detection probe; 61, detection section; 611, sliding groove; 612, first elastic member; 613, top cylinder; 614, locking nut; 62, sensing section; 621, limiting block. Detailed implementation manners

[0021] The following further elaborates on the present application in conjunction with the attached Figure 1 - attached Figure 6 drawings for a more detailed description.

[0022] The embodiment of the present application discloses a tunnel safety early warning device based on distributed optical fiber sensing. Referring to Figure 1 and Figure 2 , it includes a cloud server 1, an optical fiber 2 connected to the cloud server 1, and an alarm device 3. The alarm device 3 uses an audible and visual alarm, and a plurality of alarm devices 3 are provided, and each alarm device 3 is distributed in the tunnel. A plurality of sensors 21 are electrically connected to the optical fiber 2.

[0023] Referring to Figure 2 , a plurality of detection racks 4 are distributed in the tunnel along the extension direction of the tunnel. The detection racks 4 are fixed on the ground in the tunnel. The distance between two adjacent detection racks 4 is determined according to the rock formation structure of the tunnel wall. If the rock formation structure of the tunnel wall is relatively stable, the distance between the two detection racks 4 can be appropriately increased.

[0024] Referring to Figure 3 and Figure 4, on each detection frame 4, a connection component for fixedly connecting the optical fiber 2 is provided. The connection component is set in two groups and is arranged on both sides of the detection frame 4 respectively. The connection component includes a pressing plate 41 hinged on the detection frame 4 and a bolt 42 for fixing the pressing plate 41 on the detection frame 4. A clamping groove adapted to the optical fiber 2 is provided on the pressing plate 41, and a rubber pad 43 is arranged in the clamping groove.

[0025] Refer to Figure 3 and Figure 5 , a detection plate 5 is movably arranged on the detection frame 4. The cross-section of the detection plate 5 is arc-shaped and is arranged at an interval from the tunnel wall. A plurality of reset springs 51 are arranged along the circumference of the detection plate 5 on the detection plate 5. One end of the reset spring 51 is fixedly connected to the detection plate 5, and the other end of the reset spring 51 is fixedly connected to the detection frame 4. A plurality of detection probes 6 are also arranged on the detection frame 4 and above the detection plate 5. Each detection probe 6 is distributed along the arc surface of the detection plate 5; the detection probes 6 are all inserted into the tunnel wall of the tunnel, and the detection probes 6 are in contact with the surface of the detection plate 5.

[0026] Refer to Figure 3 and Figure 5 , a pressing block 52 is movably arranged on the detection plate 5. The pressing block 52 is connected to the detection plate 5 through a connecting spring 53. Both ends of the connecting spring 53 are fixedly connected to the pressing block 52 and the detection plate 5 respectively. The sensors 21 correspond to the detection frames 4 one by one. A connecting block 521 is fixedly arranged on the pressing block 52, and the sensor 21 is fixedly connected to the connecting block 521 on the corresponding detection frame 4. A limiting sleeve 44 is fixedly arranged on the detection frame 4. The pressing block 52 slidably penetrates through the limiting sleeve 44. A first limiting plate 522 and a second limiting plate 523 are fixedly arranged on the pressing block 52. The first limiting plate 522 is located on the side of the limiting sleeve 44 close to the detection plate 5, and the second limiting plate 523 is located on the side of the limiting sleeve 44 far from the detection plate 5.

[0027] When deformation occurs at a certain area position in the tunnel, the detection probe 6 at this position undergoes displacement, drives the detection plate 5 to move, the pressing block 52 undergoes displacement, and transmits a signal to the optical fiber 2 through the sensor 21. The optical fiber 2 will also deform accordingly, resulting in a change in the vibration frequency of the Rayleigh backscattered wave generated by the glass lattice of the optical fiber 2 at this position. By measuring this frequency change, the strain received by the optical fiber 2 can be deduced and fed back to the cloud server 1 in a timely manner, and based on this, the strain distribution of the tunnel can be inferred to achieve precise detection of strain occurring at different positions in the tunnel. When the frequency change situation at a certain position of the optical fiber 2 exceeds a predetermined value, the cloud server 1 controls the alarm device 3 to give a safety warning.

[0028] Further, the crimping block 52 is movably arranged on the detection plate 5 and connected to the detection plate 5 through a connecting spring 53. When the detection plate 5 moves, the crimping block 52 is driven to move through the connecting spring 53. The crimping block 52 is slidably inserted into the limit sleeve 44, and a first limit plate 522 and a second limit plate 523 are respectively arranged on both sides of the limit sleeve 44, so as to control the displacement of the crimping block 52 and prevent the optical fiber 2 from breaking due to excessive displacement of the crimping block 52.

[0029] Referring to Figure 5 and Figure 6 , the detection probe 6 includes a detection section 61 and a sensing section 62. A sliding groove 611 is formed at the end of the detection section 61 along the length direction of the detection section 61. The sensing section 62 is slidably arranged in the sliding groove 611. A guiding block is fixedly arranged on the side wall of the sensing section 62. A guiding groove is formed on the side wall of the sliding groove 611 along the length direction of the detection section 61. The guiding block is slidably arranged in the guiding groove. The detection section 61 is inserted into the tunnel wall.

[0030] Referring to Figure 6 , a first elastic member 612 for driving the sensing section 62 to slide away from the detection section 61 is arranged on the detection section 61. The first elastic member 612 includes a first compression spring. The first compression spring is arranged in the sliding groove 611. One end of the first compression spring abuts against the bottom wall of the sliding groove 611, and the other end of the first compression spring abuts against the sensing section 62.

[0031] Referring to Figure 6 , a limit assembly for preventing the sensing section 62 from sliding is arranged on the detection section 61. The limit assembly includes a top cylinder 613, a limit block 621 and a locking nut 614. The top cylinder 613 is slidably sleeved on the detection section 61. The limit block 621 is fixedly arranged on the side wall of the sensing section 62. An external thread adapted to the locking nut 614 is arranged on the side wall of the detection section 61. The locking nut 614 is sleeved on the detection section 61 and is in threaded cooperation with the detection section 61. The locking nut 614 is arranged on the side of the top cylinder 613 away from the limit block 621. When installing the detection probe 6, the detection section 61 is inserted into the tunnel wall. The sensing section 62 abuts against the detection plate 5 under the elastic force of the first compression spring. Then, by rotating the locking nut 614, the top cylinder 613 abuts against the limit block 621 to prevent the limit block 621 from moving towards the detection section 61, and the installation of the detection probe 6 can be completed. The detection probe 6 is convenient and fast to install, and can be adjusted according to the distance between the detection plate 5 and the tunnel wall, increasing the practicality.

[0032] Referring to Figure 5, two limiting strips 54 are fixedly arranged on the outer side wall of the detection board 5. Both limiting strips 54 extend along the board surface of the detection board 5, and the length directions of the two limiting strips 54 are parallel. The two limiting strips 54 are arranged at intervals. The sensing section 62 of the detection probe 6 is arranged in the gap between the two limiting strips 54. By arranging two limiting strips 54 on the detection board 5 and arranging the sensing section 62 of the detection probe 6 in the gap between the two limiting strips 54, when a lateral strain occurs in the tunnel, the detection probe 6 can drive the detection board 5 to move through the limiting strips 54 on both sides, realizing the detection of the lateral strain of the tunnel.

[0033] Refer to Figure 5 , buffer plates 55 are slidably arranged on one side of the two limiting strips 54 close to each other. A plurality of guide rods are fixedly arranged at one end of the two buffer plates 55 away from each other. The guide rods are slidably arranged on the corresponding limiting strips 54, and anti - detachment blocks are fixedly arranged at one end of each guide rod away from the buffer plate 55. Second elastic members 56 for driving the corresponding buffer plates 55 to slide and abut against the sensing section 62 are arranged on the two limiting strips 54. The second elastic member 56 includes a second compression spring. A second compression spring is sleeved on each guide rod. One end of the second compression spring abuts against the buffer plate 55, and the other end of the second compression spring abuts against the limiting strip 54. The sensing section 62 of the detection probe 6 is inserted between the two buffer plates 55.

[0034] Since when a strain occurs in the tunnel, the direction of the strain is uncertain, the displacement amounts and displacement directions of the detection probes 6 corresponding to the same detection frame 4 will be different. By inserting the sensing section 62 of the detection probe 6 between the two buffer plates 55, a certain lateral displacement amount is provided between the detection probe 6 and the detection board 5. And because the buffer plate 55 and the limiting strip 54 are supported by the second compression spring, when the detection probe 6 moves, it can also drive the detection board 5 to move, realizing the timely feedback of the optical fiber 2 to the strain.

[0035] The implementation principle of a tunnel safety warning device based on distributed optical fiber sensing in an embodiment of the present application is as follows: A number of detection frames 4 are installed and fixed in the tunnel, and the distance between adjacent two detection frames 4 is set according to the structural strength of the tunnel rock formation. The optical fiber 2 is fixed on each detection frame 4, and the sensor 21 is fixedly connected to the crimping block 52. The detection sections 61 of each detection probe 6 are all inserted into the tunnel wall of the tunnel, and the sensing section 62 of the detection probe 6 is abutted against the surface of the detection plate 5, and the sensing section 62 is inserted between two buffer plates 55. When deformation occurs at a certain area position in the tunnel, the detection probe 6 at this position displaces, drives the detection plate 5 to move, the crimping block 52 displaces, and transmits a signal to the optical fiber 2 through the sensor 21. The optical fiber 2 will also deform accordingly, resulting in a change in the vibration frequency of the Rayleigh backscattered wave generated by the glass lattice of the optical fiber 2 at this position. By measuring this frequency change, the strain received by the optical fiber 2 can be deduced and fed back to the cloud server 1 in a timely manner, thereby inferring the strain distribution of the tunnel and achieving precise detection of strains occurring at different positions in the tunnel. When the frequency change situation at a certain position of the optical fiber 2 exceeds a predetermined value, the cloud server 1 is used to control the alarm device 3 to give a safety warning. Moreover, only one optical fiber 2 needs to be set in the tunnel, which improves the convenience of installing the optical fiber 2 and is convenient for later maintenance.

[0036] An embodiment of the present application also discloses a working method of a tunnel safety warning device based on distributed optical fiber sensing, including the following steps: S1. When deformation occurs at a certain area position in the tunnel, the detection probe 6 at this position displaces; S2. The longitudinal strain is directly transmitted to the detection plate 5 through the detection probe 6, and drives the detection plate 5 to move, and drives the crimping block 52 to move through the connecting spring 53. The lateral strain drives the detection plate 5 to move through the limiting strips 54 on both sides of the detection probe 6, and then drives the crimping block 52 to move through the connecting spring 53; S3. As the crimping block 52 moves, a signal is transmitted to the optical fiber 2 through the sensor 21, resulting in a change in the vibration frequency of the Rayleigh backscattered wave generated by the glass lattice of the optical fiber 2 at this position. By measuring this frequency change, the strain received by the optical fiber 2 can be deduced and fed back to the cloud server 1 in a timely manner, thereby inferring the strain distribution of the tunnel and achieving precise detection of strains occurring at different positions in the tunnel; S4. When the frequency change situation at a certain position of the optical fiber 2 exceeds a predetermined value, the cloud server 1 is used to control the alarm device 3 to give a safety warning.

[0037] The above are all preferred embodiments of the present application. The protection scope of the present application is not limited thereby. Therefore, all equivalent changes made according to the structure, shape, and principle of the present application should be covered within the protection scope of the present application.

Claims

1. A tunnel safety early warning device based on distributed optical fiber sensing, characterized in that: It includes a cloud server (1), an optical fiber (2) connected to the cloud server (1), and a number of detection frames (4) arranged in the tunnel. A number of sensors (21) are electrically connected to the optical fiber (2). The cloud server (1) is connected to an alarm device (3). Each of the detection frames (4) is distributed along the extension direction of the tunnel. A connection component for fixedly connecting the optical fiber (2) is provided on each detection frame (4). A detection plate (5) is movably arranged on the detection frame (4), and the detection plate (5) is connected to the detection frame (4) through a return spring (51). A pressing block (52) is arranged on the detection plate (5), and a connection block (521) is fixedly arranged on the pressing block (52). The sensor (21) is fixedly connected to the connection block (521). A number of detection probes (6) are also arranged on the detection frame (4). The detection probes (6) penetrate into the tunnel wall of the tunnel, and the detection probes (6) are in contact with the outer side wall of the detection plate (5).

2. The tunnel safety warning device based on distributed optical fiber sensing according to claim 1, characterized in that: The connection component includes a pressing plate (41) hinged on the detection frame (4) and a bolt (42) for fixing the pressing plate (41) on the detection frame (4). A clamping groove adapted to the optical fiber (2) is arranged on the pressing plate (41).

3. The tunnel safety early warning device based on distributed optical fiber sensing according to claim 2, characterized in that: A rubber pad (43) is arranged in the clamping groove.

4. The tunnel safety early warning device based on distributed optical fiber sensing according to claim 1, characterized in that: The pressing block (52) is movably arranged on the detection plate (5) and is located on the side of the detection plate (5) away from the detection probe (6). The pressing block (52) is connected to the detection plate (5) through a connection spring (53). A limiting sleeve (44) is fixedly arranged on the detection frame (4). The pressing block (52) slidably penetrates through the limiting sleeve (44). A first limiting plate (522) and a second limiting plate (523) are fixedly arranged on the pressing block (52). The first limiting plate (522) and the second limiting plate (523) are respectively arranged on both sides of the limiting sleeve (44).

5. The tunnel safety early warning device based on distributed optical fiber sensing according to claim 4, characterized in that: The detection probe (6) includes a detection section (61) and a sensing section (62). The detection section (61) is used for penetrating into the tunnel wall. The sensing section (62) is slidably arranged on the detection section (61) along the length direction of the detection section (61). A limiting component for preventing the sensing section (62) from sliding is arranged on the detection section (61).

6. The tunnel safety warning device based on distributed optical fiber sensing according to claim 5, characterized in that: A first elastic member (612) for driving the sensing section (62) to slide away from the detection section (61) is arranged on the detection section (61).

7. The tunnel safety early warning device based on distributed optical fiber sensing according to claim 6, characterized in that: The limiting component includes a top cylinder (613), a limiting block (621) and a locking nut (614). The top cylinder (613) is slidably sleeved on the detection section (61). The limiting block (621) is fixedly arranged on the side wall of the sensing section (62), and the top cylinder (613) is used for abutting against the limiting block (621). The side wall of the detection section (61) is provided with an external thread. The locking nut (614) is sleeved on the detection section (61) and is in threaded cooperation with the detection section (61). The locking nut (614) is arranged on the side of the top cylinder (613) away from the limiting block (621).

8. The tunnel safety early warning device based on distributed optical fiber sensing according to claim 7, characterized in that: Two limiting strips (54) are fixedly arranged on the outer side wall of the detection board (5). Both of the two limiting strips (54) extend along the board surface of the detection board (5), and the two limiting strips (54) are arranged at intervals. The sensing section (62) of the detection probe (6) is arranged in the gap between the two limiting strips (54).

9. The tunnel safety early warning device based on distributed optical fiber sensing according to claim 8, characterized in that: Buffer plates (55) are slidably arranged on the sides of the two limiting strips (54) close to each other. The two buffer plates (55) are respectively arranged on both sides of the sensing section (62). A second elastic member (56) is arranged between the limiting strip (54) and the corresponding buffer plate (55). The second elastic member (56) is used to drive the buffer plate (55) to tightly press against the sensing section (62).

10. A working method of the tunnel safety early warning device based on distributed optical fiber sensing according to claim 8, characterized in that, Including the following steps: S1. When deformation occurs at a certain area position in the tunnel, the detection probe (6) at this position undergoes displacement; S2. The longitudinal strain is directly transmitted to the detection board (5) through the detection probe (6), and the detection board (5) is driven to move, driving the pressing block (52) to move through the connecting spring (53). The lateral strain drives the detection board (5) to move through the limiting strips (54) on both sides of the detection probe (6), and then drives the pressing block (52) to move through the connecting spring (53); S3. As the pressing block (52) moves, the signal is transmitted to the optical fiber (2) through the sensor (21), resulting in a change in the vibration frequency of the Rayleigh backscattered wave generated by the glass lattice of the optical fiber (2) at this position. By measuring this frequency change, the strain received by the optical fiber (2) can be deduced and fed back to the cloud server (1) in a timely manner, and based on this, the strain distribution of the tunnel can be inferred to achieve precise detection of strains occurring at different positions in the tunnel; S4. When the frequency change condition at a certain position of the optical fiber (2) exceeds a predetermined value, the cloud server (1) is used to control the alarm device (3) to give a safety warning.

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