Shield tunnel structure monitoring system and method

Abstract

The present invention relates to a shield tunnel structure monitoring system, comprising at least one of a settlement monitoring module, a horizontal displacement monitoring module, a regional crack monitoring module, and a convergence monitoring module, wherein the settlement monitoring module is used to monitor the settlement of the shield segment ring, the horizontal displacement monitoring module is used to monitor the horizontal displacement of the shield segment ring, the regional crack monitoring module is used to monitor the cracks between the segments of the shield tunnel, and the convergence monitoring module is used to monitor the diameter clearance convergence of the shield segment ring. Correspondingly, a shield tunnel structure monitoring method is also provided. The shield tunnel structure monitoring system and method provided by the present invention can monitor the structural condition of the shield tunnel in real time, including at least one of the following conditions: segment settlement, horizontal displacement, cracks between segments, and clearance convergence, thereby improving the service safety of the shield tunnel and facilitating the inspection and maintenance of the shield tunnel by the engineering department.

Description

Technical Field

[0001] The present invention belongs to the technical field of tunnel safety, and in particular relates to a shield tunnel structure monitoring system and a shield tunnel structure monitoring method based on the shield tunnel structure monitoring system. Background Art

[0002] Currently, during shield tunnel operation, most monitoring focuses solely on longitudinal settlement, lacking comprehensive structural monitoring. This makes it difficult to timely and comprehensively assess the structural safety status of shield tunnels. Furthermore, monitoring, early warning, and response are often separated, resulting in a lack of timely and accurate feedback on detected risk sources on-site, and a lack of a robust coordinated response mechanism. Furthermore, longitudinal settlement monitoring in shield tunnels often relies on manual monitoring using precision levels and total stations, or unmanned automatic measurement using static leveling systems. Common monitoring sensors are primarily point-type sensors, such as resistive, steel-string, and inductive sensors. These sensors generally suffer from difficulties in deployment, poor anti-interference and corrosion resistance, susceptibility to damage, and data distortion, making them inadequate for monitoring modern subway tunnel construction. Summary of the Invention

[0003] The present invention relates to a shield tunnel structure monitoring system and a shield tunnel structure monitoring method based on the shield tunnel structure monitoring system, which can at least solve some defects of the prior art.

[0004] The present invention relates to a shield tunnel structure monitoring system, comprising at least one of a settlement monitoring module, a horizontal displacement monitoring module, a regional crack monitoring module, and a convergence monitoring module, wherein the settlement monitoring module is used to monitor the settlement of a shield segment ring, the horizontal displacement monitoring module is used to monitor the horizontal displacement of a shield segment ring, the regional crack monitoring module is used to monitor cracks between segments of a shield tunnel, and the convergence monitoring module is used to monitor the diameter clearance convergence of a shield segment ring.

[0005] As one of the implementation modes, the settlement monitoring module and / or the horizontal displacement monitoring module adopts a displacement monitoring module, and the displacement monitoring module includes two displacement monitoring optical cables, and the displacement monitoring optical cables are fiber grating array strain cables integrated with multiple fiber grating strain sensors; the displacement monitoring optical cables are laid along the wall of the shield tunnel, and the two displacement monitoring optical cables are both distributed in a waveform in the longitudinal direction of the tunnel, and the waveforms of the two displacement monitoring optical cables are in anti-phase.

[0006] As one of the implementation methods, the crests and troughs of each displacement monitoring optical cable are sequentially distributed on each segment ring of the shield tunnel along the longitudinal direction of the tunnel, and are respectively fixed to the shield tunnel wall through fixing devices.

[0007] As one of the implementation methods, the displacement monitoring optical cable is distributed in a sawtooth waveform.

[0008] As one of the implementation methods, the regional crack monitoring module includes at least one crack monitoring optical cable, which is a fiber grating array strain cable integrated with multiple fiber grating strain sensors; the crack monitoring optical cable is laid out in a straight line along the longitudinal direction of the tunnel on the wall of the shield tunnel.

[0009] As one of the implementation methods, the convergence monitoring module includes at least one convergence monitoring optical cable, which is a fiber grating array strain cable integrated with multiple fiber grating strain sensors; the convergence monitoring optical cable is arranged in a ring along the circumference of the tunnel on the wall of the shield tunnel.

[0010] As one of the implementation methods, each monitoring module uses a fiber grating array cable for monitoring, and each fiber grating array cable is connected to a fiber grating data demodulator, which is used to receive the strain information sent by each fiber grating array cable, and demodulate it into a demodulation signal and send it to the background processor.

[0011] As one of the implementation modes, the shield tunnel structure monitoring system further includes a program-controlled alarm terminal, which is connected to the background processor via a cable or wirelessly connected to the background processor via a wireless transmission module.

[0012] The present invention also relates to a shield tunnel structure monitoring method based on the above-mentioned shield tunnel structure monitoring system, comprising:

[0013] The shield tunnel structure monitoring system is used to monitor the structural condition of the shield tunnel in real time, specifically including at least one of the following monitoring means: the settlement of the shield segment ring is monitored in real time by the settlement monitoring module, the horizontal displacement of the shield segment ring is monitored in real time by the horizontal displacement monitoring module, the cracks between the segments of the shield tunnel are monitored in real time by the regional crack monitoring module, and the diameter clearance convergence of the shield segment ring is monitored in real time by the convergence monitoring module;

[0014] The monitoring situation is fed back to the background processor; the background processor analyzes and determines the structural health status of the shield tunnel to guide the engineering department to carry out timely inspection and maintenance of the shield tunnel.

[0015] The present invention has at least the following beneficial effects: the shield tunnel structure monitoring system and method provided by the present invention can monitor the structural condition of the shield tunnel in real time, including at least one of the following conditions: segment settlement, horizontal displacement, cracks between segments, and clearance convergence, thereby improving the service safety of the shield tunnel and facilitating the inspection and maintenance of the shield tunnel by the engineering department. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0017] Figure 1 A schematic diagram of the layout of a shield tunnel structure monitoring system provided by an embodiment of the present invention;

[0018] Figure 2 A control schematic diagram of a shield tunnel structure monitoring system provided by an embodiment of the present invention;

[0019] Figure 3 A schematic diagram of the arrangement of a displacement monitoring module provided in an embodiment of the present invention;

[0020] Figure 4-Figure 7 Schematic diagram of several monitoring states of the displacement monitoring module;

[0021] Figure 8 A schematic structural diagram of a fixing device provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0022] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0023] Example 1

[0024] like Figure 1 An embodiment of the present invention provides a shield tunnel structure monitoring system, including at least one of a settlement monitoring module 2, a horizontal displacement monitoring module 3, a regional crack monitoring module 5 and a convergence monitoring module 4, wherein the settlement monitoring module 2 is used to monitor the settlement of the shield segment ring 11, the horizontal displacement monitoring module 3 is used to monitor the horizontal displacement of the shield segment ring 11, the regional crack monitoring module 5 is used to monitor the cracks between the segments of the shield tunnel 1, and the convergence monitoring module 4 is used to monitor the diameter clearance convergence of the shield segment ring 11.

[0025] Accordingly, this embodiment further provides a shield tunnel structure monitoring method based on the above-mentioned shield tunnel structure monitoring system, including:

[0026] The shield tunnel structure monitoring system is used to monitor the structural condition of the shield tunnel 1 in real time, specifically including at least one of the following monitoring means: the settlement of the shield segment ring 11 is monitored in real time by the settlement monitoring module 2, the horizontal displacement of the shield segment ring 11 is monitored in real time by the horizontal displacement monitoring module 3, the cracks between the segments of the shield tunnel 1 are monitored in real time by the regional crack monitoring module 5, and the convergence of the diameter clearance of the shield segment ring 11 is monitored in real time by the convergence monitoring module 4;

[0027] The monitoring situation is fed back to the background processor 62 ; the background processor 62 analyzes and determines the structural health status of the shield tunnel 1 to guide the engineering department to perform timely inspection and maintenance on the shield tunnel 1 .

[0028] The shield tunnel structure monitoring system and method provided in this embodiment can monitor the structural condition of the shield tunnel 1 in real time, including at least one of the following conditions: segment settlement, horizontal displacement, cracks between segments, and clearance convergence. This can improve the service safety of the shield tunnel 1 and facilitate the inspection and maintenance of the shield tunnel 1 by the engineering department.

[0029] Among them, preferably, the settlement monitoring module 2, the horizontal displacement monitoring module 3, the regional crack monitoring module 5 and the convergence monitoring module 4 are configured at the same time to ensure the comprehensiveness of the shield tunnel structure health monitoring.

[0030] Furthermore, each monitoring module utilizes a fiber grating array (FBG) cable for monitoring. Each FBG array cable is connected to a fiber grating data demodulator 61, which receives strain information transmitted by each FBG array cable and demodulates it into a demodulated signal, which is then transmitted to a backend processor 62. The signal transmission lines for each FBG sensor 2011 in the FBG array cable are unified and highly consistent, improving the accuracy of monitoring results. Preferably, the settlement monitoring module 2, the horizontal displacement monitoring module 3, the regional crack monitoring module 5, and the convergence monitoring module 4 all utilize fiber grating array strain cables.

[0031] More preferably, Figure 2 The shield tunnel structure monitoring system further includes a program-controlled alarm terminal 64, which can be connected to the backend processor 62 via a cable or wirelessly via a wireless transmission module 63. After analyzing and processing the demodulated signal, the backend processor 62 determines whether to send an alarm instruction to the program-controlled alarm terminal 64. The program-controlled alarm terminal 64 is configured to issue an alarm upon receiving the alarm instruction information sent by the backend processor 62. The program-controlled alarm terminal 64 can be equipped with an alarm device such as an audible and visual alarm.

[0032] It can be seen that the shield tunnel structure monitoring system provided in this embodiment can realize the monitoring and early warning of the shield tunnel structure safety, facilitate the timely and accurate feedback of the monitored risk information, and facilitate the implementation of the disposal linkage mechanism.

[0033] Example 2

[0034] The embodiment of the present invention further optimizes the above-mentioned embodiment 1.

[0035] The settlement monitoring module 2 and / or the horizontal displacement monitoring module 2003 adopts the displacement monitoring module 200 .

[0036] like Figure 3 The displacement monitoring module 200 includes two displacement monitoring optical cables 201, which are fiber grating array strain cables integrated with multiple fiber grating strain sensors 2011; the displacement monitoring optical cables 201 are laid along the wall of the shield tunnel 1, and the two displacement monitoring optical cables 201 are both distributed in a wave shape in the longitudinal direction of the tunnel, and the waveforms of the two displacement monitoring optical cables 201 are in opposite phases.

[0037] When the above-mentioned displacement monitoring module 200 is used to monitor the settlement of the shield tunnel 1, the displacement monitoring module 200 can be set at the waist of the tunnel; when the above-mentioned displacement monitoring module 200 is used to monitor the horizontal displacement of the shield tunnel 1, the displacement monitoring module 200 can be set at the top and / or bottom of the shield tunnel 1.

[0038] The fiber grating array strain cable, a single optical cable integrating multiple fiber grating strain sensors 2011, is an existing product featuring a wide monitoring coverage area (capable of covering over 10 km, depending on requirements), high measurement accuracy, and close spacing between sensor elements (minimum spacing of 1 cm). Using this fiber grating array strain cable enables continuous monitoring of the entire shield tunnel 1. Furthermore, the signal transmission paths of each fiber grating strain sensor 2011 are unified and highly consistent, improving the accuracy of monitoring results.

[0039] The above-described monitoring system is generally also equipped with a fiber Bragg grating (FBG) data demodulator 61, which is used to receive strain information transmitted from the displacement monitoring optical cable 201 and demodulate it into a demodulated signal, which is then transmitted to the background processor 62. The fiber Bragg grating (FBG) data demodulator 61 is also an existing device; it can be electrically connected or communicated with the background processor 62, which is conventional technology.

[0040] In one embodiment, Figure 3The crests and troughs of each displacement monitoring optical cable 201 are sequentially distributed along the longitudinal direction of the tunnel on each segment ring 11 of the shield tunnel 1. The crests and troughs of the displacement monitoring optical cable 201 are respectively fixedly connected to the wall of the shield tunnel 1 via a fixing device 7. Any fixing device 7 capable of fixing the optical cable to the shield segment is applicable to this embodiment. For example, the fixing device 7 adopts a wire buckle, a wire clamp, etc., which are not listed here one by one. Further preferably, in each displacement monitoring optical cable 201, the cable segment between two adjacent fixing devices 7 is not fixedly connected to the tunnel wall, but is in a straight state. Accordingly, the displacement monitoring optical cable 201 is distributed in a sawtooth waveform. In this design, the cable segment between two adjacent fixing devices 7 can quickly and accurately respond to the position changes of the segment ring 11. The cable segment between two adjacent fixing devices 7 includes at least one fiber grating strain sensor 2011.

[0041] Preferably, if Figure 3 In the displacement monitoring module 200, the peak of one displacement monitoring optical cable 201 and the trough of the other displacement monitoring optical cable 201 are secured by the same securing device 7. This structure not only facilitates the routing of the two displacement monitoring optical cables 201, but more importantly, allows the two displacement monitoring optical cables 201 in the same displacement monitoring module 200 to be routed adjacent to each other, resulting in similar strain response ranges and response speeds, thereby improving the accuracy of displacement monitoring at corresponding locations.

[0042] Preferably, each displacement monitoring optical cable 201 is laid on the inner wall of the shield tunnel 1, which facilitates the layout and maintenance of the displacement monitoring optical cable 201 and avoids being easily affected by external soil when installed on the outer wall of the tunnel.

[0043] Furthermore, the embodiment of the present invention further optimizes the above-mentioned shield tunnel structure monitoring method, which includes:

[0044] The strain information is collected in real time through the displacement monitoring optical cable 201, and the strain information sent by the displacement monitoring optical cable 201 is received by the fiber optic Bragg grating data demodulator 61, and demodulated into a demodulation signal and sent to the background processor 62;

[0045] The background processor 62 determines the structural health status of the shield tunnel 1 based on the demodulated signal analysis, so as to guide the engineering department to perform timely inspection and maintenance on the shield tunnel 1 .

[0046] Further preferably, each segment ring 11 is numbered in sequence along the longitudinal direction of the tunnel, for example, from one end of the shield tunnel 1 to the other end, each segment ring 11 is numbered in sequence as ring No. 1, ring No. 2, ring No. 2... ring No. n...; among the two displacement monitoring optical cables 201 of each group of displacement monitoring modules 200, one displacement monitoring optical cable 201 is defined as a first displacement monitoring optical cable 201, and the other displacement monitoring optical cable 201 is defined as a second displacement monitoring optical cable 201, the peak of the first displacement monitoring optical cable 201 and the trough of the second displacement monitoring optical cable 201 are far away from each other, and the trough of the first displacement monitoring optical cable 201 and the peak of the second displacement monitoring optical cable 201 are close to each other (for example, the two share a fixing device 7); the segment ring 11 where the peaks of the first displacement monitoring optical cable 201 are located is used as the monitoring reference to judge the structural health status of the shield tunnel 1.

[0047] Furthermore, the method specifically includes:

[0048] The strain monitoring values ​​collected on both sides of the wave crest of the first displacement monitoring optical cable 201 are ε n-a and ε n-b , the strain monitoring values ​​on both sides of the trough of the second displacement monitoring optical cable 201 are ε n-c and ε n-d , where n is the number of the segment ring 11 where the wave crest of the first displacement monitoring optical cable 201 is located;

[0049] like Figure 4 , when ε n-a and ε n-b Increase, ε n-c and ε n-d When it decreases, it is judged that the nth tube ring 11 has a positive displacement, and the positive displacement is the direction of the crest protrusion of the first displacement monitoring optical cable 201; otherwise, it is judged that the nth tube ring 11 has a negative displacement; wherein, generally, ε n-a and ε n-b The increase in value is the same, ε n-c and ε n-d The reduction value is the same; the displacement of the nth segment ring 11 is k1Δε n-a , k1 is the calibration coefficient.

[0050] like Figure 5 , when ε n-b and ε (n+2)-a Decrease, ε n-d and ε (n+2)-c When it increases, it is judged that the n+1 segment ring 11 has a positive displacement; otherwise, it is judged that the n+1 segment ring 11 has a negative displacement; wherein, generally, ε n-b and ε (n+2)-a The same reduction value, ε n-d and ε (n+2)-cThe increase in the value is the same; the displacement of the segment ring 11 is k2Δε n-d , k2 is the calibration coefficient.

[0051] like Figure 6 , when ε n-a and ε (n+2)-c Increase, ε n-c and ε (n+2)-a When the nth and n+1th segment rings 11 decrease, it is judged that positive displacement occurs; otherwise, it is judged that negative displacement occurs. n-b and ε n-d unchanged, ε n-a and ε (n+2)-c The increase in value is the same, ε n-c and ε (n+2)-a The reduction value is the same; the displacement of the nth segment ring 11 is k3Δε n-a , k3 is the calibration coefficient. When the displacement of the nth segment ring 11 and the n+1th segment ring 11 are different, ε n-a and ε (n+2)-c The added value will be different, ε n-c and ε (n+2)-a The reduction value of ε will also be different. n-b There will be a certain degree of increase or decrease (depending on whether the nth segment ring 11 has positive or negative displacement), but the increase is less than ε n-a / The reduction is less than ε n-c , ε n-d There will be a certain degree of increase or decrease, but the increase is less than ε n-a / The reduction is less than ε n-c On this basis, through ε n-a～ ε n-d , ε (n+2)-a , ε (n+2)-c The increase or decrease of etc. can accurately determine the displacement difference between the nth segment ring 11 and the n+1th segment ring 11.

[0052] Similarly, when ε n-b and ε (n-2)-d Increase, ε n-d and ε (n-2)-b When the nth and n-1th segment rings 11 decrease, it is judged that the nth and n-1th segment rings 11 have positive displacement; otherwise, it is judged that the two have negative displacement. n-a and ε n-c unchanged, ε n-b and ε (n-2)-d The increase in value is the same, ε n-d and ε (n-2)-bThe reduction value is the same; when the displacement of the nth segment ring 11 and the n-1th segment ring 11 are different, ε n-b and ε (n-2)-d The added value will be different, ε n-d and ε (n-2)-b The reduction value of ε will also be different. n-a There will be a certain degree of increase or decrease (depending on whether the nth segment ring 11 has positive or negative displacement), but the increase is less than ε n-b / The reduction is less than ε n-d , ε n-c There will be a certain degree of increase or decrease, but the increase is less than ε n-b / The reduction is less than ε n-d On this basis, through ε n-a～ ε n-d , ε (n-2)-b , ε (n-2)-d The increase or decrease of etc. can accurately determine the displacement difference between the nth segment ring 11 and the n-1th segment ring 11.

[0053] like Figure 7 , when ε n-a , ε n-b and ε (n+2)-a Both increase and ε n-b The value added is the largest, and ε n-c and ε (n+2)-c When the displacement decreases, it is determined that the segment ring n 11 and the segment ring n+1 11 are displaced, and the segment ring n 11 is positively displaced and the segment ring n+1 11 is negatively displaced. Conversely, it is determined that the segment ring n 11 and the segment ring n+1 11 are displaced, and the segment ring n 11 is negatively displaced and the segment ring n+1 11 is positively displaced. The displacement of the segment ring n 11 is k4ε n-b , k4 is the calibration coefficient. ε n-d There may be many variations. For example, when the nth segment ring 11 is displaced before the n+1th segment ring 11 or the nth segment ring 11 is displaced after the n+1th segment ring 11, ε n-d Generally, it will decrease first and then increase. When the segment ring n and the segment ring n+1 11 are displaced synchronously, ε n-d Generally, it will show a decreasing trend. In addition, when the displacement speeds of the nth segment ring 11 and the n+1th segment ring 11 are different, different strain changes will also appear. It can be seen that on this basis, through ε n-a～ ε n-d , ε (n+2)-a , ε (n+2)-c The increase or decrease of etc. can accurately determine the displacement difference between the nth segment ring 11 and the n-1th segment ring 11.

[0054] Similarly, when ε n-a , ε n-b and ε (n-2)-b Both increase and ε n-a The value added is the largest, and ε n-d and ε (n-2)-d When the displacement decreases, it is determined that the segment ring n 11 and the segment ring n-1 11 are dislocated, and the segment ring n 11 is positively displaced and the segment ring n-1 11 is negatively displaced; otherwise, it is determined that the segment ring n 11 and the segment ring n-1 11 are dislocated, and the segment ring n 11 is negatively displaced and the segment ring n-1 11 is positively displaced. n-c There may be many changes, which will not be analyzed one by one here.

[0055] It can be seen that in this embodiment, reliable monitoring of the displacement of a single segment ring 11, the displacement of multiple segment rings 11, and the misaligned displacement of adjacent segment rings 11 can be achieved. The above algorithm can calculate the data monitored by the displacement monitoring optical cable 201 and ultimately invert the multi-directional displacement of the shield tunnel 1, which has significant advantages such as strong applicability and simple operation.

[0056] Example 3

[0057] The embodiment of the present invention further optimizes the above-mentioned embodiment 1 or embodiment 2.

[0058] The regional crack monitoring module 5 includes at least one crack monitoring optical cable, which is a fiber grating array strain gauge cable integrated with multiple fiber grating strain sensors. The crack monitoring optical cable is arranged in a straight line along the longitudinal direction of the tunnel on the wall of the shield tunnel 1. If multiple crack monitoring optical cables are provided, they are preferably arranged sequentially and spaced apart along the circumference of the tunnel.

[0059] The crack monitoring optical cable can be laid only in key areas or continuously along the entire length of the shield tunnel 1. The crack monitoring optical cable is preferably laid on the inner wall of the shield tunnel 1, which is convenient for laying and repairing the crack monitoring optical cable and can avoid being easily affected by external soil when installed on the outer wall of the tunnel. Figure 1The above-mentioned crack monitoring optical cable is fixedly connected to the pipe wall of the shield tunnel 1 through multiple optical cable installation units; optical cable installation units that can fix the optical cable on the shield pipe segment are all suitable for this embodiment, for example, the optical cable installation unit adopts wire buckles, wire clamps, etc., which are not listed here one by one; each optical cable installation unit is preferably distributed on each shield pipe segment ring 11 in sequence along the longitudinal direction of the tunnel, and further preferably, in each crack monitoring optical cable, the cable section between two adjacent optical cable installation units is not fixedly connected to the tunnel pipe wall, but is in a straight state, which can quickly and accurately sense the occurrence of cracks in the pipe segment ring 11; in this design, the cable section between two adjacent optical cable installation units includes at least one fiber grating strain sensor.

[0060] In one embodiment, the convergence monitoring module 4 includes at least one convergence monitoring optical cable, which is a fiber Bragg grating array strain cable integrated with multiple fiber Bragg grating strain sensors. The convergence monitoring optical cable is annularly arranged along the circumference of the tunnel on the wall of the shield tunnel 1. When multiple convergence monitoring optical cables are provided, they are preferably arranged sequentially and spaced apart longitudinally along the tunnel.

[0061] The convergence monitoring optical cable is preferably installed on the inner wall of the shield tunnel 1 to facilitate its installation and maintenance, and to avoid being easily affected by external soil when installed on the outer wall of the tunnel. The convergence monitoring optical cable is preferably attached to the tunnel wall. The convergence monitoring optical cable can be bonded to the tunnel wall or fixed in other ways. Alternatively, a monitoring groove can be provided in the tunnel wall, the convergence monitoring optical cable can be buried in the groove, and then cemented with concrete.

[0062] Example 4

[0063] This embodiment provides an internally fixed fiber Bragg grating protection device, which can be used in the above embodiments to arrange the monitoring optical cable on the tunnel wall, for example, as the fixing device 7 therein.

[0064] like Figure 8 The protection device includes a protection shell, which is provided with a fiber Bragg grating inlet and a fiber Bragg grating outlet. A protection beam 73 is provided inside the protection shell. The protection beam 73 is an annular beam suitable for enclosing the sensor 2011 in the fiber Bragg grating 201 and is provided with a fiber Bragg grating entry hole and a fiber Bragg grating exit hole.

[0065] In one embodiment, the protective housing includes a base plate 71 and a cover plate 72. The protective beam 73 is mounted on the base plate 71. The cover plate 72 is removably attached to the base plate 71. The fiber Bragg grating 201 to be protected can be enclosed in the housing formed by the cover plate 72 and the base plate 71, providing better protection. Optionally, the fiber Bragg grating inlet and the fiber Bragg grating outlet are both located on the base plate 71.

[0066] For the detachable connection between the base plate 71 and the cover plate 72, threaded fasteners such as screws can be used for connection; of course, snap-on connection and other methods are also feasible solutions.

[0067] Preferably, a mounting portion is provided on the base plate 71 to facilitate installation at a monitoring point. The mounting portion may be a mounting hole or the like.

[0068] When in use, the fiber Bragg grating 201 passes through the above-mentioned fiber Bragg grating inlet, fiber Bragg grating entry hole, fiber Bragg grating exit hole and fiber Bragg grating exit in sequence. Preferably, the fiber Bragg grating inlet, the fiber Bragg grating exit, the fiber Bragg grating entry hole and the fiber Bragg grating exit hole are coaxially arranged, so that the fiber Bragg grating 201 can pass straight through the above-mentioned protective device, thereby ensuring the accuracy and reliability of the monitoring results.

[0069] In one embodiment, the protective beam 73 is an elastic beam. When encountering strong tensile or compressive deformation, the protective beam 73 is first subjected to force. The elastic beam can better dissipate energy and reduce vibration, thereby providing better protection for the fiber Bragg grating 201.

[0070] In one embodiment, Figure 8 The protective beam 73 is a diamond-shaped beam. The diamond-shaped beam provides high structural stability and more reliable load-bearing performance, further enhancing the protective effect of the fiber Bragg grating 201. Furthermore, the fiber Bragg grating entry hole and the fiber Bragg grating exit hole are disposed oppositely at the two corners of the diamond-shaped beam.

[0071] Further optimize the above protection device, such as Figure 8 A spring sleeve 75 is coaxially connected to the entrance of the fiber Bragg grating. The spring sleeve 75 is used to connect to the external structure, and can effectively play a role in vibration reduction and buffering, thereby improving the protective effect of the protective shell. Moreover, the fiber Bragg grating 201 passes through the spring sleeve 75 into the protective shell, which can further enhance the protection of the fiber Bragg grating 201. Preferably, the spring sleeve 75 includes a sleeve body and a spring housed in the sleeve body. The sleeve body can constrain and protect the spring. The sleeve body can be made of a metal hose, a rubber hose, or other materials. The connection between the spring sleeve 75 and the protective shell includes, but is not limited to, threaded connection, bolt fixing, interference fit connection, welding, etc.

[0072] Further optimize the above protection device, such as Figure 8 An armored tube 16 is provided at the fiber Bragg grating outlet to enhance the protection of the fiber Bragg grating 201 and to perform fiber fusion splicing according to different monitoring objects, thereby achieving the purpose of monitoring multiple physical quantities required for real-time measurement engineering.

[0073] Preferably, the protective beam 73 can be detachably installed in the protective shell to facilitate installation and maintenance. Figure 8 The protective beam 73 is mounted on a mounting plate 74, which is removably fixed within the protective housing. For example, the mounting plate 74 is connected to the protective housing via a fixing pin. Based on this structure, the protective beam 73 is configured as a cantilever beam, eliminating direct connection between the protective beam 73 and the protective housing. This further extends the force transmission path and reduces the effects of deformation, load, vibration, etc. on the fiber Bragg grating 201. In other embodiments, the protective beam 73 can also be fixed to the base plate 71 by cooperating with the mounting plate 74 and a retaining structure. The retaining structure can, for example, employ multiple retaining pins.

[0074] The protective device provided in this embodiment fully surrounds and secures the fiber Bragg grating (FBG) 201, effectively protecting it and stabilizing its condition, thereby improving the accuracy and reliability of monitoring results. The protective device has a simple structure and is easy to install, making it well suited to engineering installation requirements.

[0075] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A shield tunnel structure monitoring system, characterized by: The system comprises at least one of a settlement monitoring module, a horizontal displacement monitoring module, a regional crack monitoring module, and a convergence monitoring module, wherein the settlement monitoring module is used to monitor the settlement of the shield segment ring, the horizontal displacement monitoring module is used to monitor the horizontal displacement of the shield segment ring, the regional crack monitoring module is used to monitor the cracks between the segments of the shield tunnel, and the convergence monitoring module is used to monitor the diameter clearance convergence of the shield segment ring; The settlement monitoring module and / or the horizontal displacement monitoring module adopts a displacement monitoring module, and the displacement monitoring module includes two displacement monitoring optical cables, which are fiber grating array strain cables integrated with multiple fiber grating strain sensors; the displacement monitoring optical cables are laid along the wall of the shield tunnel, and the two displacement monitoring optical cables are both distributed in a wave shape in the longitudinal direction of the tunnel, and the waveforms of the two displacement monitoring optical cables are in opposite phases; The crests and troughs of each displacement monitoring optical cable are sequentially distributed on each segment ring of the shield tunnel along the longitudinal direction of the tunnel, and are respectively fixed to the shield tunnel wall through fixing devices. The cable section between two adjacent fixing devices includes at least one fiber Bragg grating strain sensor. Each segment ring is numbered in sequence along the longitudinal direction of the tunnel; in each set of two displacement monitoring optical cables, the wave crests of the first displacement monitoring optical cable and the wave troughs of the second displacement monitoring optical cable are far away from each other; the segment ring where each wave crest of the first displacement monitoring optical cable is located is used as the monitoring reference; The displacement monitoring module is also equipped with a fiber Bragg grating (FBG) data demodulator and a background processor. The fiber Bragg grating (FBG) data demodulator is used to receive strain information sent by the displacement monitoring optical cable and demodulate it into a demodulated signal and send it to the background processor. The background processor is used to analyze the demodulated signal and determine the structural health status of the shield tunnel, so as to guide the engineering department to carry out timely inspection and maintenance of the shield tunnel. The background processor analyzes the demodulated signal to determine the structural health of the shield tunnel, guiding the engineering department to conduct timely inspection and maintenance of the shield tunnel. The specific details include: The strain monitoring values ​​collected on both sides of the wave crest of the first displacement monitoring optical cable are ε n-a and ε n-b , the strain monitoring values ​​on both sides of the trough of the second displacement monitoring cable are ε n-c and ε n-d , where n is the number of the segment ring where the wave crest of the first displacement monitoring optical cable is located; When ε n-a and ε n-b Increase, ε n-c and ε n-d When the displacement decreases, it is determined that the nth tube ring has a positive displacement, and the positive displacement is the direction in which the crest of the first displacement monitoring optical cable protrudes; otherwise, it is determined that the nth tube ring has a negative displacement; When ε n-b and ε (n+2)-a Decrease, ε n-d and ε (n+2)-c When it increases, it is judged that the n+1 segment ring has a positive displacement; otherwise, it is judged that the n+1 segment ring has a negative displacement; When ε n-a and ε (n+2)-c Increase, ε n-c and ε (n+2)-a When the pressure decreases, it is judged that the segment rings n and n+1 have positive displacement; otherwise, it is judged that the two have negative displacement; When ε n-b and ε (n-2)-d Increase, ε n-d and ε (n-2)-b When the pressure decreases, it is judged that the segment rings n and n-1 have positive displacement; otherwise, it is judged that the two have negative displacement; When ε n-a , ε n-b and ε (n+2)-a Both increase and ε n-b The value added is the largest, and ε n-c and ε (n+2)-c When the value decreases, it is determined that the segment ring n and the segment ring n+1 are dislocated, and the segment ring n is displaced in a positive direction; otherwise, it is determined that the segment ring n and the segment ring n+1 are dislocated, and the segment ring n is displaced in a negative direction. When ε n-a , ε n-b and ε (n-2)-b Both increase and ε n-a The value added is the largest, and ε n-d and ε (n-2)-d When it decreases, it is judged that the nth segment ring and the n-1th segment ring are dislocated, and the nth segment ring undergoes positive displacement; otherwise, it is judged that the nth segment ring and the n-1th segment ring are dislocated, and the nth segment ring undergoes negative displacement.

2. The shield tunnel structure monitoring system according to claim 1, characterized in that: The displacement monitoring optical cable is distributed in a sawtooth waveform.

3. The shield tunnel structure monitoring system according to claim 1, wherein: The regional crack monitoring module includes at least one crack monitoring optical cable, which is a fiber grating array strain cable integrated with multiple fiber grating strain sensors; the crack monitoring optical cable is laid on the wall of the shield tunnel in a straight line along the longitudinal direction of the tunnel.

4. The shield tunnel structure monitoring system according to claim 1, wherein: The convergence monitoring module includes at least one convergence monitoring optical cable, which is a fiber grating array strain cable integrated with multiple fiber grating strain sensors; the convergence monitoring optical cable is annularly arranged on the wall of the shield tunnel along the circumference of the tunnel.

5. The shield tunnel structure monitoring system according to any one of claims 1 to 4, characterized in that: Each monitoring module uses a fiber grating array cable for monitoring, and each fiber grating array cable is connected to a fiber grating data demodulator, which is used to receive the strain information sent by each fiber grating array cable and demodulate it into a demodulation signal and send it to the background processor.

6. The shield tunnel structure monitoring system according to claim 5, characterized in that: It also includes a program-controlled alarm terminal, which is connected to the background processor via a cable or wirelessly connected to the background processor via a wireless transmission module.

7. A shield tunnel structure monitoring method based on the shield tunnel structure monitoring system according to any one of claims 1 to 6, characterized in that: include, The shield tunnel structure monitoring system is used to monitor the structural condition of the shield tunnel in real time, specifically including at least one of the following monitoring means: the settlement of the shield segment ring is monitored in real time by the settlement monitoring module, the horizontal displacement of the shield segment ring is monitored in real time by the horizontal displacement monitoring module, the cracks between the segments of the shield tunnel are monitored in real time by the regional crack monitoring module, and the diameter clearance convergence of the shield segment ring is monitored in real time by the convergence monitoring module; The monitoring situation is fed back to the background processor; the background processor analyzes and determines the structural health status of the shield tunnel to guide the engineering department to carry out timely inspection and maintenance of the shield tunnel.

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