CN114894102B - Shield tunnel structure monitoring system and method based on array grating - Google Patents
Shield tunnel structure monitoring system and method based on array grating Download PDFInfo
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Classifications
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B11/00—Measuring arrangements characterised by the use of optical techniques
- G01B11/02—Measuring arrangements characterised by the use of optical techniques for measuring length, width or thickness
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B11/00—Measuring arrangements characterised by the use of optical techniques
- G01B11/16—Measuring arrangements characterised by the use of optical techniques for measuring the deformation in a solid, e.g. optical strain gauge
- G01B11/165—Measuring arrangements characterised by the use of optical techniques for measuring the deformation in a solid, e.g. optical strain gauge by means of a grating deformed by the object
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01C—MEASURING DISTANCES, LEVELS OR BEARINGS; SURVEYING; NAVIGATION; GYROSCOPIC INSTRUMENTS; PHOTOGRAMMETRY OR VIDEOGRAMMETRY
- G01C5/00—Measuring height; Measuring distances transverse to line of sight; Levelling between separated points; Surveyors' levels
Abstract
The invention relates to a shield tunnel structure monitoring system and method based on an array grating, wherein the system comprises at least one group of displacement monitoring modules, each displacement monitoring module comprises two displacement monitoring optical cables, and each displacement monitoring optical cable is a fiber grating array strain cable integrated with a plurality of fiber grating strain sensors; the displacement monitoring optical cables are laid along the pipe wall of the shield tunnel, the two displacement monitoring optical cables are distributed in a waveform manner in the longitudinal direction of the tunnel, and the waveforms of the two displacement monitoring optical cables are reversed. Through the special layout of displacement monitoring optical cable, can realize the reliable monitoring to the condition such as single section of jurisdiction ring displacement, a plurality of section of jurisdiction ring displacement and adjacent section of jurisdiction ring dislocation displacement, can calculate the data that displacement monitoring optical cable monitored and finally reverse the diversified displacement condition that is the shield constructs the tunnel, have strong applicability, easy and simple to handle etc. show advantage.
Description
Technical Field
The invention belongs to the technical field of tunnel safety, and particularly relates to a shield tunnel structure monitoring system and method based on an array grating.
Background
Currently, the vertical settlement monitoring of a shield tunnel mostly adopts manual monitoring of a precise level gauge and a total station or unmanned automatic measurement of a static leveling system. The common monitoring sensor is mainly a resistive, steel string type, inductive and other point type sensor, and the sensor has the defects of difficult layout, poor anti-interference capability, poor corrosion resistance, easy destruction, easy data distortion and the like, and cannot meet the requirements of modern subway tunnel construction monitoring.
Disclosure of Invention
The invention relates to a shield tunnel structure monitoring system and method based on an array grating, which at least can solve part of defects in the prior art.
The invention relates to a shield tunnel structure monitoring system based on an array grating, which comprises at least one group of displacement monitoring modules, wherein each displacement monitoring module comprises two displacement monitoring optical cables, and each displacement monitoring optical cable is a fiber grating array strain cable integrated with a plurality of fiber grating strain sensors; the displacement monitoring optical cables are laid along the pipe wall of the shield tunnel, the two displacement monitoring optical cables are distributed in a waveform manner in the longitudinal direction of the tunnel, and the waveforms of the two displacement monitoring optical cables are reversed.
As one of implementation modes, the wave crest and the wave trough 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 fixedly connected with the pipe wall of the shield tunnel through fixing devices respectively.
As one embodiment, the displacement monitoring optical cable is distributed in a sawtooth waveform.
In one embodiment, in the displacement monitoring module, the peak of one of the displacement monitoring optical cables and the trough of the other one of the displacement monitoring optical cables are fixed by the same fixing device.
As one of the embodiments, each displacement monitoring optical cable is laid on the inner pipe wall of the shield tunnel.
As one of the implementation modes, the displacement monitoring modules comprise a plurality of groups, and comprise a settlement monitoring module and a horizontal displacement monitoring module, wherein the settlement monitoring module is arranged at the waist of the tunnel, and the horizontal displacement monitoring module is arranged at the top or the bottom of the tunnel.
The invention also relates to a shield tunnel structure monitoring method based on the shield tunnel structure monitoring system, which comprises the following steps:
strain information is acquired in real time through the displacement monitoring optical cable, the strain information sent by the displacement monitoring optical cable is received through a fiber bragg grating data demodulator, demodulated into a demodulation signal and sent to a background processor;
and the background processor analyzes and judges the structural health condition of the shield tunnel according to the demodulation signals so as to guide a working department to timely detect and maintain the shield tunnel.
As one of the implementation modes, the wave crest and the wave trough of each displacement monitoring optical cable are sequentially distributed on each segment ring along the longitudinal direction of the tunnel and are fixedly connected with the pipe wall of the shield tunnel through fixing devices respectively; sequentially numbering all segment rings along the longitudinal direction of the tunnel; in the two displacement monitoring optical cables of each group of displacement monitoring modules, the wave crest of the first displacement monitoring optical cable and the wave trough of the second displacement monitoring optical cable are far away from each other; and judging the structural health condition of the shield tunnel by taking the segment ring of each wave crest of the first displacement monitoring optical cable as a monitoring reference.
As one embodiment, the method specifically includes:
collecting strain monitoring values of two adjacent sides of a wave crest of a first displacement monitoring optical cable as epsilon respectively n-a And epsilon n-b Strain monitoring values of two adjacent sides of the trough of the second displacement monitoring optical cable are epsilon respectively n-c And epsilon n-d Wherein n is the number of the segment ring where the wave crest of the first displacement monitoring optical cable is located;
when epsilon n-a And epsilon n-b Increase, epsilon n-c And epsilon n-d When the number n segment ring is reduced, judging that the number n segment ring is subjected to forward displacement, wherein the forward displacement is the crest convex direction of the first displacement monitoring optical cable; otherwise, judging that the n-number segment ring is subjected to negative displacement;
when epsilon n-b And epsilon (n+2)-a Reduction, epsilon n-d And epsilon (n+2)-c When the number n+1 segment ring is increased, judging that the number n+1 segment ring is positively displaced; otherwise, judging that the n+1 segment ring is subjected to negative displacement;
when epsilon n-a And epsilon (n+2)-c Increase, epsilon n-c And epsilon (n+2)-a When the number n and the number n+1 segment rings are reduced, judging that the number n segment rings are positively displaced; otherwise, judging that the two are in negative displacement;
when epsilon n-b And epsilon (n-2)-d Increase, epsilon n-d And epsilon (n-2)-b When the number n and the number n-1 segment rings are reduced, judging that the number n and the number n-1 segment rings are positively displaced; otherwise, judging that the two are in negative displacement;
when epsilon n-a 、ε n-b And epsilon (n+2)-a All increase and epsilon n-b Is the largest in increment and epsilon n-c And epsilon (n+2)-c When the displacement is reduced, the dislocation displacement of the n-number segment ring and the n+1-number segment ring is judged, and the n-number segment ring is positively displaced; otherwise, judging that the n-number segment ring and the n+1-number segment ring are displaced in a dislocation manner, and enabling the n-number segment ring to be displaced in a negative direction;
when epsilon n-a 、ε n-b And epsilon (n-2)-b All increase and epsilon n-a Is increased by (a)Maximum value, and epsilon n-d And epsilon (n-2)-d When the displacement is reduced, the dislocation displacement of the n-number segment ring and the n-1 number segment ring is judged, and the n-number segment ring is positively displaced; and otherwise, judging that the n-number segment ring and the n-1-number segment ring are displaced in a dislocation manner, and enabling the n-number segment ring to be displaced in a negative direction.
The invention has at least the following beneficial effects:
in the invention, the displacement monitoring optical cable adopts the fiber bragg grating array strain cable, and the signal transmission line of the fiber bragg grating strain sensor is uniform and high in consistency, so that the accuracy of the monitoring result can be improved.
Through the special layout of displacement monitoring optical cable, can realize the reliable monitoring to the condition such as single section of jurisdiction ring displacement, a plurality of section of jurisdiction ring displacement and adjacent section of jurisdiction ring dislocation displacement, can calculate the data that displacement monitoring optical cable monitored and finally reverse the diversified displacement condition that is the shield constructs the tunnel, have strong applicability, easy and simple to handle etc. show advantage.
Drawings
In order to more clearly illustrate the embodiments of the invention or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described, it being obvious that the drawings in the following description are only some embodiments of the invention, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
Fig. 1 is a schematic layout diagram of a displacement monitoring module according to an embodiment of the present invention;
FIGS. 2-5 are schematic diagrams of several monitoring states of the displacement monitoring module;
fig. 6 is a schematic layout diagram of a shield tunnel structure monitoring system according to an embodiment of the present invention;
fig. 7 is a control schematic diagram of a shield tunnel structure monitoring system according to an embodiment of the present invention;
fig. 8 is a schematic structural diagram of a fixing device according to an embodiment of the present invention.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and completely, and it is apparent that the described embodiments are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
Example 1
Referring to fig. 1, an embodiment of the present invention provides a shield tunnel structure monitoring system based on an array grating, which includes at least one group of displacement monitoring modules 200, where the displacement monitoring modules 200 include two displacement monitoring optical cables 201, and the displacement monitoring optical cables 201 are fiber grating array strain cables integrated with a plurality of fiber grating strain sensors; the displacement monitoring optical cables 201 are laid along the pipe wall of the shield tunnel 1, the two displacement monitoring optical cables 201 are distributed in a waveform manner in the longitudinal direction of the tunnel, and the waveforms of the two displacement monitoring optical cables 201 are reversed.
The displacement monitoring module 200 can be used for monitoring the settlement of the shield tunnel 1, and the displacement monitoring module 200 can be arranged at the waist of the tunnel based on the requirement; the displacement monitoring module 200 may also be used to monitor the horizontal displacement of the shield tunnel 1, and based on this requirement, the displacement monitoring module 200 may be disposed at the top and/or bottom of the shield tunnel 1. Preferably, the displacement monitoring modules 200 have a plurality of groups, including a settlement monitoring module 2 and a horizontal displacement monitoring module 3200, wherein the settlement monitoring module 2 is arranged at the waist of the tunnel, and the horizontal displacement monitoring module 3200 is arranged at the top or bottom of the tunnel.
The fiber grating array strain cable is a cable with a plurality of fiber grating strain sensors integrated in a single optical cable, is an existing product, and has the characteristics of wide monitoring coverage (more than 10km can be covered according to the requirement), high measurement precision, small spacing of sensing units (the minimum spacing can be 1 cm) and the like. The adoption of the fiber bragg grating array strain cable can realize the full-line continuous monitoring of the shield tunnel 1, and the signal transmission lines of the fiber bragg grating strain sensors are unified and high in consistency, so that the accuracy of monitoring results can be improved.
For the above monitoring system, a fiber grating data demodulator 61 is generally configured to receive the strain information sent by the displacement monitoring optical cable 201, demodulate the strain information into a demodulated signal, and send the demodulated signal to the background processor 62. The fiber bragg grating data demodulator 61 is also an existing device; which may be in electrical or communicative connection with the background processor 62, as is conventional.
In one embodiment, as shown in fig. 1, the wave crest and the wave trough of each displacement monitoring optical cable 201 are sequentially distributed on each segment ring 11 of the shield tunnel 1 along the longitudinal direction of the tunnel, and the wave crest and the wave trough of each displacement monitoring optical cable 201 are respectively fixedly connected with the pipe wall of the shield tunnel 1 through a fixing device 7. The fixing device 7 capable of fixing the optical cable to the shield segment is applicable to this embodiment, and for example, the fixing device 7 is a wire buckle, a wire clip, or the like, which is not exemplified herein. Further preferably, in each displacement monitoring optical cable 201, the cable segment between two adjacent fixing devices 7 is not fixedly connected with the wall of the tunnel, but is in a straightened state, and correspondingly, the displacement monitoring optical cables 201 are distributed in a sawtooth waveform; in this design, the cable segment between two adjacent fixtures 7 can quickly and accurately respond to the change in position of the segment ring 11; at least one fiber grating strain sensor is included in the cable segment between two adjacent fixtures 7.
Preferably, as shown in fig. 1, 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 fixed by the same fixing device 7. In this structure, the two displacement monitoring optical cables 201 are conveniently laid, more importantly, the two displacement monitoring optical cables 201 in the same displacement monitoring module 200 are adjacently laid, the strain response range and the response speed of the two displacement monitoring optical cables are close, and the accuracy of displacement monitoring at the corresponding positions can be improved.
Preferably, each displacement monitoring optical cable 201 is laid on the inner pipe wall of the shield tunnel 1, so that the displacement monitoring optical cables 201 are convenient to lay and overhaul, and the influence of external soil bodies and the like when being installed on the outer wall of the tunnel can be avoided.
Further, the embodiment of the invention also relates to a shield tunnel structure monitoring method, which is realized based on the shield tunnel structure monitoring system, and concretely comprises the following steps:
strain information is acquired in real time through the displacement monitoring optical cable 201, the strain information sent by the displacement monitoring optical cable 201 is received through the fiber bragg grating data demodulator 61, demodulated into a demodulation signal and sent to the background processor 62;
the background processor 62 analyzes and judges the structural health condition of the shield tunnel 1 according to the demodulation signals so as to guide the working department to timely detect and maintain the shield tunnel 1.
Further preferably, each segment ring 11 is numbered sequentially in the tunnel longitudinal direction, for example, each segment ring 11 is numbered sequentially from one end to the other end of the shield tunnel 1 as a ring No. 1, a ring No. 2. In the two displacement monitoring optical cables 201 of each group of displacement monitoring modules 200, one of the displacement monitoring optical cables 201 is defined as a first displacement monitoring optical cable 201, the other displacement monitoring optical cable 201 is defined as a second displacement monitoring optical cable 201, the wave crest of the first displacement monitoring optical cable 201 and the wave trough of the second displacement monitoring optical cable 201 are far away from each other, and the wave trough of the first displacement monitoring optical cable 201 and the wave crest of the second displacement monitoring optical cable 201 are close to each other (for example, the two share one fixing device 7); and judging the structural health condition of the shield tunnel 1 by taking the segment ring 11 where each wave crest of the first displacement monitoring optical cable 201 is positioned as a monitoring reference.
Further, the method specifically comprises the following steps:
the strain monitoring values of the two adjacent sides of the peak of the first displacement monitoring optical cable 201 are respectively epsilon n-a And epsilon n-b Strain monitoring values of adjacent two sides of the trough of the second displacement monitoring optical cable 201 are respectively epsilon n-c And epsilon n-d Wherein n is the number of the segment ring 11 where the peak of the first displacement monitoring optical cable 201 is located;
when ε is as shown in FIG. 2 n-a And epsilon n-b Increase, epsilon n-c And epsilon n-d When the displacement is reduced, judging that the n-number segment ring 11 is positively displaced, wherein the positive displacement is the crest projecting direction of the first displacement monitoring optical cable 201; otherwise, judging that the n-number segment ring 11 is subjected to negative displacement; wherein generally epsilon n-a And epsilon n-b Added value of (2)Same as epsilon n-c And epsilon n-d The reduction value of (2) is the same; the displacement of the n-number segment ring 11 is k 1 Δε n-a ，k 1 Is the calibration coefficient.
When ε is as shown in FIG. 3 n-b And epsilon (n+2)-a Reduction, epsilon n-d And epsilon (n+2)-c When the number n+1 segment ring 11 is increased, judging that the positive displacement occurs; otherwise, judging that the n+1 segment ring 11 is subjected to negative displacement; wherein generally epsilon n-b And epsilon (n+2)-a Is the same, ε n-d And epsilon (n+2)-c The added value of (2) is the same; the displacement of the n-number segment ring 11 is k 2 Δε n-d ，k 2 Is the calibration coefficient.
When ε, as in FIG. 4 n-a And epsilon (n+2)-c Increase, epsilon n-c And epsilon (n+2)-a When the displacement is reduced, the segment ring 11 with the number n and the number n+1 is judged to be positively displaced; otherwise, judging that the two are in negative displacement. Wherein, epsilon when the n-number segment ring 11 and the n+1-number segment ring 11 synchronously displace n-b And epsilon n-d Unchanged epsilon n-a And epsilon (n+2)-c The increment value of epsilon is the same n-c And epsilon (n+2)-a The reduction value of (2) is the same; the displacement of the n-number segment ring 11 is k 3 Δε n-a ，k 3 Is the calibration coefficient. Epsilon when the displacement amounts of the n-number segment ring 11 and the n+1-number segment ring 11 are different n-a And epsilon (n+2)-c May be different in the added value of epsilon n-c And epsilon (n+2)-a There will be a difference in the decrease value of epsilon n-b To a certain extent (depending on whether the n segment ring 11 is positively or negatively displaced) but with an increase of less than epsilon n-a The reduction amplitude is less than epsilon n-c ，ε n-d To a certain extent but with an increase of less than epsilon n-a The reduction amplitude is less than epsilon n-c The method comprises the steps of carrying out a first treatment on the surface of the Based on this, pass epsilon n-a～ ε n-d 、ε (n+2)-a 、ε (n+2)-c The increase or decrease of the number n segment ring 11 and the number n+1 segment ring 11 can accurately determine the difference in displacement amount.
Similarly, when ε n-b And epsilon (n-2)-d Increase, epsilon n-d And epsilon (n-2)-b In the event of a decrease in the amount of time,judging that the n-number segment ring 11 is positively displaced; otherwise, judging that the two are in negative displacement. Wherein, epsilon when the n-number segment ring 11 and the n-1 number segment ring 11 synchronously displace n-a And epsilon n-c Unchanged epsilon n-b And epsilon (n-2)-d The increment value of epsilon is the same n-d And epsilon (n-2)-b The reduction value of (2) is the same; epsilon when the displacement amounts of the n-number segment ring 11 and the n-1 number segment ring 11 are different n-b And epsilon (n-2)-d May be different in the added value of epsilon n-d And epsilon (n-2)-b There will be a difference in the decrease value of epsilon n-a To a certain extent (depending on whether the n segment ring 11 is positively or negatively displaced) but with an increase of less than epsilon n-b The reduction amplitude is less than epsilon n-d ，ε n-c To a certain extent but with an increase of less than epsilon n-b The reduction amplitude is less than epsilon n-d The method comprises the steps of carrying out a first treatment on the surface of the Based on this, pass epsilon n-a～ ε n-d 、ε (n-2)-b 、ε (n-2)-d The increase or decrease of the number n segment ring 11 and the number n-1 segment ring 11 can accurately determine the difference in displacement amount.
When ε, as in FIG. 5 n-a 、ε n-b And epsilon (n+2)-a All increase and epsilon n-b Is the largest in increment and epsilon n-c And epsilon (n+2)-c When the displacement is reduced, the dislocation displacement of the n-number segment ring 11 and the n+1-number segment ring 11 is judged, wherein the n-number segment ring 11 is positively displaced, and the n+1-number segment ring 11 is negatively displaced; and otherwise, the n-number segment ring 11 and the n+1-number segment ring 11 are judged to be displaced in a dislocation manner, the n-number segment ring 11 is displaced in a negative direction, and the n+1-number segment ring 11 is displaced in a positive direction. Wherein the displacement of the n-number segment ring 11 is k 4 ε n-b ，k 4 Is the calibration coefficient. Epsilon n-d May exhibit various changes, for example, ε when the n segment ring 11 is displaced before the n+1 segment ring 11/the n segment ring 11 is displaced after the n+1 segment ring 11 n-d Generally, the trend of decreasing before increasing is shown, and epsilon is shown when the n-number segment ring 11 and the n+1-number segment ring 11 synchronously displace n-d In general, the displacement speeds of the n segment ring 11 and the n+1 segment ring 11 are differentExhibit additional strain changes, as can be seen by ε n-a ～ε n-d 、ε (n+2)-a 、ε (n+2)-c The increase or decrease of the number n segment ring 11 and the number n-1 segment ring 11 can accurately determine the difference in displacement amount.
Similarly, when ε n-a 、ε n-b And epsilon (n-2)-b All increase and epsilon n-a Is the largest in increment and epsilon n-d And epsilon (n-2)-d When the displacement is reduced, the dislocation displacement of the n-number segment ring 11 and the n-1 number segment ring 11 is judged, wherein the n-number segment ring 11 is positively displaced, and the n-1 number segment ring 11 is negatively displaced; and otherwise, the n-number segment ring 11 and the n-1-number segment ring 11 are judged to be displaced in a dislocation manner, wherein the n-number segment ring 11 is displaced in a negative direction, and the n-1-number segment ring 11 is displaced in a positive direction. Wherein ε n-c Many variations are possible and in particular no one-to-one analysis is made here.
Therefore, in this embodiment, reliable monitoring of the single segment ring 11 displacement, the multiple segment rings 11 displacement, and the dislocation displacement of the adjacent segment rings 11 can be realized, and the algorithm can calculate the data monitored by the displacement monitoring optical cable 201 and finally reverse the multidirectional displacement condition of the shield tunnel 1.
Example two
The embodiment of the invention provides a shield tunnel structure monitoring system based on an array grating, which can supplement and optimize the first embodiment.
As shown in fig. 6, the shield tunnel structure monitoring system includes a settlement monitoring module 2, a horizontal displacement monitoring module 3200, a regional crack monitoring module 5, and a convergence monitoring module 4.
The displacement monitoring module 200 of the first embodiment can be used as the sedimentation monitoring module 2 and/or the horizontal displacement monitoring module 3200, and the specific structure of the displacement monitoring module 200 is not described herein.
In one embodiment, the area crack monitoring module 5 comprises at least one crack monitoring optical cable that is a fiber grating array strain cable integrated with a plurality of fiber grating strain sensors; the crack monitoring optical cable is linearly distributed on the pipe wall of the shield tunnel 1 along the longitudinal direction of the tunnel. When there are a plurality of crack monitoring cables, each crack monitoring cable is preferably arranged at intervals in sequence along the circumferential direction of the tunnel.
The crack monitoring optical cable can be only laid in a key area, and can also be continuously laid along the whole length of the shield tunnel 1. The crack monitoring optical cable is preferably arranged on the inner side pipe wall of the shield tunnel 1, so that the crack monitoring optical cable is convenient to arrange and overhaul, and the influence of an external soil body and the like when the crack monitoring optical cable is arranged on the outer wall of the tunnel can be avoided. Preferably, as shown in fig. 6, the crack monitoring optical cable is fixedly connected with the pipe wall of the shield tunnel 1 through a plurality of optical cable installation units; the optical cable installation units capable of fixing the optical cable on the shield segment are applicable to the embodiment, for example, the optical cable installation units adopt wire buckles, wire clamps and the like, which are not exemplified herein; the optical cable mounting units are preferably distributed on the shield segment rings 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 mounting units is not fixedly connected with the wall of the tunnel, but is in a straightening state, so that the crack generation condition of the segment rings 11 can be rapidly and accurately sensed; in this design, at least one fiber grating strain sensor is included in the cable segment between two adjacent cable mounting units.
In one embodiment, the convergence monitoring module 4 comprises at least one convergence monitoring optical cable, which is a fiber grating array strain cable integrated with a plurality of fiber grating strain sensors; the convergence monitoring optical cable is annularly distributed on the pipe wall of the shield tunnel 1 along the circumferential direction of the tunnel. When there are a plurality of convergence monitoring cables, each convergence monitoring cable is preferably arranged at intervals in the longitudinal direction of the tunnel.
The convergence monitoring optical cable is preferably arranged on the inner side pipe wall of the shield tunnel 1, so that the convergence monitoring optical cable is convenient to arrange and overhaul, and the influence of an external soil body and the like when the convergence monitoring optical cable is arranged on the outer wall of the tunnel can be avoided. The convergence monitoring optical cable is preferably attached to the wall of the tunnel, and can be adhered to the wall of the tunnel or fixedly installed in other modes, or the wall of the tunnel is provided with a monitoring groove, and the convergence monitoring optical cable is buried in the monitoring groove and then is fixedly solidified by concrete.
The shield tunnel structure monitoring system provided by the embodiment can monitor the conditions of shield tunnel segment settlement, horizontal displacement, segment crack, clearance convergence and the like in real time, improves the service safety of the shield tunnel 1, and is convenient for the service department to overhaul and maintain the shield tunnel 1; the settlement monitoring module 2, the horizontal displacement monitoring module 3200, the regional crack monitoring module 5 and the convergence monitoring module 4 all adopt fiber bragg grating array strain cables, and the signal transmission lines of the fiber bragg grating strain sensors are unified and high in consistency, so that the accuracy of monitoring results can be improved.
Further preferably, as shown in fig. 6 and 7, each of the fiber grating array strain cables of the settlement monitoring module 2, the horizontal displacement monitoring module 3200, the area crack monitoring module 5 and the convergence monitoring module 4 is connected to a fiber grating data demodulator 61, and the fiber grating data demodulator 61 is configured to receive the strain information sent by each of the fiber grating array strain cables, demodulate the strain information into a demodulated signal, and send the demodulated signal to the background processor 62.
Further preferably, as shown in fig. 7, the shield tunnel structure monitoring system further includes a programmable alarm terminal 64, and the programmable alarm terminal 64 may be connected to the background processor 62 through a cable or wirelessly connected to the background processor 62 through a wireless transmission module 63. The background processor 62 analyzes and processes the demodulation signal and then determines whether to send an alarm command to the program-controlled alarm terminal 64; the program-controlled alarm terminal 64 is used for alarming after receiving the alarm instruction information sent by the background processor 62, and can be configured with alarm devices such as an audible and visual alarm.
Therefore, the shield tunnel structure monitoring system provided by the embodiment can realize the monitoring and early warning of the safety of the shield tunnel structure, is convenient for timely and accurately feeding back the monitored risk information, and is convenient for the implementation of a disposal linkage mechanism.
Example IV
The present embodiment provides an internal fixation type fiber grating protection device, which can be used in the above embodiments, for arranging the monitoring fiber optic cable on the tunnel pipe wall, for example, as the fixing device 7 therein.
As shown in fig. 8, the protection device comprises a protection shell, wherein a fiber grating inlet and a fiber grating outlet are arranged on the protection shell, a protection beam 73 is arranged in the protection shell, the protection beam 73 is an annular beam suitable for enclosing a sensor 2011 in the fiber grating 201, and a fiber grating penetration hole are arranged on the beam.
In one embodiment, the protection housing includes a bottom plate 71 and a cover plate 72, the protection beam 73 is disposed on the bottom plate 71, the cover plate 72 is detachably covered on the bottom plate 71, so that the fiber grating 201 to be protected can be enclosed in a housing cavity formed by enclosing the cover plate 72 and the bottom plate 71, and the protection effect is better. Wherein, optionally, the fiber grating inlet and the fiber grating outlet are both arranged on the bottom plate 71.
For the detachable connection between the bottom plate 71 and the cover plate 72, a threaded fastener such as a screw may be used for the connection; of course, snap-fit connection and the like are also possible.
Preferably, the base plate 71 is provided with a mounting portion, which may be a mounting hole or the like, so as to be mounted at the monitoring point.
When in use, the fiber bragg grating 201 sequentially passes through the fiber bragg grating inlet, the fiber bragg grating penetration hole and the fiber bragg grating outlet, preferably, the fiber bragg grating inlet, the fiber bragg grating outlet, the fiber bragg grating penetration hole and the fiber bragg grating penetration hole are coaxially arranged, so that the fiber bragg grating 201 can straightly pass through the protection device, and the accuracy and the reliability of a monitoring result are ensured.
In one embodiment, the protection beam 73 is an elastic beam body, and when encountering strong tension and compression deformation, the protection beam 73 is stressed first, and the elastic beam body can better perform the functions of energy dissipation and vibration reduction, so that the protection effect on the fiber grating 201 is better.
In one embodiment, as shown in fig. 8, the guard beams 73 are diamond beams. The diamond beam is adopted, so that the structural stability is high, the stress performance is more reliable, and the protection effect on the fiber bragg grating 201 can be further improved. Further, the fiber grating penetration holes and the fiber grating penetration holes are oppositely arranged at two corners of the diamond beam.
Further optimizing the protection means described above, as shown in fig. 8, a spring sleeve 75 is coaxially connected at the entrance of the fiber grating. The spring sleeve 75 is used for being connected with an external structure, so that the vibration reduction and buffering effects can be better achieved, and the protection effect of the protection shell is improved; the fiber grating 201 penetrates into the protective case from the spring sleeve 75, and the protection of the fiber grating 201 can be further enhanced. Preferably, the spring sleeve 75 includes a sleeve body and a spring accommodated in the sleeve body, the sleeve body can restrain and protect the spring, and the sleeve body can be made of a metal hose, a rubber tube or the like. The connection between the spring sleeve 75 and the protective housing includes, but is not limited to, threaded connection, bolting, interference fit connection, welding, etc.
Further optimizing the protection device, as shown in fig. 8, the armor tube 16 is arranged at the outlet of the fiber bragg grating, so that the protection of the fiber bragg grating 201 can be enhanced, and fiber fusion can be performed according to different monitoring objects, thereby realizing the aim of monitoring various physical quantities required by real-time measurement engineering.
Preferably, the protection beam 73 is detachably mounted in the protection housing, so that the installation and maintenance are convenient. In one embodiment, as shown in fig. 8, the guard beam 73 is mounted on a mounting plate 74, and the mounting plate 74 is detachably fixed in the protective housing, for example, by fixing pins to connect the mounting plate 74 and the protective housing. Based on the above structure, the protection beam 73 is configured as a cantilever beam, so that the protection beam 73 is prevented from being directly connected with the protection housing, the force transmission path can be further prolonged, and the influence of deformation, load, vibration and the like on the fiber grating 201 can be reduced. In another embodiment, the guard beam 73 may be fixed to the bottom plate 71 by the engagement of the mounting plate 74 and a stopper structure, such as a plurality of stopper pins.
The protection device provided by the embodiment fully surrounds and internally fixes the fiber grating 201, can effectively ensure the protection effect of the fiber grating 201, ensures that the state of the fiber grating 201 is kept stable, and improves the accuracy and reliability of the monitoring result. The protection device has simple structure and convenient installation, and can better adapt to engineering installation requirements.
The foregoing description of the preferred embodiments of the invention is not intended to be limiting, but rather is intended to cover all modifications, equivalents, alternatives, and improvements that fall within the spirit and scope of the invention.
Claims (5)
1. The shield tunnel structure monitoring method is characterized by being implemented based on a shield tunnel structure monitoring system, wherein the shield tunnel structure monitoring system comprises at least one group of displacement monitoring modules, each displacement monitoring module comprises two displacement monitoring optical cables, and each displacement monitoring optical cable is a fiber grating array strain cable integrated with a plurality of fiber grating strain sensors; the displacement monitoring optical cables are laid along the pipe wall of the shield tunnel, the two displacement monitoring optical cables are distributed in a waveform manner in the longitudinal direction of the tunnel, and the waveforms of the two displacement monitoring optical cables are reversed;
the wave crest and the wave trough 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 fixedly connected with the pipe wall of the shield tunnel through fixing devices, and the cable section between two adjacent fixing devices comprises at least one fiber bragg grating strain sensor;
the method comprises the following steps:
strain information is acquired in real time through the displacement monitoring optical cable, the strain information sent by the displacement monitoring optical cable is received through a fiber bragg grating data demodulator, demodulated into a demodulation signal and sent to a background processor;
the background processor analyzes and judges the structural health condition of the shield tunnel according to the demodulation signals so as to guide a working department to timely detect and maintain the shield tunnel;
sequentially numbering all segment rings along the longitudinal direction of the tunnel; in the two displacement monitoring optical cables of each group of displacement monitoring modules, the wave crest of the first displacement monitoring optical cable and the wave trough of the second displacement monitoring optical cable are far away from each other; judging the structural health condition of the shield tunnel by taking the segment ring of each wave crest of the first displacement monitoring optical cable as a monitoring reference;
collecting strain monitoring values of two adjacent sides of a wave crest of a first displacement monitoring optical cable as epsilon respectively n-a And epsilon n-b Strain monitoring values of two adjacent sides of the trough of the second displacement monitoring optical cable are epsilon respectively n-c And epsilon n-d Wherein n is the number of the segment ring where the wave crest of the first displacement monitoring optical cable is located;
when epsilon n-a And epsilon n-b Increase, epsilon n-c And epsilon n-d When the number n segment ring is reduced, judging that the number n segment ring is subjected to forward displacement, wherein the forward displacement is the crest convex direction of the first displacement monitoring optical cable; otherwise, judging that the n-number segment ring is subjected to negative displacement;
when epsilon n-b And epsilon (n+2)-a Reduction, epsilon n-d And epsilon (n+2)-c When the number n+1 segment ring is increased, judging that the number n+1 segment ring is positively displaced; otherwise, judging that the n+1 segment ring is subjected to negative displacement;
when epsilon n-a And epsilon (n+2)-c Increase, epsilon n-c And epsilon (n+2)-a When the number n and the number n+1 segment rings are reduced, judging that the number n segment rings are positively displaced; otherwise, judging that the two are in negative displacement;
when epsilon n-b And epsilon (n-2)-d Increase, epsilon n-d And epsilon (n-2)-b When the number n and the number n-1 segment rings are reduced, judging that the number n and the number n-1 segment rings are positively displaced; otherwise, judging that the two are in negative displacement;
when epsilon n-a 、ε n-b And epsilon (n+2)-a All increase and epsilon n-b Is the largest in increment and epsilon n-c And epsilon (n+2)-c When the displacement is reduced, the dislocation displacement of the n-number segment ring and the n+1-number segment ring is judged, and the n-number segment ring is positively displaced; otherwise, judging that the n-number segment ring and the n+1-number segment ring are displaced in a dislocation manner, and enabling the n-number segment ring to be displaced in a negative direction;
when epsilon n-a 、ε n-b And epsilon (n-2)-b All increase and epsilon n-a Is the largest in increment and epsilon n-d And epsilon (n-2)-d When the number is reduced, the number n segment ring and the number n-1 tube are judgedThe segment rings are displaced in a dislocation way, and n segment rings are positively displaced; and otherwise, judging that the n-number segment ring and the n-1-number segment ring are displaced in a dislocation manner, and enabling the n-number segment ring to be displaced in a negative direction.
2. The shield tunnel structure monitoring method of claim 1, wherein: the displacement monitoring optical cable is distributed in a sawtooth waveform.
3. The shield tunnel structure monitoring method of claim 1, wherein: in the displacement monitoring module, the wave crest of one of the displacement monitoring optical cables and the wave trough of the other one of the displacement monitoring optical cables are fixed through the same fixing device.
4. The shield tunnel structure monitoring method of claim 1, wherein: each displacement monitoring optical cable is laid on the inner side pipe wall of the shield tunnel.
5. A shield tunnel structure monitoring method according to any one of claims 1 to 4, wherein: the displacement monitoring modules comprise a plurality of groups and comprise sedimentation monitoring modules and horizontal displacement monitoring modules, wherein the sedimentation monitoring modules are arranged at the waist of the tunnel, and the horizontal displacement monitoring modules are arranged at the top or the bottom of the tunnel.
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