Embedded distributed optical fiber monitoring unit, system and method for subway station

Abstract

The invention relates to the field of optical fiber monitoring, and provides an embedded distributed optical fiber monitoring unit, system and method for a subway station, and the monitoring unit comprises an optical fiber and two junction boxes. The junction boxes are arranged at two ends of the optical fiber, and rotating rods are mounted in the junction boxes; the optical fiber in the junction box is a reserved optical fiber, the reserved optical fiber is rotationally wound on a rotating rod, and the rotating rod is used for providing set tensile force for the optical fiber; and the optical fiber between the two junction boxes is pre-embedded in the pouring structure. The reserved optical fiber is ingeniously wound on the rotating rod controlled by the spiral spring, certain tension stress is kept before concrete pouring, and the distributed optical fiber monitoring precision is remarkably improved; the junction box not only can be connected with the adjacent optical fiber monitoring units, but also has the capability of replacing the damaged optical fiber units, and the damaged parts can be replaced by earth surface optical fiber lines at any time, so that the damage of the whole distributed optical fiber caused by force majeure in the construction process is effectively prevented, and the loss of the effective monitoring units is reduced.

Description

Technical Field

[0001] The present invention relates to the field of optical fiber monitoring, and in particular to an embedded distributed optical fiber monitoring unit, system and method for a subway station. Background Art

[0002] With the accelerated advancement of urbanization, urban underground space has been fully utilized, and subway construction has continued to increase. Subway stations are generally located in densely populated areas and require huge investments. During the construction of subway stations, once safety problems occur, it will pose a huge threat to the safety of life and property. Therefore, during the construction of subway stations, it is very important to achieve highly accurate structural monitoring, especially accurate monitoring of the stress and strain of station structures. This can effectively prevent potential problems and ensure safety and reliability during the construction of subway stations.

[0003] Distributed fiber technology, as an advanced method that uses optical fiber as a sensing element to monitor physical environment changes in real time by measuring the specific properties of optical signals in optical fiber, has shown excellent application prospects in many fields. Compared with traditional monitoring methods such as vibrating wire sensors and strain gauges, distributed fiber has a series of remarkable advantages, including 24-hour uninterrupted monitoring, high scalability, a wide range of remote monitoring, excellent perception sensitivity, excellent cost-effectiveness, strong anti-electromagnetic interference performance, superior electroplating insulation, and the ability to fully cover monitoring. The application of distributed fiber in subway station monitoring is gradually increasing.

[0004] However, there are still some problems in applying distributed optical fiber to subway station construction monitoring. During the monitoring process of subway stations, optical fibers need to be arranged in the steel cage before the concrete is poured. However, once the optical fiber is fixed in the steel cage, the preset tension stress of the optical fiber may relax or even be damaged due to the inevitable interference of the steel cage by subsequent construction. In addition, the expensive demodulator cost leads to limited optical fiber interfaces, and the optical fiber may need to be very long in order to cover the entire subway station. Once the concrete is poured, the optical fiber cannot be replaced. Therefore, if a part of the optical fiber is damaged, it will cause the optical path to be interrupted, affecting other normal optical fiber monitoring.

[0005] To address these issues, developing an embedded distributed optical fiber monitoring unit for subway stations has important engineering significance. Summary of the invention

[0006] The purpose of the present invention is to overcome the shortcomings of the prior art and provide an embedded distributed optical fiber monitoring unit, system and method for subway stations, which can effectively prevent the damage of the entire distributed optical fiber caused by force majeure during the construction process and reduce the loss of effective monitoring units.

[0007] The present invention adopts the following technical solution:

[0008] On the one hand, the present invention provides an embedded distributed optical fiber monitoring unit for a subway station, comprising an optical fiber and two junction boxes; the junction boxes are arranged at both ends of the optical fiber, and a rotating rod is installed inside the junction boxes; the optical fiber in the junction box is a reserved optical fiber, the reserved optical fiber is rotatably wound on the rotating rod, and the rotating rod is used to provide a set tensile force for the optical fiber; the optical fiber between the two junction boxes is pre-buried in the cast structure.

[0009] As described above in any possible implementation manner, an implementation manner is further provided, wherein the rotary rod is arranged on a base, the base is fixed to the bottom of the junction box, and an openable box cover is arranged on the top of the junction box.

[0010] As any possible implementation described above, an implementation is further provided, wherein the optical fiber is connected to the interior of the junction box through a small hole on the side of the junction box, and the end of the optical fiber is fixed to the fixed end at the bottom of the rotating rod.

[0011] Any possible implementation as described above, further provides an implementation, wherein the rotating rod is connected to the base via a coil spring, the coil spring sets a tension threshold range, and the tension threshold range includes a high tension value and a low tension value; when the optical fiber tension is higher than the high tension value, the rotating rod rotates in one direction to release part of the reserved optical fiber wound on the rotating rod, and the optical fiber tension is reduced to within the threshold range; when the optical fiber tension is lower than the low tension value, the rotating rod rotates in the opposite direction to increase the length of the reserved optical fiber wound on the rotating rod, and the optical fiber tension is increased to within the threshold range.

[0012] Any possible implementation as described above further provides an implementation, wherein the optical fiber tension range is 50±10N.

[0013] Any possible implementation as described above further provides an implementation, wherein the coil spring is a high-strength spring, which is arranged on a fixed rod, and the fixed rod is fixed to the upper part of the base; the rotating rod is a hollow structure, which is mounted on the fixed rod and connected to the coil spring.

[0014] On the other hand, the present invention also provides an embedded distributed optical fiber monitoring system for subway stations, including external detection equipment, and several of the above-mentioned monitoring units; the optical fiber ends in the junction boxes of the several detection units are connected in series in sequence, and the optical fiber ends of the two outermost detection units after the series connection are connected to the external detection equipment.

[0015] As any possible implementation described above, there is further provided an implementation, wherein the external detection device includes a fiber optic demodulator and a display terminal.

[0016] On the other hand, the present invention further provides a buried distributed optical fiber monitoring method for a subway station, the monitoring method using the buried distributed optical fiber monitoring system for a subway station, the monitoring method comprising:

[0017] S1. Design the entire distributed optical fiber into several sections according to the requirements, and prepare the distributed optical fiber according to the length of each section;

[0018] S2, placing a section of distributed optical fiber into the template of the structure to be cast, connecting the two ends of the distributed optical fiber to the junction box respectively, winding the reserved optical fiber at the end on the rotating rod, and adjusting the threshold of the spiral spring connected to the rotating rod;

[0019] S3, repeat step S2 until all optical fiber units of the entire distributed optical fiber are arranged;

[0020] S4. After the pouring is completed and the structure is hardened, the junction box covers of all optical fiber units are opened, and adjacent distributed optical fiber monitoring units are welded to connect all distributed optical fiber monitoring units in series;

[0021] S5. After the fusion splicing is completed, the distributed optical fiber is connected to the demodulator for inspection to identify whether there is a distributed optical fiber monitoring unit damaged due to force majeure during construction; if damage is found, the distributed optical fiber monitoring unit is excluded, and then the two adjacent distributed optical fiber monitoring units are connected through the ground optical fiber.

[0022] As any possible implementation described above, a further implementation is provided, in which in step S2, the distributed optical fiber is arranged in a steel cage of the structure template to be cast.

[0023] The beneficial effects of the present invention are:

[0024] Compared with the existing distributed optical fiber, the entire distributed optical fiber is innovatively divided into several sections. By installing junction boxes at both ends of the optical fiber, reserving optical fibers inside the junction boxes, and then cleverly winding them on the rotating rod controlled by the spiral spring, it effectively prevents the optical fiber from being damaged due to excessive stress or the monitoring accuracy is reduced due to too low stress, thereby improving the optical fiber monitoring accuracy. At the same time, the junction box can not only connect adjacent optical fiber monitoring units, but also has the ability to replace damaged optical fiber units. This allows the surface optical fiber line to replace the damaged part at any time, thereby effectively preventing the entire distributed optical fiber from being damaged due to force majeure during the construction process and reducing the loss of effective monitoring units. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 Shown is a schematic structural diagram of an embedded distributed optical fiber monitoring unit for a subway station according to an embodiment of the present invention.

[0026] Figure 2 This is a schematic diagram of the internal structure of the junction box;

[0027] Figure 3 It is a three-dimensional schematic diagram of a distributed optical fiber monitoring unit;

[0028] Figure 4 This is a schematic diagram of the overall layout of distributed optical fiber monitoring;

[0029] Explanation of the reference numerals: 1-optical fiber, 2-junction box, 3-box cover, 4-rotating rod, 5-optical fiber fixing end, 6-reserved optical fiber, 7-base, 8-fixing screw, 9-sealing ring, 10-screw hole, 11 high-strength coil spring, 12-fixing rod, 13-optical fiber demodulator, 14-display terminal. DETAILED DESCRIPTION

[0030] The specific embodiments of the present invention will be described in detail below in conjunction with specific drawings. It should be noted that the technical features or combinations of technical features described in the following embodiments should not be considered isolated, and they can be combined with each other to achieve better technical effects.

[0031] like Figure 1 , Figure 3 As shown, an embodiment of the present invention is an embedded distributed optical fiber monitoring unit for a subway station, comprising an optical fiber 1 and two junction boxes 2; the junction boxes 2 are arranged at both ends of the optical fiber 1, and a rotating rod 4 is installed inside the junction box 2; the optical fiber 1 in the junction box 2 is a reserved optical fiber, and the reserved optical fiber is rotatably wound on the rotating rod 4, and the rotating rod 4 is used to provide a set tensile force for the optical fiber 1; the optical fiber 1 between the two junction boxes 2 is pre-buried in the cast structure.

[0032] In a specific embodiment, the rotary rod 4 is disposed on a base 7 , the base 7 is fixed to the bottom of the junction box 2 , and an openable box cover 3 is disposed on the top of the junction box 2 .

[0033] In a specific embodiment, the optical fiber 1 is connected to the inside of the junction box 2 through a small hole on the side of the junction box 2 , and the end of the optical fiber 1 is fixed to the fixed end at the bottom of the rotating rod 4 .

[0034] In a specific embodiment, the rotating rod 4 is connected to the base 7 through a coil spring 11, and the coil spring 11 sets a tension threshold range, and the tension threshold range includes a high tension value and a low tension value; when the tension of the optical fiber 1 is higher than the high tension value, the rotating rod 4 rotates in one direction to release part of the reserved optical fiber wound on the rotating rod 4, and the tension of the optical fiber 1 is reduced to within the threshold range, while preventing the optical fiber 1 from being damaged; when the tension of the optical fiber 1 is lower than the low tension value, the rotating rod 4 rotates in the opposite direction to increase the length of the reserved optical fiber wound on the rotating rod 4, and the tension of the optical fiber 1 is increased to within the threshold range.

[0035] In a specific embodiment, the tension range of the optical fiber 1 is 50±10N.

[0036] In a specific embodiment, Figure 2 As shown, the coil spring 11 is a high-strength spring, which is arranged on a fixing rod 12, and the fixing rod 12 is fixed to the upper part of the base 7; the rotating rod 4 is a hollow structure, which is mounted on the fixing rod 12 and connected to the coil spring 11. Except for the initial position, the coil spring 11 has resistance to rotation in both directions, so it is converted into tension so that the tension on the optical fiber 1 is kept within a certain range.

[0037] In a specific embodiment, the base 7 is fixed to the bottom of the junction box 2 by welding.

[0038] like Figure 4 As shown, an embodiment of the present invention is an embedded distributed optical fiber monitoring system for a subway station, comprising an external detection device, and a plurality of the above-mentioned monitoring units; the ends of the optical fibers 1 in the junction boxes 2 of the plurality of the detection units are sequentially connected in series, and the ends of the optical fibers 1 of the two outermost detection units after the series connection are connected to the external detection device.

[0039] In a specific embodiment, the external detection device includes a fiber optic demodulator 13 and a display terminal 14 .

[0040] An embodiment of the present invention provides an embedded distributed optical fiber monitoring method for a subway station, using the above-mentioned embedded distributed optical fiber monitoring system for a subway station. The monitoring method includes:

[0041] S1. Design the entire distributed optical fiber into several sections according to the requirements, and prepare the distributed optical fiber 1 according to the length of each section;

[0042] S2, placing a section of distributed optical fiber 1 into the template of the structure to be cast, connecting the two ends of the distributed optical fiber 1 to the junction box 2 respectively, winding the reserved optical fiber 1 at the end on the rotating rod 4, and adjusting the threshold of the spiral spring 11 connected to the rotating rod 4;

[0043] S3, repeating step S2 until all distributed optical fiber monitoring units of the entire distributed optical fiber are arranged;

[0044] S4. After the pouring is completed and the structure is hardened, the covers of the junction boxes 2 of all the optical fiber units are opened, and the adjacent distributed optical fiber monitoring units are welded to connect all the distributed optical fiber monitoring units in series;

[0045] S5. After the fusion splicing is completed, the distributed optical fiber 1 is connected to the optical fiber demodulator 13 for inspection to identify whether there is a distributed optical fiber monitoring unit damaged due to force majeure during construction; if damage is found, the distributed optical fiber monitoring unit is excluded, and then the two adjacent distributed optical fiber monitoring units are connected through the ground optical fiber.

[0046] In a specific embodiment, in step S2, the distributed optical fiber 1 is arranged in a steel cage of a structure template to be cast.

[0047] The purpose of maintaining the tension of optical fiber 1 before pouring is to ensure the measurement accuracy of optical fiber 1, so that the tensile deformation and compressive deformation of concrete can be accurately measured at the same time. After pouring, it is not necessary to maintain the tension of the optical fiber, because the optical fiber and concrete have become a whole and no relative displacement occurs. Therefore, the deformation of concrete can be measured by the deformation of optical fiber 1.

[0048] The present invention innovatively divides the entire distributed optical fiber into several sections, installs a junction box 2 at both ends of the optical fiber 1, reserves optical fibers inside the junction box 2, and then cleverly winds them around the rotating rod 4 controlled by the spiral spring 11, effectively preventing the optical fiber 1 from being damaged due to excessive stress or the monitoring accuracy from being reduced due to excessive stress, thereby improving the optical fiber monitoring accuracy. At the same time, the junction box 2 can not only connect adjacent optical fiber monitoring units, but also has the ability to replace damaged optical fiber units.

[0049] Although several embodiments of the present invention have been given herein, those skilled in the art should understand that the embodiments of the present invention may be modified without departing from the spirit of the present invention. The above embodiments are merely exemplary and should not be used as a limitation on the scope of the present invention.

Claims

1. An embedded distributed optical fiber monitoring unit for a subway station, characterized in that: The monitoring unit includes an optical fiber and two junction boxes; the junction boxes are arranged at both ends of the optical fiber, and a rotating rod is installed inside the junction box; the optical fiber in the junction box is a reserved optical fiber, the reserved optical fiber is rotated and wound on the rotating rod, and the rotating rod is used to provide a set tensile force for the optical fiber; the optical fiber between the two junction boxes is pre-buried in the cast structure.

2. The embedded distributed optical fiber monitoring unit for a subway station as claimed in claim 1, characterized in that: The rotating rod is arranged on the base, the base is fixed to the bottom of the junction box, and an openable box cover is arranged on the top of the junction box.

3. The embedded distributed optical fiber monitoring unit for a subway station as claimed in claim 1, characterized in that: The optical fiber is connected to the inside of the junction box through a small hole on the side of the junction box, and the end of the optical fiber is fixed on the fixed end at the bottom of the rotating rod.

4. The embedded distributed optical fiber monitoring unit for a subway station as claimed in claim 1, characterized in that: The rotating rod is connected to the base through a coil spring, and the coil spring sets a tension threshold range, and the tension threshold range includes a high tension value and a low tension value; when the optical fiber tension is higher than the high tension value, the rotating rod rotates in one direction to release part of the reserved optical fiber wound on the rotating rod, and the optical fiber tension is reduced to within the threshold range; when the optical fiber tension is lower than the low tension value, the rotating rod rotates in the opposite direction to increase the length of the reserved optical fiber wound on the rotating rod, and the optical fiber tension is increased to within the threshold range.

5. The embedded distributed optical fiber monitoring unit for a subway station as claimed in claim 4, characterized in that: The optical fiber tension range is 50±10N.

6. The embedded distributed optical fiber monitoring unit for a subway station according to claim 1, characterized in that: The coil spring is a high-strength spring, which is arranged on a fixed rod, and the fixed rod is fixed to the upper part of the base; the rotating rod is a hollow structure, which is sleeved on the fixed rod and connected to the coil spring.

7. An embedded distributed optical fiber monitoring system for a subway station, characterized in that: The system includes an external detection device and several monitoring units as described in any one of claims 1 to 6; the optical fiber ends in the junction boxes of the several detection units are connected in series in sequence, and the optical fiber ends of the two outermost detection units after the series connection are connected to the external detection device.

8. The embedded distributed optical fiber monitoring system for a subway station as claimed in claim 7, characterized in that: The external detection equipment includes an optical fiber demodulator and a display terminal.

9. A buried distributed optical fiber monitoring method for a subway station, characterized in that: The monitoring method uses the buried distributed optical fiber monitoring system for a subway station as claimed in claim 7 or 8, and the monitoring method comprises: S1. Design the entire distributed optical fiber into several sections according to the requirements, and prepare the distributed optical fiber according to the length of each section; S2. Place a section of distributed optical fiber into the template of the structure to be cast, connect the two ends of the distributed optical fiber to the junction box respectively, wind the reserved optical fiber at the end onto the rotating rod, and adjust the tension threshold of the spiral spring connected to the rotating rod; S3, repeating step S2 until all distributed optical fiber monitoring units of the entire distributed optical fiber are arranged; S4. After the pouring is completed and the structure is hardened, the junction box covers of all optical fiber units are opened, and adjacent distributed optical fiber monitoring units are welded to connect all distributed optical fiber monitoring units in series; S5. After the fusion splicing is completed, the distributed optical fiber is connected to the optical fiber demodulator for inspection to identify the damaged distributed optical fiber monitoring unit; if damage is found, the distributed optical fiber monitoring unit is excluded, and then the two adjacent distributed optical fiber monitoring units are connected through the ground optical fiber.

10. The buried distributed optical fiber monitoring method for a subway station as claimed in claim 9, characterized in that: In step S2, the distributed optical fiber is arranged in the steel cage of the structure template to be cast.

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