JP2000030162A - Defense management system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an economical and stable defense management which is easy to perform wiring processing, has high sensitivity and a long signal transmission distance, does not require wireless relay, and does not have to worry about malfunction due to induced electromagnetic noise. Provide system. SOLUTION: A strain sensor unit 10 having a fiber grating type optical fiber sensor as a detection element is attached to a wire rope net unit 1 having an energy absorbing mechanism stretched for disaster prevention, and the amount of distortion is changed by the Bragg wavelength. Utilizing such characteristics, the distortion is detected by the distortion measuring device 3, the danger state is diagnosed by the processing unit 4, and a predetermined notification and alarm are issued.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention aims to prevent accidents such as falling rocks, avalanches, and traffic accidents and to prevent damage from spreading immediately after an accident occurs. The present invention relates to a defense management system that performs the following.

[0002]

2. Description of the Related Art As a conventional defense management system, a surveillance system using a surveillance camera, a strain gage, a capacitance measurement, and the like are used to prevent a wire rope from being stretched for disaster prevention.
There are systems for detecting displacement and load. Also,
There is a strain detection system using a Brillouin scattering method using an optical fiber as a sensor.

[0003]

These surveillance cameras and methods for electrically processing strain, displacement and load are vulnerable to induced electromagnetic noise when used outdoors, and are used in places where lightning occurs. There were drawbacks that could not be done. In addition, when using the electrical detection method in a remote place such as a mountainous area, it is necessary to install an amplifier or convert to a radio signal and transmit it to a remote observation station because the length of the signal line is limited. However, there are problems in the construction cost of the monitoring system, and in the operation and maintenance of the system. For example, using a rockfall information management system, place a net-shaped wire rope on the rock to prevent rockfall to prevent rockfall, and connect the end of the wire rope to the anchor bolt to measure the load on the wire rope that has been constructed. In the case of systems that use monitoring, rock fall prevention target locations are often remote places or high places, and in the method using the above-mentioned radio for relaying, the radio wave condition is bad during concentrated heavy rain with lightning strikes, There have been problems that rock fall cannot be detected at the most important moment, or that the device malfunctions. Further, as a problem of the electric sensor, a wiring process when a large number of sensors are used is not easy.

As a known method, there is a method of using the frequency change of the Brillouin scattered light of the optical fiber for detecting the strain of the optical fiber. Had problems.

[0005] Therefore, an object of the present invention is to provide a defense management system that solves the problems when a surveillance camera, an electric sensor, and an optical fiber sensor are used.
In other words, it is not affected by induced electromagnetic noise or lightning, the construction of a monitoring system is inexpensive, easy to maintain and manage, it can prevent malfunctions, the wiring process is easy, and the detection sensitivity for detecting dynamic fluctuation is high. The task is to provide a defense management system.

[0006]

In order to solve the above-mentioned problems, a defense management system according to the present invention detects one or more wire ropes stretched for disaster prevention, and detects a distortion of the wire ropes. A strain sensor unit using a fiber grating type optical fiber sensor for detecting the magnitude of the strain generated in the fiber grating type optical fiber sensor by using the characteristic of changing the Bragg wavelength; A signal transmission optical fiber cable connecting between the sensor unit and the strain measuring device, a processing unit for performing a predetermined process based on a signal from the strain measuring device, and a signal processing unit based on a signal transmitted from the processing unit. And a warning unit for reporting danger.

The fiber grating method (hereinafter abbreviated as FBG method) is a method in which a fiber grating in which the refractive index of a core portion (diameter of about 9 μm) of a communication single mode optical fiber is periodically changed in the fiber axis direction is used as a detection element. It is used. It utilizes a phenomenon in which only a specific wavelength (Bragg wavelength) corresponding to the period of the refractive index is selectively reflected in fiber gratings among the light entering the detection element, and the detection element section When a strain is applied to the fiber grating (having a length of, for example, 10 mm), the frequency of the reflected light shifts because the period of the fiber grating changes. Therefore, the applied strain can be measured from the wavelength shift. Unlike the Brillouin scattering method, the FBG method can detect dynamic strain on the order of microstrain, and a fiber grating type optical fiber sensor (hereinafter abbreviated as FBG sensor) using the FBG method has excellent detection sensitivity.

[0008] The strain sensor unit can be configured to be attached to the surface of the wire rope or to be connected between the wire ropes.

[0009] In addition, a shock absorber that absorbs energy through extension of the wire rope when a predetermined tension or more is applied to the wire rope is interposed between the wire rope and the anchor bolt. Can be.

Further, a plurality of wire ropes are stretched vertically and horizontally, and the vertical wire ropes and the horizontal wire ropes are sandwiched and connected by a buffer at an intersection, and when a certain force or more is applied to the intersection. In addition, it is possible to adopt a configuration in which the buffering tool moves along a vertical wire rope or a horizontal wire rope to perform a buffering action while maintaining a constant holding force.

Also, a configuration using a plurality of the above FBG sensors in series or in parallel can be adopted. In particular, F
The serialization of the BG sensors has the characteristic that it can be realized using one optical fiber, and the wiring process can be simplified.

Note that, in order to cancel a change in the detected value due to a temperature change, the strain sensor section may have a configuration in which an optical fiber sensor for temperature compensation is installed near the optical fiber sensor section for strain detection. The temperature compensating optical fiber sensor may be configured to be fixed to the substrate at two points with a free or extra length so that the detection element portion is not restrained by the substrate. In addition, the strain sensor unit may have a structure in which the FBG sensor is bonded and fixed to a part formed of a material having the same linear expansion coefficient and elastic coefficient as the wire rope or the optical fiber.

Further, in the above-described processing of the detection signal, when the value of the detection signal exceeds a predetermined value, a processing for issuing a predetermined notification and an alarm can be performed. In addition, if the amount of change in the detection signal per unit time exceeds a certain value, so as to catch the sudden change in the detection signal due to an accident, ignore the gentle change in the detection signal due to temperature change, etc.
Processing such as reporting a danger can be performed.

As described above, the present invention is characterized in that the dynamic strain of a wire rope having an energy absorbing mechanism is measured. That is, since the wire rope has an energy absorbing mechanism, it is not easily broken. In addition, by using the change in the moving point of the distortion amount for a predetermined notification or warning signal, it is possible to avoid the level fluctuation and the influence of the environmental temperature due to the aging of the FBG sensor. With such advantages, the reliability of the defense management system is improved.

Further, since the sensor section and the signal transmission path are optical fibers, they are not affected by lightning strikes or other induced electromagnetic noise, and can transmit signals over long distances, eliminating the need for a relay facility to the observation station. The system construction cost is lower than that of a system using an electrical detection method. Further, the processing unit is connected to the central monitoring center through the public network, and can collectively manage information on different points in different areas, thereby facilitating maintenance and management.

By the above means, the wiring processing is easy, the sensitivity is long, the signal transmission distance is long, the need for wireless relay is eliminated, and there is no risk of malfunction due to induced electromagnetic noise. A defense management system can be realized.

[0017]

Embodiment

Embodiment 1 (rockfall information management system) FIG. 1 is a diagram for explaining a first embodiment, and shows a configuration in which the present invention is applied to a rockfall information management system. Numeral 1 denotes a rock fall prevention wire net portion, and a strain sensor portion 10 accommodating an FBG sensor for detecting a strain of the wire rope is attached to appropriate places between the wire net portion 1 and the anchor bolts. FIG.
Is a diagram showing the configuration of the rock fall prevention wire net portion 1. A plurality of wire ropes 7 are stretched lengthwise and breadthwise, and the whole is formed into a net shape. The end of the rope located around 1 is connected to an anchor bolt 9 fixed to the ground via a buffer 8. Reference numeral 11 denotes a stopper for preventing the wire rope 7 from coming off. A strain sensor unit 10 provided in the wire net unit 1 and a strain measuring device 3 provided apart from the wire net unit 1 are connected by an optical fiber cable 2 for signal transmission. 4 is a processing unit, 5 is an alarm device for notifying danger, and 6 is a warning display device. The alarm unit includes an alarm device 5 and a warning display device 6.

FIG. 3 is a view showing a mounting state of the shock absorber 8. The shock absorber 8 is mounted between the wire rope 7 and the anchor bolt 9 so as to connect them. FIG. 4 is an exploded view showing the structure of the shock absorber 8. The upper half portion 22 and the lower half portion 23 of the shock absorber 8 are held by holding the wire rope 7 in the groove 24, the fastener 25 is passed through the hole 26, and the upper half portion 22 and the lower Half 2
The wire rope 7 is clamped with a constant force by tightening and adjusting the wire rope 3. When a certain force or more is applied in the longitudinal direction of the wire rope between the wire rope 7 and the shock absorber 8, the extra length of the wire rope 7 provided with the slack between the shock absorber 8 and the stopper 11 becomes shock-absorbing. The inside of the tool 8 is slipped to perform a buffering action. During the slip, the shock absorber 8 holds the wire rope 7 with a constant force.

Further, the vertical wire rope and the horizontal wire rope are sandwiched and connected by a buffer 12 at the intersection. When a certain force or more is applied between these wire ropes and the shock absorber 12 at the intersection, the shock absorber 12 keeps a constant holding force, and moves along the vertical wire rope or the horizontal wire rope. It is structured to move and perform a buffering action. For example, when a certain force or more is applied to the shock absorber 12 at an arbitrary position in FIG. 2 in the upper right direction, the shock absorber 12 moves upward along the vertical wire rope and rightward along the horizontal wire rope. Go to The shock absorber 12 can be realized, for example, by connecting two shock absorbers 8 orthogonally.

FIG. 5 shows a distortion detecting F in the distortion sensor unit 10.
FIG. 2 is a diagram illustrating a configuration of a BG sensor (hereinafter, abbreviated as a strain sensor). The strain sensor includes a detection element unit 13 and a substrate 14. The detection element unit 13 is stuck on the substrate 14 in close contact, and both ends of the detection element unit 13 are fixed on the substrate 14 by the adhesive 15. In this state, the detection element section 13 is affected by thermal distortion of the substrate 14.

The optical fiber sensor of the present invention is characterized by using the FBG method. As for the light that has entered the detection element unit 13, only the light having the predetermined intrinsic wavelength λ1 is reflected by the detection element unit 13. At this time, if strain is applied to the detection element section 13, the wavelength ΔΔ is proportional to the amount of strain ε.
And the reflected light becomes λ1 + Δ. Therefore, detecting the distortion amount ε is equivalent to measuring Δ.

Simultaneously, in the multi-point measurement, one optical fiber is wired so as to pass through a number of strain measurement points in a single-stroke manner, and at each of the strain measurement points, the specific wavelength is λ.
It becomes possible by connecting a plurality of detection element sections 13 different from 1, λ2, λ3, λ4,. That is, the measurement location is determined by the specific wavelength λ, and the distortion amount is determined by the wavelength shift Δ of each detection element unit 13. Connecting in series to an optical fiber simplifies wiring connection. Note that the specific wavelengths are λ1,
a plurality of detection element portions 1 different from λ2, λ3, λ4,.
3 can be connected in parallel to perform simultaneous and multipoint measurement.

The detection element section 13 in the FBG method is very sensitive not only to distortion but also to temperature changes. Therefore, unless temperature compensation similar to that of a strain gauge is performed, it is impossible to measure only the target strain amount. Next, the temperature compensation method which is most problematic in practical use will be described.

FIG. 6 shows an optical fiber sensor for temperature compensation (hereinafter abbreviated as temperature sensor). The detection element 13 is a substrate 14
It is fixed on the substrate 14 at two points in a loose state or with an extra length so as not to be restricted by the above. With this structure, the detection element section 13 is not affected by the thermal strain of the substrate 14, and the wavelength shift amount depends only on the thermal expansion of the detection element section 13. Therefore, it works as an accurate temperature sensor. By installing this temperature sensor near the strain sensor in the strain sensor unit 10 and accurately measuring the ambient temperature,
It is possible to accurately calculate the thermal distortion amount of the detection element unit 13 and the substrate 14 whose temperature dependence is known in advance, and to detect the accurate temperature-compensated distortion amount by subtracting from the detection value of the distortion sensor. it can.

The operation of the defense management system of the present invention is as follows. The optical signal for observation is sent to the distortion sensor unit 10 from the distortion measuring device 3 via the transmission optical fiber cable 2 at regular intervals. When the disaster prevention wire rope 7 receives some tension, a distortion corresponding to the tension is generated.
The strain generated in the wire rope 7 is transmitted to the strain sensor unit 10, and the Bragg wavelength of the FBG sensor changes. The wavelength of the optical signal for observation reflected by the distortion sensor unit 10 is measured by the distortion measuring device 3, and the wavelength shift Δ is converted into a distortion amount and output. Based on this output signal, the processing unit 4 determines which part of the rock is in a dangerous state in the processing unit 4, and in the event of a danger, an alarm device 5 or a warning display device installed on the road. By activating 6 etc., the danger of falling rocks can be reported and accidents due to falling rocks can be prevented. Also, the output signal is sent to the central management center through the public telephone network.
Since information on different areas and different points can be managed collectively, accident prevention measures can be taken promptly even in remote locations.

The rockfall information management system having the above-described structure can control the impact force of the shock absorber 8 even if the rock to be rocked falls into a separated rockfall state due to an earthquake, heavy rain, or the like.
It can be absorbed by the slip of the extra length of the wire rope 7 in the inside or the slip of the wire rope 7 in the shock absorber 12, and the cutting of the wire rope 7 and the pulling out of the anchor bolt 9 can be suppressed. Also, FBG
Since the sensor has high sensitivity and a long signal transmission distance, there is no need for wireless relaying. It is possible to determine whether there is a small object, make an appropriate report, notify the danger of falling rocks, and prevent accidents due to falling rocks. Furthermore, based on the detection value of the sensor, even if the possibility of falling rocks is small,
By judging the necessity of rework of the prevention work, management of the rock fall prevention work can be easily performed.

In particular, in order to accurately judge the state of the wire rope 7 having the energy absorbing mechanism, it is extremely important to measure the amount of dynamic strain. FIG. 7 is a diagram showing a state of distortion of the wire rope 7 at the time of falling rock. The graph shows the time change of the distortion amount. When a falling rock occurs and collides with the wire rope 7, the amount of distortion of the wire rope 7 increases, and the wire rope 7 starts to slip from a point where a predetermined value is exceeded. At this time, the tension varies due to the unevenness of the wire of the wire rope 7, and the amount of distortion also varies. The amount of distortion gradually decreases with the absorption of energy, converges to a substantially constant value, and the slip ends. By capturing such an instantaneous change in strain, it is possible to avoid the secular change of the detected value of the strain sensor and the influence of the environmental temperature. In addition, by providing a temperature compensation function, reliability can be further improved.

[0028]

Second Embodiment (Avalanche Information Management System) FIG. 8 is a view for explaining a second embodiment, and shows a configuration in which the present invention is applied to an avalanche information management system. An avalanche prevention fence 16 is fixed to an avalanche prevention target area of a snowy mountain by an anchor bolt 9. In order to prevent the avalanche prevention fence 16 from overturning, the wire rope 7 is connected via a buffer 8 to an anchor bolt 9 fixed to the ground. Between the wire rope 7 and the anchor bolt 9, a strain sensor unit 10 accommodating an FBG sensor for detecting distortion of the wire rope is attached. The strain sensor unit 10 and the strain measuring device 3 are connected by the optical fiber cable 2 for signal transmission. 4 is a processing unit. Reference numeral 5 denotes an alarm device for notifying danger, and reference numeral 6 denotes a warning display device.

In the avalanche information management system configured as described above, when an avalanche occurs, the impact force can be absorbed by the slip movement of the wire rope 7 by the shock absorber 8, and the wire rope 7 is cut. Also, pulling out of the anchor bolt 9 can be suppressed. The distortion of the wire rope 7 caused by the occurrence of the avalanche is detected by the distortion sensor unit 10, and the detected value is converted into the amount of distortion by the distortion measuring device 3. It is determined whether or not a warning has occurred.
Or activate the warning display device 6 installed on the road,
The avalanche occurrence information is reported promptly to prevent accidents due to avalanches.

[0030]

Third Embodiment (Traffic Accident Information Management System) FIG. 9 is a diagram for explaining a third embodiment, and shows a configuration in which the present invention is applied to a traffic accident information management system. Wire rope 7
And connect the end of the wire rope to the support 20 via the shock absorber 8.
It is connected to. A strain sensor unit 10 containing an FBG sensor for detecting the strain of the wire rope is attached to an appropriate number of places of the wire rope 7. The strain sensor unit 10 and the strain measuring device 3 are connected by the optical fiber cable 2 for signal transmission. 4 is a processing unit, 5 is an alarm device for notifying danger, and 6 is a warning display device.

With the accident information management system configured as described above, when the automobile 21 or the like collides with the wire rope 7 due to a traffic accident, the impact force is absorbed by the slip movement of the wire rope 7 by the shock absorber 8. Thus, cutting and pulling out of the wire rope 7 can be suppressed. The distortion of the wire rope 7 is detected by the distortion sensor unit 10, the detected value is converted into a distortion amount by the distortion measuring device 3, and the processing unit 4 determines which part and how much accident has occurred. In case of danger, the alarm device 5
By activating the warning display device 6 and the like installed on the road, the status of the accident is reported, the accident is prevented from expanding, and the accident can be dealt with promptly.

FIG. 10 is a view showing one embodiment of the mounting structure of the strain sensor section 10, and is applicable to the first to third embodiments. F
The BG sensor 17 (including a case having both a strain sensor and a temperature sensor) is mounted in the storage container 18 and the storage container 1
Reference numeral 8 is attached to the wire rope 7 using a fastening device 19. The FBG sensor 17 is connected to the strain measuring device 3 by a signal transmission optical fiber cable 2.

FIG. 11 is a view showing another embodiment of the mounting structure of the strain sensor section 10, and is applicable to the first to third embodiments. The FBG sensor 17 is mounted inside the storage container 18,
The storage container 18 is connected between the wire ropes 7, and has a structure in which the storage container 18 directly receives the tension received by the wire rope 7. As described above, the strain sensor unit 10 of the present invention can be configured to be attached to the wire rope 7 with the fastening tool 19 or to be connected between the wire ropes 7.

FIG. 12 is a diagram for explaining an example of a method for detecting an abnormality of a detection signal, and a graph shows a temporal change of the distortion amount. When the amount of change in distortion per unit time exceeds the threshold value, the distortion measuring device 3 determines that there is an abnormality. ○
Indicated by the mark.

FIG. 13 is a diagram for explaining another example of a method for detecting an abnormality of a detection signal, and a graph shows a temporal change of a distortion amount. When the distortion amount exceeds the threshold value, the distortion measuring device 3 determines that there is an abnormality. Needless to say, a discrimination method combining these two methods can be adopted according to the application.

In the embodiment described above, a wire rope having an energy absorbing mechanism is used.
Of course, it is possible to detect the amount of distortion of a normal wire rope. However, it is needless to say that the wire rope should not be easily broken in order to improve the reliability of the system.

[0037]

According to the present invention, the distortion of the disaster prevention wire net can be detected with high sensitivity by the FBG sensor, and a predetermined notification and warning can be promptly taken to take measures to prevent the occurrence of an accident. In addition, by adopting a wire rope with a shock absorber connected to the wire rope for disaster prevention, it absorbs the impact on the wire rope, prevents the wire rope from being cut and the anchor bolt from coming off, and the reliability of the defense management system It is an improvement.

Further, since the FBG sensor can detect the amount of dynamic strain on the order of microstrain, there is an advantage that the operation state of the energy absorbing mechanism of the wire rope can be instantaneously detected. Further, the FBG sensor has high sensitivity and a long signal transmission distance, and does not need to be relayed wirelessly. Therefore, as described in this embodiment, the combination of the energy absorption mechanism of the wire rope and the FBG sensor is extremely effective.

As described above, according to the present invention, it is not affected by induced electromagnetic noise or lightning, the construction of a monitoring system is inexpensive, maintenance and management are easy, malfunctions can be prevented, and wiring processing is easy. In addition, it is possible to provide a defense management system with high detection sensitivity capable of detecting dynamic fluctuation.

[Brief description of the drawings]

FIG. 1 is a diagram showing a first embodiment of a defense management system according to the present invention.

FIG. 2 is a view showing a configuration of a rock fall prevention wire net.

FIG. 3 is a view showing a mounting state of the shock absorber 8;

FIG. 4 is a view showing a configuration of a shock absorber 8;

FIG. 5 is a diagram showing a configuration of an FBG sensor for distortion measurement.

FIG. 6 is a diagram showing a configuration of a temperature compensating FBG sensor.

FIG. 7 is a diagram showing a state of wire rope distortion when a falling rock occurs.

FIG. 8 is a diagram showing a second embodiment of the control system according to the present invention.

FIG. 9 is a diagram showing a third embodiment of the defense management system according to the present invention.

FIG. 10 is a diagram illustrating a configuration example of a sensor mounting portion.

FIG. 11 is a diagram showing another example of the configuration of the sensor mounting portion.

FIG. 12 is a diagram illustrating an example of a detection signal abnormality detection method.

FIG. 13 is a diagram showing another example of a detection signal abnormality detection method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Rock fall prevention wire net 2 Optical fiber cable 3 Strain measuring device 4 Processing part 5 Alarm device 6 Warning display device 7 Wire rope 8, 12 Shock absorber 9 Anchor bolt 10 Strain sensor unit 11 Stopper 13 Detection element unit 14 Substrate 15 Adhesive 16 Avalanche prevention fence 17 Fiber grating type optical fiber sensor 18 Storage container 19 Fastening device 20 Prop 21 Automobile 22 Upper half of shock absorber 8 Lower half of shock absorber 8 24 Groove 25 Stopper 26 Hole 27 Bolt 28 Nut

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[Procedure amendment]

[Submission date] September 3, 1999 (1999.9.3)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claims

[Correction method] Change

[Correction contents]

[Claims]

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0010

[Correction method] Change

[Correction contents]

Further, a plurality of wire ropes are stretched vertically and horizontally, and the vertical wire ropes and the horizontal wire ropes are sandwiched and connected by a crossing buffer at a crossing portion, and a certain force or more is applied to the crossing portion. In this case, it is possible to adopt a configuration in which the crossing buffering device moves along a vertical wire rope or a horizontal wire rope and performs a buffering action in a state where the crossing buffering device keeps a constant holding force.

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] 0019

[Correction method] Change

[Correction contents]

Further, the vertical wire rope and the horizontal wire rope are sandwiched and connected by a crossing buffer 12 at a crossing portion. When a certain force or more is applied between these wire ropes and the crossing buffer 12 at the crossing portion, the crossing buffer 12 keeps a constant clamping force, and the vertical wire rope or the horizontal wire It is structured to move along the rope to provide a buffering action. For example, when a certain force or more is applied in the upper right direction to the crossover shock absorber 12 at an arbitrary position in FIG. 2, the crossover shock absorber 12 moves upward along the vertical wire rope and onto the horizontal wire rope. Move right along. The crossover buffer 12 can be realized, for example, by connecting two buffers 8 orthogonally.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] Explanation of sign

[Correction method] Change

[Correction contents]

[Explanation of Signs] 1 Rockfall prevention wire net 2 Optical fiber cable 3 Strain measuring device 4 Processing unit 5 Alarm device 6 Warning display device 7 Wire rope 8 Shock absorber 9 Anchor bolt 10 Strain sensor unit 11 Stopper 12 Crossover shock absorber 13 Detection Element part 14 Substrate 15 Adhesive 16 Avalanche prevention fence 17 Fiber grating type optical fiber sensor 18 Storage container 19 Fastening device 20 Post 21 Automobile 22 Upper half of shock absorber 8 23 Lower half of shock absorber 8 24 Groove 25 Stop fitting 26 Hole 27 Bolt 28 Nut

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hideo Teruya 1-3-1 Gotenyama, Musashino-shi, Tokyo NTT Advanced Technology Co., Ltd. (72) Inventor Eiichi Sugai Gotenyama, Musashino-shi, Tokyo 1-3-1 NTT Advanced Technology Co., Ltd. (72) Inventor Toshio Kubota 3-14-13 Toriyano, Niigata City, Niigata Prefecture F-term in Civil Co., Ltd. 2F065 AA65 BB12 CC00 DD04 DD11 EE02 FF41 LL02 SS09 2F076 BA01 BA12 BA15 BB08 BD06 BD07 BE05 BE12 BE15 BE17 5C086 AA12 AA14 AA45 AA46 AA54 BA11 BA13 BA22 CA01 CA24 CB18 CB33 CB35 CB40 DA01 DA14 DA15 DA18 DA23 DA11 FA26 GA29

Claims (8)

[Claims] 1. A strain sensor unit using a fiber grating type optical fiber sensor attached to the surface of a wire rope for detecting a strain of a wire rope stretched for disaster prevention, and reporting a danger based on the detection result. A defense management system characterized by: 2. Distortion of a wire rope stretched for disaster prevention is detected by a strain sensor unit using a fiber grating type optical fiber sensor connected between the wire ropes, and a danger is reported based on the detection result. A defense management system characterized by: 3. A single or plural wire rope stretched for disaster prevention, a strain sensor using a fiber grating type optical fiber sensor for detecting distortion of the wire rope, and the fiber grating type optical fiber A strain measuring device for detecting the magnitude of the strain generated in the sensor by using the characteristic of changing the Bragg wavelength, an optical fiber cable for signal transmission connecting between the strain sensor portion and the strain measuring device, A defense management system, comprising: a processing unit that performs a predetermined process based on a signal from a distortion measuring device; and an alarm unit that reports a danger based on a signal sent from the processing unit. 4. A buffer between the wire rope and the anchor bolt, which absorbs energy through extension of the wire rope when a predetermined tension or more is applied to the wire rope. The defense management system according to claim 1, wherein: 5. A plurality of wire ropes are stretched vertically and horizontally, and the vertical wire ropes and the horizontal wire ropes are sandwiched and connected by a buffer at an intersection, and when a certain force or more is applied to the intersection. 4. The device according to claim 1, wherein the buffering device is configured to move along a vertical wire rope or a horizontal wire rope so as to perform a buffering operation while maintaining a constant holding force. The described defense management system. 6. The defense management system according to claim 1, wherein a plurality of strain sensor units are used in series or in parallel to detect a strain on a wire rope at a plurality of locations. 7. A strain sensor section, wherein an optical fiber sensor for temperature compensation is installed in the vicinity of the optical fiber sensor for strain detection, an ambient temperature of the strain sensor section is detected, and a temperature change of the strain sensor section is detected. 7. The defense management system according to claim 1, wherein the detection value fluctuation due to the compensation is compensated. 8. The defense management system according to claim 1, wherein a danger is notified when the detected amount of distortion or the amount of change per unit time of the distortion exceeds a predetermined value.