JPH0731753B2 - Tunnel abnormality notification device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for reporting an abnormality in a tunnel, and more specifically, an optical fiber is installed in a tunnel to transmit an optical pulse, and the optical fiber has a plurality of predetermined portions. The present invention relates to a device for reporting an abnormality in a tunnel, in which a sensor that causes a transmission loss is arranged, photoelectrically converts returned light of an optical pulse that has been sent out, and then arithmetic processing is performed to detect the abnormality and further report the abnormality.

[Conventional technology]

A conventional device for reporting an abnormality in a tunnel, for example, a device for reporting a fire in a tunnel, lays a metal conductor transmission line in the tunnel to perform signal transmission, uses a thermocouple type sensor as a sensor, and is a sensor generated by a temperature rise due to a fire. After amplifying the thermoelectromotive force of the above, it is transmitted to the signal processing device provided in the management center, etc. via the above transmission path, the fire is detected based on the received signal, and the fire department is notified. It was

Therefore, to the drivers of various vehicles passing through the tunnel, and to the pedestrians in the tunnel where pedestrians can also pass (hereinafter referred to as tunnel passers including drivers and pedestrians of the various vehicles) There was no means to report a fire.

[Problems to be solved by the invention]

With the conventional fire alarm system in the tunnel as described above, the focus was placed on the occurrence of a fire, warning and extinguishment, so be careful to prevent the evacuation guidance and rescue of the victims and the subsequent secondary disaster. I've never been told.

Therefore, if a fire occurs in the tunnel, another vehicle that enters the tunnel without knowing that the fire has spread and is unable to move because of a rear-end collision, collision with the side wall of the tunnel, or a following vehicle. In addition, the secondary disaster caused more damage, such as human damage caused by the generated gas. Moreover, the presence of this intruding vehicle hindered fire extinguishing and rescue operations.

Further, in the conventional device, the metal transmission line is used for signal transmission, the humidity is high in the tunnel, and shortage and malfunction are likely to occur, and there is a risk of electric shock due to water discharge during a fire. Since the thermocouple type sensor generates a small amount of voltage and electric power, it is not possible to transmit over a long distance with the electromotive voltage as it is, and it is common to use an amplifier to amplify and cover the voltage drop of the transmission line.

Furthermore, since a metal transmission line is used, malfunctions due to mixing of stray current and electromagnetic induction noise, erroneous detection, and the judgment unit and
The reliability of the A / D converter reference voltage fluctuations and insulation defects was low.

The present invention has been made to solve such a problem, and provides an in-tunnel abnormality notification device capable of preventing the occurrence of a secondary disaster by detecting an abnormality in a tunnel and further reporting the abnormality. With the goal.

[Means for Solving Problems] In order to achieve such an object, an in-tunnel anomaly notification device according to the present invention is provided with an optical fiber laid in a tunnel and a plurality of predetermined parts of the optical fiber. In the normal state below the predetermined temperature, while forming a coil shape,
A shape memory alloy sensor that gives a microbend to the optical fiber to generate a transmission loss by deforming linearly at the time of an abnormality above a predetermined temperature, a light emitting means for sending an optical pulse to the optical fiber, and this light emitting means A photoelectric conversion unit that photoelectrically converts the returned light of the sent light pulse, and the output signals from the photoelectric conversion unit are averaged to obtain the intensity waveform β of the Rayleigh scattered light, and the Rayleigh scattered light in a normal state. The difference with the reference intensity waveform α is taken, and the distance derivative of this difference (α-β) is calculated.
An abnormality detection unit that detects an abnormality occurrence and an abnormality occurrence position in the tunnel based on the differentiation result, and an abnormality notification unit that notifies the tunnel passer of the occurrence of the abnormality based on an output signal of the abnormality detection unit. It is characterized by having.

[Operation] In this generation, an optical fiber is laid in a tunnel, sensors that generate a transmission loss are arranged in a plurality of predetermined portions of the optical fiber, and the return light of the optical pulse sent to the optical fiber is photoelectrically converted, and then the calculation is performed. Since it processes and detects anomaly and notifies the tunnel passer of the fire occurrence, that is, when a fire occurrence is detected, the traffic signal is changed from blue to red via yellow by the output signal of the above detection means. Since the vehicle is forcibly stopped, characters are displayed to indicate that a fire has occurred, and evacuation guidance is displayed, secondary disasters are prevented, and optical signals are used on the transmission line using optical fibers. High reliability is obtained because of the transmission.

Further, in the present invention, the coil shape before deformation, a sensor made of a shape memory alloy that becomes linear at a predetermined temperature or higher is wound around a plurality of predetermined portions of the optical fiber to fix both ends of the sensor to the optical fiber. When the sensor made of the shape memory alloy is linearly deformed when rising, the optical fiber is twisted back and bent at a small bending rate, and the loss of the backward Rayleigh scattered light is surely increased.

Moreover, in the present invention, the intensity waveform is obtained by averaging the weak Rayleigh scattered light, and a reference intensity waveform in a normal state (a state in which the optical fiber does not have a microbend) is obtained, and the difference between the two is calculated. Since the temperature anomaly is detected by differentiating this by the distance, it is possible to reliably specify each occurrence position with high reliability and even if the anomalies occur at two or more locations at the same time.

[Embodiment] FIG. 1 is a conceptual diagram showing an embodiment of the present invention. First
In the figure, 1 is a tunnel, 2 is a road, and 4 is a tunnel 1.
It is an optical fiber laid inside. Reference numeral 5 is a shape memory alloy sensor which causes transmission loss in the optical fiber, and has a structure shown in FIG. That is, when the temperature of the shape memory alloy coil 5 rises above a preset temperature, it is deformed into a linear shape 5'like 5'and the optical fiber 4 is twisted in the opposite direction to form a coiled optical fiber 4 ', resulting in optical transmission loss. Is generated. In the case of a tunnel fire, flammable materials such as gasoline in the car are present, and the ventilation for the tunnel is frustrating, and the flame becomes over 1000 degrees. Since this high-temperature airflow rises above the tunnel, this fire detection sensor 5 is also installed on the ceiling. The preset fire detection temperature is set to 55 ° to 110 ° so that it does not malfunction due to air temperature or exhaust temperature.

A traffic signal 7 is installed inside and outside the tunnel at predetermined intervals. 8 is a fire occurrence site, 9 is an accident vehicle, 11 is a character display panel, 12 is a speed limit display panel, and 13 is an evacuation guidance display panel.

Reference numeral 20 denotes a signal processing device, which is installed on the side of the road and emits light pulses to the optical fiber 4, a photoelectric conversion device for photoelectrically converting the return light from the optical fiber 4, and an arithmetic processing of the photoelectrically converted signal. An abnormality detecting means for detecting an abnormality (fire) is included, an optical pulse is sent to the optical fiber 4, a fire is detected by a change in the returning light, and an abnormality detection signal including fire occurrence position data is output.

With the above configuration, a fire 8 occurred in the tunnel 1,
When the sensor 5 is deformed due to the temperature rise, a transmission loss occurs in the optical fiber 4, the return light received by the signal processing device 20 changes, and a fire is detected. Next, the operation of the signal processing device 20 will be described.

FIG. 3 is a waveform diagram in a normal state for explaining the principle of the operation of the signal processing device 20. In FIG. 3, the horizontal axis indicates the distance L (m) from the light emitting means on the optical fiber, and the vertical axis indicates the intensity I _R of the return light returned from the optical fiber by the light pulse from the light emitting means in dB. It is shown. This waveform α emits pulsed light from one end of the optical fiber 4, and the light intensity of the weak Rayleigh scattered light back-scattered by the scattering source such as the dopant in the core uniformly distributed in the optical fiber 4 changes with time. This is the recorded waveform.

The backscattered light is very weak compared to the transmitted pulse (eg -46
dB) so S / N is bad. Therefore, time averaging, etc. is performed to improve the sensitivity for measurement. Since the backscattered light intensity is proportional to the light intensity at that position, if it is far from the end face of the optical fiber, there is a round trip effect of attenuation (due to the filter action) for the light to propagate up to that distance. Since the time required for the round trip is directly proportional, the light intensity (dB) of the light receiver is plotted on the vertical axis, and the time is plotted on the horizontal axis, which is a straight line α descending to the right. Note that the distance L can be expressed by the distance L = c / n ₁ · t in consideration of the refractive index n ₁ of the core of the optical fiber 4.

In this way, the normal waveform is the straight line α to the right. here,
This slope is the transmission loss per unit length of the optical fiber. The waveform α in the normal state is not a perfect straight line due to nonuniformity of the refractive index at the time of manufacturing the optical fiber, microbends at the time of laying, etc., but is stable in time,
It is a function of distance. This waveform α is a reference waveform.

FIG. 4 is a waveform diagram at the time of abnormality for explaining the principle of operation of the signal processing device 20. Similar to Fig. 3, the horizontal axis is distance L
( _M ), the vertical axis represents the intensity I'R (dB) of the returning light. β ° is a waveform at the time of abnormality. x indicates the position where the abnormality has occurred. Further, ζ is generated due to the time constant of the photomultiplier tube in the light receiving element or the case where the pulse width is large, but cannot be completely zero.

FIG. 5 is an explanatory view for explaining the principle of detecting one abnormality, and FIG. 5 (a) shows an abnormal waveform β and a reference waveform α with a dotted line. The figure (b) shows the difference waveform of α-β, and η ′
Is a threshold function. This threshold function η ′ has a large loss near the light emitting point and a low loss at a distant point even if the same optical fiber is deformed. Therefore, the threshold decreases monotonically as the distance increases. It is as a function. (C) is a distance differential waveform of ΔI _R that is α-β. When an abnormality occurs at L ₀ point as shown in FIG.
Calculating a-beta, it may determine an abnormality in comparison with a threshold value, since in practice the rounded waveform as the described above dashed zeta, obliquely at L ₀ point as shown in (b) FIG. It has a rising waveform.

On the other hand, the lower the threshold, the better the sensitivity, but the higher the probability of malfunction. Considering this, the threshold value should be as high as possible. However, if the threshold value is increased, an error indicated by A occurs at the abnormal position L ₀ . Then α
If a distance differential waveform of I _R that is −β is created, it becomes as shown in Fig. (C), and a waveform that rises in a substantially straight line can be obtained at L ₀ , and x ₀ is obtained as the intersection of η and δ on the light source side. Therefore, the abnormality occurrence position L ₀ can be accurately detected.

FIG. 6 is an explanatory view for explaining the principle of detecting anomalies at two locations. FIG. 6 (a) shows an abnormal waveform β ′ when abnormalities occur simultaneously at two points L ₁ and L ₂ , and FIG. 6 (b). The figure shows the difference waveform γ'of α-β 'corresponding to FIG. 5 (b). In this case, α-β '
Even if the difference is calculated, the abnormality at L ₂ cannot be detected. However, L ₁ and L ₂ can be detected separately by the intersection points x ₁ and x ₂ by creating a distance differential waveform of the α-β ′ difference waveform shown in FIG.

Next, the configuration of the signal processing device 20 will be described. FIG. 7 is a block diagram showing an example of the configuration of the signal processing device 20. In FIG. 7, 4 is an optical fiber, and 5 is a sensor made of a shape memory alloy. An electro-optical conversion element 51 is a light emitting means such as a laser diode or a photo diode. A pulse oscillator 52 excites the light emitting means 51 to generate an optical pulse. 53 is a directional coupler, 54 is a synchronizing signal generator, 55 is a photoelectric conversion element, 56 is a logarithmic analog digital (hereinafter abbreviated as A / D) converter, 57 is a CRT as a display device, 58 is an amplifier, 60 is a buffer memory for storing the received light data waveform ε corresponding to the 1-pulse sweep screen, 61 is 1
Memory for batch data, 62 is a reference waveform α creating circuit, 63 is a moving n times update data for discrimination β ′ creating circuit, 64 is a difference circuit,
Reference numeral 65 is a distance differentiating circuit, 66 is a threshold function data η generating circuit, 67 is a comparing / determining circuit, and 68 is a distance data output circuit.

Next, the operation will be described using the flow chart shown in FIGS. 7 and 8. Turn on the device (step 60
1), the light emitting means 51 sends an optical pulse to the optical fiber 4. The return light of the optical pulse transmitted to the optical fiber 4 is input to the photoelectric conversion element 55 via the directional coupler 53, and its output is synchronized with the optical pulse by the A / D converter 56 and is A
/ D converted. On the other hand, the sweep screen with one pulse is CR
Displayed on T57. Further, the light reception data corresponding to the sweep screen by one pulse is stored in the buffer memory 60.

In the present invention, the sweep screen with one pulse is called a single screen ε. Then, first, the reference waveform data α is created by performing the initial m times of time averaging before the occurrence of abnormality. The reference waveform data α is created by the reference waveform data creation circuit 62 (steps 602 and 603).

On the other hand, the moving data for discrimination n times updated β'is the average value of the latest single screen ε, that is, if the average of n pieces is the latest data, 1 / n is added to add the oldest data (n + 1 times before). Data) is obtained by subtracting 1 / n and is constantly updated. Discrimination movement n times updated waveform data β'is created by the discrimination movement n times updated waveform data β'creation circuit 63 (steps 604 and 605). Waveform data α
And the waveform data β'are input to the difference circuit 64 to calculate the difference waveform data γ '(step 606).

Next, the waveform data .delta. 'Of the differential value in the distance direction is created by the distance differentiating circuit 65 (step 607). The threshold value η is set in advance by a generator circuit 66 as a function waveform falling at a distance, and a judgment circuit 67 judges whether or not the waveform data δ ′ exceeds a threshold value (steps 608 and 609). If δ '> 0, it is normal and the process returns to step 605. If .eta .-. delta. '<0, it is abnormal and the abnormality detection signal output from the determination circuit 67 is measured by the distance data output circuit 68 for the value of the abnormality occurrence distance L (step 610). Output as control signal 694 for 71 (step 611)
Return to 605.

Further, the distance data output is transmitted to the management center 31 and the fire department 32 in order to generate the fire alarm 691 and display and record the distance data 692 and the occurrence time 693. Further, at the same time as displaying the waveform 695 shown in FIGS. 5 and 6, the cursor generating circuit 70 is operated to display the cursor at the position of the distance data.

As another method of creating the reference waveform data α, a moving average for a certain period of time is used. This is to determine whether an abnormality has occurred at regular intervals.When no abnormality has occurred, the infinite average waveform up to the latest on the single screen is used as the reference waveform data, and when an abnormality has occurred, the time moving average calculation is performed. Stop,
The previous value is used as the reference waveform data α. That is, the reference waveform data α is updated until an abnormality occurs, and when the abnormality occurs, the updating is stopped. By doing so, the best reference waveform can be obtained. The updating of the reference waveform data α is stopped by inputting the abnormality detection signal of the comparison / determination circuit 67 to the reference waveform data α creation circuit 62 (see the broken line in FIG. 7).

The signal processor 20 is an optical fiber 4 installed in the tunnel 1.
Although it may be installed at one end of the tunnel 1, it is installed at both entrances of the tunnel 1 as shown in FIG. 1, and normally one of the signal processing devices is operated to detect a fire. When the optical fiber 4 is melted by one fire, both signal processing devices are operated, so that even if the optical fiber 4 is melted in the middle of the tunnel, the fire detection and the notification operation can be performed without any trouble.

Next, the abnormality detection signal of the signal processing device 20 is the traffic signal 7, character display panel 11, speed limit display panel 12, which is an abnormality reporting means,
It is input to a control circuit (not shown) of the evacuation guidance display panel 13 and a pedestrian in the tunnel is notified of a fire.

The details of the abnormality reporting means will be described below.

First, the abnormality detection signal is input to the control circuit of the traffic signal 7, and the blue signal is shifted in time from a place near the fire occurrence site 8 in order, then changed to red via yellow to force the vehicle. To stop. The reason the traffic signal 7 is changed in the order of blue → yellow → red is to prevent the driver from suddenly braking and causing a rear-end collision.

To which side of the front of the tunnel the red light should be turned on is determined by considering the traffic volume on the road when a fire occurs. Even if the tunnel is not dedicated to going up and down but travels in both directions, stop signals will be given for both up and down directions.

Since it is not practical to transmit blue, yellow, and red of a traffic light by light, a known traffic light is used, and a control signal is transmitted using a metal transmission path.

Next, characters such as "fire occurred" are displayed on the character display panel 11 provided at the entrance of the tunnel 1 to the tunnel passers,
Report that there is a fire in the tunnel.

The speed limit display 12 installed beside the road
If 100km is displayed, change the display to 40km to slow down the speed of the vehicle so that the total amount of vehicle moving in the direction of the tunnel 1 where the fire is occurring is reduced. The speed limit is changed at a distance far ahead of the tunnel 1.

Inside the tunnel, there is a sketch of the tunnel, a display of the current position and how many meters ahead of it there is a fire, and an evacuation guidance display panel 13 that indicates in which direction you should evacuate.
Are installed at several places at fixed distances, and a display is displayed by the output of the signal processing circuit 20 to indicate the evacuation direction of the tunnel passerby. The evacuation guidance display panel should be installed below the tunnel 1 in order to minimize the effect of smoke caused by fire.

Where there are separate tunnels for going up and down, for example, when there is a fire near the exit of tunnel 1 or in the up lane, if there is a route to go down the lane, give instructions to evacuate by going down and You can also evacuate by turning off the traffic lights in the lanes to stop traffic.

It is also possible to give an instruction from the detour display panel 16 near the inter-engineer 15 to "leave this inter-engineer because a fire has started in the front tunnel."

If there is a facility for radio broadcasting in the tunnel, it is possible to broadcast the fire occurrence on the radio by the output of the signal processing circuit 20.

FIG. 9 shows another example of the sensor 5, which is a pipe-shaped shape memory alloy sensor 5. When the temperature exceeds a preset temperature, the waveform is deformed like 5'and the optical fiber 4 is accompanied by this. Also transforms the waveform.

FIG. 10 shows still another example of the sensor, which operates as the emergency notification push button 5a.

Reference numerals 101 and 102 denote a pair of plate-shaped members having a corrugated surface. One plate-shaped member 101 is fixed, while the optical fiber 4 is sandwiched between the plate-shaped members 101 and 102, and usually the three members are in contact with each other or not in contact with each other. And the other plate-shaped body 102 is arranged. Reference numeral 103 denotes a push button, and when the push button 103 is pushed, the plate-like body 102 is also pushed, so that the optical fiber 4 is supported by the microbend. The push button 103 is structured to be locked in the above state.

As shown in FIG. 1, the emergency notification push button 5a is installed in series in the tunnel in series with the sensor 5 and at a height that a person can reach. Therefore, for example, the driver of the accident vehicle 9 can push the nearby push button 5a to notify the management center 31 of the accident before the fire occurs and even when the fire does not occur.

In addition, a microphone and a speaker are installed near the emergency notification push button 5a for communication between passers-by and managers (management center staff), and a TV camera, etc. is installed for monitoring inside the tunnel. It is possible to help prevent secondary disasters by transmitting information using communication. Fig. 11 shows another example of laying the optical fiber 4, in which several independent optical fibers are installed in parallel in the tunnel. It is installed and detected at both ends.

FIG. 12 shows still another example of the installation of the optical fiber 4, 1
The optical fiber 4 of the book is laid in a zigzag manner while covering a large area.

FIG. 13 shows an example laid in a loop shape. In this example, the end portions of the optical fiber 4 are connected by the same signal processing device, but the optical pulse is sent out from either end portion.

〔The invention's effect〕

As can be seen from the above description, according to the present invention, an abnormality such as a fire is detected, and since a tunnel passerby is notified of the fire occurrence, it is not necessary to enter the tunnel without knowing the fire occurrence, and evacuation guidance is also provided. It is effective and can prevent secondary disasters.

Further, the optical fiber side and the sensor side can be set to a non-power source, have no harm, have no inductive property, and have high insulation reliability and high reliability.

Further, in the present invention, the coil shape before deformation, the shape memory alloy sensor which becomes linear at a predetermined temperature or higher is wound around a plurality of predetermined portions of the optical fiber to fix both ends of the sensor to the optical fiber. Is easy to install, and the shape memory alloy sensor deforms linearly when the temperature rises, causing the optical fiber to be twisted back and bent at a small bending rate, which surely increases the loss of backward Rayleigh scattered light. . That is, when the temperature rises, only the sensor is not deformed or prevented from being deformed, and the abnormality is reliably detected.

Further, in the present invention, the weak Rayleigh scattered light is added and averaged to obtain an intensity waveform, and a reference intensity waveform in a normal state (a state where no microbend of the optical fiber is generated) is obtained, and a difference between the two is obtained. Since the temperature abnormality is detected by differentiating the distance, it is highly reliable, and even if the abnormality occurs at two or more locations at the same time, it is possible to reliably identify the respective generation positions. That is, since appropriate information can be notified to the tunnel passerby depending on the location of the abnormality, the secondary disaster can be reliably prevented.

[Brief description of drawings]

FIG. 1 is a conceptual diagram showing an embodiment of the present invention, FIG. 2 is a perspective view showing an example of a shape memory alloy sensor, and FIG. 3 is a normal state for explaining the operation principle of a signal processing device. Waveform diagram, FIG. 4 is a waveform diagram at the time of abnormality for explaining the principle of the operation of the signal processing device, and FIG. 5 is an explanatory diagram for explaining the principle of detecting one abnormality, and FIG. 5 (a) Is a waveform diagram showing an abnormal waveform β, FIG. 5 (b) is a waveform diagram showing a difference between α and β,
FIG. 5 (c) is a waveform diagram showing the distance differentiation of α-β, FIG. 6 is an explanatory diagram of the principle of detecting abnormality at two places, and FIG. 6 (a) is a waveform diagram showing the abnormal waveform β ′. , FIG. 6 (b) shows α
FIG. 6 (c) is a waveform diagram showing the distance differentiation of α-β ′, FIG. 7 is a configuration diagram showing an example of the configuration of the signal processing device, and FIG. 8 is a signal diagram. A flow chart showing the operation of the processing apparatus, FIG. 9 is a perspective view showing another example of the shape memory alloy sensor, FIG. 10 is a conceptual view showing a push button for emergency notification, and FIG. 11 is a method of laying optical fibers. FIG. 12 is a conceptual diagram showing another example of the optical fiber laying method, and FIG. 13 is a conceptual diagram showing still another example of the optical fiber laying method. In the figure, 1: Tunnel, 2: Road, 4: Optical fiber, 5: Sensor, 7: Traffic signal, 8: Fire scene, 11: Character display, 1
2: Speed limit display panel, 13: Evacuation guidance display panel, 14: Detour display panel, 51: Light emitting means, 53: Directional coupler, 55: Photoelectric conversion element, 56: A / D converter, 60: Buffer memory.

Claims (1)

[Claims] 1. An optical fiber laid in a tunnel, and arranged in a plurality of predetermined portions of the optical fiber so as to form a coil shape when the temperature is lower than a predetermined temperature, and to be linearly deformed when the temperature exceeds a predetermined temperature. A shape memory alloy sensor that applies a microbend to the optical fiber to generate a transmission loss, a light emitting unit that sends out a light pulse to the optical fiber, and a photoelectric converter that photoelectrically converts the return light of the light pulse sent out from the light emitting unit. The conversion means and the output signals from the photoelectric conversion means are added and averaged to obtain the intensity waveform β of the Rayleigh scattered light, and a difference from the reference intensity waveform α of the Rayleigh scattered light in a normal state is calculated, and the difference is further calculated. Anomaly that detects the distance differentiation of (α-β) and detects the abnormality occurrence and the position where the abnormality occurs in the tunnel based on this differentiation result Means out, this abnormal tunnel abnormality notification apparatus characterized by comprising an abnormality notification means notifies the tunnel passerby occurrence of the abnormal based on the output signal of the detection means.