JP2011168980A - System and method for detecting abnormality in manhole - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To detect an omen of collapse of a manhole without a person's entry into the manhole. <P>SOLUTION: In this system 1 for detecting an abnormality in the manhole, when a top plate 200 receives pressure caused by a distortion as the omen of the collapse of the manhole, the pressure is transferred to a piezoelectric sensor 400. The piezoelectric sensor 400 outputs a signal to a radio tag 500 by detecting the pressure transferred from the top plate 200. When the signal is output from the piezoelectric sensor 400, the radio tag 500 transmits a radio signal. The reception of the radio signal on the ground enables the omen of the collapse of the manhole to be detected without the person's entry into the manhole. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a manhole abnormality detection system and a manhole abnormality detection method.

Stress is generated in each part of the manhole when an external force is applied to the manhole wall (especially a ceiling or a side wall) by soil or a vehicle. FIG. 15 is a diagram illustrating an example of a stress distribution with respect to an external force applied to the manhole. For example, when an external force v1 is applied to the manhole ceiling from above, a compressive stress v2 is generated on the upper side of the concrete on the ceiling, and a tensile stress v3 is generated on the lower side. Due to these stresses, the strength of the concrete deteriorates. If the strength of concrete progresses without renovating the manhole, the manhole will eventually collapse, for example, the ceiling of the manhole will collapse.
One of the methods for estimating the strength of concrete is an estimation method using a Schmitt hammer, which is also applied to manhole diagnosis. According to the estimation method using a Schmitt hammer, the compressive strength of concrete can be estimated nondestructively. In this method, a weight is caused to collide with a concrete surface via a steel rod, the amount of rebound of the weight at the time of collision is measured, and the compressive strength is estimated based on the measured amount of rebound. When diagnosing a manhole using a Schmitt hammer, a maintenance inspector enters the manhole and measures the amount of repulsion by colliding the Schmitt hammer against the ceiling of the manhole. Manhole strength diagnosis can be performed by estimating the compressive strength (tensile stress) of concrete from the measured amount of rebound (see Non-Patent Document 1 and Non-Patent Document 2).

Chubu Electric Power, “Technology Development News (No. 121) Special Feature: Development of diagnostic technology for underground transmission and distribution facilities”, July 2006, http://www.chuden.co.jp/torikumi/study/library/news/pdf/ list121 / N12105.pdf Chubu Electric Power, “Technology Development News (No. 104) Research Results Development of Strength Diagnosis Method for Aged Manholes”, September 2003, http://www.chuden.co.jp/torikumi/study/library/news/pdf/ list104 / N10419.pdf

  However, it is often not easy for an inspection worker to enter a manhole in order to diagnose a manhole using a Schmitt hammer. For example, manholes are often flooded (flooded), and drainage is required for workers to enter. For this drainage work, it is necessary to prepare drainage equipment such as a drainage pump and a power generation device for securing the power supply. Also, the drainage work itself often takes half a day or a day. In addition, since manholes are usually provided on roads, it is necessary to report work to the police and to control traffic on the roads that are being worked on, and to secure personnel for traffic control. Due to such burdens and costs of preparation and work, the interval between inspections tends to be long, and the risk of manhole collapse during that period increases. In order to eliminate the danger of manhole collapse, it is possible to renovate or re-install the manhole, but civil engineering work is required, so it costs 10 to 100 times more than inspection. . In order to reduce costs, it is desirable to regularly check with a cheaper inspection method to grasp the signs of the manhole collapse and to make the manhole usable as long as possible without renovation.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a manhole abnormality detection system and a manhole abnormality detection method capable of detecting a sign of manhole collapse without a person entering the manhole. There is.

  [1] The present invention has been made to solve the above-described problems. A manhole abnormality detection system according to an aspect of the present invention is installed along a wall of a manhole, and changes in pressure from the wall of the manhole. A distortion detecting unit that detects distortion of the wall of the manhole, and a transmission unit that transmits a signal indicating that the distortion is detected when the distortion detecting unit detects distortion of the wall of the manhole. It is characterized by that.

  [2] A manhole abnormality detection system according to an aspect of the present invention is the above-described manhole abnormality detection system, wherein the wall of the manhole is a ceiling of the manhole having a rectangular shape, and the distortion detection unit includes: The shape and size excluding the entrance / exit portion of the manhole from the shape and size corresponding to two triangles obtained by dividing the rectangle of the ceiling of the manhole into two diagonal lines, and along the ceiling of the manhole From the ceiling of the manhole received by the top plate, the plurality of top plates to be installed, the plurality of columns supporting each of the plurality of top plates from below, and the top plate and the columns. A piezoelectric sensor for detecting pressure, and each of the top plates is supported from below at three points by three support columns, and the piezoelectric sensor is Located between the strut and the top plate at any one point of the three-point plate is supported, the transmission unit is characterized by a radio tag for transmitting a radio signal.

  [3] A manhole abnormality detection system according to an aspect of the present invention is the manhole abnormality detection system described above, wherein the wall of the manhole is a ceiling of the manhole, and the distortion detection unit is a ceiling of the manhole. The shape and size, excluding the entrance and exit portion of the manhole, has a shape and size, a top plate installed along the ceiling of the manhole, a plurality of support columns that support the top plate from below, A piezoelectric sensor that is installed between each of the columns and the top plate and that detects pressure from the ceiling of the manhole received by the top plate, and the transmission unit is a wireless tag that transmits a wireless signal It is characterized by being.

  [4] A manhole abnormality detection system according to an embodiment of the present invention is the above-described manhole abnormality detection system, wherein the top plate is attached to the frame supported by the column, the frame, And a plurality of unevenness adjusting bolts whose lengths from the frame are adjusted so as to come into contact with the ceiling.

  [5] A manhole abnormality detection system according to an embodiment of the present invention is the above-described manhole abnormality detection system, wherein the top plate is supported by the support column having a variable length, and the frame. A plurality of concavo-convex adjustment bolts attached and adjusted in length from the frame, and supported from below by the concavo-convex adjustment bolts, and depending on the length of the concavo-convex adjustment bolts from the frame, on the ceiling of the manhole And a plurality of top panel panels installed at the height and direction of contact.

  [6] A manhole abnormality detection system according to an aspect of the present invention is the manhole abnormality detection system described above, wherein the wall of the manhole is a side wall of the manhole, and the strain detection unit is a side wall of the manhole. A side plate installed along the side wall of the manhole, a plurality of columns supporting the side plate from a lateral direction, a beam for fixing the position of the column, the column and the column And a piezoelectric sensor that detects a pressure from a side wall of the manhole received by the side plate, and the transmission unit is a wireless tag that transmits a radio signal.

  [7] In the manhole abnormality detection method according to an aspect of the present invention, the strain detection unit installed along the manhole wall may be configured so that the distortion of the manhole wall is based on a change in pressure from the manhole wall. And a transmission step of transmitting a signal indicating that the distortion is detected when the distortion of the manhole wall is detected in the distortion detection step. To do.

  [8] A manhole abnormality detection method according to an aspect of the present invention is the above-described manhole abnormality detection method, wherein the wall of the manhole is a ceiling of the manhole having a rectangular shape, and the distortion detection unit includes: The shape and size excluding the entrance / exit portion of the manhole from the shape and size corresponding to two triangles obtained by dividing the rectangle of the ceiling of the manhole into two diagonal lines, and along the ceiling of the manhole From the ceiling of the manhole received by the top plate, the plurality of top plates to be installed, the plurality of columns supporting each of the plurality of top plates from below, and the top plate and the columns. A piezoelectric sensor for detecting pressure, and each of the top plates is supported from below by three supporting columns at three points, and the top plate supports each top plate. Is located between the strut and the top plate at any one point of the three points are, and the transmission unit, characterized in that it is a radio tag for transmitting a radio signal.

  [9] A manhole abnormality detection method according to an aspect of the present invention is the manhole abnormality detection method described above, wherein the wall of the manhole is a ceiling of the manhole, and the strain detection unit is a ceiling of the manhole. The shape and size, excluding the entrance and exit portion of the manhole, has a shape and size, a top plate installed along the ceiling of the manhole, a plurality of support columns that support the top plate from below, A piezoelectric sensor that is installed between each of the columns and the top plate and that detects pressure from the ceiling of the manhole received by the top plate, and the transmission unit is a wireless tag that transmits a wireless signal It is characterized by being.

  [10] A manhole abnormality detection method according to an embodiment of the present invention is the above-described manhole abnormality detection method, wherein the top plate is attached to the frame supported by the support column, and the manhole. And a plurality of unevenness adjusting bolts whose lengths from the frame are adjusted so as to come into contact with the ceiling.

  [11] A manhole abnormality detecting method according to an aspect of the present invention is the manhole abnormality detecting method described above, wherein the top plate is supported by the support column having a variable length, and the frame is attached to the frame. A plurality of concavo-convex adjustment bolts attached and adjusted in length from the frame, and supported from below by the concavo-convex adjustment bolts, and depending on the length of the concavo-convex adjustment bolts from the frame, on the ceiling of the manhole And a plurality of top panel panels installed at the height and direction of contact.

  [12] A manhole abnormality detection method according to an embodiment of the present invention is the above-described manhole abnormality detection method, wherein the manhole wall is the side wall of the manhole, and the strain detection unit is the side wall of the manhole. A side plate installed along the side wall of the manhole, a plurality of columns supporting the side plate from a lateral direction, a beam for fixing the position of the column, the column and the column And a piezoelectric sensor that detects a pressure from a side wall of the manhole received by the side plate, and the transmission unit is a wireless tag that transmits a radio signal.

  By detecting a sign that a manhole collapses using the present invention, a sign of a manhole collapse can be detected without a person entering the manhole.

It is a block diagram which shows schematic structure of the manhole abnormality detection system in the 1st Embodiment of this invention. In the same embodiment, it is a figure which shows the example of arrangement | positioning which uses 2 sets of manhole abnormality detection systems 1. FIG. It is a figure which shows another example of arrangement | positioning which uses 2 sets of manhole abnormality detection systems 1 in the embodiment. In the same embodiment, it is a figure which shows the example of the shake transmitted to the manhole 100 at the time of vehicle passage, and the shake by a collapse sign. It is a block diagram which shows schematic structure of the manhole abnormality detection system in the 2nd Embodiment of this invention. In the same embodiment, it is a figure which shows the example which covers the manhole of irregular shape with one top plate. It is a block diagram which shows schematic structure of the manhole abnormality detection system in the 3rd Embodiment of this invention. In the same embodiment, it is sectional drawing which looked at the top plate 205 installed so that a ceiling might be covered from the horizontal direction. In the same embodiment, it is a figure which shows the example which couple | bonded two support | pillar parts 310 using the height adjustment bolt 320. FIG. In the same embodiment, it is a figure which shows the example which inserted the piezoelectric sensor between the top panel and the uneven | corrugated adjustment bolt. In the same embodiment, it is a figure which shows the example which used the said top plate for the top plate comprised only with a trust frame, and the manhole 105 with an uneven | corrugated ceiling. In the same embodiment, it is a figure which shows the example which used the said top plate for the top plate of the trust frame to which the uneven | corrugated adjustment bolt 220 was attached, and the manhole 105 with an uneven | corrugated ceiling. It is a block diagram which shows schematic structure of the manhole abnormality detection system in the 4th Embodiment of this invention. It is a block diagram which shows schematic structure of the manhole abnormality detection system 8 in the 5th Embodiment of this invention. It is a figure which shows the example of the stress distribution with respect to the external force added to a manhole.

<First Embodiment>
Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a configuration diagram showing a schematic configuration of a manhole abnormality detection system according to the first embodiment of the present invention.
In the figure, a manhole 100 exists under a road, an entrance is provided from the manhole 100 toward the ground surface (road), and a ground surface portion of the entrance is covered. A pipe line is provided between the manhole 100 and another manhole, and a communication cable is passed through the pipe line. The manhole 100 is provided with a closure for connecting / branching a communication cable.
The manhole abnormality detection system 1 is built inside the manhole 100 and includes a top plate 200, a total of three columns 300 and 301, a piezoelectric sensor 400, and a wireless tag 500. Among these, the top plate 200, the support column 300, and the piezoelectric sensor 400 are combined to correspond to the strain detection unit. As described below, when the ceiling of the manhole is distorted, the top plate 200 is removed from the ceiling of the manhole. The pressure received by the piezoelectric sensor 400 increases, and the piezoelectric sensor 400 detects the distortion of the ceiling of the manhole based on the increase in pressure.

The manhole abnormality detection system 1 detects a distortion of the ceiling of the manhole 100 (deformation due to external pressure or the like) using the piezoelectric sensor 400 attached to the support column 300, thereby predicting the collapse of the target manhole 100. Detect.
The support column 301 is installed at a corner (a corner or a protruding portion) of the manhole 100 and supports the top plate 200. The support column 300 is installed at the corner of the manhole 100 and supports the top plate 200 similarly to the support column 301, but the support column 300 is shorter than the support column 301 by the thickness of the piezoelectric sensor 400, and between the support column 300 and the top plate 200. The piezoelectric sensor 400 is inserted in
The top plate 200 is generated using a material that is not easily deformed, such as steel, and covers a part of the ceiling of the manhole 100 supported by the columns 300 and 301.
The piezoelectric sensor 400 outputs a signal when it receives a pressure equal to or higher than a predetermined threshold.
When a signal is output from the piezoelectric sensor 400, the wireless tag 500 transmits a wireless signal.

As shown in FIG. 1, three columns 300 and 301 support the top plate 200, and the piezoelectric sensor 400 is inserted between the column 300 and the top plate 200. The top board 200 has a shape and a size obtained by dividing the ceiling by a diagonal line and removing (cutting out) the entrance / exit portion of the manhole 100 from a triangle corresponding to the shape and size of the half of the ceiling, and near each vertex of the triangle And is supported by three columns 300 and 301.
The top plate 200 does not receive pressure from the ceiling when there is no sign that the manhole 100 will collapse, specifically, when the ceiling of the manhole 100 is not distorted. At this time, the top plate 200 applies pressure to the piezoelectric sensor 400 by its own weight. On the other hand, when there is a sign that the manhole 100 collapses, specifically, when the ceiling of the manhole 100 is distorted, pressure is applied from the ceiling. At this time, the top plate 200 applies pressure to the piezoelectric sensor 400 by pressure received from the ceiling in addition to its own weight. The top plate 200 is installed along the ceiling in the vicinity of the ceiling, such as being installed in contact with the ceiling, so as to receive pressure when the ceiling is distorted.
When pressure equal to or higher than a predetermined threshold is applied, the piezoelectric sensor 400 outputs a signal to the wireless tag 500. This threshold is set to a value larger than the pressure applied by the weight of the top board 200, and the piezoelectric sensor 400 does not output a signal when there is no sign that the manhole 100 will collapse. When a signal is output from the piezoelectric sensor 400, the wireless tag 500 transmits a wireless signal including information indicating that a sign that the manhole 100 has collapsed has been detected. Or simply, when there is no sign, the wireless tag 500 may not transmit a wireless signal, and may transmit a wireless signal when a sign is detected. In any case, by receiving the signal transmitted by the wireless tag 500, it is possible to detect a sign that the manhole 100 will collapse on the ground (for example, on the road on the manhole 100) without entering the manhole 100.

As described above, the top plate 200 has a triangular shape, and the three support columns 300 and 301 support the vicinity of each vertex of the triangle of the top plate 200, so that the ceiling of the manhole 100 is distorted and the top plate 200 When a part is pushed downward, the force is applied to all three columns 300 and 301, and the force is also applied to the piezoelectric sensor 400 inserted between the column 300 and the top plate 200. Therefore, regardless of which of the three vertices of the top plate 200 the piezoelectric sensor 400 is arranged and when pressure from the ceiling is applied to any part of the top plate 200, one piezoelectric sensor 400 is used for manholes. A sign that 100 ceilings will collapse can be detected.
In addition, when the length of each side of the top plate 200 is longer than the diameter of the entrance / exit, for example, the top plate 200 is folded or assembled, and is expanded or assembled inside the manhole 100.

In FIG. 1, the case of using one set of manhole abnormality detection system 1 has been described, but by using two sets of manhole abnormality detection system 1, the entire ceiling can be covered. Thereby, when any part of the ceiling is distorted, a sign that the manhole 100 is collapsed can be detected.
FIG. 2 is a diagram illustrating an arrangement example using two sets of manhole abnormality detection systems 1.
In the figure, two columns 300 and 301 each support two top plates 200. Here, each of the two columns 300 supports the two top plates 200, and a total of four columns 300 and 301 are located at the four corners of the manhole 100. Further, as described in FIG. 1, the piezoelectric sensor 400 is inserted between the support column 300 and the top plate 200.

Each of the two top plates 200 has a shape and a size obtained by cutting out the entrance / exit portion of the manhole 100 from a triangle corresponding to the shape and size of the half of the ceiling of the manhole 100. Can be used to cover the entire ceiling.
As in the case described with reference to FIG. 1, each of the two top plates 200 has a triangular shape, and the columns 300 or 301 support the vicinity of each apex of the top plate 200, so that the number of top plates is at most The same number of piezoelectric sensors 400 and wireless tags 500 can detect any portion of the ceiling that is distorted. Thereby, since the sign of a manhole collapse can be detected without a person entering a manhole, the burden at the time of a person entering a manhole and performing an inspection can be reduced. And since the existing manhole can be used for a long time by repairing the manhole at an appropriate time, the burden of repairing or newly installing the manhole can be reduced.
Further, since each of the two support columns 300 supports the two top plates 200, the two support columns 301 can be reduced. Since one column 300 supports the two top plates 200, the piezoelectric sensor inserted between one column 300 and the top plate 200 can be applied to any top plate 200 when pressure is applied. It is possible to detect a sign that the manhole 100 is collapsed due to pressure. Therefore, only one of the columns 300 may be used, and the other column 300 may be replaced with the column 301. Thereby, the number of piezoelectric sensors 400 and wireless tags 500 can be reduced.

  On the other hand, when two piezoelectric sensors 400 and two wireless tags 500 are used as shown in FIG. 2, the two wireless tags 500 are arranged at positions separated from each other such as diagonal positions of a ceiling rectangle. When both the piezoelectric sensors 400 detect the sign of the manhole 100 collapse and both the wireless tags 500 transmit wireless signals, the wireless signal can be transmitted over a wide range, and the sign of the manhole 100 collapse can be detected over a wide range on the ground. . Further, for example, when a receiving device is mounted on a vehicle and the vehicle is traveling at high speed, even if reception of a wireless signal transmitted from one wireless tag 500 fails due to noise mixed by chance, the other The possibility that a sign of the collapse of the manhole 100 can be detected even when the reception conditions are severe, such as being able to receive a wireless signal transmitted from the wireless tag 500, increases.

In addition, arrangement | positioning of the support | pillars 300 and 301 is not restricted to what was shown in FIG.
FIG. 3 is a diagram showing another arrangement example using two sets of manhole abnormality detection systems 1.
In the same figure, arrangement | positioning of the support | pillars 300 and 301 differs from the case of FIG. In FIG. 3, the column 300 and the piezoelectric sensor 400 are arranged near the top of the top plate 200 that is not adjacent to the other top plate 200.
3, the entire rectangular ceiling can be covered with two top plates, as in FIG. When a pressure that is a sign of the collapse of the manhole 100 is applied to one of the top plates 200, the pressure is transmitted to the three columns 300 and 301 that support the top plate 200. Therefore, by inserting the piezoelectric sensor 400 between one of the three columns and the top plate 200, the pressure from the top plate 200 as a sign of the collapse of the manhole 100 can be detected. Therefore, as in the case of FIG. 2, the pressure as a sign of the collapse of the manhole 100 can be detected regardless of the portion of the ceiling that is distorted.

Next, a method for preventing erroneous detection due to vibration such as passage of a large vehicle will be described.
Most of the manholes have entrances and exits on the surface of the road where vehicles come and go, and manholes are buried under the road. For this reason, for example, if a large vehicle such as a transportation truck travels on the road, it is considered that the vibration is transmitted to the manhole.
Also, when the ceiling or side wall of the manhole is distorted, due to deterioration of the concrete on the ceiling or side wall, after the pressure applied to the concrete exceeds the pressure that can be withstood by the concrete, a large strain may occur at a time with shaking. Conceivable.
The piezoelectric sensor 400 can detect the steady pressure due to the distortion of the ceiling as described above, and can also detect the temporary pressure due to the shaking. In particular, by detecting a vibration when a wall on which a top plate or a sensor is not installed is distorted, a sign that the manhole 100 is collapsed can be detected more accurately.

FIG. 4 is a diagram illustrating an example of a vibration transmitted to the manhole 100 when the vehicle passes and a vibration caused by a sign of collapse.
The graph (G1) in the figure is a graph showing the vibration transmitted to the manhole 100 when a large vehicle such as a truck travels on the road above the manhole 100. On the other hand, the graph (G2) is a graph showing shaking as a sign of the manhole collapse. As shown in these graphs, the magnitude of shaking differs between shaking when passing through the vehicle and shaking as a sign of manhole collapse. Between the road and the manhole 100, soil having a thickness of about 1 meter, for example, the depth of the entrance / exit is sandwiched. It is considered that a part of the vibration when passing through the vehicle is absorbed by the soil and the vibration reaching the manhole 100 is relatively small. On the other hand, the shaking when the ceiling or the side wall is distorted is exactly the shaking that occurs in the manhole 100, and is considered to be larger than the shaking when the vehicle is passing.

Therefore, a threshold value having a value larger than the pressure generated by the vibration when the vehicle passes is provided, and the wireless tag 500 indicates information indicating a sign of the collapse of the manhole 100 only when the piezoelectric sensor 400 detects a pressure larger than the threshold value. To send.
As a method for realizing such a threshold value, for example, as the piezoelectric sensor 400, a piezoelectric sensor that outputs a signal to the wireless tag 500 only when a pressure larger than the threshold value is detected is used.
In addition, you may make it detect the pressure more than a threshold value with another method. For example, the piezoelectric sensor 400 may output the pressure value to the wireless tag 500. In this case, the wireless tag 500 stores a threshold value in advance, and determines whether the pressure value output from the piezoelectric sensor 400 is greater than the threshold value. When it determines with it being larger than a threshold value, the wireless tag 500 transmits the information which shows having detected the pressure more than a threshold value as information which shows a collapse omen.

  Alternatively, as shown in FIG. 4, a spring 600 may be inserted at a position between the top plate 200 and the support column 300 where the piezoelectric sensor 400 is inserted. When the magnitude of the swing is smaller than the above-described threshold, the spring 600 receives all the pressure, and no pressure is applied to the piezoelectric sensor 400. On the other hand, when the magnitude of the vibration exceeds the above-described threshold value, the pressure is not received by the spring 600 alone, and pressure is also applied to the piezoelectric sensor 400. Thereby, when there is a shake larger than the threshold, the wireless tag 500 transmits information indicating that the pressure has been detected as information indicating the sign of collapse.

In this way, by detecting the shaking when the ceiling or the side wall (described later in the fourth embodiment) is distorted, it is possible to more accurately detect the sign that the manhole 100 will collapse. Furthermore, erroneous detection can be prevented by not detecting shaking during vehicle travel.
Note that, as described in FIG. 1, the threshold value is larger than the pressure applied to the piezoelectric sensor 400 by the weight of the top plate 200 (when the manhole 100 is not predicted to collapse, the piezoelectric sensor 400 does not output a signal). Threshold) may be realized by these configurations.

Further, the piezoelectric sensor 400 and the wireless tag 500 may detect both a constant pressure due to distortion of the ceiling or the like and a pressure due to shaking when the distortion occurs. For example, the wireless tag 500 has a threshold value larger than the pressure applied to the piezoelectric sensor 400 by the weight of the top board 200 (hereinafter referred to as “static pressure threshold value”) and a pressure generated by a vibration when the vehicle travels. Are stored in advance as a threshold having a larger value (hereinafter referred to as a “shake threshold”). Then, the piezoelectric sensor 400 outputs a pressure value to the wireless tag 500, and the wireless tag 500 compares the pressure value output from the piezoelectric sensor 400 with each threshold value. Then, a signal including different information is output when the pressure value output from the piezoelectric sensor 400 is determined to be larger than the static pressure threshold and when the pressure value is determined to be larger than the shaking threshold. .
By receiving the signal output from the wireless tag 500 on the ground, it is possible to detect both the constant pressure due to distortion of the ceiling and the like and the pressure due to shaking when the distortion occurs.

Note that the wireless tag 500 may detect the magnitude of shaking by calculating the amount of change in the pressure value output from the piezoelectric sensor 400. Thereby, it is possible to distinguish the constant pressure due to the distortion of the ceiling or the like and the shaking at the time of the occurrence of the distortion, and to detect the sign of the collapse of the manhole 100 more accurately.
Alternatively, the manhole abnormality detection system 1 may further include an acceleration sensor. When this acceleration sensor detects a shake, it is possible to detect a shake at the time of occurrence of distortion as a sign of the collapse of the manhole 100.

<Second Embodiment>
FIG. 5 is a configuration diagram showing a schematic configuration of a manhole abnormality detection system according to the second embodiment of the present invention.
In the figure, a manhole abnormality detection system 2 is constructed inside a manhole 100 and includes a top plate 201, a support 300, a piezoelectric sensor 400, and a wireless tag 500. Among these, the top plate 201, the support column 300, and the piezoelectric sensor 400 are combined to correspond to the strain detection unit. As described below, when the ceiling of the manhole is distorted, the top plate 201 is removed from the ceiling of the manhole. The pressure received by the piezoelectric sensor 400 increases, and the piezoelectric sensor 400 detects the distortion of the ceiling of the manhole based on the increase in pressure.
In the figure, the same reference numerals (100, 300, 400, 500) are assigned to portions having the same functions as those in FIG.
The manhole of the present embodiment is different from the manhole abnormality detection system 1 of the first embodiment in that the top plate 201 has a shape and a piezoelectric sensor is provided on all the columns.

  The top plate 201 has a rectangular shape according to the rectangular ceiling of the manhole 100. The size of the top plate 201 is also a size corresponding to the size of the ceiling. Further, the top plate 201 is provided with a hole corresponding to the shape and size of the entrance / exit so as not to block the entrance / exit of the manhole 100. The four columns 300 support the rectangular top plate 201 near the four apexes, and one piezoelectric sensor 400 is inserted between the top plate 201 and all the columns 300. Similarly to the top plate 200, the top plate 201 is also installed along the ceiling such that it is placed in contact with the ceiling so that it receives pressure when the ceiling is distorted.

When the ceiling is distorted as a sign of the collapse of the ceiling (a part of the ceiling is deformed so as to be lowered), a pressure to push the top plate 201 downward is applied. Further, the pressure to be pressed is applied to the piezoelectric sensor 400 via the top plate 201. Then, the piezoelectric sensor 400 outputs a signal indicating that pressure has been received to the wireless tag 500. When a signal is output from the piezoelectric sensor 400, the wireless tag 500 transmits a signal indicating a sign of a manhole collapse by radio waves. For example, by receiving this radio wave on the ground above the manhole 100, it is possible to detect a sign of manhole collapse without entering the manhole 100.
As shown in FIG. 5, when the top plate is supported by four or more columns, it is considered that when a pressure is applied from the ceiling to the top plate, no pressure is applied to some columns. Therefore, as described above, one piezoelectric sensor 400 is inserted between the top plate and all the support columns that support the top plate.

Since the manhole abnormality detection system 2 does not use the column 301 but uses the same column 300, the column 300 can be shared, and the burden of designing a plurality of types of columns and the generation of a plurality of types of columns can be reduced.
Further, since the manhole abnormality detection system 2 covers the ceiling of the manhole 100 with one top plate 201, the top plate 201 may be designed according to the shape of the ceiling. For example, the ceiling shape is divided into a plurality of triangles. There is no need for complicated design such as designing multiple top plates. In this respect, the design burden can be reduced. Moreover, it is not necessary to prepare a plurality of top plates. In addition, since only one top plate is used, it is not necessary to consider how the support columns are arranged in order to support a plurality of top plates with one support column.

In addition to the rectangular ceiling shown in FIG. 5, various ceiling shapes can be covered with a single top plate.
FIG. 6 is a diagram illustrating an example in which an irregularly shaped manhole (other than a rectangle) is covered with a single top plate. FIG. 4A shows the case of an “L” -shaped manhole 102. FIG. 4B shows the case of a “T” -shaped manhole 103. FIG. 6C shows the case of a “ten” -shaped manhole 104. Such “L” -shaped, “T” -shaped, and “ten” -shaped manholes exist, for example, at intersections of roads.
For example, in the case of an “L” -shaped ceiling as shown in FIG. 5A, an “L” -shaped top plate 202 is used in accordance with the shape of the ceiling. Since the “L” -shaped ceiling has six corners, a pillar 300 is arranged at each corner of the ceiling, and one piezoelectric sensor 400 is provided between each pillar 300 and the top plate 202. insert.

Similarly, in the case of the “T” -shaped and “ten” -shaped ceilings, respectively, as shown in FIGS. 5B and 5C, the “T” -shaped top plate 203 according to the shape of the ceiling. And a “ten” -shaped top plate 204 is used. Since the “T” -shaped and “ten” -shaped ceilings have 8 and 12 corners, respectively, the columns 300 are arranged at the corners of the ceiling, and the columns 300 and the top plate 202 are arranged. One piezoelectric sensor 400 is inserted between each.
In this way, even in a manhole having a shape other than a rectangle, the entire ceiling can be covered with a single top plate, and a sign that the manhole collapses can be detected in the same manner as in the case of the rectangle described in FIG.

Such manholes 102 to 104 having an irregular shape such as an “L” shape are present in a small number compared to the rectangular manhole 100. Therefore, even if the ceilings of the manholes 102 to 104 having these shapes are designed to be covered with the triangular top plate 200, the versatility is poor. Therefore, the piezoelectric sensor 400 is inserted between all the columns 300 that prepare the top plates 202 to 204 in accordance with the shapes of the manholes 102 to 104 and stand at the corners without taking time and manpower for designing the top plate. It is effective to do.
Similarly to the top plate 200, the top plate 202 is installed in contact with the ceiling so as to receive pressure when the ceiling is distorted, or the distance from the ceiling is a predetermined distance (for example, It is installed near the ceiling, such as 5 millimeters or less.

<Third Embodiment>
FIG. 7 is a configuration diagram showing a schematic configuration of a manhole abnormality detection system according to the third embodiment of the present invention.
In the figure, the manhole abnormality detection system 3 is constructed inside a manhole 105, and includes a top plate 205, a support 305, a piezoelectric sensor 400, and a wireless tag 500. Among these, the top plate 205, the support column 305, and the piezoelectric sensor 400 are combined to correspond to the strain detection unit. As described below, when the ceiling of the manhole is distorted, the top plate 205 is removed from the ceiling of the manhole. The pressure received by the piezoelectric sensor 400 increases, and the piezoelectric sensor 400 detects the distortion of the ceiling of the manhole based on the increase in pressure.
In the figure, parts having the same functions as those in FIG. 1 are denoted by the same reference numerals (400, 500), and description thereof is omitted.
The manhole abnormality detection system 3 according to the present embodiment corresponds to an uneven ceiling using the top plate 205 and the column 305.

  For example, many manholes generated based on an old standard more than 30 years ago have irregularities on the ceiling due to the passage of many years from construction. Since these manholes are generated based on the old standard and the passage of many years, the possibility of collapse is relatively high, and it is highly necessary to determine whether or not the manhole collapses. However, a flat top plate like the top plate 200 in FIG. 1 has few portions where the top plate is in contact with the ceiling due to the unevenness of the ceiling, and a gap is generated between the top plate and the ceiling. When the ceiling is distorted, there is a possibility that the pressure is not transmitted to the top plate due to this gap, and the sign of the manhole collapse cannot be accurately detected. In order to more accurately detect the signs of manhole collapse, a top plate with more contact with the uneven ceiling is required.

The top plate 205 includes a subdivided top plate panel 210, a trusted frame (Trussed Frame), and an unevenness adjusting bolt 220. The column 305 includes a column part 310, a height adjustment bolt 320, and a leg part 330.
The trust frame 230 is constructed by combining rod-like members such as pipes, and as shown in the figure, a plurality of minimum unit triangles are combined. The trust frame 230 as a whole also has a shape and size corresponding to the shape and size excluding the entrance / exit portion of the manhole 105 from the triangle obtained by dividing the ceiling rectangle by the diagonal line. The trust frame 230 can be disassembled into a triangular frame of a minimum unit and further to three rod-shaped frame parts that form the triangular frame of the minimum unit. Therefore, at the time of loading into the manhole 105, it can be loaded from the entrance / exit of the manhole 105 in a disassembled state, and assembled into the ceiling size inside the manhole 105.

The subdivided top panel 210 has a size and a shape corresponding to the minimum unit triangle of the trust frame 230. The manhole abnormality detection system 3 includes the same number of subdivided top panel 210 as the minimum unit triangle of the trust frame 230.
The unevenness adjustment bolt 220 is attached to the trust frame 230 and can adjust the length (extruding condition) from the trust frame 230. For example, the unevenness adjusting bolt 220 is threaded, and the trust frame 230 has a screw hole corresponding to the thread. The screw hole may be formed in a member constituting the trust frame 230, or a nut-like member may be joined to the trust frame 230. When the concave / convex adjusting bolt 220 is inserted into the screw hole of the trust frame 230 and turned to the right, the concave / convex adjusting bolt 220 protrudes from the plane of the trust frame 230 (a plane including the trust frame 230) and turns to the left. And the protrusion of the unevenness adjustment bolt 220 with respect to the plane of the trust frame 230 becomes small.
As shown in FIG. 7, the top plate 205 is attached to the assembled trust frame 230 with the unevenness adjustment bolt 220, and is supported by the unevenness adjustment bolt 220, one for each triangle of the minimum unit of the trust frame 230. The subdivided top panel 210 is arranged. Here, each of the subdivided top panel 210 is supported at three points from below by three uneven adjustment bolts.

The column part 310 has, for example, a pipe shape, and the other column part 310 or a part of the leg part 330 can be inserted. The leg part 330 includes a leg (a triangular plate shown in the figure) in addition to the same shape as the support part 310. This leg stabilizes the column part 310 in a standing state. The height adjustment bolt 320 is a bolt that connects the column parts 310 to each other or the column part 310 and the leg part 330. Details will be described later.
As shown in FIG. 7, a part of the leg part 330 is inserted into the column part 310 and fixed with the height adjustment bolt 320, and this column part 310 is further inserted into another column part 310 and fixed with the height adjustment bolt 320. To do. The column 305 is formed by repeating this insertion into the other column part 310 and fixing with the height adjustment bolt 320. And the height of the support | pillar 305 can be adjusted with the number of the support | pillar parts 310 and the grade of the insertion mentioned later.
Further, as shown in FIG. 7, the three columns 305 support the top plate 205 from below in the vicinity of each vertex of the triangular top plate 205. As in the case of FIG. 1, the piezoelectric sensor 400 is inserted between one of the columns 305 and the top plate 205, and the wireless tag 500 is connected to the piezoelectric sensor 400.

  FIG. 8 is a cross-sectional view of the top plate 205 installed so as to cover the ceiling as seen from the lateral direction (on the plane including the trust frame 230). As shown in the figure, the top plate 205 is installed along the ceiling of the manhole 105 so as to be in contact with the ceiling. In addition, the figure has shown about the case where the distortion of a ceiling is very large for description. The present invention can be applied to such a case where the distortion is very large as well as the case where the distortion is smaller. Further, as described above, each of the subdivided top panel 210 is supported by the three unevenness adjusting bolts 220. However, in FIG. The irregularity adjustment bottle is shown.

  As shown in the figure, the height and orientation of the subdivided top panel 210 can be adjusted by adjusting the degree of protrusion of the unevenness adjusting bolt 220. By adjusting the height and direction of the subdivided top panel 210 in accordance with the unevenness of the ceiling, each of the subdivided top panel 210 can come into contact with the ceiling at least at one or more places. As a result, any portion of the ceiling covered by the top plate 205 is distorted, and the top panel 210 that has subdivided the pressure caused by the distortion receives the concavo-convex adjustment bolt 220, the trust frame 230, and the like. The pressure can be applied to the piezoelectric sensor 400 via the, and a sign that the manhole 105 is collapsed can be detected.

Further, as described with reference to FIG. 2, by covering the entire ceiling using the plurality of manhole anomaly detection systems 3, the manhole 105 is collapsed when any part of the ceiling is distorted. Can detect signs. As described in FIG. 2, out of the rectangle formed by the two top plates 205, each of the two support columns 305 positioned at diagonally opposite sides of the two top plates 205 is composed of two pieces. By supporting the top plate 205, two top plates can be supported by the four support columns 305.
The shape of the trust frame 230 is not limited to a triangle, and the shape and size corresponding to the shape and size of the ceiling of the manhole (excluding the entrance / exit portion of the manhole are the same as described in the second embodiment). Shape and size).

FIG. 9 is a diagram illustrating an example in which two support parts 310 are coupled using the height adjustment bolt 320.
As shown in the lower side of the figure, the column part 310 has a plurality of holes through which the height adjustment bolts 320 are inserted. The plurality of holes have different height positions and lateral positions. Moreover, the support | pillar part 310 has a some hole which puts the height adjustment bolt 320 also in the lower part, and these holes also mutually differ in a height position and a horizontal position. The reason why the horizontal position is different for each hole is to maintain the strength of the prop parts.

  A method of adjusting the height of the column 305 using this hole will be described. Select one of the holes in the upper part of the pillar part 310 (hereinafter, this pillar part will be referred to as “lower pillar part (lower side)”), and from the holes in the lower part of the other pillar part 310 Then, a hole in a horizontal position corresponding to the horizontal position of the previous hole is selected (hereinafter, this column part is referred to as “column part (upper side)”). The upper part of the column part 310 (lower side) is inserted into the lower part of the column part 310 (lower side), and the two selected holes are aligned with each other. Then, the height adjusting bolt is inserted into the combined hole, and the two support parts 310 are joined.

For example, the lowest hole from the plurality of holes on the upper part of the pillar part 310 (lower side) and the highest hole from the plurality of holes on the lower part of the pillar part 310 (upper side) are selected and raised. Insert the adjustment bolt 320. When the height adjustment bolts 320 are inserted into the respective holes thus selected, the entire support column 305 including these support column parts 310 is shortened, and the top plate 205 can be lowered.
Conversely, the hole at the highest position from the plurality of holes at the top of the column part 310 (lower side) and the hole at the lowest position from the plurality of holes at the bottom of the column part 310 (upper side) are selected. When the height adjustment bolt 320 is inserted into each of the holes selected in this way, the column 305 as a whole becomes longer and the top plate 205 can be raised.
As described above, by selecting a plurality of holes in the column part 310 and inserting the height adjustment bolt 320, the height of the top plate 205 can be changed to match the height of the ceiling of the manhole 105.

FIG. 10 is a diagram illustrating an example of a manhole abnormality detection system 4 in which a piezoelectric sensor is inserted between the top panel and the unevenness adjusting bolt.
In FIG. 7, the piezoelectric sensor 400 is inserted between the support 305 and the top plate 205, but in FIG. 10, the piezoelectric sensor is applied to one of the three uneven adjustment bolts 220 that support one subdivided top plate 205. A sensor 400 is attached, and the piezoelectric sensor 400 is inserted between the top panel 210 and the unevenness adjusting bolt.
When the subdivided top panel 210 receives pressure from the ceiling of the manhole 105, the pressure is transmitted to the piezoelectric sensor 400. As described with reference to FIG. 1, the piezoelectric sensor 400 stores a threshold value having a value larger than the pressure due to the weight of the subdivided top panel 210. To output a signal. When a signal is output from any of the piezoelectric sensors 400, the wireless tag 500 transmits a wireless signal.

As in the case of FIG. 9, each of the subdivided top panel 210 can be brought into contact with the ceiling of the manhole 105 by adjusting the column 305 and the unevenness adjusting bolt 220, so that the ceiling part covered by the top panel 205 Of these, even if distortion occurs in any part, it is possible to detect a sign that the manhole 105 will collapse.
Also in the case of FIG. 10, as in the case of the first embodiment, the two manhole abnormality detection systems 4 are used to predict whether the manhole 105 will collapse regardless of the distortion of any part of the entire ceiling surface. It can be detected.

Furthermore, since the piezoelectric sensor 400 is installed for each subdivided top panel 210, it is possible to identify which subdivided top panel 210 is receiving pressure from the ceiling. For example, a signal that the piezoelectric sensor 400 transmits to the wireless tag 500 when pressure is detected is a signal that differs for each piezoelectric sensor 400, and the wireless tag 500 outputs a signal that is output from the piezoelectric sensor 400 for each piezoelectric sensor 400. Try to send different radio signals. By receiving this wireless signal on the ground, it is possible to specify which part of the ceiling is distorted without entering the manhole 105.
Many of the manholes made according to the old standards described above are constructed of concrete only, and there are no reinforcing bars inside the concrete. In concrete manhole ceilings without such reinforcing bars, there is a possibility that parts with weak structures will collapse. Therefore, by capturing a sign of collapse for each subdivided top panel 210 and transmitting a different radio signal for each top panel, for example, by receiving this radio signal, how many top panels 210 have collapsed. You can count the number of signs that you have caught and figure out the scale of signs of collapse (ceiling distortion). As a result, it is possible to obtain information on whether or not a part of the repair / renovation can be completed, or whether it should be completely replaced (transferred to another manhole).

If the ceiling of the manhole is substantially flat like the manhole 100 in FIG. 1, the top plate may be configured with only the trust frame.
FIG. 11 is a diagram illustrating an example of a manhole abnormality detection system 5 that uses a top plate configured only by a trust frame and a manhole 105 with an uneven ceiling.
As shown in the figure, a top plate 206 supported by a support column 305 is installed in the manhole 105, and a piezoelectric sensor 400 is inserted between the support column 305 and the top plate 206. The top plate 206 does not include the subdivided top plate panel 210 and the unevenness adjustment bolt 220 and is configured only by the trust frame 230.
If the ceiling is substantially flat like the manhole 100 in FIG. 1, there are many portions where the ceiling and the trust frame 230 are in contact with each other, and any portion of the ceiling portion covered by the top plate 206 is distorted. It can be expected that a sign that the manhole 105 will collapse can be detected.
Further, as in the case of the first embodiment, by using the two sets of manhole abnormality detection systems 5, it is possible to detect a sign that the manhole 105 is collapsed regardless of which portion of the entire ceiling surface is distorted.
In the configuration shown in FIG. 11, the number of necessary members can be reduced because the subdivided top panel 210 and the unevenness adjusting bolt 220 are unnecessary, and therefore, the assembly of the manhole abnormality detection system is easy.

On the other hand, when the ceiling is uneven as in the manhole 105, as shown in FIG. 11, there are few portions where the trust frame 230 and the ceiling are in contact, and there is a possibility that the sign that the manhole 105 will collapse cannot be accurately captured. is there. Therefore, when the ceiling has irregularities, the top plate 207 with the irregularity adjusting bolts 220 attached to the trust frame 230 is used.
FIG. 12 is a diagram illustrating an example of the manhole abnormality detection system 6 using the top plate of the trust frame to which the unevenness adjusting bolt 220 is attached and the top plate of the manhole 105 having unevenness on the ceiling.
As in the case of FIG. 7, the support column 305 and the top plate 207 are installed in the manhole 105, and the piezoelectric sensor 400 that detects the pressure change is inserted between the support column 305 and the top plate 207. A wireless tag 500 that wirelessly transmits information to the ground is connected to the piezoelectric sensor 400.

As described with reference to FIG. 7, the length (extent) of each unevenness adjusting bolt 220 from the trust frame 230 can be adjusted. By adjusting the length of each unevenness adjusting bolt 220 from the trust frame 230, as shown in FIG. 12, all the unevenness adjusting bolts can be set to contact the ceiling. Accordingly, the top plate 207 formed of the unevenness adjusting bolt 220 and the trust frame 230 shown in FIG. 12 comes into contact with the ceiling of the manhole 105 at a number of locations that match the number of the unevenness adjusting bolts 220. The stress generated by the deformation of the ceiling of the manhole 105 is transmitted to the detection sensor (piezoelectric sensor 400) via the trust frame 230 from the unevenness adjusting bolt 220 in contact with the ceiling, and the detected information is transmitted by the wireless tag 500. It is sent to the ground by radio waves.
As described above, since the top plate 207 and the ceiling are in contact with each other at many portions, it is possible to detect a sign that the manhole 105 will collapse regardless of which portion of the ceiling portion covered by the top plate 207 is distorted. I can expect.
Further, as in the case of the first embodiment, by using the two sets of manhole abnormality detection systems 6, it is possible to detect a sign that the manhole 105 is collapsed regardless of which part of the entire ceiling surface is distorted.

<Fourth Embodiment>
FIG. 13: is a block diagram which shows schematic structure of the manhole abnormality detection system in the 4th Embodiment of this invention.
The manhole abnormality detection system 7 of this embodiment includes a piezoelectric sensor 400 that detects the pressure on the side wall in addition to the piezoelectric sensor 400 that detects the pressure on the ceiling of the manhole.
In the figure, the manhole abnormality detection system 7 is constructed inside a manhole 100 and includes a top plate 201, a column 300, a piezoelectric sensor 400, a wireless tag 500, a side plate 700, and a beam 800. Among these, the side plate 700, the support column 300, and the piezoelectric sensor 400 are combined to correspond to the strain detection unit. As will be described below, when the ceiling of the manhole is distorted, the top plate 201 is separated from the ceiling of the manhole. When pressure is received, the pressure received by the piezoelectric sensor 400 increases, and based on the increase in pressure, the piezoelectric sensor 400 detects distortion of the ceiling of the manhole.
In the figure, the same reference numerals (100, 201, 300, 400, 500) are given to portions having the same functions as those in FIG.
The side plate 700 is generated using a material that is difficult to deform, such as steel. The side plate 700 has a shape and a size corresponding to the shape and size of the side wall of the manhole 100, and is disposed along the side wall of the manhole 100.
The beam 800 is provided between the two struts 300 and keeps the distance between the two struts 300 constant.

The side plate 700 is disposed on all four side walls of the manhole 100.
As described with reference to FIG. 2, the piezoelectric sensor 400 is installed so as to be inserted between the support column 300 and the top plate 200. In addition, a beam 800 is provided between the support columns 300, and between the side wall of the manhole 100 and the support column 300. Also, the piezoelectric sensor 400 is inserted. As shown in the figure, the side plate is installed not only on the ceiling but also on the side wall, and the piezoelectric sensor 400 and the wireless tag 500 are also attached, so that distortion of the side wall in the manhole 100 can also be detected.
When the side wall 700 is distorted and pressure is applied to the side plate 700, the side plate 700 presses the piezoelectric sensor 400. Since the piezoelectric sensor 400 is pushed from the side plate 700, the pillar 300 is pushed. However, since the beam 800 is provided between the two pillars 300, the pillar 300 is not displaced even when pushed by the piezoelectric sensor 400. . Accordingly, the piezoelectric sensor 400 detects a pressure caused by being pressed from the side plate 700 and outputs a signal to the wireless tag 500. The wireless tag 500 to which a signal is output from the piezoelectric sensor 400 transmits a wireless signal. By receiving this radio signal on the ground, it is possible to detect a sign that the manhole 100 will collapse without entering the manhole 100.
In addition, although shown about the case where the top plate 201 demonstrated in FIG. 2 was used above, it is not restricted to this. This embodiment can be implemented in combination with any of the above-described embodiments, and thus any top plate described above can be applied.

<Fifth Embodiment>
FIG. 14: is a block diagram which shows schematic structure of the manhole abnormality detection system 8 in the 5th Embodiment of this invention.
In the figure, the manhole abnormality detection system 8 is built inside the manhole 100, and includes a top plate 201, a support 300, a piezoelectric sensor 400, a wireless tag 500, a beam 800, a pressure bolt 900, a fixture 910, a bolt base 920, and the like. It comprises.
In the figure, the same reference numerals (100, 201, 300, 400, 500, 800) are given to portions having the same functions as those in FIG.

When an external force acts near the center of the ceiling or side wall of the manhole and distortion occurs near the center of the ceiling or side wall, the ceiling or side wall is pushed into the manhole 100 by pushing the ceiling or the side wall against this external force. Distortion occurs.
On the other hand, as shown in FIG. 15, a stress v <b> 4 that presses against each other is generated at the position where the side wall and the side wall of the manhole 100 or the side wall and the ceiling intersect, that is, the corner of the manhole 100, and the space expands to the outside of the manhole 100. Is distorted.
Therefore, in addition to installing the piezoelectric sensor 400 to be inserted between the support column 300 and the top plate 200 as described with reference to FIG. 2, the piezoelectric sensor 400 is further provided at the corner of the manhole 100. The piezoelectric sensor 400 is fixed between the column 300 and the corner of the manhole 100 with a fixture 910, a pressure bolt 900, and a bolt base 920.
The fixture 910 fills the gap between the piezoelectric sensor 400 and the corner of the manhole and the gap between the piezoelectric sensor 400 and the pressurizing bolt 900, and the pressure from the corner of the manhole and the pressure from the pressurizing bolt 900 is applied to the piezoelectric sensor. Tell 400. The bolt base 920 is a pedestal into which the pressurizing bolt 900 is inserted, and is installed on the support column 300. The pressurizing bolt 900 is inserted into the bolt base 920 and the length from the bolt base 920 (adjustment degree) can be adjusted.

As shown in FIG. 14, the piezoelectric sensor 400 is sandwiched between fixtures 910 and fixed to the corners of the manhole with pressure bolts 900. Then, by adjusting the length of the pressurizing bolt 900, a predetermined constant pressure is applied to the piezoelectric sensor 400 in a steady state.
When the corner of the manhole 100 is distorted and the corner expands outward, the pressure applied to the piezoelectric sensor 400 decreases. The example is shown in the graph (upper side) of FIG. As shown in this graph, the piezoelectric sensor 400 installed at the corner of the manhole is pressed between the corner of the manhole 100 and the pressure bolt 900 in a steady state. At the time of the sign of collapse, the pressure applied to the piezoelectric sensor 400 is reduced by deforming so that the space at the corner of the manhole swells.
On the other hand, the piezoelectric sensor 400 inserted between the support column 300 and the top plate 201 receives only pressure due to the weight of the top plate 201 in a steady state as shown in the graph (lower side) of FIG. At the time of the collapse sign, the pressure applied to the piezoelectric sensor 400 increases due to the ceiling protruding.

Thus, in the piezoelectric sensor 400 installed at the corner of the manhole, in contrast to the piezoelectric sensor 400 inserted between the support column 300 and the top plate 201, the pressure applied to the piezoelectric sensor 400 due to the sign of the collapse of the manhole is increased. Decrease. Therefore, in the piezoelectric sensor 400 installed at the corner of the manhole, contrary to the case of the piezoelectric sensor 400 inserted between the support column 300 and the top plate 201, the pressure to be detected is smaller than a predetermined threshold value. Occasionally outputs a signal indicating that a sign of manhole collapse has been detected. When a signal is output from the piezoelectric sensor 400, the wireless tag 500 transmits a wireless signal indicating that a sign of manhole collapse has been detected. By receiving this radio signal on the ground, it is possible to detect a sign that the manhole 100 will collapse without entering the manhole 100.
As in the fourth embodiment, this embodiment can be implemented in combination with any of the above-described embodiments, and thus, any top plate described above can be applied in addition to the top plate 201.

  The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and includes design changes and the like within a scope not departing from the gist of the present invention.

  The present invention is suitable for use in a manhole abnormality detection system and a manhole abnormality detection method.

1, 2, 3, 4, 5, 6, 7, 8 Manhole abnormality detection system 100, 102, 103, 104, 105 Manhole 200, 201, 202, 203, 204, 205, 206, 207 Top panel 210 Top panel 220 Concavity and convexity adjustment bolt 230 Trust frame 300, 301, 305 Prop 310 Prop part 320 Height adjustment bolt 330 Leg part 400 Piezoelectric sensor 500 Wireless tag 600 Spring 700 Side plate 800 Beam 900 Pressure bolt 910 Fixing tool 920 Bolt stand

Claims (12)

A strain detector installed along a manhole wall and detecting a strain of the manhole wall based on a change in pressure from the manhole wall;
When the distortion detection unit detects distortion of the wall of the manhole, a transmission unit that transmits a signal indicating that the distortion is detected;
A manhole anomaly detection system comprising: The wall of the manhole is a ceiling of the manhole having a rectangular shape;
The strain detector
A shape and size corresponding to the shape and size excluding the entrance / exit part of the manhole from two triangles obtained by dividing the manhole ceiling rectangle into two diagonal lines, and along the ceiling of the manhole A plurality of top plates to be installed;
A plurality of columns supporting each of the plurality of top plates from below;
A piezoelectric sensor that is installed between the top plate and the support column and detects pressure from the ceiling of the manhole received by the top plate;
Comprising
Each of the top plates is supported from below at three points by the three support columns,
The piezoelectric sensor is located between the top plate and the support column at any one of three points where the top plate is supported for each top plate,
The manhole abnormality detection system according to claim 1, wherein the transmission unit is a wireless tag that transmits a wireless signal. The wall of the manhole is the ceiling of the manhole;
The strain detector
From the shape and size of the ceiling of the manhole, the shape and size according to the shape and size excluding the entrance and exit portion of the manhole, a top plate installed along the ceiling of the manhole,
A plurality of supports for supporting the top plate from below;
A piezoelectric sensor that is installed between each of the columns and the top plate and detects pressure from the ceiling of the manhole received by the top plate;
Comprising
The manhole abnormality detection system according to claim 1, wherein the transmission unit is a wireless tag that transmits a wireless signal. The top plate is
A frame supported by the support;
A plurality of uneven adjustment bolts attached to the frame and adjusted in length from the frame so as to contact the ceiling of the manhole;
The manhole abnormality detection system according to claim 2 or 3, further comprising: The top plate is
A frame supported by the column having a variable length;
A plurality of uneven adjustment bolts attached to the frame and adjusted in length from the frame;
A plurality of top panel panels that are supported from below by the unevenness adjusting bolts and are installed at heights and orientations that contact the ceiling of the manhole according to the length of the unevenness adjusting bolts from the frame,
The manhole abnormality detection system according to claim 2 or 3, further comprising: The wall of the manhole is a side wall of the manhole;
The strain detector
A side plate having a shape and size according to the shape and size of the side wall of the manhole, and installed along the side wall of the manhole,
A plurality of support columns that support the side plate from the lateral direction;
A beam for fixing the position of the column;
A piezoelectric sensor that is installed between the support column and the side plate and detects pressure from the side wall of the manhole received by the side plate;
Comprising
The manhole abnormality detection system according to claim 1, wherein the transmission unit is a wireless tag that transmits a wireless signal. A strain detecting step installed along the manhole wall detects a strain of the manhole wall based on a change in pressure from the manhole wall;
When detecting distortion of the manhole wall in the distortion detection step, the transmission unit transmits a signal indicating that the distortion has been detected, and
The manhole abnormality detection method characterized by comprising. The wall of the manhole is a ceiling of the manhole having a rectangular shape;
The strain detector
A shape and size corresponding to the shape and size excluding the entrance / exit part of the manhole from two triangles obtained by dividing the manhole ceiling rectangle into two diagonal lines, and along the ceiling of the manhole A plurality of top plates to be installed;
A plurality of columns supporting each of the plurality of top plates from below;
A piezoelectric sensor that is installed between the top plate and the support column and detects pressure from the ceiling of the manhole received by the top plate;
Comprising
Each of the top plates is supported from below at three points by the three support columns,
The piezoelectric sensor is located between the top plate and the support column at any one of three points where the top plate is supported for each top plate,
The manhole abnormality detection method according to claim 7, wherein the transmission unit is a wireless tag that transmits a wireless signal. The wall of the manhole is the ceiling of the manhole;
The strain detector
From the shape and size of the ceiling of the manhole, the shape and size according to the shape and size excluding the entrance and exit portion of the manhole, a top plate installed along the ceiling of the manhole,
A plurality of supports for supporting the top plate from below;
A piezoelectric sensor that is installed between each of the columns and the top plate and detects pressure from the ceiling of the manhole received by the top plate;
Comprising
The manhole abnormality detection method according to claim 7, wherein the transmission unit is a wireless tag that transmits a wireless signal. The top plate is
A frame supported by the support;
A plurality of uneven adjustment bolts attached to the frame and adjusted in length from the frame so as to contact the ceiling of the manhole;
The manhole abnormality detection method according to claim 8 or 9, characterized by comprising: The top plate is
A frame supported by the column having a variable length;
A plurality of uneven adjustment bolts attached to the frame and adjusted in length from the frame;
A plurality of top panel panels that are supported from below by the unevenness adjusting bolts and are installed at heights and orientations that contact the ceiling of the manhole according to the length of the unevenness adjusting bolts from the frame,
The manhole abnormality detection method according to claim 8 or 9, characterized by comprising: The wall of the manhole is a side wall of the manhole;
The strain detector
A side plate having a shape and size according to the shape and size of the side wall of the manhole, and installed along the side wall of the manhole,
A plurality of support columns that support the side plate from the lateral direction;
A beam for fixing the position of the column;
A piezoelectric sensor that is installed between the support column and the side plate and detects pressure from the side wall of the manhole received by the side plate;
Comprising
The manhole abnormality detection method according to claim 7, wherein the transmission unit is a wireless tag that transmits a wireless signal.

Images