Detector

Abstract

To provide a detector that makes it possible to detect progress of displacement early with a discontinuous portion as a monitoring object with a simple configuration even if it is a dark place or a high place.SOLUTION: A detector 1 for detecting progress of displacement of a discontinuous portion M3, comprises: electric conductive arm parts 2 arranged across the discontinuous portion; a light 3 for notifying an energization state of the arm parts; a circuit body part 4 for forming an electric circuit including the arm parts; and a power supply part 5. In the detector, the electric circuit is disconnected by separating the arm parts and the circuit body part when generating displacement more than or equal to a predefined value in the discontinuous portion.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a detection device for detecting the progress of displacement at discontinuous locations such as joints and cracks.

Background Art

[0002] As disclosed in Patent Documents 1 to 3, the displacement of the tunnel lining concrete over time is monitored by measuring the internal space of the tunnel using a laser distance meter or a 3D scanner.

[0003] Further, Patent Document 4 discloses a tunnel crack position detection system for detecting the crack position of a tunnel by the change in resistance of a circuit of a conductive paint arranged in a ladder shape with respect to the tunnel lining. On the other hand, Patent Document 5 discloses a method for detecting relative movement of a concrete structure for detecting relative displacement by discoloration of a fiber-reinforced plastic.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Patent Document 5

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in the methods of measuring displacement using a laser distance meter or a 3D scanner as disclosed in Patent Documents 1 to 3, the measuring instrument may become large and interfere with building limits, or the occurrence of displacement can only be grasped during measurements performed at time intervals.

[0006] Further, in the system for detecting the change from a continuous surface to a discontinuous surface as disclosed in Patent Document 4, since it is unknown where the displacement occurs, the monitoring target becomes wide, and the installation, maintenance, and management of devices and the like require time and cost.

[0007] Furthermore, in the method of detecting relative displacement by the discoloration of fiber-reinforced plastic as disclosed in Patent Document 5, it becomes difficult to visually recognize when the monitoring target exists in a dark place or a high place such as a tunnel, and there is a risk of overlooking the occurrence of displacement.

[0008] Therefore, an object of the present invention is to provide a detection device that can detect the progress of displacement at an early stage even in a dark place or a high place with a simple configuration, with a discontinuous portion as the monitoring target.

Means for Solving the Problems

[0009] In order to achieve the above object, the detection device of the present invention is a detection device for detecting the progress of displacement at a discontinuous portion, and includes a conductive bridging portion disposed across the discontinuous portion, a notification portion for notifying the energization state of the bridging portion, a circuit body portion for forming an electric circuit including the bridging portion, and a power supply portion. The electric circuit is characterized in that when a displacement of a predetermined value or more occurs at the discontinuous portion, the bridging portion and the circuit body portion are separated and disconnected.

[0010] Here, the bridging portion can be configured to be attachable so as to be contactable with an arbitrary position in the end region of the circuit body portion. Further, the bridging portion can be configured to be fixed by a fixing jig attached to a position adjacent to the discontinuous portion.

[0011] Furthermore, the discontinuous portion is the boundary of the arc-shaped segment of the tunnel, and the bridging portion is fixed to the segment to be the displacement detection target and has an arm portion that projects with respect to the end region of the circuit body portion attached to the segments adjacent in the tunnel circumferential direction. And it is preferable that the notification unit is a light that lights up when the bridging portion is energized.

Advantages of the Invention

[0012] The detection device of the present invention configured as described above includes a conductive bridging portion arranged across the discontinuous portion, a notification portion that notifies the energized state of the bridging portion, and a circuit body portion that forms an electric circuit including the bridging portion, and the electric circuit is disconnected when a displacement of a predetermined value or more occurs at the discontinuous portion.

[0013] Therefore, the discontinuous portion can be limited as the monitoring target, and with a simple configuration, even in a dark place or a high place, the progress of the displacement can be detected early by the change of the notification portion. In particular, if the bridging portion is configured to be able to contact any position in the end region of the circuit body portion, the bridging portion can be installed at the position to be detected according to the state of the discontinuous portion.

[0014] Also, if the detection target is the arc-shaped segment of the tunnel and the bridging portion is configured as an arm portion that projects with respect to the end region of the circuit body portion, the amount of protrusion into the inner space of the tunnel can be reduced, and the device can be made less likely to break.

[0015] Furthermore, if the notification portion is a light that lights up when the bridging portion is energized, even when the discontinuous portion to be detected exists in a dark place or a high place, the inspector can easily confirm the lighting or extinguishing of the light visually.

Brief Description of the Drawings

[0016]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

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Figure 11

Embodiments for Carrying Out the Invention

[0017] Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is an explanatory diagram schematically showing the configuration of the detection device 1 of the present embodiment. Further, FIG. 2 is an explanatory diagram showing an installation example of the detection device 1 as seen in the cross section of a tunnel. Furthermore, FIG. 3 is a diagram for explaining in an enlarged manner the configuration around the arm portion 2 that becomes the bridging portion.

[0018] Tunnels such as general mountain tunnels are formed with an inner wall by a cylindrical lining M2 constructed of concrete, as shown in FIG. 2. Hereinafter, the arc direction of the cylindrical tunnel is referred to as the tunnel circumferential direction T1, and the direction in which the tunnel extends is referred to as the tunnel axial direction T2 (see FIG. 1).

[0019] In the concrete lining M2, due to aging deterioration, loosening of the back ground, water gushing, etc., discontinuous portions M3 such as cracks may occur as shown in FIG. 1. If such discontinuous portions M3 grow and punching failure occurs, it will lead to the collapse of concrete pieces, etc., so it is desirable to constantly monitor them as the detection target M1.

[0020] Therefore, in the present embodiment, a region adjacent to the discontinuous portion M3 of the lining concrete is set as the detection target M1, and the detection device 1 is installed so that it can be detected when the displacement of the discontinuous portion M3 progresses.

[0021] The detection device 1 of the present embodiment includes an arm portion 2 that serves as a conductive bridging portion disposed across the discontinuous portion M3, a notification portion (3) that notifies the energization state of the arm portion 2, a circuit main body portion 4 that forms an electric circuit including the arm portion 2, and a power supply portion 5.

[0022] FIG. 1 shows a configuration in which arm portions 2, 2 are respectively connected to two connection cables 41 of the circuit main body portion 4, and these arm portions 2, 2 are connected to both ends of a connection portion 22 disposed in the detection target M1 to form an electric circuit. That is, the arm portion 2 is disposed across the discontinuous portion M3 between the detection target M1 and the surrounding lining M2.

[0023] Connected to the circuit main body portion 4 in addition to the arm portion 2 connected via the connection cable 41 is a light 3 that serves as a notification portion. The light 3 lights up when the electric circuit is connected (closed), and goes out when the arm portion 2 and the circuit main body portion 4 are separated and the electric circuit is disconnected. The light 3 may be a visible light emitting portion or an invisible light emitting portion such as a black light.

[0024] In addition, a power supply unit 5 is connected to the circuit main body 4. The power supply unit 5 can use a battery, a storage battery, or the like. When using a battery or the like for the power supply unit 5, the detection device 1 can be easily installed anywhere. Also, in a place where power can be relatively easily supplied from wiring or the like, the power supply unit 5 can be connected to the wiring in the tunnel.

[0025] FIG. 3 is a diagram for explaining the configuration around the arm portion 2 in an enlarged manner, where FIG. 3(a) is a cross-sectional view and FIG. 3(b) is a plan view. Here, at the surface (inner peripheral surface) of the detection target M1 adjacent to the discontinuous portion M3, the end of the connection portion 22 is wired. On the other hand, at the surface (inner peripheral surface) of the lining M2 adjacent to the discontinuous portion M3, the end portion 411 which is the end region of the connection cable 41 is wired.

[0026] And the arm portion 2 is attached so as to straddle the end of the connection portion 22 and the end portion 411 of the connection cable 41. Specifically, the arm portion 2 with the end on the detection target M1 side fixed to the detection target M1 by the fixing jig 21 protrudes toward the end portion 411 side of the connection cable 41. For example, the arm portion 2 is fixed by attaching both sides of a plate 211 that presses the end of the arm portion 2 to the detection target M1 with a fixing jig 21 such as a bolt or a nut.

[0027] This arm portion 2 is made of a conductive material such as a metal plate of stainless steel or the like. On the other hand, regarding the end of the connection portion 22 and the end portion 411 of the connection cable 41, a conductive material such as a metal plate is also in an exposed state. Therefore, when the arm portion 2, the connection portion 22, and the end portion 411 are in contact with each other, the electric circuit is connected and the arm portion 2 is in an energized state.

[0028] On the contrary, when the arm portion 2 and the end portion 411 are separated and no longer in contact, the electric circuit is disconnected and no electricity passes through the arm portion 2. In short, when a displacement of a predetermined value or more occurs at the discontinuous portion M3, the end portion 411 of the connection cable 41 of the circuit main body 4 and the arm portion 2 are separated, so that the electric circuit is in a disconnected state.

[0029] FIG. 4 is an explanatory diagram schematically showing a detection state for detecting the progress of displacement of the discontinuous portion M3. When the arm portion 2 of the detection device 1 is arranged straddling the discontinuous portion M3, since the arm portion 2 is in contact with both the end portion 411 of the connection cable 41 and the communication portion 22, an electric circuit is formed and the light 3 is in a lit state.

[0030] On the other hand, when punching destruction occurs in the lining M2 and the detection target M1 moves to the inside space side T3 of the tunnel, in other words, when the displacement of the discontinuous portion M3 progresses, the arm portion 2 and the end portion 411 of the circuit main body portion 4 are separated and the electric circuit is disconnected, so the light 3 is in an extinguished state. If the light 3 that should be lit during normal times is extinguished, it can be recognized that the displacement of the discontinuous portion M3 is progressing.

[0031] Next, a method of using the detection device 1 of the present embodiment will be described. FIG. 5 is a flowchart exemplifying the flow of tunnel maintenance inspection using the detection device 1 of the present embodiment.

[0032] First, in step S1, the detection target M1 is specified by the detection device 1. For example, as shown in FIGS. 1 and 2, in the entire length of the tunnel, an area where a discontinuous portion M3 such as a crack has occurred in the lining M2 is specified.

[0033] Subsequently, in step S2, the detection device 1 is installed for the specified detection target M1. For example, as shown in FIG. 1, the arm portions 2 are respectively arranged so as to straddle at least two discontinuous portions M3 where the discontinuous portion M3 appears on the inner peripheral surface.

[0034] Then, the arm portions 2, 2 are connected by the communication portion 22, and the tip of the arm portion 2 protruding outside the detection target M1 is brought into contact with the end portion 411 of the connection cable 41 of the circuit main body portion 4. Further, a light 3 serving as a notification portion is incorporated or connected to the circuit main body portion 4. Furthermore, a power supply portion 5 is incorporated or connected to the circuit main body portion 4.

[0035] After installing the detection device 1 with respect to the detection target M1 and turning on the light 3 in this way, maintenance and inspection of the tunnel will be carried out as usual (step S3). Inside the tunnel, it is usually dark with little light, but if the light 3 is on, even near the apex of the tunnel, the inspector can confirm the lighting of the light 3 during the travel of the maintenance vehicle or during the walking patrol (step S4).

[0036] And when a displacement of a predetermined value (for example, about 3 mm - 5 mm) or more occurs at the discontinuous portion M3 and the arm portion 2 separates from the end portion 411 of the circuit main body portion 4, the electric circuit is disconnected and the light 3 goes out. During the travel of the maintenance vehicle or during the walking patrol, if the normally lit light 3 is off, the inspector can grasp that the displacement at the discontinuous portion M3 has progressed and the electric circuit has been disconnected.

[0037] After the extinction of the light 3 is confirmed, go to the on-site investigation as soon as possible and conduct a detailed investigation such as whether there is actually a movement in the detection target M1 and whether it can be said to be a sign of punching and destruction. Then, based on the results of those investigations, formulate an appropriate countermeasure plan.

[0038] Next, the operation of the detection device 1 of the present embodiment will be described. The detection device 1 of the present embodiment configured as described above includes a conductive arm portion 2 disposed across the discontinuous portion M3, a light 3 for notifying the energization state of the arm portion 2, and a circuit main body portion 4 that forms an electric circuit including the arm portion 2. When a displacement of a predetermined value or more occurs at the discontinuous portion M3, the electric circuit is disconnected.

[0039] Therefore, it is possible to limit the monitoring target to only the discontinuous portion M3 instead of the entire length of the tunnel, which is a wide range. With a simple configuration, even in a dark place or a high place, the progress of the displacement can be detected early by the extinction of the light 3. Also, until the light 3 goes out, regular measurement etc. are not required, and the maintenance burden can be reduced.

[0040] Moreover, if the arm portion 2 is extended and the end portion 411 of the circuit main body portion 4 is brought into contact with the arm portion 2, the amount of protrusion into the tunnel inner space side T3 is also small, and it does not interfere with the construction limit of the tunnel, which is a structure having a curved surface.

[0041] Furthermore, if the arm portion 2 is configured to be able to contact any position of the end portion 411 of the circuit main body portion 4, it can be installed at a position where it is desired to be detected early or a position where it is easy to attach according to the state around the discontinuous portion M3.

[0042] Also, if the device is such that the state of the notification unit changes depending on the presence or absence of contact, it can function stably even in a humid environment such as a tunnel. That is, it can be a simple and durable device.

[0043] Furthermore, if the arm portion 2 is arranged at a plurality of discontinuous portions M3, it can be detected even if there is any movement, so it can lead to early detection and early inspection. And if the notification unit is a light 3 that lights up or goes out depending on the presence or absence of contact, even when the detection target M1 is arranged at a high place in a dark place, the inspector can easily visually confirm the change in state during a walking patrol or the like.

Embodiment

[0044] Hereinafter, a detection device 1A in a form different from the detection device 1 of the above-described embodiment will be described with reference to FIGS. 6 and 7. Note that, for the description of the same or equivalent parts as those described in the above embodiment, the same terms or the same reference numerals will be used for the description.

[0045] In the above embodiment, the detection device 1 installed when a discontinuous portion M3 such as a crack occurs in the lining M2 of a mountain tunnel has been described. However, in the first embodiment, the case where the detection device 1A is installed in a shield tunnel in which a cylindrical tunnel lining is assembled by a plurality of arc-shaped segments will be described.

[0046] The tunnel excavated by the shield machine forms a cylindrical lining (outer shell) by combining members shaped like arc plates called segments, as shown in Fig. 6.

[0047] Segments include steel segments formed of steel, RC segments made of reinforced concrete, and composite segments formed by integrating steel and concrete. The RC segment is formed into an arc plate shape using only reinforced concrete. On the other hand, the composite segment is formed by filling concrete into a box-shaped inner space surrounded by making the peripheral edge of the skin plate into a wall shape with the outer peripheral surface side of the tunnel as a steel skin plate.

[0048] A plurality of segments are joined in the tunnel circumferential direction T1 to assemble into a ring, and the rings are joined in the tunnel axial direction T2 to become the lining of the cylindrical tunnel. Among the plurality of segments assembled in the tunnel circumferential direction T1, the last connected segment is called the K segment P1.

[0049] In Example 1, the installation method of the K segment P1 of the cross-sectional internal closing method will be described. That is, in the cross-sectional internal closing method, the K segment P1 is moved radially from the tunnel inner space side T3 and fitted between the adjacent segments P2, P2 on both sides. Then, by fitting this K segment P1, the segments P2, P2 are connected and the ring is completed.

[0050] In Example 1, the last connected K segment P1 is described as the detection target. A joint serving as a boundary P3 occurs between the K segment P1 and the segment P2 adjacent in the tunnel circumferential direction T1.

[0051] This joint is arranged in a staggered pattern so as not to be continuous in the tunnel axial direction T2 between the rings. For this reason, the position of the K segment P1 in the tunnel circumferential direction T1 is not constant in the tunnel axial direction T2, but in Example 1, the explanation will be given based on the position of the K segment P1 illustrated in Fig. 6.

[0052] In the detection device 1A of the first embodiment, movement of the K segment P1 by a predetermined value (for example, about 3 mm to 5 mm) or more toward the inner space side T3 of the tunnel is detected. Here, in the detection device 1 described in the above embodiment, the configuration in which the pair of arm portions 2, 2 serving as the bridging portion are connected by the connecting portion 22 has been described. However, in the detection device 1A of the first embodiment, the two connection cables 41, 41 of the circuit main body portion 4 are directly connected by a single bridging portion 2A.

[0053] That is, in the segments P2 on both sides of the K segment P1, end portions 411 that are end regions of the connection cable 41 are respectively wired to the surfaces (inner peripheral surfaces) of the segments P2 adjacent to the boundary P3, and the bridging portion 2A is installed so as to connect between the end portions 411, 411.

[0054] The bridging portion 2A is made of a conductive material such as a metal plate of stainless steel or the like. When the bridging portion 2A is in contact with both side end portions 411, the electric circuit is connected and the bridging portion 2A is in an energized state. On the other hand, when the bridging portion 2A and the end portion 411 are separated and no longer in contact, the electric circuit is disconnected, no electricity passes through the bridging portion 2A, and the electric circuit is in a disconnected state.

[0055] FIG. 7 is an explanatory diagram schematically showing a detection situation for detecting the displacement of the K segment P1. When the both ends (arm portions) of the bridging portion 2A of the detection device 1A are arranged straddling the boundary P3, since the bridging portion 2A is in contact with the end portion 411 of the connection cable 41, an electric circuit is formed and the light 3 is in a lit state.

[0056] On the other hand, when the K segment P1 comes out and moves to the inner space side T3 of the tunnel, in other words, when the displacement of the boundary P3 progresses, the end portion (arm portion) of the bridging portion 2A and the end portion 411 of the circuit main body portion 4 are separated and the electric circuit is disconnected, so the light 3 is in an extinguished state. If the light 3 that should be lit during normal times is extinguished, it can be recognized that the displacement of the boundary P3 is progressing.

[0057] In the case of the detection device 1A of the first embodiment configured as described above, it becomes possible to detect an abnormality such as the disengagement of the K segment P1 at an early stage with a small number of members. Further, the disengagement of the K segment P1 does not necessarily occur uniformly in all sections of the tunnel, but is more likely to occur in sections with severe ground conditions, for example, when the ground around the tunnel is soft. Therefore, the detection device 1A can also be installed only for the K segment P1 in sections with severe ground conditions.

[0058] Regarding other configurations and operational effects, since they are substantially the same as those in the above-described embodiment or other embodiments, the description thereof is omitted.

Embodiment

[0059] Hereinafter, a detection device 1B having a form different from the detection devices 1 and 1A of the above-described embodiment and the first embodiment will be described with reference to FIG. 8. Regarding the description of the parts that are the same as or equivalent to those described in the above-described embodiment or the first embodiment, the same terms or the same reference numerals will be used for the description.

[0060] Also in this second embodiment, the application to the shield tunnel described in the first embodiment will be used as an example for the description. The connection part 22B of the detection device 1B of this second embodiment is formed in a rectangle in plan view, unlike the U-shaped connection part 22 described in the above-described embodiment in plan view.

[0061] The connection part 22B is made of a conductive material such as a metal plate of stainless steel or the like. Therefore, when the arm part 2, the connection part 22B, and the end part 411 are in contact with each other, the electric circuit is connected and the arm part 2 is in an energized state.

[0062] On the other hand, when the arm part 2 and the end part 411 are separated and no longer in contact, the electric circuit is disconnected and no electricity flows through the arm part 2. In short, when a displacement of a predetermined value or more occurs at the boundary P3 due to the disengagement of the K segment P1 or the like, the end part 411 of the connection cable 41 of the circuit main body part 4 and the arm part 2 are separated, so that the electric circuit is in a disconnected state.

[0063] In the case of the detection device 1B of the second embodiment configured as described above, since one side of the rectangular connecting portion 22B in plan view and the end portion 411 of the circuit main body portion 4 can be parallel to each other over a long range, the arm portion 2 can be installed at a selected location where detection is desired. For example, when the K segment P1 is about to tilt and come out, by changing the position of the arm portion 2 within the range where one side of the connecting portion 22B and the end portion 411 of the circuit main body portion 4 are parallel, it becomes possible to easily perform operations such as replacement to the position where detection is desired.

[0064] Regarding other configurations and effects, since they are substantially the same as those in the above-described embodiment or other embodiments, the description thereof will be omitted.

Embodiment

[0065] Hereinafter, a detection device 1C in a form different from the detection devices 1, 1A, and 1B of the above-described embodiment and the first and second embodiments will be described with reference to FIGS. 9 and 10. Regarding the description of the parts that are the same as or equivalent to those described in the above-described embodiment or the first and second embodiments, the same terms or the same reference numerals will be used for the description.

[0066] In the above-described embodiment and the first and second embodiments, the detection devices 1, 1A, and 1B installed in the tunnel have been described. In the third embodiment, a detection device 1C installed on the earth retaining wall K4 will be described.

[0067] The earth retaining wall K4 constructed underground will support the exposed wall surface during excavation by installing the bulkhead K2 and the crossbar K1. The bulkhead K2 and the crossbar K1 formed of H-shaped steel or the like bring the end face of the crossbar K1 spanned between the earth retaining walls K4 into contact with the side surface of the bulkhead K2 arranged horizontally along the wall surface of the earth retaining wall K4.

[0068] That is, the boundary K3 between the crossbar K1 and the bulkhead K2 becomes a discontinuous portion. If the crossbar K1 is displaced, the earth retaining wall K4 will no longer be supported. Therefore, during the excavation work, it is necessary to detect the progress of the displacement of the boundary K3 in order to constantly monitor the movement of the crossbar K1.

[0069] Therefore, a cross-bridge portion 2C having an L-shaped side view is arranged so as to straddle the flange of the abdominal lift K2 and the flange of the shear K1. The cross-bridge portion 2C is respectively arranged with respect to the end portions 411 of the two connection cables 41 of the circuit main body portion 4, and by connecting the cross-bridge portions 2C, 2C to both ends of the connection portion 22C arranged on the abdominal lift K2, an electric circuit is formed.

[0070] FIG. 10 is an explanatory diagram schematically showing a detection state for detecting the displacement of the shear K1. When the cross-bridge portion 2C of the detection device 1C is arranged straddling the boundary P3, since the cross-bridge portion 2C is in contact with the end portion 411 of the connection cable 41, an electric circuit is formed and the light 3 is in a lit state.

[0071] On the other hand, when the shear K1 is displaced, for example, about 3 mm - 5 mm and moves downward, in other words, when the displacement of the boundary K3 progresses, the cross-bridge portion 2C and the end portion 411 of the circuit main body portion 4 are separated and the electric circuit is cut off, so the light 3 is in an extinguished state. If the light 3 that should be lit during normal operation is extinguished, it can be recognized that the displacement of the boundary K3 is progressing.

[0072] With the detection device 1C of the third embodiment configured as described above, even the progress of the displacement of the discontinuous portion existing other than the lining of the tunnel can be detected. Regarding other configurations and operational effects, since they are substantially the same as those in the above-described embodiment or other embodiments, the description is omitted.

Embodiment

[0073] Hereinafter, a detection device 1D in a form different from the detection devices 1, 1A - 1C of the above-described embodiment and the first to third embodiments will be described with reference to FIG. 11. Regarding the description of the same or equivalent parts as those described in the above-described embodiment or the first to third embodiments, the same terms or the same reference numerals will be used for the description.

[0074] In the above-described embodiments and Examples 1 and 2, the detection devices 1, 1A, and 1B installed in the tunnel were described, and in Example 3, the detection device 1C installed in the earth-retaining wall K4 was described. In this Example 4, the detection device 1D installed on the bridge will be described.

[0075] FIG. 11 is a diagram for explaining the configuration of the detection device 1D of Example 4. FIG. 11(a) is a schematic explanatory diagram, and FIG. 11(b) is a view seen from below in the direction of the arrow A-A of the side view. In this bridge, between the ends of the bridge girders B1 and B2 supported on the bridge pier B4, there is a joint B3 at the discontinuous portion.

[0076] In Example 4, in order to constantly monitor whether there are steps or the like at the joint B3, the detection device 1D is installed to detect, for example, the progress of the displacement of the joint B3 of about 3 mm to 5 mm. In the detection device 1D of Example 4, the bridging portion 2D is arranged on the lower surface side of the upper flange of the bridge girders B1 and B2 so as to straddle the joint B3.

[0077] The bridging portions 2D are respectively arranged with respect to the ends 411 of the two connection cables 41 of the circuit main body portion 4, and by connecting these bridging portions 2D and 2D to both ends of the connection portion 22D arranged at the end of the bridge girder B1, an electric circuit is formed.

[0078] With the detection device 1D of Example 4 configured as described above, even the progress of the displacement of the discontinuous portion such as the step generated at the joint B3 between the bridge girders B1 and B2 of the bridge can be detected. Regarding other configurations and effects, since they are substantially the same as those in the above-described embodiment or other examples, the description will be omitted.

[0079] As described above, the embodiments of the present invention have been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment or example, and design changes that do not depart from the gist of the present invention are included in the present invention.

[0080] For example, in the above-described embodiments and examples, the light 3 was described as the notification unit. However, the present invention is not limited to this, and a speaker unit that generates a buzzer sound or the like, a transmission unit that notifies the occurrence of disconnection of the electric circuit by email or the like, or the like can also be used as the notification unit.

Explanation of Signs

[0081] 1, 1A - 1D: Detection device 2: Arm part (bridging part) 2A, 2C, 2D: Bridging part 21: Fixing jig 3: Light (notification unit) 4: Circuit main body part 411: End part (end region) 5: Power supply unit M3: Discontinuous part P3: Boundary (discontinuous part) K3: Boundary (discontinuous part) B3: Joint (discontinuous part) T1: Tunnel circumferential direction

Claims

1. A detection device for detecting the progress of displacement at a discontinuous portion, comprising: a conductive bridging portion disposed across the discontinuous portion; a notification portion for notifying the energization state of the bridging portion; a circuit body portion for forming an electric circuit including the bridging portion; a power supply portion, wherein the electric circuit is characterized in that when a displacement of a predetermined value or more occurs at the discontinuous portion, the bridging portion and the circuit body portion are separated and disconnected.

2. The detection device according to claim 1, wherein the bridging portion is attached so as to be contactable with an arbitrary position in an end region of the circuit body portion.

3. The detection device according to claim 2, wherein the bridging portion is fixed by a fixing jig attached to a position adjacent to the discontinuous portion.

4. The discontinuous portion is a boundary of an arc-shaped segment of a tunnel, wherein the bridging portion is fixed to a segment to be detected for displacement, and has an arm portion that protrudes with respect to an end region of the circuit body portion attached to a segment adjacent in the circumferential direction of the tunnel. The detection device according to any one of claims 1 to 3.

5. The detection device according to any one of claims 1 to 3, wherein the notification portion is a light that lights up when the bridging portion is energized.

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