Monitoring device

Abstract

A monitoring device (10) comprises a control unit (12) that: sets a reference point for an underground structure that is a continuous body; calculates, on the basis of interferometric SAR measurement data (24), the difference in the amount of displacement of the ground in the up-down direction between the set reference point and a plurality of locations within an area in which the underground structure is buried; and determines the amount of relative displacement of the underground structure in the up-down direction at the plurality of locations.

Description

Monitoring Device

[0001] The present disclosure relates to a monitoring device.

[0002] Non-Patent Document 1 discloses that it is possible to obtain information on ground displacement by using data from interferometric SAR. "SAR" is an abbreviation for synthetic aperture radar.

[0003] Satoshi Fujiwara and two others, "Towards nationwide land subsidence detection using interferometric SAR", Geospatial Information Authority of Japan Bulletin, Geospatial Information Authority of Japan, October 1, 2005, Vol. 108

[0004] Information on vertical ground displacement from CORSs or observation wells could be used to determine whether or not countermeasures are necessary to prevent future deformation of underground structures. However, because measurement points are sparse and far from at least some of the linear structures, such as tunnels, there is a possibility that ground displacement occurring near the structures cannot be accurately assessed. Therefore, it is possible to use data from interferometric SAR. Compared to methods using GNSS, such as CORSs, interferometric SAR has the advantage that the observation time depends on the flight time of the SAR-equipped aircraft, such as the satellite's orbital period, but does not require equipment at the observation site and can observe a wide area at once. "GNSS" is an abbreviation for global navigation satellite system.

[0005] Underground structures such as tunnels are continuous, and obtaining information on step heights is useful for determining whether or not countermeasures are necessary. However, with conventional methods such as those disclosed in Non-Patent Document 1, the results of interferometric SAR indicate the amount of ground displacement at the same point, making it impossible to obtain information on step heights.

[0006] The purpose of this disclosure, made in consideration of such circumstances, is to obtain information useful for determining whether or not measures are necessary to deal with future deformation of underground structures.

[0007] A monitoring device in one embodiment sets a reference point for an underground structure, which is a continuum, and includes a control unit that calculates the difference in the amount of ground displacement in the vertical direction between the set reference point and multiple points within the area in which the underground structure is buried based on interferometric SAR measurement data, thereby determining the relative amount of displacement of the underground structure in the vertical direction at the multiple points.

[0008] According to the present disclosure, it is possible to obtain information useful for determining whether or not measures are necessary to deal with future deformation of underground structures.

[0009] 1 is a block diagram showing the configuration of a monitoring device according to an embodiment; FIG. 2 is a diagram showing an example of an evaluation of relative displacement occurring around an underground structure; FIG. 3 is a schematic diagram of an underground structure which is a continuum; FIG. 4 is a graph showing an example of an interferometric SAR result; FIG. 5 is a graph showing an example of displacement evaluation; FIG. 6 is a flowchart showing the operation of the monitoring device; FIG. 7 is a diagram showing an example of countermeasures; and FIG. 8 is a graph showing a modified example of displacement evaluation.

[0010] An embodiment will be described below with reference to the drawings.

[0011] In each drawing, the same or corresponding parts are denoted by the same reference numerals. In the description of this embodiment, the description of the same or corresponding parts will be omitted or simplified as appropriate.

[0012] The outline of this embodiment will be described with reference to FIGS.

[0013] The monitoring device 10 is a device that monitors the amount of vertical displacement of each part of the underground structure 30, which is a continuous body. The monitoring device 10 may be a general-purpose computer such as a PC, a server computer such as a cloud server, or a dedicated computer. "PC" is an abbreviation for personal computer.

[0014] The underground structure 30 is, for example, a tunnel such as a cable tunnel. In this embodiment, the underground structure 30 includes a manhole.

[0015] The monitoring device 10 sets a reference point 31 on the underground structure 30. Based on the interferometric SAR measurement data 24, the monitoring device 10 determines the amount of relative displacement from the reference point 31 of the ground at each position of the underground structure 30. The monitoring device 10 calculates the amount of displacement obtained by accumulating the amount of relative displacement for the number of interferometric SAR measurements as the amount of relative displacement of each part of the underground structure 30. Alternatively, the monitoring device 10 may calculate the amount of displacement of each part of the underground structure 30 by adding the amount of relative displacement from the reference point 31 of the ground at each corresponding position from the time the underground structure 30 was newly constructed to the time of the first interferometric SAR measurement to the amount of displacement obtained by accumulating the amount of relative displacement from the reference point 31 of the ground at each position of the underground structure 30 for the number of interferometric SAR measurements.

[0016] According to this embodiment, the displacement of the underground structure 30, which is a continuous body, can be correctly evaluated.

[0017] In the example shown in Figure 2, the underground structure 30 is a tunnel. The position of the tunnel's iron cover is set as a reference point 31, and information on the level difference in the tunnel can be obtained by using the results of interferometric SAR to evaluate the displacement occurring in the tunnel as a relative displacement from the reference point 31. This information can then be used to take measures in advance to prevent future deformation, thereby maintaining the integrity of the tunnel.

[0018] The configuration of a monitoring device 10 according to this embodiment will be described with reference to FIG.

[0019] The monitoring device 10 includes a storage unit 11 , an input unit 12 , a control unit 13 , and an output unit 14 .

[0020] The storage unit 11 includes at least one semiconductor memory, at least one magnetic memory, at least one optical memory, or any combination thereof. The semiconductor memory is, for example, a RAM, a ROM, or a flash memory. "RAM" is an abbreviation for random access memory. "ROM" is an abbreviation for read only memory. RAM is, for example, an SRAM or a DRAM. "SRAM" is an abbreviation for static random access memory. "DRAM" is an abbreviation for dynamic random access memory. ROM is, for example, an EEPROM. "EEPROM" is an abbreviation for electrically erasable programmable read only memory. Flash memory is, for example, an SSD. "SSD" is an abbreviation for solid-state drive. Magnetic memory is, for example, an HDD. "HDD" is an abbreviation for hard disk drive. The storage unit 11 functions, for example, as a main storage device, an auxiliary storage device, or a cache memory. The storage unit 11 stores information used in the operation of the monitoring device 10 and information obtained by the operation of the monitoring device 10. For example, the storage unit 11 may store map information 21, equipment information 22, location information 23, and measurement data 24.

[0021] The input unit 12 includes at least one communication module. The communication module is, for example, a module compatible with a wired LAN communication standard such as Ethernet (registered trademark), a wireless LAN communication standard such as IEEE 802.11, or a mobile communication standard such as LTE, 4G, or 5G. "LAN" is an abbreviation for local area network. "IEEE" is an abbreviation for Institute of Electrical and Electronics Engineers. "LTE" is an abbreviation for Long Term Evolution. "4G" is an abbreviation for 4th generation. "5G" is an abbreviation for 5th generation. The input unit 12 receives information used in the operation of the monitoring device 10 from other devices via a network. The network may include, for example, the Internet, at least one WAN, at least one MAN, or any combination thereof. "WAN" is an abbreviation for wide area network. "MAN" is an abbreviation for metropolitan area network. The network may include at least one wireless network, at least one optical network, or any combination thereof. The wireless network may be, for example, an ad hoc network, a cellular network, a wireless LAN, a satellite communication network, or a terrestrial microwave network. For example, the input unit 12 receives map information 21, facility information 22, location information 23, and measurement data 24 from other devices.

[0022] The input unit 12 may include an input device. The input device may be, for example, a physical key, a capacitive key, a pointing device, a touch screen integrated with a display, a camera, or a microphone. The input device accepts an operation to input information used in the operation of the monitoring device 10. The input device may be connected to the monitoring device 10 as an external input device instead of being provided in the monitoring device 10. The connection interface may be an interface compatible with standards such as USB, HDMI (registered trademark), or Bluetooth (registered trademark). "USB" is an abbreviation for Universal Serial Bus. "HDMI (registered trademark)" is an abbreviation for High-Definition Multimedia Interface. For example, the input unit 12 may accept an operation to input map information 21, facility information 22, location information 23, and measurement data 24.

[0023] The control unit 13 includes at least one processor, at least one programmable circuit, at least one dedicated circuit, or any combination thereof. The processor is a general-purpose processor such as a CPU or GPU, or a dedicated processor specialized for specific processing. "CPU" is an abbreviation for central processing unit. "GPU" is an abbreviation for graphics processing unit. An example of the programmable circuit is an FPGA. "FPGA" is an abbreviation for field-programmable gate array. An example of the dedicated circuit is an ASIC. "ASIC" is an abbreviation for application specific integrated circuit. The control unit 13 executes processing related to the operation of the monitoring device 10 while controlling each part of the monitoring device 10.

[0024] The output unit 14 includes a communication module common to the input unit 12. The output unit 14 transmits information obtained by the operation of the monitoring device 10 to other devices via a network. For example, the output unit 14 transmits a countermeasure implementation necessity 41 to other devices.

[0025] The output unit 14 may include an output device. The output device is, for example, a display or a speaker. The display is, for example, an LCD or an organic EL display. "LCD" is an abbreviation for liquid crystal display. "EL" is an abbreviation for electroluminescent. The output device outputs information obtained by the operation of the monitoring device 10. The output device may be connected to the monitoring device 10 as an external output device instead of being provided in the monitoring device 10. The connection interface may be an interface compatible with standards such as USB, HDMI (registered trademark), or Bluetooth (registered trademark). For example, the output unit 14 may display the necessity of implementing countermeasures 41 on a screen or output it as audio.

[0026] The functions of the monitoring device 10 are realized by executing a program according to this embodiment on a processor serving as the control unit 13. That is, the functions of the monitoring device 10 are realized by software. The program causes a computer to execute the operations of the monitoring device 10, thereby causing the computer to function as the monitoring device 10. That is, the computer functions as the monitoring device 10 by executing the operations of the monitoring device 10 in accordance with the program.

[0027] The program can be stored on a non-transitory computer-readable medium. Examples of the non-transitory computer-readable medium include flash memory, magnetic recording devices, optical disks, magneto-optical recording media, and ROMs. The program can be distributed by selling, transferring, or lending portable media such as SD cards, DVDs, or CD-ROMs that store the program. "SD" is an abbreviation for Secure Digital. "DVD" is an abbreviation for digital versatile disc. "CD-ROM" is an abbreviation for compact disc read only memory. The program can also be distributed by storing it in the storage of a server and transferring it from the server to another computer. The program can also be provided as a program product.

[0028] A computer temporarily stores a program stored on a portable medium or transferred from a server in its main storage device. The computer then reads the program stored in the main storage device with its processor and executes processing in accordance with the read program. The computer may also read the program directly from the portable medium and execute processing in accordance with the program. The computer may also execute processing in accordance with the received program each time a program is transferred from the server to the computer. Processing may also be executed using a so-called ASP-type service that realizes functions simply by issuing execution instructions and obtaining results, without transferring the program from the server to the computer. "ASP" is an abbreviation for application service provider. A program is information used for processing by a computer and includes something equivalent to a program. For example, data that is not a direct instruction to a computer but has properties that define computer processing falls under the category of "something equivalent to a program."

[0029] Some or all of the functions of the monitoring device 10 may be realized by a programmable circuit or a dedicated circuit as the control unit 13. In other words, some or all of the functions of the monitoring device 10 may be realized by hardware.

[0030] The map information 21 includes, for example, information about the position of the iron cover. Based on the map information 21, the control unit 13 sets a reference point 31 for the underground structure 30 as shown in FIG.

[0031] The facility information 22 includes, for example, information about the tunnel structure and joints. The location information 23 includes, for example, information such as coordinates obtained from a GIS or other system. "GIS" is an abbreviation for geographic information system. Based on the facility information 22 and the location information 23, the control unit 13 identifies multiple points 32 within the area where the underground structure 30 is buried, as shown in FIG. 3 . The multiple points 32 are locations that are the subject of relative displacement calculation, such as tunnel joints.

[0032] The measurement data 24 includes the measurement results of the interferometric SAR as shown in FIG. ０ Ｓ -d ０ ｌ is the displacement of the ground in the vertical direction of the reference point 31. １ Ｓ -d １ ｌ is the vertical displacement of the ground at the point closest to the reference point 31 among the multiple points 32. ｉ Ｓ -d ｉ ｌ is the vertical displacement of the ground at the point among the plurality of points 32 that is the i-th closest to the reference point 31. The control unit 13 calculates the difference in the vertical displacement of the ground between the reference point 31 and the plurality of points 32 based on the measurement data 24, and obtains the relative vertical displacement of the underground structure 30 at the plurality of points 32 as shown in FIG. 5. In FIG. 5, d １ Ｓ -d ０ Ｓis the relative displacement of the underground structure 30 in the vertical direction at the point closest to the reference point 31 among the multiple points 32. ｉ Ｓ -d ０ Ｓ is the relative displacement of the underground structure 30 in the vertical direction at the point among the multiple points 32 that is the i-th closest to the reference point 31.

[0033] The control unit 13 evaluates the amount of relative displacement of the underground structure 30 in the vertical direction at the multiple points 32 as the magnitude of the step between the multiple points 32, thereby determining whether or not to implement countermeasures such as flexible joints. For example, if the amount of relative displacement of the underground structure 30 in the vertical direction at at least one of the multiple points 32 exceeds a threshold, the control unit 13 determines that a large fluctuation is expected at that at least one point and therefore that countermeasures are necessary. The threshold is set according to the tolerance of the joint rubber, such as 20 millimeters. The control unit 13 transmits the result of the determination as countermeasure implementation necessity 41 to the output unit 14, displays it on a screen, or outputs it as audio. The control unit 13 may also transmit the amount of relative displacement of the underground structure 30 in the vertical direction at the multiple points 32 to the output unit 14, displays it on a screen, or outputs it as audio, and leave the determination of whether or not to implement countermeasures to a human or other device.

[0034] In this embodiment, as shown in FIG. 5, the influence of temporal changes is obtained as a step from the reference point 31. As a result, it becomes possible to prioritize affected areas. The measurement values ​​of the interferometric SAR may be stacked to reduce errors. That is, multiple analysis results may be averaged to obtain the fluctuation rate. This makes it possible to remove noise due to water vapor.

[0035] In this embodiment, the iron cover on the ground may be used as the reference point 31, and the position information 23 and the measurement data 24 may be superimposed. By using information about the position of the iron cover on the ground, it is possible to align the shaft position without any deviation. It is also possible to utilize the difference in electromagnetic wave reflectivity due to the difference in materials between the iron cover and the asphalt. In this way, correct alignment is possible even when it is difficult to distinguish using optical satellite images.

[0036] For example, if a displacement occurs in a tunnel, the displacement will be concentrated in the rubber joints at the tunnel joints. If a large step occurs, cracks will occur in the rubber joints, which may lead to water leakage. According to this embodiment, by installing repair materials that follow the displacement at tunnel joints where a certain level of displacement is expected based on the annual relative displacement amount identified by interferometric SAR, it becomes possible to take proactive measures against water leakage. This method can also be applied to existing underground tunnels. It is possible to narrow down the areas with large displacement and perform a quantitative evaluation.

[0037] In this embodiment, information about the location of tunnels plotted on existing maps can be utilized. Data on ground deformation obtained from interferometric SAR can be combined with information about the location of tunnels to perform an evaluation, making it possible to identify areas where deformation is large. For joints where large deformation is expected, flexible joints can be installed, allowing for proactive measures to be taken against flooding due to steps. It is possible to pinpoint areas where large deformation is expected, and select areas for countermeasures through quantitative comparison.

[0038] The operation of the monitoring device 10 according to this embodiment will be described with reference to Fig. 6. The operation described below corresponds to the monitoring method according to this embodiment. That is, the monitoring method according to this embodiment includes at least steps S1 to S6 shown in Fig. 6.

[0039] In S1, the control unit 13 sets a reference point 31 for the underground structure 30, which is a continuum. In this embodiment, the control unit 13 sets the reference point 31 based on map information 21. The map information 21 includes information regarding the positions of manhole covers.

[0040] In S2, the control unit 13 identifies a plurality of points 32 within the range where the underground structure 30 is buried, based on the facility information 22 and the location information 23.

[0041] In S3, the control unit 13 calculates the difference in the amount of ground displacement in the vertical direction between the reference point 31 set in S1 and the multiple points 32 specified in S2 based on the interferometric SAR measurement data 24, thereby determining the amount of relative displacement of the underground structure 30 in the vertical direction at the multiple points 32. Specifically, the control unit 13 accumulates the differences in the amount of ground displacement in the vertical direction between the reference point 31 and the multiple points 32 for the number of interferometric SAR measurements based on the measurement data for the number of interferometric SAR measurements, thereby determining the amount of relative displacement of the underground structure 30 in the vertical direction at the multiple points 32.

[0042] In S4, the control unit 13 compares the relative displacement calculated in S3 with a threshold value for the multiple points 32 identified in S2 to determine whether or not measures such as flexible joints as shown in Fig. 7 are required. In Fig. 7, the lower side corresponds to the natural ground side, and a waterproof sheet 51 and a resin 52 are attached by fastening them together with fixing bolts 53 on the side opposite the natural ground side.

[0043] If it is determined in S4 that no countermeasures are required for any of the locations, the process proceeds to step S5. If it is determined that countermeasures are required for at least one location, the process proceeds to step S6.

[0044] In S5, the control unit 13 transmits the result of the determination that the implementation of the countermeasure is unnecessary to the output unit 14, displays it on the screen, or outputs it as voice as a countermeasure implementation necessity 41. Thereafter, the steps from S3 onwards are performed again as needed or periodically.

[0045] In S6, the control unit 13 transmits, displays on the screen, or outputs by voice, information about which points require countermeasure implementation as countermeasure implementation necessity 41 to the output unit 14. Thereafter, the steps from S3 onwards are performed again as needed or periodically.

[0046] As a modified example, in addition to the interferometric SAR measurement values, the amount of displacement since the initial construction of the underground structure 30 may be taken into consideration. The amount of displacement since the initial construction may be evaluated, for example, from information on past vertical ground displacement at electronic reference points or observation wells.

[0047] In this modification, the control unit 13 estimates the difference in the amount of vertical ground displacement between the reference point 31 and the multiple points 32 from the time when the underground structure 30 was newly constructed to the time when the first interferometric SAR measurement was performed, based on past information. The past information includes information on crustal movements in the area where the underground structure 30 is buried. In S3 shown in Fig. 6, the control unit 13 calculates the sum of the difference accumulated for the number of interferometric SAR measurements and the estimated difference as the amount of relative vertical displacement of the underground structure 30 at the multiple points 32, as shown in Fig. 8. In Fig. 8, d １ Ｓ -d ０ Ｓ and d ｉ Ｓ -d ０ Ｓ is the same as the example shown in FIG. １ is the difference in the amount of vertical ground displacement between the reference point 31 and the point among the multiple points 32 that is closest to the reference point 31 from the time when the underground structure 30 is newly constructed until the time when the interferometric SAR is first measured. １ is the relative displacement of the underground structure 30 in the vertical direction at the point closest to the reference point 31 among the multiple points 32 before the interferometric SAR measurement. ｉ is the difference in the amount of vertical ground displacement between the reference point 31 and the i-th closest point to the reference point 31 among the multiple points 32 from the time when the underground structure 30 is newly constructed until the time of the first measurement of the interferometric SAR. ｉ is the amount of relative displacement of the underground structure 30 in the vertical direction at the point among the multiple points 32 that is the i-th closest to the reference point 31 before the interferometric SAR measurement. Therefore, if the number of interferometric SAR measurements is one, the amount of relative displacement calculated in S3 for the point among the multiple points 32 that is the closest to the reference point 31 is d １ Ｓ -d ０ Ｓ +h １ The relative displacement amount calculated in S3 for the point closest to the reference point 31 among the multiple points 32 is d ｉ Ｓ -d ０ Ｓ +h ｉ is.

[0048] The present disclosure is not limited to the above-described embodiments. For example, two or more blocks shown in the block diagram may be integrated, or one block may be divided. Two or more steps shown in the flowchart may be executed in parallel or in a different order, instead of being executed in chronological order as described, depending on the processing capabilities of the device executing each step, or as needed. Other modifications are possible within the scope of the present disclosure.

[0049] REFERENCE SIGNS LIST 10 Monitoring device 11 Memory unit 12 Control unit 13 Input unit 14 Output unit 21 Map information 22 Facility information 23 Location information 24 Measurement data 30 Underground structure 31 Reference point 32 Multiple points 41 Necessity of countermeasure implementation 51 Water stop sheet 52 Resin 53 Fixing bolt

Claims

1. A monitoring device that sets a reference point for a continuous underground structure, and has a control unit that calculates the difference in the amount of ground displacement in the vertical direction between the set reference point and multiple points within the area where the underground structure is buried based on interferometric SAR measurement data, thereby determining the relative displacement of the underground structure in the vertical direction at the multiple points.

2. The monitoring device of claim 1, wherein the control unit calculates the relative displacement by accumulating the difference in the amount of ground displacement in the vertical direction between the reference point and the multiple points based on the measurement data for the number of interferometric SAR measurements.

3. The control unit estimates the difference in the amount of ground displacement in the vertical direction between the reference point and the multiple points from the time the underground structure is newly constructed to the time the first interferometric SAR measurement is made based on information regarding crustal movements in the area where the underground structure is buried, and calculates the relative displacement as the sum of the accumulated difference and the estimated difference.

4. A monitoring device as described in any one of claims 1 to 3, wherein the underground structure includes a manhole, and the control unit sets the reference point based on information regarding the position of the manhole cover.

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