JP2018028443A - Management method and management device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a management method and management device capable of simply detecting abnormality of a PC steel stranded wire of a PC structure.SOLUTION: A management method for managing a PC stranded wire with an optical fiber, which has a PC steel stranded wire formed by stranding a plurality of PC steel element wires and an optical fiber installed along a stranded portion of the PC steel stranded wire, comprises a loss measurement step (step S30-step S32) of measuring transmission loss of scattered light incident into the optical fiber; and an abnormality detection step (step S33-step S35) of detecting abnormality of the PC steel stranded wire with the optical fiber, based on the transmission loss measured in the loss measurement step.SELECTED DRAWING: Figure 9

Description

  The present invention relates to a management method and a management apparatus for managing a PC steel stranded wire with an optical fiber.

  Conventionally, in a structure in which a PC steel stranded wire is fixed in a state where tension is introduced in advance (hereinafter also referred to as a “PC structure”), the strain of the PC steel stranded wire using a load cell or a magnetostrictive sensor is used. PC steel stranded wire management methods are known in which an abnormality of a PC steel stranded wire is detected based on the measured strain. With such a management method, it is possible to measure the strain at the location where the sensor is installed, but it is difficult to grasp the strain along the PC steel stranded wire.

  In recent years, in this technical field, by using a PC steel stranded wire with an optical fiber, it has become possible to grasp the strain along the PC steel stranded wire by measuring the strain of the optical fiber. For example, Patent Literature 1 describes a strain detection system that measures strain of an optical fiber based on a frequency shift of Brillouin scattered light of incident light incident on the optical fiber.

JP 2000-46527 A

  In the strain detection system described in Patent Document 1, for example, a BOTDR (Brillouin Optical Time Domain Reflectometer) is required as a measuring instrument for measuring strain or the like of an optical fiber with Brillouin scattered light. However, it is difficult to say that BOTDR is suitable for regular management of PC steel stranded wire in a PC structure in service due to the fact that the equipment is expensive. Therefore, it is desired to detect an abnormality of the PC steel stranded wire of the PC structure more simply.

  Then, an object of this invention is to provide the management method and management apparatus which can detect the abnormality of PC steel strand wire of PC structure simply.

  A management method according to the present invention includes a PC steel twisted wire formed by twisting a plurality of PC steel strands, and an optical fiber installed along a twist line of the PC steel twisted wire. A management method for managing steel stranded wire, including a loss measurement step for measuring a transmission loss of scattered light incident on an optical fiber, and an abnormality in a PC steel stranded wire based on the transmission loss measured in the loss measurement step. And an abnormality detection step for detecting.

  In this management method, by measuring the transmission loss in the loss measurement step, the abnormality of the PC steel stranded wire can be detected in the abnormality detection step based on the measured transmission loss. Therefore, since the simple measuring instrument which measures a transmission loss can be utilized for management of PC steel twisted wire, it becomes possible to detect abnormally the PC steel twisted wire of PC structure easily.

  In the management method according to the present invention, in the abnormality detection step, an abnormality in the PC steel stranded wire may be detected based on the correlation between the transmission loss and the strain in the PC steel stranded wire. In this case, the distortion of the PC steel stranded wire can be estimated based on the correlation in addition to the measured transmission loss, and the abnormality of the PC steel stranded wire can be detected in the abnormality detection step based on the estimated distortion of the PC steel stranded wire.

  The management method according to the present invention further includes a relationship acquisition step of acquiring a correlation, and in the abnormality detection step, distortion is acquired from the transmission loss based on the correlation acquired in the relationship acquisition step, and based on the acquired distortion An abnormality of the PC steel stranded wire may be detected. In this case, the acquired correlation can be used in the abnormality detection step by acquiring the correlation between the transmission loss and the distortion in advance in the relationship acquiring step.

  In the management method according to the present invention, in the relationship acquisition step, the transmission loss and the PC steel twist are measured by measuring the transmission loss according to the tension introduced into the PC steel twisted wire during the construction of the PC steel twisted wire with optical fiber. The correlation with the strain of the wire is obtained, and in the loss measurement step, the reference transmission loss that is the transmission loss before the use of the PC steel stranded wire with optical fiber and the transmission loss during the use of the PC steel stranded wire with the optical fiber are obtained. A certain monitoring transmission loss is measured, and in the anomaly detection step, a strain change is acquired based on the correlation acquired in the relationship acquisition step, the reference transmission loss, and the monitoring transmission loss, and the acquired strain change is obtained. An abnormality of the PC steel stranded wire may be detected based on the above. In this case, in the relationship acquisition step, the transmission loss corresponding to the tensile force introduced into the PC steel stranded wire during the construction of the PC steel stranded wire with optical fiber is measured, so that the correlation specific to the PC structure can be acquired. . Further, in the abnormality detection step, according to the reference transmission loss before in-service based on the correlation specific to the PC structure acquired in the relationship acquisition step, and the reference transmission loss and monitoring transmission loss measured in the loss measurement step. The strain corresponding to the measured transmission loss and the monitoring transmission loss during service can be calculated, and the change in strain based on the pre-service can be obtained. Therefore, it is possible to accurately detect an abnormality in the PC steel stranded wire with reference to before use.

  In the management method which concerns on this invention, you may further provide the alerting | reporting step which alert | reports the information regarding the abnormality of PC steel twisted wire detected by the abnormality detection step. In this case, the information regarding the abnormality of the detected PC steel twisted wire can be easily recognized by the notification unit.

  Moreover, this invention can also be grasped | ascertained also as invention of a management apparatus, and this management apparatus is along the twist line of the PC steel stranded wire formed by twisting the some PC steel strand, and the twist of PC steel stranded wire. Is a management device for managing a PC steel stranded wire with an optical fiber, and a measuring unit that measures a transmission loss of scattered light incident on the optical fiber, and is measured by the measuring unit An abnormality detection unit that detects an abnormality of the PC steel stranded wire based on the transmission loss.

  In this management device, the abnormality of the PC steel stranded wire can be detected by the abnormality detection unit based on the measured transmission loss by measuring the transmission loss by the measurement unit. Therefore, since the simple measuring instrument which measures a transmission loss can be utilized for management of PC steel twisted wire, it becomes possible to detect abnormally the PC steel twisted wire of PC structure easily.

  In the management device according to the present invention, the abnormality detection unit may detect an abnormality in the PC steel stranded wire based further on the correlation between the transmission loss and the strain in the PC steel stranded wire. In this case, the strain of the PC steel stranded wire can be estimated based on the measured transmission loss and the correlation, and the abnormality of the PC steel stranded wire can be detected by the abnormality detection unit based on the estimated strain of the PC steel stranded wire.

  In the management apparatus which concerns on this invention, you may further provide the alerting | reporting part which alert | reports the information regarding the abnormality of the PC steel twisted wire detected by the abnormality detection part. In this case, the information regarding the abnormality of the detected PC steel twisted wire can be easily recognized by the notification unit.

  In the management device according to the present invention, the PC steel stranded wire with an optical fiber is in contact with the fixing portion and the base portion through which the PC steel stranded wire with an optical fiber is inserted; It is fixed to the fixing part by a fixing part structure including a socket part through which the PC steel stranded wire is inserted, and a wedge part inserted from the rear between the inner wall surface of the socket part and the PC steel stranded wire with optical fiber. It may be. In this case, it is possible to easily detect an abnormality in the PC steel stranded wire of the PC structure by using a transmission loss generated by pressing the PC steel stranded wire with an optical fiber by the inserted wedge portion.

  ADVANTAGE OF THE INVENTION According to this invention, the management method and management apparatus which can detect the abnormality of the PC steel strand of a PC structure simply can be provided.

FIG. 1A is a perspective view of an example of a PC steel stranded wire with an optical fiber to which a management method and a management apparatus according to an embodiment are applied. FIG. 1B is a perspective view of an example of an optical fiber. FIG. 2 is a block diagram illustrating a configuration example of a management apparatus when measuring strain of an optical fiber. FIG. 3 is a block diagram illustrating a configuration example of a management apparatus when measuring a transmission loss of an optical fiber. FIG. 4 is a graph illustrating strain based on Brillouin scattered light. FIG. 5 is a graph illustrating the intensity of Rayleigh scattered light. FIG. 6 is a graph illustrating the relative relationship between the strain of FIG. 4 and the strength of FIG. FIG. 7 is a flowchart illustrating processing during construction of the management method according to the first embodiment. FIG. 8 is a flowchart illustrating processing immediately before and during service of the management method according to the first embodiment. FIG. 9 is a flowchart illustrating processing immediately before and during service of the management method according to the second embodiment. FIG. 10 is another graph illustrating strain based on Brillouin scattered light. FIG. 11 is another graph illustrating the intensity of Rayleigh scattered light. FIG. 12 is a graph illustrating the relative relationship between the strain of FIG. 10 and the strength of FIG. FIG. 13 is a graph illustrating the relationship between the strain in FIG. 10 and the difference in strength between the two points in FIG. 11. FIG. 14 is a partial cross-sectional view of an example of a fixing unit structure for fixing the PC steel stranded wire with optical fiber of FIG. FIG. 15 is an exploded perspective view of the socket portion and the wedge portion of the fixing portion structure shown in FIG.

  Hereinafter, an embodiment of a management method and a management device according to the present invention will be described in detail with reference to the drawings. Note that in the description, the same elements or elements having the same function may be denoted by the same reference numerals, and redundant description will be omitted. In the following description, when terms having front and rear concepts such as “front”, “rear”, “front end”, “rear end” are used, the upper side in FIG. 14 is the rear side, and the lower side in FIG. And

  The management method and management device according to the present embodiment are for managing a PC structure using a PC steel stranded wire 1 with an optical fiber. Management of the PC structure means detecting whether or not an abnormality has occurred in the PC steel stranded wire, which is the key to the durability of the PC structure. As an abnormality of the PC steel stranded wire, for example, fluctuation (for example, decrease) in the tension of the PC steel stranded wire fixed to the PC structure in a state where the tension is previously introduced. In the management of the PC structure by the management method and the management apparatus according to the present embodiment, the PC steel twist is performed based on the transmission loss (transmission loss) of light in the optical fiber using the PC steel twisted wire 1 with an optical fiber. Indirectly obtain the fluctuation of the tension of the line. The transmission loss means the degree of attenuation of the transmission intensity of light transmitted through the optical fiber.

  First, the PC steel stranded wire 1 with an optical fiber will be described. (A) of Drawing 1 is a perspective view of PC steel twisted wire 1 with an optical fiber to which the management method and management device concerning one embodiment are applied. FIG. 1B is a perspective view of an example of an optical fiber. FIG. 2 is a block diagram illustrating a configuration example of a management apparatus when measuring strain of an optical fiber. FIG. 3 is a block diagram illustrating a configuration example of a management apparatus when measuring a transmission loss of an optical fiber.

  As shown in FIG. 1 (a), an optical fiber-attached PC steel stranded wire 1, a PC steel stranded wire 3, and an optical fiber member (optical fiber) 20 attached to the surface of the PC steel stranded wire 3, Have The PC steel stranded wire 3 is a stranded wire formed by twisting a plurality of PC steel strands 4 having the same diameter made of, for example, a strand steel material. As an example, the PC steel stranded wire 3 is formed by twisting seven PC steel strands 4. On the surface of the PC steel stranded wire 3, a twist line 3a of the PC steel stranded wire 3 is formed as a valley between two adjacent PC steel strands 4, 4. The valley is inclined at a predetermined angle on the surface of the PC steel stranded wire 3 with respect to the bus bar extending in parallel with the axis A of the PC steel stranded wire 3 and extends in a spiral shape with the axis A as the center. In other words, the PC steel stranded wire 3 has a helical twist 3a. A coating (sheath) for preventing corrosion or the like is provided on the surface of the PC steel stranded wire 3.

  As shown in FIG. 1B, the optical fiber members 20 are respectively installed along two of the twist lines 3a, for example. Each optical fiber member 20 is installed so as to be embedded in the valley, and extends in a spiral manner between the adjacent PC steel wires 4, 4 along the adjacent PC steel wires 4, 4. It is installed to do. The optical fiber member 20 includes an optical fiber main body 21 embedded in the center of a surface orthogonal to the extending direction, and a resin filler 22 surrounding the optical fiber main body 21. The optical fiber main body 21 has an optical fiber strand 23 and a coating 24 that covers the optical fiber strand 23. The coating 24 is made of, for example, a polyamide-based material. The filler 22 is a member that fills a gap between the PC steel strands 4 and 4 and the optical fiber main body 21 in the twist 3a where the optical fiber member 20 is installed, and is made of, for example, polyethylene resin.

  The PC steel stranded wire with optical fiber as described above is fixed to the PC structure while tension is introduced into the PC steel stranded wire with optical fiber 1 for reinforcement of the PC structure. At this time, since the optical fiber member 20 is disposed in the stranded line 3a, when the PC steel stranded wire 3 is distorted, the optical fiber strand 23 of the optical fiber member 20 is also distorted. Moreover, in the optical fiber strand 23, the fall of the intensity | strength of the light transmitted through the optical fiber strand 23 (henceforth a "transmission loss" only) may arise. The distortion and transmission loss of the optical fiber 23 are measured using the management device 70 as follows.

  As shown in FIG. 2, in order to measure the strain of the optical fiber 23, the management device 70 is connected to the PC steel stranded wire 1 with an optical fiber via a measuring instrument 80A. For example, BOTDR can be used as the measuring instrument 80A. BOTDR is a measuring instrument for measuring the strain and temperature of the optical fiber 23 using Brillouin scattered light. Brillouin scattered light is one of various scattered light that is generated when pulsed light incident on the optical fiber strand 23 travels through the optical fiber strand 23. Brillouin scattered light is scattered light that depends on strain and temperature changes among various types of scattered light.

  The measuring instrument 80A includes an optical signal transmitter 81A, a spectroscopic unit 82A, a detector 83A, and an optical signal receiver 84A. The optical signal transmitter 81A includes a light source and a pulse generator. The optical signal transmitter 81 </ b> A generates pulsed light and causes the generated pulsed light to enter the optical fiber strand 23. The spectroscopic unit 82 </ b> A splits the Brillouin scattered light returned from the optical fiber strand 23. The detector 83A detects the Brillouin scattered light spectrally separated by the spectroscopic unit 82A, for example, by an optical heterodyne method. The optical signal receiving unit 84A measures a frequency shift generated in the detected Brillouin scattered light. For example, Yokogawa AQ8603 can be used as the measuring instrument 80A.

  A tension sensor 76 is connected to the PC steel stranded wire with optical fiber 1. The tension sensor 76 measures the tension introduced into the PC steel stranded wire 1 with an optical fiber. The tension sensor 76 inputs information about the measured tension to the management device 70.

  As shown in FIG. 3, in order to measure the transmission loss of the optical fiber strand 23, the management device 70 is connected to the PC steel stranded wire 1 with an optical fiber via a measuring instrument 80B. As the measuring instrument 80B, for example, an OTDR (Optical Time Domain Reflectometer) can be used. The OTDR is a measuring instrument for measuring the transmission loss of the optical fiber 23 based on the intensity of Rayleigh scattered light. Rayleigh scattered light is one of various types of scattered light that is generated when pulsed light incident on the optical fiber strand 23 travels through the optical fiber strand 23. Rayleigh scattered light is scattered light having the same frequency as incident light among various scattered light, and the light intensity depending on the loss of each part of the optical fiber strand 23.

  The measuring instrument 80B includes an optical signal transmitting unit 81B, a spectroscopic unit 82B, and an optical signal receiving unit 83B. The optical signal transmitter 81B includes a light source and a pulse generator. The optical signal transmission unit 81B generates pulsed light and causes the generated pulsed light to enter the optical fiber strand 23. The spectroscopic unit 82B splits the Rayleigh scattered light returned from the optical fiber strand 23. The optical signal receiving unit 83B measures the intensity of the scattered Rayleigh scattered light. In the measuring instrument 80 </ b> B, the pulsed light generated by the optical signal transmission unit 81 </ b> B including the light source and the pulse generator is incident on the optical fiber strand 23. The returned Rayleigh scattered light is split by the spectroscopic unit 82B and received by the optical signal receiving unit 83B. The measuring instrument 80B measures the intensity of Rayleigh scattered light received by the optical signal receiving unit 83B.

  A tension sensor 76 is connected to the PC steel stranded wire with optical fiber 1. The tension sensor 76 detects the tension introduced into the PC steel stranded wire 1 with an optical fiber. The tension sensor 76 inputs information regarding the detected tension to the management device 70. Note that the tension sensor 76 may be omitted during use of the PC steel stranded wire 1 with an optical fiber.

  The management device 70 detects an abnormality in the PC steel stranded wire 3 based on at least the transmission loss of the optical fiber strand 23. The management device 70 is, for example, a computer constituted by a CPU (Central Processing Unit), a ROM (Read Only Memory, and a RAM (Random Access Memory), and a control program for controlling the management device 70 is stored in the ROM. The CPU controls the management device 70 based on the control program stored in the ROM, and the RAM functions as a work memory when the CPU executes the control program stored in the ROM.

  The management device 70 includes a measurement unit 71, a relationship acquisition unit 72, a storage unit 73, an abnormality detection unit 74, and a display unit (notification unit) 75 as functional configurations.

  The measuring unit 71 measures the strain of the optical fiber 23 based on the frequency shift of the Brillouin scattered light received by the optical signal receiving unit 84A of the measuring instrument 80A. The measuring unit 71 measures the transmission loss of the optical fiber 23 based on the intensity of the Rayleigh scattered light received by the optical signal receiving unit 83B of the measuring instrument 80B. The transmission loss can be obtained by, for example, the difference between the intensity of Rayleigh scattered light at a predetermined position of the optical fiber strand 23 and the intensity of Rayleigh scattered light at a position different from the predetermined position of the optical fiber strand 23. The measuring unit 71 measures the tension introduced into the PC steel stranded wire with optical fiber 1 based on the information about the tension input by the tension sensor 76.

  During construction of the PC steel stranded wire 1 with an optical fiber, the measuring unit 71 is an optical fiber corresponding to the tension force introduced into the PC steel stranded wire 1 with an optical fiber stepwise by the measuring instrument 80A and the measuring instrument 80B. The distortion and transmission loss of the strand 23 are measured. Moreover, the measurement part 71 measures the reference | standard transmission loss which is the transmission loss before the said service with the measuring device 80B before in-service of the PC steel twisted wire 1 with an optical fiber. The measuring unit 71 causes the storage unit 73 to store the reference transmission loss measured before the use of the optical fiber-attached PC steel stranded wire 1. The measuring part 71 measures the monitoring transmission loss which is the transmission loss in the said service with the measuring device 80B during service (for example, at the time of regular inspection) of the PC steel twisted wire 1 with an optical fiber.

  The measuring unit 71 utilizes the fact that the speed of light propagating through the optical fiber strand 23 is constant, and the scattered light by the pulsed light incident on the optical fiber strand 23 is converted into a PC steel stranded wire with an optical fiber. The position in the extending direction of 1 is specified. The measuring unit 71 measures the elapsed time from when the pulsed light is incident on the optical fiber strand 23 to when the scattered light returns, thereby distortion and transmission loss of the optical fiber strand 23 corresponding to the scattered light. Is specified at which position in the extending direction of the PC steel stranded wire 1 with an optical fiber.

  The relationship acquisition unit 72 acquires the correlation between the strain of the optical fiber 23 and the transmission loss. The relationship acquisition unit 72 transmits, for example, the strain of the optical fiber 23 measured by the measuring unit 71 using the measuring instrument 80A and the transmission of the optical fiber 23 measured by the measuring unit 71 using the measuring instrument 80B. Based on the loss, the relationship of the transmission loss to the distortion is acquired. For example, the relationship acquisition unit 72 acquires the strain of the optical fiber 23 by acquiring the relationship of the transmission loss to the strain for each tension force introduced stepwise during the construction of the PC steel stranded wire with optical fiber 1. Get the correlation of transmission loss. The relationship acquisition unit 72 causes the storage unit 73 to store the acquired correlation between distortion and transmission loss.

  The storage unit 73 stores the correlation between the distortion of the optical fiber 23 and the transmission loss. Moreover, the memory | storage part 73 memorize | stores the reference | standard transmission loss measured before in-service of the PC steel twisted wire 1 with an optical fiber. The storage unit 73 has a nonvolatile storage area. The storage unit 73 is, for example, an HDD (Hard Disk Drive).

  The abnormality detection unit 74 detects an abnormality of the PC steel stranded wire with optical fiber 1 based on the correlation between strain and transmission loss. The abnormality detection unit 74 acquires a change in the strain of the optical fiber 23 based on the correlation acquired by the relationship acquisition unit 72, the reference transmission loss, and the monitoring transmission loss, and based on the acquired change in strain. To detect abnormalities in PC steel stranded wire. Specifically, the abnormality detection unit 74 acquires a reference strain that is a strain of the optical fiber 23 corresponding to the reference transmission loss, using the correlation stored in the storage unit 73. The abnormality detection unit 74 uses the correlation stored in the storage unit 73 to obtain monitoring strain that is strain of the optical fiber 23 corresponding to the monitoring transmission loss. For example, the abnormality detection unit 74 determines whether or not the change of the monitored strain with respect to the reference strain is equal to or greater than a predetermined reference value. The predetermined reference value may be a fixed value or a predetermined ratio (for example, several%) with respect to the reference strain.

  When the abnormality detection unit 74 determines that the change of the monitored strain with respect to the reference strain is equal to or greater than a predetermined reference value, the abnormality detection unit 74 detects an abnormality of the PC steel stranded wire with optical fiber 1. When the abnormality detection unit 74 detects an abnormality in the PC steel stranded wire 1 with an optical fiber, the abnormality detection unit 74 displays information on the abnormality of the PC steel stranded wire 1 with an optical fiber on the display unit 75.

  The display unit 75 visually notifies information related to the abnormality of the PC steel stranded wire with optical fiber 1 detected by the abnormality detection unit 74. The display unit 75 is a display device provided in the management device 70, for example. The display part 75 displays the information regarding abnormality of PC steel twisted wire 1 with an optical fiber as a character, an image, etc. with respect to the administrator etc. which mainly operate the management apparatus 70. FIG. The information regarding the abnormality of the PC steel stranded wire 1 with optical fiber includes information that the PC steel stranded wire 1 with optical fiber is abnormal and information that the PC steel stranded wire 1 with optical fiber is normal. It is.

  In the management apparatus 70 configured as described above, as an example, the relationship of strain with respect to the position in the extending direction of the PC steel stranded wire with optical fiber 1 is acquired by the measuring unit 71 as shown in FIG. The relationship of the transmission loss with respect to the position in the extending direction of the PC steel stranded wire with fiber 1 is acquired by the measuring unit 71 as shown in FIG. Moreover, the correlation of the distortion | strain and transmission loss matched for every tension | tensile_strength measured by the measurement part 71 is acquired by the relationship acquisition part 72 as FIG. 6 shows.

FIG. 4 is a graph illustrating strain based on Brillouin scattered light. FIG. 5 is a graph illustrating the intensity of Rayleigh scattered light. FIG. 6 is a graph illustrating the relative relationship between the strain of FIG. 4 and the strength of FIG. In FIG. 4 to FIG. 6, T ₀ through T ₇ tension of the optical fiber with PC steel twisted wire 1 in each state of the are substantially equal to each other among the FIG. More specifically, in FIG. 4 to FIG. 6, T ₆ indicates a state in which the maximum tension is introduced into the PC steel stranded wire 1 with an optical fiber, and T ₁ indicates a tension that is about half of the tension. The state in which the force is introduced into the PC steel stranded wire with optical fiber 1 is shown. T ₂ through T ₆ shows a state in which the tensioning force substantially equally dividing the tension of T ₁ and T ₆ are introduced in stages to an optical fiber with PC steel twisted wire 1. T ₇ shows a state after fixing the optical fiber with PC steel twisted wire 1 from a state of T _6. 4 to 6, T ₀ indicates a state in which no tension is introduced into the PC steel stranded wire with optical fiber 1.

In the examples of FIGS. 4 to 6, an experimental PC structure is used. The PC structure extends linearly at least from position P ₀ to position P ₁ . In this PC structure, the PC steel stranded wire with optical fiber 1 extends along the extending direction of the PC structure, and is fixed at the position P ₀ and the position P ₁ in a state where tension is introduced. . The distance from the position P ₀ to the position P ₁ is about 5 m.

The horizontal axis of FIG. 4 shows the position in the extending direction of the PC steel stranded wire 1 with optical fiber, and the vertical axis shows the amount of strain at each position of the PC steel stranded wire 1 with optical fiber. This strain is measured by the measuring unit 71 using the measuring instrument 80A. In the example of FIG. 4, at the time of construction for fixing the PC steel stranded wire with optical fiber _{1 at} the positions P ₀ and P ₁ , for example, a jack (not shown) is used for the PC steel stranded wire with optical fiber. Tension is introduced in stages. Therefore, a strain corresponding to the introduced tension is generated in the section from the position P ₀ to the position P ₁ (T _{1 to} T ₆ ). Moreover, since the PC steel stranded wire 1 with an optical fiber is fixed in the state T ₇ where the tension is relaxed from the state T ₆ where the maximum tension is introduced, the PC steel stranded wire 1 with an optical fiber is fixed. Produces a strain smaller than the tension at T ₆ (T ₇ ).

The horizontal axis of FIG. 5 shows the position in the extending direction of the PC steel stranded wire 1 with an optical fiber, and the vertical axis shows the intensity of Rayleigh scattered light at each position of the PC steel stranded wire 1 with an optical fiber. This intensity is measured by the measuring unit 71 using the measuring instrument 80B. In the example of FIG. 5, since the intensity of the Rayleigh scattered light is reduced (attenuated) in accordance with the tension introduced into the PC steel stranded wire 1 with an optical fiber, in the section from the position P ₀ to the position P ₁ . A transmission loss has occurred (T _{0 to} T ₆ ). Moreover, since the PC steel stranded wire 1 with an optical fiber is fixed in a state T ₇ where the tension is relaxed from a state T ₆ where the maximum tension is introduced, the PC with an optical fiber in the state T ₇ . steel twisted wire 1 is smaller transmission loss occurs than tension at T _6.

Based on these FIGS. 4 and 5, the amount of distortion of the position P ₀ and the position P ₁ intermediate point with optical fiber PC steel twisted wire in P _m between 1 and the intensity of Rayleigh scattered light at the intermediate point P _m Is plotted for each tension introduced into the PC steel stranded wire 1 with optical fiber, the graph of FIG. 6 is obtained. The horizontal axis of FIG. 6 shows the amount of strain of the PC steel stranded wire 1 with optical fiber, and the vertical axis shows the intensity of Rayleigh scattered light.

As shown in FIG. 6, as the tension force is gradually introduced into the PC steel stranded wire with optical fiber 1 (from the plot of T _{1 to} the plot of T ₆ ), the strain of the optical fiber strand 23 increases. A phenomenon occurs in which the amount of Rayleigh scattered light tends to decrease (decay) while the amount increases. Since the degree of attenuation of Rayleigh scattered light means the transmission loss of the optical fiber 23, there is a correlation between the distortion of the optical fiber 23 and the transmission loss of the optical fiber 23. Found to do.

In the example of FIG. 6, the tension force when the PC steel stranded wire with optical fiber 1 is fixed to the PC structure (for example, immediately before service) is T ₇ , and the intensity of Rayleigh scattered light at this time is about 42. 2 [dB]. Then, by using the correlation of FIG. 6, the intensity of Rayleigh scattered light is measured while the PC steel stranded wire with optical fiber 1 is in service, thereby grasping the decrease in tension of the PC steel stranded wire with optical fiber 1. be able to. For example, when the intensity of the measured Rayleigh scattered light increases with the passage of time during service (that is, when the transmission loss of the optical fiber strand 23 decreases), the strain of the PC steel stranded wire with optical fiber 1 increases. Since it is estimated that the quantity decreased, it can be grasped that the tension of the PC steel stranded wire with optical fiber 1 is reduced.

  A first embodiment of a management method executed using the management device 70 configured as described above will be described with reference to FIGS. 7 and 8. FIG. 7 is a flowchart illustrating processing during construction of the management method according to the first embodiment. FIG. 8 is a flowchart illustrating processing immediately before and during service of the management method according to the first embodiment. Since the degree of attenuation of Rayleigh scattered light means transmission loss as described above, for the sake of easy explanation, “Intensity of Rayleigh scattered light”, “Measurement of intensity of Rayleigh scattered light”, etc. May be simply referred to as “transmission loss”, “transmission loss measurement”, or the like.

  In the management method which concerns on this embodiment, the correlation of the distortion | strain and transmission loss of PC steel twisted wire 1 with an optical fiber is acquired at the time of construction of PC steel twisted wire 1 with an optical fiber. Then, while the PC steel stranded wire with optical fiber 1 is in service, the abnormality of the PC steel stranded wire with optical fiber 1 is detected using the acquired correlation.

  Specifically, as shown in FIG. 7, a relationship acquisition step (steps S10 to S13) is performed. First, before the tensile force is introduced into the PC steel stranded wire 1 with an optical fiber installed in the PC structure (before the tension), the strain and transmission loss of the optical fiber 23 are measured (step S10). In step S <b> 10, the measuring unit 71 measures the relationship of strain with respect to the position in the extending direction of the PC steel stranded wire with optical fiber 1 using the measuring instrument 80 </ b> A. In step S <b> 10, the measurement unit 71 measures the relationship of the transmission loss with respect to the position in the extending direction of the PC steel stranded wire with optical fiber 1 using the measuring instrument 80 </ b> B.

  Subsequently, tension is introduced into the PC steel stranded wire with optical fiber 1 installed in the PC structure (step S11). In step S11, for example, using a jack (not shown), tension is introduced stepwise into the PC steel stranded wire 1 with an optical fiber. At this time, the strain and transmission loss of the optical fiber 23 are measured for each tension introduced into the PC steel stranded wire with optical fiber 1 (step S12). In step S <b> 12, the measurement unit 71 measures the relationship of strain with respect to the position in the extending direction of the PC steel stranded wire with optical fiber 1 using the measuring instrument 80 </ b> A. In step S <b> 12, the measurement unit 71 measures the relationship of the transmission loss with respect to the position in the extending direction of the PC steel stranded wire with optical fiber 1 using the measuring instrument 80 </ b> B.

  Subsequently, the relationship acquisition unit 72 acquires the correlation between the strain of the optical fiber 23 and the transmission loss (step S13). In step S <b> 13, the relationship acquisition unit 72 acquires the correlation between strain and transmission loss associated with each tension. Finally, the PC steel stranded wire 1 with an optical fiber is fixed. Thereby, construction of the PC steel stranded wire 1 with an optical fiber is completed, and the PC steel stranded wire 1 with an optical fiber is ready for use.

  Next, immediately before (before service) and during service of the PC steel stranded wire with optical fiber 1, as shown in FIG. 8, a loss measurement step (steps S20 to S22) and an abnormality detection step (steps S23 to S23). Step S26) and a notification step (Step S27) are performed. More specifically, a loss measurement step (steps S20 and S21) is performed immediately before service (before service). During operation, the loss measurement step, the abnormality detection step, and the notification step (steps S22 to S27) are periodically performed.

  First, the reference | standard transmission loss before service of the PC steel twisted wire 1 with an optical fiber is measured (step S20). In step S20, the measuring unit 71 measures the relationship of the reference transmission loss with respect to the position in the extending direction of the PC steel stranded wire with optical fiber 1 using the measuring instrument 80B. Then, in-service of the PC steel stranded wire with optical fiber 1 is started (step S21).

  Subsequently, the monitoring transmission loss during use of the PC steel stranded wire with optical fiber 1 is measured (step S22). In step S <b> 22, the measurement unit 71 measures the relationship of the monitoring transmission loss with respect to the position in the extending direction of the PC steel stranded wire with optical fiber 1 using the measuring instrument 80 </ b> B.

  Subsequently, using the correlation acquired in step S13, the abnormality detection unit 74 acquires the reference distortion from the reference transmission loss and acquires the monitoring distortion from the monitoring transmission loss (step S23). Thereafter, the change amount of the monitored strain with respect to the reference strain is acquired (step S24).

  Subsequently, the abnormality detection unit 74 determines whether or not the amount of change in strain is greater than or equal to a predetermined reference value (step S25). When the abnormality detection unit 74 determines that the amount of change in strain is equal to or greater than a predetermined reference value (step S25: YES), it is assumed that there is an abnormality in the PC steel stranded wire with optical fiber 1, and the PC steel stranded wire with optical fiber. 1 is notified of information indicating that there is an abnormality (step S26). In step S26, information indicating that there is an abnormality in the PC steel stranded wire with optical fiber 1 is displayed on the display unit 75. In addition, you may alert | report the information that there is abnormality in the PC steel twisted wire 1 with an optical fiber to the administrator etc. of the PC steel twisted wire 1 with an optical fiber by lighting the lamp which is not shown in figure. In addition, information indicating that there is an abnormality in the PC steel stranded wire with optical fiber 1 may be notified to the administrator or the like by contacting a management room where the administrator or the like is located by a communication device (not shown). Moreover, you may alert | report the said information to the administrator etc. of the PC steel twisted wire 3 by delivering the electronic mail containing the information to the effect that the PC steel twisted wire 1 with an optical fiber has abnormality. Thereafter, a series of processing is terminated.

  On the other hand, when the abnormality detecting unit 74 determines that the amount of change in strain is not equal to or greater than a predetermined reference value (step S25: NO), it is determined that there is no abnormality in the PC steel stranded wire 1 with optical fiber, and the PC steel with optical fiber. A series of processing is completed without notifying information about abnormality of the stranded wire 1. In this case, the display unit 75 may notify information indicating that the PC steel stranded wire with optical fiber 1 is normal.

  As described above, in the management method and management device 70 according to the present embodiment, the transmission loss is measured by the measurement unit 71 in the loss measurement step. In the abnormality detection step, the abnormality detection unit 74 detects an abnormality of the PC steel stranded wire with optical fiber 1 based on the transmission loss and the correlation between the strain and the transmission loss. Thereby, in addition to the transmission loss measured by the measurement part 71, the distortion | strain of the PC steel stranded wire 1 with an optical fiber can be estimated based on a correlation. Based on the estimated strain of the PC steel stranded wire with optical fiber 1, the abnormality detecting unit 74 can detect the abnormality of the PC steel stranded wire with optical fiber 1 in the abnormality detecting step.

  In this management method and management apparatus 70, in the relationship acquisition step, the relationship acquisition unit 72 acquires the correlation between distortion and transmission loss. In the abnormality detection step, the abnormality detection unit 74 acquires strain from the transmission loss based on the correlation, and detects abnormality of the PC steel stranded wire with optical fiber 1 based on the acquired strain. Thus, the acquired correlation can be used in the abnormality detection step by acquiring the correlation between the distortion and the transmission loss in advance in the relationship acquiring step.

  In this management method and management device 70, in the relationship acquisition step, the transmission loss according to the tension introduced into the PC steel stranded wire 1 with optical fiber by the relationship acquisition unit 72 is reduced to the PC steel stranded wire 1 with optical fiber. By measuring during construction, the correlation between transmission loss and PC steel twisted wire strain is obtained. Thereby, the correlation specific to the PC structure can be acquired. In the loss measurement step, the measurement unit 71 measures the reference transmission loss and the monitoring transmission loss. In the abnormality detection step, the abnormality detection unit 74 acquires a change in strain based on the correlation, the reference transmission loss, and the monitoring transmission loss, and the abnormality in the PC steel stranded wire with optical fiber 1 based on the acquired change in strain. Is detected. Thereby, the abnormality of PC steel twisted wire 1 with an optical fiber on the basis of before service can be detected with high accuracy.

  In this management method and management device 70, in the abnormality detection step, information related to the abnormality of the PC steel stranded wire with optical fiber 1 detected by the abnormality detection unit 74 is notified by the display unit 75 in the notification step. Thereby, the information regarding the abnormality of the detected PC steel twisted wire 1 with an optical fiber can be easily recognized.

  Next, a second embodiment of the management method will be described with reference to FIG. FIG. 9 is a flowchart illustrating processing immediately before and during service of the management method according to the second embodiment. In the management method according to the present embodiment, the processing is started immediately before service of the PC steel stranded wire with optical fiber 1 (before service). The management method according to this embodiment does not acquire a correlation during construction of the PC steel stranded wire 1 with an optical fiber, while the PC steel stranded wire 1 with an optical fiber is in service. This is different from the management method according to the first embodiment in that an abnormality of the optical fiber-attached PC steel stranded wire 1 is detected using only the transmission loss.

  As shown in FIG. 9, the loss measurement step (step S30 to step S32) and the abnormality detection step (step S33 to step S35) immediately before (before service) and during service of the PC steel stranded wire 1 with optical fiber. And a notification step (step S36). More specifically, a loss measurement step (steps S30 and S31) is performed immediately before service (before service). During operation, the loss measurement step, the abnormality detection step, and the notification step (steps S32 to S36) are periodically performed.

  First, the reference | standard transmission loss before service of the PC steel twisted wire 1 with an optical fiber is measured (step S30). Thereafter, the use of the PC steel stranded wire with optical fiber 1 is started (step S31), and the monitoring transmission loss during the use of the PC steel stranded wire with optical fiber 1 is measured (step S32). These loss measurement steps (step S30 to step S32) are the same as the loss measurement steps (step S20, step S22) in the management method according to the first embodiment.

  Subsequently, the change amount of the monitored transmission loss with respect to the reference transmission loss is acquired by the abnormality detection unit 74 (step S33). Subsequently, the abnormality detection unit 74 determines whether or not the amount of change in transmission loss is equal to or greater than a predetermined reference value (step S34). When the abnormality detecting unit 74 determines that the amount of change in transmission loss is equal to or greater than a predetermined reference value (step S34: YES), it is determined that there is an abnormality in the PC steel stranded wire 1 with optical fiber, and the PC steel twist with optical fiber. Information indicating that the line 1 is abnormal is notified (step S35). This step S35 is the same as the notification step (step S35) in the management method according to the first embodiment. Thereafter, a series of processing is terminated.

  On the other hand, when the abnormality detection unit 74 determines that the change amount of the transmission loss is not equal to or greater than the predetermined reference value (step S34: NO), it is determined that there is no abnormality in the PC steel stranded wire with optical fiber 1, and the PC with optical fiber is used. A series of processes is terminated without notifying information about the abnormality of the steel stranded wire 1. In this case, the display unit 75 may notify information indicating that the PC steel stranded wire with optical fiber 1 is normal.

  Here, the principle of the phenomenon that the intensity of the Rayleigh scattered light decreases (decays) while the amount of distortion of the optical fiber 23 increases will be described with reference to FIGS. FIG. 10 is another graph illustrating strain based on Brillouin scattered light. FIG. 11 is another graph illustrating the intensity of Rayleigh scattered light. FIG. 12 is a graph illustrating the relative relationship between the strain of FIG. 10 and the strength of FIG. FIG. 13 is a graph illustrating the relationship between the strain in FIG. 10 and the difference in strength between the two points in FIG. 11.

  In the example of FIGS. 10 to 13, three PC steel stranded wires 1 with an optical fiber of about 190 m connected in series are installed in the PC structure. This PC structure extends linearly from position 0 [m] to position 600 [m] on at least the horizontal axis of FIGS. In this PC structure, the PC steel stranded wire with optical fiber 1 extends along the extending direction of the PC structure, and is fixed in a state in which a tension force is introduced. The first PC steel stranded wire with optical fiber 1 is fixed at a fixing portion provided at a pair of fixing positions at a position 30 [m] and a position 200 [m]. The second PC steel stranded wire with an optical fiber 1 is fixed at a fixing portion provided at a pair of fixing positions of a position 230 [m] and a position 400 [m]. The third PC steel stranded wire with an optical fiber 1 is fixed in a fixing portion provided at a pair of fixing positions at a position 430 [m] and a position 600 [m]. In the following description, the strain of the optical fiber strand 23 in the first PC-fiber stranded wire with an optical fiber 1 is also simply referred to as “strain of the first optical fiber strand 23”. The same applies to the second PC steel stranded wire with optical fiber 1 and the third PC steel stranded wire with optical fiber 1.

In the example of FIGS. 10 to 13, as in the examples of FIGS. 4 to 6, when the PC steel stranded wire with optical fiber 1 is installed in this PC structure, tension is introduced in stages, The strain and transmission loss of the optical fiber 23 due to force are measured. Tension of the optical fiber with PC steel twisted wire 1 in each state of the T ₁₀ through T ₁₈ in the figure, are substantially equal to each other among the figures. Specifically, T ₁₀ shows a state where tension to the optical fiber with PC steel twisted wire 1 is not introduced. T ₁₁ indicates a state in which about 5MPa of tension to the optical fiber with PC steel twisted wire 1 was introduced. T ₁₂ indicates a state in which the tension of approximately 15MPa in the optical fiber with PC steel twisted wire 1 was introduced. T ₁₃ indicates a state in which the tension of approximately 20MPa in the optical fiber with PC steel twisted wire 1 was introduced. T ₁₄ indicates a state in which the tension of approximately 25MPa in the optical fiber with PC steel twisted wire 1 was introduced. T ₁₅ indicates a state in which the tension of approximately 30MPa in the optical fiber with PC steel twisted wire 1 was introduced. T ₁₆ indicates a state in which the tension of approximately 35MPa in the optical fiber with PC steel twisted wire 1 was introduced. T ₁₇ indicates a state in which the tension force of about 40.7MPa, the largest tension to the optical fiber with PC steel twisted wire 1 was introduced. T ₁₈ shows a state after fixing the optical fiber with PC steel twisted wire 1 from a state of T _17.

  The vertical axis | shaft of FIG. 10 shows the quantity of the distortion in each position of PC steel twisted wire 1 with an optical fiber. This strain is measured by the measuring unit 71 using the measuring instrument 80A. In the example of FIG. 10, similarly to the example of FIG. 4, the strain of the optical fiber 23 is generated in the section from the position 30 [m] to the position 600 [m] according to the tension force introduced in stages. Yes.

  The vertical axis | shaft of FIG. 11 shows the intensity | strength of the Rayleigh scattered light in each position of PC steel twisted wire 1 with an optical fiber. This intensity is measured by the measuring unit 71 using the measuring instrument 80B. In the example of FIG. 11, since the intensity of the Rayleigh scattered light is reduced (attenuated) in accordance with the tension force introduced stepwise, as in the example of FIG. 5, the position 30 [m] to the position 600 [m]. ] Transmission loss has occurred in the section up to].

  Based on FIG. 10 and FIG. 11, the intensity of Rayleigh scattered light with respect to the amount of distortion of the first optical fiber strand 23 at the position 30 [m] and the second optical fiber strand 23 at the position 230 [m]. The intensity of the Rayleigh scattered light with respect to the amount of strain and the intensity of the Rayleigh scattered light with respect to the amount of strain of the third optical fiber 23 at the position 430 [m] are introduced into the PC steel stranded wire 1 with optical fiber. By plotting for each tension, the graph of FIG. 12 is obtained. The horizontal axis in FIG. 12 indicates the amount of strain of the optical fiber 23, and the vertical axis indicates the intensity of Rayleigh scattered light.

As shown in FIG. 12, in accordance with tension to the optical fiber with PC steel twisted wire 1 is introduced stepwise (from plots of T ₁₀ toward the plot of T _18), an optical fiber 23 strain The phenomenon that the intensity of Rayleigh scattered light tends to decrease (decay) while the amount increases is occurring in each of the PC steel stranded wires 1 with optical fibers. Similar to the example of FIG. 4, it is found that there is a correlation between the strain of the optical fiber 23 and the transmission loss of the optical fiber 23.

  On the other hand, based on FIG. 10 and FIG. 11, the difference in the intensity of Rayleigh scattered light (hereinafter also simply referred to as “intensity difference”) between the pair of fixing units (about 170 m) is shown as the first to third ones. The plot of FIG. 13 is obtained by plotting each of the PC steel stranded wire with optical fiber 1 for each tension introduced into the PC steel stranded wire with optical fiber 1. The horizontal axis in FIG. 13 indicates the amount of strain of the optical fiber 23, and the vertical axis indicates the intensity difference between the pair of fixing portions.

  In the example of FIG. 12, the change in the intensity of the Rayleigh scattered light with respect to the tension introduced into the PC steel stranded wire 1 with an optical fiber is shown when focusing on a predetermined position of the PC steel stranded wire 1 with an optical fiber. On the other hand, in the example of FIG. 13, the PC steel stranded wire with optical fiber 1 when the range from one fixing position to the other fixing position in the extending direction of the PC steel stranded wire with optical fiber 1 is focused. It shows the change in strength difference with the introduced tension.

  Here, when paying attention to the range from one fixing position to the other fixing position in the extending direction of the PC steel stranded wire with optical fiber 1, the following hypothesis can be considered. That is, a change in the extending direction of the PC steel stranded wire 1 with an optical fiber that affects the optical fiber 23 according to the tension introduced into the PC steel stranded wire 1 with an optical fiber (for example, with an optical fiber) This is a hypothesis that a change in the spacing of the strands 3a of the PC steel stranded wire 1 may occur, and this change may affect the light transmission in the optical fiber strand 23. Under such a hypothesis, it is considered that there is a change in intensity difference having a certain regularity in the range from one fixing position to the other fixing position in accordance with the introduced tension, and in FIG. It is considered that there is a correlation between the strain of the fiber strand 23 and the strength difference.

However, in FIG. 13, (also towards the plot of T ₁₀ for plotting T ₁₈₎ even tension to PC steel twisted wire 1 with the optical fiber is introduced stepwise, increasing or decreasing in intensity difference There is no particular trend, and no significant correlation is observed between the strain and strength difference of the optical fiber 23. Therefore, the above correlation between the distortion of the optical fiber strand 23 and the transmission loss is not the change in the extending direction of the PC steel stranded wire 1 with the optical fiber, but the optical fiber strand 23 mainly generated at the fixing position. It is thought to be due to strain.

  As described above, in the management method and management device 70 according to the present embodiment, the transmission loss is measured by the measurement unit 71 in the loss measurement step. In the abnormality detection step, the abnormality detection unit 74 detects an abnormality of the PC steel stranded wire with optical fiber 1 based on the transmission loss. Here, the measuring instrument 80B for measuring the transmission loss is simpler than the measuring instrument 80A for measuring the strain. Therefore, since the simple measuring instrument 80B which measures a transmission loss can be utilized for management of the PC steel twisted wire 1 with an optical fiber, it can detect simply the abnormality of the PC steel twisted wire 1 with an optical fiber of a PC structure. Is possible.

  By the way, as mentioned above, since the correlation between the strain of the optical fiber 23 and the transmission loss is considered to be caused by the strain of the optical fiber 23 generated at the fixing position, for example, In the fixing portion structure in which the PC steel stranded wire with optical fiber 1 is fixed to the fixing portion with a wedge, the optical fiber as described above is based on the principle that the PC steel stranded wire with optical fiber 1 is pressed by the wedge. It is expected that a phenomenon that the intensity of Rayleigh scattered light decreases (decays) while the amount of distortion of the strands 23 increases easily occurs.

  Therefore, the management method and the management device 70 described above are suitable for managing the PC steel stranded wire with an optical fiber 1 fixed on the fixing portion by the PC steel stranded wire fixing portion structure 100 as described below. .

  This PC steel stranded fixing part structure 100 is mechanically stable by pressing the fixing part 101, which is a structure such as a retaining wall provided on the rock mass R, to the rock mass R side, for example, on a dam or a slope. It is applied to the ground anchor 50 for securing the property. The plurality of PC steel stranded wires constituting the ground anchor 50 do not necessarily have to be the PC steel stranded wire 1 with an optical fiber, and even if no optical fiber is attached to some PC steel stranded wires. Good. In the following description, “PC steel stranded wire with optical fiber 1” and “part of PC steel stranded wire with no optical fiber attached” may be collectively abbreviated as “PC steel stranded wire 1, 3”. .

  FIG. 14 is a partial cross-sectional view of an example of a fixing unit structure for fixing the PC steel stranded wire with optical fiber of FIG. As shown in FIG. 14, the ground anchor 50 is provided inside the hole 103 drilled in the rock mass R and the fixing portion 101. In the ground anchor 50, the front end sides of the PC steel stranded wires 1 and 3 are inserted into the holes 103, and the rear end sides of the PC steel stranded wires 1 and 3 protrude rearward from the fixing surface 101a.

  The ground anchor 50 includes a head 51 including a PC steel stranded wire fixing portion structure 100, an anchor free length portion 52, an anchor body length portion 55, and a plurality of PC steel stranded wires. The head 51 is provided at the opening of the hole 103 in the fixing surface 101 a of the fixing unit 101. The head portion 51 fixes the rear ends of the PC steel stranded wires 1 and 3 to the fixing portion 101 by the PC steel stranded wire fixing portion structure 100. In the head 51, after a predetermined tension is applied to the PC steel stranded wires 1 and 3, the rear ends of the PC steel stranded wires 1 and 3 are fixed to the fixing portion 101 so as to maintain the tension. The

  The anchor free long portion 52 is a portion where the PC steel stranded wires 1 and 3 are not fixed in the ground anchor 50 on the front side from the fixing surface 101a. In the anchor free long part 52, the PC steel stranded wires 1 and 3 extend so as to connect the head part 51 and the anchor body long part 55. The anchor free length portion 52 includes a presser plate 53 and an array plate 54 provided in the hole 103 of the fixing portion 101. The holding plate 53 is inserted with the PC steel stranded wires 1 and 3, and seals the hole 103 between the fixed surface 101 a and the array plate 54. PC steel stranded wires 1 and 3 are inserted through the array plate 54. The array plate 54 aligns the PC steel stranded wires 1 and 3 so that the PC steel stranded wires 1 and 3 are substantially parallel to each other behind the array plate 54.

  The hole 103 in the anchor free length portion 52 is filled with the filler 5 on the front side of the presser plate 53. The hole 103 in the anchor body long part 55 is filled with the filler 5 continuously from the anchor free long part 52. The filler 5 is, for example, cement milk, mortar, or the like, and is filled in the hole 103 and cured in order to fix the PC steel stranded wires 1 and 3 in the hole 103.

  The anchor body length portion 55 is a portion for fixing the front end portions of the PC steel stranded wires 1 and 3 in the ground anchor 50. The anchor body length portion 55 has a load-bearing body 56 for fixing the front end portions of the PC steel stranded wires 1 and 3 continuously extending from the anchor free length portion 52. The load-bearing body 56 is formed by casting the front ends of the PC steel stranded wires 1 and 3 and casting, for example, an aluminum alloy.

  The PC steel stranded wire fixing unit structure 100 is disposed behind the base unit 11 and a base unit 11 which is in contact with the fixing surface 101a of the fixed unit 101 and through which the PC steel stranded wires 1 and 3 are inserted. The socket part 13 which penetrates the steel twisted wires 1 and 3 and the wedge part 16 arrange | positioned between the inner wall surface 13s of the taper hole 13a of the socket part 13 and the PC steel twisted wires 1 and 3 are provided.

  The base portion 11 is a bearing plate that supports the tension of the PC steel stranded wires 1 and 3. The base part 11 has a circular opening 11a through which a plurality of PC steel stranded wires 1 and 3 are inserted. The base portion 11 is formed with a plurality of screw holes for attaching a cap member 14 to be described later. Between the base part 11 and the socket part 13, a columnar spacer member 12 having a through hole through which the PC steel stranded wires 1 and 3 are inserted is inserted. The diameter of the front surface of the spacer member 12 is larger than the diameter of the circular opening 11a. The socket portion 13 is a columnar member disposed on the rear surface of the spacer member 12. As an example, the diameter of the front surface of the socket portion 13 is smaller than the diameter of the rear surface of the spacer member 12.

  The spacer member 12 and the socket part 13 are covered with a cap member 14. The cap member 14 has a hat shape, and is fixed by screwing a bolt B into a screw hole of the base portion 11. An O-ring 14 c is disposed between the cap member 14 and the base portion 11, and a sealed space is defined by the cap member 14 and the base portion 11. This sealed space includes a space behind the presser plate 53 in the hole 103. This sealed space is filled with rust preventive oil 15. The rust preventive oil 15 is injected through the injection port 14a. At the top of the cap member 14, an exhaust port 14 b for discharging the air in the sealed space is provided.

  FIG. 15 is an exploded perspective view of the socket portion and the wedge portion of the fixing portion structure shown in FIG. As shown in FIG. 15, the socket portion 13 is formed with a taper hole 13 a through which a plurality of (here, four) PC steel stranded wires 1 and 3 are inserted. The tapered hole 13a has a conical surface formed such that its inner wall surface 13s decreases in diameter toward the front.

  The wedge portion 16 functions as a wedge in a state where it is inserted from the rear between the inner wall surface 13s of the tapered hole 13a and the PC steel stranded wires 1 and 3 (hereinafter also simply referred to as “inserted state”). The wedge portion 16 has a truncated cone (tapered) wedge body 17 having a through hole in the center. The outer wall surface of the wedge body 17 is a conical surface corresponding to the inner wall surface 13s of the tapered hole 13a. The inner wall surface 17 d of the wedge body 17 is a cylindrical surface corresponding to the outer peripheral surface of the PC steel stranded wires 1 and 3, and is in close contact with the outer peripheral surface of the PC steel stranded wires 1 and 3. As an example, the wedge body 17 includes three wedge pieces 17a, 17b, and 17c that are formed by being divided into three in the circumferential direction.

  The wedge pieces 17a to 17c are arranged at equal intervals so as to surround the PC steel stranded wires 1 and 3 in the circumferential direction in the inserted state. The front end surfaces 17t of the wedge pieces 17a to 17c are substantially flush with the front surface of the socket portion 13. The rear ends of the wedge pieces 17 a to 17 c protrude rearward from the rear surface of the socket portion 13. The rear end portions of the PC steel stranded wires 1 and 3 protrude further rearward from the rear end surfaces 17u of the wedge pieces 17a to 17c.

  The wedge body 17 is inserted from the rear between the inner wall surface 13 s of the tapered hole 13 a of the socket portion 13 and the PC steel stranded wires 1 and 3 inserted through the socket portion 13. The wedge body 17 functions as a wedge between the socket portion 13 and the PC steel stranded wires 1 and 3. Specifically, in the inserted state, the wedge bodies 17 respectively press the inner wall surface 13s of the tapered hole 13a of the socket portion 13 and the PC steel stranded wires 1 and 3 inserted through the socket portion 13. When a predetermined tension is applied to the PC steel stranded wires 1 and 3, the wedge body 17 presses the PC steel stranded wires 1 and 3 more strongly, so that the PC steel stranded wires 1 and 3 are firmly held. Thus, the PC steel stranded wires 1 and 3 are fixed to the fixing portion 101 so as to support the tension. At this time, the wedge body 17 strongly presses the PC steel stranded wires 1 and 3 in the radial direction by the inner wall surface 17 d of the wedge body 17.

  As described above, the management device 70 is in contact with the fixed portion 101 and through which the PC steel stranded wire with optical fiber 1 is inserted, and the PC steel with optical fiber installed behind the base portion 11. PC steel twisted wire fixing portion comprising a socket portion 13 through which the stranded wire 1 is inserted, and a wedge portion 16 inserted from the rear between the inner wall surface 13s of the socket portion 13 and the PC steel stranded wire 1 with an optical fiber. The structure 100 can be preferably applied to the PC steel stranded wire 1 with an optical fiber fixed to the fixing portion 101. Thereby, the abnormality of the PC steel twisted wire 1 with an optical fiber of a PC structure is simply detected using the transmission loss generated by the PC steel twisted wire 1 with an optical fiber being pressed by the inserted wedge portion 16. It becomes possible.

  As mentioned above, although embodiment of this invention was described, this invention is not restricted to the said embodiment, You may change in the range which does not change the summary described in each claim.

  For example, the present invention is not limited to the case where the present invention is applied to the PC steel stranded wire 3 having the seven PC steel strands 4 as in the above embodiment. For example, the 19 stranded PC steel stranded wire or other PC The same applies to steel stranded wires. Moreover, although the two optical fiber members 20 were attached to PC steel twisted wire 1 with an optical fiber, the number of the optical fiber members 20 is not limited to this.

  In the said embodiment, although the ground anchor 50 was illustrated as PC structure, the structure using the prestressed concrete etc. may be sufficient as PC structure. Moreover, the tension | tensile_strength of the PC steel twisted wire 1 with an optical fiber may be introduce | transduced by the post tension system, and may be introduced by the pre tension system.

  In the said embodiment, although the abnormality detection part 74 used the transmission loss before service of the PC steel twisted wire 1 with an optical fiber as a reference | standard, in order to detect the abnormality of the PC steel twisted wire 1 with an optical fiber, to this, It is not limited. Specifically, although the loss measurement step includes step S20 in FIG. 8 and step S30 in FIG. 9, these steps may not be included. In this case, in FIG. 8, the abnormality of the PC steel stranded wire with optical fiber 1 may be detected using a strain value (for example, a fixed value) obtained in advance by design or simulation as a reference strain. Moreover, in FIG. 9, you may detect the abnormality of PC steel twisted wire 1 with an optical fiber, using the transmission loss value (for example, fixed value) calculated | required by design or simulation beforehand as a reference transmission loss.

  In the said embodiment, although the correlation was previously acquired by the relationship acquisition part 72 during construction of the PC steel twisted wire 1 with an optical fiber, it is not limited to this. The correlation may be acquired by, for example, simulation or the like separately from the construction of the PC steel stranded wire 1 with an optical fiber.

  In the said embodiment, although the display part 75 which alert | reports the information regarding the abnormality of PC steel twisted wire 1 with an optical fiber was used as an alerting | reporting part, the information regarding the abnormality of PC steel twisted wire 1 with an optical fiber was audibly heard. A buzzer, a speaker, or the like for informing the user may be used, or a buzzer, a speaker, or the like for audibly informing information related to the abnormality of the PC steel stranded wire with optical fiber 1 may be used.

  In the above embodiment, the four taper holes 13a are formed in the socket part 13, but the number of the taper holes 13a is not limited to this. Further, the wedge body 17 is divided into three wedge pieces by being divided into three in the circumferential direction. However, the number of wedge bodies divided (the number of wedge pieces constituting one wedge body) is not limited to this.

  DESCRIPTION OF SYMBOLS 1 ... PC steel twisted wire with optical fiber, 3 ... PC steel twisted wire, 3a ... Twist, 11 ... Base part, 13 ... Socket part, 16 ... Wedge part, 20 ... Optical fiber member (optical fiber), 23 ... Light Fiber strand (optical fiber), 70 ... management device, 71 ... measuring section, 74 ... abnormality detecting section, 75 ... display section (notification section), 100 ... fixing section structure, 101 ... fixing section.

Claims (9)

Management for managing a PC steel stranded wire with an optical fiber, including a PC steel stranded wire formed by twisting a plurality of PC steel strands, and an optical fiber installed along a twist line of the PC steel stranded wire A method,
A loss measurement step of measuring a transmission loss of scattered light of the light incident on the optical fiber;
An abnormality detection step of detecting an abnormality of the PC steel stranded wire based on the transmission loss measured in the loss measurement step.   The management method according to claim 1, wherein in the abnormality detection step, an abnormality of the PC steel stranded wire is further detected based on a correlation between the transmission loss and the strain of the PC steel stranded wire. A relationship acquisition step of acquiring the correlation;
The management according to claim 2, wherein in the abnormality detection step, strain is acquired from the transmission loss based on the correlation acquired in the relationship acquisition step, and abnormality of the PC steel stranded wire is detected based on the acquired strain. Method. In the relation acquisition step, the transmission loss and the strain of the PC steel stranded wire are measured by measuring the transmission loss according to the tension force introduced into the PC steel stranded wire during the construction of the PC steel stranded wire with optical fiber. The correlation with
In the loss measurement step, a reference transmission loss that is a transmission loss before the use of the PC steel stranded wire with an optical fiber and a monitoring transmission loss that is a transmission loss during the use of the PC steel stranded wire with an optical fiber are measured. And
In the abnormality detection step, a strain change is obtained based on the correlation obtained in the relationship obtaining step, the reference transmission loss, and the monitoring transmission loss, and the PC steel is obtained based on the obtained strain change. The management method of Claim 3 which detects abnormality of a twisted wire.   The management method as described in any one of Claims 1-4 further equipped with the alerting | reporting step which alert | reports the information regarding the abnormality of the said PC steel twisted wire detected by the said abnormality detection step. Management for managing a PC steel stranded wire with an optical fiber, including a PC steel stranded wire formed by twisting a plurality of PC steel strands, and an optical fiber installed along a twist line of the PC steel stranded wire A device,
A measurement unit for measuring a transmission loss of scattered light of light incident on the optical fiber;
A management apparatus comprising: an abnormality detection unit that detects an abnormality of the PC steel stranded wire based on the transmission loss measured by the measurement unit.   The management apparatus according to claim 6, wherein the abnormality detection unit detects an abnormality of the PC steel stranded wire based further on a correlation between the transmission loss and the strain of the PC steel stranded wire.   The management apparatus of Claim 6 or 7 further provided with the alerting | reporting part which alert | reports the information regarding the abnormality of the said PC steel twisted wire detected by the said abnormality detection part.   The PC steel stranded wire with optical fiber is in contact with the portion to be fixed and the base portion through which the PC steel stranded wire with optical fiber is inserted, and is installed at a position opposite to the portion to be fixed when viewed from the base portion. A socket part through which the PC steel stranded wire with optical fiber is inserted, and a wedge part inserted between the inner wall surface of the socket part and the PC steel stranded wire with optical fiber from the side opposite to the base part The management device according to any one of claims 6 to 8, wherein the fixing device is fixed to the fixed portion by a fixing portion structure.

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