JP6474345B2 - PC steel twisted wire fixing part structure, ground anchor, measuring device and measuring method - Google Patents

Description

  The present invention relates to a fixing structure of a PC steel stranded wire, a ground anchor, a measuring device, and a measuring method.

  Conventionally, the tension of the PC steel stranded wire by the PC steel stranded wire with an optical fiber in which the optical fiber is attached to the PC steel stranded wire used for tensile materials and tension materials of various structures (bridges, buildings, slopes, etc.) Is being measured. As a technique related to such a PC steel stranded wire with an optical fiber, for example, a tension member described in Patent Document 1 is known. The tension member includes a hollow body, an optical fiber housed inside the hollow body, and a plurality of tension strands that are twisted so as to surround the outer periphery of the hollow body and bear a tension force.

Japanese Patent No. 5604760

  The PC steel stranded wire is fixed to a load-bearing body or the like, for example, by a crimping portion that is crimped and attached to an end portion of the PC steel stranded wire. By fixing the load-bearing body or the like on the fixing portion, the PC steel stranded wire transmits a tension force or the like via the crimping portion. Therefore, it is desirable to fix the PC steel stranded wire with an optical fiber so that the tension of the PC steel stranded wire can be measured up to the position of the crimping portion.

  By the way, when attaching an optical fiber part to a PC steel twisted wire formed by twisting a plurality of PC steel strands and having a helical twist, the optical fiber may be installed at the twist. In this case, in order to measure the tension of the PC steel stranded wire up to the position of the crimping portion, the optical fiber portion is passed between the inner wall surface of the crimping portion and the PC steel stranded wire. However, in the fixing part structure of the PC steel stranded wire using the crimping part, usually, the PC steel stranded wire crimped by the crimping part around the front end is strongly pressed in the radial direction, and the PC steel stranded wire has the crimping part. In close contact. Therefore, it is difficult to pass the optical fiber portion between the inner wall surface of the crimping portion and the PC steel stranded wire. As a result, it is difficult to measure the tension of the PC steel stranded wire up to the position of the crimping part.

  Then, an object of this invention is to provide the fixing | fixed part structure of PC steel twisted wire, a ground anchor, a measuring apparatus, and a measuring method which can measure the tension | tensile_strength of PC steel twisted wire to the position of a crimping | compression-bonding part.

  The fixing structure of the PC steel stranded wire according to the present invention is a PC steel stranded wire formed by twisting a plurality of PC steel strands and having a helical knitting, an optical fiber portion installed at the knitting, A fixing portion structure of a PC steel stranded wire with an optical fiber that fixes a PC steel stranded wire with an optical fiber to a fixing portion, and is provided inside a fixing hole cut in the fixing portion. A load-bearing body for fixing a PC steel stranded wire with an optical fiber to a fixing hole through a filler filled inside, and a PC steel stranded wire with an optical fiber provided in the load-bearing body and fixed by the load-bearing body as a load-bearing body A fixing portion for fixing, and the fixing portion includes a crimping portion that is crimped around the PC steel stranded wire with optical fiber at the front end portion of the PC steel stranded wire with optical fiber, and the optical fiber portion has a twisted line. Placed between the optical fiber strand placed on the inner wall surface of the crimping part and the PC steel stranded wire. Has a protective tube for accommodating the optical fiber, the.

  In this PC steel stranded wire fixing part structure, the PC steel stranded wire with optical fiber is fixed to the load bearing body by being crimped by a crimping part at the front end thereof, and fixed to the fixing hole via a filler. The In this structure, since the front end portion of the PC steel stranded wire is crimped together with the crimping portion, it is strongly pressed in the radial direction by the inner wall surface of the crimping portion, and the outer peripheral surface of the PC steel stranded wire and the crimping portion are in close contact with each other. . Here, since the optical fiber is accommodated in the protective tube, the optical fiber can be protected from the pressing force applied from the inner wall surface of the crimping portion by being strongly pressed in the radial direction by the inner wall surface of the crimping portion. it can. Therefore, the optical fiber portion of the PC steel stranded wire with optical fiber is installed at the strand of the PC steel stranded wire in a state where the optical fiber strand is accommodated in the protective tube, and the inner wall surface of the crimping portion and the PC steel stranded wire Can be placed between. Therefore, the optical fiber portion can be passed between the inner wall surface of the crimping portion and the PC steel stranded wire, and the tension of the PC steel stranded wire can be measured up to the position of the crimping portion.

  Further, in the PC steel stranded wire fixing part structure, the protective tube preferably has a yield strength higher than the yield strength of the crimping part. In this case, the optical fiber can be more reliably protected from the pressing force from the inner wall surface of the crimping portion.

  Further, in the fixing structure of the PC steel stranded wire, the PC steel stranded wire with optical fiber has at least a pair of optical fiber strands, and the pair of optical fiber strands is a front end portion of the PC steel stranded wire with optical fiber. May be connected to each other. In this case, for example, when measuring the strain of one PC fiber stranded wire with an optical fiber using a measuring device, information on the reciprocal strain can be acquired. Moreover, the connection operation | work which connects a pair of optical fiber strands mutually can be easily performed in the front-end part of PC steel twisted wire with an optical fiber.

  The present invention can also be understood as an invention of a ground anchor having the above-mentioned PC steel stranded wire fixing portion structure.

  In this ground anchor, for example, when measuring the strain of an optical fiber for a PC steel stranded wire with an optical fiber using a measuring device, information on the reciprocal strain can be acquired. The distortion of the PC steel stranded wire with an optical fiber in the provided ground anchor can be suitably measured.

  The present invention can also be understood as an invention of a measuring device, which is a measuring device for measuring the strain of a PC steel stranded wire with an optical fiber in the fixing structure of the PC steel stranded wire. The optical signal transmitting unit for transmitting an optical signal to one rear end of the optical fiber strands connected to each other at the front end, and the other rear end of the optical fiber strand connected to each other at the front end An optical signal receiving unit that receives an optical signal, and an analysis unit that analyzes the optical signal received by the optical signal receiving unit and acquires information related to distortion of the PC steel stranded wire with optical fiber.

  In this measuring device, an optical signal is transmitted to one rear end of the optical fiber by the optical signal transmitter, and an optical signal is received from the other rear end of the optical fiber by the optical signal receiver. can do. Therefore, a pair of optical signal transmitters and optical signal receivers is sufficient for two optical fiber strands, so the number of optical signal transmitters and optical signal receivers can be reduced with respect to the number of optical fiber strands. it can.

  Moreover, this invention can also be grasped | ascertained also as invention of a measuring method, and the measuring method prepares the ground anchor which has the fixing | fixed part structure of said PC steel twisted wire, and the preparatory process which installs multiple ground anchors on a slope And an optical signal transmitter that transmits an optical signal is connected to one rear end of optical fiber wires connected to each other at the front end, and an optical signal receiver that receives an optical signal is connected to each other at the front end. The connection process for connecting to the other rear end of the connected optical fiber, and the optical signal received by the optical signal receiving unit are analyzed by the analyzing unit to obtain information on the distortion of the PC steel stranded wire with optical fiber. And a measuring step for measuring the underground strain on the slope.

  In this measurement method, since the ground anchor installed in the installation process can acquire information related to the reciprocal distortion, the optical signal transmission unit is connected to one rear end of the optical fiber to connect the optical fiber. By connecting the signal receiving unit to the other rear end of the optical fiber, the underground strain on the slope can be easily measured.

  ADVANTAGE OF THE INVENTION According to this invention, the fixing | fixed part structure, ground anchor, measuring apparatus, and measuring method of PC steel twisted wire which can measure the tension | tensile_strength of PC steel twisted wire to the position of a crimping | compression-bonding part can be provided.

FIG. 1 is a diagram showing an overall configuration of a ground anchor to which a PC steel stranded wire fixing portion structure according to an embodiment of the present invention is applied. Fig.2 (a) is a perspective view of PC steel twisted wire with an optical fiber. FIG. 2B is a perspective view showing an example of the protective tube. FIG. 3 is a partial cross-sectional view showing a PC steel stranded wire with an optical fiber and a crimping portion. FIG. 4 is a partial cross-sectional view showing the anchor body length in FIG. Fig.5 (a) is sectional drawing along the center axis line of a crimping | compression-bonding part. FIG. 5B is a partial cross-sectional view along the central axis of the insertion portion and a plan view of the insertion portion. FIG. 6 is a block diagram illustrating an example of a measurement apparatus.

  Hereinafter, embodiments of a PC steel twisted wire fixing portion structure, a ground anchor, a measuring device, and a measuring method 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 words having concepts such as “front”, “rear”, “front end”, “rear end”, etc. are used, the upper side in FIG. 1 and FIG. The lower part is the front.

  FIG. 1 is a diagram illustrating an overall configuration of a ground anchor having a fixing structure of a PC steel stranded wire according to an embodiment of the present invention. Fig.2 (a) is a perspective view of PC steel twisted wire with an optical fiber. FIG. 2B is a perspective view showing an example of the protective tube. The PC steel stranded wire fixing part structure 100 according to the present embodiment presses a structure 101 such as a retaining wall provided on a rock mass (fixed part) R to the rock mass R side, for example, on a dam or a slope. It is applied to the ground anchor 50 for ensuring the mechanical stability. 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 the optical fiber portion is not disposed on some PC steel stranded wires. Also good. In the following description, “PC steel stranded wire with optical fiber 1” and “part of PC steel stranded wire in which the optical fiber portion is not disposed” may be collectively abbreviated as “PC steel stranded wire 1, 3”. is there.

  As shown in FIG. 1, the ground anchor 50 is provided inside a fixing hole 103 drilled in the rock mass R and the structure 101. The fixing hole 103 is drilled in the rock mass R and the structure 101 with a diameter of 90 to 165 mm, for example. In the ground anchor 50, the front end side of the PC steel stranded wires 1 and 3 is inserted into the fixing hole 103 with a length of about 20 to 100 m, for example, and the rear end side of the PC steel stranded wires 1 and 3 is about 150 to 350 mm, for example. It protrudes backward from the surface 101a in length.

  The ground anchor 50 includes a head 51 including a PC steel stranded wire fixing part structure 100, an anchor free length 52, an anchor body length 55, and a plurality of PC steel stranded wires 1 and 3. The head 51 is provided at the opening of the fixing hole 103 on the surface 101 a of the structure 101. 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 structure 101 so as to maintain the tension. .

  The anchor free length 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 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 long portion 52 includes a presser plate 53 and an array plate 54 provided in the fixing hole 103 of the structure 101. The holding plate 53 is inserted with the PC steel stranded wires 1 and 3, and seals the fixing hole 103 between the 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 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 long portion 55 fixes the front end portions of the PC steel stranded wires 1 and 3 to the fixing hole 103 of the rock mass R by the fixing portion structure 100 of the PC steel stranded wire. Specifically, 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 fixes the PC steel stranded wires 1 and 3 to the fixing hole 103 through the filler 5 described later.

  In the anchor body long part 55, as an example, a plurality of load bearing bodies 56 are provided in series inside the fixing hole 103. The load-bearing bodies 56 are arranged at a predetermined pitch (for example, every 1.5 m) along the PC steel stranded wires 1 and 3. The number of load-bearing bodies 56 is, for example, the number obtained by dividing the number of installed PC steel stranded wires 1 and 3 by two. The number of installed PC steel stranded wires 1 and 3 is not particularly limited, but may be an even number (4 in this case).

The load-bearing body 56 includes a load-bearing body main body 57 in which the front ends of the PC steel stranded wires 1 and 3 are disposed, a reinforcing bar 58 provided so as to surround the PC steel stranded wires 1 and 3 behind the load-bearing body main body 57, and Have
The load-bearing body main body 57 is a columnar member formed by casting aluminum alloy or the like, for example. The load-bearing body 57 includes a fixing portion 60 for fixing the PC steel stranded wires 1 and 3 fixed by the load-bearing body 57 to the load-bearing body 57 and a PC steel stranded wire not fixed by the load-bearing body 57. A through hole 57a (see FIG. 1) through which 1 and 3 can be inserted is provided. The load-bearing body 57 is provided with, for example, two fixing portions 60, and is provided with a number of through holes 57 a that are two less than the number of PC steel stranded wires 1 and 3 installed. Details of the fixing unit 60 will be described later.

  In the load-bearing body main body 57 other than the foremost end of the anchor body long portion 55, the PC steel stranded wires 1 and 3 fixed by the load-bearing body main body 57 are fixed to the fixing portion 60, and on the front side of the load-bearing body main body 57. PC steel stranded wires 1 and 3 to be extended are inserted into the through holes. In the load bearing body main body 57 at the foremost end of the anchor body long portion 55, the PC steel stranded wires 1 and 3 fixed by the load bearing body main body 57 are fixed to the fixing portion 60.

  The reinforcing bars 58 are metal spring-like members provided behind the respective load-bearing body main bodies 57. The reinforcing bars 58 extend three-dimensionally in the filler 5 behind each load-bearing body main body 57, and reinforce the strength of the surrounding filler 5. The front end of the reinforcing bar 58 is disposed on the stepped portion 57f (see FIG. 4) of the load-bearing body main body 57.

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

  As shown in FIG. 2, the PC steel stranded wire 1 with an optical fiber includes a PC steel stranded wire 3 and an optical fiber portion 20 disposed on the surface of the PC steel stranded wire 3. The PC steel stranded wire with optical fiber 1 preferably has at least a pair of optical fiber portions 20. The PC steel stranded wire 3 is a stranded wire formed by twisting a plurality (19 in this embodiment) of PC steel strands 4a to 4c made of, for example, a strand steel material. The PC steel strand 4 a is a strand disposed on the outermost periphery of the PC steel stranded wire 3. The PC steel strand 4b is a strand arranged inside the PC steel strand 4a. The PC steel strand 4 c is a strand disposed inside the PC steel strand 4 b and disposed at the center of the PC steel stranded wire 3.

  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 the two adjacent PC steel strands 4a, 4a. The valley is inclined at a predetermined angle on the surface of the PC steel stranded wire 3 with respect to the bus extending parallel to the central axis A of the PC steel stranded wire 3 and extends in a spiral shape with the central axis A as the center. To do. In other words, the PC steel stranded wire 3 has a helical twist 3a. A sheath 2 is provided on the surface of the PC steel stranded wire 3 as a coating for preventing corrosion.

  The optical fiber portions 20 are respectively installed on two of the twist lines 3a and extend in a spiral shape. Each of the pair of optical fiber portions 20 includes an optical fiber main body 21 and a protective tube 25 that accommodates the optical fiber main body 21. The optical fiber main body 21 has an optical fiber strand 23 that transmits an optical signal and a coating 24 that covers the optical fiber strand 23. The coating 24 is made of, for example, a polyamide-based material. The protective tube 25 accommodates the optical fiber main body 21 and protects the accommodated optical fiber main body 21 from the pressing force applied from the inner wall surface of the crimping portion 30.

  The protective tubes 25 are respectively installed on two of the folds 3a and extend spirally. The protective tube 25 is installed so as to be embedded in the valley and extends spirally along the adjacent PC steel wires 4a, 4a between the adjacent PC steel wires 4a, 4a. Is installed. Therefore, the optical fiber main body 21 (optical fiber strand 23) accommodated in the protective tube 25 extends spirally along the fold 3a.

  Protective tube 25 includes PC steel constituting PC steel stranded wires 1 and 3 and the surfaces of adjacent PC steel strands 4a and 4a in the cross section perpendicular to the central axis direction of PC steel stranded wires 1 and 3, respectively. It is accommodated in a region surrounded by a common circumscribed circle of the strands 4a to 4c (see FIG. 3). That is, the optical fiber portion 20 is installed on the strand 3a of the PC steel stranded wire 3 in a state where the optical fiber strand 23 is accommodated in the protective tube 25, and the inner wall surface of the crimping portion 30 (the insertion portion 32 described later). 32d) and the PC steel stranded wire 3. The protective tube 25 has a yield strength higher than the yield strength of the crimping portion 30 (a main body portion 31 and an insertion portion 32 described later) before being crimped. As a material of the protective tube 25, for example, a material such as titanium nitride, high-speed tool steel, or alloy tool steel is preferable.

  FIG. 4 is a partial cross-sectional view showing the anchor body length in FIG. Fig.5 (a) is sectional drawing along the center axis line of a crimping | compression-bonding part. FIG. 5B is a partial cross-sectional view along the central axis of the insertion portion and a plan view of the insertion portion.

  As shown in FIG. 4, in the PC steel stranded wire fixing unit structure 100, the PC steel stranded wires 1 and 3 are fixed to the load bearing body main body 57 by a fixing portion 60 provided on the load bearing body main body 57. The fixing portion 60 includes two locking portions 57b provided on the load-bearing body main body 57, and a crimping portion 30 that is locked to the locking portion 57b in a state of being crimped together with the PC steel stranded wires 1 and 3. . The locking part 57b is a cylindrical hole having an inner diameter larger than the outer diameter of the crimping part 30 after crimping. A through hole 57g having an inner diameter larger than the outer diameter of the PC steel stranded wire with optical fiber 1 and smaller than the inner diameter of the locking portion 57b is formed coaxially with the locking portion 57b on the rear side of the locking portion 57b. Yes. PC steel stranded wires 1 and 3 are inserted into the through hole 57g from the rear side, and a crimping portion 30 surrounding the front end portion of the PC steel stranded wires 1 and 3 is attached to the front side of the through hole 57g. Therefore, the PC steel stranded wires 1 and 3 are prevented from coming out from the through hole 57g to the rear side. With such a structure, since the crimping portion 30 is locked to the locking portion 57b, the PC steel stranded wires 1, 3 crimped together with the crimping portion 30 are fixed to the load-bearing body main body 57, and the PC steel stranded wire 1, 3 tension force is supported by the load-bearing body 57.

  As shown in FIG. 5, the crimping portion 30 includes a cylindrical main body portion 31 and a cylindrical insertion portion 32 that overlaps the inner wall surface 31 d of the main body portion 31. In the example of FIG. 5, the crimping portion 30 in a state before being crimped is shown. The main body 31 is a cylindrical member made of, for example, SCM435. In the state where the main body 31 is locked to the locking portion 57b, the outer wall surface 31a of the main body 31 faces the inner wall surface of the locking portion 57b, and the rear end portion 31b of the main body 31 is the locking portion. It contacts the rear surface 57h of 57b. On the inner wall surface 31d of the main body 31, a groove 31e extending in the circumferential direction is formed on the rear end 31b side.

  The insertion part 32 is a cylindrical member whose material is SCM415, for example. The insertion part 32 has a shorter overall length in the central axis direction than the main body part 31. In a state where the main body portion 31 is locked to the locking portion 57b, the outer wall surface 32a of the insertion portion 32 abuts the front of the inner wall surface 31d of the main body portion 31, and the rear end portion 32b of the insertion portion 32 is the main body. The front end portion 32 c of the insertion portion 32 is positioned substantially flush with the front end portion 31 c of the main body portion 31. The inner wall surface 32d of the insertion portion 32 is brought into close contact with the outermost PC steel strand 4a of the PC steel stranded wires 1 and 3 by pressure bonding. The insertion portion 32 is provided with a pair of cutout portions 32e extending along the central axis from the rear end portion 32b toward the front. A region where the insertion portion 32 is not disposed is present on the rear side of the inner wall surface 31 d of the main body portion 31. This region is brought into close contact with the outer peripheral surface of the sheath 2 of the PC steel stranded wires 1 and 3 by crimping (see FIG. 4).

  In such a fixing portion 60, the front end portion 1a is crimped together with the crimping portion 30 inserted into the front end portion 1a of the PC steel stranded wires 1, 3, so that the PC steel stranded wires 1, 3 are connected to the load-bearing body main body 57. Fixed to. Thereby, the PC steel stranded wires 1 and 3 are fixed to the fixing hole 103 through the filler 5. In this structure, when the crimping portion 30 is crimped, the PC steel stranded wires 1 and 3 are strongly pressed in the radial direction by the inner wall surface of the crimping portion 30 (the inner wall surface 31d of the main body 31 and the inner wall surface 32d of the insertion portion 32). Then, the inner wall surface of the crimping portion 30 and the outer peripheral surface of the front end portion 1a of the PC steel stranded wires 1 and 3 are in close contact with each other.

  Here, since the protective tube 25 is installed in the twist line 3a of the PC steel stranded wire 3, the inner wall surface of the crimping portion 30 and the outer peripheral surface of the front end portion 1a of the PC steel stranded wire 1, 3 are brought into close contact by crimping. Even if it does, it will be avoided that the internal space of the protective tube 25 is crushed by the protective tube 25. In this way, a path through which the optical fiber main body 21 is passed between the inner wall surface of the crimping portion 30 and the PC steel stranded wires 1 and 3 is secured, and the optical fiber main body from the pressing force applied from the inner wall surface of the crimping portion 30. 21 is protected. As a result, the tension of the optical fiber-attached PC steel stranded wire 1 can be measured up to the position of the crimping portion 30.

  A cap 57 c that seals the front end portion is attached to the load-bearing body main body 57. The cap 57c is attached to the load bearing body 57 by screwing the cap fixing bolt 57d into the fixing bolt hole 57e. The cap 57c is provided with a through hole into which the pair of bolts B are screwed, and rust preventive oil or the like is injected into the space 57v in front of the locking portion 57b through the through hole. In the space 57v, the optical fiber strands 23 of the pair of optical fiber portions 20 are connected to each other at the front end portion 1a of the PC steel stranded wire 1 with an optical fiber.

  As described above, in the PC steel stranded wire fixing portion structure 100 according to the present embodiment, the PC steel stranded wire with optical fiber 1 is crimped around the front end portion 1a by the crimping portion 30 so as to have a load bearing body. It is fixed to the main body 57 and fixed to the fixing hole 103 via the filler 5. In this structure, since the front end 1a of the PC steel stranded wire with optical fiber 1 is crimped together with the crimping portion 30, it is strongly pressed in the radial direction by the inner wall surface of the crimping portion 30, and the front end of the PC steel stranded wire with optical fiber 1 The outer peripheral surface of the portion 1a and the crimping portion 30 are in close contact. Here, since the optical fiber main body 21 is accommodated in the protective tube 25, the optical fiber main body 21 is protected from the pressing force applied from the inner wall surface of the crimping portion 30 by being strongly compressed in the radial direction by the inner wall surface of the crimping portion 30. can do. Therefore, the optical fiber portion 20 of the PC steel stranded wire with optical fiber 1 is installed in the stranded portion 3a of the PC steel stranded wire 3 in a state where the optical fiber main body 21 is accommodated in the protective tube 25. It can arrange | position between a wall surface and the PC steel twisted wire 3. FIG. Therefore, the optical fiber portion 20 can be passed between the inner wall surface of the crimping portion 30 and the PC steel stranded wire 3, and the tension of the PC steel stranded wire with optical fiber 1 can be measured up to the position of the crimping portion 30. It becomes possible.

  Further, in the PC steel stranded wire fixing part structure 100, the protective tube 25 has a yield strength higher than the yield strength of the crimping part 30 before being crimped. Thereby, the optical fiber main body 21 can be more reliably protected from the pressing force from the inner wall surface of the crimping part 30.

  Moreover, in the fixing part structure 100 of the PC steel stranded wire, the PC steel stranded wire with optical fiber 1 has at least a pair of optical fiber strands 23, and the pair of optical fiber strands 23 is a PC steel stranded wire with optical fiber. The front ends 1a of the lines 1 are connected to each other. Thereby, for example, when measuring the strain of one optical steel-attached PC steel stranded wire 1 using a measuring device 70 described later, it is possible to acquire information on the reciprocal strain. Moreover, the connection operation | work which connects a pair of optical fiber strand 23 mutually can be easily performed in the front-end part 1a of the PC steel twisted wire 1 with an optical fiber.

  In the ground anchor 50 according to the present embodiment, for example, when measuring the strain of the optical fiber 23 with respect to one PC steel twisted wire 1 with an optical fiber using a measuring device 70 described later, information on the reciprocal strain is provided. Since it can be acquired, the strain at the ground anchor 50 provided in the fixing hole 103 can be suitably measured.

  In addition, in the conventional PC steel stranded wire fixing part structure, when trying to avoid compression of the optical fiber part by the crimping part, do not pass the optical fiber part between the inner wall surface of the crimping part and the PC steel stranded wire. In addition, it is necessary to pull out the optical fiber portion from the PC steel stranded wire with optical fiber and fix the PC steel stranded wire with optical fiber on the front side of the crimping portion. If it does so, the tension | tensile_strength of PC steel twisted wire cannot be measured to the position of a crimping | compression-bonding part, but the information regarding the latest distortion of a crimping | compression-bonding part cannot be acquired. Originally, the closest part of the crimping part is most likely to cause problems with the twisted PC steel wire, so the nearest part of the crimping part can measure the tension of the PC steel twisted wire (that is, measure the strain of the optical fiber). This is the desired part. On the other hand, in the PC steel stranded wire fixing portion structure 100, the optical fiber portion 20 passes through the optical fiber portion 20 between the inner wall surface of the crimping portion 30 and the PC steel stranded wire 3 from the end face of the PC steel stranded wire 1 with optical fiber. Therefore, it is possible to measure the tension of the optical fiber-attached PC steel stranded wire 1 up to the immediate vicinity of the crimping portion 30.

  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 a PC steel stranded wire 3 having 19 PC steel strands 4a to 4c as in the above-described embodiment, for example, a 7-stranded PC steel stranded wire, or other It can be similarly applied to PC steel stranded wires.

  In the fixing part structure 100 of the PC steel stranded wire according to the above embodiment, the PC steel stranded wire with optical fiber 1 whose periphery is crimped by the crimping part 30 at the front end part 1a may be prepared in the field, The optical steel-attached PC steel stranded wire 1 whose periphery is crimped by the crimping portion 30 at the front end portion 1a may be manufactured in advance at a factory.

  In the said embodiment, although the load-bearing body main body 57 had the two fixing | fixed parts 60, the number of the fixing | fixed parts 60 is not limited to this. Moreover, although the crimping | compression-bonding part 30 had the main-body part 31 and the insertion part 32, the structure of the crimping | compression-bonding part 30 is not limited to this. Moreover, although the two optical fiber main bodies 21 accommodated in the protective tube 25 as the optical fiber part 20 are arrange | positioned at the PC steel stranded wire 1 with an optical fiber, the number of the optical fiber parts 20 is not limited to this.

  Subsequently, as an embodiment of the measuring apparatus of the present invention, a measuring apparatus 70 for measuring the strain of the PC fiber stranded wire with optical fiber 1 will be described.

  FIG. 6 is a block diagram illustrating an example of a measurement apparatus. As shown in FIG. 6, the measuring device 70 is a type of measuring device that inputs and outputs laser light from both ends of the optical fiber strand 23. The measuring device 70 is connected to an optical signal transmitter 73 that transmits an optical signal to one rear end 23c of a pair of optical fiber wires 23 connected to each other at the front ends 23a and 23b, and to the front ends 23a and 23b. An optical signal receiving unit 74 that receives an optical signal from the other rear end 23d of the pair of optical fiber strands 23, and an optical signal received by the optical signal receiving unit 74 to analyze a PC steel twisted optical fiber An analysis unit 71 that acquires the distortion of the line 1 and a display unit 72 that displays the strain state acquired by the analysis unit 71 are provided.

  The optical signal transmitter 73 and the optical signal receiver 74 may be configured as an integrated measuring device, for example. The analysis unit 71 is a computing device such as a computer, for example, and the display unit 72 is a display monitor that displays a computation result by the computing device, for example. You may employ | adopt the personal computer etc. which are provided with the analysis part 71 and the display part 72 integrally. The optical signal transmitter 73, the optical signal receiver 74, and the optical fiber strand 23 are appropriately connected through an optical branching device 75, a coupler, and the like. The details of the measuring device of the method shown in FIG. 6 are disclosed in, for example, Japanese Patent No. 5192742. Specifically, the strain generated in each position in the longitudinal direction of the PC steel stranded wire 3 is indirectly measured by measuring the longitudinal strain distribution of the optical fiber strand 23 based on the input / output optical signals. Can know.

  According to this measuring apparatus 70, an optical signal is transmitted to one rear end 23 c of the optical fiber 23 by the optical signal transmitter 73, and the other rear of the optical fiber 23 is transmitted by the optical signal receiver 74. An optical signal from the end 23d can be received. Therefore, since a pair of optical signal transmitters 73 and optical signal receivers 74 is sufficient for a pair of two optical fiber strands 23, the optical signal transmitters 73 and optical signal receivers for the number of optical fiber strands 23 are sufficient. The number of parts 74 can be reduced.

  Then, the example of the measuring method for measuring the distortion of the said PC steel twisted wire 3 is demonstrated as embodiment of the measuring method of this invention.

(Preparation process)
The ground anchor 50 described above is prepared, and a plurality of the ground anchors 50 are installed on the slope. At this time, a ground anchor 50 having a PC steel stranded wire fixing part structure 100 is prepared. Specifically, the optical fiber portion 20 is peeled off from the optical steel-attached PC steel stranded wire 1, and the optical fiber main body 21 is accommodated in the protective tube 25. In this way, at least a pair of optical fiber portions 20 in which the optical fiber main body 21 is accommodated in the protective tube 25 are prepared. And in the anchor body long part 55 of the ground anchor 50, in the state in which the optical fiber main body 21 was accommodated in the protective tube 25 in the state in which the optical fiber main body 21 was accommodated in one PC steel twisted wire 1 with an optical fiber, PC steel. It installs in the twist 3a of the stranded wire 3. The pair of optical fiber main bodies 21 are pulled out from the end face of the front end portion 1a (see FIG. 4) of the PC steel stranded wire 1 with an optical fiber, and the optical fiber main bodies 21 are connected to each other at the front end portion 1a to double the length. A reciprocating optical fiber unit 20 is used.

(Connection process)
Next, in the front end portion 1a of the PC steel stranded wire with optical fiber 1 (see FIGS. 4 and 6), the front end portions 23a and 23b of the optical fiber strands 23 of the pair of optical fiber portions 20 are connected to each other. Further, in the rear end portion 1b (see FIG. 6) of the PC steel stranded wire 3, one of the pair of optical fiber wires 23 in which the optical signal transmitting portion 73 that transmits an optical signal is connected to the front end portions 23a and 23b. To the rear end 23c. At the rear end portion 1 b of the PC steel stranded wire 3, an optical signal receiving portion 74 that receives an optical signal is connected to the other rear end portion 23 d of the pair of optical fiber strands 23. Thereby, the one optical fiber part 20 and 20 which reciprocates the substantially full length of PC steel twisted wire 1 with an optical fiber is formed.

(Measurement process)
Then, using the measuring device 70, the optical signal received by the optical signal receiving unit 74 is analyzed by the analyzing unit 71 to obtain information (strain distribution) on the strain of the PC steel stranded wire with optical fiber 1, and the ground on the slope is obtained. Measure the strain inside. Thereby, the distribution of strain at each location corresponding to the entire length of the optical fiber portions 20 and 20 is measured. Here, the strain distribution in the first half portion and the strain distribution in the second half portion of the optical fiber portions 20, 20 indicate strains at symmetrical positions sandwiching the central axis A of the PC steel stranded wire 3. Therefore, for example, when there is a portion where the PC steel stranded wire 3 is bent, information on both the strain inside the bent portion and the strain outside the bent portion can be obtained. Therefore, the strain state of the PC steel stranded wire 3 can be known more accurately by using such information of two strain distributions. In addition, as above-mentioned, the distortion state of PC steel twisted wire 3 can also be known in detail by installing not only a pair but two or more pairs of optical fibers.

  As described above, according to this installation step, the ground anchor 50 installed on the slope can measure the reciprocal strain distribution, so that the optical signal transmitter 73 is connected to one of the optical fiber strands 23. By connecting the optical signal receiving unit 74 to the other rear end portion 23d of the optical fiber 23 by connecting to the rear end portion 23c, the underground strain on the slope can be easily measured. At this time, since the two optical fiber portions 20 can be pulled out from the end surface of the front end portion 1a of the PC steel stranded wire with optical fiber 1 as described above, the pair of optical fiber strands 23 are connected to each other on the front end portion 1a side. Connection work can be easily performed.

  In the measurement method of the above-described embodiment, an example in which the number of the optical fiber strands 23 is one to two is shown. However, the number is not limited to this example, and the number of the optical fiber strands 23 may be a desired number.

  DESCRIPTION OF SYMBOLS 1 ... PC steel twisted wire with optical fiber, 1a ... Front end part, 1b ... Rear end part, 3 ... PC steel twisted wire, 3a ... Twist, 4a-4c ... PC steel strand, 5 ... Filler, 20 ... Light Fiber part, 23 ... Optical fiber, 23a, 23b ... Front end part, 23c, 23d ... Rear end part, 25 ... Protection tube, 30 ... Crimping part, 31d, 32d ... Inner wall surface, 50 ... Ground anchor, 56 ... Load resistance , 60 ... fixing part, 70 ... measuring device, 71 ... analyzing part, 73 ... optical signal transmitting part, 74 ... optical signal receiving part, 100 ... fixing structure of PC steel stranded wire, 101 ... structure, 103 ... fixing Hole, R ... Rock (fixed part).

Claims (6)

A PC steel stranded wire with an optical fiber having a PC steel stranded wire formed by twisting a plurality of PC steel strands and having a spiral fold, and an optical fiber portion installed at the fold, It is a fixing part structure of PC steel stranded wire with optical fiber to be fixed to,
A load-bearing body that is provided in a fixing hole cut in the fixing portion and fixes the PC steel stranded wire with an optical fiber to the fixing hole via a filler filled in the fixing hole;
A fixing portion that is provided on the load bearing body and fixes the PC steel stranded wire with an optical fiber fixed to the load bearing body to the load bearing body,
The fixing part is
A crimping part that is crimped around the PC steel stranded wire with optical fiber at the front end of the PC steel stranded wire with optical fiber;
The optical fiber portion is
A PC steel twist, comprising: an optical fiber strand disposed in the twisted line; and a protective tube disposed between the inner wall surface of the crimping portion and the PC steel twisted wire and accommodating the optical fiber strand. Wire fixing part structure.   2. The PC steel stranded wire fixing portion structure according to claim 1, wherein the protective tube has a yield strength higher than a yield strength of the crimping portion. The PC steel stranded wire with optical fiber has at least a pair of the optical fiber strands,
The pair of optical fiber strands is a PC steel stranded wire fixing portion structure according to claim 1 or 2, wherein the pair of optical fiber strands are connected to each other at a front end portion of the optical fiber-attached PC steel stranded wire.   The ground anchor which has the fixing | fixed part structure of the PC steel twisted wire as described in any one of Claims 1-3. A measuring device for measuring strain of a PC steel stranded wire with an optical fiber in the fixing portion structure of the PC steel stranded wire according to any one of claims 1 to 3,
An optical signal transmitter that transmits an optical signal to one rear end of the optical fiber wires connected to each other at the front end;
An optical signal receiver that receives an optical signal from the other rear end of the optical fiber wire connected to each other at the front end;
An analysis unit comprising: an analysis unit that analyzes the optical signal received by the optical signal reception unit and acquires information related to distortion of the PC steel stranded wire with optical fiber. Preparing a ground anchor having a fixing structure of a PC steel stranded wire according to claim 3, and preparing a plurality of ground anchors on a slope;
An optical signal transmitting part for transmitting an optical signal is connected to one rear end part of the optical fiber strands connected to each other at a front end part of the PC steel stranded wire with optical fiber and receives an optical signal. Connecting the receiving unit to the other rear end of the optical fiber wires connected to each other at the front end; and
A measurement step of analyzing the optical signal received by the optical signal reception unit by an analysis unit to obtain information on the strain of the PC steel stranded wire with an optical fiber, and measuring the underground strain on the slope; A measuring method.

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