JP4174034B2 - PC grout filling degree detection method and apparatus - Google Patents

Description

  The present invention relates to a method for inspecting a prestressed concrete (PC) structure, and more particularly to a PC grout filling degree detection method and apparatus suitable for evaluating the filling degree of a PC grout filled in a PC sheath tube in a post tension system.

  The PC method for forming a PC structure can be roughly divided into a pre-tension method and a post-tension method depending on how stress is applied to concrete. In the pre-tension method, a PC steel material to which tension is applied is placed in a concrete formwork, and concrete is placed around the PC steel material. When the concrete is consolidated, the tension applied to the PC steel material is released. Thereby, the prestress by PC steel materials trying to shrink is given to concrete.

  On the other hand, in the post-tension method, a concrete tube is placed by placing a sheath tube through which a PC steel material passes in a mold. When the concrete is solidified, the PC steel material is passed through a PC sheath tube (hereinafter sometimes simply referred to as a sheath tube), and tension is applied to the PC steel material. Furthermore, in order to integrate the PC steel material and the concrete while applying tension to the PC steel material, and to prevent the corrosion of the PC steel material, the inside of the sheath tube is filled with a grout material (PC grout) such as mortar. And if a grout material solidifies, the tension | tensile_strength which was given to PC steel material will be open | released, and prestress will be given to concrete.

  As described above, in the post-tension type PC method, the PC sheath tube is filled with PC grout such as mortar (hereinafter sometimes simply referred to as grout). When the PC sheath tube is not sufficiently filled with PC grout and there are voids in the sheath tube, the PC steel material can not only give sufficient prestress to the concrete, but also the PC steel material. May corrode and break. For this reason, conventionally, the grout filling state in the sheath tube has been inspected.

Conventionally, the grout filling state of the PC sheath tube is generally examined by the following method.
(A) Method of observing the filling degree by making a hole in the sheath tube (perforation method): This method is a method of drilling from the concrete surface with a drill to make a hole in the PC sheath tube, and whether or not the PC grout is filled. This is a direct observation method.
(B) Method of detecting a temperature difference by infrared rays (infrared ray method): This method uses the fact that when an air layer is present in concrete, temperature distribution occurs because air serves as a heat insulating material. . That is, if there is an air pocket in the sheath tube because the grout filling amount is small, the surface temperature of the portion corresponding to the air pool becomes high when the concrete surface is heated by sunlight or the like. Conversely, when heat is radiated from the concrete at night or the like, the surface temperature of the portion corresponding to the air pool becomes low. Using this property, the surface temperature of concrete is detected by infrared rays to evaluate the degree of filling of the grout.
(C) Ultrasonic method (ultrasonic method): This method is a method in which ultrasonic waves are incident on the concrete from the surface of the concrete and the voids in the sheath tube are detected by the reflected waves.
(D) Method by hammering sound (sounding method): In this method, a sound wave is applied to one end of a PC steel material by striking or the like, and this is received at the other end. This is a method for determining whether or not there is any.
(E) X-ray transmission imaging method (X-ray transmission method): This method is a structure in which X-rays are irradiated from one side of a concrete structure and a photosensitive film or imaging plate is placed on the opposite side of the structure. This is a method of determining the presence or absence of voids by visualizing the inside of an object.
(F) Two-element radar method (two-element radar method): This method uses a ground radar equipped with a pair of transmitting and receiving antennas to radiate radio waves from the surface of the concrete into the concrete and reflect information from the inside of the concrete. This is a method for detecting defects by imaging.

In recent years, an optical fiber is disposed inside the PC sheath tube, and the temperatures before and after the PC grout is injected into the sheath tube are continuously measured along the longitudinal direction of the sheath tube. A method for evaluating the degree of filling of grout from the difference has been proposed (Patent Document 1). Furthermore, a method of detecting the degree of filling of the grout by irradiating a neutron beam having a large penetrating power from one side of the PC structure and detecting a neutron transmitted to the opposite side of the structure or a backscattered neutron to the neutron source side Has also been proposed (Patent Document 2).
Japanese Patent Laid-Open No. 11-14573 JP 2001-41908 A

  Each of the above methods for detecting the degree of filling of the grout has the following drawbacks. First, in the drilling method (a), only the filling degree at the position where the hole is drilled can be detected, and the entire length of the sheath tube cannot be inspected. In the case of an existing PC structure, the position of the sheath tube needs to be confirmed by nondestructive inspection before drilling a hole because the position of the sheath tube is not known from the concrete surface in the case of an existing PC structure. Moreover, since the perforation method is performed by making holes in hard concrete, it takes time to inspect one place.

  The infrared method (b) can be detected when the air layer (void) present in the concrete is close to the surface of the concrete, and there is 20 cm of concrete on the PC sheath tube like a general PC floor slab. It cannot be applied to such structures. Moreover, it is necessary to measure when the concrete is heated and when it is cooled, so that the inspection time is limited. Furthermore, the infrared method cannot be measured in places where the concrete is not heated, such as the north side of a mountain that is not exposed to sunlight.

  Since the ultrasonic method (c) requires measurement immediately above the sheath tube, it is necessary to grasp the position of the reinforcing bar and the position of the sheath tube in advance by a ground penetrating radar or the like. Moreover, in order to measure the whole surface of concrete by point measurement, the measurement in a huge number of measurement points is required, and a lot of measurement time is required. In the sound-drum method (d), it is necessary to apply a sound wave (vibration) to each sheath tube, and much time is required for the inspection. Further, since the sound-striking method detects and determines the sound wave applied to one end of the PC steel material at the other end, it cannot grasp which portion in the longitudinal direction of the sheath tube is insufficiently filled.

  The X-ray transmission method of (e) is subject to the application of the ionizing radiation injury prevention regulations in order to use X-rays, and it is necessary to secure a management area at the work site and to perform safety management by the X-ray work supervisor. Further, since the X-ray transmission method needs to transmit X-rays to the opposite side of the PC structure, when the PC structure is thick, it cannot be detected even if the sheath tube is near the concrete surface. . In a large structure, it is difficult to attach an X-ray film on the back surface opposite to the X-ray source, and a lot of manpower and time are required. Furthermore, in the X-ray transmission method, when there is a sheath tube immediately below the reinforcing bar, the sheath tube cannot be detected because the reinforcing bar image and the sheath tube image overlap each other. In the X-ray transmission method, the photographed film needs to be taken back and developed, and cannot be determined on site. In addition, the two-element radar method of (f) evaluates the inspection result by using a vertical cross-sectional image, so that it is possible to detect the reinforcing bar and the PC sheath tube, but obtain information that can be detected until the grout is insufficiently filled. I can't.

  And the method (optical fiber temperature detection method) which detects temperature using the optical fiber of patent document 1 cannot be applied to the existing PC structure which has not arrange | positioned the glass fiber to a sheath pipe | tube. Further, in the optical fiber temperature detection method, it is necessary to place a glass fiber in each sheath tube and measure the temperature of each sheath tube one by one, which requires a lot of time for measurement. Moreover, since the optical fiber temperature detection method obtains the temperature difference between before and after the PC grout injection, it is necessary to adjust the grout so that the grout temperature is different from the temperature inside the sheath tube. There are time constraints.

  When the method using neutrons in Patent Document 2 (neutron beam method) is a transmission method, measurement cannot be performed when the PC structure is thick or where the detector cannot be disposed on the opposite side of the neutron source. Further, in the transmission method, it is necessary to move the neutron source and the detector arranged on both sides of the PC structure in correspondence with each other, and it is difficult to align the two. The scattering method using neutron backscattering is a static measurement method that cannot be continuously measured, and requires a lot of time and labor to measure the entire PC structure. To do.

  The present invention has been made in order to eliminate the above-mentioned drawbacks of the prior art, and an object thereof is to make it possible to easily and reliably detect the degree of filling of the PC grout into the PC sheath tube.

In order to achieve the above object, a PC grout filling degree detection method according to the present invention radiates a plurality of transmission waves along the longitudinal direction of a PC sheath tube in a PC structure, and uses the plurality of transmission waves. receiving a plurality of reflected waves determined the distribution of the reflection intensity in the PC structure in, on the basis of the reflection intensity distribution, as viewed in the longitudinal direction of the P C sheath tube by superimposing the plurality of reflected wave A fluoroscopic image is created, and the filling degree of the PC grout into the PC sheath tube is detected from the fluoroscopic image. It is desirable to create a fluoroscopic image for each predetermined length along the longitudinal direction of the PC sheath tube.

A PC grout filling degree detection apparatus for carrying out the filling degree detection method includes a plurality of transmission antennas that radiate a plurality of transmission waves along the longitudinal direction of the PC sheath tube in the PC structure, A plurality of reception antennas for receiving reflected waves from the PC structure of the transmission wave radiated from the transmission antenna, and at least one of the transmission antennas and the reception antenna along the surface of the PC structure Based on the reflected wave received by each of the receiving antennas and the detection signal of the position detecting unit, the moving unit for moving the moving unit, the position detecting unit for detecting the position of the moving unit, and the detection signal of the position detecting unit. with obtaining the reflection intensity distribution of the transmitted wave, based on the reflection intensity distribution obtained, the longitudinal direction of the PC sheath tube of the PC structure in by superimposing the plurality of reflected wave It is characterized by having a fluoroscopic image creation unit for obtaining the fluoroscopic image as seen in. The fluoroscopic image creation unit may be configured to create a fluoroscopic image for each predetermined length direction along the longitudinal direction of the PC sheath tube.

  In the present invention as described above, after obtaining the reflection intensity with respect to the transmission wave in the PC structure, it is converted into a fluoroscopic image viewed in the longitudinal direction of the sheath tube. For this reason, since a signal corresponding to the received reflected wave (reception signal) is superimposed and synthesized along the longitudinal direction of the sheath tube, whether the reception signal is strengthened and there is a void in the sheath tube, that is, The degree of filling of PC grout into the PC sheath tube can be detected and evaluated easily and reliably. Then, by obtaining a fluoroscopic image for each predetermined length (for example, every 20 to 50 cm) along the longitudinal direction of the sheath tube, it is possible to easily grasp which position of the sheath tube is insufficiently filled with grout. Can do. Note that radio waves or ultrasonic waves can be used as the transmission wave.

Preferred embodiments of a PC grout filling degree detection method and apparatus according to embodiments of the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is a schematic block diagram of a PC grout filling degree detection apparatus according to an embodiment of the present invention. In FIG. 1, the filling degree detection apparatus 10 has a transmission / reception unit 14 mounted on a moving carriage 12 which is a moving means. The movable carriage 12 is an example provided with wheels 16 and is, for example, a hand-drawn carriage, which can freely move on the PC structure. A rotary encoder 18 is attached to any one of the wheels 16 so that the moving distance of the moving carriage 12 can be detected. Note that the mobile carriage may be self-propelled.

  The transmission / reception unit 14 includes a plurality of transmission antennas 20 and a plurality of reception antennas 22 and is configured as an array antenna. That is, as shown in FIG. 2, the transmission / reception unit 14 has a structure in which the transmission antennas (T) 20 and the reception antennas (R) 22 are alternately and linearly arranged. Further, in the case of the embodiment, the transmission / reception unit 14 includes two rows of a front row 26 and a rear row 28, and each row has a structure in which a plurality of transmission antennas 20 and a plurality of reception antennas 22 are alternately arranged. ing. In the case of the embodiment, in the front row 26 and the rear row 28, the positions of the antennas 20 and 22 are shifted by about half along the row, and the reflected waves (echoes) having different positions or reflection angles in the front row 26 and the rear row 28. ) Can be detected.

  The transmission / reception unit 14 configured as described above is arranged so that the rows 26 and 28 are parallel to the axis of the PC sheath tube when the degree of filling of the PC grout into the PC sheath tube is inspected, and an arrow 30 in FIG. As shown in FIG. 4, the movement is made in the direction orthogonal to the rows 26 and 28. That is, the movable carriage 12 is arranged on the PC floor slab 32 which is the PC structure shown in FIG. 2 and is moved in a direction orthogonal to the axis of the PC sheath tube 34. In the embodiment, the PC floor slab 32 is provided with an upper bar arrangement 38 and a lower bar arrangement 40 at the upper and lower portions in the concrete 36. The upper bar arrangement 38 and the lower bar arrangement 40 are each formed by assembling a large number of reinforcing bars 42 in a lattice pattern. The PC sheath tube 34 is disposed between the upper bar arrangement 38 and the lower bar arrangement 40. The PC sheath tube 34 is formed of a resin such as polyethylene or hard vinyl chloride, and has a PC steel material made of a bar steel or wire strand disposed therein, and is filled with a PC grout such as mortar.

  As shown in FIG. 1, the filling degree detection device 10 includes a carriage position calculation unit 50 to which an output signal (pulse) of the rotary encoder 18 is input. The carriage position calculation unit 50 constitutes position detection means together with the rotary encoder 18, obtains the travel distance of the movable carriage 12 based on the output signal of the rotary encoder 18, and obtains the current position of the movable carriage 12 with respect to the reference position. . Further, the filling degree detection device 10 includes a trigger pulse generator 52 to which an output signal of the rotary encoder 18 is input. The trigger pulse generator 52 has an oscillation control unit 54 and a switching control unit 56 connected to the output side. The trigger pulse generator 52 counts the pulses output from the rotary encoder 18 and gives a trigger pulse to the oscillation control unit 54 and the switching control unit 56 every predetermined number of pulses.

  The oscillation control unit 54 controls the driving of the oscillator 58 and controls the oscillation frequency (frequency of the transmission wave) of the oscillator 58. The oscillator 58 is connected to the directional coupler 60 on the output side, and outputs a high-frequency signal as a transmission wave to the directional coupler 60. The directional coupler 60 outputs a part of the high-frequency signal output from the oscillator 58 to the echo extraction unit 62 described later in detail, and outputs the other part to the transmission amplifier 64. The transmission amplifier 64 amplifies the signal from the directional coupler 60 and supplies the amplified signal to the transmission antenna 20 via the transmission switching unit 66. The transmission antenna 20 radiates the high frequency radio wave output from the amplifier 64 into the PC floor slab 32 as a transmission wave.

  When the trigger pulse is input from the trigger pulse generator 52, the switching control unit 56 generates an antenna switching signal and gives it to the transmission switching unit 66 and the signal processing unit 70. In the transmission switching unit 66, the switching elements are switched by the antenna switching signal input from the switching control unit 56, the plurality of transmission antennas 20 are sequentially connected to the amplifier 64, and the high frequency signal output from the amplifier 64 is given to the transmission antenna 20.

  Each receiving antenna 22 receives a reflected wave (echo) of the transmitted wave from the PC floor slab 32 and outputs a received signal corresponding to the intensity of the received reflected wave to the echo extraction unit 62. On the output side of the echo extraction unit 62, a signal processing unit 70, which will be described in detail later, is provided. The signal processing unit 70 creates a three-dimensional image inside the PC floor slab 32 and a fluoroscopic image viewed in the longitudinal direction of the PC sheath tube 34 based on the output signal of the echo extraction unit 62 and displays it on the display unit 72. To do.

  As shown in FIG. 3, the echo extraction unit 62 includes reception amplifiers 74 (74a to 74n) corresponding to the plurality of reception antennas 22 (22a to 22n). A mixer 76 (76a to 76n) is provided on the output side of each amplifier 74. Each mixer 76 receives the high-frequency signal output from the oscillator 58 from the directional coupler 60 and multiplies the high-frequency signal by the output signal from the amplifier 74 to generate an intermediate frequency (IF) signal. To the corresponding IF amplifier 78 (78a to 78n) provided on the output side. An A / D converter 80 (80a to 80n) is provided on the output side of each IF amplifier 78. The A / D converter 80 converts the analog signal output from the IF amplifier 78 into a digital signal, and sends it as an output signal of the echo extraction unit 62 to the reflection intensity detection unit 82 of the signal processing unit 70.

  The signal processing unit 70 includes a reflection intensity detection unit 82, a channel memory 84, a three-dimensional image creation unit 86, and a perspective image creation unit 88. The reflection intensity detection unit 82 includes a reflection intensity calculator 92 (92a to 92n) provided corresponding to the A / D converter 80 of the echo extraction unit 62. The reflection intensity calculator 92 receives the output signal of the A / D converter 80, the position information of the mobile carriage 12 obtained by the carriage position calculator 50, and the antenna switching signal output by the switching controller 56. And enter. Then, each reflection intensity calculator 92 obtains the reflection intensity for the internal transmission wave at each point of the PC floor slab 32 corresponding to the depth based on these input signals. The channel memory 84 provided on the output side of the reflection intensity detector 82 indicates the reflection intensity obtained by each reflection intensity calculator 92 in accordance with each reflection intensity calculator 92, that is, each receiving antenna 22. It is stored as data together with position and depth information.

  The three-dimensional image creation unit 86 reads the data written in the channel memory 84 and performs synthetic aperture processing to obtain a three-dimensional image that becomes a reflection intensity distribution in the PC floor slab 32. The fluoroscopic image creation unit 88 is provided on the output side of the 3D image creation unit 86, and in the longitudinal direction (axial direction) of the PC sheath tube 34 based on the 3D image obtained by the 3D image creation unit 86. Find the seen fluoroscopic image. The fluoroscopic image creation unit 88 can obtain a fluoroscopic image for each desired length along the longitudinal direction of the PC sheath tube 34. Then, the fluoroscopic image creation unit 88 outputs the obtained fluoroscopic image to the display unit 72 and displays it.

  The inspection and evaluation of the filling degree of the PC grout to the PC sheath tube 34 by the filling degree detection apparatus 10 according to the embodiment will be described based on the flowchart of FIG. In the following description, inspection of a PC floor slab will be described as an example.

  First, as shown in step 100 of FIG. 4, the inspection range of the PC floor slab 32 is set. Next, a reference point (reference position) serving as an origin is determined, and a measurement line (not shown) is marked in the set inspection range (step 102). That is, a line for moving (running) the movable carriage 12 is drawn on the surface of the PC floor slab 32. This measurement line is marked so as to be orthogonal to the PC sheath tube 34 arranged in the PC floor slab 32 (see FIG. 2). Thereafter, the movable carriage 12 shown in FIG. 1 is moved along the measurement line, and measurement is performed by the movable carriage 12 (step 104). The measurement by the movable carriage 12 is performed as follows.

  When the movable carriage 12 is moved along the measurement line, the rotary encoder 18 rotates with the rotation of the wheel 16 and outputs a pulse for each predetermined rotation angle. The carriage position calculation unit 50 reads a pulse output from the rotary encoder 18, calculates the movement amount (travel distance) of the moving carriage 12, and calculates the position of the moving carriage 12 with respect to the reference point. Then, the carriage position calculation unit 50 gives the obtained position of the mobile carriage 12 to each reflection intensity calculator 92 constituting the reflection intensity detection unit 82 of the signal processing unit 70 as shown in FIG.

  On the other hand, the trigger pulse generator 52 counts the pulses output from the rotary encoder 18, and when a predetermined count value, for example, the number of pulses corresponding to a moving amount of 1 cm of the movable carriage 12 is reached, the trigger pulse generator 52 generates the trigger pulse. To the switching control unit 56 to reset a counter (not shown). The oscillation controller 54 drives the oscillator 58 in synchronization with the trigger pulse output from the trigger pulse generator 52 and causes the oscillator 58 to output a high frequency signal. The high-frequency signal output from the oscillator 58 is input to the directional coupler 60, part of which is supplied to each mixer 76 of the echo extraction unit 62, and the other part is input to the amplifier 64. The amplifier 64 amplifies the high frequency signal from the directional coupler 60 and inputs the amplified signal to the transmission switching unit 66.

  When the trigger pulse is input from the trigger pulse generator 52, the switching control unit 56 generates an antenna switching signal and inputs the antenna switching signal to the signal processing unit 70, and gives the transmission switching unit 66 to control the transmission switching unit 66. The plurality of transmission antennas 20 are sequentially switched and connected to the amplifier 64. As shown in FIG. 5, the transmission antenna 20 connected to the amplifier 64 radiates a high-frequency signal output from the amplifier 64 into the PC floor slab 32 as a transmission wave (transmission signal) 120. A part of the transmission wave 120 propagating inside the PC floor slab 32 is reflected by the reinforcing bar 42 and the PC sheath tube 34 and returns to the incident direction of the transmission wave 120 as a reflected wave (reflected signal) 124 (124a, 124b). come.

  As shown in FIG. 5A, when the PC grout 126 is filled in the PC sheath tube 34, the reflection coefficient from the PC sheath tube 34 is reduced, and the reflection intensity (reflection) is reflected as in the reflected wave 124a. The strength of the wave) is reduced. On the other hand, as shown in FIG. 2 (2), when the PC sheath 126 is not filled with the PC grout 126 and the gap 128 is formed in the PC sheath 34, the PC sheath The reflection coefficient of the tube 34 is large, and the intensity of the reflected wave 124b from the PC sheath tube 34 is increased. Therefore, by analyzing the intensity of the reflected wave 124, the filling degree of the PC grout 126 inside the PC sheath tube 34 can be detected and evaluated.

  The reflected wave 124 from the PC sheath tube 34 is received by each receiving antenna 22. Each reception antenna 22 inputs an electric signal corresponding to the intensity of the received reflected wave 124 to the corresponding amplifier 74 of the echo extraction unit 62 as a reception signal. Each amplifier 74 amplifies the received signal and sends it to the corresponding mixer 76. The mixer 76 mixes (multiplies) the high-frequency signal input from the directional coupler 60 and the output signal of the amplifier 74 and outputs an intermediate frequency signal (IF signal) to the A / D converter 80 provided on the output side. . The A / D converter 80 converts the analog IF signal amplified by the IF amplifier 78 into a digital signal and sends the digital signal to the reflection intensity detection unit 82 of the signal processing unit 70. The A / D converter 80 may receive an antenna switching signal output from the switching control unit 56 and perform A / D conversion in synchronization with the antenna switching signal.

  Each reflection intensity calculator 92 of the reflection intensity detector 82 receives the output signal of the corresponding A / D converter 80, and the position of the mobile carriage 12 obtained by the carriage position calculator 50 as described above, An antenna switching signal output from the switching control unit 56 is input. Then, the reflection intensity calculator 92 calculates the position of each receiving antenna 22 with respect to the reference position based on the position information of the moving carriage 12 obtained by the carriage position calculator 50. Further, the reflection intensity calculator 92 calculates the reflection intensity in the depth direction in the PC floor slab 32 based on the antenna switching signal output from the switching controller 56 and the signal input from the A / D converter 80. Calculate according to the position. That is, the reflection intensity calculator 92 determines the depth at which the transmission wave is reflected based on the time difference from when the transmission antenna 20 radiates the transmission wave to when the reception antenna 22 receives the reflection wave. Then, the reflection intensity calculator 92 writes the calculated intensity of the reflected wave in the channel memory 84. The channel memory 84 stores the intensity of the reflected wave 124 obtained by each reflection intensity calculator 92 in correspondence with the position information of the receiving antenna 22 and the depth information of the PC floor slab 32.

  When the measurement with the mobile carriage 12 is completed, the filling degree is evaluated. That is, when an image creation command is given to the signal processing unit 70 via an input unit (not shown), the 3D image creation unit 86 reads the reflection intensity data stored in the channel memory 84. Then, the three-dimensional image creation unit 86 performs a synthetic aperture process on the receiving antenna 22 (step 106 in FIG. 4), obtains the distribution of the reflection intensity in the PC floor slab 32, and is translucent according to the intensity of the reflected wave 124. Are generated (step 108) and output to the fluoroscopic image generator 88.

  The fluoroscopic image creation unit 88 is arranged along the longitudinal direction of the PC sheath tube 34 from the three-dimensional image in the PC floor slab 32 created by the three-dimensional image creation unit 86 based on a preliminarily given fluoroscopic image creation condition. Then, three-dimensional image information for each set predetermined length (for example, every 20 to 50 cm) is cut out, and a fluoroscopic image viewed in the axial direction of the PC sheath tube 34 is created (steps 110 and 112). Output and display. As a result, when the intensity of the reflected wave 124 along the longitudinal direction of the PC sheath tube 34 is received by each receiving antenna 22 as shown in FIG. The reflected waves 124 in the longitudinal direction are superposed to form a composite signal 130 as shown in FIG. For this reason, in the fluoroscopic image (not shown) displayed on the display unit 72, the image of the PC steel material 122 is darkly colored according to the intensity of the composite signal 130 and is marked. The display unit 72 is configured so that when the PC sheath tube 34 is filled with the PC grout 126, the intensity of the reflected wave 124 from the PC sheath tube 34 is weak, so that the PC sheath tube 34 is hardly displayed in the fluoroscopic image. It has been adjusted.

  The operator confirms the positions of the reinforcing bars 42 and the PC sheath tube 34 from the bar arrangement diagram and the side surface of the PC floor slab 32 (step 114). Then, the operator determines the degree of filling of the PC grout 126 into the PC sheath tube 34 based on the fluoroscopic image displayed on the display unit 72 (step 116). When a PC sheath tube 34 with an insufficient degree of filling of the PC grout 126 is found, a fluoroscopic image in which the axial length of the PC sheath tube 34 is made shorter is created, so that the position of underfilling can be more accurately determined. I can grasp it.

  As described above, in the embodiment, the PC sheath tube 34, that is, the PC steel material 122 is detected by the transmission / reception unit 14 including the array antenna, and therefore the PC sheath tube 34 is directly under the reinforcing bar 42. Even if it exists, it becomes possible to detect it easily and reliably, without being disturbed by the reinforcing bar 42. In addition, a fluoroscopic image seen in the longitudinal direction (axial direction) of the PC sheath tube 34 is created, and the superimposed signal 130 is obtained by superimposing the reflected waves 124, and the image is colored according to the strength of the superimposed signal 130. The filling degree of the PC grout 126 can be easily evaluated without requiring a complicated determination operation. Further, since the inside of the PC floor slab 32 can be displayed as an image on the site, the filling degree can be evaluated immediately after the injection of the PC grout 126. In the case of insufficient injection, the PC grout 126 can be evaluated before solidifying. The grout 126 can be refilled and repaired. Then, the existing PC structure can be inspected to detect the location of the insufficiently injected portion of the PC grout 126, and the location to be repaired can be detected easily and accurately.

  In the embodiment, the case where the transmission wave is a radio wave has been described. However, an ultrasonic wave or the like may be used. In the embodiment, the case where the operator evaluates the filling degree of the PC grout 126 into the PC sheath tube 34 has been described. However, the signal processing unit 70 is provided with an evaluation unit for filling degree, and is based on experiments and simulations. Thus, color-coded display may be performed according to the degree of filling.

It is a schematic block diagram of a PC grout filling degree detection apparatus according to an embodiment of the present invention. It is explanatory drawing of the transmission / reception part which concerns on embodiment. It is a detailed block diagram of the echo extraction part and signal processing part which concern on embodiment. It is a flowchart which shows an example of the procedure of the filling degree evaluation by the filling degree detection apparatus which concerns on embodiment. It is explanatory drawing of the reflected wave by the difference in the filling degree of PC grout. It is a figure explaining the superimposition of the reflected wave in the fluoroscopic image which concerns on embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ......... Filling degree detection apparatus, 12 ......... Moving means (moving cart), 14 ......... Transmission / reception unit, 18, 50 ...... Position detecting unit (rotary encoder, cart position calculation unit), 20 ......... Transmitting antenna, 22 ......... receiving antenna, 32 ......... PC structure (PC floor), 34 ......... PC sheath tube, 58 ......... oscillator, 60 ...... directional coupler, 62 ......... Echo extraction unit 70... Signal processing unit 72... Display unit 82... Reflection intensity detection unit 86... 3D image creation unit 88. ... Transmitted wave, 122 ... PC steel, 124a, 124b ... Reflected wave, 126 ... PC grout, 128 ... Air gap.

Claims (4)

Radiating a plurality of transmission waves along the longitudinal direction of the PC sheath tube in the PC structure, receiving a plurality of reflected waves by the plurality of transmission waves, obtaining a reflection intensity distribution in the PC structure, based on the reflection intensity distribution, the create a fluoroscopic image as seen in the longitudinal direction of the P C sheath tube by superimposing the plurality of reflected waves, the degree of filling of the said PC sheath tube PC grout from the fluoroscopic image A method for detecting a filling degree of a PC grout, comprising detecting the filling degree. In the method for detecting the degree of filling of PC grout according to claim 1,
The method for detecting a filling degree of a PC grout, wherein the fluoroscopic image is created for each predetermined length along a longitudinal direction of the PC sheath tube. A plurality of transmission antennas that radiate a plurality of transmission waves along the longitudinal direction of the PC sheath tube in the PC structure;
A plurality of receiving antennas for receiving reflected waves from the PC structure of the transmitting waves radiated by the transmitting antennas;
Moving means for moving at least one of the transmitting antennas and the receiving antenna along the surface of the PC structure;
A position detector for detecting the position of the moving means;
Wherein based on the detection signal of the position detector and the reflected waves each receive antenna receives, along with determining the reflection intensity distribution of the transmitted wave of the PC structure in, on the basis of the reflection intensity distribution obtained, the A fluoroscopic image creation unit for obtaining a fluoroscopic image seen in the longitudinal direction of the PC sheath tube in the PC structure by superimposing a plurality of reflected waves ;
A PC grout filling degree detecting device characterized by comprising: In the PC grout filling degree detection device according to claim 3,
The PC grout filling degree detection device, wherein the fluoroscopic image creation unit creates a fluoroscopic image for each predetermined length direction along a longitudinal direction of the PC sheath tube.

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