JP7062582B2 - Inspection hammer device and inspection method using it - Google Patents

Description

The present disclosure relates to an inspection hammer device and an inspection method using the same.

Conventionally, in the maintenance of concrete structures such as tunnels in railways and roads, tapping sound surveys have been conducted in order to grasp the floating and internal cavities of concrete that lead to the peeling of concrete pieces. In such a hitting sound investigation, an inspector hits a concrete surface with a hammer and listens to the hitting sound to empirically determine the floating of concrete and the existence of an internal cavity. However, since such a tapping sound survey largely depends on the skill level of the inspector at the site, the individual difference of the inspector is reflected in the inspection result, and the state of the concrete cannot be quantitatively grasped. Furthermore, it is difficult to efficiently investigate concrete structures over a wide area. Therefore, for example, an apparatus for objectively determining the state of a concrete structure has been proposed (see, for example, Patent Document 1).

Japanese Patent No. 3822802

However, in the above-mentioned conventional technique, it is necessary to carry a large device, and it is impossible for an inspector to easily carry it.

Here, an inspection hammer device that solves the problems of the conventional technique and is easy to carry, yet can accurately, objectively, and easily grasp the state of the concrete structure and the hammer device thereof. The purpose is to provide usage.

Therefore, the inspection hammer device is an inspection hammer device including a head, and the head includes a cylindrical main body, a sphere attached to the tip of the main body via an elastic member, and the above-mentioned head. It has a sound collecting device and an analyzer disposed in the main body and a display device attached to the rear end of the main body, and the sound collecting device is the main body generated by the sphere hitting an inspection target. The sound pressure inside is measured, and the analyzer analyzes the decay of the measured sound pressure based on the time history data of the measured sound pressure, determines the soundness as the state to be inspected, and displays the display. The device changes the display mode according to the state of the inspection target , the inspection target is a concrete surface, and the state of the inspection target is the presence or absence of an internal cavity of the concrete and the presence or absence of a defect leading to the peeling of the concrete. The attenuation of the sound pressure is the ratio of the maximum value of the sound pressure immediately after the impact to the value of the sound pressure after a predetermined time has elapsed after the impact. Is judged to be defective .

In still other inspection hammer devices, the display mode further includes display colors.

In the inspection method using the inspection hammer device, a cylindrical main body, a sphere attached to the tip of the main body via an elastic member, a sound collecting device and an analyzer arranged in the main body, and an analysis device. An inspection method using an inspection hammer device including a head having a display device attached to the rear end of the main body, wherein the sphere is hit against an inspection target to hit the inspection target, and the inspection is performed. The process of measuring the sound pressure in the main body generated by hitting the target by the sound collecting device and the attenuation of the measured sound pressure based on the time history data of the measured sound pressure are analyzed and the inspection is performed. The inspection target is a concrete surface, and the inspection includes a step of determining the soundness of the target by the analyzer and a step of changing the display mode of the display device according to the state of the inspection target. The target state includes the presence or absence of an internal cavity of the concrete and the presence or absence of a defect leading to the peeling of the concrete, and the sound pressure attenuation is the maximum value of the sound pressure immediately after the impact and the sound pressure after a predetermined time has elapsed after the impact. When the ratio exceeds the threshold value, the analyzer determines that the soundness is poor .

According to the present disclosure, the inspection hammer device can accurately, objectively, and easily grasp the state of the concrete structure while being easy to carry.

It is a conceptual diagram which shows the structure of the head of the inspection hammer device in this embodiment. It is a photograph of the prototype of the head of the inspection hammer device in this embodiment. It is a wiring diagram of the electronic circuit of the analyzer provided in the inspection hammer device in this embodiment. It is a photograph which shows the outline of the tapping sound test of a concrete surface in this embodiment. It is a figure which shows the spectrum of the sound pressure in the tapping sound test of the concrete surface in this embodiment. It is a figure which shows the time history data of the sound pressure in the tapping sound test of a concrete surface in this embodiment. It is a figure which shows the spectrum of the sound pressure in the tapping sound test using the inspection hammer device in this embodiment. It is a table which shows the example of the display mode of the display device of the inspection hammer device in this embodiment. It is a flowchart which shows the operation of the inspection hammer device in this embodiment.

Hereinafter, embodiments will be described in detail with reference to the drawings.

FIG. 1 is a conceptual diagram showing the configuration of the head of the inspection hammer device according to the present embodiment, FIG. 2 is a photograph of a prototype of the head of the inspection hammer device according to the present embodiment, and FIG. 3 is the present embodiment. It is a wiring diagram of the electronic circuit of the analyzer provided in the inspection hammer device in. In FIG. 1, (a) is a side perspective view, (b) is a front view, and in FIG. 2, (a) is a sphere, (b) is an elastic member, (c) is an urging member, and (d). ) Is the power supply, (e) is the whole, and in FIG. 3, (a) is a processing circuit, (b) is a recording circuit, and (c) is a display circuit.

In the figure, reference numeral 10 denotes a head portion of an inspection hammer device according to the present embodiment, which is also referred to as a hammer head, and is used by being attached to a tip portion of a hammer handle (not shown). The handle may be any general hammer handle, for example, a wooden handle or a metal handle such as steel. It should be noted that the inspector can directly grasp the head 10 itself with his / her hand without using the handle, but here, for convenience of explanation, the head 10 is attached to the tip of the handle of the hammer. The case where it is used will be described.

The inspection hammer device according to the present embodiment is preferably used for detecting an internal cavity or a defect leading to peeling on the concrete surface of a concrete structure such as an inner wall surface of a tunnel in a railway, a road or the like. .. For example, an inspector grasps the handle with his / her hand, shakes the inspection hammer device, and strikes the tip of the head 10 against the concrete surface of the concrete structure to hit the concrete surface, which is generated at that time. It is used to analyze the tapping sound and quantitatively inspect the condition of the concrete structure to detect the defect. The inspection target of the inspection hammer device is not necessarily limited to the inner wall surface of the tunnel in railways, roads, etc., and may be any kind of concrete structure, and may be a concrete surface. For example, it may be the surface of any part of the concrete structure. Further, the inspection hammer device may be used to confirm the fixing status of additives such as signs attached to the concrete surface.

In this embodiment, the upper, lower, left, right, front, rear, and other directions used to explain the configuration and operation of each part of the head 10 of the inspection hammer device and other members are shown. The expression is relative rather than absolute and is appropriate when each part of the head 10 and other members are in the posture shown in the figure, but when the posture changes, the posture is changed. It should be changed and interpreted according to the change of.

As shown in the figure, the head 10 includes an elongated substantially cylindrical main body 11 extending linearly and a sphere 12 attached to the tip end (left end in FIG. 1A) of the main body 11. .. The main body 11 is a cylindrical member made of a metal such as stainless steel, having a length of about 180 [mm] and a diameter of about 30 [mm], and having a hollow inside. Further, the sphere 12 is a member that hits a concrete surface, and is a sphere made of a metal such as stainless steel and having a diameter of about 32 [mm], but it does not necessarily have to be a true sphere. As shown in FIG. 2A, it may have a flat surface, and a locking opening may be formed in which one end of the urging member 14 is inserted and locked. Further, the sphere 12 may be made of a metal other than steel such as an aluminum alloy, or may be made of a material other than metal such as wood.

Further, the head 10 further includes an elastic member 13 attached to the tip of the main body 11, an urging member 14 disposed in the cavity of the main body 11, a substrate 15, a sound collecting device 16, and a power supply 17. And a display device 18 attached to the rear end (right end in FIG. 1A) of the main body 11.

The elastic member 13 is, for example, an O-ring having an inner diameter smaller than the diameter of the sphere 12, as shown in FIG. 2 (b), and the urging member 14 is, for example, shown in FIG. 2 (c). It is a coil spring that functions as a tension spring. The right end of the urging member 14 is locked in the main body 11, the left end thereof is locked in the sphere 12, and the sphere 12 is attached to the rear of the main body 11 (right side in FIG. 1A). Force, that is, apply a tensile force to the sphere 12. As a result, the sphere 12 is attached to the tip of the main body 11 in a state of being pressed against the tip of the main body 11 via the elastic member 13.

The substrate 15 is, for example, a circuit board such as a printed circuit board, on which active elements such as integrated circuits (not shown), electronic components such as resistors and passive elements such as capacitors, and electrical components are mounted on the surface or inside thereof. , Various wirings (not shown) are formed.

A sound collecting device 16 is mounted on the substrate 15. The sound collecting device 16 is, for example, a microphone that collects hitting sound, which is a sound generated when a sphere 12 hits a concrete surface. Specifically, it is the sound pressure of the tapping sound, and the sound pressure in the main body 11 which is a cylindrical member is measured. Further, a power supply 17 is connected to the substrate 15. The power supply 17 has, for example, a battery box as shown in FIG. 2D and a battery (not shown) housed in the battery box, and is used on the substrate 15, the sound collecting device 16, the display device 18, and the like. Supply power. Further, a display device 18 attached to the rear end of the main body 11 is connected to the substrate 15. The display device 18 has a display surface made of, for example, an LED, an LCD, or the like, and the display mode of the display surface can be changed into a plurality of types. Specifically, for example, the display color changes to red, yellow, green, blue, white, etc., and the display color is continuously lit or blinks.

Further, it is assumed that the substrate 15 includes, for example, an analyzer and an AD converter having a processing circuit, a recording circuit, a display circuit, and the like as shown in FIGS. 3A to 3C. The analyzer analyzes the sound pressure measured by the sound collecting device 16, detects a defect leading to a cavity or peeling inside the concrete, and displays the detection result on the display device 18.

Further, the head 10 includes a switch (not shown), and by operating the switch to be turned on, electric power is supplied from the power source 17 to each part and each part starts operation. Further, the head portion 10 is provided with an external output terminal (not shown) connected to the substrate 15, and the analysis result, processing data, etc. by the analyzer can be used as data in the form of image data, text data, or the like, if necessary. , The external output terminal can output data to an external device such as a printer or a display (not shown).

Next, the data of the hitting sound measured by hitting the concrete surface will be described in detail.

FIG. 4 is a photograph showing an outline of a sound pressure test on a concrete surface in the present embodiment, FIG. 5 is a diagram showing a sound pressure spectrum in a sound pressure test on a concrete surface in the present embodiment, and FIG. It is a figure which shows the time history data of the sound pressure in the hitting sound test of a concrete surface in a form. In FIGS. 5 and 6, (a) is a diagram when there is no defect, (b) is a diagram when there is an internal cavity, and (c) is a diagram when the winding thickness (thickness of concrete) is insufficient. ..

As mentioned in the section of "Background Technology", in the maintenance of concrete structures such as tunnels, it is necessary to grasp the floating and internal cavities, which are defects that lead to the peeling of concrete pieces, by tapping sound survey. ing. As an alternative to such a manual tapping sound investigation, a method of striking the concrete surface and measuring and analyzing the vibration and striking sound of the concrete surface has been proposed.

In the past, as shown in FIG. 4, the inventors hit a test piece having various defects (concrete wall: thickness 50 [cm]) with an impact hammer, and the surface of the test piece, that is, concrete. The sound pressure of the tapping sound was measured at a position 30 [cm] away from the surface (see, for example, Non-Patent Document 1).
Koji Funakoshi, Satoshi Tsuno, Keisuke Shimamoto, Shinya Ueno, Yuichiro Nishikin: Sound test of concrete test piece assuming tunnel lining, Proceedings of 52nd Ground Engineering Research Presentation, 2017.7

FIG. 5 shows an example of the spectrum of the sound pressure obtained as a result of the measurement. In FIG. 5, the vertical axis represents the Fourier amplitude [Pa], and the horizontal axis represents the frequency [Hz]. As shown in FIG. 5 (b), when an internal cavity (cavity range 50 [cm] × 50 [cm], cover 10 [cm]) is present, a clear peak appears near a frequency of 1000 [Hz]. You can confirm that there is. Further, as shown in FIG. 5 (c), when the winding thickness, that is, the thickness of the concrete is insufficient, the frequency is 1000 as compared with the sound case as shown in FIG. 5 (a). There is a tendency for the sound pressure to increase in the band below [Hz].

Further, FIG. 6 shows an example of sound pressure time history data (0.16 seconds). In FIG. 6, the vertical axis indicates the sound pressure [Pa], and the horizontal axis indicates the time [s] (seconds). As shown in FIG. 6 (b), it can be seen that the time required for attenuation becomes longer when the internal cavity is present.

From these facts, (1) the peak of the sound pressure spectrum is detected, (2) the distribution of the components of 4000 [Hz] or less is grasped for the sound pressure spectrum, and (3) the time history data of the sound pressure is used. It can be said that by grasping the tendency of sound pressure to decrease, it is possible to detect cavities inside concrete and defects that lead to peeling.

Since the measurement as shown in FIG. 4 was carried out in a quiet place, good sound pressure data was obtained, but in the inspection of the actual structure, it was affected by the background noise. There is a concern that good sound pressure data cannot be obtained.

However, in the present embodiment, since the sound pressure in the main body 11 is measured by the sound collecting device 16 arranged in the main body 11 which is a cylindrical member, it is good without being affected by background noise. Sound pressure data can be obtained.

Next, the operation of the inspection hammer device in this embodiment will be described.

FIG. 7 is a diagram showing a sound pressure spectrum in a tapping sound test using the inspection hammer device in the present embodiment, and FIG. 8 shows an example of a display mode of the display device of the inspection hammer device in the present embodiment. Table and FIG. 9 are flowcharts showing the operation of the inspection hammer device according to the present embodiment. In FIG. 7, (a) is a diagram when there is no defect, and (b) is a diagram when there is an internal cavity.

First, when an inspector using the inspection hammer device turns on the switch of the head 10, each part of the head 10 starts to operate. Then, in the state before the concrete surface of the concrete structure is hit, the display mode of the display device 18 is blinking in white (step S1). The inspector can recognize that the inspection hammer device is in a waiting state before hitting, based on the display mode of the display device 18. The display mode of the display device 18 is controlled by the display circuit of the analyzer.

Subsequently, the inspector uses the inspection hammer device to hit the concrete surface of the concrete structure to be inspected, that is, hits the target surface with the hammer (step S2). Specifically, the inspector strikes the concrete surface, which is the target surface, with the sphere 12 attached to the tip of the head 10. As a result, the impact characteristics of the concrete surface are excited to the sphere 12. Then, the vibration of the sphere 12 propagates inside the main body 11 as sound pressure. Then, the time history of the sound pressure is measured by the sound collecting device 16, and the output signal from the measured sound pressure collecting device 16 is converted into a digital signal by the AD converter and input to the analyzer.

Then, the analyzer performs data processing and analyzes the time history data of the measured sound pressure (step S3). When data processing is being performed, the display mode of the display device 18 is blinking in blue.

Data processing is performed by the processing circuit of the analyzer. The processing circuit analyzes the sound pressure attenuation and the frequency distribution of the sound pressure by using the data of the time 0.01 to 0.04 [s] (seconds) in the time history data of the measured sound pressure. By doing so, the soundness of the concrete surface, which is the target surface, is determined.

Specifically, first, in the processing circuit, as processing A, the maximum value of the sound pressure immediately after the impact and the sound pressure after a predetermined time has elapsed after the impact, that is, based on the time history data of the measured sound pressure. , The ratio A1 with the value of the sound pressure at the time when 0.02 [s] has passed after the impact is calculated. This makes it possible to determine the attenuation of the sound pressure.

Subsequently, the processing circuit performs processing B, Fourier transforms the time history data of the sound pressure between 0.04 [s] from the impact, and as shown in FIG. 7, the magnitudes of the frequency and the amplitude spectrum. To get the relationship. In FIG. 7, the vertical axis shows the value normalized by the maximum value of the Fourier amplitude [Pa], and the horizontal axis shows the frequency [Hz].

Then, as shown in FIG. 7, the processing circuit extracts 0 to 4000 [Hz] from the relationship between the frequency and the magnitude of the amplitude spectrum, and divides it into 200 [Hz] × 20 blocks.

Further, the processing circuit acquires the maximum value of the Fourier amplitude [Pa] in each block, and among the 19 blocks excluding the blocks of 0 to 200 [Hz], the frequency at which the Fourier amplitude [Pa] is the maximum. Acquire B1.

Further, in the processing circuit, the value of the Fourier amplitude [Pa] corresponding to the frequency B1 is set to 1, the value of the Fourier amplitude [Pa] in all 20 blocks is normalized, and the normalized Fourier amplitude [Pa] is obtained. The number B2 of blocks including the part of the amplitude spectrum of 0.2 or more is acquired. In the example shown in FIG. 7, in the case of a concrete surface without sound defects as shown in FIG. 7 (a), B2 = 15, and there is an internal cavity as shown in FIG. 7 (b). In the case of the concrete surface to be used, B2 = 2.

Subsequently, the processing circuit performs processing C, and first determines whether or not A1 is larger than the first threshold value of 0.2 (step S3-1). Then, when A1 is larger than the first threshold value, the processing circuit determines that the concrete surface is defective and proceeds to step S3-2, and the display mode of the display device 18 is determined to be continuous lighting in red.

When A1 is equal to or less than the first threshold value, the processing circuit proceeds to step S3-3 to determine whether or not A1 is larger than the second threshold value of 0.05. Then, when A1 is larger than the second threshold value, the processing circuit proceeds to step S3-4, and whether B1 is smaller than 2000, which is the third threshold value, and B2 is smaller than 5, which is the fourth threshold value. Judge whether or not.

Then, when the condition that B1 is smaller than 2000, which is the third threshold value, and B2 is smaller than 5, which is the fourth threshold value, is satisfied, the processing circuit considers that the concrete surface is defective, and steps S3-. Proceeding to 2, the display mode of the display device 18 is determined to be continuous lighting in red. Further, when the condition that B1 is smaller than 2000 which is the third threshold value and B2 is smaller than 5 which is the fourth threshold value is not satisfied, the concrete surface of the processing circuit needs attention. , Step S3-5, and the display mode of the display device 18 is determined to be continuous lighting in yellow.

Further, when it is determined in step S3-3 that A1 is equal to or less than the second threshold value, the processing circuit proceeds to step S3-6, where B1 is smaller than 2000, which is the third threshold value, and B2 is set. It is determined whether or not it is smaller than the fourth threshold value of 5. Then, when the condition that B1 is smaller than 2000 which is the third threshold value and B2 is smaller than 5 which is the fourth threshold value is satisfied, the processing circuit considers that the concrete surface needs attention and steps. Proceeding to S3-5, it is determined that the display mode of the display device 18 is continuous lighting of yellow. Further, when the condition that B1 is smaller than 2000, which is the third threshold value, and B2 is smaller than 5, which is the fourth threshold value, is not satisfied, the processing circuit considers that the concrete surface is sound and steps. Proceeding to S3-7, it is determined that the display mode of the display device 18 is continuous lighting of green.

Finally, the display circuit of the analyzer controls the display mode of the display device 18 according to the determination of the processing circuit in step S3, and the display device 18 continuously lights red, yellow, or green (step S4). ).

Therefore, the inspector can accurately, objectively, and easily grasp the state of the concrete surface of the concrete structure to be inspected by visually recognizing the display mode of the display device 18. Further, since the sound pressure in the main body 11 is measured by the sound collecting device 16 arranged in the cylindrical main body 11 and the state of the concrete surface is determined from this frequency characteristic, background noise can be reduced.

As described above, the inspection hammer device according to the present embodiment includes the head 10. The head portion 10 includes a cylindrical main body 11, a spherical body 12 attached to the tip of the main body 11 via an elastic member 13, a sound collecting device 16 and an analysis device arranged in the main body 11, and a main body. It has a display device 18 attached to the rear end of 11, the sound collecting device 16 measures the sound pressure in the main body 11 generated by the sphere 12 hitting the inspection target, and the analyzer measures the measured sound. The state of the inspection target is determined based on the time history data of the pressure, and the display device 18 changes the display mode according to the state of the inspection target. Further, in the inspection method using the inspection hammer device in the present embodiment, the cylindrical main body 11, the spherical body 12 attached to the tip of the main body 11 via the elastic member 13, and the main body 11 are arranged. This is an inspection method using an inspection hammer device including a head 10 having a sound collecting device 16 and an analyzer and a display device 18 attached to the rear end of the main body 11, and the sphere 12 is struck against the inspection target. The process of hitting the inspection target, the process of measuring the sound pressure in the main body 11 generated by hitting the inspection target by the sound collector 16, and the state of the inspection target based on the time history data of the measured sound pressure. It includes a step of determining by an analyzer and a step of changing the display mode of the display device 18 according to the state of the inspection target.

As a result, the inspection hammer device can accurately, objectively, and easily grasp the state of the concrete structure while being easy to carry.

In addition, the analyzer analyzes the measured sound pressure attenuation or frequency distribution, and determines the soundness as the state to be inspected. Further, the sound pressure attenuation is the ratio of the maximum value of the sound pressure immediately after the impact to the value of the sound pressure after a predetermined time has elapsed after the impact, and when the ratio exceeds the threshold value, the analyzer is said to have poor soundness. to decide. Further, the frequency distribution of the sound pressure is the frequency distribution of the amplitude spectrum in the time history data of the Fourier transformed sound pressure, and if the frequency distribution is not concentrated, the analyzer determines that the soundness is better. Further, the object to be inspected is a concrete surface, and the state of the object to be inspected includes the presence or absence of internal cavities in the concrete and the presence or absence of defects leading to the peeling of the concrete. The display mode includes display colors.

It should be noted that the disclosure herein describes features relating to suitable and exemplary embodiments. Various other embodiments, modifications and modifications within the scope and purpose of the claims attached herein can be naturally conceived by those skilled in the art by reviewing the disclosure of the present specification. be.

The present disclosure can be applied to an inspection hammer device and an inspection method using the same.

10 Head 11 Main body 12 Sphere 13 Elastic member 16 Sound collector 18 Display device

Claims (3)

An inspection hammer device with a head
The head is attached to a cylindrical main body, a sphere attached to the tip of the main body via an elastic member, a sound collecting device and an analyzing device arranged in the main body, and a rear end of the main body. Has a display device
The sound collecting device measures the sound pressure in the main body generated by the sphere hitting the inspection target, and the analyzer measures the measured sound pressure based on the time history data of the measured sound pressure. The attenuation is analyzed, the soundness is determined as the state of the inspection target, and the display device changes the display mode according to the state of the inspection target .
The inspection target is a concrete surface, and the state of the inspection target includes the presence or absence of internal cavities in concrete and the presence or absence of defects leading to concrete peeling.
The sound pressure attenuation is the ratio of the maximum value of the sound pressure immediately after the impact to the value of the sound pressure after a predetermined time has elapsed after the impact, and when the ratio exceeds the threshold value, the analyzer has poor soundness. An inspection hammer device characterized by determining that there is. The inspection hammer device according to claim 1 , wherein the display mode includes display colors. A cylindrical main body, a sphere attached to the tip of the main body via an elastic member, a sound collecting device and an analyzer arranged in the main body, and a display device attached to the rear end of the main body. It is an inspection method using an inspection hammer device equipped with a head having a head.
The process of hitting the sphere against the inspection target and hitting the inspection target,
The process of measuring the sound pressure in the main body generated by hitting the inspection target by the sound collecting device, and
A step of analyzing the attenuation of the measured sound pressure based on the time history data of the measured sound pressure, and determining the soundness as the state to be inspected by the analyzer.
Including a step of changing the display mode of the display device according to the state of the inspection target.
The inspection target is a concrete surface, and the state of the inspection target includes the presence or absence of internal cavities in concrete and the presence or absence of defects leading to concrete peeling.
The sound pressure attenuation is the ratio of the maximum value of the sound pressure immediately after the impact to the value of the sound pressure after a predetermined time has elapsed after the impact, and when the ratio exceeds the threshold value, the analyzer has poor soundness. An inspection method using an inspection hammer device, which is characterized by determining that there is.

Images