JP6496895B2 - Mechanical anchor contact state detection apparatus and method - Google Patents

Description

The present invention simply measures the construction quality of hole-in anchors and mechanical anchors, in which holes are drilled in a base material such as concrete, bedrock, structure, etc., and the male and female screw anchors inserted into the holes are held by frictional force. The present invention relates to an inspection device.
Aged anchors are subject to deterioration such as loosening and corrosion, but can be used for deterioration diagnosis by detecting the contact state with the base material.

Anchor bolts that fix the ceiling plate of the tunnel fall off, fall into a running vehicle, a large number of casualties appear, and a considerable amount of time is closed for road restoration, not only human life but also a great economy Resulting in loss. Improper anchor bolt driving and fixing are expected to impair safety, and there are no methods other than the inspection method by hammering, in which precautions for placing are clearly stated. In such extreme cases, the effectiveness is recognized, but there is no alternative method, so a non-destructive and effective technique is required.
The present invention has been devised in view of the situation as described above, and is effective for the construction quality of newly-placed placement and the existing aging inspection.

JP 2008-268116 A

In railways, the hammering method is used to check for loose mounting of metal parts, cracks on wheels, etc. The hammering method is used to hit the iron with a hammer and detect the presence or absence of cracks in the level of the generated hammering sound. This is an inspection method to be attempted. The principle of operation is that surface vibration is caused by hammering, and if there is a crack, the surface length is increased, so the vibration frequency is lowered and auditory detection is possible. If it is attempted to detect the looseness of the anchor bolts that have been laid, the anchor bolts are buried and the surface is fixed, and surface vibrations are hindered. Also, the anchor bolt has an attached accessory, and since this accessory is exposed in the air, it causes surface vibration, and most of the sound generated by the hitting sound is not attached to the anchor bolt to be inspected. Generated from the appendages.

Regardless of the listening sound, an acceleration sensor or AE sensor is attached to the anchor bolt, the vibration caused by hammering is received, the resonance characteristics are obtained using a technique such as FFT, and the excellent received vibration frequency is compared to compare the anchor bolt Attempts have been made to detect loosening and corrosion.
At first glance, this seems to be a reasonable method, but the vibration frequency generated by the impact is low, that is, the wavelength is long, so resonance cannot be obtained with an anchor bolt of about several tens of centimeters to 1 meter. In most cases, the vibration of the mounting part, the vibration of the exposed part in the air, and the vibration of the accessory are mistaken.

The condition that requires solution is that the anchor bolt to be inspected is attached with an attached structure that easily vibrates at an audible frequency of several hertz to several kilohertz, and that the anchor bolt is not wobbled, such as concrete, bedrock, etc. It is the state which is in the state where it is attached to, and the pulling-out strength of the anchor bolt is deteriorated.

In order to secure an effective area to contact the head of the extended friction part where the anchor bolt is fixed to the hole, the probe shape was optimized.
An ultrasonic transmission / reception device for comparing and analyzing reflected signals obtained from the anchor bolt fixing hole wall surface and the bolt fixing contact surface interface was provided.
When the extended friction part head is buried, a cylindrical or cylindrical divided intermediate medium is provided to ensure acoustic coupling with the probe.

Regarding the mechanical anchor placement failure, the main cause is that due to insufficient adhesion to a fixed support medium such as concrete due to insufficient hammering, the pullout strength is reduced and the necessary function as a mechanical anchor may not be exhibited. After the placement, it is possible to easily determine whether the mechanical anchor is functioning properly or not.
The mechanical quality of the mechanical anchor is the difference between the design pullout strength and the pullout strength after placement, and the smaller the difference, the better.

One of the causes of poor placement is when the hole diameter of a fixed support medium such as concrete is large, there are times when the inner surface of the hole is rough, poor cleaning, etc., the adhesive is used together with the mechanical anchor. Since the contact state between the fixed support and the anchor is detected, it is possible to easily determine whether the anchor function is good or bad.
When installing new equipment, it becomes easy to manage the state of anchor construction, and the existing anchors that have been aged will decay and loosen, but they are used in large quantities because they function as deterioration diagnosis devices. A great economic effect can be expected because it contributes to the safety of attaching accessories such as road noise barriers, tunnel jet fans, and lighting fixtures, and is also non-destructive and simple.
Since the probe is brought into contact with the head of the radially expanded portion, the target bolt is not limited to the male screw and the female screw, and does not depend on the radially extending means.

It is explanatory drawing explaining the before setting by the setting method of a male thread type | mold bolt. It is explanatory drawing explaining after the placement by the placement method of the external thread type bolt. It is explanatory drawing explaining the before setting by the setting method of a female thread type | mold bolt. It is explanatory drawing explaining the after-placement by the placement method of an internal thread type | mold bolt. It is explanatory drawing explaining before driving | running | working by the driving | running method of a pin driving | operation male screw type volt | bolt. It is explanatory drawing explaining after the driving | running | working by the driving | running method of a pin drive-in male screw type volt | bolt. (Example 1) which is the explanatory view which attached the half moon type probe to the sleeve after placement of a male screw type bolt. (Example 2) which is the explanatory view which attached the cylindrical probe to the sleeve after placement of the external thread type bolt. (Example 3) which is the explanatory view which attached the bevel type | mold probe to the sleeve through the tubular intermediate medium after the male thread type | mold bolt was laid. (Example 4) which is the explanatory drawing which attached the half-moon type probe to the sleeve after placement of a female screw type bolt. (Example 5) which is the explanatory view which attached the cylindrical probe to the sleeve after driving of the internal thread type bolt. (Example 6) which is the explanatory drawing which attached the bevel type probe to the sleeve after driving of the internal thread type bolt. (Example 7) which is the explanatory drawing which attached the half-moon type probe to the head after placement of a pin driving male screw type bolt. (Example 8) which is the explanatory drawing which attached the cylindrical probe to the head after the driving of the pin driving male screw type bolt. (Example 9) which is the explanatory drawing which attached the bevel type | mold probe to the head after the driving | running | working of a pin drive-in male screw type | mold bolt. It is explanatory drawing explaining the structure of the half moon type probe. It is explanatory drawing explaining the structure of the cylindrical probe. It is explanatory drawing explaining the structure of a vibrator assembly and a half moon type probe. (Example 10) which is an explanatory sectional view in which a sleeve was buried and raised with an intermediate medium when a male screw type bolt was placed. (Example 11) which is the explanatory drawing which adhered the intermediate medium to the half moon type probe surface. It is the figure explaining the contact state detection apparatus and the probe connection. It is a contact state detection apparatus block diagram. It is a received signal waveform which shows a normal contact state. It is a received signal waveform which shows a bad contact state.

DESCRIPTION OF SYMBOLS 1 Male screw type anchor bolt 2 Sleeve 2a before driving expansion 2 Sleeve 3 after driving expansion 4 Hole of fixed support body, such as concrete bedrock 5 Pin driving pin 6 of male screw type bolt Tubular propagation intermediate medium 7 Angle probe 8 Half moon type Probe 9 Half-moon probe support 9a Tube-shaped probe support 10 Transducer 10a Circular small transducer 10b Square small transducer 11 Cylindrical probe 12 Connection cord, connector, half-moon probe 13 Connection Cord, connector, cylindrical probe 14 Connection cord, connector, oblique probe 15 Contact state detection device

Mechanical anchors are functionally divided into two types of threads, male and female, and there are differences in structure depending on the small diameter and large diameter of the bolt. Therefore, the optimal probe shape for each anchor type and The necessary propagation intermediate medium was devised.

FIG. 22 is a block diagram of the contact state detection device showing the functional operation of the present invention. The transmission pulse is connected to the probe by a transceiver that transmits and receives ultrasonic waves and a detachable connector. The transmission pulse is a spike wave, a rectangle with variable pulse width, or a burst wave with variable fundamental frequency and wave number. However, it is desirable to use a burst wave with high frequency purity.
The 10 vibrators are optimally made of a piezoelectric ceramic, but a magnetostrictive vibrator can also be used.

The received signal obtained from the probe shown in FIG. 22 and the ultrasonic transmission / reception unit shown in FIG. 22 is obtained from the surface of a solid support such as concrete, rock, metal, etc. FIG. 23 is a diagram showing a normal contact state in which a mixed signal of a signal and a multiplexed signal is received, and has a characteristic that the signal strength and tailing in the distance direction are small.

FIG. 24 shows a typical received waveform in a poor contact state. The signal strength and the tailing in the distance direction are significant. The position where the signal strength is maximum corresponds to the tip of the probe and the sleeve or bolt, and the obtained reception signal is the reflection time, but the product of the product of the estimated sound speed divided by 2 corresponds to the distance. Therefore, the length of the sleeve and bolt can be obtained.
The horizontal axis of FIGS. 23 and 24 is a value converted into a distance, the vertical axis is a logarithmic scale, and a small signal is displayed larger than the linear scale.

The determination method is to record the calibration pattern with the anchor bolt of the same shape, the received signal waveform showing the normal contact state in FIG. 23, and the received signal waveform showing the bad contact state in FIG. 24 as a reference signal in the waveform pattern memory. After the probe is brought into contact with the anchor bolt to be measured to obtain the reception pattern, the waveform pattern comparison unit sequentially reads the reference waveform patterns recorded in advance, compares the differences, and obtains a determination output.

The portion surrounded by the wavy line in FIG. 22 can be realized by hardware, but can be easily realized by a computer and software. The content is a software processing of waveform matching, and thus the description is omitted.

FIG. 23 shows a received signal waveform indicating a normal contact state. FIG. 7 shows a typical waveform pattern recorded after placing a male screw-type bolt and contacting a half-moon type probe with a sleeve. Can be used as a good contact state comparison reference signal.
FIG. 24 shows a received signal waveform indicating a bad contact state. A waveform pattern having a large tail in the distance direction of the multiple reflection signal can be used as a bad contact state comparison reference signal.
The waveforms in FIGS. 23 and 24 are not schematic diagrams, but are actually recorded waveforms, and the difference is clear even when visually observed. Similar pass / fail waveform patterns for various bolts recorded in the waveform pattern memory of FIG. 22 are recorded in the memory, and the determination is made by comparing the differences.

The probe illustrated in the embodiment is connected to the ultrasonic transmission / reception device via a connection cord, and displays the received minute reflection signal on the display unit, and is recorded by the recording unit, and reflected by the determination analysis unit. The signal intensity for each distance of the signal is determined, and the contact state between the mechanical anchor and the support is detected. Since the examples are common after the probe, the illustration is omitted.
FIG. 21 is a diagram explaining the contact state detection device and probe connection. The probe shown in the embodiment is connected to the 15-contact state detection device via a connection cord and can be replaced with a connector.
When attaching a probe to a mechanical anchor bolt, if a P wave is applied, a jelly-like propagation medium is applied. If an SH wave is applied, a viscous propagation medium having a shear stress is applied and then the probe is contacted. Is the same as general ultrasonic measurement.

  FIG. 1 shows a state in which a large-diameter male screw type mechanical anchor is inserted into the four driving holes, and the sleeve before two driving expansion is not expanded and is not in contact with the inner surface of the four driving holes.

FIG. 2 shows a state in which the anchor has been placed in FIG. 1. By striking the expansion bolt sleeve 2 in FIG. 1 with a cylindrical jig having the same diameter, 3 collides with the hook, and the tip of the sleeve is It expands in the radial direction at the base of the slit, deforms into a sleeve shape after being driven and expanded by 2a, and comes into contact with the inner surface of the four driving holes.
If this contact state is strong, the anchor function is good, and the pull-out strength of the single male thread type anchor bolt satisfies the design value.

FIG. 7 is an explanatory diagram in which the half-moon type probe of the first embodiment is mounted on a sleeve. It is connected to the ultrasonic transmission / reception apparatus by an 8 crescent probe and a connection cable (not shown). The ultrasonic wave reflected by the lower end of the sleeve after the 2a driving expansion repeats multiple reflections and exhibits the characteristics of the received signal reflecting the contact state between the anchor and the support. FIG. 23 is a typical received signal waveform showing the normal contact state. FIG. 24 shows a received signal waveform indicating a bad contact, and the multiple reflection signal level increases as the contact between the hole of the 4 fixed support and the sleeve after the 2a driving expansion decreases.

FIG. 8 is an explanatory diagram in which the cylindrical probe of the second embodiment is mounted on a sleeve. Reference numeral 11 denotes a cylindrical probe, and the structure thereof is as shown in FIG. 17. Since the contact area between the 10 transducers and the sleeve 2a after being expanded is large, there is an advantage that transmission / reception can be performed with high sensitivity. The contact state of the entire circumference of the sleeve can be evaluated. If the contact surface of the 2a sleeve is scratched or rough, contact with the cylindrical probe 11 is obstructed, and the contact area is enlarged. There is also the disadvantage of hindering degradation and stability.

FIG. 9 is an explanatory diagram in which a 7-bevel probe is mounted on a sleeve via a 6-pipe propagation intermediate medium after the male screw bolt is placed. In the first and second embodiments, the signal wave transmitted and received from the probe is a P wave. In the third embodiment, an SV wave and an SH wave can be used.

FIG. 3 is an explanatory diagram explaining the pre-casting method by the female screw-type bolt driving method. 2 By hitting the upper end of the sleeve with a flat hammer, 3 collides with the hook, the sleeve tip expands in the radial direction at the base of the slit, deforms into the sleeve shape after the 2a drive expansion, Adheres to and sticks to.
Although the place where the screw is cut in the sleeve inner surface is different from the first embodiment, the sleeve expansion structure is the same.
FIG. 10 is an explanatory diagram in which an 8 crescent probe is mounted on the 2a sleeve after the internal thread type bolt is placed. The signal waveform obtained is the same as that of the first embodiment, and the description is omitted.

FIG. 11 is an explanatory view in which an 11-cylindrical probe is attached to the sleeve after the female screw-type bolt is placed. Since this is the same as the male screw bolt of Example 2, the explanation is omitted.

FIG. 12 is an explanatory view in which the bevel type probe is mounted on the sleeve after the female screw type bolt is placed. The structure is acoustically coupled to the sleeve head via six tubular propagation intermediate media, and SV waves and SH waves can be used.

FIG. 13 is an explanatory view in which a half-moon type probe is mounted on the head after the pin driving male screw type bolt is driven. The curvature of the half moon, which avoids the pin of the 5-pin driven male screw type bolt and is acoustically coupled with the head of the 1 male screw type anchor bolt, is determined in consideration of the head of the 5 pin and the male screw type anchor bolt head.

FIG. 14 is an explanatory view in which a cylindrical probe is mounted on the head after the pin driving male screw type bolt is driven. The 11-cylindrical probe is in contact with the entire surface of the head of the male screw type anchor bolt and avoids the pin of the male screw type bolt.

FIG. 15 is an explanatory view in which a bevel type probe is mounted on the head after the pin driving male screw type bolt is placed. Since the 7-bevel probe can be in direct contact with the head of one male threaded anchor bolt, no intermediate propagation medium is required.

FIG. 16 is a perspective view illustrating the structure of the half-moon probe, and 10 transducers are bonded to the support of the nine-half moon probe via a backing material. A protective film is bonded to the surface of the vibrator.

FIG. 17 is a perspective view illustrating the structure of a cylindrical probe, in which a 10 hollow vibrator is bonded to a support of a 9a tube-shaped probe via a backing material, and a protective film is provided on the vibrator surface. It is glued.

FIG. 18 is a plan view seen from the transducer surface explaining the structure of the transducer assembly meniscus probe. The half-moon probe is not only a single half-moon type but also a 10a circular small vibration shown in FIG. It is also possible to assemble with a small 10b square small vibrator and connect each vibrator in parallel with a thin electric wire, and it is also possible to assemble in a continuous circle.

FIG. 19 is an explanatory cross-sectional view in which a 2a sleeve is buried in a hole of a fixed support body such as a 4 concrete bedrock and raised with 6 intermediate media when a male screw type bolt is placed. In this state, since the probe cannot contact the 2a sleeve head, 6 tubular propagation intermediate media are inserted, raised from the hole of the fixed support such as 4 concrete bedrock, and contacted with the probe. I made it possible. The material of the intermediate propagation medium is preferably an acrylic resin or polystyrene resin having a small acoustic attenuation.

6 The intermediate propagation medium has been described as a tube, but as a partially divided type in the radial direction of the pipe, it is possible to use a half-moon type probe as shown in FIG. realizable.

FIG. 20 is an explanatory diagram in which an intermediate propagation medium is bonded to the surface of the half-moon type probe. 7 If the intermediate medium is created longer than the anticipated depression length, it is possible to save the trouble of preparing a medium with a different length of the 6 intermediate propagation medium. However, since the intermediate propagation medium attenuates the sound, the sensitivity is lowered. There are disadvantages to invite.
Although not shown, a cylindrical intermediate propagation medium can also be adhered to the surface of the cylindrical probe in FIG. 17. The intermediate propagation medium is preferably made of a material having a small acoustic attenuation such as acrylic resin or polystyrene resin.

 TECHNICAL FIELD The present invention relates to a method for performing placement quality control of post-installed mechanical anchors related to the civil engineering and construction fields, and simple determination of deterioration of existing anchors. Other possibilities are expected to be widely used.

Claims (3)

In a mechanical structure anchor having a radially extending portion, ultrasonic transmission / reception in which an electroacoustic transducer is attached to an aerial protrusion continuous to the radially expanded portion of the anchor and connected to the electroacoustic transducer via a connection cable Using a device, a waveform pattern memory for recording an electric signal waveform pattern obtained from the radially expanded contact portion and the fixed support wall contact interface, and a waveform matching software process for comparing and comparing with a pre-recorded pass / fail waveform pattern A detection device comprising a computer comparison unit for detecting a contact state between a mechanical structure anchor and a fixed support. Using the detection device of claim 1,
Electroacoustic transducer means having a half-moon-shaped or hollow circular vibrating surface in contact with the aerial protrusion continuous with the radially extending portion of the anchor in the aerial protrusion is transmitted in a jelly-like manner to the anchor aerial protrusion. A measurement method in which a medium or a viscous propagation medium having a shear stress is applied and contacted to detect a contact state between the radially expanded portion of the anchor and a fixed support wall surface . The measuring method according to claim 2, wherein a cylindrical intermediate propagation medium or an intermediate propagation medium of a divided cylinder is provided between the aerial protrusion continuous to the radially extending portion of the anchor and the electroacoustic conversion means to be contact-mounted. .

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