JP5500887B2 - Anchor bolt shape exploration method and apparatus - Google Patents

Description

  The present invention relates to an anchor bolt shape search method and an apparatus for searching for an anchor bolt shape partially embedded in a concrete structure.

The number of concrete structures that have been constructed in the past, such as highway bridges and Shinkansen bridges, is enormous.
In connection with the breakage and collapse of concrete structures caused by several recent large earthquakes, the seismic reinforcement and maintenance of these concrete structures has become a socially urgent situation.

  Under such circumstances, as one of the necessary items for conducting a wide range of maintenance work for structures, in the case of existing concrete bridges, anchors as structural elements necessary for tight connection between beam girders and abutments A non-destructive inspection of whether or not the bolt is structurally appropriate is required.

A conventional anchor bolt shape exploration method and apparatus are as follows.
That is, as shown in FIG. 32, an ultrasonic device having a shared probe for transmitting and receiving a narrowband ultrasonic wave (narrowband wave) having a center frequency of about 2.5 MHz is embedded in concrete 80. The anchor bolt 81 is being explored. In FIG. 32, reference numeral 82 denotes a support fitting such as an iron plate.

The waveforms of the input wave and the received wave shown in FIG. 32 are shown in FIG.
As shown in FIG. 33A, the spectrum of the input wave is a narrow-band wave having a center frequency of around 2.5 MHz, and is a pulse wave of about one wave. The received wave is a narrow-band spectrum wave corresponding to the input spectrum (see the received wave spectrum in FIG. 5B). As shown in the left diagram of FIG. 33 (b), the time series wave received wave is a wave pulsed wave is generated for each equal time t _h.

The meaning of this pulse-like continuous wave will be described with reference to FIG.
The upper part of FIG. 34 shows a state where the reflected wave from the tip (lower end) of the anchor bolt 81 embedded in the concrete 80 is repeatedly reflected when ultrasonic waves are input from the end (upper end) of the anchor bolt 81. Show.
The lower part of FIG. 34, the overlapping reflected wave for each time t _h, it shows the situation occurring in a pulsed manner.

上記［数３］からアンカボルト長ｌ_Ｔを求めることも可能となる。 Here, the time t _h is the reflection time in the longitudinal direction of the anchor bolt 81, that is, the time μsec when the reflected wave occurs, the sound speed is V _p (mm / μsec), and the length l _T (mm of the anchor bolt 81 is mm. ), It can be obtained by the following [Equation 3].

The anchor bolt length l _T can also be obtained from the above [Equation 3].

但し、Ｋは係数
これにより、既設コンクリート構造物でのアンカボルト長が従来技術に基づいて超音波装置にて探査されている。 On the other hand, when the anchor bolt 81 is embedded in the concrete 80, the required structural standard for construction is the definition of the diameter Φ _A of the anchor bolt 81 and the length l _A embedded in the concrete 80, and the diameter Φ The relationship between _A and the length l _A can be expressed by the following [Equation 4].

Where K is a coefficient
Thereby, the anchor bolt length in the existing concrete structure is searched by the ultrasonic device based on the prior art.

  If the anchor bolts 81 are all straight and normal as shown in FIG. 35 (a), there is no problem in particular, but in a concrete structure 20-30 years ago, structural factors and Due to some factors, there is a shape of the anchor bolt 81 as shown in FIGS. 35B, 35C, and 35D, which becomes a problem.

なお、一般的にＶ_ｐ＝５９００ｍ／ｓｅｃである。
しかしながら、図３５（ｂ）に示す溶接継手８３を有するアンカボルト８１の場合には、溶接継手８３を除くアンカボルト８１のみの長さｌ_１が求められ、図３５（ｃ）に示す湾曲アンカボルト８１、同図（ｄ）に示す先端先鋭アンカボルト８１の場合には、図３４に示す重複反射の出現のみならず、１回目の反射波の起生も得られない。 The anchor bolt 81 shown in FIG. 35 (b) has a welded joint 83 connected to the weld surface, and the anchor bolt 81 shown in FIG. 35 (c) is curved as shown in FIG. 35 (d). The anchor bolt 81 shown has a sharply pointed tip (lower end).
In the case of the normal straight anchor bolt 81 shown in FIG. 35A, the overlapping reflected wave shown in FIG. 34 can be obtained. Therefore, the anchor bolt length l _T (total length) is obtained by the following [Equation 5]. be able to.

In general, V _p = 5900 m / sec.
However, the, is required length l ₁ of only anchor bolt 81 with the exception of the welded joint 83 when the anchor bolt 81 having a welded joint 83 shown in FIG. 35 (b), the curved anchor bolt shown in FIG. 35 (c) 81, in the case of the tip sharp anchor bolt 81 shown in FIG. 4D, not only the occurrence of the double reflection shown in FIG. 34 but also the first reflected wave is not generated.

This is because the input wave by the probe of the conventional ultrasonic device is a narrow-band wave of about 2.5 MHz, and the frequency is relatively high at 2.5 MHz, so that the ultrasonic wave is transmitted into the anchor bolt. In particular, in the case of the curved anchor bolt 81 and the sharp tip anchor bolt 81, it is assumed that the attenuation is doubled.
Furthermore, as shown in FIG. 36, there are many cases where the longitudinal side surface of the anchor bolt 81 in contact with the concrete 80 is corroded 84 as shown in FIG. To do.

  Even if the corrosion 84 does not affect the safety of the structure, the ultrasonic transmission behavior in the longitudinal direction of the anchor bolt 81 greatly fluctuates, resulting in the overlap shown in FIG. In some cases, the reflected wave cannot be generated.

The right side of FIG. 36 schematically shows the received wave when the occurrence of the overlapping reflected wave cannot be obtained.
In Figure 36, when the value of Okoshisei time of the reflected wave of the anchor bolt length first bears on the total length l _T of the anchor bolt 81 and t _h, 1/2 degree of the wave t _h occurring in the presence of corrosion 84 Therefore, the so-called mixed wave in which these two waves are mixed makes it difficult to distinguish the wave generated due to the presence of the corrosion 84 from the original reflected wave, and the occurrence of overlapping reflection with respect to the anchor bolt length. The raw material cannot be secured, and the anchor bolt 81 cannot be analyzed and measured.

  Such inability to analyze also occurs in the linear anchor bolt 81 shown in the left diagram of FIG. 36, so that the anchor bolt 81 with a welded joint and the curved anchor bolt 81 shown in FIGS. In the case where the tip sharp anchor bolt 81 is corroded, analysis and measurement are completely impossible.

  By the way, Patent Document 1 discloses an ultrasonic detection method and apparatus for detecting an internal structure of a detected object by inputting ultrasonic waves to a concrete material as a detected object. Because of the use of .5 MHz narrow-band ultrasonic waves, the same problem as described above occurs even if the one disclosed in Patent Document 1 is applied to the shape search for anchor bolts.

Japanese Patent No. 4050470

Therefore, the present invention transmits broadband ultrasonic waves from the end face of the anchor bolt, receives wideband ultrasonic waves from the same end face, obtains a wideband received wave spectrum by Fourier transform from the received wideband received wave, the center frequency by extracting a narrowband spectrum to f _K, the time-series wave narrowband spectrum at the inverse Fourier transform, sequentially determined in the background of gradually decreasing the central frequency f _K, the time-sequential by obtaining the Okoshisei of the reflected waves from the anchor bolt tip from the waves, even if there is corrosion longitudinal sides of the anchor bolt, gradually reducing the f _K, the degree and shape of the corrosion progress of the anchor bolt (curved, Since the time-series wave is obtained based on a relatively low frequency that is not easily affected by the attenuation during the ultrasonic transmission process due to the sharp tip, the occurrence of the reflected wave can be ensured. , And an object thereof is to provide a shape exploration methods and apparatus of the anchor bolt can contribute to shape exploration anchor bolt.

An anchor bolt shape exploration device according to the present invention includes a probe that transmits and receives an ultrasonic wave, or a probe that shares the transmission and reception of an ultrasonic wave, a part of which is provided in a concrete structure. An anchor bolt shape exploration device for exploring the shape of an embedded anchor bolt, transmitting broadband ultrasonic waves from the end face of the anchor bolt, receiving broadband ultrasonic waves at the same end face, and Fourier from the received wideband received wave a first arithmetic function for determining the broadband receiving wave spectrum at converting the center frequency from the wideband received wave spectrum to extract the narrowband spectrum to f _K, the time-series wave narrowband spectrum at the inverse Fourier transform, a second calculation function found sequentially in the background of gradually decreasing the central frequency f _K, the computing means having a provided, reflections from anchor bolt tip from the time-sequential wave And requests the Okoshisei.

The above-described transmitted and received broadband ultrasonic waves are preferably broadband component waves having components in all frequency bands of 0 to 5 MHz.
Further, the above-described center frequency can be set to an arbitrary frequency with f _K = 2.5 MHz, f _K = 1.25 MHz, and f _K = 0.99 MHz or lower, where f _K = 2.5 MHz.

According to the above configuration, the first calculation function of the calculation means obtains a wideband received wave spectrum from the received wideband received wave by Fourier transform, and the second calculation function of the calculation means calculates the center frequency f from the wideband received wave spectrum. extracting a narrowband spectrum with a _K, the time-series wave narrowband spectrum at the inverse Fourier transform, so found sequentially in the background of gradually decreasing the central frequency f _K, anchor from the time-sequential wave The occurrence of the reflected wave from the tip of the bolt can be obtained.

Therefore, even if there is corrosion longitudinal sides of the anchor bolt, the center frequency f _K was gradually reduced, the ultrasonic transmission susceptible relative influence of the attenuation in the background by the degree and shape of the corrosion progress of the anchor bolt Since the time-series wave is obtained based on a low frequency, the occurrence of the reflected wave can be ensured and the shape of the anchor bolt can be investigated.

According to another embodiment of the present invention, by multiplying a function generating means for generating a time-series function based on Okoshisei time t _h of the reflected waves from the tip of the anchor bolt, the time-series function to the broadband receiving waves, Spectral calculation means for obtaining the spectrum of the reflected wave related to the anchor bolt length by Fourier transform is determined. When the spectrum stands in a band of a predetermined frequency or higher, it is determined as a straight anchor bolt. Judgment.
For example, the predetermined frequency may be set to 0.45 MHz or 0.5357 MHz.

According to the above structure, function creating means creates a time-series function (TGC function) based on Okoshisei time t _h of the reflected waves from the tip of the anchor bolt, the spectrum calculating means, time to the broadband receiving wave Since the spectrum of the reflected wave related to the anchor bolt length is obtained by Fourier transformation by multiplying by the series function, when the spectrum stands in the band above the predetermined frequency, it is judged as a straight anchor bolt, and when it does not stand Can be determined as a curved anchor bolt.
As a result, it is possible to determine whether the anchor bolt to be measured (search target) is a straight anchor bolt or a curved anchor bolt.

により計算する計算手段と、上記広帯域受信波スペクトルにおいて、最低周波数帯域の起生スペクトルをＡとし、次に低い周波数帯域の起生スペクトルをＢとした時、起生スペクトルＡ、Ｂを含む周波数帯域のスペクトル群を抽出し、フーリエ逆変換にて上記スペクトル群に対応する時系列波を求める時系列演算手段と、上記横波Ｍ１，Ｍ２の起生時刻ｔ_Ｍ１，ｔ_Ｍ２の値に基づいて所定の時系列関数をＡ、Ｂスペクトル群に対応する時系列波に乗ずることで、この時刻ｔ_Ｍ１，ｔ_Ｍ２より生ずる横波Ｍ１，Ｍ２を抽出し、この抽出波のスペクトルをフーリエ変換で求めるスペクトル演算手段とを備え、Ｍ１，Ｍ２のスペクトルの双方で、ＡおよびＢ領域のスペクトルのうち、Ｂ領域のスペクトルのみが消滅する時、アンカボルトが一本物で溶接継手なしと判断する一方、Ｍ１のスペクトルにおいて、ＡおよびＢ領域のスペクトルのうち、Ｂ領域スペクトルのみが消滅し、かつＭ２のスペクトルにおいて、ＡおよびＢ領域のスペクトルのうち、Ａ領域スペクトルのみが消滅、または大きく減衰する時、アンカボルトが溶接継手ありと判断するものである。
上述の最低周波数帯域（Ａ領域）は３７ｋＨｚ付近の２５．３ｋＨｚ〜４９．２ｋＨｚに設定してもよく、次に低い周波数帯域（Ｂ領域）は７０ｋＨｚ付近の６０．９ｋＨｚ〜９１．９ｋＨｚに設定してもよい。 In one embodiment of the invention, the Okoshisei time of the reflected wave from the anchor bolt tip and t _h, the sound velocity ratio between the transverse and longitudinal waves for transmitting the anchor bolt longitudinal direction epsilon _1, the anchor bolt joints Occurrence time (t _M1 , t _M2 ) of the transverse wave M1 generated in the section and the longitudinal transverse wave M2 generated when ultrasonic waves are input from the end face of the anchor bolt

In the wideband received wave spectrum, the frequency spectrum including the occurrence spectra A and B, where A is the occurrence spectrum in the lowest frequency band and B is the occurrence spectrum in the next lower frequency band. And a time series calculation means for obtaining a time series wave corresponding to the spectrum group by inverse Fourier transform, and a predetermined time based on the values of the occurrence times t _M1 and t _M2 of the transverse waves M1 and M2. Spectral calculation means for extracting the transverse waves M1 and M2 generated from the times t _M1 and t _M2 by multiplying the time series function corresponding to the A and B spectrum groups by the time series function and obtaining the spectrum of the extracted waves by Fourier transform When both the spectrum of M1 and M2 of the spectrum of the A and B regions, only the spectrum of the B region disappears, there is one anchor bolt. On the other hand, in the M1 spectrum, only the B region spectrum disappears out of the A and B region spectra, and in the M2 spectrum, only the A region spectrum out of the A and B region spectra is determined. When is disappeared or greatly attenuated, the anchor bolt is judged to have a welded joint.
The lowest frequency band (A region) described above may be set to 25.3 kHz to 49.2 kHz near 37 kHz, and the next lower frequency band (B region) may be set to 60.9 kHz to 91.9 kHz near 70 kHz. May be.

According to the above configuration, the calculating means calculates the occurrence times t _M1 and t _M2 of the transverse waves M1 and M2 based on the [Equation 1] and [Equation 2], and the time series wave calculating means A spectrum group in the frequency band including the spectra A and B is extracted, a time series wave corresponding to the spectrum group is obtained by inverse Fourier transform, and the spectrum calculation means generates the occurrence times t _M1 and t _M2 of the transverse waves M1 and _M2. of a predetermined time series function based on the value that multiplies the time series waves corresponding a, the B spectrum group, to extract the shear wave M1, M2 arising from the time t _M1, t _M2, the spectrum of the extracted wave ( M1 wave spectrum and M2 wave spectrum) are obtained by Fourier transform. Therefore, if only the spectrum of region B disappears in both M1 and M2 spectra, it is determined that the anchor bolt is a single one and there is no welded joint. On the other hand, if only the B region spectrum disappears in the M1 spectrum and only the A region spectrum disappears or greatly declines in the M2 spectrum, it is determined that the anchor bolt has a welded joint. Can do.
As a result, it is possible to determine whether the anchor bolt to be measured (exploration target) is a single anchor bolt without a welded joint or an anchor bolt with a welded joint.

The anchor bolt shape exploration method according to the present invention includes a probe that transmits and receives ultrasonic waves, or a probe that shares transmission and reception of ultrasonic waves, and a part of the concrete structure is provided with the probe. An anchor bolt shape exploration method for exploring the shape of an embedded anchor bolt, wherein a first step of transmitting a broadband ultrasonic wave from the end face of the anchor bolt and receiving a broadband ultrasonic wave at the same end face is received. a second step of obtaining a broadband receiving wave spectrum at the Fourier transform from the wideband received wave, extracts a narrowband spectrum with a center frequency f _K from the broadband receiving wave spectrum when the narrowband spectrum at the inverse Fourier transform series wave, a third step of sequentially obtaining in the background of gradually decreasing the central frequency f _K, from the time series waves, the Okoshisei of the reflected waves from the anchor bolt tip determined A fourth step that is those with.

The above-described transmitted and received broadband ultrasonic waves are preferably broadband component waves having components in all frequency bands of 0 to 5 MHz.
Further, the above-described center frequency can be set to an arbitrary frequency with f _K = 2.5 MHz, f _K = 1.25 MHz, and f _K = 0.99 MHz or lower, where f _K = 2.5 MHz.

According to the said structure, a broadband ultrasonic wave is transmitted from an anchor volt | bolt end surface at a 1st process, and a broadband ultrasonic wave is received by the same end surface. In the next second step, a broadband received wave spectrum is obtained by Fourier transform from the received broadband received wave. In the next third step, the center frequency from the broadband receiving wave spectrum to extract the narrowband spectrum to f _K, the time-series wave narrowband spectrum at the inverse Fourier transform, the center frequency f _K gradually It asks sequentially in the process of making it smaller. In the next fourth step, the occurrence of the reflected wave from the tip of the anchor bolt is obtained from the time series wave.
Therefore, even if there is corrosion longitudinal sides of the anchor bolt, the center frequency f _K was gradually reduced, the ultrasonic transmission susceptible relative influence of the attenuation in the background by the degree and shape of the corrosion progress of the anchor bolt Since the time-series wave is obtained based on a low frequency, the occurrence of the reflected wave can be ensured and the shape of the anchor bolt can be investigated.

According to this invention, broadband ultrasonic waves are transmitted from the end face of the anchor bolt, broadband ultrasonic waves are received at the same end face, a broadband received wave spectrum is obtained from the received broadband received wave by Fourier transform, and the broadband received wave spectrum is obtained. the center frequency by extracting a narrowband spectrum to f _K, the time-series wave narrowband spectrum at the inverse Fourier transform, sequentially determined in the background of gradually decreasing the central frequency f _K, the time-sequential since it is configured to determine a Okoshisei of the reflected waves from the anchor bolt tip from the waves, even if there is corrosion longitudinal sides of the anchor bolt, gradually reduce the center frequency f _K, the degree of corrosion progress of the anchor bolt The time series wave is obtained based on a relatively low frequency that is not easily affected by attenuation during the ultrasonic transmission process due to the shape and shape (curvature, sharp tip). Can be coercive, there is an effect that can contribute to the shape exploration anchor bolt.

The block diagram of the shape search apparatus used for the shape search method of the anchor bolt of this invention Illustration of the outgoing probe Explanatory diagram of step-type voltage generator for transmitter Illustration of the receiving probe Illustration of broadband ultrasound (A) is explanatory drawing in the case of using a transmission probe and a receiving probe, (b) is explanatory drawing in the case of using a probe that shares transmission and reception. Process drawing of 1st Embodiment Illustration of broadband input wave spectrum and broadband received wave spectrum used for shape exploration Illustration of spectrum extraction function (A) is a time series wave of a conventional 2.5 MHz narrowband spectrum, (b) is a time series wave of a 1.25 MHz narrowband spectrum of this embodiment, and (c) is a 0.99 MHz narrowband spectrum of this embodiment. Waveform diagram showing the time series of (A) is explanatory drawing of a straight anchor bolt, (b)-(d) is explanatory drawing of a curved anchor bolt. Received waveform chart by anchor bolt shape exploration device of comparative example (A) is explanatory drawing which shows transmission of anchor bolt longitudinal direction of 2.5 MHz ultrasonic wave, (b) is explanatory drawing which shows transmission of anchor bolt longitudinal direction of 1.25 MHz ultrasonic wave. Process drawing of 2nd Embodiment Waveform diagram when obtaining time series wave by inverse Fourier transform Waveform diagram when obtaining time series wave by inverse Fourier transform Waveform diagram when obtaining the spectrum of reflected wave by Fourier transform (A) is explanatory drawing of a single anchor bolt, (b) is explanatory drawing of an anchor bolt with a welded joint Process drawing of 3rd Embodiment Explanatory drawing showing the difference in the occurrence of reflected waves between a single anchor bolt and an anchor bolt with joint Waveform diagram when obtaining time series wave by inverse Fourier transform (A) is explanatory drawing which shows generation | occurrence | production of the longitudinal wave P, (b) is explanatory drawing which shows generation | occurrence | production of the transverse wave M1, (c) is explanatory drawing which shows generation | occurrence | production of the transverse wave M2. Waveform diagram when obtaining the spectrum of A2 and B region of M2 wave by Fourier transform Waveform diagram when obtaining spectrum of A1 and B region of M1 wave by Fourier transform Process drawing of 4th Embodiment Waveform diagram when obtaining broadband received wave spectrum by Fourier transform Waveform diagram when obtaining time series wave by inverse Fourier transform Waveform diagram when obtaining spectrum of A and B regions of a single anchor bolt by Fourier transform Waveform diagram when obtaining the A and B spectrums of anchor bolts with joints by Fourier transform Waveform diagram when obtaining spectrum of A and B regions of a single anchor bolt by Fourier transform Waveform diagram when obtaining the A and B spectrums of anchor bolts with joints by Fourier transform Explanatory drawing showing conventional anchor bolt shape exploration (A) is a waveform diagram showing a conventional 2.5 MHz narrowband input wave, (b) is a waveform diagram showing a conventional 2.5 MHz narrowband received wave. Explanatory drawing showing the received wave shape and the overlapping reflection in the anchor bolt longitudinal direction (A) is explanatory drawing of a normal straight anchor bolt, (b) is explanatory drawing of an anchor bolt with a joint, (c) is explanatory drawing of a curved anchor bolt, (d) is explanatory drawing of a tip sharp anchor bolt Explanatory drawing showing the state of the received wave when there is corrosion on the anchor bolt surface

[Embodiment 1]
An embodiment of the present invention will be described in detail with reference to the drawings.
The drawing shows an anchor bolt shape search method and apparatus. First, the configuration of the anchor bolt shape search apparatus will be described with reference to FIG.

A transmitting probe 31 and a receiving probe 32 that are arranged in contact with the surface (an end face of the anchor bolt) of the anchor bolt 30 as a detection target are provided.
The transmission probe 31 transmits broadband ultrasonic waves (for example, a broadband component wave having components in all frequency bands of 0 to 5 MHz), and the reception probe 32 described above transmits broadband ultrasonic waves of 0 to 5 MHz. A sound wave is received.

  The transmission probe 31 is supplied with a current from the current supply circuit 33 of the ultrasonic transmission device, and an ultrasonic wave is transmitted from the transmission probe 31 and enters the anchor bolt 30.

The ultrasonic signal received by the reception probe 32 is input to the analysis device 34 and analyzed.
In this analysis device 34, after the reception signal of the reception probe 32 is amplified by the amplification circuit 35, the signal filtered by the filter circuit 36 is converted into a digital signal by the AD conversion circuit 37 (analog / digital conversion circuit). The converted data is input to the CPU 40 via the gate array 38.

  The hard disk 39 stores analysis processing application software and time series data processed by the CPU 40. Here, the CPU 40 described above is control means (processing unit) that performs Fourier transform and inverse Fourier transform.

  The analysis result described above is also input to the display device 41 and displayed. The display device 41 is display means for visually displaying various waveforms as shown in FIG.

  In addition, necessary information is input to the CPU 40 from an input device 42 such as a keyboard as input means. The memory 43 is used for temporarily storing data when the CPU 40 calculates. Further, a control signal is output from the CPU 40 to the control circuit 44, and the control circuit 44 outputs an operation command signal to the amplification circuit 35, the filter circuit 36, the AD conversion circuit 37, the gate array 38 and the current supply circuit 33.

  The current supply circuit 33 is connected to the transmission probe 31 via a coaxial cable 45. As shown in FIG. 2, the transmission probe 31 includes a stepped voltage generator 46 and a vibrator 47 formed as a base. And built-in.

  As shown in FIG. 3, the step type voltage generator 46 includes a step voltage driving circuit 461 and a step voltage generating circuit 462. The step function type voltage generated by the step voltage driving circuit 461 is supplied to the vibrator 47. Apply to.

Each time a broadband ultrasonic wave is input to the anchor bolt 30, a reception wave is obtained by the reception probe 32.
This received wave is sent to the amplifier circuit 35 of the analyzer 34 as voltage fluctuation data via the coaxial cable 49. The time variation data sent to the amplifier circuit 35 reaches the AD conversion circuit 37 via the filter circuit 36, the analog amount of this voltage is converted into a digital amount by the AD conversion circuit 37, and the CPU 40 passes through the gate array 38. And the time history of the voltage digital value is displayed on the display device 41.

  Commands for amplification or reduction of voltage and low-pass / high-pass filter processing are transmitted to the CPU 40 automatically or by an instruction from the outside using the input device 42 such as a keyboard. The CPU 40 receives the amplification circuit via the control circuit 44. 35 and the filter circuit 36 are controlled.

  As shown in FIG. 4, the reception probe 32 includes a gradually decreasing high-pass filter circuit 50, an amplifier circuit 51, and a vibrator 52.

  The current supply circuit 33 is controlled by the control circuit 44 and operates at predetermined time intervals.

  The vibrator 52 (see FIG. 4) built in the receiving probe 32 excites vibration with the change in sound pressure of the anchor bolt 30 every time broadband ultrasonic waves are input. The time change of the voltage generated in the vibrator 52 by this vibration excitation is subjected to primary processing by the filter circuit 50 and the amplifier circuit 51 in the reception probe 32.

  When the control of the amplifier circuit 35 and the filter circuit 36 in FIG. 1 is completed, the control circuit 44 operates in response to an instruction from the CPU 40, and instructs the gate array 38 to perform addition processing of the received wave.

  The gate array 38 adds the time history digital quantity relating to the voltage obtained by the AD conversion circuit 37 to the designated number of times each time the time history is obtained. Then, an addition average time history is created under the control of the CPU 40, and the time history is displayed on the display device 41 in real time.

  The filter circuits 50 and 36 and the amplifier circuits 51 and 35 are incorporated in both the reception probe 32 and the analysis device 34, respectively. The high-pass filter circuit 50 and the amplifier circuit 51 built in the reception probe 32 perform primary processing on the received wave. The amplifier circuit 35 and the filter circuit 36 built in the analysis device 34 are: The received wave subjected to the primary processing is finely adjusted under the control of the CPU 40. Since this fine adjustment is necessary for enhancing the function of the apparatus, the amplifier circuit 35 and the filter circuit 36 may be omitted.

  Next, with reference to FIG. 5, the difference between the ultrasonic wave by the pulse type voltage load and the ultrasonic wave by the step function type voltage load will be described.

FIG. 5A shows a spectrum when a pulse voltage (30 to 500 V) is applied to the vibrator. In this case, the resonance frequency in the thickness direction of the vibrator is set as the center frequency as shown in FIG. A transmitted ultrasonic wave having a relatively narrow band spectrum is obtained (corresponding to the narrow band frequency of the prior art).
FIG. 5B shows a spectrum when a step function voltage (30 to 500 V) is applied to the transducer 47 in the transmission probe 31. In this case, the resonance frequency is of course as shown in FIG. That is, a spectrum having a frequency lower than this is also excited, and the broadband ultrasonic wave of this embodiment means the ultrasonic wave according to FIG. 5B.

  FIG. 6 shows an arrangement structure of the probe when searching for the shape of the anchor bolt 30 partially embedded in the concrete 20, and as shown in FIG. 6A, the end face 30a of the anchor bolt 30 is shown. A shape probe may be performed by arranging a transmitting probe 31 for transmitting a broadband ultrasonic wave of 0 to 5 MHz and a receiving probe 32 for receiving a broadband ultrasonic wave of 0 to 5 MHz in FIG. As shown in FIG. 6 (b), a probe 21 that shares transmission and reception of broadband ultrasonic waves of 0 to 5 MHz may be arranged on the end face 30a of the anchor bolt 30 to perform shape exploration.

  Next, an anchor bolt shape search method will be described with reference to the process chart shown in FIG.

In step S <b> 1, the transmission probe 31 transmits a 0-5 MHz broadband input wave (see the input wave broadband spectrum in FIG. 8) in the anchor bolt 30.
In the next step S2, the reception probe 32 receives a broadband received wave (not shown) of 0 to 5 MHz. When the received broadband received wave is Fourier-transformed, a broadband received wave spectrum sp1 (see FIG. 8) can be obtained in step S3.
That is, the first calculation function of the CPU 40, which is a calculation means, obtains the broadband received wave spectrum sp1 from the received broadband received wave by Fourier transform as shown in the left diagram of FIG.

Next, in step S4, the wideband received wave spectrum sp1 of FIG. 8 is multiplied by the spectrum extraction function A (f) (A (f _K ) = 1.0) shown in FIG. chronological wave spectrum (see FIG. 10), sequentially determined in gradually reduced background the center frequency f _K (see step S5).

Here, the spectrum extracting functions _{A (f) (A (f} K) = 1.0) shown in FIG. 9, when the center frequency is _{f K,} a predetermined value is _{f a,} be defined as: Can do.
_f ≦ f K -f _a at A (f) = 0.0
f = f _K and A (f) = 1.0
_f ≧ f K + f _a at A (f) = 0.0
_{f K -f a <f <f} K at A (f) is an increasing function _{f K <f <f K +} f a at A (f) is a decreasing function

In this embodiment, the initial value (maximum value) of the center frequency f _K of the spectrum extraction function A (f) (A (f _K ) = 1.0) is defined for the purpose of clarifying the comparison with the conventional example. Destination is set to f _K = 2.5 MHz, and the wideband received wave spectrum sp1 is multiplied by this spectrum extraction function A (f), and the time series wave of the narrow band spectrum (see FIG. 10A) is obtained by inverse Fourier transform. calculated (see step S4-S5), gradually decreasing the central frequency _{f K,} as shown in FIG. _9, when f K = 1.25 MHz, multiplied by the spectrum extracting function a to the broadband receiving wave spectrum sp1 (f) Then, a time-series wave (see FIG. 10B) of the narrow band spectrum is obtained by inverse Fourier transform (see steps S4 to S5), and the center frequency is further reduced to f _K = 0.99 MHz. Broadband receiver The signal wave spectrum sp1 is multiplied by the spectrum extraction function A (f) to obtain a time-series wave (see c in FIG. 10) of a narrowband spectrum by inverse Fourier transform (see steps S4 to S5).

In other words, repeats the processing of steps S4~S5 each gradually reduced the center frequency f _K, FIG. 10 (b), the as to obtain time-series wave narrowband spectrum as shown in FIG. 10 (c) is there.
That is, the second calculation function of an arithmetic unit CPU40, from the broadband receiving wave spectrum sp1, the center frequency and extracts a narrowband spectrum to f _K, time series wave narrowband spectrum at the inverse Fourier transform (FIG. 10 (b), those found sequentially in the background of gradually decreasing the central frequency _{f K} to 1.25MHz~0.99MHz (c) a reference).

Next, in step S6, the occurrence of a reflected wave from the tip of the anchor bolt 30 is secured from the time-series wave shown in FIGS. 10 (b) and 10 (c).
That is, since the time-series waveforms shown in FIGS. 10A, 10B, and 10C are displayed in real time on the display device 41 in FIG. 1, the reflected wave (e) is confirmed in FIG. However, in FIGS. 10B and 10C, the reflected waves g and h are clearly confirmed, and the operator visually observes the screen of the display device 41 at the moment when the reflected waves g and h start. On the other hand, it can be estimated as the occurrence time t _h of the reflected waves g and h.

なお、図１０（ｂ）（ｃ）に仮想線で示すラインｉは、重み付けのラインであって、このラインｉの高さを波形に乗算し、波形全体における振幅バランスの適性化を図るものである。 As described above, since the occurrence time t _h can be estimated from the reflected waves g and h of the time series waves shown in FIGS. 10B and 10C, the anchor bolt length l _T is calculated based on [Equation 5]. Can be sought.

10B and 10C is a weighted line, and the waveform is multiplied by the height of the line i to optimize the amplitude balance in the entire waveform. is there.

As described above, the anchor bolt shape exploration device according to the first embodiment shown in FIGS. 1 to 10 shares the probe 31 that transmits ultrasonic waves and the probe 32 that receives ultrasonic waves, or the transmission and reception of ultrasonic waves. An anchor bolt shape exploration device for exploring the shape of an anchor bolt 30 that includes a probe 21 that is partially embedded in a concrete structure, and has a wide bandwidth of 0 to 5 MHz from the anchor bolt end face 30a. A first calculation function (COU 40 is provided) that transmits a sound wave, receives a broadband ultrasonic wave of 0 to 5 MHz on the same end face 30a, and obtains a broadband received wave spectrum sp1 (see FIG. 8) by Fourier transform from the received broadband received wave. and function), and extract the narrowband spectrum to f _K the center frequency from the wideband received wave spectrum sp1, chronological wave narrowband spectrum at the inverse Fourier transform (FIG. 10 Of (b), (c) a reference), the center frequency _{f K} is gradually reduced to continue sequentially obtaining second arithmetic function in the Background of the (CPU 40 functions provided), computing means having a (see CPU 40) the provided, and requests from the time-sequential wave, the reflected wave g from the anchor bolt 30 tip, Okoshisei of h (see Okoshisei time t _h).

According to this configuration, the first calculation function of the calculation means CPU40 obtains the broadband received wave spectrum sp1 from the received wideband received wave by Fourier transform, and the second calculation function of the calculation means CPU40 is based on the broadband reception wave spectrum sp1. the center frequency by extracting a narrowband spectrum to f _K, the time-series wave narrowband spectrum at the inverse Fourier transform, so found sequentially in the background of gradually decreasing the central frequency f _K, the time- The occurrence of the reflected waves g and h from the tip of the anchor bolt 30 can be obtained from the series wave (see FIGS. 10B and 10C).

Therefore, even if there is corrosion longitudinal sides of the anchor bolt 30, gradually decreasing the central frequency f _K, less susceptible to decay during ultrasound transmission history by the degree and shape of the corrosion progress of the anchor bolt 30 Since the time series wave is obtained based on the relatively low frequency (refer to 1.25 MHz and 0.99 MHz in the first embodiment), the occurrence of the reflected waves g and h can be secured, and the anchor bolt 30 It can contribute to shape exploration.

The anchor bolt shape exploration method of the first embodiment includes the probe 31 that transmits and receives the ultrasonic wave, or the probe 32 that receives the ultrasonic wave, or the probe 21 that shares the transmission and reception of ultrasonic waves. An anchor bolt shape exploration method for exploring the shape of an anchor bolt 30 partially embedded in a structure, which transmits a broadband ultrasonic wave of 0 to 5 MHz from the anchor bolt end face 30a, First steps S1 and S2 for receiving 0 to 5 MHz broadband ultrasonic waves, and second steps S2 to S3 for obtaining a broadband received wave spectrum sp1 (see FIG. 8) by Fourier transform from the received broadband received waves; extracting a narrowband spectrum with a center frequency f _K from the broadband receiving wave spectrum sp1, chronological wave narrowband spectrum at the inverse Fourier transform (FIG. 10 (b), (c) ginseng The irradiation), and a third step S4~S5 found sequentially in the background of gradually decreasing the central frequency _{f K,} the time-sequential wave (FIG. 10 (b), the (c) to see), the anchor bolt reflected wave g from 30 tip, and a fourth step S6 seeking Okoshisei (see Okoshisei time t _h) of h, those having a (see FIG. 7).

According to this configuration, in the first steps S1 and S2, broadband ultrasonic waves of 0 to 5 MHz are transmitted from the anchor bolt end face 30a, and broadband ultrasonic waves of 0 to 5 MHz are received by the same end face 30a. In the next second steps S2 to S3, a broadband received wave spectrum sp1 is obtained by Fourier transform from the received broadband received wave. In the next third step S4-S5, and extracts the narrowband spectrum to f _K center frequency than the broadband receiving wave spectrum sp1, chronological wave narrowband spectrum at the inverse Fourier transform (FIG. 10 (b ), found sequentially in the background of gradually reduced, the center frequency f _K (c) refer). In the next fourth step S6, the occurrence of the reflected waves g and h from the tip of the anchor bolt 30 is obtained from the time series wave.

Therefore, even if there is corrosion longitudinal sides of the anchor bolt 30, gradually decreasing the central frequency f _K, less susceptible to decay during ultrasound transmission history by the degree and shape of the corrosion progress of the anchor bolt relative Since a time series wave (see FIGS. 10B and 10C) is obtained based on an extremely low frequency (see 1.25 MHz and 0.99 MHz in the first embodiment), the occurrence of the reflected waves g and h is generated. It can be ensured and can contribute to the shape search of the anchor bolt 30.

In the first embodiment, the display device 41 (display means) shown in FIG. 1 generates reflected waves g and h from the tip of the anchor bolt 30 from a time-series wave (see FIGS. 10B and 10C). Display to be visible.
In addition, the numerical values of the center frequencies f _K = 1.25 MHz and f _K = 0.99 MHz disclosed in the first embodiment are merely examples, and the present invention is not limited thereto. Furthermore, the analysis method of the first embodiment can be applied to the total length measurement of the first anchor bolt length, the curved anchor bolt, and the sharpened anchor bolt of the anchor bolt with a welded joint.

[Embodiment 2]
Next, an embodiment for searching for whether or not the anchor bolt 30 as a search target is curved will be described.
11A shows a straight anchor bolt 30 having no curvature, FIG. 11B shows an anchor bolt 30 having a small curvature, FIG. 11C shows an anchor bolt 30 having a medium curvature, and FIG. (D) shows the anchor bolt 30 with a large curvature. 11B, 11C, and 11D are curved anchor bolts.

  FIG. 12 shows, as a comparative example, a received waveform when a 2.5 MHz narrow-band wave is transmitted to each anchor bolt 30 in FIGS. 11A, 11B, 11C, and 11D and the reflected wave is received. The left diagram in FIG. 12 shows the received spectrum wave, and the right diagram in FIG. 12 shows the time-series wave.

  In FIG. In the case of the linear anchor bolt 30 shown in FIG. 1, since the intensity of the received spectrum is large, the occurrence of longitudinal waves and transverse waves M1 and M2 as reflected waves is confirmed, as shown by the time-series wave in the right diagram of FIG. On the other hand, in FIG. 2, no. 3, no. In the case of the curved anchor bolt 30 shown in FIG. 4, since the intensity of the received spectrum is too small, as shown by the time-series wave in the right diagram of FIG. Could not be confirmed.

  In the case of the curved anchor bolt 30, the transmission of ultrasonic waves in the longitudinal direction is as shown in FIGS. 13 (a) and 13 (b). FIG. 13A shows a case where the frequency is 2.5 MHz or higher, and FIG. 13B shows a case where the frequency is 1.25 MHz or lower.

As shown in FIG. 13 (a), when the frequency is 2.5 MHz or higher, the straightness and directivity of the ultrasonic waves are high, and the ultrasonic transmission behavior as shown in the figure is shown in the curved portion of the anchor bolt 30. As a result, the ultrasonic wave is greatly attenuated. As a result, it is assumed that the occurrence of longitudinal waves and transverse waves M1 and M2 cannot be confirmed as already shown in FIG.
On the other hand, as shown in FIG. 13 (b), when the frequency is 1.25 MHz or less, the straightness and directivity of the ultrasonic wave are reduced, and the attenuation rate is also reduced. The ultrasonic transmission behavior is assumed to be as shown in the figure.

The circuit device shown in FIGS. 1 to 5 is also used in the anchor bolt shape exploration method and apparatus shown in the second embodiment. In this second embodiment, the CPU 40 starts from the tip of the anchor bolt 30. Function generating means (see step Q5 in FIG. 14) for generating a time series function (see TGC function in FIG. 17) based on the reflected wave occurrence time t _h (see FIGS. 15 and 16), and the broadband reception described above It also serves as a spectrum calculation means (see steps Q6 and Q7 in FIG. 14) that multiplies the wave by a time series function (TGC function) and obtains the spectrum of the reflected wave related to the anchor bolt length by Fourier transform. When the spectrum stands in a band of a predetermined frequency (for example, 0.45 MHz or more shown in FIG. 17) or higher, the display device 41 displays that it is a straight anchor bolt, and stands for At the time it has, to display a message indicating a curved anchor bolt.

The anchor bolt shape exploration method of the second embodiment will be described in detail below with reference to the process diagram shown in FIG.
In step Q1, the transmission probe 31 transmits a broadband input wave of 0 to 5 MHz (see input wave broadband spectrum in FIG. 8) in the anchor bolt 30.
In the next step Q2, the receiving probe 32 receives a broadband received wave (not shown) of 0 to 5 MHz. When the received broadband received wave is Fourier-transformed, a broadband received wave spectrum sp1 (see FIG. 8) can be obtained in step Q3.
That is, the first calculation function of the CPU 40, which is a calculation means, obtains the broadband received wave spectrum sp1 from the received broadband received wave by Fourier transform as shown in the left diagram of FIG.

Next, in step Q4, the broadband received wave spectrum sp1 in FIG. 8 is multiplied by the spectrum extraction function A (f) (A (f _K ) = 1.0) shown in FIG. 9, for example, f _K = 1.25 MHz. sometimes it extracts a narrowband spectrum sp2 as shown in FIG. _15, when the f K = 0.625 MHz to extract the narrowband spectrum sp3 as shown in FIG. 16, when the narrowband spectrum sp2, sp3 at inverse Fourier transform series wave (Fig. 15, shown at right in FIG. 16), found sequentially in the background of gradually decreasing the central frequency _{f K} (see second operation function in step Q5, CPU 40).

Moreover, in the step Q5, 15, not only determine the time series wave shown in the right diagram of FIG. 16, the Okoshisei time t _h of the reflected wave related l _T from the display device 41 to the time-series waves are displayed reading, creating a TGC function Z1 as shown in the right diagram of FIG. 17 on the basis of the Okoshisei time t _h.
That is, estimates that appear waves is characteristic immediately after Okoshisei time t _h, is to create a TGC function Z1.

The TGC function Z1 shown in FIG. 17 can be defined as follows with Δt as a predetermined value.
0 ≦ t ≦ t _h −Δt and TGC (t) = 0.0
tGC (t) = 1.0 at t = th _h
TGC (t) = 0.0 at t ≦ t _h + Δt
t In _{h -Δt <t} <t _h, with TGC (t) is increasing function _{t h <t <t h +} Δt, TGC (t) is decreasing function Next, at step Q6, the broadband receiving wave TGC function Z1 ( When the spectrum of the reflected wave with respect to the length l _T of the anchor bolt 30 is obtained by Fourier transform (see step Q2), the result is as shown on the left side of FIG.

  In FIG. In the case of 30 in the linear anchor bolt shown by 1, the spectrum stands in a band of a predetermined frequency or higher, specifically, a band of 0.45 MHz or higher. 2-No. In the case of the curved anchor bolt 30 indicated by 4, no spectrum is established in such a band.

Therefore, in the next step Q8 (determination means), it is determined whether or not the spectrum stands in a band equal to or higher than a predetermined frequency (0.45 MHz), and when it stands (when YES is determined), the process proceeds to step Q9. If no forest is established (NO determination), the process proceeds to another step Q10.
In step Q9 (display means), the display device 41 displays that the anchor bolt to be searched is the straight anchor bolt 30 in response to the spectrum being established in a band of a predetermined frequency (0.45 MHz) or higher. On the other hand, in step Q10 (display means), in response to the fact that the spectrum does not stand in a band equal to or higher than the predetermined frequency (0.45 MHz), the display device 41 uses the curved anchor bolt 30 as the search target anchor bolt. A message is displayed.

As described above, the anchor bolt shape exploration device according to the second embodiment shown in FIGS. 11 to 17 is the generation time t _h of the reflected wave from the tip 30a of the anchor bolt 30 (the right diagram of FIGS. 15 and 16). And a function creation means (see step Q5) for creating a TGC function (see the right figure in FIG. 17) Z1 as a time series function, and multiplying the broadband received wave by the TGC function Z1 to obtain an anchor bolt length. the spectrum of the reflected wave related l _T provided a spectrum calculating means for calculating at the Fourier transform (step Q6, Q7), when the spectrum is bristling with a predetermined frequency (0.45 MHz) band above, determines that the straight line anchor bolt When the forest does not stand, it is determined to be a curved anchor bolt (see step Q8 as a determination unit and steps Q9 and Q10 as a display unit).

According to this configuration, the function creating means (step Q5) is based on the TGC function Z1 (see FIG. 15 and FIG. 16 on the right side) based on the occurrence time t _h of the reflected wave from the tip 30a of the anchor bolt 30. 17), and the spectrum calculation means (steps Q6 and Q7) multiplies the wideband received wave by the TGC function Z1 and obtains the spectrum of the reflected wave related to the anchor bolt length l _T by Fourier transform. When the spectrum stands in a band of a predetermined frequency or higher, it can be determined as a straight anchor bolt 30, and when the spectrum does not stand, it can be determined as a curved anchor bolt 30.
As a result, it is possible to determine whether the anchor bolt to be measured (search target) is the straight anchor bolt 30 or the curved anchor bolt 30.

[Embodiment 3]
Next, the anchor bolt 30 as an exploration target is a single anchor bolt 30 as shown in FIG. 18 (a), or a welded joint 29 is connected via a welding surface j as shown in FIG. 18 (b). An embodiment for searching for the anchor bolt 30 with a joint will be described.

In the case of exploration with the configuration of the first embodiment, the reflected wave is related to the single anchor bolt length l _{1 at} the position of the weld surface j, and this length l ₁ is misidentified as the anchor bolt total length l _T. The third embodiment is configured to avoid this.

A transmitting probe 31 and a receiving probe 32 are arranged on an anchor bolt 30 shown in FIGS. 18A and 18B, and a broadband received wave of 0 to 5 MHz obtained by the receiving probe 32 is Fourier transformed. Then, after obtaining the wideband received wave spectrum sp1 (see FIG. 8), the wideband received wave spectrum sp1 is multiplied by the spectrum extraction function A (f) (A (f _K ) = 1.0), for example, the center frequency When f _K = 0.937 MHz, the narrowband spectrum sp4 shown in the left diagram of FIG. 20 can be extracted, and when this is inverse Fourier transformed, the time series wave shown in the right diagram of FIG. 20 can be obtained. .

In the right diagram of FIG. 1 time series wave of a genuine anchor bolt 30, As shown by the time series wave of the anchor bolt 30 with two joints, these two are almost the same, and it is impossible to distinguish whether there is a joint or not. That is, no. No. 1 single anchor bolt 30 is also No. 1. Both of the two anchor bolts 30 with joints are in a state of occurrence of overlapping reflected waves with respect to the first anchor bolt length l ₁ , and it is impossible to determine the shape distinction with and without joints.

  In the third embodiment, the anchor bolt 30 with the weld joint 29 or the anchor bolt 30 without the weld joint 29 can be distinguished, and in the low frequency region (20 kHz to 120 kHz) of the reflected wave. It pays attention to an unknown physical phenomenon that the frequency (dominant frequency) differs between the single anchor bolt 30 and the anchor bolt 30 with a joint.

The structure of this Embodiment 3 is demonstrated with the effect | action with reference to the process drawing shown in FIG.
In step U1, the transmission probe 31 transmits a broadband input wave of 0 to 5 MHz (see input wave broadband spectrum in FIG. 8) in the anchor bolt 30.
In the next step U2, the receiving probe 32 receives a broadband received wave (not shown) of 0 to 5 MHz. When the received broadband received wave is Fourier-transformed, a broadband received wave spectrum sp1 (see FIG. 8) can be obtained in step U3.
That is, the first calculation function of the CPU 40, which is a calculation means, obtains the broadband received wave spectrum sp1 from the received broadband received wave by Fourier transform as shown in the left diagram of FIG.

Next, in step U4, a spectrum group in the frequency band (20 kHz to 120 kHz low frequency region) including the occurrence spectra A and B as shown in the left diagram of FIG. 21 is extracted from the wideband received wave spectrum sp1 of FIG. To do.
The extraction of the spectrum group may be performed either by a general bandpass method or by using the already described spectrum extraction function A (f) (A (f _K ) = 1.0).

  The region (A region) of the occurrence spectrum A in the lowest frequency band shown in FIG. 21 is around 37 kHz, specifically, the range of 25.3 kHz to 49.2 kHz and the occurrence spectrum B in the next lower frequency band. The region (B region) is in the vicinity of 70 kHz, specifically 60.9 kHz to 91.9 kHz.

  Next, in step U5 (time series wave calculating means), the spectrum group of the frequency band (20 to 120 kHz) including the origination spectra A and B is subjected to Fourier inverse transform, and the time series wave corresponding to the spectrum group is represented in FIG. It calculates | requires as shown in the right figure of 21.

In FIG. 1, no. 2 is a single anchor bolt 30, No. 2 3, no. Reference numeral 4 denotes an anchor bolt 30 with a joint.
FIG. 21 shows the occurrence time t _h of the longitudinal wave P, the occurrence time t _M1 of the transverse wave _M1, and the occurrence time t _M2 of the transverse wave M2, and the corresponding cursors are indicated by dotted lines. Yes. In this case, if the length of the anchor bolt 30 is an existing value, the times t _h , t _M1 , and t _M2 can be obtained by calculation.

Here, Okoshisei time _{t h} in FIG. 21 is a Okoshisei time of the reflected wave (longitudinal wave P) from the tip 30b one real anchor bolt 30 shown in FIG. 22 (a), Okoshisei time of FIG. 21 t _M1 is the time of occurrence of the transverse wave M1 generated on the weld surface j as the joint shown in FIG. 22B, and the time of occurrence t _{M2 in} FIG. 21 is the anchor bolt end face 30a shown in FIG. 22C. This is the time of occurrence of the reflected wave (transverse wave M2) from the first tip 30b of the longitudinal wave in the longitudinal direction of the anchor bolt 30 that naturally occurs when the longitudinal wave is input from.

Next, at step U6 (TGC function operation means), along with determining the TGC function Z2 of FIG. 23 on the basis of Okoshisei time _{t M2,} obtains the TGC function Z3 of FIG. 24 on the basis of Okoshisei time _{t M1.}
Further, in this step U6, the time series wave (see the right figure in FIG. 21) obtained in the previous step U5 is multiplied by the TGC functions Z2 and Z3 (see the right figures in FIG. 23 and FIG. 24), and the next step U7. Thus, the spectra of the A and B regions cut out by the TGC functions Z2 and Z3 are obtained by Fourier transform.

The spectra of the A and B regions cut out by the TGC functions Z2 and Z3 are shown in FIGS. 23 and 24, respectively.
As is apparent from the spectrum occurrence situation in FIGS. 1, no. The reflected waves M1 and M2 (waves indicated by solid lines in FIG. 23 and FIG. 24 and waves indicated by dotted lines) relating to l ₁ of the single anchor bolt 30 indicated by 2 are spectrums on the side of the A region where the frequency is relatively low. Is outstanding. 3, no. Reflected wave M1 about l ₁ of the joint has an anchor bolt 30 shown in 4, M2 (FIG. 23, and wave indicated by the two-dot chain line in FIG. 24, the wave indicated by a chain line) is relatively higher frequency region B The spectrum is outstanding on the side.

As is apparent from FIGS. 1, no. Since the reflected waves M1 and M2 related to l ₁ of the single anchor bolt 30 shown in FIG. 2 are greatly attenuated in the B region, the spectral state in the B region is determined as the main, and the spectral state in the A region is determined as the sub. can do.

  Therefore, in the next step U8 (determination means), it is determined whether the spectrum is superior in any region A or B. When it is determined that the spectrum is superior in the A region, the process proceeds to the next step U9. When it is determined that the area B is superior, the process proceeds to another step U10.

In step U9 (display means) described above, in response to the spectrum being excellent in the A region, the display device 41 displays that the anchor bolt to be searched is a single anchor bolt 30, while In U10 (display means), in response to the spectrum being superior in the B region, the display device 41 displays that the anchor bolt to be searched is the anchor bolt 30 with a joint.
In this way, it is possible to easily search whether the anchor bolt to be searched is the single anchor bolt 30 or the anchor bolt 30 with a joint.

[Embodiment 4]
In the third embodiment, the case where the anchor bolt length is known has been described. In this fourth embodiment, when the anchor bolt length is unknown, the anchor bolt to be searched is the single anchor bolt 30 or the anchor bolt with joint. Search for 30.

により計算する計算手段（図２５のステップＸ２参照）と、上記広帯域受信波スペクトルｓｐ５（図２６参照）において、最低周波数帯域（２５．３〜４９．２ｋＨｚ）の起生スペクトルをＡとし、次に低い周波数帯域（６０．９〜９１．９ｋＨｚ）の起生スペクトルをＢとした時、起生スペクトルＡ、Ｂを含む周波数帯域（２０ｋＨｚ〜１２０ｋＨｚ）のスペクトル群を抽出し、フーリエ逆変換にて上記スペクトル群に対応する時系列波を求める時系列演算手段（図２５のステップＸ５参照）と、上記横波Ｍ１，Ｍ２の起生時刻ｔ_Ｍ１，ｔ_Ｍ２の値に基づいて所定の時系列関数としてのＴＧＣ関数をＡ、Ｂスペクトル群に対応する時系列波に乗ずることで、この時刻ｔ_Ｍ１，ｔ_Ｍ２より生ずる横波Ｍ１，Ｍ２を抽出し、この抽出波のスペクトルをフーリエ変換で求めるスペクトル演算手段（図２５の各ステップＸ６，Ｘ７参照）とを兼ねる。 In the embodiment 4, CPU 40 shown in FIG. 1 the Okoshisei time of the reflected wave from the anchor bolt 30 tip and t _h, the sound velocity ratio between the transverse and longitudinal waves for transmitting the anchor bolt longitudinal direction (i.e., transverse waves Ε ₁ is the speed of sound ÷ longitudinal wave speed of sound = 0.54), and the transverse wave M1 generated at the joint portion of the anchor bolt 30 (see welding surface j) and the longitudinal transverse wave M2 generated when ultrasonic waves are input from the end face of the anchor bolt 30 The time of occurrence (t _M1 , t _M2 ) with

In the calculation means (see step X2 in FIG. 25) calculated by the above and the broadband received wave spectrum sp5 (see FIG. 26), the occurrence spectrum of the lowest frequency band (25.3-39.2 kHz) is A, When the origin spectrum of the low frequency band (60.9 to 91.9 kHz) is B, the spectrum group of the frequency band (20 kHz to 120 kHz) including the origin spectra A and B is extracted, and the above is performed by inverse Fourier transform. Time series calculation means for obtaining a time series wave corresponding to the spectrum group (see step X5 in FIG. 25) and a predetermined time series function based on the values of the occurrence times t _M1 and t _M2 of the transverse waves M1 and M2 by multiplying the TGC function a, in time series waves corresponding to B spectrum group, to extract the shear wave M1, M2 arising from the time _{t M1, t M2,} scan of the extracted wave Vector serving as a spectrum calculating means for calculating the Fourier transform (see steps X6, X7 of FIG. 25) a.

The display device 41 as the display means has a single anchor bolt and no welded joint when only the spectrum of the B region of the spectrums of the A and B regions disappears in both the spectra of M1 and M2. On the other hand, only the B region spectrum of the A and B region spectra disappears in the spectrum of M1, and only the A region spectrum of the A and B region spectra disappears in the M2 spectrum. Or when it attenuates greatly, it indicates that the anchor bolt has a welded joint.
Also in the fourth embodiment, the circuit device shown in FIGS. 1 to 5 is used.

Next, an anchor bolt shape search method will be described with reference to the process chart shown in FIG.
In step X1, the transmission probe 31 transmits a broadband input wave of 0 to 5 MHz (see input wave broadband spectrum in FIG. 8) in the anchor bolt 30.
In the next step X2, the receiving probe 32 receives a broadband received wave α (see FIG. 26) of 0 to 5 MHz. This broadband receiving wave α is displayed on the display device 41, reading the Okoshisei time t _h from the reflected wave (P-wave).

From this Okoshisei time _{t h,} the above Equation 1, based on the formula [2], determined to Okoshisei time _{t M1} of transverse waves M1, and Okoshisei time _{t M2} shear wave M2 in the calculation, memory 43 is readably stored. Note that the No. of the wideband received wave α shown in the right diagram of FIG. 1 and no. The two are the same.
When the broadband received wave α is Fourier-transformed, a broadband received wave spectrum sp5 shown in the left diagram of FIG. 26 can be obtained in step X3.

  Next, in step X4, a spectrum group including an occurrence spectrum A in the lowest frequency band and an occurrence spectrum B in the next lower frequency band is extracted from the wideband received wave spectrum sp5 in FIG. 26 (left in FIG. 27). (See figure).

The region (A region) of the occurrence spectrum A in the lowest frequency band shown in FIG. 27 is in the vicinity of 37 kHz, specifically, the range of 25.3 kHz to 49.2 kHz, and the occurrence spectrum B of the next lower frequency band. The region (B region) is in the vicinity of 70 kHz, specifically, in the range of 60.9 kHz to 91.9 kHz, and the extraction of this spectrum group may be a general bandpass method, or as described above. Extraction using the spectrum extraction function A (f) (A (f _K ) = 1.0) may be used.

Next, in step X5, the extracted spectrum shown in the left diagram of FIG. 27 is Fourier transformed to obtain a time series wave (see the right diagram of FIG. 27) corresponding to the spectrum group. In the right diagram of FIG. 1, no. The time series waves indicated by 2 are the same.
Next, in step X6, the occurrence times t _M1 and t _{M2 of} the transverse waves M1 and M2 calculated in advance in step X2 or the estimated values t to _M1 and t to _{M2 of} the occurrence times (where t is the t in the equation) Based on the above, the TGC functions Z4 and Z5 shown in FIGS. 28 and 29 are obtained. In step X6, the TGC functions Z4 and Z5 are calculated. chronological wave by multiplying (Figure 28, shown at right in FIG. 29), to extract the shear wave M1, M2 arising from the estimated value t ~ _M1, t ~ _M2, spectrum extraction wave (M1 wave spectrum, M2 Wave spectrum) is obtained by Fourier transform (see step X7).

  28 and 29, the spectrum of the M1 wave is indicated by a solid line, and the spectrum of the M2 wave is indicated by a dotted line. FIG. 28 is a spectrum occurrence diagram of a single anchor bolt 30 and FIG. 29 is a spectrum occurrence diagram of the anchor bolt 30 with a joint. As shown in FIG. When the spectrum of the B region disappears among the spectra of the B region and the B region, the anchor bolt is single.

On the other hand, as shown in FIG. 29, when the B region spectrum disappears in the M1 spectrum and the A region spectrum disappears or greatly attenuates in the M2 spectrum, the anchor bolt has a joint. .
Therefore, in the next step X8 (determination means), the spectral conditions of both the A and B regions are determined, and when it is determined that both the M1 wave and M2 wave spectra have disappeared in the B region (FIG. 28). In the case where it is determined that the M1 wave disappears in the B region and the M2 wave disappears or greatly attenuates in the A region (corresponding to FIG. 29). The process proceeds to another step X10.

  In response to the disappearance of both the M1 wave and M2 wave spectra in the B region in step X9 (display means) described above, the display device 41 uses a single anchor bolt 30 as the search target anchor bolt. On the other hand, in step X10 (display means), in response to the M1 wave disappearing in the B region and the M2 wave disappearing or greatly attenuated in the A region, the display device 41 searches. The fact that the target anchor bolt is the anchor bolt 30 with a joint is displayed.

In this way, it is possible to easily search whether the anchor bolt to be searched is the single anchor bolt 30 or the anchor bolt 30 with a joint.
As is clear from the comparison between FIG. 28 and FIG. 29, whether the spectrum of the M2 wave (see the dotted wave in the same figure) is large or small in the B region, whether the anchor bolt 30 with a joint or the anchor bolt 30 with a joint is used. May be determined. That is, in the case of the single anchor bolt 30, the spectrum disappears in the B region as shown in FIG. 28, whereas in the case of the anchor bolt 30 with a joint, the spectrum in the B region as shown in FIG. Since it has a large strength, it can be easily determined by this method.

  In place of the TGC functions Z4 and Z5 shown in FIGS. 28 and 29, TGC functions Z6 and Z7 such as substantially trapezoidal waves shown in FIGS. 30 and 31 may be used. 30 is a spectrum occurrence diagram of a single anchor bolt 30 corresponding to FIG. 28, and FIG. 31 is a spectrum occurrence diagram of the anchor bolt 30 with a joint corresponding to FIG. 29, based on the process diagram of FIG. Since the processing contents are the same, detailed description thereof is omitted.

により計算する計算手段（ステップＸ２参照）と、上記広帯域受信波スペクトルｓｐ５（図２６参照）において、最低周波数帯域の起生スペクトルをＡとし、次に低い周波数帯域の起生スペクトルをＢとした時、起生スペクトルＡ、Ｂを含む周波数帯域（２０ｋＨｚ〜１２０ｋＨｚ）のスペクトル群を抽出（図２７の左図参照）し、フーリエ逆変換にて上記スペクトル群に対応する時系列波（図２７の右図参照）を求める時系列演算手段（ステップＸ５参照）と、上記横波Ｍ１，Ｍ２の起生時刻ｔ_Ｍ１，ｔ_Ｍ２の値に基づいて所定の時系列関数（ＴＧＣ関数Ｚ４，Ｚ５またはＴＧＣ関数Ｚ６，Ｚ７参照）をＡ、Ｂスペクトル群に対応する時系列波に乗ずることで、この時刻ｔ_Ｍ１，ｔ_Ｍ２より生ずる横波Ｍ１，Ｍ２を抽出し、この抽出波のスペクトル（図２８、図２９の左図参照）をフーリエ変換で求めるスペクトル演算手段（ステップＸ６，Ｘ７参照）とを備え、Ｍ１，Ｍ２のスペクトルの双方で、ＡおよびＢ領域のスペクトルのうち、Ｂ領域のスペクトルのみが消滅する時（図２８参照）、アンカボルト３０が一本物で溶接継手なしと判断（判定手段としてのステップＸ８参照）する一方、Ｍ１のスペクトルにおいて、ＡおよびＢ領域のスペクトルのうち、Ｂ領域スペクトルのみが消滅し、かつＭ２のスペクトルにおいて、ＡおよびＢ領域のスペクトルのうち、Ａ領域スペクトルのみが消滅、または大きく減衰する時（図２９参照）、アンカボルト３０が溶接継手ありと判断（判定手段としてのステップＸ８参照）するものである。 As described above, in the fourth embodiment shown in FIGS. 25 to 31, the generation time of the reflected wave from the tip of the anchor bolt 30 is set to t _h (see FIG. 26), and the transverse wave is transmitted in the longitudinal direction of the anchor bolt 30. And the ultrasonic wave from the end face 30a of the anchor bolt and the transverse wave M1 generated at the joint portion of the anchor bolt 30 (see weld surface j), where the sound speed ratio between the longitudinal wave and the longitudinal wave is ε ₁ (specifically ε ₁ = 0.54). The time of occurrence (t _M1 , t _M2 ) with the longitudinal transverse wave M2 generated at the time of input,

In the calculation means (see step X2) calculated by the above and the broadband received wave spectrum sp5 (see FIG. 26), the starting spectrum in the lowest frequency band is A, and the starting spectrum in the next lower frequency band is B , A spectrum group in the frequency band (20 kHz to 120 kHz) including the origination spectra A and B is extracted (see the left diagram in FIG. 27), and a time series wave corresponding to the spectrum group by inverse Fourier transform (right in FIG. 27) Time series calculating means (see step X5) for obtaining a predetermined time series function (TGC functions Z4, Z5 or TGC function Z6) based on the values of the occurrence times t _M1 and t _M2 of the transverse waves M1 and M2. , by multiplying the reference Z7) a, in time series waves corresponding to B spectrum group, to extract the shear wave M1, M2 arising from the time _{t M1, t M2,} the extracted wave Spectrum calculation means (see Steps X6 and X7) for obtaining a spectrum (see the left diagrams of FIGS. 28 and 29) by Fourier transform, and both of the spectra of M1 and M2 are B When only the spectrum of the region disappears (see FIG. 28), it is determined that the anchor bolt 30 is a single one and no welded joint (see step X8 as the judging means), while in the spectrum of M1, the spectrum of the A and B regions Of these, when only the B region spectrum disappears and only the A region spectrum of the A2 and B region spectra disappears or greatly attenuates in the M2 spectrum (see FIG. 29), the anchor bolt 30 has a welded joint. (Refer to step X8 as a determination means).

  In this embodiment, the above-mentioned lowest frequency band (A region) is set to 25.3 kHz to 49.2 kHz around 37 kHz, and the next lower frequency band (B region) is 60.9 kHz to 91.9 kHz around 70 kHz. However, it is not limited to this value.

According to this configuration, the calculating means (see step X2) calculates the occurrence times t _M1 and t _M2 of the transverse waves M1 and M2 based on the above [Equation 1] and [Equation 2], and the time series wave computing means (See step X5) extracts a spectrum group of the frequency band (20 kHz to 120 kHz) including the occurrence spectra A and B, obtains a time series wave corresponding to the spectrum group by inverse Fourier transform, and calculates a spectrum calculation means ( In steps X6 and X7), a predetermined time series function (TGC function) is multiplied by the time series wave corresponding to the A and B spectrum groups based on the values of the occurrence times t _M1 and t _M2 of the transverse waves M1 and M2. in extracts shear M1, M2 arising from the time _{t M1, t M2,} the spectrum of the extracted wave (spectrum of M1-wave spectrum of M2 wave) (see FIG. 28, FIG. 29) by the Fourier transform Therefore, when only the spectrum of the B region disappears in both the spectra of M1 and M2 (see FIG. 28), it can be determined that the anchor bolt 30 is a single one and no welded joint, while M1 If only the B region spectrum disappears and only the A region spectrum disappears or greatly declines in the M2 spectrum (see FIG. 29), it can be determined that the anchor bolt 30 has a welded joint. .

  As a result, it is possible to determine whether the anchor bolt 30 to be measured (exploration target) is a single anchor bolt without a welded joint or an anchor bolt with a welded joint.

In correspondence between the configuration of the present invention and the above-described embodiment,
The probe for transmitting ultrasonic waves according to the present invention corresponds to the transmission probe 31 of the embodiment,
Similarly,
The receiving probe corresponds to the receiving probe 32,
The probe that shares transmission and reception of ultrasonic waves corresponds to the probe 21,
The computing means corresponds to the CPU 40,
The first process corresponds to steps S1 and S2,
The second process corresponds to steps S2 and S3,
The third process corresponds to steps S4 and S5,
The fourth process corresponds to step S6,
The function creation means corresponds to step Q5,
The spectrum calculation means corresponds to steps Q6 and Q7,
The calculation means corresponds to step X2,
The time series wave calculating means corresponds to step X5,
The spectrum calculation means corresponds to steps X6 and X7,
The present invention is not limited to the configuration of the above-described embodiment.

21 ... Probe 30 ... Anchor bolt 31 ... Transmission probe 32 ... Reception probe 40 ... CPU (calculation means)
S1, S2 ... 1st step S2, S3 ... 2nd step S4, S5 ... 3rd step S6 ... 4th step Q5 ... Function creation means Q6, Q7 ... Spectrum calculation means X2 ... Calculation means X5 ... Time series Wave calculation means X6, X7 ... spectrum calculation means

Claims (4)

Equipped with a probe that transmits and receives ultrasound, or a probe that shares transmission and reception of ultrasound,
An anchor bolt shape exploration device for exploring the shape of an anchor bolt partially embedded in a concrete structure,
Broadband ultrasonic waves are transmitted from the anchor bolt end face, and broadband ultrasonic waves are received at the same end face,
A first calculation function for obtaining a broadband received wave spectrum by Fourier transform from the received broadband received wave;
The wide band receiver wave spectrum than the center frequency by extracting a narrowband spectrum to f _K, the time-series wave narrowband spectrum at the inverse Fourier transform, in a background of gradually decreasing the central frequency f _K A second calculation function to be obtained sequentially;
Provided with a computing means comprising
An anchor bolt shape exploration device that determines the occurrence of a reflected wave from the tip of the anchor bolt from the time series wave. And function generating means for generating a time-series function based on Okoshisei time t _h of the reflected waves from the tip of the anchor bolt,
Spectral calculation means for multiplying the broadband received wave by a time series function and obtaining a spectrum of the reflected wave related to the anchor bolt length by Fourier transform,
2. The anchor bolt shape exploration device according to claim 1, wherein when the spectrum stands in a band of a predetermined frequency or higher, it is determined as a straight anchor bolt, and when it is not forested, it is determined as a curved anchor bolt. The time of occurrence of the reflected wave from the tip of the anchor bolt is defined as t _h ,
Assuming that the sound speed ratio between the transverse wave and the longitudinal wave transmitted in the longitudinal direction of the anchor bolt is ε ₁ ,
The time of occurrence (t _M1 , t _M2 ) of the transverse wave M1 generated at the anchor bolt joint and the longitudinal transverse wave M2 generated when ultrasonic waves are input from the end face of the anchor bolt,

A calculation means for calculating by
In the above broadband received wave spectrum, A is the occurrence spectrum of the lowest frequency band,
When the origin spectrum of the next lower frequency band is B,
A time series computing means for extracting a spectrum group in a frequency band including the occurrence spectra A and B and obtaining a time series wave corresponding to the spectrum group by inverse Fourier transform;
Based on the values of the occurrence times t _M1 and t _M2 of the transverse waves M1 and M2, a predetermined time series function is multiplied by the time series waves corresponding to the A and B spectrum groups, thereby generating the times t _M1 and t _M2. Extract the transverse waves M1 and M2,
Spectrum calculating means for obtaining the spectrum of the extracted wave by Fourier transform,
In both of the spectra of M1 and M2, when only the spectrum of the B region is extinguished among the spectra of the A and B regions, it is determined that the anchor bolt is single and there is no weld joint,
In the spectrum of M1, only the B region spectrum of the A and B region spectra disappears, and in the M2 spectrum, only the A region spectrum of the A and B region spectra disappears or greatly attenuates. The anchor bolt shape exploration device according to claim 1, wherein the anchor bolt is determined to have a welded joint. Equipped with a probe that transmits and receives ultrasound, or a probe that shares transmission and reception of ultrasound,
An anchor bolt shape exploration method for exploring the shape of an anchor bolt partially embedded in a concrete structure,
A first step of transmitting broadband ultrasonic waves from the anchor bolt end face and receiving broadband ultrasonic waves at the same end face;
A second step of obtaining a broadband received wave spectrum by Fourier transform from the received broadband received wave;
Extracting a narrowband spectrum with a center frequency f _K from the broadband receiving wave spectrum, time series wave narrowband spectrum at the inverse Fourier transform, sequential in circumstances which gradually reduce the center frequency f _K A third step to be obtained;
A fourth step of obtaining an occurrence of a reflected wave from the tip of the anchor bolt from the time-series wave, and a method for exploring the shape of the anchor bolt.

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