Method and system for detecting and imaging abnormal body in hydraulic mass concrete

Abstract

The invention relates to the field of water conservancy, and discloses a detection imaging method and system for an abnormal body in hydraulic mass concrete, and the method comprises the steps: carrying out the field elastic wave data collection through employing a single-side common-shot point array type knocking scanning sampling mode, carrying out the amplitude gain compensation and time difference correction processing of the collected elastic wave data, and carrying out the detection imaging of the abnormal body in the hydraulic mass concrete; reconstructing an elastic wave signal through time difference correction, and obtaining an abnormal point reflected wave; reconstructing the elastic wave signals at all positions in the detection area, and performing waveform superposition processing on the reconstructed signals to obtain superposed signals; and imaging the superposed signal by adopting focusing imaging, and identifying the abnormal body in the large-volume concrete according to an imaging result. The influence of a reinforcing steel bar layer in the hydraulic mass concrete on electromagnetic wave detection is avoided, and the deep area of the mass concrete, which is difficult to detect by ultrasonic waves, is also detected.

Description

Technical Field

[0001] The present invention relates to the field of water conservancy, and specifically to a method and system for detecting and imaging abnormal bodies inside large-volume hydraulic concrete. Background Art

[0002] In the field of hydraulic engineering, the internal quality inspection of large-volume concrete structures is a key link to ensure the safety and stability of the project. Traditionally, for the detection of abnormal bodies inside concrete (such as cavities, cracks, foreign objects, etc.), electromagnetic waves or ultrasonic technologies are mostly used. However, these methods face significant challenges in the application of large-volume hydraulic concrete: on the one hand, the dense steel bar network inside the concrete will seriously interfere with the propagation of electromagnetic waves, reducing the detection accuracy; on the other hand, due to the fast attenuation and limited penetration of ultrasonic waves, it is difficult to effectively detect abnormalities in the deep area of the concrete. Summary of the Invention

[0003] The purpose of the present invention is to overcome the deficiencies of the prior art and provide a method for detecting and imaging abnormal bodies inside large-volume hydraulic concrete, including the following steps: Step 1, perform on-site elastic wave data acquisition using a single-sided common-shotpoint array percussion scanning sampling method. By using a single-sided hammering source, arrange geophones in an array at equal distances on one side of the source to simultaneously receive signals; the hammering source rolls and hammers along the arrangement direction and position of the geophones until it hammers to the (n - 1)-th hammering point; Step 2, perform amplitude gain compensation and time difference correction processing on the collected elastic wave data, reconstruct the elastic wave signal through time difference correction, and obtain the reflected wave of the abnormal point; Step 3, according to the travel time t of the reflected wave of the abnormal point reaching geophone n, obtain the time point serial number of the abnormal point when the waveform is received by geophone n, and extract the elastic wave sampling value of geophone n at the corresponding time point serial number, and reconstruct the elastic wave signal at any depth with geophone n as the anchor point under the Mi position; Step 4, reconstruct the elastic wave signals at all positions in the detection area, and perform waveform superposition processing on the reconstructed signals to obtain the superimposed signal; Step 5, perform imaging on the superimposed signal using focused imaging, and identify the abnormal bodies inside the large-volume hydraulic concrete according to the imaging results.

[0004] Furthermore, the performing amplitude gain compensation and time difference correction processing on the collected elastic wave data, reconstructing the elastic wave signal through time difference correction, and obtaining the reflected wave of the abnormal point includes: Among them, the amplitude gain compensation is: A compensated = A original × G Among them A compensated is the compensated amplitude, A original is the original amplitude, G is the gain coefficient; The time difference correction is: t corrected = t measured −Δ t Among them t corrected is the corrected time, t measured is the measured time, Δ t is the time difference; To reconstruct the elastic wave signal, the following formula is used: p ( x , t ) = P sin( kx − ωt + ϕ ) Where: P is the amplitude, k = QUOTE is the wave number, λ is the wavelength; ω = 2 πf is the angular frequency, f is the frequency; ϕ is the initial phase, indicating the phase of the wave at the initial moment.

[0005] Furthermore, based on the travel time t of the reflected wave from the anomaly point reaching the detector n, the time point serial number of the waveform received by the detector at the anomaly point is obtained, and the elastic wave sampling value corresponding to the time point serial number of the detector n is extracted to reconstruct the elastic wave signal at any depth with the detector n as the anchor point under the Mi position, including: The travel time t of the reflected waveform of the anomaly point at the depth h under the Mi position between the right side of the shot point and any detector n position with an offset of x reaching the detector is: Where: t is the travel time of the reflected wave; d is the distance between the Mi position and the detector; β is the angle between the line connecting the anomaly point and the detector and the horizontal plane; v is the elastic wave velocity.

[0006] Furthermore, reconstructing the elastic wave signals at all positions in the detection area and performing waveform superposition processing on the reconstructed signals to obtain the superimposed signal, including: Elastic wave signals at all positions within the detection area p ( x , t ) are reconstructed, and waveform superposition processing is performed on the reconstructed signals to obtain the superimposed signal P 叠加 ( t ) = ∑ p ( x i , t ), i = 1, 2, …, n.

[0007] Furthermore, the superimposed signal is imaged using focused imaging to identify anomalies inside the large-volume hydraulic concrete, including: The imaging process is expressed as: I ( x , y , z ) = F{ P 叠加 ( t )} wherein, I ( x , y , z ) represents the intensity distribution in the imaging space, F represents the focused imaging algorithm, and the time-domain signal P 叠加 ( t ) is converted into a spatial-domain image to identify anomalies inside the concrete D .

[0008] A detection and imaging system for anomalies inside large-volume hydraulic concrete, corresponding to the described method for detecting and imaging anomalies inside large-volume hydraulic concrete, includes: an elastic wave acquisition module, a data processing module, and an imaging module; the imaging module and the elastic wave acquisition module are respectively connected to the data processing module; The elastic wave acquisition module is used to perform single-sided common-shotpoint array percussion scanning sampling; The data processing module is used to perform amplitude gain compensation, time difference correction, signal reconstruction, and waveform superposition processing on the acquired elastic wave data; The imaging module uses focused imaging technology to image the processed signal and generate an image of the anomalies inside the concrete.

[0009] Preferably, the elastic wave acquisition module includes a hammer shock source module and an array geophone module, and the hammer shock source module and the array geophone module are respectively connected to the data processing module.

[0010] Preferably, it further includes a time difference correction unit, which is connected to the data processing module. The time difference correction unit performs precise time correction on the elastic wave signal according to a preset travel time formula.

[0011] Preferably, the imaging module includes a focused imaging unit and an anomaly recognition module, which are respectively connected to the data processing module.

[0012] The beneficial effects of the present invention are: an array elastic wave acquisition system for abnormal bodies inside hydraulic large-volume concrete, time difference correction of the data in the acquired elastic waves, extraction of reflected waves, and imaging of underground abnormal bodies. This aspect avoids the influence of the steel bar layer in hydraulic large-volume concrete on electromagnetic wave detection and also achieves the deep area of large-volume concrete that is difficult to detect by ultrasonic waves. Description of the Drawings

[0013] Figure 1 It is a schematic flow chart of a method for detecting and imaging abnormal bodies inside hydraulic large-volume concrete; Figure 2 It is a schematic principle diagram of a system for detecting and imaging abnormal bodies inside hydraulic large-volume concrete; Figure 3 It is a schematic diagram of the on-site elastic wave data acquisition method; Figure 4 It is a schematic diagram before and after reconstruction (a) is the imaging schematic diagram before correction processing; (b) is the imaging schematic diagram after reconstruction processing. Detailed Embodiments

[0014] The technical solutions of the present invention will be further described in detail below with reference to the drawings, but the protection scope of the present invention is not limited to the following.

[0015] The features and performance of the present invention will be further described in detail below with reference to the embodiments.

[0016] As Figure 1 shown, a method for detecting and imaging abnormal bodies inside hydraulic large-volume concrete includes the following steps: Step 1, perform on-site elastic wave data acquisition by using a single-side common shot-point array percussion scanning sampling method. By using a single-side hammering source, arrange geophones in an array at equal distances on one side of the source to receive signals simultaneously; the hammering source rolls and hammers along the arrangement direction and position of the geophones until it hammers to the (n - 1)th hammering point; Step 2, perform amplitude gain compensation and time difference correction processing on the acquired elastic wave data, reconstruct the elastic wave signal through time difference correction, and obtain the reflected wave of the abnormal point; Step 3: Based on the travel time \(t\) of the reflected wave from the anomaly point reaching the geophone \(n\), obtain the time point sequence number of the waveform received by the geophone \(n\) for the anomaly point, and extract the elastic wave sampling values at the corresponding time point sequence number of the geophone \(n\) to reconstruct the elastic wave signal at any depth with the geophone \(n\) as the anchor point under the position \(M_i\); Step 4: Reconstruct the elastic wave signals at all positions in the detection area, and perform waveform superposition processing on the reconstructed signals to obtain the superimposed signal; Step 5: Use focused imaging to image the superimposed signal, and identify the anomalies inside the large mass concrete of the hydraulic structure according to the imaging results.

[0017] The amplitude gain compensation and time difference correction processing of the collected elastic wave data, reconstructing the elastic wave signal through time difference correction, and obtaining the reflected wave of the anomaly point include: Among them, the amplitude gain compensation is: A compensated = A original × G Among them A compensated is the compensated amplitude, A original is the original amplitude, G is the gain coefficient; The time difference correction is: t corrected = t measured −Δ t Among them t corrected is the corrected time, t measured is the measured time, Δ t is the time difference; To reconstruct the elastic wave signal, use the following formula: p ( x , t )= P sin( kx − ωt + ϕ ) Among them: P is the amplitude, k = QUOTE is the wave number, λ is the wavelength; ω =2 πf is the angular frequency, f is the frequency;ϕ is the initial phase, representing the phase of the wave at the initial moment.

[0018] According to the travel time t of the reflected wave from the abnormal point reaching the detector n, obtain the time point serial number of the abnormal point in the waveform received by the detector n, and extract the elastic wave sampling value of the corresponding time point serial number of the detector n, and reconstruct the elastic wave signal at any depth with the detector n as the anchor point under the Mi position, including: The travel time t of the reflected waveform of the abnormal point at the depth h under the Mi position between the right side of the shot point and any detector n position with an offset of x reaching the detector is: where: t is the travel time of the reflected wave; d is the distance between the Mi position and the detector; β is the angle between the line connecting the abnormal point and the detector and the horizontal plane; v is the elastic wave velocity.

[0019] Reconstruct the elastic wave signals at all positions in the detection area, and perform waveform superposition processing on the reconstructed signals to obtain the superimposed signal, including: The elastic wave signals at all positions in the detection area p ( x , t ) are reconstructed, and waveform superposition processing is performed on the reconstructed signals to obtain the superimposed signal P 叠加 ( t ) = ∑ p ( x i , t ), i = 1, 2, …, n.

[0020] Use focused imaging to image the superimposed signal to identify the abnormal bodies inside the large-volume hydraulic concrete, including: The imaging process is expressed as: I ( x , y , z ) = F{ P 叠加 ( t )} where, I ( x , y , z ) represents the intensity distribution in the imaging space, F represents the focused imaging algorithm, and converts the time-domain signal P 叠加 ( t ) into a spatial-domain image, so as to identify the abnormal bodies inside the concrete D .

[0021] A detection and imaging system for abnormal bodies inside large-volume hydraulic concrete, corresponding to the detection and imaging method for abnormal bodies inside large-volume hydraulic concrete, includes: an elastic wave acquisition module, a data processing module, and an imaging module; the imaging module and the elastic wave acquisition module are respectively connected to the data processing module; The elastic wave acquisition module is used to perform single-sided common shot point array percussion scanning sampling; The data processing module is used to perform amplitude gain compensation, time difference correction, signal reconstruction, and waveform superposition processing on the acquired elastic wave data; The imaging module uses focusing imaging technology to image the processed signal and generate an image of the abnormal body inside the concrete.

[0022] The elastic wave acquisition module includes a hammering seismic source module and an array geophone module, and the hammering seismic source module and the array geophone module are respectively connected to the data processing module.

[0023] It further includes a time difference correction unit, the time difference correction unit is connected to the data processing module, and the time difference correction unit performs precise time correction on the elastic wave signal according to a preset travel time formula.

[0024] The imaging module includes a focusing imaging unit and an anomaly recognition module, and the focusing imaging unit and the anomaly recognition module are respectively connected to the data processing module.

[0025] Specifically, the on-site elastic wave data acquisition method is single-sided common shot point array percussion scanning sampling, as Figure 3 shown. Specifically: a single-sided hammering seismic source is adopted, geophones are arranged in an array at equal distances on one side of the seismic source, and signals are received simultaneously. The hammering seismic source rolls and hammers along the arrangement direction and position of the geophones, and subsequent sensors successively receive signals until the (n - 1)-th hammering point is hammered.

[0026] Perform amplitude gain compensation and time difference correction processing on the acquired elastic wave data. According to the system for collecting elastic waves by single-sided common shot point rolling excitation adopted in the present invention, a special time difference correction method is adopted to reconstruct the elastic wave signal.

[0027] Between the right side of the shot point and any geophone n position with an offset of x, the travel time formula for the reflected waveform of the abnormal point at a depth h under the Mi position to reach the geophone is: By obtaining the time \(t\) when the reflected wave of the abnormal point reaches the detector \(n\), the time point sequence number of the waveform received by the detector \(n\) at the abnormal point can be calculated. By extracting the elastic wave sampling values of the corresponding time point sequence number of the detector \(n\), the elastic wave signals at any depth with the detector \(n\) as the anchor point under the \(M_i\) position are reconstructed.

[0028] Using the above method, the elastic wave signals at any position in the detection area are reconstructed and waveform superposition processing is performed. The focused imaging method is used to image the reconstructed signals. As Figure 4 shown, it is a schematic diagram before and after reconstruction. (a) is the imaging schematic diagram before calibration processing; (b) is the imaging schematic diagram after reconstruction processing.

[0029] The above is only the preferred embodiment of the present invention. It should be understood that the present invention is not limited to the form disclosed herein, should not be regarded as excluding other embodiments, but can be used in various other combinations, modifications and environments, and can be changed within the scope of the concept described herein through the above teachings or the technology or knowledge in related fields. And the changes and variations made by those skilled in the art that do not depart from the spirit and scope of the present invention should all be within the protection scope of the appended claims of the present invention.

Claims

1. A method for detecting and imaging abnormal bodies inside large-volume concrete of hydraulic structures, characterized in that: The following steps are involved: Step 1: Acquire elastic wave data on site by using a single-sided common shot point array-type percussion scanning sampling method. By using a single-sided hammer source, array-type equidistantly arranged geophones are arranged on one side of the source to simultaneously receive signals. The hammer source rolls and hammers along the arrangement direction and position of the geophones until the n-1th hammer point is hammered. Step 2: Perform amplitude gain compensation and time difference correction processing on the collected elastic wave data, reconstruct the elastic wave signal through time difference correction, and obtain the abnormal point reflection wave; Step 3: According to the travel time t of the reflected wave from the abnormal point to the detector n, the time point number of the abnormal point when the waveform is received by the detector n is obtained, and the elastic wave sampling value of the corresponding time point number of the detector n is extracted to reconstruct the elastic wave signal of any depth with the detector n as the anchor point under the point Mi; Step 4, reconstructing the elastic wave signals at all positions in the detection area, and performing waveform superposition processing on the reconstructed signals to obtain superimposed signals; Step five, use focused imaging to image the superimposed signals, and identify abnormal bodies inside the hydraulic mass concrete based on the imaging results.

2. The method for detecting and imaging abnormal bodies inside hydraulic mass concrete according to claim 1 is characterized in that: The aforementioned processing of amplitude gain compensation and time difference correction on the collected elastic wave data, reconstructing the elastic wave signal through time difference correction, and obtaining the abnormal point reflection wave includes: The amplitude gain compensation is: A compensated = A original × G in A compensated is the amplitude after compensation, A original is the original amplitude, G is the gain coefficient; The time difference correction is: t corrected = t measured −D t in t corrected is the corrected time, t measured is the measurement time, Δ t For time difference; To reconstruct the elastic wave signal, the following formula is used: p ( x , t )= P sin( kx − ωt + ϕ ) in: P is the amplitude, k = is the wave number, λ is the wavelength; ω =2 πf is the angular frequency, f is the frequency; ϕ is the initial phase, which indicates the phase of the wave at the initial moment.

3. The method for detecting and imaging abnormal bodies inside hydraulic mass concrete according to claim 2 is characterized in that: The method of obtaining the time point sequence number of the abnormal point when the waveform is received by the detector n according to the travel time t of the reflected wave from the abnormal point to the detector n, extracting the elastic wave sampling value of the corresponding time point sequence number of the detector n, and reconstructing the elastic wave signal of any depth with the detector n as the anchor point at the point Mi includes: The travel time t of the reflected waveform from the abnormal point at depth h at position Mi between the right side of the shot point and any geophone point n with an offset distance of x to the geophone is: Among them: t is the travel time of the reflected wave; d is the distance from the Mi position to the detector; β is the angle between the line from the abnormal point to the detector and the horizontal plane; v is the elastic wave velocity.

4. The method for detecting and imaging abnormal bodies inside hydraulic mass concrete according to claim 3 is characterized in that: The reconstructing of elastic wave signals at all positions in the detection area and performing waveform superposition processing on the reconstructed signals to obtain superimposed signals includes: Elastic wave signals at all locations in the detection area p ( x , t ) is used to reconstruct the signal, and the reconstructed signal is processed by waveform superposition to obtain the superimposed signal P 叠加 ( t ) =∑ p ( x i , t ), i=1,2,…,n.

5. The method for detecting and imaging abnormal bodies inside hydraulic mass concrete according to claim 1 is characterized in that: The method of using focused imaging to image the superimposed signals and identify abnormal bodies inside the hydraulic mass concrete includes: The imaging process is expressed as: I ( x , y , z )=F{ P 叠加 ( t )} in, I ( x , y , z ) represents the intensity distribution in the imaging space, F represents the focusing imaging algorithm, and the time domain signal P 叠加 ( t ) is converted into a spatial domain image to identify abnormal bodies inside the concrete D .

6. A system for detecting abnormal bodies inside large-volume concrete of hydraulic structures, characterized in that: A method for detecting and imaging abnormal bodies inside a hydraulic mass concrete according to any one of claims 1 to 5 comprises: an elastic wave acquisition module, a data processing module and an imaging module; the imaging module and the elastic wave acquisition module are respectively connected to the data processing module; The elastic wave acquisition module is used to perform single-side common shot point array tapping scanning sampling; The data processing module is used to perform amplitude gain compensation, time difference correction, signal reconstruction and waveform superposition processing on the collected elastic wave data; The imaging module uses a focusing imaging technique to image the processed signal and generate an image of the abnormal body inside the concrete.

7. The imaging system for detecting abnormal bodies inside hydraulic mass concrete according to claim 6 is characterized in that: The elastic wave acquisition module includes a hammer source module and an array detector module, and the hammer source module and the array detector module are respectively connected to the data processing module.

8. The imaging system for detecting abnormal bodies inside hydraulic mass concrete according to claim 6 is characterized in that: It also includes a time difference correction unit, which is connected to the data processing module and performs accurate time correction on the elastic wave signal according to a preset travel time formula.

9. The imaging system for detecting abnormal bodies inside hydraulic mass concrete according to claim 6 is characterized in that: The imaging module comprises a focusing imaging unit and an abnormality recognition module, and the focusing imaging unit and the abnormality recognition module are respectively connected to the data processing module.

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