A nondestructive testing method, device and system for bridge pile foundation

Abstract

The present invention relates to the technical field of bridge pile testing, and more specifically, to a method, device, and system for nondestructive testing of bridge pile foundations. This method uses peak characteristics of reflected wave signals to identify target signal bands within the pile foundation. Then, by combining peak shape characteristics of different signal sources and the corresponding moments of the peaks, matching peak association groups are identified. Subsequently, based on a temporal analysis of the peak association groups, peaks at the steel-concrete interface are further screened out to obtain analysis bands. The stability index of the pile foundation is determined based on the peak states of the analysis bands at different heights. This method effectively identifies the influence of the steel-concrete interface on stability analysis, improving the reliability and accuracy of the internal stability analysis of the pile foundation.

Description

Technical Field

[0001] The present invention relates to the technical field of bridge pile detection, and in particular to a bridge pile foundation non-destructive detection method, device and system. Background Art

[0002] Bridge pile foundations are a crucial component of bridge engineering, typically supporting the bridge's superstructure and ensuring its stability under various loads. Piles transfer loads to deeper, more stable soil or rock layers, protecting the bridge from adverse factors such as subsidence, slippage, or overturning. Nondestructive testing (NDT) technology is a crucial tool for quality control of bridge pile foundations. It can provide real-time insights into the structural status without impacting operational performance, providing strong support for bridge design, construction, and maintenance.

[0003] Currently, nondestructive testing of bridge pile foundations typically uses the propagation characteristics of sound waves within the pile foundation to detect defects by analyzing the reflection and attenuation characteristics of the signal waveform. However, the heterogeneity of the material within the pile foundation (for example, the interface between the steel bars and concrete in the pile foundation) can also reflect the sound wave signal. The peak shape characteristics of these reflected waves can be very similar to the peak shape of the reflected wave of the defect, thus affecting the accuracy of identifying defects such as holes and cracks within the pile foundation, resulting in insufficient reliability and accuracy in the analysis of the internal stability of the pile foundation. Summary of the Invention

[0004] In order to solve the technical problem in the related art that the waveform of the contact surface between the steel bar and concrete in the pile foundation is very similar to the reflection wave peak shape of the defect, thereby affecting the identification of defects such as holes and cracks in the pile foundation, resulting in insufficient reliability and accuracy in the internal stability analysis of the pile foundation, the present invention provides a bridge pile foundation non-destructive testing method, device and system. The technical solutions adopted are as follows:

[0005] The present invention proposes a non-destructive testing method for bridge pile foundations, wherein multiple signal sources are set at different heights of the pile foundation. The method comprises:

[0006] Obtain the reflected wave signal collected by each signal source and passing through the pile foundation; determine the different peaks of the reflected wave signal;

[0007] The peak shape characteristic factor of the peak is determined based on the signal intensity and peak width at any peak, as well as the time interval between the peak and the next peak. The peak shape characteristic factors of all peaks are clustered to obtain the target signal band inside the pile foundation.

[0008] Determining the matching degree of two peaks based on peak shape characteristic factors and corresponding moments of peaks in different signal source and target signal bands; screening and obtaining matching peaks based on the matching degree to form a peak association group;

[0009] Determine the target peak of the steel-concrete contact surface based on the attenuation of the signal strength of the peak association group and the temporally adjacent association groups; and use the remaining bands of the target signal band except the band where the target peak is located as analysis bands;

[0010] The stability index of the pile foundation is determined based on the peak state of the analysis band at different heights.

[0011] Furthermore, determining the peak shape characteristic factor of the peak based on the signal strength and peak width at any peak, and the time interval between the peak and the next peak, includes:

[0012] The time interval between the closest troughs on both sides of the signal waveform is taken as the peak width;

[0013] The ratio of the peak signal intensity at the peak position to the peak width is used as the first characteristic index;

[0014] The time interval between the next peak in the time series is used as the second characteristic index, wherein the second characteristic index of the last peak is a preset value of 1;

[0015] The ratio of the first characteristic index to the second characteristic index is calculated and normalized to be the peak shape characteristic factor.

[0016] Furthermore, clustering is performed based on the peak shape characteristic factors of all peaks to obtain the target signal band inside the pile foundation, including:

[0017] Clustering is performed based on the value of the peak characteristic factor. The number of clusters is set to 3, and the clusters before entering the pile foundation, the clusters inside the pile foundation, and the clusters after passing through the pile foundation are obtained.

[0018] The signal band corresponding to the cluster inside the pile foundation is used as the target signal band.

[0019] Furthermore, the matching degree of the two peaks is determined based on the peak shape characteristic factors between the peaks of the target signal bands of different signal sources and the corresponding moments of the peaks, including:

[0020] The time interval between the corresponding moments of two wave peaks of different signal sources is used as the first matching index;

[0021] The absolute value of the difference between the peak shape characteristic factors corresponding to two peaks of different signal sources is used as the second matching index;

[0022] The product value of the first matching index and the second matching index is calculated, and the inverse of the product value is normalized to obtain the result as the matching degree of the two peaks.

[0023] Furthermore, matching peaks are screened and obtained according to the matching degree to form a peak association group, including:

[0024] The peaks with matching degrees greater than 0.75 in different signal sources are taken as a peak association group.

[0025] Furthermore, determining a target peak of the steel-concrete contact surface according to the attenuation of the signal strength between the peak association group and the temporally adjacent association group includes:

[0026] Determine the mean value of the signal intensities of all peaks in any peak association group as the peak coefficient of the corresponding peak association group;

[0027] The peak correlation group that is closest to the previous one in the time sequence of any peak correlation group is regarded as the previous correlation group, and the peak correlation group that is closest to the next one in the time sequence is regarded as the next correlation group;

[0028] Calculating the difference between the peak coefficients of the peak correlation group and the previous correlation group as the first correlation index; calculating the difference between the peak coefficients of the subsequent correlation group and the peak correlation group as the second correlation index;

[0029] determining, according to the first correlation index and the second correlation index, whether the peak correlation group satisfies a decreasing trend;

[0030] The peak association group that does not satisfy the decreasing trend is used as the target association group, and the corresponding peak in the target association group is the target peak.

[0031] Further, determining whether the peak association group satisfies a decreasing trend according to the first association index and the second association index includes:

[0032] When both the first correlation index and the second correlation index are negative, it is determined that the peak correlation group satisfies a decreasing trend; otherwise, it is determined that the peak correlation group does not satisfy a decreasing trend.

[0033] Furthermore, according to the peak state of the analysis band at different heights, the stability index of the pile foundation is determined, including:

[0034] Calculate the product of the signal strength corresponding to the peak and the peak width as the waveform abnormality index of the corresponding peak;

[0035] The average value of the waveform anomaly index of all peaks in the analysis band corresponding to any signal source is used as the first height anomaly index;

[0036] Calculate the mean of the number of peaks in the analysis bands of all signal sources, and use the ratio of the number of peaks of any signal source to the mean as the second height anomaly indicator;

[0037] Normalizing the product of the first height abnormality index and the second height abnormality index to obtain a defect abnormality factor corresponding to the height of the signal source;

[0038] The sum of the defect anomaly factors at the heights of all signal sources is calculated, and the opposite of the sum is normalized as the stability index of the pile foundation.

[0039] On the other hand, a non-destructive testing device for bridge pile foundations is also provided, which includes a memory, a processor, and a computer program stored in the memory and running on the processor. When the processor executes the computer program, the steps of any of the methods described above are implemented.

[0040] On the other hand, a nondestructive testing system for bridge pile foundations is provided, wherein multiple signal sources are provided at different heights of the pile foundations, and the system comprises:

[0041] An acquisition module is used to acquire the reflected wave signal collected by each signal source and passing through the pile foundation; and to determine different peaks of the reflected wave signal;

[0042] The pile foundation internal analysis module is used to determine the peak shape characteristic factor of the peak based on the signal strength and peak width at any peak, as well as the time interval between the peak and the next peak; clustering is performed based on the peak shape characteristic factors of all peaks to obtain the target signal band inside the pile foundation;

[0043] The correlation analysis module is used to determine the matching degree of two peaks based on the peak shape characteristic factors and the corresponding moments of the peaks of the target signal bands of different signal sources; and to screen the matching peaks according to the matching degree to form a peak correlation group;

[0044] A steel bar surface analysis module is used to determine the target peak of the steel bar-concrete contact surface based on the attenuation of the signal strength of the peak association group and the temporally adjacent association groups; and the remaining bands of the target signal band except the band where the target peak is located are used as analysis bands;

[0045] The stability analysis module is used to determine the stability index of the pile foundation based on the peak state of the analysis band at different heights.

[0046] The present invention has the following beneficial effects:

[0047] In an embodiment of the present invention, the target signal band within the pile foundation is obtained by screening the peak characteristics of the reflected wave signal. Then, by combining the peak shape characteristic factors of different signal sources and the corresponding moments of the peaks, a matching peak association group is screened. Subsequently, based on the analysis of the peak association group in time sequence, the peaks of the steel-concrete contact surface are further screened to obtain an analysis band. The stability index of the pile foundation is determined based on the peak state of the analysis band at different heights. This solves the problem of inaccurate identification of defects such as holes and cracks within the pile foundation due to the similarity between the waveform characteristics of the reflected wave signal generated by the heterogeneity of the internal material of the pile foundation and the reflected waveform of the defect. This effectively screens the influence of the steel-concrete contact surface on the stability analysis, and improves the reliability and accuracy of the internal stability analysis of the pile foundation. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] In order to more clearly illustrate the technical solutions and advantages of the embodiments of the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the prior art descriptions. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0049] Figure 1 A schematic diagram of a pile foundation nondestructive testing scenario provided by one embodiment of the present invention;

[0050] Figure 2 A flow chart of a non-destructive testing method for bridge pile foundations provided by one embodiment of the present invention;

[0051] Figure 3 A schematic diagram of a target signal band provided by an embodiment of the present invention;

[0052] Figure 4 A schematic diagram of a peak association group provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0053] To further illustrate the technical means and effectiveness of the present invention in achieving its intended purpose, the following, in conjunction with the accompanying drawings and preferred embodiments, describes in detail the specific implementation, structure, features, and effectiveness of a bridge pile foundation nondestructive testing method, device, and system proposed in accordance with the present invention. In the following description, references to different "one embodiment" or "another embodiment" do not necessarily refer to the same embodiment. Furthermore, specific features, structures, or characteristics of one or more embodiments may be combined in any suitable manner.

[0054] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

[0055] The specific scheme of the bridge pile foundation non-destructive testing method provided by the present invention is described in detail below with reference to the accompanying drawings.

[0056] See also Figure 1 and Figure 2 , Figure 1 This is a schematic diagram of a nondestructive testing scenario for a pile foundation provided by an embodiment of the present invention. Multiple signal sources are set at different heights of the pile foundation, and the signal sources are mainly acoustic signal probes. Figure 2 A flow chart of a nondestructive testing method for bridge pile foundations provided in one embodiment of the present invention includes:

[0057] S101: Acquire the reflected wave signal collected by each signal source and passing through the pile foundation; determine different peaks of the reflected wave signal.

[0058] In the embodiment of the present invention, an acoustic wave signal is emitted toward the pile foundation by an acoustic wave signal probe, and reflected by the pile foundation to obtain a reflected wave signal. Figure 1 For a detailed analysis, multiple ultrasonic probes, evenly arranged longitudinally, transmit signals at different heights of the pile foundation, receive reflected wave signals, and use bandpass filtering to remove noise. It is necessary to ensure that the signals emitted by all probes cover the entire pile foundation area and that each probe's transmitting end is at the same angle and distance from the pile foundation. Furthermore, since the pile foundation consists of above-ground and underground sections, for the underground section, a hole is drilled in the ground near the pile foundation, inserting an acoustic testing tube. Ultrasonic probes are then connected and placed into the tube for testing. Subsequent waveform analysis is performed based on the reflected wave signals at different locations.

[0059] During the specific waveform analysis process, since interference will occur at the contact surface between concrete and steel bars, and the waveform in the non-pile foundation area will also cause interference, it is necessary to analyze the peak changes of the reflected wave signal in order to analyze these interference effects. Therefore, in the embodiment of the present invention, the peak characteristics collected by each signal source are statistically analyzed.

[0060] S102: Determine the peak shape characteristic factor of the peak based on the signal strength and peak width at any peak, as well as the time interval between the peak and the next peak; cluster the peak shape characteristic factors of all peaks to obtain the target signal band inside the pile foundation.

[0061] Since the ultrasonic probe at each signal source transmits ultrasonic signals and receives reflected wave signals, each reflected wave signal reflects the internal quality of the pile foundation at different cross-sectional heights. Therefore, the stability of the pile foundation can be measured by combining the waveform characteristics of the reflected wave signals at different heights.

[0062] However, during the lateral measurement process of this embodiment, there is no direct contact between the probe and the pile foundation. There are other media (soil, air) in between, and the resulting reflected wave contains the characteristics of these non-related areas. However, to detect the stability of the pile foundation, it is only necessary to consider the reflected wave signal of the sound wave passing through the internal area of ​​the pile foundation. Therefore, this step first determines the target signal band of the internal area of ​​the pile foundation based on the reflected wave signal.

[0063] Generally, when ultrasonic waves propagate in the soil, the wave crest is wide and the time delay is long. However, after entering the pile foundation, the wave speed increases, the wave crest time shortens, and the waveform may become sharper. At the same time, the waveform in the soil is relatively flat, while the waveform in the pile foundation is relatively concentrated. Figure 3 , Figure 3 This is a schematic diagram of the target signal band provided by one embodiment of the present invention. Therefore, the peak shape characteristic factor can be determined by combining the signal strength and peak width at the peak, as well as the time interval between the peak and the next peak. The target signal band within the pile foundation area can then be determined based on the peak shape characteristic factor.

[0064] Furthermore, in some embodiments of the present invention, the peak shape characteristic factor of the peak is determined based on the signal strength and peak width at any peak, as well as the time interval between the peak and the subsequent peak, including: taking the time interval between the troughs closest to the peak on both sides of the signal waveform as the peak width; taking the ratio of the peak signal strength at the peak position to the peak width as the first characteristic indicator; taking the time interval between the subsequent peak in the time sequence as the second characteristic indicator, wherein the second characteristic indicator of the last peak is a preset value of 1; calculating the ratio of the first characteristic indicator and the second characteristic indicator, and normalizing it as the peak shape characteristic factor.

[0065] Among them, the peak width is the time interval from the previous trough position to the next trough position, which represents the "sharp" feature of the peak itself. After entering the pile foundation, the wave speed accelerates, the peak time shortens, and the waveform may become more "sharp", that is, the smaller the peak width, the more likely it is the waveform inside the pile foundation. Similarly, the greater the peak signal intensity at the peak position, the more likely it is the waveform inside the pile foundation.

[0066] Therefore, the ratio of the peak signal intensity at the peak position to the peak width is directly calculated as the first characteristic index. The larger the value of the first characteristic index, the higher the corresponding peak and the sharper the waveform.

[0067] The waveforms in media like soil and air are relatively flat, while the waveforms in pile foundations are more concentrated. The fluctuations within the pile foundation are characterized by intense fluctuations, and the distances between peaks become shorter. Therefore, the time interval between subsequent peaks in the time series is used as the second characteristic index. The smaller the value of the second characteristic index, the more consistent it is with the waveform characteristics within the pile foundation. From this, the ratio of the first characteristic index to the second characteristic index is directly calculated and normalized to form the peak shape characteristic factor, enabling analysis of waveform characteristics.

[0068] Since ultrasonic signals present different peak characteristics in different media, the characteristic factor corresponding to the pile foundation is larger, while the characteristic factor before entering the pile foundation or after passing through the pile foundation is smaller. Therefore, a clustering method can be used to cluster the peaks based on the size of the characteristic factors corresponding to different peaks.

[0069] Furthermore, in some embodiments of the present invention, clustering is performed according to the peak shape characteristic factors of all peaks to obtain the target signal band inside the pile foundation, including: clustering based on the numerical value of the peak characteristic factor, setting the number of clusters to 3, obtaining the cluster before entering the pile foundation, the cluster inside the pile foundation, and the cluster after passing through the pile foundation; and taking the signal band corresponding to the cluster inside the pile foundation as the target signal band.

[0070] The clustering method in the embodiment of the present invention can be specifically, for example, k-means clustering, thereby classifying the signal bands corresponding to adjacent peaks with similar characteristics as one class. Then, according to the actual scenario, the three clusters are divided into a cluster before entering the pile foundation, a cluster inside the pile foundation, and a cluster after passing through the pile foundation. In the signal band, the signal band corresponding to the middle cluster is used as the target signal band. Alternatively, the mean of the peak characteristic factor can be calculated, and the signal band corresponding to the cluster with the largest mean value of the peak characteristic factor is used as the target signal band.

[0071] It can be understood that in the process of dividing the signal band of a specific cluster, the trough can be used as the dividing point, that is, the dividing point between the cluster before entering the pile foundation and the cluster inside the pile foundation is at the trough position between the corresponding two peaks, thereby realizing the division of the target signal band.

[0072] S103: determining the matching degree of two peaks based on the peak shape characteristic factors and the corresponding moments of the peaks of the target signal bands of different signal sources; and screening the matching peaks to form a peak association group based on the matching degree.

[0073] The above method can be used to obtain the corresponding target signal band for the signal reflection wave at any height position of the pile foundation. However, since there is at least one steel bar cast in the pile foundation, the peak shape characteristics of the reflection wave signal of the steel bar-concrete contact surface may be similar to the reflection peak shape of the defect. Therefore, it is necessary to screen the different peaks based on the target band to exclude the peaks corresponding to the possible steel bar-concrete contact surface and improve the accuracy of defect signal identification.

[0074] Since the distribution of steel bars at different heights is relatively similar, feature matching of steel bars at different heights can be achieved. Specifically, a matching degree analysis is required to screen out peak correlation groups.

[0075] Furthermore, in some embodiments of the present invention, the degree of matching between two peaks is determined based on the peak shape characteristic factors between the peaks of target signal bands of different signal sources and the moments corresponding to the peaks, including: taking the time interval between the moments corresponding to the two peaks of different signal sources as the first matching index; taking the absolute value of the difference between the peak shape characteristic factors corresponding to the two peaks of different signal sources as the second matching index; calculating the product value of the first matching index and the second matching index, and normalizing the opposite of the product value as the degree of matching between the two peaks.

[0076] Since the signal source collects reflected wave signals at the same frequency at the same time, after encountering the upright steel bars, the corresponding waveform changes should also be at the same moment. The time interval between the corresponding moments of the two peaks of different signal sources is used as the first matching index. The smaller the value of the first matching index, the more likely the corresponding two peaks are to represent the same steel bar waveform characteristics.

[0077] The absolute value of the difference between the peak shape characteristic factors corresponding to two peaks of different signal sources is used as the second matching index. The smaller the value of the second matching index is, the closer the values ​​of the peak shape characteristic factors are.

[0078] In summary, the product of the first and second matching indices is calculated, and the inverse of the product is normalized to obtain the degree of matching between the two peaks. Normalization in the embodiments of the present invention involves mapping the result to the interval [0, 1], specifically by linear mapping, such as maximum-minimum normalization, or by using other linear normalization algorithms, without limitation.

[0079] The greater the matching degree between two peaks, the closer the two peaks are and the more similar the peaks are in shape, thus determining a peak association group. Peaks that match are screened based on the matching degree to form a peak association group, including: peaks with a matching degree greater than 0.75 from different signal sources as one peak association group.

[0080] See also Figure 4 , Figure 4This is a schematic diagram of a peak association group provided by one embodiment of the present invention. Two peaks in the figure share similar characteristics, indicating that they share the same scene information. Each frame in the figure contains peaks belonging to different target signal bands, forming a peak association group. Since the above results are based solely on the longitudinal similarity of peaks, it cannot be assumed that all of these peaks correspond to contact surfaces. Screening is also required based on the characteristics of contact surface peaks within the same signal band.

[0081] S104: Determine the target peak of the steel-concrete contact surface based on the attenuation of the signal strength between the peak association group and the temporally adjacent association groups; and use the remaining bands of the target signal band except the band where the target peak is located as analysis bands.

[0082] For a certain signal source, its sound wave signal will pass through each steel bar-concrete contact surface after entering the pile foundation. Since different steel bars are at different distances from the signal source transmitting end, the corresponding signal attenuation will be different. That is, the farther the steel bar is from the signal source transmitting end, the greater the signal attenuation reflected by the steel bar is, and the corresponding peak intensity is lower.

[0083] Therefore, the intensity of each contact surface peak from left to right in the band will show a gradually decreasing trend. Then, the attenuation characteristics of the peak intensity of each adjacent peak association group from left to right can be compared to screen out the target peak of the steel bar-concrete contact surface.

[0084] Furthermore, in some embodiments of the present invention, the target peak of the steel bar-concrete contact surface is determined based on the attenuation of signal strength between the peak association group and the adjacent association group in time sequence, including: determining the mean value of the signal strength of all peaks in any peak association group as the peak coefficient of the corresponding peak association group; taking the peak association group that is closest to the previous peak association group in time sequence of any peak association group as the front association group, and the peak association group that is closest to the next peak association group in time sequence as the back association group; calculating the difference between the peak coefficients of the peak association group and the front association group as the first association index; calculating the difference between the peak coefficients of the back association group and the peak association group as the second association index; determining whether the peak association group satisfies the decreasing trend based on the first association index and the second association index; taking the peak association group that does not satisfy the decreasing trend as the target association group, and the corresponding peak in the target association group as the target peak.

[0085] When analyzing the peak association group, it is necessary to determine the overall characteristic parameters of the peak association group. In the embodiment of the present invention, the peak coefficient is obtained as the characteristic parameter of the peak association group by calculating the mean of the signal strength of all peaks in any peak association group, thereby realizing the characteristic analysis of the peak association group.

[0086] To perform attenuation analysis, you need to set the front and back relationships. The peak correlation group closest to the preceding peak correlation group in the timing sequence is considered the front correlation group, and the peak correlation group closest to the following peak correlation group is considered the following peak correlation group. Since peaks exhibit timing characteristics on the signal curve, the peak correlation group closest to the preceding peak correlation group is considered the front correlation group, and the peak correlation group closest to the following peak correlation group is considered the following peak correlation group.

[0087] Furthermore, in some embodiments of the present invention, whether the peak association group satisfies the decreasing trend is determined based on the first association indicator and the second association indicator, including: when the first association indicator and the second association indicator are both negative, determining that the peak association group satisfies the decreasing trend; otherwise, determining that the peak association group does not satisfy the decreasing trend.

[0088] It can be understood that, in the corresponding attenuation conditions in the scenario, the signal strength of the front association group is greater than that of the analyzed peak association group, which in turn is greater than that of the rear association group. When the attenuation characteristic is met, the analyzed peak association group can be determined to be the target association group for a normal steel-concrete contact surface, and the peak in the target association group is the target peak. Therefore, in this embodiment of the present invention, by determining the first and second association indicators, the attenuation characteristic is met only when both the first and second association indicators are negative, thereby accurately acquiring the target peak.

[0089] After determining the target peak of the steel-concrete contact surface, in order to avoid the influence of the target peak on the defect analysis, the remaining bands in the target signal band except the band where the target peak is located are used as analysis bands.

[0090] S105: Determine the stability index of the pile foundation based on the peak state of the analysis band at different heights.

[0091] Due to the vertical arrangement of the signal sources in this embodiment, the band corresponding to each signal source can only reflect the defects at the corresponding height of the pile foundation it covers. If the defects of the entire pile foundation are to be evaluated and then stability analysis is to be performed, a comprehensive evaluation must be conducted in combination with all signal sources.

[0092] Furthermore, in some embodiments of the present invention, the stability index of the pile foundation is determined according to the peak state of the analysis band at different heights, including: calculating the product of the signal strength corresponding to the peak and the peak width as the waveform anomaly index of the corresponding peak; taking the average of the waveform anomaly indexes of all peaks in the analysis band corresponding to any signal source as the first height anomaly index; calculating the average of the number of peaks in the analysis band of all signal sources, and taking the ratio of the number of peaks of any signal source to the average as the second height anomaly index; normalizing the product of the first height anomaly index and the second height anomaly index as the defect anomaly factor of the height corresponding to the signal source; calculating the sum of the defect anomaly factors at the height of all signal sources, and normalizing the inverse of the sum as the stability index of the pile foundation.

[0093] If there are defects (holes, cracks) at a certain position of the pile foundation, these will cause multiple reflections and scattering of the sound waves, resulting in a superposition state, resulting in more dense and high-intensity wave peaks. At the same time, the defects may cause the propagation speed of the sound waves to change, and the duration of the wave peaks will also be longer.

[0094] That is to say, since the existence of defects will make the peaks more dense, the larger the peak scale, the abnormal peak has the characteristics of higher signal intensity and larger peak width. Therefore, in the embodiment of the present invention, the product value of the signal intensity and peak width corresponding to the peak is calculated as the waveform abnormality index of the corresponding peak; the average value of the waveform abnormality index of all peaks in the analysis band corresponding to any signal source is used as the first height abnormality index, and the first height abnormality index characterizes the abnormal characteristics of the signal source at the corresponding height.

[0095] Then, the mean of the number of peaks in the analysis bands of all signal sources is calculated, and the ratio of the number of peaks of any signal source to the mean is used as the second height anomaly index. The second height anomaly index represents the peak density characteristics in the corresponding band. The greater the density, the more abnormal it is.

[0096] In summary, the product value of the first height anomaly index and the second height anomaly index is normalized as the defect anomaly factor corresponding to the height of the signal source. The defect anomaly factors of all heights are fused, negatively correlated and normalized to serve as the stability index of the pile foundation.

[0097] The above method can be used to more accurately detect the stability of the pile foundation. Since the pile foundation is only the foundation for bridge construction, if the stability assessment finds that the pile foundation is unstable or has insufficient bearing capacity, on-site drilling sampling should be carried out in a timely manner to verify and adjust the overall design plan (increasing the number of piles, deepening the pile foundation, etc.).

[0098] At the same time, a long-term monitoring system should be established based on soil conditions, and pile foundations should be regularly inspected for settlement, tilt, cracks, and other conditions after bridge construction. Especially for bridges located in areas with complex geological conditions or active earthquakes, the use of sensors, settlement meters, accelerometers, and other equipment should be increased to monitor the health of pile foundations in real time.

[0099] In an embodiment of the present invention, the target signal band within the pile foundation is obtained by screening the peak characteristics of the reflected wave signal. Then, by combining the peak shape characteristic factors of different signal sources and the corresponding moments of the peaks, a matching peak association group is screened. Subsequently, based on the analysis of the peak association group in time sequence, the peaks of the steel-concrete contact surface are further screened to obtain an analysis band. The stability index of the pile foundation is determined based on the peak state of the analysis band at different heights. This solves the problem of inaccurate identification of defects such as holes and cracks within the pile foundation due to the similarity between the waveform characteristics of the reflected wave signal generated by the heterogeneity of the internal material of the pile foundation and the reflected waveform of the defect. This effectively screens the influence of the steel-concrete contact surface on the stability analysis, and improves the reliability and accuracy of the internal stability analysis of the pile foundation.

[0100] In other embodiments of the present invention, a non-destructive testing device for bridge pile foundations is also provided. The device includes a memory, a processor, and a computer program stored in the memory and running on the processor. When the processor executes the computer program, the steps of any one of the aforementioned non-destructive testing methods for bridge pile foundations are implemented.

[0101] In another embodiment of the present invention, a nondestructive testing system for bridge pile foundations is provided, wherein multiple signal sources are provided at different heights of the pile foundations, and the system includes:

[0102] An acquisition module is used to acquire the reflected wave signal collected by each signal source and passing through the pile foundation; and to determine different peaks of the reflected wave signal;

[0103] The pile foundation internal analysis module is used to determine the peak shape characteristic factor of the peak based on the signal strength and peak width at any peak, as well as the time interval between the peak and the next peak; clustering is performed based on the peak shape characteristic factors of all peaks to obtain the target signal band inside the pile foundation;

[0104] The correlation analysis module is used to determine the matching degree of two peaks based on the peak shape characteristic factors and the corresponding moments of the peaks of different signal source and target signal bands; and to screen the matching peaks according to the matching degree to form a peak correlation group;

[0105] The steel bar surface analysis module is used to determine the target peak of the steel bar-concrete contact surface based on the attenuation of the signal strength of the peak correlation group and the adjacent correlation groups in time sequence; the remaining bands of the target signal band except the band where the target peak is located are used as analysis bands;

[0106] The stability analysis module is used to determine the stability index of the pile foundation based on the peak state of the analysis band at different heights.

[0107] The specific implementation of a bridge pile foundation nondestructive testing system is similar to any of the steps of the aforementioned bridge pile foundation nondestructive testing method. The technical effects of a bridge pile foundation nondestructive testing system and a bridge pile foundation nondestructive testing device are the same as those of the bridge pile foundation nondestructive testing method, and will not be further described.

[0108] It should be noted that the order in which the embodiments of the present invention are described above is for illustrative purposes only and does not necessarily represent the superiority or inferiority of the embodiments. The processes depicted in the accompanying drawings do not necessarily require the specific order or sequential order shown to achieve the desired results. In certain embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0109] The various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on the differences from other embodiments.

Claims

1. A non-destructive testing method for bridge pile foundation, characterized in that: A plurality of signal sources are arranged at different heights of the pile foundation, and the method comprises: Obtain the reflected wave signal collected by each signal source and passing through the pile foundation; determine the different peaks of the reflected wave signal; The peak shape characteristic factor of the peak is determined based on the signal intensity and peak width at any peak, as well as the time interval between the peak and the next peak. The peak shape characteristic factors of all peaks are clustered to obtain the target signal band inside the pile foundation. Determining the matching degree of two peaks based on peak shape characteristic factors and corresponding moments of peaks in different signal source and target signal bands; screening and obtaining matching peaks based on the matching degree to form a peak association group; Determine the target peak of the steel-concrete contact surface based on the attenuation of the signal strength of the peak association group and the temporally adjacent association groups; and use the remaining bands of the target signal band except the band where the target peak is located as analysis bands; The stability index of the pile foundation is determined based on the peak state of the analysis band at different heights.

2. A bridge pile foundation nondestructive testing method according to claim 1, characterized in that: Determining the peak shape characteristic factor of the peak based on the signal intensity and peak width at any peak, and the time interval between the peak and the next peak, includes: The time interval between the closest troughs on both sides of the signal waveform is taken as the peak width; The ratio of the peak signal intensity at the peak position to the peak width is used as the first characteristic index; The time interval between the next peak in the time series is used as the second characteristic index, wherein the second characteristic index of the last peak is a preset value of 1; The ratio of the first characteristic index to the second characteristic index is calculated and normalized to be the peak shape characteristic factor.

3. A non-destructive testing method for bridge pile foundation according to claim 1, characterized in that: Clustering is performed based on the peak shape characteristic factors of all peaks to obtain the target signal band inside the pile foundation, including: Clustering is performed based on the value of the peak characteristic factor. The number of clusters is set to 3, and the clusters before entering the pile foundation, the clusters inside the pile foundation, and the clusters after passing through the pile foundation are obtained. The signal band corresponding to the cluster inside the pile foundation is used as the target signal band.

4. A bridge pile foundation nondestructive testing method according to claim 1, characterized in that: The matching degree of the two peaks is determined based on the peak shape characteristic factors and the corresponding moments of the peaks in the different signal source and target signal bands, including: The time interval between the corresponding moments of two wave peaks of different signal sources is used as the first matching index; The absolute value of the difference between the peak shape characteristic factors corresponding to two peaks of different signal sources is used as the second matching index; The product value of the first matching index and the second matching index is calculated, and the inverse of the product value is normalized to obtain the result as the matching degree of the two peaks.

5. The non-destructive testing method for bridge pile foundation according to claim 1, characterized in that: The peaks that match are screened according to the matching degree to form a peak association group, including: The peaks with matching degrees greater than 0.75 in different signal sources are taken as a peak association group.

6. A bridge pile foundation nondestructive testing method according to claim 1, characterized in that: Determining a target peak of the steel-concrete contact surface according to the attenuation of the signal strength between the peak association group and the temporally adjacent association group includes: Determine the mean value of the signal intensities of all peaks in any peak association group as the peak coefficient of the corresponding peak association group; The peak correlation group that is closest to the previous one in the time sequence of any peak correlation group is regarded as the previous correlation group, and the peak correlation group that is closest to the next one in the time sequence is regarded as the next correlation group; Calculating the difference between the peak coefficients of the peak correlation group and the previous correlation group as the first correlation index; calculating the difference between the peak coefficients of the subsequent correlation group and the peak correlation group as the second correlation index; determining, according to the first correlation index and the second correlation index, whether the peak correlation group satisfies a decreasing trend; The peak association group that does not satisfy the decreasing trend is used as the target association group, and the corresponding peak in the target association group is the target peak.

7. A bridge pile foundation nondestructive testing method according to claim 6, characterized in that: Determining whether the peak association group satisfies a decreasing trend according to the first association indicator and the second association indicator includes: When both the first correlation index and the second correlation index are negative, it is determined that the peak correlation group satisfies a decreasing trend; otherwise, it is determined that the peak correlation group does not satisfy a decreasing trend.

8. A bridge pile foundation nondestructive testing method according to claim 2, characterized in that: According to the peak state of the analysis band at different heights, the stability index of the pile foundation is determined, including: Calculate the product of the signal strength corresponding to the peak and the peak width as the waveform abnormality index of the corresponding peak; The average value of the waveform anomaly index of all peaks in the analysis band corresponding to any signal source is used as the first height anomaly index; Calculate the mean of the number of peaks in the analysis bands of all signal sources, and use the ratio of the number of peaks of any signal source to the mean as the second height anomaly indicator; Normalizing the product of the first height abnormality index and the second height abnormality index to obtain a defect abnormality factor corresponding to the height of the signal source; The sum of the defect anomaly factors at the heights of all signal sources is calculated, and the opposite of the sum is normalized as the stability index of the pile foundation.

9. A non-destructive testing device for a bridge pile foundation, comprising a memory, a processor, and a computer program stored in the memory and running on the processor, characterized in that: When the processor executes the computer program, the steps of the method according to any one of claims 1 to 8 are implemented.

10. A non-destructive testing system for bridge pile foundation, characterized in that: Multiple signal sources are set at different heights of the pile foundation. The system includes: An acquisition module is used to acquire the reflected wave signal collected by each signal source and passing through the pile foundation; and to determine different peaks of the reflected wave signal; The pile foundation internal analysis module is used to determine the peak shape characteristic factor of the peak based on the signal strength and peak width at any peak, as well as the time interval between the peak and the next peak; clustering is performed based on the peak shape characteristic factors of all peaks to obtain the target signal band inside the pile foundation; The correlation analysis module is used to determine the matching degree of two peaks based on the peak shape characteristic factors and the corresponding moments of the peaks of the target signal bands of different signal sources; and to screen the matching peaks according to the matching degree to form a peak correlation group; A steel bar surface analysis module is used to determine the target peak of the steel bar-concrete contact surface based on the attenuation of the signal strength of the peak association group and the temporally adjacent association groups; and the remaining bands of the target signal band except the band where the target peak is located are used as analysis bands; The stability analysis module is used to determine the stability index of the pile foundation based on the peak state of the analysis band at different heights.

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