Bridge pile foundation nondestructive testing method, device and system

Abstract

The invention relates to the technical field of bridge pile detection, in particular to a bridge pile foundation nondestructive detection method, device and system. According to the method, a target signal wave band in a pile foundation is obtained through wave crest characteristic screening of reflected wave signals, then matched wave crest correlation groups are obtained through screening in combination with peak shape characteristic factors of different signal sources and moments corresponding to the wave crests, and then the wave crests of a reinforcing steel bar-concrete contact surface are further screened out according to analysis of the wave crest correlation groups on the time sequence. And according to the wave crest state of the analysis wave band at different heights, the stability index of the pile foundation is determined. The influence of the steel bar-concrete contact surface on stability analysis can be effectively screened, and the reliability and accuracy of stability analysis in the pile foundation are improved.

Description

Technical Field

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

[0002] Bridge pile foundations are one of the very important components in bridge engineering, and are usually used to support the upper structure of the bridge to ensure the stability of the bridge under various loads. The pile foundation transfers the load to deeper and stable soil layers or rock layers to ensure that the bridge is not affected by adverse factors such as foundation settlement, sliding or overturning. Non-destructive testing technology is an important means in the quality control of bridge pile foundations, which can obtain the structural state in real time without affecting the use, and provide strong support for bridge design, construction and maintenance.

[0003] At present, the non-destructive detection of bridge pile foundations generally utilizes the propagation characteristics of sound waves in the pile foundations, and analyzes the reflection and attenuation characteristics of the signal waveforms to detect the existence of defects in the pile foundations. However, the non-uniformity of the internal materials of the pile foundation (such as the contact surface between the steel bars and concrete in the pile foundation) will also reflect the sound wave signals, and the peak shape characteristics of these reflected wave signals may be very similar to the peak shape of the reflected waves of defects, thus affecting the recognition accuracy of defects such as holes and cracks in 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 that in the related technology, due to the similarity between the waveform of the contact surface between the steel bars and concrete in the pile foundation and the peak shape of the reflected waves of defects, the recognition of defects such as holes and cracks in the pile foundation is affected, resulting in insufficient reliability and accuracy in the analysis of the internal stability of the pile foundation, the present invention provides a non-destructive detection method, device and system for bridge pile foundations, and the specific technical solutions adopted are as follows: The present invention proposes a non-destructive detection method for bridge pile foundations, in which a plurality of signal sources are arranged at different heights of the pile foundation, and the method includes: Obtaining the reflected wave signals collected by each signal source passing through the pile foundation; determining different wave peaks of the reflected wave signals; Determining the peak shape characteristic factor of a wave peak according to the signal intensity and wave peak width at any wave peak, and the time interval between the wave peak and the next wave peak; clustering according to the peak shape characteristic factors of all wave peaks to obtain the target signal band inside the pile foundation; Determining the matching degree between two wave peaks according to the peak shape characteristic factor and the corresponding time of the wave peaks in the target signal band of different signal sources; screening according to the matching degree to obtain the matching wave peaks to form a wave peak association group; Determine the target peak of the steel - concrete contact surface according to the attenuation of the signal strength between the peak correlation group and the adjacent correlation group in time series; take the remaining bands in the target signal band except the band where the target peak is located as the analysis band; Determine the stability index of the pile foundation according to the peak state of the analysis band at different heights.

[0005] Further, determining the peak shape characteristic factor of the peak according to the signal strength, peak width at any peak, and the time interval between the peak and the next peak includes: Take the time interval between the two valleys closest in time series on both sides of the signal waveform of the peak as the peak width; Take the ratio of the peak signal strength at the peak position to the peak width as the first characteristic index; Take the time interval between the peak and the next peak in time series as the second characteristic index, where the second characteristic index of the last peak is a preset value of 1; Calculate the ratio of the first characteristic index and the second characteristic index, and perform normalization processing as the peak shape characteristic factor.

[0006] Further, clustering according to the peak shape characteristic factors of all peaks to obtain the target signal band inside the pile foundation, including: Based on the values of the peak characteristic factors, perform clustering, set the number of clustering clusters to 3, and obtain the cluster before entering the pile foundation, the cluster inside the pile foundation, and the cluster after passing through the pile foundation; Take the signal band corresponding to the cluster inside the pile foundation as the target signal band.

[0007] Further, determine the matching degree of two peaks according to the peak shape characteristic factor and the corresponding time of the peaks in the target signal band of different signal sources, including: Take the time interval between the corresponding times of two peaks of different signal sources as the first matching index; Take the absolute value of the difference between the peak shape characteristic factors corresponding to two peaks of different signal sources as the second matching index; Calculate the product value of the first matching index and the second matching index, and perform normalization processing on the opposite number of the product value as the matching degree of the two peaks.

[0008] Further, screen out the matching peaks according to the matching degree to form a peak correlation group, including: Take the peaks with a matching degree greater than 0.75 in different signal sources as a peak correlation group.

[0009] Further, determine the target peak of the steel - concrete contact surface according to the attenuation of the signal strength between the peak correlation group and the adjacent correlation group in time series, including: Determine the mean of the signal intensities of all the wave peaks in any wave peak association group as the peak coefficient corresponding to the wave peak association group; Take the wave peak association group that is the closest in sequence before any wave peak association group as the previous association group, and the wave peak association group that is the closest in sequence after it as the subsequent association group; Calculate the difference between the peak coefficient of the wave peak association group and that of the previous association group as the first association index; calculate the difference between the peak coefficient of the subsequent association group and that of the wave peak association group as the second association index; Determine whether the wave peak association group satisfies a decreasing trend according to the first association index and the second association index; Take the wave peak association group that does not satisfy the decreasing trend as the target association group, and the wave peaks corresponding to the target association group as the target wave peaks.

[0010] Further, determining whether the wave peak association group satisfies a decreasing trend according to the first association index and the second association index includes: When both the first association index and the second association index are negative, determine that the wave peak association group satisfies the decreasing trend; otherwise, determine that the wave peak association group does not satisfy the decreasing trend.

[0011] Further, determining the stability index of the pile foundation according to the wave peak states of the analysis wave bands at different heights includes: Calculate the product value of the signal intensity corresponding to the wave peak and the wave peak width as the waveform abnormality index corresponding to the wave peak; Take the mean of the waveform abnormality indexes of all the wave peaks in the analysis wave band corresponding to any signal source as the first height abnormality index; Calculate the mean of the number of wave peaks in the analysis wave bands of all the signal sources, and take the ratio of the number of wave peaks of any signal source to the mean as the second height abnormality index; Normalize the product value of the first height abnormality index and the second height abnormality index as the defect abnormality factor at the height where the corresponding signal source is located; Calculate the sum value of the defect abnormality factors at the heights where all the signal sources are located, and normalize the opposite number of the sum value as the stability index of the pile foundation.

[0012] On the other hand, 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 the method described in any one of the foregoing are implemented.

[0013] On the other hand, a non-destructive testing system for bridge pile foundations is also provided. A plurality of signal sources are arranged at different heights of the pile foundation. The system includes: An acquisition module, configured to acquire reflected wave signals passing through a pile foundation collected by each signal source; and determine different wave peaks of the reflected wave signals. An internal pile foundation analysis module, configured to determine a peak shape characteristic factor of a wave peak according to the signal intensity and wave peak width at any wave peak, and the time interval between the wave peak and the next wave peak; and perform clustering according to the peak shape characteristic factors of all wave peaks to obtain a target signal band inside the pile foundation. An association analysis module, configured to determine the matching degree between two wave peaks according to the peak shape characteristic factors and the corresponding moments of the wave peaks in the target signal bands of different signal sources; and screen to obtain matching wave peaks to form a wave peak association group according to the matching degree. A steel bar surface analysis module, configured to determine a target wave peak of the steel bar-concrete contact surface according to the attenuation condition of the signal intensity between the wave peak association group and the adjacent association group in time sequence; and use the remaining bands except the band where the target wave peak is located in the target signal band as the analysis band. A stability analysis module, configured to determine a stability index of the pile foundation according to the wave peak states of the analysis bands at different heights.

[0014] The present invention has the following beneficial effects: In the embodiment of the present invention, a target signal band inside the pile foundation is screened through the wave peak characteristics of the reflected wave signals. Then, in combination with the peak shape characteristic factors and the corresponding moments of the wave peaks of different signal sources, a matching wave peak association group is screened. After that, according to the analysis of the wave peak association group in time sequence, the wave peaks of the steel bar-concrete contact surface are further removed to obtain an analysis band, and a stability index of the pile foundation is determined according to the wave peak states of the analysis bands at different heights. The problem that the identification of defects such as holes and cracks inside the pile foundation is inaccurate due to the similarity between the waveform characteristics of the reflected wave signals generated by the non-uniformity of the internal materials of the pile foundation and the reflected waveforms of the defects is optimized, the influence of the steel bar-concrete contact surface on the stability analysis is effectively screened, and the reliability and accuracy of the internal stability analysis of the pile foundation are improved. Description of the Drawings

[0015] In order to more clearly illustrate the technical solutions and advantages in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained according to these drawings without creative efforts.

[0016] Figure 1 It is a schematic diagram of a non-destructive testing scenario of a pile foundation provided by an embodiment of the present invention. Figure 2 It is a flowchart of a non-destructive testing method for a bridge pile foundation provided by an embodiment of the present invention. Figure 3 Schematic diagram of the target signal band provided by an embodiment of the present invention; Figure 4 Schematic diagram of the peak correlation group provided by an embodiment of the present invention. Detailed implementation manners

[0017] In order to further elaborate on the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the following combines the accompanying drawings and preferred embodiments to detail a non-destructive testing method, device and system for bridge pile foundations proposed according to the present invention, its specific implementation manners, structures, features and effects. In the following description, different "one embodiment" or "another embodiment" do not necessarily refer to the same embodiment. In addition, the specific features, structures or characteristics in one or more embodiments can be combined in any suitable form.

[0018] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which the present invention belongs.

[0019] The following specifically describes the specific solution of a non-destructive testing method for bridge pile foundations provided by the present invention with reference to the accompanying drawings.

[0020] Please refer to Figure 1 and Figure 2 , Figure 1 which is a schematic diagram of a non-destructive testing scenario for pile foundations provided by an embodiment of the present invention. A plurality of signal sources are arranged at different heights of the pile foundation, and the signal sources are mainly acoustic signal probes. Figure 2 The following is a flowchart of a non-destructive testing method for bridge pile foundations provided by an embodiment of the present invention. The method includes: S101: Obtain the reflected wave signals collected by each signal source passing through the pile foundation; determine different wave peaks of the reflected wave signals.

[0021] In the embodiment of the present invention, an acoustic wave signal is emitted towards the pile foundation through an acoustic wave signal probe, and after being reflected by the pile foundation, a reflected wave signal is obtained. Through specific analysis in combination with Figure 1 , signals are emitted to different height positions of the pile foundation through a plurality of uniformly longitudinally arranged ultrasonic probes, the reflected wave signals are received, and band-pass filtering is used to remove noise. It is necessary to ensure that the signals emitted by all probes can cover the entire pile foundation area and the angles and distances between the emission ends of each probe and the pile foundation are the same. At the same time, since the pile foundation is divided into above-ground and underground parts, for the underground part, a sonic logging tube can be inserted into the ground near the pile foundation after drilling holes, and then the ultrasonic probes are connected one by one and placed into the sonic logging tube for detection. Subsequently, waveform analysis is performed based on the reflected wave signals at different positions.

[0022] In the specific waveform analysis process, since interference will occur at the contact surface between concrete and steel bars, and the waveforms in non-pile foundation areas will also cause interference, it is necessary to analyze the changes in the wave peaks of the reflected wave signals to facilitate the analysis of these interference effects. Therefore, in the embodiments of the present invention, the wave peak characteristics collected by each signal source are statistically analyzed.

[0023] S102: Determine the peak shape characteristic factor of the wave peak according to the signal intensity and wave peak width at any wave peak, and the time interval between the wave peak and the next wave peak; perform clustering according to the peak shape characteristic factors of all wave peaks to obtain the target signal band inside the pile foundation.

[0024] Since the ultrasonic probe at each signal source will emit ultrasonic signals and receive reflected wave signals, each reflected wave signal reflects the quality of the inside of the pile foundation at different transverse heights. Therefore, the stability of the pile foundation can be measured by combining the waveform characteristics of the reflected wave signals at different heights.

[0025] However, during the lateral measurement in this embodiment, the probe is not in direct contact with the pile foundation, and there are other media (soil, air) in between. Thus, the formed reflected wave contains the characteristics of these non-related regions. When detecting the stability of the pile foundation, only the reflected wave signals passing through the internal region of the pile foundation need to be considered. Therefore, this step first determines the target signal band in the internal region of the pile foundation based on the reflected wave signals.

[0026] Generally, when ultrasonic waves propagate in soil, the wave peaks are wider and the time delay is longer; after entering the pile foundation, the wave speed increases, the time of the wave peaks 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. Refer to Figure 3 , Figure 3 which is a schematic diagram of the target signal band provided by an embodiment of the present invention. Therefore, the peak shape characteristic factor of the wave peak can be determined by combining the signal intensity and wave peak width at the wave peak, and the time interval between the wave peak and the next wave peak. Thus, the target signal band in the internal region of the pile foundation can be determined according to the peak shape characteristic factor.

[0027] Further, in some embodiments of the present invention, determining the peak shape characteristic factor of the wave peak according to the signal intensity and wave peak width at any wave peak, and the time interval between the wave peak and the next wave peak includes: taking the time interval between the wave valleys with the closest time sequence on both sides of the signal waveform of the wave peak as the wave peak width; taking the ratio of the peak signal intensity at the wave peak position to the wave peak width as the first characteristic index; taking the time interval between the wave peak and the next wave peak in the time sequence as the second characteristic index, where the second characteristic index of the last wave peak is a preset value of 1; calculating the ratio of the first characteristic index and the second characteristic index, and performing normalization processing as the peak shape characteristic factor.

[0028] Among them, the wave crest width is the time interval from the position of the previous wave trough to the position of the next wave trough, which represents the "sharp" characteristic of the wave crest itself. After entering the pile foundation, the wave speed increases, the time of the wave crest shortens, and the waveform may become more "sharp", that is, the smaller the wave crest width, the more likely it is the waveform inside the pile foundation. Similarly, the greater the peak signal intensity at the wave crest position, the more likely it is the waveform inside the pile foundation.

[0029] Therefore, directly calculate the ratio of the peak signal intensity at the wave crest position to the wave crest width as the first characteristic index. The larger the value of the first characteristic index, the higher the corresponding wave crest and the more "sharp" the waveform.

[0030] Among them, since the waveforms in media such as soil and air are relatively gentle, while the waveforms in the pile foundation are relatively concentrated. The fluctuations inside the pile foundation have intense characteristics, and the distance between wave crests will become shorter. Therefore, take the time interval between the wave crest and the next wave crest in time series as the second characteristic index. The smaller the value of the second characteristic index, the more it conforms to the waveform characteristics inside the pile foundation. Therefore, directly calculate the ratio of the first characteristic index and the second characteristic index, and perform normalization processing as the peak shape characteristic factor to realize the analysis of waveform characteristics.

[0031] Since the ultrasonic signal exhibits different wave crest characteristics in different media, its 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 wave crests based on the size of the characteristic factors corresponding to different wave crests.

[0032] Furthermore, in some embodiments of the present invention, cluster according to the peak shape characteristic factors of all wave crests to obtain the target signal band inside the pile foundation, including: clustering based on the values of the wave crest characteristic factors, setting the number of clustering clusters to 3, to obtain the cluster before entering the pile foundation, the cluster inside the pile foundation, and the cluster after passing through the pile foundation; take the signal band corresponding to the cluster inside the pile foundation as the target signal band.

[0033] The clustering method in the embodiments of the present invention can be specifically, for example, k-means clustering, so as to take the signal bands corresponding to adjacent and similar characteristic wave crests as one class. Then, according to the actual scenario, divide these three clusters into the cluster before entering the pile foundation, the cluster inside the pile foundation, and the cluster after passing through the pile foundation. In the signal band, take the signal band corresponding to the middle cluster as the target signal band, or, it is also possible to calculate the mean value of the wave crest characteristic factors, and take the signal band corresponding to the cluster with the largest mean value of the wave crest characteristic factors as the target signal band.

[0034] It can be understood that during the division of the specific cluster in the signal band, the trough can be used as the division point, that is, the demarcation 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. Thus, the division of the target signal band is achieved.

[0035] S103: Determine the matching degree between two peaks according to the peak shape characteristic factor between the peaks of the target signal band of different signal sources and the moments corresponding to the peaks; Screen to obtain the matching peaks to form a peak correlation group according to the matching degree.

[0036] Through the above method, the corresponding target signal band is obtained for the signal reflection wave at any height position of the pile foundation. Since there is at least one steel bar cast in the pile foundation, the peak shape characteristics of the reflection wave signal at the steel bar-concrete contact surface may be relatively similar to the reflection peak shape of the defect. Therefore, it is necessary to screen 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 recognition.

[0037] Since the distribution of steel bars is relatively similar at different heights, thus, the feature matching of steel bars at different heights can be realized. Specifically, it is necessary to analyze the matching degree and screen to obtain the peak correlation group.

[0038] Further, in some embodiments of the present invention, determining the matching degree between two peaks according to the peak shape characteristic factor between the peaks of the target signal band of different signal sources and the moments corresponding to the peaks includes: 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 number of the product value as the matching degree between the two peaks.

[0039] Since the signal source simultaneously collects the reflection wave signals at the same frequency, thus, after encountering a vertical steel bar, the corresponding waveform change should also be at the same moment. Taking the time interval between the moments corresponding to the two peaks of different signal sources as the first matching index, the smaller the value of the first matching index, the more likely the corresponding two peaks represent the same steel bar waveform characteristic.

[0040] 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, then the smaller the value of the second matching index, it also means that the values of the peak shape characteristic factors are closer.

[0041] In summary, calculate the product value of the first matching index and the second matching index, and normalize the negative value of the product value as the matching degree of the two wave peaks. The normalization in the embodiments of the present invention is to map the result to the interval [0, 1], specifically a linear mapping, such as maximum-minimum normalization, or other linear normalization algorithms, which are not limited herein.

[0042] The larger the matching degree value of the two wave peaks, the closer the two wave peaks are, and the more similar the waveforms between the wave peaks are. Therefore, the wave peak correlation group can be determined. The wave peaks that are matched according to the matching degree form a wave peak correlation group, including: regarding the wave peaks with a matching degree greater than 0.75 in different signal sources as a wave peak correlation group.

[0043] See Figure 4 , Figure 4 which is a schematic diagram of the wave peak correlation group provided by an embodiment of the present invention. In the figure, the two wave peaks have similar characteristics, indicating that the two wave peaks have the same scene information. Each wave peak in each box in the figure belonging to different target signal bands is a wave peak correlation group. Since the above is only the result of matching based on the longitudinal similarity of the wave peaks, it cannot be considered that all these wave peaks belong to the wave peaks corresponding to the contact surface, and it is also necessary to screen them in combination with the characteristics of the contact surface wave peaks in the same signal band.

[0044] S104: Determine the target wave peak of the steel-concrete contact surface according to the attenuation of the signal intensity between the wave peak correlation group and the adjacent correlation group in time series; use the remaining bands in the target signal band except the band where the target wave peak is located as the analysis band.

[0045] For a certain signal source, its acoustic wave signal will pass through each steel-concrete contact surface after entering the pile foundation. Due to the different distances of different steel bars from the signal source transmitting end, the corresponding signal attenuation situations are different, that is, the signal reflected by the steel bar farther from the signal source transmitting end attenuates more, and the corresponding wave peak intensity is lower.

[0046] Therefore, the intensity of each contact surface wave peak from left to right in the band will show a gradually decreasing trend. Then, the attenuation characteristics of the wave peak intensities of each adjacent wave peak correlation group from left to right can be compared to screen out the target wave peak of the steel-concrete contact surface.

[0047] Further, in some embodiments of the present invention, determining the target peak of the steel bar-concrete contact surface according to the attenuation of the peak correlation group and the adjacent correlation group in time sequence includes: determining the mean value of the signal intensities of all peaks in any peak correlation group as the peak coefficient corresponding to the peak correlation group; taking the previous closest peak correlation group in time sequence of any peak correlation group as the previous correlation group, and the next closest peak correlation group in time sequence as the next correlation group; calculating the difference between the peak coefficient of the peak correlation group and that of the previous correlation group as the first correlation index; calculating the difference between the peak coefficient of the next correlation group and that of the peak correlation group as the second correlation index; determining whether the peak correlation group satisfies a decreasing trend according to the first correlation index and the second correlation index; taking the peak correlation group that does not satisfy the decreasing trend as the target correlation group, and the peak corresponding to the target correlation group as the target peak.

[0048] When analyzing the peak correlation group, it is necessary to determine the overall characteristic parameters of the peak correlation group. In the embodiments of the present invention, the mean value of the signal intensities of all peaks in any peak correlation group is calculated to obtain the peak coefficient as the characteristic parameter of the peak correlation group, so as to realize the characteristic analysis of the peak correlation group.

[0049] In order to realize the attenuation analysis, it is necessary to make the front and back settings. Take the previous closest peak correlation group in time sequence of any peak correlation group as the previous correlation group, and the next closest peak correlation group in time sequence as the next correlation group. Since the peaks show time sequence characteristics on the signal curve, the other peak correlation group closest in distance before the time sequence is used as the previous correlation group, and the other peak correlation group closest in distance after the time sequence is used as the next correlation group.

[0050] Further, in some embodiments of the present invention, determining whether the peak correlation group satisfies a decreasing trend according to the first correlation index and the second correlation index includes: when both the first correlation index and the second correlation index are negative numbers, determining that the peak correlation group satisfies a decreasing trend; otherwise, determining that the peak correlation group does not satisfy a decreasing trend.

[0051] It can be understood that in the corresponding attenuation situation in the scenario, the signal intensity of the previous correlation group is greater than that of the analyzed peak correlation group, and the analyzed peak correlation group is greater than that of the next correlation group. When the attenuation characteristics are satisfied, it can be determined that the analyzed peak correlation group is the target correlation group of the normal steel bar-concrete contact surface, and the peak in the target correlation group is the target peak. Therefore, in the embodiments of the present invention, by determining the first correlation index and the second correlation index, when both the first correlation index and the second correlation index are negative values, the attenuation characteristics are satisfied, and thus the accurate acquisition of the target peak is realized.

[0052] After determining the target peak of the steel-concrete contact surface, in order to avoid the influence of the target peak on defect analysis, the remaining bands in the target signal band except the band where the target peak is located are used as the analysis band.

[0053] S105: Determine the stability index of the pile foundation according to the peak states of the analysis bands at different heights.

[0054] Due to the longitudinal arrangement of the signal sources in this embodiment, the band corresponding to each signal source can only reflect the defect conditions at the corresponding height of the pile foundation covered by it. If we want to evaluate the defect conditions of the entire pile foundation and then conduct stability analysis, it is necessary to comprehensively evaluate by combining all the signal sources.

[0055] Further, in some embodiments of the present invention, determining the stability index of the pile foundation according to the peak states of the analysis bands at different heights includes: calculating the product value of the signal intensity and the peak width corresponding to the peak as the waveform anomaly index of the corresponding peak; taking the mean value 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 mean value of the number of peaks in the analysis bands of all signal sources, and taking the ratio of the number of peaks of any signal source to the mean value as the second height anomaly index; normalizing the product value of the first height anomaly index and the second height anomaly index as the defect anomaly factor at the height where the corresponding signal source is located; calculating the sum value of the defect anomaly factors at the heights of all signal sources, and normalizing the opposite value of the sum value as the stability index of the pile foundation.

[0056] If there are defects (holes, cracks) at a certain position of the pile foundation, these will cause multiple reflections and scattering of sound waves, resulting in a superposition state, thus obtaining more dense and high-intensity peaks. At the same time, the defects may cause a change in the propagation speed of sound waves, so the duration of the peaks will also become longer.

[0057] That is to say, due to the existence of defects, the peaks will be more dense. The larger the peak scale, the abnormal peaks have the characteristics of higher signal intensity and larger peak width. Therefore, in the embodiments of the present invention, the product value of the signal intensity and the peak width corresponding to the peak is calculated as the waveform anomaly index of the corresponding peak; the mean value of the waveform anomaly indexes of all peaks in the analysis band corresponding to any signal source is taken as the first height anomaly index, and the first height anomaly index characterizes the abnormal characteristics at the height corresponding to the signal source.

[0058] Then, calculate the mean value of the number of peaks in the analysis bands of all signal sources, and take the ratio of the number of peaks of any signal source to the mean value 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 indicates.

[0059] In summary, the product value of the first height anomaly index and the second height anomaly index is normalized as the defect anomaly factor of the height where the corresponding signal source is located. The defect anomaly factors at all heights are fused, negatively correlated and normalized as the stability index of the pile foundation.

[0060] Through the above method, more accurate detection of the stability of the pile foundation is carried out. Since the pile foundation is only the foundation of bridge construction, if the stability assessment finds problems such as instability or insufficient bearing capacity of the pile foundation, on-site drilling and sampling verification should be carried out in a timely manner, and the overall design scheme should be adjusted (increasing the number of piles, deepening the pile foundation, etc.).

[0061] At the same time, a long-term monitoring system should be established in combination with soil conditions, and the settlement, inclination, cracks, etc. of the pile foundation should be regularly checked after the bridge is built. Especially for bridges in areas with complex geological conditions or active seismic areas, the use of equipment such as sensors, settlement gauges, and accelerometers should be increased to monitor the health status of the pile foundation in real time.

[0062] In the embodiment of the present invention, the target signal band inside the pile foundation is screened through the wave peak characteristics of the reflected wave signal. Then, in combination with the peak shape characteristic factors of different signal sources and the moments corresponding to the wave peaks, a matching wave peak correlation group is screened. After that, according to the analysis of the wave peak correlation group in time sequence, the wave peaks at the steel bar-concrete contact surface are further screened out to obtain the analysis band. According to the wave peak states of the analysis band at different heights, the stability index of the pile foundation is determined. It optimizes the problem of inaccurate identification of defects such as holes and cracks inside the pile foundation caused by the similarity between the waveform characteristics of the reflected wave signal generated by the non-uniformity of the internal materials of the pile foundation and the reflected waveforms of the defects, effectively screens the influence of the steel bar-concrete contact surface on the stability analysis, and improves the reliability and accuracy of the internal stability analysis of the pile foundation.

[0063] 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 a non-destructive testing method for bridge pile foundations as described in any one of the foregoing are implemented.

[0064] In other embodiments of the present invention, a non-destructive testing system for bridge pile foundations is also provided. A plurality of signal sources are arranged at different heights of the pile foundation. The system includes: An acquisition module, configured to acquire the reflected wave signals passing through the pile foundation collected by each signal source; and determine different wave peaks of the reflected wave signals; An internal pile foundation analysis module, configured to determine the peak shape characteristic factor of a wave peak according to the signal intensity and wave peak width at any wave peak, and the time interval between the wave peak and the next wave peak; perform clustering according to the peak shape characteristic factors of all wave peaks to obtain the target signal band inside the pile foundation; The correlation analysis module is used to determine the matching degree between two wave peaks according to the peak shape characteristic factors between the wave peaks of the target signal bands of different signal sources and the moments corresponding to the wave peaks; and filter out the matching wave peaks according to the matching degree to form a wave peak correlation group. The steel bar surface analysis module is used to determine the target wave peak of the steel bar-concrete contact surface according to the attenuation of the signal intensity between the wave peak correlation group and the adjacent correlation group in time series; and use the remaining bands in the target signal band except the band where the target wave peak is located as the analysis band. The stability analysis module is used to determine the stability index of the pile foundation according to the wave peak states of the analysis bands at different heights.

[0065] Among them, the specific implementation of a non-destructive testing system for bridge pile foundations is as described in the steps of any one of the foregoing non-destructive testing methods for bridge pile foundations. The technical effects of a non-destructive testing system for bridge pile foundations and a non-destructive testing device for bridge pile foundations are the same as those of a non-destructive testing method for bridge pile foundations, and will not be further elaborated herein.

[0066] It should be noted that the above sequence of embodiments of the present invention is only for description and does not represent the advantages or disadvantages of the embodiments. The processes depicted in the drawings do not necessarily require the specific order or continuous order shown to achieve the desired results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0067] Each embodiment in this specification is described in a progressive manner, and the same or similar parts between the 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 foundations, characterized in that, Set multiple signal sources at different heights of the pile foundation. The method includes: Obtain the reflected wave signals collected by each signal source passing through the pile foundation; determine the different wave peaks of the reflected wave signals. Determine the peak shape characteristic factor of a wave peak according to the signal intensity and wave peak width at any wave peak, and the time interval between the wave peak and the next wave peak; perform clustering according to the peak shape characteristic factors of all wave peaks to obtain the target signal band inside the pile foundation. Determine the matching degree of two wave peaks according to the peak shape characteristic factor and the time corresponding to the wave peak between the wave peaks of the target signal bands of different signal sources; screen the matching wave peaks according to the matching degree to form a wave peak correlation group. Determine the target wave peak of the steel bar-concrete contact surface according to the attenuation of the signal intensity between the wave peak correlation group and the adjacent correlation group in time sequence; use the remaining bands except the band where the target wave peak is located in the target signal band as the analysis band. Determine the stability index of the pile foundation according to the wave peak state of the analysis band at different heights.

2. The non-destructive testing method for bridge pile foundation according to claim 1, characterized in that, The determining the peak shape characteristic factor of a wave peak according to the signal intensity and wave peak width at any wave peak, and the time interval between the wave peak and the next wave peak includes: Take the time interval between the two closest wave valleys in time sequence on both sides of the signal waveform of the wave peak as the wave peak width. Take the ratio of the peak signal intensity at the wave peak position to the wave peak width as the first characteristic index. Take the time interval between the wave peak and the next wave peak in time sequence as the second characteristic index, where the second characteristic index of the last wave peak is a preset value of 1. Calculate the ratio of the first characteristic index and the second characteristic index, and perform normalization processing as the peak shape characteristic factor.

3. The non-destructive testing method for bridge pile foundation according to claim 1, characterized in that, Performing clustering according to the peak shape characteristic factors of all wave peaks to obtain the target signal band inside the pile foundation includes: Perform clustering based on the numerical values of the wave peak characteristic factors, set the number of clustering clusters to 3, and obtain the cluster before entering the pile foundation, the cluster inside the pile foundation, and the cluster after passing through the pile foundation. Take the signal band corresponding to the cluster inside the pile foundation as the target signal band.

4. The non-destructive testing method for bridge pile foundations according to claim 1, characterized in that, Determining the matching degree of two wave peaks according to the peak shape characteristic factor and the time corresponding to the wave peak between the wave peaks of the target signal bands of different signal sources includes: Take the time interval between the times corresponding to the two wave peaks of different signal sources as the first matching index. Take the absolute value of the difference between the peak shape characteristic factors corresponding to the two wave peaks of different signal sources as the second matching index. Calculate the product value of the first matching index and the second matching index, and perform normalization processing on the opposite number of the product value as the matching degree of the two wave peaks.

5. The non-destructive testing method for bridge pile foundations according to claim 1, characterized in that, Screening the matching wave peaks according to the matching degree to form a wave peak correlation group includes: Take the wave peaks with a matching degree greater than 0.75 among different signal sources as a wave peak correlation group.

6. The non-destructive testing method for bridge pile foundation according to claim 1, characterized in that Determining the target wave peak of the steel bar-concrete contact surface according to the attenuation of the signal intensity between the wave peak correlation group and the adjacent correlation group in time sequence includes: Determine the mean value of the signal intensities of all wave peaks in any wave peak correlation group as the peak coefficient corresponding to the wave peak correlation group. Take the closest wave peak correlation group before the current wave peak correlation group in time sequence as the previous correlation group, and the closest wave peak correlation group after the current wave peak correlation group in time sequence as the subsequent correlation group. Calculate the difference between the peak coefficient of the peak correlation group and the previous correlation group as the first correlation index; calculate the difference between the peak coefficient of the post-correlation group and the peak correlation group as the second correlation index. Determine whether the peak correlation group satisfies a decreasing trend according to the first correlation index and the second correlation index. Take the peak correlation group that does not satisfy the decreasing trend as the target correlation group, and the peak corresponding to the target correlation group is the target peak.

7. The non-destructive testing method for bridge pile foundations according to claim 6, characterized in that, Determine whether the peak correlation group satisfies a decreasing trend according to the first correlation index and the second correlation index, including: When both the first correlation index and the second correlation index are negative, determine that the peak correlation group satisfies the decreasing trend; otherwise, determine that the peak correlation group does not satisfy the decreasing trend.

8. A non-destructive testing method for bridge pile foundations according to claim 2, characterized in that, Determine the stability index of the pile foundation according to the peak state of the analysis band at different heights, including: Calculate the product value of the signal intensity and the peak width corresponding to the peak as the waveform anomaly index of the corresponding peak. Take the mean value of the waveform anomaly indexes of all peaks in the analysis band corresponding to any signal source as the first height anomaly index. Calculate the mean value of the number of peaks in the analysis bands of all signal sources, and take the ratio of the number of peaks of any signal source to the mean value as the second height anomaly index. Normalize the product value of the first height anomaly index and the second height anomaly index as the defect anomaly factor at the height where the corresponding signal source is located. Calculate the sum value of the defect anomaly factors at the heights where all signal sources are located, and normalize the opposite value of the sum value as the stability index of the pile foundation.

9. A non-destructive testing device for bridge pile foundations, the device 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, it implements the steps of the method according to any one of claims 1 to 8.

10. A non-destructive testing system for bridge pile foundations, characterized in that, A plurality of signal sources are arranged at different heights of the pile foundation, and the system includes: An acquisition module for acquiring the reflected wave signals passing through the pile foundation collected by each signal source; determining different peaks of the reflected wave signals. An internal pile foundation analysis module for determining the peak shape characteristic factor of the peak according to the signal intensity and peak width at any peak, and the time interval between the peak and the next peak; clustering according to the peak shape characteristic factors of all peaks to obtain the target signal band inside the pile foundation. A correlation analysis module for determining the matching degree of two peaks according to the peak shape characteristic factor and the time corresponding to the peak between the peaks of the target signal bands of different signal sources; screening the matching peaks according to the matching degree to form a peak correlation group. A steel bar surface analysis module for determining the target peak of the steel bar-concrete contact surface according to the attenuation of the signal intensity between the peak correlation group and the adjacent correlation group in time series; taking the remaining bands in the target signal band except the band where the target peak is located as the analysis band. A stability analysis module for determining the stability index of the pile foundation according to the peak state of the analysis band at different heights.

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