Electromagnetic wave detection method and device for bridge prestressed duct grouting defect

Abstract

The invention relates to the technical field of engineering quality detection, and discloses a bridge prestressed duct grouting defect electromagnetic wave detection method and device. Wherein the hole channel is arranged in a bridge concrete structure, a grouting material and a steel strand are arranged in the hole channel, and an electromagnetic excitation device is arranged on the surface of the concrete structure and is used for transmitting an electromagnetic pulse with a specified frequency to a detection position of the hole channel. The method comprises the following steps: determining vibration time sequence data of a steel strand in a pore channel based on vibration signals detected by vibration sensors distributed on the surface of a concrete structure, and analyzing the vibration time sequence data to obtain detection peak data of the vibration time sequence data and detection frequency data of vibration of the steel strand under specified frequency electromagnetic pulse; and finally, performing grouting defect detection on the detection position according to the detection peak data and / or the detection frequency data to obtain a grouting defect detection result of the detection position. Therefore, the method for effectively detecting the grouting defect of the duct in the prestressed concrete structure of the bridge is realized.

Description

Technical Field

[0001] The present application relates to the technical field of engineering quality detection, and in particular to a method and device for detecting electromagnetic wave defects in grouting of prestressed ducts of bridges. Background Art

[0002] Prestressed structures are commonly used in large-span concrete bridges to resist the deadweight of the bridge and the upper live load. Prestressed steel strands are the main tensile force bearers in prestressed concrete structures. The construction of prestressed steel strands includes processes such as pre-buried channel cable threading, post-tensioning, anchoring and channel grouting. Among them, channel grouting has a protective and filling effect on prestressed pipelines. Incomplete grouting or even voids will bring serious quality risks to the long-term use of prestressed steel strands. Ultrasonic waves, impact echo methods, etc. are often used in related technologies to identify the fullness of channel grouting. CN106680380A provides a system and detection method for ultrasonic guided wave non-destructive detection of defects in prestressed steel strands. The system independently designs digital signal processing boards and adopts a combined transceiver detection method. However, it may require professional technicians to operate, and there are detection limitations for steel strands buried in concrete; CN110779959A provides a prestressed channel grouting density detection device and detection method, which detects the resistance value through a resistance detector and judges the density of the grouting at the monitoring point according to the measured resistance value, but it will be affected by environmental factors such as humidity and temperature, and the detection effect is limited for deep or complex structure channels. Therefore, it is necessary to propose a new grouting defect detection method for bridge prestressed channel grouting construction. Summary of the invention

[0003] The present application aims to solve at least one of the technical problems in the related art to a certain extent. To this end, the present application proposes an electromagnetic wave detection method and device for grouting defects in prestressed ducts of bridges. The main technical solutions adopted in the present application include: In the first aspect, an embodiment of the present application provides an electromagnetic wave detection method for grouting defects in prestressed channels of bridges, wherein the channels are arranged in a concrete structure, and grouting material and steel strands are provided in the channels, and an electromagnetic excitation device and a vibration sensor are deployed on the surface of the concrete structure. The electromagnetic excitation device is used to transmit an electromagnetic pulse of a specified frequency to the detection position of the channel, and the vibration sensor is used to detect the vibration signal caused by the electromagnetic pulse of the specified frequency to the steel strands at the detection position. The method comprises: determining the vibration time series data of the steel strands based on the vibration signal detected by the vibration sensor. The vibration time series data is analyzed to obtain the detection peak data of the vibration time series data and the detection frequency data of the steel strands vibrating under the electromagnetic pulse of the specified frequency. The detection position is subjected to grouting defect detection according to the detection peak data and / or the detection frequency data to obtain the grouting defect detection result of the detection position.

[0004] In the second aspect, the embodiment of the present application also provides a calibration method for an electromagnetic wave detection device for grouting defects in a prestressed channel of a bridge, the device comprising an electromagnetic excitation device and a vibration sensor, the electromagnetic excitation device and the vibration sensor being deployed on the surface of a concrete model, the concrete model having a channel model, the channel model having grouting material and steel strands, the electromagnetic excitation device being used to transmit a test electromagnetic pulse to a test position of the channel model, and the vibration sensor being used to detect a vibration signal caused by the test electromagnetic pulse to the steel strand at the test position. The calibration method comprises: determining the test vibration time series data of the steel strand based on the vibration signal detected by the vibration sensor. The test vibration time series data is analyzed to obtain the test peak data of the test vibration time series data and the test frequency data of the steel strand vibrating under the test electromagnetic pulse. The frequency-length relationship data corresponding to the test electromagnetic pulse is constructed according to the test peak data and the test frequency data. Among them, the frequency-length relationship data is used to describe the corresponding relationship between the test frequency and the grouting defect length at the test position.

[0005] In a third aspect, an embodiment of the present application provides an electromagnetic wave detection device for grouting defects in prestressed channels of bridges. The channels are arranged in a concrete structure, and grouting material and steel strands are arranged in the channels. An electromagnetic excitation device and a vibration sensor are deployed on the surface of the concrete structure. The electromagnetic excitation device is used to transmit an electromagnetic pulse of a specified frequency to the detection position of the channel, and the vibration sensor is used to detect the vibration signal caused by the electromagnetic pulse of the specified frequency to the steel strands at the detection position. The device includes: a vibration data determination module, which is used to determine the vibration time series data of the steel strands based on the vibration signal detected by the vibration sensor. A peak frequency analysis module is used to analyze the vibration time series data to obtain the detection peak data of the vibration time series data and the detection frequency data of the steel strands vibrating under the electromagnetic pulse of the specified frequency. A grouting defect detection module is used to perform grouting defect detection on the detection position according to the detection peak data and / or the detection frequency data to obtain the grouting defect detection result of the detection position.

[0006] In a fourth aspect, the embodiment of the present application also provides an electromagnetic wave detection and calibration device for grouting defects of prestressed channels of bridges, the device comprising an electromagnetic excitation device and a vibration sensor, the electromagnetic excitation device and the vibration sensor being deployed on the surface of a concrete model, the concrete model having a channel model, the channel model having grouting material and steel strands, the electromagnetic excitation device being used to transmit a test electromagnetic pulse to a test position of the channel model, and the vibration sensor being used to detect a vibration signal caused by the test electromagnetic pulse to the steel strand at the test position. The device comprises: a test vibration data determination module, a test frequency determination module and a frequency-length relationship determination module, wherein: the test vibration data determination module is used to determine the test vibration time series data of the steel strand based on the vibration signal detected by the vibration sensor. The test frequency determination module is used to analyze the test vibration time series data to obtain the test peak value data of the test vibration time series data and the test frequency data of the steel strand vibrating under the test electromagnetic pulse. The frequency-length relationship determination module is used to construct the frequency-length relationship data corresponding to the test electromagnetic pulse according to the test peak value data and the test frequency data. Among them, the frequency-length relationship data is used to describe the corresponding relationship between the test frequency and the grouting defect length at the test position.

[0007] In the fifth aspect, the embodiment of the present application also provides an electromagnetic wave detection device for grouting defects in prestressed ducts of bridges, which includes a controller, a data acquisition device, an electromagnetic excitation device and a vibration sensor. The electromagnetic excitation device and the vibration sensor are respectively used to be deployed on the surface of a concrete structure. The duct in the concrete structure has grouting material and steel strands. The controller is connected to the electromagnetic excitation device and the vibration sensor respectively. The vibration sensor is connected to the data acquisition device. The electromagnetic excitation device is used to emit a test electromagnetic pulse to the detection position of the duct. The vibration sensor is used to detect the vibration signal caused by the test electromagnetic pulse to the steel strand at the detection position. The data acquisition device is used to determine the vibration time series data of the steel strand based on the vibration signal detected by the vibration sensor. The controller is used to perform grouting defect detection on the detection position according to the vibration time series data to obtain the grouting defect detection result of the detection position.

[0008] In a sixth aspect, the present application further provides a computer device including a memory and a processor, wherein the memory stores a computer program, and the processor implements the steps of any of the above methods when executing the computer program.

[0009] In a seventh aspect, the present application also provides a computer-readable storage medium having a computer program stored thereon, which implements the steps of any of the above methods when the computer program is executed by a processor.

[0010] In an eighth aspect, the present invention further provides a computer program product, comprising a computer program, which implements the steps of any of the above methods when executed by a processor.

[0011] In the above embodiment, the vibration time series data of the steel strand in the hole is determined based on the vibration signal detected by the vibration sensor distributed on the surface of the concrete structure, and the vibration time series data is further analyzed to obtain the detection peak data of the vibration time series data and the detection frequency data of the steel strand vibrating under the electromagnetic pulse of the specified frequency, and finally the grouting defect detection is performed on the detection position according to the detection peak data and / or the detection frequency data to obtain the grouting defect detection result of the detection position. At this point, a method capable of effectively detecting grouting defects in the hole in the prestressed concrete structure of the bridge is realized. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] In order to more clearly illustrate the specific implementation methods of the present application or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0013] Figure 1 A flow chart of an electromagnetic wave detection method for grouting defects in prestressed ducts of bridges provided according to one embodiment of the present application; Figure 2 A flow chart of an electromagnetic wave detection method for grouting defects in prestressed ducts of bridges provided according to another embodiment of the present application; Figure 3 A flow chart of an electromagnetic wave detection method for grouting defects in prestressed ducts of bridges provided according to another embodiment of the present application; Figure 4 A flow chart for determining the length of a grouting defect according to an embodiment of the present application; Figure 5 A flow chart of a calibration method of an electromagnetic wave detection device for grouting defects in prestressed ducts of bridges provided according to an embodiment of the present application; Figure 6a A schematic diagram of a scene of an electromagnetic wave detection method for grouting defects in prestressed ducts of bridges provided according to an embodiment of the present application; Figure 6b A flow chart of an electromagnetic wave detection method for grouting defects in prestressed ducts of bridges provided according to one embodiment of the present application; Figure 7 This is a structural block diagram of an electromagnetic wave detection device for grouting defects in prestressed ducts of bridges provided according to an embodiment of the present application; Figure 8 This is a structural block diagram of an electromagnetic wave detection and calibration device for grouting defects in prestressed ducts of bridges provided according to an embodiment of the present application; Fig. 9A structural block diagram of an electromagnetic wave detection device for grouting defects in prestressed ducts of bridges provided according to another embodiment of the present application; Fig.10 The internal structure diagram of a computer device provided according to one embodiment of the present application. DETAILED DESCRIPTION

[0014] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present application.

[0015] Prestressed steel strands are the main tensile force bearers in prestressed concrete structures. The construction of prestressed steel strands includes pre-buried cable passage, post-tensioning, anchoring and grouting. The specific construction process includes: 1. Before pouring concrete, bury holes at the predetermined positions and then pass the steel strands through these holes; 2. After the concrete is poured and begins to harden, stretch the steel strands, just like tightening a bowstring, to apply prestress to the concrete; 3. Use anchors to fix the stretched steel strands to prevent them from rebounding; 4. Grout the holes to fix the steel strands in the correct position and protect them from corrosion. Among them, hole grouting has a protective and filling effect on prestressed pipelines. Incomplete grouting or even hollow grouting will bring serious quality risks to the long-term use of prestressed steel strands.

[0016] There is a lack of more effective detection methods in the related art. CN115389546A provides a device and method for monitoring the density of grouting of prestressed bridge channels, using optical fiber monitoring equipment to replace traditional methods such as impact echo method, ultrasonic detection method and ground penetrating radar method to achieve automatic monitoring, but it may require professional equipment and technology for monitoring, and has certain technical requirements for on-site technicians. CN106680380A provides a system and detection method for ultrasonic guided wave non-destructive detection of defects in prestressed steel strands, which has independently designed digital signal processing boards, low cost and easy maintenance. The transmission attenuation of ultrasonic guided waves is small, the detection distance is farther, and the detection efficiency is improved. However, it may require professional technicians to operate, and there may be detection limitations for steel strands buried in concrete. CN110779959A provides a device and method for detecting the density of grouting of prestressed channels, which detects the resistance value through a resistance detector, and judges the density of grouting at the monitoring point according to the measured resistance value. The operation is simple and the cost is low. However, it may be affected by environmental factors such as humidity and temperature, and the detection effect of deep or complex holes is limited. It is difficult to identify using ultrasonic and impact echo methods, and the wall of the pre-buried hole causes great interference to the detection. Specifically, because the inner wall of the hole in the prestressed concrete structure is not always flat and smooth, there may be rough areas or curved areas. In this case, when using ultrasonic or impact echo methods and other technologies for detection, the curved or uneven pipe wall will cause multiple reflections of the ultrasonic wave, which may cause signal distortion and difficult to accurately judge. And the complex geometry of the pipeline may complicate the ultrasonic path and affect the accuracy of the detection results. In addition, the materials of the holes in the prestressed concrete structure include metal materials and non-metal materials. If ultrasonic or impact echo methods and other technologies are used to detect metal materials, the metal pipe wall may scatter the ultrasonic energy in multiple directions, reducing the focus and detection accuracy of the signal; if grouting defect detection is performed on the hole of non-metallic material, the penetration of the ultrasonic or impact echo method and other technologies will be greatly reduced, thereby affecting the accuracy and reliability of grouting defect detection. In contrast, if electromagnetic pulses are used for grouting defect detection, no matter what material it is, because steel strands have a good response to electromagnetic pulses, electromagnetic pulses can generate forces on steel strands to cause them to vibrate. Therefore, the use of electromagnetic pulses will not be affected by whether the pipeline material is metal or not, and has better applicability in non-metallic environments. In addition, because electromagnetic pulse technology relies more on the interaction between the electromagnetic field and steel strands, rather than the mechanical propagation of sound waves, electromagnetic pulse technology has better anti-interference ability for interference with the geometric shape and internal structure of the pipeline.

[0017] Based on this, according to an embodiment of the present application, an electromagnetic wave detection method and device embodiment of grouting defects in prestressed ducts of bridges is provided. It should be noted that the steps shown in the flowchart of the accompanying drawings can be executed in a computer system such as a set of computer executable instructions, and although the logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in an order different from that shown here.

[0018] In this embodiment, an electromagnetic wave detection method for grouting defects in a prestressed channel of a bridge is provided. The channel is arranged in a concrete structure, and grouting material and steel strands are arranged in the channel. An electromagnetic excitation device and a vibration sensor are deployed on the surface of the concrete structure. The electromagnetic excitation device is used to transmit an electromagnetic pulse of a specified frequency to a detection position of the channel, and the vibration sensor is used to detect a vibration signal caused by the electromagnetic pulse of the specified frequency to the steel strand at the detection position. Figure 1 : is a flow chart of a method for electromagnetic wave detection of grouting defects in prestressed ducts of bridges according to an embodiment of the present application, such as Figure 1 As shown, the process includes the following steps: S110. Determine vibration time series data of the steel strand based on the vibration signal detected by the vibration sensor.

[0019] Among them, the vibration time series data can be a vibration signal recorded in a time series, which can be used to represent the vibration signal data caused by the resonance generated by the steel strand in the channel under the concrete structure when it senses the electromagnetic pulse of the specified frequency emitted by the electromagnetic excitation device. Exemplarily, the electromagnetic pulse frequency that is most likely to cause the steel strand to resonate can be taken as the specified frequency of the electromagnetic pulse sent by the electromagnetic excitation device. Specifically, the electromagnetic excitation device transmits an electromagnetic pulse of a specified frequency to the detection position of the channel, and the vibration sensor detects the vibration of the steel strand at the detection position due to the electromagnetic pulse and converts it into an electrical signal. Finally, the vibration sensor data time curve at the specified frequency is recorded by the data acquisition device, that is, the vibration time series data of the steel strand under the electromagnetic pulse of the specified frequency is obtained.

[0020] S120, analyzing the vibration time series data to obtain detection peak data of the vibration time series data and detection frequency data of the steel strand vibrating under an electromagnetic pulse of a specified frequency.

[0021] The detection peak data may refer to the maximum amplitude data recorded in a time series of a vibration signal generated by resonance induced by an electromagnetic pulse of a specified frequency when the steel strand at the detection position is subjected to. Exemplarily, the maximum amplitude value of the vibration signal may be used as the detection peak data, or a vibration peak curve drawn when the maximum amplitude value changes with time may be used as the detection peak data of the vibration signal. It is understandable that the detection frequency data may refer to the frequency data obtained by analyzing the vibration signal generated by resonance induced by an electromagnetic pulse of a specified frequency when the steel strand at the detection position is subjected to.

[0022] Specifically, the vibration time series data captured by the vibration sensor at the corresponding frequency when the electromagnetic excitation device applies an electromagnetic pulse of a specified frequency to the detection position to cause the steel strand to vibrate can be recorded by the data acquisition device. The detection peak data at the detection position can be extracted by analyzing the time curve of these vibration time series data. Further, the detection peak data is analyzed and processed to obtain the detection frequency data of the steel strand vibrating at the detection position under the electromagnetic pulse of the specified frequency. Exemplarily, the peak points of the vibration time series data detected at the detection position can be plotted into a detection peak curve in time sequence, wherein the abscissa can represent time and the ordinate represents the peak value, and the detection peak data of the vibration time series data at the detection position can be obtained. Further, the vibration time series data is applied with a fast Fourier transform (FFT) or a short-time Fourier transform (STFT) to analyze the frequency component of the vibration signal, and the process of the amplitude of the frequency component changing with the frequency is plotted into a detection frequency curve, that is, as the detection frequency data of the steel strand vibrating at the detection position under the electromagnetic pulse of the specified frequency. Among them, the abscissa can represent the frequency and the ordinate represents the amplitude.

[0023] S130, performing grouting defect detection on the detection position according to the detection peak data and / or the detection frequency data, and obtaining a grouting defect detection result of the detection position.

[0024] Among them, grouting defect detection is a non-destructive testing technology that can be used to identify and evaluate the fullness of grouting and the length of grouting defects in the channels inside the concrete structure. A value greater than can be used as the grouting defect length to represent the distance of the hollow area where the grouting is not full in the channel. It should be noted that if the grouting in the channel is full, the grouting defect length can be regarded as equal to 0. Exemplarily, the vibration signal caused by the electromagnetic pulse of a specified frequency on the steel strand at the detection position can be analyzed to detect whether there are gaps or grouting defects in the bonding between the grouting material and the steel strand in the channel. Among them, the vibration signal captured by the vibration sensor at the detection position reflects the dynamic vibration response inside the channel, and these dynamic vibration responses are closely related to the fullness of the grouting inside the channel. For example, when the grouting material in the duct is well bonded to the steel strand without gaps, the duct with full grouting has higher structural stiffness and damping, which can more effectively absorb and dissipate vibration energy or suppress the amplitude of vibration, resulting in a smaller signal amplitude captured by the vibration sensor; similarly, when the grouting material in the duct is poorly bonded to the steel strand and there are voids, the grouting defect area will reduce the structural stiffness and damping, making the vibration easier to propagate, so that the amplitude of the signal captured by the vibration sensor is larger. Therefore, by analyzing whether the detection peak data and / or detection frequency data obtained at the detection position under the specified frequency electromagnetic pulse is abnormal, it is determined whether there is a grouting defect phenomenon at the detection position under the specified frequency electromagnetic pulse, and finally the grouting defect detection result of the duct at the detection position is obtained. If the grouting defect detection result shows that there is a grouting defect phenomenon at the detection position under the specified frequency electromagnetic pulse, the specific grouting defect length of the duct at the detection position can also be further determined by analyzing the detection peak data and / or detection frequency data obtained at the detection position.

[0025] Specifically, the pore model under the grouting defect state can be calibrated in advance through a calibrated vibration test, and the detection position can be calibrated with a specified frequency electromagnetic pulse to obtain the test peak data and test frequency data of the pore model measured at the test position under the specified frequency electromagnetic pulse. Further, based on the analysis of the detection peak data and / or detection frequency data, the test peak data and test frequency data obtained through the calibrated vibration test are identified and compared with the detection peak data and detection frequency data obtained in the actual grouting defect detection. Exemplarily, the test peak data and test frequency data obtained through the calibrated vibration test are used as a reference to identify abnormal detection peak data and / or detection frequency data, so as to determine whether there is a grouting defect in the pore at the detection position under the specified frequency electromagnetic pulse. If the grouting defect detection shows that there is a grouting defect at the detection position under the condition of an electromagnetic pulse of a specified frequency, then the correspondence between the test frequency data and the grouting defect length, i.e., the frequency-length relationship data, is further constructed based on the test peak data and test frequency data measured at the test position of the pore model under the grouting defect state to determine the specific grouting defect length of the pore at the detection position under the condition of an electromagnetic pulse of a specified frequency.

[0026] In the above implementation, the vibration time series data of the steel strand in the hole is determined based on the vibration signal detected by the vibration sensor distributed on the surface of the concrete structure, and the vibration time series data is further analyzed to obtain the detection peak data of the vibration time series data and the detection frequency data of the steel strand vibrating under the electromagnetic pulse of the specified frequency, and finally the grouting defect detection is performed on the detection position according to the detection peak data and / or the detection frequency data to obtain the grouting defect detection result of the detection position. At this point, a method capable of effectively detecting grouting defects in the hole in the prestressed concrete structure is realized.

[0027] In some embodiments, grouting defect detection is performed on the detection position based on detection peak data and / or detection frequency data to obtain a grouting defect detection result of the detection position, including: when the detection peak data is less than the first calibration peak data, determining that the detection position is in a full grouting state.

[0028] Among them, the first calibration peak data can be determined by calibrating the vibration detection of the pore model in the grouting full state using an electromagnetic pulse of a specified frequency in advance. Exemplarily, the electromagnetic pulse of the specified frequency is used as a test electromagnetic pulse, and the resonance is excited by applying the test electromagnetic pulse to the steel strand in the pore model in the grouting full state, and the test vibration time series data generated thereby is recorded, which includes the response characteristics of the pore model in the grouting full state. The test vibration time series data is analyzed to obtain the test peak data of the test vibration time series data, and the test peak data can be used as the first calibration peak data. Furthermore, if the detection peak data is less than the first calibration peak data, it is considered that under the condition of the electromagnetic pulse of the specified frequency, the dynamic vibration response inside the pore at the detection position is less than the dynamic vibration response inside the pore of the pore model in the grouting full state. Based on the bonding characteristics between the grouting material and the steel strand in the hole, when the grouting material and the steel strand in the hole are well bonded without gaps, the hole with full grouting has higher structural stiffness and damping, which will more effectively absorb and dissipate vibration energy or suppress the amplitude of vibration, resulting in a smaller signal amplitude captured by the vibration sensor. Therefore, if the detection peak data is less than the first calibration peak data, it can be considered that under the condition of the specified frequency electromagnetic pulse, the hole is in a full grouting state at the detection position.

[0029] In the above embodiment, when the detection peak data and the detection frequency data have been obtained, by comparing the first calibrated peak data obtained by pre-vibration detection of the pore model in a full grouting state using an electromagnetic pulse of a specified frequency with the detection peak data, it is possible to perform grouting defect detection on the detection position of the pore and obtain the grouting defect detection result of the detection position under the condition of an electromagnetic pulse of a specified frequency, thereby improving the efficiency of grouting defect detection on the pores in prestressed concrete structures.

[0030] In some embodiments, please refer to the attached Figure 2 , perform grouting defect detection on the detection position according to the detection peak data and / or detection frequency data, and obtain the grouting defect detection result of the detection position, including: S210: Determine a target frequency interval in a frequency range corresponding to the detected frequency data.

[0031] The detection frequency data may refer to the frequency data obtained by analyzing the vibration signal generated by the resonance of the steel strand at the detection position caused by the electromagnetic pulse of the specified frequency. The target frequency interval is used to determine the target vibration frequency based on which the grouting defect detection is performed at the detection position of the hole under the condition of the electromagnetic pulse of the specified frequency, and the frequency range in the detection frequency data. For example, a certain interval range where the vibration energy shows abnormality or the detection frequency data has abnormal peak value can be taken as the target frequency interval.

[0032] S220, performing mean calculation according to the target frequency interval to obtain the target vibration frequency of the steel strand under the electromagnetic pulse of the specified frequency.

[0033] For example, the detection frequency data may have multiple abnormal peaks, and it is necessary to calculate the mean of all target frequency intervals where abnormal peaks appear, and finally obtain the most representative vibration frequency as the target vibration frequency of the steel strand at the detection position under the specified frequency electromagnetic pulse.

[0034] S230, searching in the frequency-length relationship data according to the target vibration frequency to obtain the grouting defect length at the detection position.

[0035] Among them, a value greater than 0 can be used as the grouting defect length to represent the distance of the hollow area in the pore where the grouting is not full. It should be noted that if the grouting in the pore is full, the grouting defect length can be regarded as equal to 0. The frequency-length relationship data is the correspondence between the test frequency data measured at the test position and the grouting defect length, which is obtained by pre-calibrating the vibration detection of the pore model under the grouting defect state using a specified frequency electromagnetic pulse. Exemplarily, the frequency-length relationship data can be a table or database formed by mapping the test frequency data to the grouting defect length, or it can be a polynomial function with the test frequency data as the independent variable and the grouting defect length as the dependent variable. Specifically, the specified frequency electromagnetic pulse is used as the test electromagnetic pulse, and the calibrated vibration detection is performed on the pore model under different grouting defect states. The correspondence between the test frequency data and the grouting defect length measured at the test position of the pore model with different grouting defect states under the test electromagnetic pulse is obtained, and it can be used as the frequency-length relationship data. After determining the frequency-length relationship data under the electromagnetic pulse of the specified frequency, the target vibration frequency is substituted into the determined frequency-length relationship data to search for the grouting defect length of the duct at the detection position.

[0036] In the above implementation, by pre-establishing the corresponding relationship between the test frequency data and the grouting defect length measured at the test position using a specified frequency electromagnetic pulse for the duct model in the grouting defect state, the process of performing grouting defect detection on the detection position and obtaining the grouting defect detection result of the duct at the detection position is realized under the specified frequency electromagnetic pulse condition. Through this search method, a quantitative evaluation of the grouting defect length of the duct inside the concrete structure can be achieved, and the grouting defect detection result of the detection position of the duct in the prestressed concrete structure can be obtained more intuitively.

[0037] In some embodiments, please refer to the attached Figure 3, perform grouting defect detection on the detection position according to the detection peak data and / or detection frequency data, and obtain the grouting defect detection result of the detection position, including: S310: When there is excess peak data greater than the second calibration peak data in the detected peak data, determine a frequency interval corresponding to the excess peak data.

[0038] Among them, the second calibration peak data can be determined by calibrating the vibration detection of the pore model under the grouting defect state using an electromagnetic pulse of a specified frequency in advance. Specifically, the electromagnetic pulse of the specified frequency is used as a test electromagnetic pulse, and calibration vibration detection is performed on the pore model under different grouting defect states to obtain the second calibration peak data of the pore model under different grouting defect states under different test electromagnetic pulses. It can be understood that if there is an excess peak data greater than the second calibration peak data in the detection peak data, then the frequency interval corresponding to all the detection peak data greater than the second calibration peak data is obtained as the excess peak data.

[0039] S320, determining the grouting defect length at the detection position according to the frequency interval corresponding to the peak value data and the frequency-length relationship data.

[0040] Among them, a value greater than 0 can be used as the grouting defect length to represent the distance of the hollow area in the pore where the grouting is not full. It should be noted that if the grouting in the pore is full, the grouting defect length can be regarded as equal to 0. The frequency-length relationship data is the correspondence between the test frequency data and the grouting defect length measured at the test position by pre-calibrating the vibration detection of the pore model under the grouting defect state using a specified frequency electromagnetic pulse. Exemplarily, the frequency-length relationship data can be a table or database formed by mapping the test frequency data to the grouting defect length, or it can be a polynomial function with the test frequency data as the independent variable and the grouting defect length as the dependent variable. Specifically, the specified frequency electromagnetic pulse is used as the test electromagnetic pulse, and the calibrated vibration detection is performed on the pore model under different grouting defect states. The correspondence between the test frequency data and the grouting defect length measured at the test position of the pore model under different grouting defect states under the test electromagnetic pulse is obtained, and it can be used as the frequency-length relationship data. Furthermore, the frequency interval corresponding to the data exceeding the peak value is determined, and the median value of the frequency interval is taken as the target vibration frequency corresponding to the data exceeding the peak value. After determining the frequency-length relationship data under the electromagnetic pulse of the specified frequency, the target vibration frequency corresponding to the data exceeding the peak value is substituted into the corresponding frequency-length relationship data to calculate the grouting defect length of the duct at the detection position.

[0041] In the above implementation, the detected peak data is compared with the second calibration peak data to determine the exceeded peak data, and the target vibration frequency corresponding to the exceeded peak data is determined based on the frequency interval corresponding to the exceeded peak data and substituted into the corresponding frequency-length relationship data to calculate the grouting defect length of the duct at the detection position. Through this calculation method, a quantitative evaluation of the grouting defect length of the duct inside the concrete structure can be achieved, and the grouting defect detection result of the detection position of the duct in the prestressed concrete structure can be obtained more quickly.

[0042] In some embodiments, please refer to the attached Figure 4 , according to the frequency interval and frequency-length relationship data corresponding to the peak value data, the length of the grouting defect at the detection position is determined, including: S410, performing mean calculation according to the frequency interval corresponding to the peak value data, and obtaining the target vibration frequency of the steel strand under the electromagnetic pulse of the specified frequency.

[0043] For example, if there are multiple data exceeding the peak value, it is necessary to perform mean calculation on the frequency intervals where all the data exceeding the peak value are located, and finally obtain the most representative frequency interval as the data exceeding the peak value of the steel strand vibrating under the electromagnetic pulse of the specified frequency at the detection position. Further, the frequency interval corresponding to the data exceeding the peak value is determined according to the data exceeding the peak value, and the mean calculation is performed again in the frequency interval to obtain the target vibration frequency corresponding to the data exceeding the peak value, that is, the target vibration frequency of the steel strand vibrating under the electromagnetic pulse of the specified frequency at the detection position.

[0044] S420, searching in the frequency-length relationship data according to the target vibration frequency to obtain the grouting defect length at the detection position.

[0045] Among them, a value greater than 0 can be used as the grouting defect length to indicate the distance of the hollow area in the channel where the grouting is not full. It should be noted that if the grouting in the channel is full, the grouting defect length can be regarded as equal to 0. The frequency-length relationship data is the correspondence between the test frequency data measured at the test position and the grouting defect length, which is obtained by calibrating the vibration detection of the channel model under the grouting defect state using an electromagnetic pulse of a specified frequency in advance. Specifically, after determining the frequency-length relationship data under the electromagnetic pulse of a specified frequency, the target vibration frequency is substituted into the corresponding frequency-length relationship data to search for the grouting defect length of the channel at the detection position.

[0046] In the above implementation, the target vibration frequency of the steel strand at the detection position under the electromagnetic pulse of the specified frequency is determined based on the frequency interval corresponding to the peak data, and is substituted into the corresponding frequency-length relationship data to calculate the grouting defect length of the duct at the detection position. By quantitatively evaluating the grouting defect length of the duct inside the concrete structure, the grouting defect detection result of the detection position of the duct in the prestressed concrete structure can be obtained more quickly.

[0047] In some embodiments, the frequency-length relationship data is determined in the following manner: searching in a relationship data set according to the pulse frequency of an electromagnetic pulse of a specified frequency, and obtaining relationship data corresponding to the pulse frequency as the frequency-length relationship data.

[0048] The pulse frequency of the electromagnetic pulse of the specified frequency is used to characterize the pulse frequency commonly used or selected depending on the vibration characteristics of the steel strand during the grouting defect detection process. For example, the electromagnetic pulse frequency that is most likely to cause resonance of the steel strand can be taken as the electromagnetic pulse of the specified frequency sent by the electromagnetic excitation device. It is understandable that the pulse frequency of the electromagnetic pulse of the specified frequency can be multiple.

[0049] The relational data set includes the frequency-length relationship data measured at the test position by pre-calibrating vibration detection for the pore model under the grouting defect state using multiple test electromagnetic pulses. Specifically, under multiple test electromagnetic pulses, calibration vibration detection is performed for the pore model under different grouting defect states. The corresponding relationship between the test frequency data and the grouting defect length measured at the test position for the pore model under different grouting defect states under multiple test electromagnetic pulses is obtained, and it can be used as a relational data set. Furthermore, when performing grouting defect detection at the detection position, after determining the pulse frequency of the electromagnetic pulse of the specified frequency, the relational data set is searched according to the pulse frequency of the electromagnetic pulse of the specified frequency, and the pulse frequency of the electromagnetic pulse of the specified frequency is searched and matched with the test electromagnetic pulse during the calibration vibration detection to determine the frequency-length relationship data at the corresponding pulse frequency of the specified frequency.

[0050] In the above implementation, a relational data set for the duct model under different grouting defect states based on multiple test electromagnetic pulses is pre-established. When the grouting defect detection is performed at the detection position, after the pulse frequency of the electromagnetic pulse of the specified frequency is determined, the relational data set is searched according to the pulse frequency of the electromagnetic pulse of the specified frequency, and the pulse frequency of the electromagnetic pulse of the specified frequency is searched and matched with the test electromagnetic pulse during the calibration vibration detection to determine the frequency-length relational data under the pulse frequency of the electromagnetic pulse of the specified frequency. When it is necessary to determine the frequency-length relational data under the specified frequency, it can be directly retrieved from the relational data set, which further improves the efficiency of grouting defect detection at the detection position of the duct.

[0051] In some embodiments, the electromagnetic pulse of the specified frequency includes a plurality of electromagnetic pulses with different pulse frequencies, and the electromagnetic excitation device is used to transmit electromagnetic pulses with different pulse frequencies to the detection position in a step-by-step manner.

[0052] In the above embodiment, the electromagnetic excitation device uses a step-by-step method to emit electromagnetic pulses of different pulse frequencies to the detection position by gradually increasing the frequency. On the one hand, the vibration response of the duct can be detected more carefully and the detection sensitivity can be improved. On the other hand, if a fixed frequency or a jumping frequency change is adopted, some key resonant frequencies may be missed. The step-by-step method can ensure that all possible frequency ranges are covered and omissions are reduced, thereby improving the accuracy and reliability of effective grouting defect detection of ducts in prestressed concrete structures.

[0053] The embodiment of this specification also provides a calibration method for an electromagnetic wave detection device for grouting defects in prestressed ducts of bridges. The electromagnetic wave detection device for grouting defects in prestressed ducts of bridges includes an electromagnetic excitation device and a vibration sensor. The electromagnetic excitation device and the vibration sensor are deployed on the surface of a concrete model. The concrete model has a duct model, and the duct model has grouting material and steel strands. The electromagnetic excitation device is used to emit a test electromagnetic pulse to a test position of the duct model, and the vibration sensor is used to detect the vibration signal caused by the test electromagnetic pulse to the steel strand at the test position. Please refer to the attached Figure 5 , the method comprises the following steps: S510. Determine test vibration time series data of the steel strand based on the vibration signal detected by the vibration sensor.

[0054] Similarly, the test vibration time series data can also be a vibration signal recorded in a time series, which can be used to represent the vibration signal data caused by the resonance generated by the steel strand in the channel model under the concrete model structure when it senses the test electromagnetic pulse emitted by the electromagnetic excitation device. Exemplarily, the electromagnetic pulse frequency that is most likely to cause the steel strand to resonate can be taken as the test electromagnetic pulse sent by the electromagnetic excitation device. Specifically, the electromagnetic excitation device sequentially emits test electromagnetic pulses of a certain frequency to the test position of the channel, and the vibration sensor detects the vibration of the steel strand at the test position due to the electromagnetic pulse and converts it into an electrical signal. Finally, the vibration sensor data time curve under the test electromagnetic pulse is recorded by the data acquisition device, that is, the test vibration time series data of the steel strand at the test position under the test electromagnetic pulse is obtained.

[0055] S520, analyzing the test vibration time series data to obtain test peak data of the test vibration time series data and test frequency data of the steel strand vibrating under the test electromagnetic pulse.

[0056] Similarly, the test peak data may refer to the maximum amplitude data recorded through a time series of the vibration signal generated by the steel strand at the test position when it is subjected to an electromagnetic pulse of a specified frequency and induced to resonate. Exemplarily, the maximum amplitude value of the vibration signal may be used as the test peak data, or a test vibration peak curve drawn when the maximum amplitude value changes with time may be used as the test peak data of the vibration signal. It is also understandable that the test frequency data may refer to the frequency data obtained by analyzing the vibration signal generated by the steel strand at the test position when it is subjected to an electromagnetic pulse and induced to resonate.

[0057] Specifically, the vibration time series data captured by the vibration sensor at the corresponding frequency when the electromagnetic excitation device applies a test electromagnetic pulse to the test position to cause the steel strand to vibrate can be recorded by the data acquisition device. The test peak data at the test position can be extracted by analyzing the time curve of these vibration time series data. Further, the test peak data is analyzed and processed to obtain the test frequency data of the steel strand vibrating under the test electromagnetic pulse at the test position. Exemplarily, the peak points of the vibration data obtained by the test at the test position can be plotted into a test peak curve in time sequence, wherein the abscissa can represent time and the ordinate represents the peak value, and the test peak data of the vibration time series data at the test position can be obtained. Further, the fast Fourier transform (FFT) or short-time Fourier transform (STFT) is applied to the vibration time series data to analyze the frequency component of the vibration signal, and the amplitude of the frequency component is plotted as a test frequency curve with the frequency change, that is, as the test frequency data of the steel strand vibrating under the test electromagnetic pulse at the test position. Among them, the abscissa can represent the frequency and the ordinate represents the amplitude.

[0058] S530. Construct frequency-length relationship data corresponding to the test electromagnetic pulse according to the test peak data and the test frequency data.

[0059] Similarly, the frequency-length relationship data is used to describe the correspondence between the test frequency and the grouting defect length at the test position. Exemplarily, the frequency-length relationship data can be a table or database formed by mapping the test frequency data to the grouting defect length, or it can be a polynomial function with the test frequency data as the independent variable and the grouting defect length as the dependent variable. Specifically, under the test electromagnetic pulse, the pore model under different grouting defect states is calibrated with vibration detection at the test position to obtain the correspondence between the test frequency data and the grouting defect length measured at the test position for the pore model under different grouting defect states.

[0060] In the above implementation, a calibration method for an electromagnetic wave detection device for grouting defects in prestressed ducts of bridges is provided, which can effectively provide a comparison standard for grouting defect detection of ducts in prestressed concrete structures. In particular, when it is necessary to determine the frequency-length relationship data at a specified frequency, the corresponding frequency-length relationship data can be directly searched in the relationship data set according to the pulse frequency of the electromagnetic pulse of the specified frequency, thereby saving time and resources and further improving the efficiency of grouting defect detection of ducts in prestressed concrete structures.

[0061] The embodiment of this specification also provides an electromagnetic wave detection method for grouting defects in prestressed ducts of bridges, Figure 6a This is a schematic diagram of the scenario of this method, such as Figure 6a As shown, a hole 602 is provided in a concrete structure 604. After grouting the hole, the steel strand in the hole includes an area 606 filled with grouting material and an empty area 608 not filled with grouting material. An electromagnetic excitation device 610 and a vibration sensor 612 are deployed on the surface of the concrete structure. The electromagnetic excitation device 610 is used to transmit an electromagnetic pulse of a specified frequency to the detection position of the hole, and the vibration sensor 612 is used to detect the vibration signal caused by the electromagnetic pulse of the specified frequency to the steel strand at the detection position. The controller 614 is connected to a data acquisition device, and the controller 614 is connected to the electromagnetic excitation device 610 and the vibration sensor 612 respectively. Figure 6b is a flow chart of an electromagnetic wave detection method for grouting defects in prestressed ducts of bridges provided by the implementation mode of this specification in the above scenario, such as Figure 6b As shown, the method comprises the following steps: S602. Determine vibration time series data of the steel strand based on the vibration signal detected by the vibration sensor.

[0062] S604, analyzing the vibration time series data to obtain detection peak data of the vibration time series data and detection frequency data of the steel strand vibrating under an electromagnetic pulse of a specified frequency.

[0063] The electromagnetic pulse of the specified frequency includes a plurality of electromagnetic pulses with different pulse frequencies, and the electromagnetic excitation device is used to transmit electromagnetic pulses with different pulse frequencies to the detection position in a step-by-step manner in an increasing manner from small to large.

[0064] S606: When the detection peak data is less than the first calibration peak data, determine that the detection position is in a fully grouting state.

[0065] The first calibration peak data is determined in advance by using an electromagnetic pulse of a specified frequency to perform vibration detection on a pore model in a fully grouted state.

[0066] S608: Determine a target frequency interval in a frequency range corresponding to the detected frequency data.

[0067] S610, performing mean calculation according to the target frequency interval to obtain the target vibration frequency of the steel strand under the electromagnetic pulse of the specified frequency.

[0068] S612. Search the frequency-length relationship data according to the target vibration frequency to obtain the grouting defect length at the detection position.

[0069] The frequency-length relationship data is the correspondence between the test frequency and the grouting defect length determined in advance by using an electromagnetic pulse of a specified frequency to perform vibration detection on the channel model in the grouting defect state.

[0070] S614: When there is excess peak data greater than the second calibration peak data in the detected peak data, determine a frequency interval corresponding to the excess peak data.

[0071] The second calibration peak data is determined in advance by performing vibration detection on the pore model in the grouting defect state using electromagnetic pulses of a specified frequency.

[0072] S616. Perform mean calculation based on the frequency interval corresponding to the peak value data to obtain the target vibration frequency of the steel strand under the electromagnetic pulse of the specified frequency.

[0073] S618. Search the relational data set according to the pulse frequency of the electromagnetic pulse of the specified frequency to obtain relational data corresponding to the pulse frequency as frequency-length relational data.

[0074] The relationship data set includes frequency-length relationship data determined in advance by performing vibration detection on the pore model in the grouting defect state using multiple test electromagnetic pulses.

[0075] S620, searching in the frequency-length relationship data according to the target vibration frequency to obtain the grouting defect length at the detection position.

[0076] It should be understood that, although the various steps in the above flowchart are displayed in sequence according to the indication of the arrows, these steps are not necessarily executed in sequence according to the order indicated by the arrows. Unless there is a clear description in this article, there is no strict order restriction on the execution of these steps, and these steps can be executed in other orders. Moreover, at least a part of the steps in the above flowchart may include multiple steps or multiple stages, and these steps or stages are not necessarily executed at the same time, but can be executed at different times, and the execution order of these steps or stages is not necessarily to be carried out in sequence, but can be executed in turn or alternately with other steps or at least a part of the steps or stages in other steps.

[0077] The embodiment of this specification also provides an electromagnetic wave detection device 700 for grouting defects in prestressed bridge channels. The channels are arranged in a concrete structure. Grouting materials and steel strands are arranged in the channels. An electromagnetic excitation device and a vibration sensor are deployed on the surface of the concrete structure. The electromagnetic excitation device is used to transmit electromagnetic pulses of a specified frequency to the detection position of the channel. The electromagnetic pulses of the specified frequency include multiple electromagnetic pulses with different pulse frequencies. The electromagnetic excitation device is used to use a step-by-step method to transmit electromagnetic pulses with different pulse frequencies to the detection position in a manner of increasing from small to large. The vibration sensor is used to detect the vibration signal caused by the electromagnetic pulse of the specified frequency on the steel strands at the detection position. Figure 7 As shown, the device may include: a vibration data determination module 710, a peak frequency analysis module 720 and a grouting defect detection module 730, wherein: The vibration data determination module 710 is used to determine the vibration time series data of the steel strand based on the vibration signal detected by the vibration sensor.

[0078] The peak frequency analysis module 720 is used to analyze the vibration time series data to obtain the detection peak data of the vibration time series data and the detection frequency data of the steel strand vibrating under the electromagnetic pulse of the specified frequency.

[0079] The grouting defect detection module 730 is used to perform grouting defect detection on the detection position according to the detection peak data and / or the detection frequency data to obtain the grouting defect detection result of the detection position.

[0080] In some embodiments, the grouting defect detection module 730 is also used to determine that the detection position is in a full grouting state when the detection peak data is less than the first calibration peak data, wherein the first calibration peak data is pre-determined by vibration detection of the pore model in the full grouting state using an electromagnetic pulse of a specified frequency.

[0081] In some embodiments, the grouting defect detection module 730 is further used to determine a target frequency interval in the frequency range corresponding to the detection frequency data. The mean value is calculated according to the target frequency interval to obtain the target vibration frequency of the steel strand under the electromagnetic pulse of the specified frequency. The frequency-length relationship data is searched according to the target vibration frequency to obtain the grouting defect length at the detection position. Among them, the frequency-length relationship data is the correspondence between the test frequency and the grouting defect length determined by performing vibration detection on the channel model under the grouting defect state using the electromagnetic pulse of the specified frequency in advance.

[0082] In some embodiments, the grouting defect detection module 730 is further used to determine the frequency interval corresponding to the exceeding peak data when there is exceeding peak data greater than the second calibration peak data in the detection peak data, wherein the second calibration peak data is determined in advance by vibration detection of the duct model in the grouting defect state using a specified frequency electromagnetic pulse. The grouting defect length at the detection position is determined according to the frequency interval corresponding to the exceeding peak data and the frequency-length relationship data, wherein the frequency-length relationship data is the corresponding relationship between the test frequency and the grouting defect length determined in advance by vibration detection of the duct model in the grouting defect state using a specified frequency electromagnetic pulse.

[0083] In some embodiments, the grouting defect detection module 730 is further used to determine the grouting defect length at the detection position according to the frequency interval corresponding to the exceeded peak data and the frequency-length relationship data, including: performing mean calculation according to the frequency interval corresponding to the exceeded peak data to obtain the target vibration frequency of the steel strand under the electromagnetic pulse of the specified frequency. Searching in the frequency-length relationship data according to the target vibration frequency to obtain the grouting defect length at the detection position.

[0084] In some embodiments, the electromagnetic wave detection device 700 for grouting defects in prestressed bridge ducts also includes a frequency-length relationship determination module, which is used to search in a relationship data set according to the pulse frequency of an electromagnetic pulse of a specified frequency, and obtain relationship data corresponding to the pulse frequency as frequency-length relationship data, wherein the relationship data set includes frequency-length relationship data determined in advance by performing vibration detection on a duct model in a grouting defect state using multiple test electromagnetic pulses.

[0085] The specific definition of an electromagnetic wave detection device for grouting defects in prestressed ducts of bridges can be found in the above definition of an electromagnetic wave detection method for grouting defects in prestressed ducts of bridges, which will not be repeated here. Each module in the above electromagnetic wave detection device for grouting defects in prestressed ducts of bridges can be implemented in whole or in part by software, hardware, and a combination thereof.

[0086] The embodiment of the present specification also provides a bridge prestressed channel grouting defect electromagnetic wave detection calibration device 800, the bridge prestressed channel grouting defect electromagnetic wave detection device includes an electromagnetic excitation device and a vibration sensor, the electromagnetic excitation device and the vibration sensor are deployed on the surface of a concrete model, the concrete model has a channel model, the channel model has grouting material and steel strands, the electromagnetic excitation device is used to emit a test electromagnetic pulse to the test position of the channel model, and the vibration sensor is used to detect the vibration signal caused by the test electromagnetic pulse to the steel strand at the test position. Figure 8 As shown, it includes: a test vibration data determination module 810, a test frequency determination module 820 and a frequency-length relationship determination module 830, wherein: The test vibration data determination module 810 is used to determine the test vibration time series data of the steel strand based on the vibration signal detected by the vibration sensor.

[0087] The test frequency determination module 820 is used to analyze the test vibration time series data to obtain the test peak value data of the test vibration time series data and the test frequency data of the steel strand vibrating under the test electromagnetic pulse.

[0088] The frequency-length relationship determination module 830 is used to construct the frequency-length relationship data corresponding to the test electromagnetic pulse according to the test peak data and the test frequency data, wherein the frequency-length relationship data is used to describe the corresponding relationship between the test frequency and the length of the grouting defect at the test position.

[0089] Regarding the specific definition of an electromagnetic wave detection and calibration device for grouting defects in prestressed ducts of bridges, please refer to the definition of an electromagnetic wave calibration method for detecting defects in prestressed ducts of bridges in the above text, which will not be repeated here. Each module in the above-mentioned electromagnetic wave detection and calibration device for grouting defects in prestressed ducts of bridges can be fully or partially implemented by software, hardware and a combination thereof. The above-mentioned modules can be embedded in or independent of the processor in the computer device in the form of hardware, or can be stored in the memory of the computer device in the form of software, so that the processor can call and execute the operations corresponding to the above-mentioned modules.

[0090] The present specification also provides a bridge prestressed channel grouting defect electromagnetic wave detection device 900, such as Fig. 9 As shown, it includes: an electromagnetic excitation device 910, a vibration sensor 920, a data acquisition device 930, and a controller 940. The electromagnetic excitation device 910 and the vibration sensor 920 are respectively used to be deployed on the surface of a concrete structure, and a grouting material and a steel strand are provided in a hole in the concrete structure. The controller 940 is respectively connected to the electromagnetic excitation device 910 and the vibration sensor 920, and the vibration sensor 920 is connected to the data acquisition device 930.

[0091] The electromagnetic excitation device 910 is used to emit a test electromagnetic pulse to the detection position of the hole.

[0092] The vibration sensor 920 is used to detect the vibration signal caused by the test electromagnetic pulse on the steel strand at the test position.

[0093] The data acquisition device 930 is used to determine the vibration time series data of the steel strand based on the vibration signal detected by the vibration sensor.

[0094] The controller 940 is used to perform grouting defect detection on the detection position according to the vibration time series data to obtain the grouting defect detection result of the detection position.

[0095] In this embodiment, an electromagnetic wave detection device for grouting defects in prestressed ducts of bridges is presented in the form of a functional unit, where the unit refers to an ASIC (Application Specific Integrated Circuit) circuit, a processor and memory that executes one or more software or fixed programs, and / or other devices that can provide the above-mentioned functions.

[0096] The embodiment of the present application also provides a computer device, which may be a terminal, and its internal structure diagram may be as follows: Fig.10 As shown. The computer device includes a processor, a memory, a communication interface, a display screen and an input device connected through a system bus. Among them, the processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and a computer program. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The communication interface of the computer device is used to communicate with an external terminal in a wired or wireless manner, and the wireless manner can be achieved through WIFI, a mobile cellular network, NFC (near field communication) or other technologies. When the computer program is executed by the processor, an electromagnetic wave detection method for grouting defects in prestressed ducts of bridges is implemented. The display screen of the computer device can be a liquid crystal display screen or an electronic ink display screen, and the input device of the computer device can be a touch layer covered on the display screen, or a key, trackball or touchpad set on the computer device shell, or an external keyboard, touchpad or mouse.

[0097] The embodiment of the present application also provides a computer-readable storage medium. The above method according to the embodiment of the present application can be implemented in hardware, firmware, or implemented as a computer code that can be recorded in a storage medium, or is implemented as a computer code that is originally stored in a remote storage medium or a non-temporary machine-readable storage medium and will be stored in a local storage medium through a network download, so that the method described herein can be stored in such software processing on a storage medium using a general-purpose computer, a dedicated processor, or programmable or dedicated hardware. Among them, the storage medium can be a magnetic disk, an optical disk, a read-only storage memory, a random access memory, a flash memory, a hard disk or a solid-state hard disk, etc.; further, the storage medium can also include a combination of the above types of memories. It can be understood that a computer, a processor, a microprocessor controller, or programmable hardware includes a storage component that can store or receive software or computer code. When the software or computer code is accessed and executed by a computer, a processor, or hardware, the method shown in the above embodiment is implemented.

[0098] The embodiment of the present application provides a computer program product, which includes computer instructions, which are stored in a computer-readable storage medium. The processor of the computer device reads the computer instructions from the computer-readable storage medium, and the processor executes the computer instructions, so that the computer device executes the method of any embodiment of the present application. The electromagnetic wave detection method and device for grouting defects in prestressed ducts of bridges described in the above embodiment can be implemented by a computer chip or entity, or by a product with a certain function. A typical implementation device is a computer. Specifically, the computer can be, for example, a personal computer, a laptop computer, a cellular phone, a camera phone, a smart phone, a personal digital assistant, a media player, a navigation device, an email device, a game console, a tablet computer, a wearable device, or a combination of any of these devices. For the convenience of description, the above device is described in terms of functions and is described separately in various units. Of course, when implementing this application, the functions of each unit can be implemented in the same one or more software and / or hardware.

[0099] Those skilled in the art should understand that the embodiments of the present application can be provided as methods, systems, or computer program products. Therefore, the present application can take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present application can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code. The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices, and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the process Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0100] In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, the features defined as "first" and "second" can explicitly or implicitly include at least one of the features. In the description of this application, the meaning of "multiple" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined. It should also be noted that the terms "including" and "comprising" or any other variants thereof are intended to cover non-exclusive inclusion, so that the process, method, commodity or equipment including a series of elements includes not only those elements, but also other elements that are not explicitly listed, or also includes elements inherent to such process, method, commodity or equipment. In the absence of more restrictions, the elements defined by the sentence "including one..." do not exclude the existence of other identical elements in the process, method, commodity or equipment including the elements.

[0101] 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, and each embodiment focuses on the differences from other embodiments. In particular, for the computer device, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment.

[0102] The above are only embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various changes and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included within the scope of the claims of the present application.

[0103] Although the embodiments of the present application are described in conjunction with the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present application, and such modifications and variations are all within the scope defined by the appended claims.

Claims

1. An electromagnetic wave detection method for grouting defects in prestressed ducts of bridges, characterized in that: The hole is provided in a concrete structure, and grouting material and steel strands are provided in the hole. An electromagnetic excitation device and a vibration sensor are arranged on the surface of the concrete structure; the electromagnetic excitation device is used to transmit an electromagnetic pulse of a specified frequency to a detection position of the hole, and the vibration sensor is used to detect a vibration signal caused by the electromagnetic pulse of the specified frequency to the steel strands at the detection position; the method comprises: Determining vibration time series data of the steel strand based on the vibration signal detected by the vibration sensor; Analyzing the vibration time series data to obtain detection peak data of the vibration time series data and detection frequency data of the steel strand vibrating under the electromagnetic pulse of the specified frequency; The grouting defect detection is performed on the detection position according to the detection peak data and / or the detection frequency data to obtain the grouting defect detection result of the detection position.

2. The method according to claim 1, characterized in that The performing grouting defect detection on the detection position according to the detection peak data and / or the detection frequency data to obtain the grouting defect detection result of the detection position includes: When the detection peak data is less than the first calibration peak data, it is determined that the detection position is in a fully grouting state; wherein, the first calibration peak data is determined in advance by performing vibration detection on the channel model in the fully grouting state using the electromagnetic pulse of the specified frequency.

3. The method according to claim 1, characterized in that The performing grouting defect detection on the detection position according to the detection peak data and / or the detection frequency data to obtain the grouting defect detection result of the detection position includes: Determine a target frequency interval in the frequency range corresponding to the detection frequency data; Performing mean value calculation according to the target frequency interval to obtain the target vibration frequency of the steel strand under the electromagnetic pulse of the specified frequency; The frequency-length relationship data is searched according to the target vibration frequency to obtain the grouting defect length at the detection position; wherein the frequency-length relationship data is the correspondence between the test frequency and the grouting defect length determined in advance by performing vibration detection on the channel model in the grouting defect state using the electromagnetic pulse of the specified frequency.

4. The method according to claim 1, characterized in that: The performing grouting defect detection on the detection position according to the detection peak data and / or the detection frequency data to obtain the grouting defect detection result of the detection position includes: In the case where there is an excess peak data greater than the second calibration peak data in the detection peak data, determining a frequency interval corresponding to the excess peak data; wherein the second calibration peak data is determined in advance by performing vibration detection on the pore model in the grouting defect state using the electromagnetic pulse of the specified frequency; The grouting defect length at the detection position is determined based on the frequency range corresponding to the exceeding peak data and the frequency-length relationship data; wherein the frequency-length relationship data is the correspondence between the test frequency and the grouting defect length determined in advance by performing vibration detection on the channel model under the grouting defect state using the electromagnetic pulse of the specified frequency.

5. The method according to claim 4, characterized in that The determining of the grouting defect length at the detection position according to the frequency interval corresponding to the exceeding peak value data and the frequency-length relationship data comprises: Performing mean calculation according to the frequency interval corresponding to the exceeding peak value data to obtain the target vibration frequency of the steel strand vibrating under the electromagnetic pulse of the specified frequency; The frequency-length relationship data is searched according to the target vibration frequency to obtain the grouting defect length at the detection position.

6. The method according to claim 4, characterized in that The frequency-length relationship data is determined by: According to the pulse frequency of the electromagnetic pulse of the specified frequency, the relational data set is searched to obtain the relational data corresponding to the pulse frequency as the frequency-length relational data; wherein the relational data set includes the frequency-length relational data determined in advance by vibration detection of the pore model under the grouting defect state using multiple test electromagnetic pulses.

7. The method according to claim 1, characterized in that The electromagnetic pulse of the specified frequency includes a plurality of electromagnetic pulses with different pulse frequencies; the electromagnetic excitation device is used to transmit electromagnetic pulses with different pulse frequencies to the detection position in a step-by-step manner.

8. A calibration method for an electromagnetic wave detection device for grouting defects in prestressed ducts of bridges, characterized in that: The electromagnetic wave detection device for grouting defects of prestressed ducts of bridges comprises an electromagnetic excitation device and a vibration sensor; the electromagnetic excitation device and the vibration sensor are deployed on the surface of a concrete model, the concrete model comprises a duct model, the duct model comprises grouting material and steel strands, the electromagnetic excitation device is used to emit a test electromagnetic pulse to a test position of the duct model, and the vibration sensor is used to detect a vibration signal caused by the test electromagnetic pulse to the steel strand at the test position; the method comprises: Determining test vibration time series data of the steel strand based on the vibration signal detected by the vibration sensor; Analyzing the test vibration time series data to obtain test peak value data of the test vibration time series data and test frequency data of the steel strand vibrating under the test electromagnetic pulse; The frequency-length relationship data corresponding to the test electromagnetic pulse is constructed according to the test peak data and the test frequency data; wherein the frequency-length relationship data is used to describe the corresponding relationship between the test frequency and the grouting defect length at the test position.

9. An electromagnetic wave detection device for grouting defects in prestressed ducts of bridges, characterized in that: The hole is arranged in a concrete structure, and grouting material and steel strands are arranged in the hole. An electromagnetic excitation device and a vibration sensor are arranged on the surface of the concrete structure; the electromagnetic excitation device is used to transmit an electromagnetic pulse of a specified frequency to a detection position of the hole, and the vibration sensor is used to detect a vibration signal caused by the electromagnetic pulse of the specified frequency to the steel strands at the detection position; the device comprises: A vibration data determination module, used to determine the vibration time series data of the steel strand based on the vibration signal detected by the vibration sensor; A peak frequency analysis module, used for analyzing the vibration time series data to obtain detection peak data of the vibration time series data and detection frequency data of the steel strand vibrating under the electromagnetic pulse of the specified frequency; The grouting defect detection module is used to perform grouting defect detection on the detection position according to the detection peak data and / or the detection frequency data to obtain the grouting defect detection result of the detection position.

10. An electromagnetic wave detection device for grouting defects in prestressed ducts of bridges, characterized in that: The electromagnetic wave detection device for grouting defects in prestressed ducts of bridges comprises a controller, a data acquisition device, an electromagnetic excitation device and a vibration sensor; the electromagnetic excitation device and the vibration sensor are respectively used to be deployed on the surface of a concrete structure, and the ducts in the concrete structure have grouting materials and steel strands; the controller is respectively connected to the electromagnetic excitation device and the vibration sensor, and the vibration sensor is connected to the data acquisition device; The electromagnetic excitation device is used to emit a test electromagnetic pulse to the detection position of the hole; The vibration sensor is used to detect the vibration signal caused by the test electromagnetic pulse on the steel strand at the detection position; The data acquisition device is used to determine the vibration time series data of the steel strand based on the vibration signal detected by the vibration sensor; The controller is used to perform grouting defect detection on the detection position according to the vibration time series data to obtain a grouting defect detection result of the detection position.

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