Frequency domain ground penetrating radar pipe leakage detection method and system

Abstract

The invention discloses a frequency domain ground penetrating radar pipe leakage detection method and system, and relates to the technical field of pipeline leakage detection, and the method comprises the steps: employing a frequency domain ground penetrating radar to carry out the whole pipe segment detection of a pipeline, and obtaining an original electromagnetic wave signal; preprocessing the original electromagnetic wave signal to obtain an echo signal; extracting time-frequency domain features of the echo signals, and screening the time-frequency domain features; identifying the screened time-frequency domain features by using a leakage identification model to obtain suspected leakage pipe sections; starting a microwave impedance measuring device at the position of the suspected leakage pipe section to obtain a reflection signal; and determining the axial position and the radial position of the leakage point according to the reflection signal. According to the method, the frequency domain ground penetrating radar is adopted for primary screening of the whole pipe section, after the suspected leakage pipe section is recognized, the microwave impedance technology is utilized for fine recognition, the wire for impedance measurement is only arranged in the high-risk pipe section, construction and use convenience is improved, and meanwhile the precision of the detection result is improved.

Description

Technical Field

[0001] This application relates to the field of pipeline leakage detection technology, and in particular to the technology of using frequency domain ground penetrating radar for pipeline leakage detection. Background Technology

[0002] Pipelines transporting liquids such as tap water and sewage are typically buried beneath roads. After backfilling, vegetation can be planted or the road surface paved, without affecting its function. However, because the liquids inside these pipes are under pressure, and after prolonged use, leaks may occur at weak points. Leaks not only disrupt the normal transport of water but can also erode the underground soil, potentially leading to serious consequences such as road collapse. Therefore, proactively detecting leaks can minimize their impact.

[0003] Since the location of leaks cannot be predicted in advance, non-contact detection methods are currently the most common. Two common methods are ground-penetrating radar (GPR), such as CN119780910A, and microwave impedance detection, such as CN120101057A. The former uses frequency-domain GPR to collect and identify the echo signals generated by leaks, and it has no requirements for the pipe, making it relatively convenient to implement. However, the detection results cannot clearly indicate the precise location. The latter requires pre-wrapping wires around the outside of the pipe; although it can indicate axial and radial positions, it is more complex to implement and more expensive.

[0004] Therefore, it is necessary to provide a pipe leak detection method that is both convenient and has high positional accuracy. Summary of the Invention

[0005] This application provides a frequency domain ground-penetrating radar tube leakage detection method and system to solve the problems of low positioning accuracy and inconvenient implementation in the prior art.

[0006] On one hand, embodiments of this application provide a method for detecting leaks in a frequency-domain ground-penetrating radar tube, including: Frequency domain ground-penetrating radar is used to detect the entire pipeline section and obtain the original electromagnetic wave signal; The original electromagnetic wave signal is preprocessed to obtain the echo signal; Extract the time-frequency domain features of the echo signal and then filter these features. The leakage identification model is used to identify the time-frequency domain features after screening, and suspected leakage pipe sections are obtained. The microwave impedance measurement device at the suspected leaking pipe section is activated to obtain the reflected signal. The microwave impedance measurement device includes a control unit and a detection lead wire. The detection lead wire is sleeved on the high-risk pipe section. The high-risk pipe section is the pipe section whose leakage risk value exceeds the risk threshold after the leakage risk value of the pipe is assessed. The axial and radial positions of the leak point are determined based on the reflected signals.

[0007] On the other hand, embodiments of this application also provide a frequency domain ground-penetrating radar tube leakage detection system, including: Frequency domain ground-penetrating radar is used to detect the entire pipeline section and obtain the raw electromagnetic wave signal. The data processing device is used to preprocess the original electromagnetic wave signal to obtain the echo signal; extract the time-frequency domain features of the echo signal and filter the time-frequency domain features; and use the leakage identification model to identify the filtered time-frequency domain features to obtain the suspected leakage pipe section. A microwave impedance measurement device is used to acquire the reflected signal of a suspected leaking pipe section. The microwave impedance measurement device includes a control unit and a detection lead wire. The detection lead wire is sleeved on a high-risk pipe section. The high-risk pipe section is a pipe section in which the leakage risk value exceeds the risk threshold after the leakage risk value of the pipe is assessed. The data processing device is also used to determine the axial and radial positions of the leak point based on the reflected signal.

[0008] The frequency domain ground-penetrating radar tube leakage detection method and system disclosed in this application have the following advantages: By combining frequency domain ground-penetrating radar (FPR) and microwave impedance technology, FPR is used for initial screening of the entire pipe section to identify suspected leaking sections. Then, microwave impedance technology is used for fine identification. Moreover, the wires used in microwave impedance identification are only placed in high-risk sections of the pipeline, without needing to be laid throughout the entire pipe section, which greatly improves the convenience of construction and use, and also improves the accuracy of the detection results. Attached Figure Description

[0009] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0010] Figure 1 A flowchart of a frequency domain ground-penetrating radar tube leakage detection method provided in an embodiment of this application. Detailed Implementation

[0011] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0012] Figure 1 A flowchart illustrating a frequency-domain ground-penetrating radar tube leakage detection method provided in this application embodiment. This application embodiment provides a frequency-domain ground-penetrating radar tube leakage detection method, including: S100 uses frequency domain ground-penetrating radar to detect the entire pipeline section and obtain the original electromagnetic wave signal.

[0013] For example, before detection, the movement route of the frequency domain ground penetrating radar needs to be pre-set along the direction of the pipeline. Then, the frequency domain ground penetrating radar is moved along the movement route by hand or vehicle, and the raw electromagnetic wave signals are collected simultaneously. S raw ( t ).

[0014] S110 preprocesses the original electromagnetic wave signal to obtain the echo signal. S echo ( t ).

[0015] For example, the preprocessing of the original electromagnetic wave signal includes sequential DC drift removal, static correction, bandpass filtering, and mean smoothing.

[0016] Specifically, DC drift removal eliminates signal baseline offset, static correction removes interference from direct air waves, bandpass filtering uses a Butterworth bandpass filter, and mean smoothing processes the signal after bandpass filtering.

[0017] S120: Extract the time-frequency domain features of the echo signal and filter the time-frequency domain features.

[0018] For example, time-frequency domain features include amplitude statistics, frequency domain properties, and dielectric constant-related features.

[0019] Specifically, the amplitude statistical properties and frequency domain properties are disclosed in CN119780910A, and will not be repeated here. The dielectric constant correlation feature is specifically the amplitude of the dielectric constant abrupt change, which is the result of dividing the difference between the maximum and minimum amplitude values ​​of all sampling points by the average amplitude.

[0020] The screening of time-frequency domain features involves two stages: random forest screening and PCA (principal component analysis) screening, to obtain effective features. Eeff These methods are also disclosed in CN119780910A, and will not be repeated in the embodiments of this application.

[0021] S130 uses a leakage identification model to identify the time-frequency domain features after screening, and obtains suspected leakage pipe sections.

[0022] For example, the leakage identification model is built on a BP (backpropagation) neural network.

[0023] This leakage detection model needs to be trained and validated before use, and then the effective features will be used. E eff Input the leakage identification model and output the pipe segment number of the suspected leakage segment.

[0024] S140, activate the microwave impedance measurement device at the location of the suspected leaking pipe section to obtain the reflected signal. The microwave impedance measurement device includes a control unit and a detection lead wire. The detection lead wire is sleeved on the high-risk pipe section. The high-risk pipe section is the pipe section in which the leakage risk value exceeds the risk threshold after the leakage risk value of the pipe is assessed.

[0025] For example, the method for assessing the leakage risk value of a pipeline and identifying high-risk pipeline sections is as follows: Collect environmental parameters of the pipeline's burial location and structural parameters of the pipeline; Environmental and structural parameters are quantified to obtain corresponding environmental and structural index values. The leakage risk value of each pipe section is calculated by combining environmental and structural indicator values ​​with their corresponding weights. The leakage risk value of each pipe segment is compared with the preset risk threshold, and the pipe segments with leakage risk values ​​greater than the risk threshold are identified as high-risk pipe segments.

[0026] Specifically, before laying the water pipeline, basic physical parameters of the pipeline and its location can be collected in advance to provide data support for subsequent risk assessment. These basic physical parameters include environmental and structural parameters. Environmental parameters include soil corrosion level, groundwater level, and road surface hardening level, while structural parameters include pipeline design pressure, pipeline wall thickness, and pipeline material. See Table 1 for details.

[0027] Table 1. Basic physical parameters of pipelines and their installation locations.

[0028] Based on the basic physical parameters collected above, the leakage risk value of each pipe section is calculated using the weighted factor method to classify high, medium and low risk pipe sections.

[0029] Before calculating the leakage risk value, five indicators need to be selected, including three environmental indicators and two structural indicators. The environmental indicators include soil corrosion risk. R c Risks related to groundwater level R w and road hardening grade R l The structural index values ​​include the pipeline structural strength risk. R s Risk of pipe material aging R m Among them, the risk of groundwater level impact R w Take groundwater level H g The reciprocal of the pipeline structure strength risk R s Then take the pipeline design pressure. P d and pipe wall thickness t p The ratio of .

[0030] Soil corrosion risk R c According to soil corrosion level C s Values ​​can be obtained, for example, by directly using R c Pick C s Value, risk of pipe material aging R m According to the pipe material M p For example, when the pipe material is PVC (polyvinyl chloride) or PE (polyethylene), R m Take 1, when the pipe material is ductile iron. R m Take 2, when the pipe material is steel pipe. R m Take 3.

[0031] Next, the weighted summation of the above 5 indicator values ​​is used to calculate the first... k Leakage risk value of each pipe section R total,k In the weighted summation process, soil corrosivity risk R c Pipeline structural strength risk R s Risks related to groundwater level R w Risk of pipe material aging Rm and road hardening grade R l The weights are 0.3, 0.25, 0.2, 0.15, and 0.1, respectively. When dividing the pipe into segments, the entire pipeline can be divided into segments starting from one end according to a set unit length, such as 10m. Each unit length is a pipe segment.

[0032] Pipe sections with a leakage risk value greater than or equal to 3.5 can be classified as high-risk pipe sections, pipe sections with a leakage risk value greater than 2.0 but less than 3.5 can be classified as medium-risk pipe sections, and pipe sections with a leakage risk value less than or equal to 2.0 can be classified as low-risk pipe sections.

[0033] After identifying high-risk pipe sections, detection leads can be installed on the outside of these sections. By first assessing the leakage risk and then installing detection leads only on high-risk sections, the number of detection leads used can be effectively reduced, thereby lowering system costs and improving operational convenience.

[0034] Before installing the inspection guide wire, the key parameters of the inspection guide wire need to be calculated. This is based on the outer diameter of the pipe. D p It can be combined with the pitch A The length of a single turn of the detection wire was calculated. l and the total length of the inspection wires covering a single high-risk pipe section L w It can also obtain the diameter of the detection wire. d w and the dielectric constant of the insulating layer ε w .

[0035] After calculating or collecting the above parameters, you can prepare to install the test leads. The installation process is as follows: (1) Clean the outer surface of high-risk pipe sections to remove oil and impurities; (2) According to pitch A The detection wire is spirally wound around the outside of the pipe and fixed with high-temperature resistant clips to prevent the detection wire from shifting during installation. (3) A 1m extension section is reserved at both ends of each test lead for subsequent connection with the coaxial multiplexer in the microwave impedance measurement device. The extension section of the test lead needs to be wrapped with an anti-corrosion sleeve. (4) Record the pipe section number and wire parameters of the pre-installed test wires on each pipe section for subsequent test data interpretation.

[0036] After installing the test leads, the control unit in the microwave impedance measurement device can be installed next. This control unit is the microwave impedance measurement circuit in CN120101057A. In addition, the microwave impedance measurement device in this embodiment of the application also includes a coaxial multiplexer, a data collector and a wireless data transmission module. The connection relationship of these modules can be referred to CN120101057A, and will not be repeated here.

[0037] Furthermore, in this embodiment of the application, all components of the microwave impedance measuring device except for the detection wire are installed in the equipment box, which is installed on a concrete base near the pipeline, and each high-risk pipe section is equipped with a corresponding microwave impedance measuring device.

[0038] S150, determine the axial and radial positions of the leakage point based on the reflected signal.

[0039] For example, determining the axial and radial positions of the leakage point based on the reflected signal includes: Extract the time parameter from the reflected signal, including the time it takes for the signal to reflect from the starting end of the detection wire. T start The time it takes for the signal to be reflected from the end of the detection wire T end And the time it takes for the signal to reflect at the leak point. T Leakage ; The location of the leak point on the detection lead was determined based on the time parameters. :

[0040] in, L w To detect the total length of the wire.

[0041] The axial position of the leak point on the pipe is determined by the location of the leak point on the detection wire, the pitch of the detection wire wound on the pipe, and the length of a single turn. Y :

[0042] The radial position of the leak point on the pipe is determined by the location of the leak point on the detection guide and the length of a single turn of the detection guide. θ :

[0043] Here, % represents the remainder symbol.

[0044] This application embodiment also provides a frequency domain ground-penetrating radar tube leakage detection system, the system comprising: Frequency domain ground-penetrating radar is used to detect the entire pipeline section and obtain the raw electromagnetic wave signal. The data processing device is used to preprocess the original electromagnetic wave signal to obtain the echo signal; extract the time-frequency domain features of the echo signal and filter the time-frequency domain features; and use the leakage identification model to identify the filtered time-frequency domain features to obtain the suspected leakage pipe section. A microwave impedance measurement device is used to acquire the reflected signal of a suspected leaking pipe section. The microwave impedance measurement device includes a control unit and a detection lead wire. The detection lead wire is sleeved on a high-risk pipe section. The high-risk pipe section is a pipe section in which the leakage risk value exceeds the risk threshold after the leakage risk value of the pipe is assessed. The data processing device is also used to determine the axial and radial positions of the leak point based on the reflected signal.

[0045] For example, the microwave impedance measurement device also includes a battery and a solar panel. Each high-risk pipe section is equipped with a microwave impedance measurement device. The solar panel is used to charge the battery, and the battery is used to power the control unit.

[0046] Both the frequency domain ground-penetrating radar and the microwave impedance measurement device are connected to the data processing device via wireless communication.

[0047] Although preferred embodiments of this application have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of this application.

[0048] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of this application. Therefore, if such modifications and variations fall within the scope of the claims of this application and their equivalents, this application also intends to include such modifications and variations.

Claims

1. A method for detecting leaks in a frequency-domain ground-penetrating radar tube, characterized in that, include: Frequency domain ground-penetrating radar is used to detect the entire pipeline section and obtain the original electromagnetic wave signal; The original electromagnetic wave signal is preprocessed to obtain the echo signal; Extract the time-frequency domain features of the echo signal, and then filter the time-frequency domain features; The leakage identification model is used to identify the time-frequency domain features after screening to obtain suspected leakage pipe sections; The microwave impedance measurement device at the location of the suspected leaking pipe section is activated to obtain the reflected signal. The microwave impedance measurement device includes a control unit and a detection wire. The detection wire is sleeved on the high-risk pipe section of the pipeline. The high-risk pipe section is the pipe section in the pipeline whose leakage risk value exceeds the risk threshold after the leakage risk value of the pipeline is assessed. The axial and radial positions of the leakage point are determined based on the reflected signal.

2. The method for detecting leakage in a frequency-domain ground-penetrating radar tube according to claim 1, characterized in that, The method for assessing the leakage risk value of pipelines and identifying the high-risk pipeline sections is as follows: Collect environmental parameters of the pipeline's burial location and structural parameters of the pipeline; The environmental parameters and structural parameters are quantified to obtain corresponding environmental index values ​​and structural index values. The leakage risk value of each pipe segment is calculated by combining the environmental index value, the structural index value, and the corresponding weights. The leakage risk value of each pipe segment is compared with a preset risk threshold, and the pipe segments with leakage risk values ​​greater than the risk threshold are designated as high-risk pipe segments.

3. The method for detecting leakage in a frequency-domain ground-penetrating radar tube according to claim 2, characterized in that, The environmental parameters include soil corrosion level, groundwater level and road surface hardening level, and the structural parameters include pipeline design pressure, pipeline wall thickness and pipeline material.

4. The method for detecting leakage in a frequency-domain ground-penetrating radar tube according to claim 1, characterized in that, The preprocessing of the original electromagnetic wave signal includes DC drift removal, static correction, bandpass filtering, and mean smoothing.

5. The method for detecting leakage in a frequency-domain ground-penetrating radar tube according to claim 1, characterized in that, The time-frequency domain features include amplitude statistical properties, frequency domain properties, and dielectric constant correlation features.

6. The method for detecting leakage in a frequency-domain ground-penetrating radar tube according to claim 1, characterized in that, The leakage identification model is built based on a BP neural network.

7. The method for detecting leakage in a frequency-domain ground-penetrating radar tube according to claim 1, characterized in that, Determining the axial and radial positions of the leakage point based on the reflected signal includes: Extract the time parameters from the reflected signal, including the time it takes for the signal to be reflected from the beginning of the detection wire, the time it takes for the signal to be reflected from the end of the detection wire, and the time it takes for the signal to be reflected at the leak point; The location of the leak point on the detection lead wire is determined based on the time parameters. The axial position of the leak point on the pipe is determined based on the location of the leak point on the detection wire, the pitch of the detection wire wound on the pipe, and the length of a single turn. The radial position of the leak point on the pipe is determined based on the location of the leak point on the detection guide and the length of a single turn of the detection guide.

8. A frequency-domain ground-penetrating radar tube leakage detection system, wherein the system applies the method described in any one of claims 1-7, characterized in that, The system includes: Frequency domain ground-penetrating radar is used to detect the entire pipeline section and obtain the raw electromagnetic wave signal. A data processing device is used to preprocess the original electromagnetic wave signal to obtain an echo signal; extract the time-frequency domain features of the echo signal and filter the time-frequency domain features; and use a leakage identification model to identify the filtered time-frequency domain features to obtain suspected leakage pipe sections. A microwave impedance measurement device is used to acquire the reflected signal of the suspected leaking pipe section. The microwave impedance measurement device includes a control unit and a detection wire. The detection wire is sleeved on a high-risk pipe section of the pipeline. The high-risk pipe section is a pipe section in the pipeline whose leakage risk value exceeds the risk threshold after the leakage risk value of the pipeline is assessed. The data processing device is also used to determine the axial and radial positions of the leakage point based on the reflected signal.

9. A frequency-domain ground-penetrating radar tube leakage detection system according to claim 8, characterized in that, The microwave impedance measurement device also includes a battery and a solar panel. Each high-risk pipe section is equipped with one of the microwave impedance measurement devices. The solar panel is used to charge the battery, and the battery is used to supply power to the control unit.

10. A frequency-domain ground-penetrating radar tube leakage detection system according to claim 8, characterized in that, Both the frequency-domain ground-penetrating radar and the microwave impedance measurement device are connected to the data processing device via wireless communication.

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