Pipeline radius detection method and detection device based on transient electromagnetic

Abstract

The application belongs to the technical field of underground pipeline detection, and specifically discloses a pipeline radius detection method and a detection device based on transient electromagnetic method, which comprises a pulse current generator, an excitation coil, a secondary induced magnetic field receiving module, a signal processing module, a signal transmission module and an upper computer module; the pulse current generator is used to generate transient current to establish a primary magnetic field, and a secondary induced magnetic field is established in the underground pipeline; the maximum value of the secondary magnetic field at different heights in the space is measured to obtain the pipeline burial depth; the magnetic field data is converted into magnetic field data under the standard burial depth condition, and the estimated value of the pipeline radius is obtained by comparing with the standard radius magnetic field curve. The application can measure the radius of the underground pipeline under the non-excavation condition, helps to improve the detection capability of the underground pipeline, and can accurately express the deep burial and radius of the underground pipeline.

Description

Technical Field

[0001] This invention belongs to the field of underground pipeline detection technology, specifically relating to a pipeline radius detection method and detection device based on transient electromagnetics. Background Technology

[0002] Underground pipelines play a vital role in the daily operation of modern cities. They are irreplaceable in various applications, including domestic water supply, wastewater discharge, natural gas transportation, electricity transmission, and fiber optic information channels. However, with the continuous advancement of urban construction, underground pipeline networks are becoming increasingly complex. Coupled with inadequate data preservation and a lack of overall planning and coordination among construction departments, many undiscovered underground pipelines remain in cities. These pipelines pose significant safety hazards to urban construction. Therefore, identifying and addressing these missing pipeline information has become a crucial aspect of urban development and construction.

[0003] Many technologies exist for pipeline detection. Among these, the difference in physical parameters between the underground pipeline and the buried medium is commonly used. Examples include high-precision geomagnetic detection and ground-penetrating radar (GPR). High-precision geomagnetic detection requires no excitation source and utilizes the distortion of the geomagnetic field caused by underground ferromagnetic pipes to determine the pipeline's location and depth. However, it is easily affected by various factors and struggles to accurately describe the radius. GPR receives echo signals reflected from underground pipelines to image them, but it is also susceptible to interference from groundwater and underground non-metallic materials, resulting in inaccurate radius descriptions. Therefore, a method is needed to provide a simple and rapid estimate of pipeline depth and radius. Summary of the Invention

[0004] In order to overcome the shortcomings of the prior art, the purpose of this invention is to provide a pipeline radius detection method and detection device based on transient electromagnetics, so as to solve the problem that the prior art cannot accurately describe the pipeline depth and radius of underground pipelines.

[0005] To achieve the above objectives, the present invention employs the following technical solution:

[0006] In a first aspect, the present invention provides a pipe radius detection method based on transient electromagnetics, comprising:

[0007] S1: Place the detection device in the calibration environment and collect the secondary induced magnetic field;

[0008] S2: The detection device is placed directly above the pipe; a pulsed current is applied to the detection device, and the maximum value of the secondary magnetic field of the pipe after the excitation disappears is recorded, thus obtaining the maximum value B of the secondary magnetic field. m By changing the pipes to different radii r, the maximum value of the secondary magnetic field is recorded, and the standard rB under the calibration environment is obtained. m curve;

[0009] S3: Place the detection device near the pipe to be tested, perform detection, find the location of the maximum magnetic field response signal on the horizontal measuring line, and record the maximum magnetic field response signal.

[0010] S4: Fix the detection device at the point where the magnetic field response signal is maximum, and record the maximum value of the secondary magnetic field M1 at this time; move the magnetic field measurement module in the detection device up a distance L along the vertical measuring line, and record the maximum value of the secondary magnetic field M2 after the movement.

[0011] S5: Calculate the burial depth d of underground pipelines;

[0012] S6: Convert M1 under the burial depth d case into magnetic field data under standard burial depth, obtain the relationship between the maximum value of the secondary magnetic field and the burial depth under the same radius and the fitting curve, and obtain the maximum value of the secondary magnetic field M0 under standard burial depth.

[0013] S7: Compare M0 with the standard rB under calibration conditions m By comparing the curves, we can obtain an estimated value for the radius of the buried pipeline.

[0014] Furthermore, the detection device includes an excitation coil and a magnetic field measurement module located at the center of the coil; after the detection device is placed in the calibration environment, the excitation coil generates a pulse current, and the magnetic field measurement module collects the secondary induced magnetic field.

[0015] Furthermore, in step 2, the distance between the geometric center of the pipeline and the horizontal plane where the detection device is located is 1m at the standard burial depth.

[0016] Furthermore, in step 2, the pulse current is applied and the maximum value of the secondary magnetic field of the pipeline after the excitation disappears is recorded as follows: a pulse current is applied to the excitation coil, and the magnetic field measurement module records the magnetic field response signal of the pipeline after the excitation disappears.

[0017] Furthermore, the location of the maximum value of the magnetic field response signal is the location of the measuring point where the amplitude of the secondary induced magnetic field is the largest.

[0018] Furthermore, the calculation method for the burial depth d of the underground pipeline is as follows:

[0019] d: Burial depth of underground pipelines, in meters;

[0020] M1: The maximum value of the secondary magnetic field before movement, in μT;

[0021] M2: The maximum value of the secondary magnetic field after movement, in μT;

[0022] L: Distance traveled.

[0023] Furthermore, the maximum value M0 of the secondary magnetic field at the standard burial depth is inversely proportional to the fourth power of the burial depth:

[0024] M0 = M1·d 4

[0025] M0: The maximum value of the secondary magnetic field at standard burial depth, in μT.

[0026] Secondly, the present invention provides a detection device based on transient electromagnetic fields, comprising:

[0027] The system includes a pulse current generator, an excitation coil, a secondary induced magnetic field receiving module, a signal processing module, a signal transmission module, and a host computer module. The pulse current generator is connected to the excitation coil. The pulse current generator is used to provide pulse current to the excitation coil. The secondary induced magnetic field receiving module is used to collect the secondary induced magnetic field and output the signal to the signal processing module. The signal processing module is connected to the signal transmission module, and the signal transmission module is connected to the host computer module.

[0028] When the transient electromagnetic detection device performs detection, it includes the following steps:

[0029] S1: Place the detection device in the calibration environment and collect the secondary induced magnetic field;

[0030] S2: The detection device is placed directly above the pipe; a pulse current generator supplies a pulse current to the excitation coil, and the maximum value of the secondary magnetic field after the excitation disappears is recorded, thus obtaining the maximum value B of the secondary magnetic field. m By changing the pipes to different radii r, the maximum value of the secondary magnetic field is recorded, and the standard rB under the calibration environment is obtained. m curve;

[0031] S3: Place the detection device near the pipe to be tested, perform detection, find the location of the maximum magnetic field response signal on the horizontal measuring line, and record the maximum magnetic field response signal.

[0032] S4: Fix the detection device at the point where the magnetic field response signal is maximum, and record the maximum value of the secondary magnetic field M1 at this time; move the magnetic field measurement module in the detection device up a distance L along the vertical measuring line, and record the maximum value of the secondary magnetic field M2 after the movement.

[0033] S5: Calculate the burial depth d of underground pipelines;

[0034] S6: Convert M1 under the burial depth d case into magnetic field data under standard burial depth, obtain the relationship between the maximum value of the secondary magnetic field and the burial depth under the same radius and the fitting curve, and obtain the maximum value of the secondary magnetic field M0 under standard burial depth.

[0035] S7: Compare M0 with the standard rB under calibration conditions m By comparing the curves, we can obtain an estimated value for the radius of the buried pipeline.

[0036] Furthermore, the excitation coil is a horizontally placed multi-turn rectangular coil.

[0037] Furthermore, the secondary induction magnetic field receiving module includes a magnetic field measurement module and an ADC module, with the magnetic field measurement module connected to the ADC module; the ADC module is connected to the signal processing module.

[0038] The present invention has at least the following beneficial effects:

[0039] This invention utilizes a pulse current generator to produce transient current and establish a primary magnetic field, and then establishes a secondary induced magnetic field within the underground pipeline. By measuring the maximum value of the secondary magnetic field at different heights in space, the pipeline burial depth is obtained. By converting the magnetic field data to magnetic field data under standard burial depth conditions and comparing it with a standard radius-magnetic field curve, an estimated value of the pipeline radius is obtained. This invention enables the measurement of the radius of underground pipelines without excavation, which helps improve the detection capability of underground pipelines and allows for accurate description of the burial depth and radius of underground pipelines. Attached Figure Description

[0040] The accompanying drawings, which form part of this specification, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0041] Figure 1 This is a schematic diagram of the process of the present invention;

[0042] Figure 2 This is a schematic diagram of the detection device.

[0043] Figure 3 This is a schematic diagram showing the placement of the excitation coil and magnetic field sensor of the present invention;

[0044] Figure 4 The relationship between the maximum value of the secondary magnetic field and the burial depth under the same radius, and the fitted curve;

[0045] Figure 5 The relationship between the maximum value of the secondary magnetic field and the pipe radius after conversion to the standard burial depth condition, and the fitted curve.

[0046] Reference numerals: 1. Pipe; 2. Excitation coil; 3. Magnetic field sensor before movement; 4. Magnetic field sensor after movement. Detailed Implementation

[0047] The present invention will now be described in detail with reference to the accompanying drawings and embodiments. It should be noted that, unless otherwise specified, the embodiments and features described herein can be combined with each other.

[0048] The following detailed description is exemplary and intended to provide further detailed explanation of the invention. Unless otherwise specified, all technical terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art. The terminology used in this invention is for describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention.

[0049] Example 1

[0050] like Figure 1 As shown, a pipe radius detection method based on transient electromagnetics includes:

[0051] S1: Place the detection device in the calibration environment, the excitation coil 2 generates a pulse current, and the magnetic field measurement module collects the secondary induced magnetic field; the calibration environment consists of only a pipe 1 with a known radius r and the detection device within a certain spatial range. The detection device includes a rectangular excitation coil 2 and a magnetic field measurement module located at the center of the coil. The excitation coil 2 is a 20-turn copper coil with a rectangular side length of 1m. The magnetic field measurement accuracy of the magnetic field measurement module is on the order of nanotesla.

[0052] According to the principle of transient electromagnetic method, the calibration environment should not contain any metal objects other than the pipe. The field range of the calibration environment can be considered as a sphere with a radius of 10m, centered at the midpoint of the line connecting the center of the pipe and the center of the detection device. Non-metallic substances do not affect the detection.

[0053] S2: As Figure 3 As shown, the detection device is placed directly above pipe 1, such that the distance between the geometric center of the cylindrical pipe 1 and the horizontal plane where the detection device is located is 1m at the standard burial depth. A pulse current is passed through the excitation coil 2, and the magnetic field measurement module records the magnetic field response signal of pipe 1 after the excitation disappears, obtaining the maximum value B of the response signal. m By replacing the pipes with different radii r, and recording the maximum value of the response signal, the standard rB under the calibration environment can be obtained. m curve.

[0054] The pulse current is generated using a pulse current generator, with a pulse current amplitude of 10–30 A, a pulse current width of 40–50 μs, and a fall time of 20–30 A / μs.

[0055] S3: Place the detection device near the pipe to be tested 1, move the excitation coil 2 and the magnetic field sensor at equal intervals along the horizontal measuring line, perform detection at each measuring point, find the position of the maximum magnetic field response signal on the horizontal measuring line, and record the maximum value.

[0056] The material of the calibration environment pipeline should be consistent with that of the pipeline under test, and the pipeline length should be greater than or equal to 10m. If actual conditions cannot meet the calibration requirements, the standard rB... m The curve can be obtained from finite element simulation experiments.

[0057] The measuring line contains several measuring points, with a distance of less than or equal to 10cm between them. The location of the maximum response signal is the location of the measuring point with the largest amplitude of the secondary induced magnetic field.

[0058] S4: Fix the detection device at the point where the magnetic field response signal is at its maximum, and record the maximum value of the secondary magnetic field M1 at this time; move the magnetic field measurement module in the detection device up a distance L along the vertical measuring line, and record the maximum value of the secondary magnetic field M2 after the movement.

[0059] The excitation coil 2 is moved upward by L while the magnetic field sensor moves vertically upward. A larger upward movement can ensure the accuracy of the burial depth calculation formula, but it should also ensure that the magnetic field sensor can collect the exponentially decreasing magnetic field strength waveform of the secondary magnetic field.

[0060] S5: Calculate the burial depth d of underground pipelines using the following equation:

[0061]

[0062] d: Burial depth of underground pipelines, in meters;

[0063] M1: The maximum value of the secondary magnetic field measured by the magnetic field sensor 3 before movement, in μT;

[0064] M2: The maximum value of the secondary magnetic field measured by the magnetic field sensor 4 after the movement, in μT;

[0065] L: Distance traveled.

[0066] S6: Convert M1 at burial depth d into magnetic field data at standard burial depth, as shown below. Figure 4 The relationship between the maximum value of the secondary magnetic field and the burial depth under the same radius, as well as the fitted curve, are shown. The maximum value M0 of the secondary magnetic field at the standard burial depth is obtained. The result is described as follows: the maximum value of the magnetic field under the same radius is inversely proportional to the fourth power of the burial depth.

[0067] M0 = M1·d 4

[0068] M0: Maximum value of the secondary magnetic field at standard burial depth, in μT;

[0069] S7: Compare M0 with the standard rB under calibration conditions m Curve comparison, such as Figure 5 As shown, the estimated radius of the buried pipeline is obtained.

[0070] according to Figure 4As shown in the figure, the relationship between the maximum value of the secondary magnetic field and the burial depth under the same radius, as well as the fitting curve, shows that the maximum value of the secondary magnetic field is inversely proportional to the fourth power of the burial depth. The fitting relationship is good under the three burial depths. The burial depth of the pipeline can be calculated based on two measurement points at different heights.

[0071] like Figure 5 As shown, after converting pipelines of different burial depths to the standard burial depth, the radius has a consistent relationship with the maximum value of the secondary magnetic field. The estimated value of the pipeline radius can be obtained from the curve under the standard burial depth.

[0072] In one embodiment, the measured pipe radius was 15cm and the burial depth was 1m, while the estimated pipe radius using the detection device was 15.8cm and the burial depth was 1.12m. It can be seen that the present invention can obtain the pipe radius and burial depth information simply and relatively accurately. Based on the pipe radius detection method under transient electromagnetic excitation, a transient current is generated by a pulse current generator to establish a primary magnetic field, and a secondary induced magnetic field is established in the underground pipeline. The pipe burial depth is obtained by measuring the maximum value of the secondary magnetic field at different heights in space. By converting the magnetic field data to the magnetic field data under the standard burial depth condition, the estimated value of the pipe radius is obtained by comparing it with the standard radius magnetic field curve, which has a good effect.

[0073] Example 2

[0074] like Figure 2 As shown, a detection device based on transient electromagnetics includes:

[0075] The system includes a pulse current generator, an excitation coil 2, a secondary induced magnetic field receiving module, a signal processing module, a signal transmission module, and a host computer module. The pulse current generator is connected to the excitation coil 2. The pulse current generator is used to provide pulse current to the excitation coil 2. The secondary induced magnetic field receiving module is used to collect the secondary induced magnetic field and output the signal to the signal processing module. The signal processing module is connected to the signal transmission module, and the signal transmission module is connected to the host computer module.

[0076] When a detection device based on transient electromagnetic fields performs detection, the following steps are included:

[0077] S1: Place the detection device in the calibration environment and collect the secondary induced magnetic field;

[0078] S2: The detection device is placed directly above pipe 1; the pulse current generator supplies pulse current to the excitation coil 2, and records the maximum value of the secondary magnetic field of pipe 1 after the excitation disappears, obtaining the maximum value B of the secondary magnetic field. m By changing the pipes to different radii r, the maximum value of the secondary magnetic field is recorded, and the standard rB under the calibration environment is obtained. m curve;

[0079] S3: Place the detection device near the pipe to be tested, perform detection, find the location of the maximum magnetic field response signal on the horizontal measuring line, and record the maximum magnetic field response signal.

[0080] S4: Fix the detection device at the point where the magnetic field response signal is maximum, and record the maximum value of the secondary magnetic field M1 at this time; move the magnetic field measurement module in the detection device up a distance L along the vertical measuring line, and record the maximum value of the secondary magnetic field M2 after the movement.

[0081] S5: Calculate the burial depth d of underground pipelines;

[0082] S6: Convert M1 under the burial depth d case into magnetic field data under standard burial depth, obtain the relationship between the maximum value of the secondary magnetic field and the burial depth under the same radius and the fitting curve, and obtain the maximum value of the secondary magnetic field M0 under standard burial depth.

[0083] S7: Compare M0 with the standard rB under calibration conditions m By comparing the curves, we can obtain an estimated value for the radius of the buried pipeline.

[0084] The pulse current generator can provide pulse current that meets the requirements for amplitude, current width, and fall time;

[0085] The excitation coil is a transient magnetic field excitation coil, which is a horizontally placed multi-turn rectangular coil used to establish a spatial transient magnetic field.

[0086] The secondary induced magnetic field receiving module comprises a magnetic field measurement module and an ADC module. The magnetic field measurement module is connected to the ADC module, which in turn is connected to the signal processing module. The core component of the secondary induced magnetic field receiving module is the magnetic field measurement module, whose output current is related to its single-axis magnetic field strength. The magnetic field measurement module can be either single-axis or triaxial, with the latter offering higher detection accuracy. If it is a single-axis module, the vertical magnetic field component should be measured; if it is a triaxial module, the composite magnetic field amplitude should be calculated.

[0087] The ADC module must be at least a 24-bit ADC module.

[0088] The signal processing module, based on the STM32F407 microcontroller, collects the digital signal converted by the ADC module and inputs it into the microcontroller, performs necessary linear conversion and moving average filtering, and obtains the numerical sequence of the induced magnetic field.

[0089] The signal transmission module is a USB-to-serial converter chip responsible for data transmission between the microcontroller and the host computer. It converts the microcontroller's serial port signals into USB signals at a transmission speed of 4 Mbps.

[0090] The host computer module is built using LabVIEW. It acquires data from the microcontroller, plots and stores multiple magnetic field curves during the detection process, finds the maximum value of the required magnetic field, calculates the pipe burial depth according to the formula, and further calculates the pipe radius based on the burial depth.

[0091] As is known from common technical knowledge, this invention can be implemented through other embodiments that do not depart from its spirit or essential characteristics. Therefore, the disclosed embodiments described above are merely illustrative in all respects and are not the only ones. All modifications within the scope of this invention or equivalent to the scope of this invention are included in this invention.

[0092] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A method for detecting the radius of a pipe based on transient electromagnetics, characterized in that, include: S1: Place the detection device in the calibration environment and collect the secondary induced magnetic field; S2: The detection device is placed directly above the pipe (1); The detection device is supplied with a pulse current, and the maximum value of the secondary magnetic field of the pipe (1) after the excitation disappears is recorded, thus obtaining the maximum value of the secondary magnetic field B. m By changing the pipes to different radii r, the maximum value of the secondary magnetic field is recorded, and the standard rB under the calibration environment is obtained. m curve; S3: Place the detection device near the pipe to be tested, perform detection, find the location of the maximum magnetic field response signal on the horizontal measuring line, and record the maximum magnetic field response signal. S4: Fix the detection device at the point where the magnetic field response signal is at its maximum, and record the maximum value of the secondary magnetic field M1 at this time; move the magnetic field measurement module in the detection device up a distance L along the vertical measuring line, and record the maximum value of the secondary magnetic field M2 after the move. S5: Calculate the burial depth d of the underground pipeline; the calculation method for the burial depth d of the underground pipeline is as follows: ; in, d: Burial depth of underground pipeline, in meters; M1: Maximum value of the secondary magnetic field before relocation, in μT; M2: Maximum value of the secondary magnetic field after relocation, in μT; L: Relocation distance; S6: Convert M1 at burial depth d to magnetic field data at standard burial depth, obtain the relationship between the maximum value of the secondary magnetic field and burial depth for the same radius, and the fitted curve, and obtain the maximum value of the secondary magnetic field at standard burial depth. ; S7: Compare M0 with the standard rB under calibration conditions m By comparing the curves, we can obtain an estimated value for the radius of the buried pipeline.

2. The pipe radius detection method based on transient electromagnetics according to claim 1, characterized in that, The detection device includes an excitation coil (2) and a magnetic field measurement module located at the center of the coil; after the detection device is placed in the calibration environment, the excitation coil (2) generates a pulse current, and the magnetic field measurement module collects the secondary induced magnetic field.

3. The pipe radius detection method based on transient electromagnetics according to claim 1, characterized in that, The distance between the geometric center of the pipeline (1) in step 2 and the horizontal plane where the detection device is located is 1m at the standard burial depth.

4. The pipe radius detection method based on transient electromagnetics according to claim 2, characterized in that, In step 2, a pulse current is passed through the pipe (1) and the maximum value of the secondary magnetic field after the excitation disappears is recorded. Specifically, a pulse current is passed through the excitation coil (2) and the magnetic field measurement module records the magnetic field response signal of the pipe (1) after the excitation disappears.

5. The pipe radius detection method based on transient electromagnetics according to claim 1, characterized in that, The location of the maximum value of the magnetic field response signal is the location of the measuring point where the amplitude of the secondary induced magnetic field is the largest.

6. The pipe radius detection method based on transient electromagnetics according to claim 1, characterized in that, The maximum value of the secondary magnetic field at the standard burial depth It is inversely proportional to the fourth power of the burial depth: ； : Maximum value of the secondary magnetic field at standard burial depth, in μT.

7. A detection device based on transient electromagnetics, characterized in that, include: Pulse current generator, excitation coil (2), secondary induction magnetic field receiving module, signal processing module, signal transmission module and host computer module; The pulse current generator is connected to the excitation coil (2); the pulse current generator is used to provide pulse current to the excitation coil (2); the secondary induced magnetic field receiving module is used to collect the secondary induced magnetic field and output the signal to the signal processing module; the signal processing module is connected to the signal transmission module; and the signal transmission module is connected to the host computer module. When the transient electromagnetic detection device performs detection, it includes the following steps: S1: Place the detection device in the calibration environment and collect the secondary induced magnetic field; S2: The detection device is placed directly above the pipe (1); the pulse current generator supplies pulse current to the excitation coil (2), and records the maximum value of the secondary magnetic field of the pipe (1) after the excitation disappears, thus obtaining the maximum value B of the secondary magnetic field. m By changing the pipes to different radii r, the maximum value of the secondary magnetic field is recorded, and the standard rB under the calibration environment is obtained. m curve; S3: Place the detection device near the pipe to be tested, perform detection, find the location of the maximum magnetic field response signal on the horizontal measuring line, and record the maximum magnetic field response signal. S4: Fix the detection device at the point where the magnetic field response signal is at its maximum, and record the maximum value of the secondary magnetic field M1 at this time; move the magnetic field measurement module in the detection device up a distance L along the vertical measuring line, and record the maximum value of the secondary magnetic field M2 after the move. S5: Calculate the burial depth d of the underground pipeline; the calculation method for the burial depth d of the underground pipeline is as follows: Where, d: burial depth of underground pipeline, in meters; M1: maximum value of the secondary magnetic field before movement, in μT; M2: maximum value of the secondary magnetic field after movement, in μT; L: movement distance; S6: Convert M1 at burial depth d to magnetic field data at standard burial depth, obtain the relationship between the maximum value of the secondary magnetic field and burial depth for the same radius, and the fitted curve, and obtain the maximum value of the secondary magnetic field at standard burial depth. ; S7: Compare M0 with the standard rB under calibration conditions m By comparing the curves, we can obtain an estimated value for the radius of the buried pipeline.

8. A detection device based on transient electromagnetics according to claim 7, characterized in that, The excitation coil (2) is a horizontally placed multi-turn rectangular coil.

9. A detection device based on transient electromagnetics according to claim 7, characterized in that, The secondary induction magnetic field receiving module includes a magnetic field measurement module and an ADC module. The magnetic field measurement module is connected to the ADC module, and the ADC module is connected to the signal processing module.

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