Large-burial-depth steel pipeline position detection method and device based on electromagnetic method

Abstract

The invention discloses a method and a device for detecting the position of a large-burial-depth steel pipeline based on an electromagnetic method, and aims to solve the problem of accurate detection of the large-burial-depth steel pipeline and improve the anti-interference capability. The device comprises a current source, a different-frequency magnetic field attenuation coefficient measuring device and a pipeline position detection magnetic field signal measuring device. The use method involves recording a magnetic field signal value, determining an attenuation coefficient, calculating the horizontal and vertical distances of the pipeline by using a Maxwell equation set, and improving the detection accuracy through a multi-frequency signal. According to the technical scheme, the steel pipeline with the burial depth exceeding 30 meters can be accurately detected, and the device is suitable for various working conditions including the areas where the pipeline passes through highways, ponds and the like, and people cannot enter the areas.

Description

Technical Field

[0001] The present invention relates to the technical field of deep buried steel pipeline detection, and in particular to a deep buried steel pipeline position detection method and device based on an electromagnetic method. Background Art

[0002] Electromagnetic detection technology is a method of detecting underground structures by using the principle of interaction between electromagnetic fields and underground media. It usually includes a transmitter and a receiver. The transmitter generates an electromagnetic field, while the receiver detects changes in the electromagnetic field caused by underground structures (such as pipelines). This method works well when detecting shallow structures, but when detecting deep layers, it is difficult to perform reliable detection because the attenuation coefficient of electromagnetic waves of different frequencies in the environment where the pipeline is located is unknown.

[0003] The seismic method is a method of detecting underground structures by generating seismic waves on the surface and detecting the propagation and reflection of these waves in underground structures. This method is more effective for detecting deep structures, but its accuracy is greatly affected by the uniformity of the soil medium, and it is not effective for detecting small-diameter pipes.

[0004] Existing electromagnetic methods, seismic or ground penetrating radar all require detection directly above the pipeline. When the historical data of the pipeline is lost or the pipeline is located on a highway or in water (rivers, lakes), it is impossible to perform detection directly above the pipeline. Summary of the invention

[0005] The present invention aims to provide a method and device for detecting the position of deep buried steel pipelines based on electromagnetic method, so as to solve the problems of low accuracy and difficult implementation of existing pipeline detection. The method is not limited by the diameter of the pipeline, and at the same time improves the anti-interference ability and expands the promotion and application scenarios.

[0006] To achieve the above object, the present invention provides the following technical solutions: a device for detecting the position of a deep buried steel pipeline based on electromagnetic method, comprising a current source, a device for measuring the attenuation coefficient of magnetic fields of different frequencies, and a device for measuring magnetic field signals for pipeline position detection;

[0007] The attenuation coefficient measuring device for magnetic fields of different frequencies comprises a non-metallic insulating plate, a long straight cable, a magnetic field sensor 1 and a magnetic field sensor 2 are fixedly connected to the top of the non-metallic insulating plate, the long straight cable is arranged horizontally, the midpoints of the magnetic field sensor 1, the magnetic field sensor 2 and the long straight cable are located on the same vertical line, and the long straight cable is connected to a current source through a wire;

[0008] The magnetic field signal measuring device for pipeline position detection includes a support column, the top end of the side wall of the support column is rotatably connected to a support plate through a bearing, the top end of the support plate is fixedly connected to three magnetic field sensors 3, 4 and 5 distributed in an equilateral triangle, the magnetic field sensor 3 is located at the vertex of the equilateral triangle, a downward weight is fixedly connected to the midpoint of the line connecting the magnetic field sensor 3, the magnetic field sensor 4 and the magnetic field sensor 5, and the vertex of the equilateral triangle is the rotation center of the support plate.

[0009] The method for using the above device comprises the following steps:

[0010] S1. Place the attenuation coefficient measuring device of magnetic field of different frequencies horizontally near the pipeline area to be measured, apply alternating current containing multiple frequencies to the long straight cable through an alternating current source, record the magnetic field signal values ​​of different frequencies collected by sensor 1 and sensor 2, and determine the attenuation coefficient of electromagnetic waves of different frequencies in the pipeline buried area through experimental calibration method;

[0011] S2. Place the magnetic field signal measuring device for pipeline position detection vertically in the pipeline area to be measured (with the weight pointing vertically downward), connect the alternating current source to the pipeline through a cable to form a loop, apply alternating current containing multiple frequencies to the pipeline, and record the magnetic field signal values ​​of different frequencies collected by sensor three, sensor four, and sensor five;

[0012] S3. Use Maxwell's equations to derive the calculation formulas for the horizontal and vertical distances of the pipeline from the measuring point;

[0013] S4. Substitute the experimentally determined attenuation coefficient of electromagnetic waves of different frequencies and the magnetic field value collected by the position detection and measurement device into the formula, and determine the horizontal and vertical distances of the pipeline by trial value method;

[0014] S5. During on-site detection, electromagnetic wave signals of multiple frequencies are used simultaneously. Data with similar results are determined through discrete analysis of the data, and the actual horizontal and vertical distances of the pipeline are obtained by taking the average value.

[0015] The principle and beneficial effects of this technical solution:

[0016] (1) Accurately calibrate the attenuation coefficient: The attenuation coefficient of electromagnetic waves of different frequencies in the pipeline buried area is accurately determined through experimental calibration method, which provides a scientific basis for the accurate calculation of the pipeline location. By designing a specific calibration device structure, the attenuation coefficient of electromagnetic waves of different frequencies in the pipeline location can be obtained in the field test, thus solving the problem that this key parameter cannot be obtained in the traditional method.

[0017] (2) Application of Maxwell's equations: Using Maxwell's equations, we derived the calculation formulas for the horizontal and vertical distances of the pipeline from the measuring point. Substituting the experimentally determined attenuation coefficient and the magnetic field value collected by the measuring device into the formula, we can accurately determine the horizontal and vertical distances of the pipeline through the trial value method, thus achieving accurate positioning of the pipeline.

[0018] (3) Application of multi-frequency signals: During on-site detection, the present invention uses electromagnetic wave signals of multiple frequencies at the same time, determines data with similar results through discrete analysis of the data, and obtains the actual horizontal and vertical distances of the pipeline by taking the average value. This effectively avoids the influence of electromagnetic interference from the surrounding environment on individual frequencies, and improves the ability of the detection device to resist electromagnetic interference from the surrounding environment.

[0019] (4) Innovative magnetic field signal measurement device: A magnetic field signal measurement device for pipeline position detection is designed. It can perform high-precision measurements at any position around the pipeline without having to be directly above the pipeline. It is suitable for various working conditions, including areas where the pipeline crosses highways, ponds, and other areas that are inaccessible to personnel.

[0020] (5) Deeply buried pipeline detection capability: This technical solution can accurately detect steel pipelines of any diameter buried at a depth of more than 30 meters, greatly expanding the application scope of electromagnetic detection technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of the attenuation coefficient measurement device of magnetic fields of different frequencies;

[0022] Figure 2 A schematic diagram of the structure of a magnetic field signal measuring device for pipeline position detection;

[0023] Figure 3 It is a schematic diagram of the sensor arrangement and the position relationship between each sensor and the pipeline;

[0024] Figure 4 The overall schematic diagram of the detection is shown in FIG.

[0025] In the figure: 1. current source; 2. non-metallic insulating flat plate; 3. long straight cable; 4. magnetic field sensor one; 5. magnetic field sensor two; 6. support column; 7. support plate; 8. magnetic field sensor three; 9. magnetic field sensor four; 10. magnetic field sensor five; 11. heavy hammer. DETAILED DESCRIPTION

[0026] The present invention is further described in detail below with reference to the accompanying drawings and embodiments:

[0027] The technical solution of the present invention is as follows:

[0028] A device for detecting the position of a deep buried steel pipeline based on an electromagnetic method, comprising a current source, a device for measuring the attenuation coefficient of magnetic fields of different frequencies, and a device for measuring magnetic field signals for detecting the position of the pipeline;

[0029] like Figure 1 As shown, the attenuation coefficient measuring device of magnetic fields of different frequencies includes a non-metallic insulating plate, a long straight cable, a magnetic field sensor 1 and a magnetic field sensor 2 are fixedly connected to the top of the non-metallic insulating plate, the long straight cable is horizontally arranged, the midpoints of the magnetic field sensor 1, the magnetic field sensor 2 and the long straight cable are located on the same vertical line, and the long straight cable is connected to the current source through a wire.

[0030] Use of the attenuation coefficient measuring device: Place the device horizontally near the pipeline area to be measured, apply alternating currents of multiple frequencies to the conductor through a current source, record the magnetic field signal values ​​of different frequencies collected by the sensor, and substitute the collected magnetic field signal values ​​of different frequencies into the following formula:

[0031]

[0032] The attenuation coefficient α of magnetic field signals with different frequencies is calculated.

[0033] like Figure 2 , 4 As shown, the magnetic field signal measuring device for pipeline position detection includes a support column, the top end of the side wall of the support column is rotatably connected to a support plate through a bearing, three magnetic field sensors 3, 4 and 5 distributed in an equilateral triangle are fixedly connected to the top end of the support plate, the magnetic field sensor 3 is located at the vertex of the equilateral triangle, a downward weight is fixedly connected to the midpoint of the line connecting the magnetic field sensor 3, the magnetic field sensor 4 and the magnetic field sensor 5, and the vertex of the equilateral triangle is the rotation center of the support plate to maintain the accuracy of the measurement.

[0034] Use of pipeline position detection device: insert the lower end of the support column into the soil. When implementing the detection, there is no need to place the detection device directly above the pipeline. It can be placed at any position of the pipeline. The horizontal and vertical distances of the pipeline from the measuring device can be calculated by measuring the magnetic field signal, which facilitates the rapid implementation of the detection and can be applied to working conditions where the pipeline crosses highways, ponds, etc. where people cannot approach.

[0035] Use a heavy hammer to ensure that the line connecting sensor 4 and sensor 5 is always in a horizontal state.

[0036] like Figure 3As shown, the three sensors are distributed in a triangle, the distance between sensor 4 and sensor 5 is Δx, and the distance between sensor 3 and the line connecting sensor 4 and sensor 5 is Δy2; the vertical distance of the pipeline distance detection device (pipeline burial depth h value) is calculated: the magnetic field signals of different frequencies collected by sensor 3 and sensor 4, the attenuation coefficients α and h corresponding to the magnetic fields of different frequencies are respectively substituted into the following formulas starting from 0 and increasing in steps of 0.01 to 100 (or the possible maximum burial depth of the pipeline + 20):

[0037]

[0038] A series of results corresponding to different h values ​​under different frequency conditions are obtained. The h corresponding to the minimum value in the screening results is the vertical distance of the pipeline from the detection device (the buried depth of the pipeline) obtained by the corresponding frequency detection; Calculation of the horizontal distance of the pipeline distance detection device (x value): Substitute the magnetic field signals of different frequencies collected by sensor four and sensor five, the attenuation coefficient α corresponding to the magnetic field of different frequencies, and x from 0 to 100 in steps of 0.01 (or the maximum possible horizontal distance of the pipeline distance measurement device + 20) into the following formulas:

[0039]

[0040] A series of results corresponding to different x values ​​under different frequency conditions are obtained, and the x corresponding to the minimum value in the screening results is the horizontal distance value of the pipeline from the detection device obtained by the corresponding frequency detection.

[0041] The horizontal distance and vertical distance of the pipeline distance measuring device are calculated by measuring the magnetic field signal. When implementing the detection, current signals of multiple frequencies are applied to the pipeline. The horizontal distance and vertical distance of the pipeline at different frequencies can be calculated based on the collected multiple magnetic field signals. Through the discreteness analysis of the horizontal and vertical distances, the data results with similar values ​​are retained, and the average value is taken as the final result, thereby realizing the ability to resist environmental electromagnetic interference.

[0042] The above is only an embodiment of the present invention, and the common knowledge such as the known specific technical solutions or characteristics in the solution is not described in detail here. For those skilled in the art, without departing from the technical solution of the present invention, several modifications and improvements can be made, which should also be regarded as the protection scope of the present invention, and these will not affect the effect of the implementation of the present invention and the practicality of the patent. The scope of protection required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to interpret the content of the claims.

Claims

1. A device for detecting the position of a deep buried steel pipeline based on electromagnetic method, characterized in that: It includes a current source, an attenuation coefficient measuring device for magnetic fields of different frequencies, and a magnetic field signal measuring device for pipeline position detection; The attenuation coefficient measuring device for magnetic fields of different frequencies comprises a non-metallic insulating plate, a long straight cable, a magnetic field sensor 1 and a magnetic field sensor 2 are fixedly connected to the top of the non-metallic insulating plate, the long straight cable is arranged horizontally, the midpoints of the magnetic field sensor 1, the magnetic field sensor 2 and the long straight cable are located on the same vertical line, and the long straight cable is connected to a current source through a wire; The magnetic field signal measuring device for pipeline position detection includes a support column, the top end of the side wall of the support column is rotatably connected to a support plate through a bearing, the top end of the support plate is fixedly connected to three magnetic field sensors 3, 4 and 5 distributed in an equilateral triangle, the magnetic field sensor 3 is located at the vertex of the equilateral triangle, a downward weight is fixedly connected to the midpoint of the line connecting the magnetic field sensor 3, the magnetic field sensor 4 and the magnetic field sensor 5, and the vertex of the equilateral triangle is the rotation center of the support plate.

2. A method for using the electromagnetic method-based deep buried steel pipeline position detection device according to claim 1, characterized in that: The method comprises the following steps: S1. Place the attenuation coefficient measuring device of magnetic field of different frequencies horizontally near the pipeline area to be measured, apply alternating current containing multiple frequencies to the long straight cable through an alternating current source, record the magnetic field signal values ​​of different frequencies collected by sensor 1 and sensor 2, and determine the attenuation coefficient of electromagnetic waves of different frequencies in the pipeline buried area through experimental calibration method; S2. Place the magnetic field signal measuring device for pipeline position detection vertically in the pipeline area to be measured (with the weight pointing vertically downward), connect the alternating current source to the pipeline through a cable to form a loop, apply alternating current containing multiple frequencies to the pipeline, and record the magnetic field signal values ​​of different frequencies collected by sensor three, sensor four, and sensor five; S3. Use Maxwell's equations to derive the calculation formulas for the horizontal and vertical distances of the pipeline from the measuring point; S4. Substitute the experimentally determined attenuation coefficient of electromagnetic waves of different frequencies and the magnetic field value collected by the position detection and measurement device into the formula, and determine the horizontal and vertical distances of the pipeline by trial value method; S5. During on-site detection, electromagnetic wave signals of multiple frequencies are used simultaneously. Data with similar results are determined through discrete analysis of the data, and the actual horizontal and vertical distances of the pipeline are obtained by taking the average value.

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