A multi-frequency electromagnetic fusion non-excavation method and device for identifying the materials of underground facilities

Abstract

The present invention belongs to the technical field of underground pipeline detection, and discloses a multi-frequency electromagnetic fusion non-excavation type underground facility material identification method and device. It includes S1: On the area where the underground facility material is not identified, set up transmitting and receiving coils, adjust the distance between the receiving coil and the transmitting coil, and respectively collect the component By<subgt;Pn< / subgt; of the y-axis of the alternating magnetic field generated during the movement of the receiving coil, as well as the original databases A1 and A2 of the alternating magnetic field collected at different positions between the lowest point and the highest point of the receiving coil; S2: On the area where the underground facility material is identified, obtain the component By<subgt;measured P1< / subgt; of the y-axis of the alternating magnetic field of the receiving coil; S3: Move the receiving coil to obtain the difference between the y-axis component and the y-axis component of the alternating magnetic field in the non-detection area and the curve of the alternating magnetic field changing with frequency; S4: Compare the collected alternating magnetic field data with the original database A1 of the alternating magnetic field, establish a data curve, and judge the material type of the underground facility according to the curve and the magnitudes of the magnetic permeability and conductivity.

Description

Technical Field

[0001] The present invention belongs to the technical field of underground pipeline detection, and particularly relates to a method and device for identifying the materials of underground facilities by multi-frequency electromagnetic fusion and non-excavation. Background Art

[0002] Urban underground facilities play a huge role in ensuring the country's economic development and the stability of residents' lives. They are important basic facilities for urban construction. However, due to factors such as poor management or inadequate consideration during the initial construction period, it is difficult to identify the location, structural material, and use of underground facilities. Heating pipelines, rainwater pipelines, and power pipelines are intertwined, and accidents of construction damage to underground facilities occur frequently. Therefore, it is necessary to conduct research on the location and related material identification of underground facilities, so as to determine the actual use of the facilities and provide necessary data support for subsequent urban planning and construction management. Among them, the identification of the materials of underground facilities is relatively difficult and is also a difficult problem in the field of underground facility detection.

[0003] In related technologies, the geomagnetic field perturbation method and the ground penetrating radar high-frequency electromagnetic wave reflection method are the main methods for identifying the materials of underground facilities: for example, by using the phenomenon that ferromagnetic metal facilities can cause magnetic anomalies in the geomagnetic environment, the positioning of underground ferromagnetic facilities can be realized. However, it cannot identify non-magnetic aluminum and copper materials; for another example, the ground penetrating radar uses the reflection characteristics of high-frequency electromagnetic waves to detect the location and size of underground facilities, and judges the materials of underground facilities according to the amplitude strength of the reflected wave signals. However, it has certain requirements for the water content of the soil and has a great dependence on the experience and knowledge of the detection personnel. The estimation of materials also varies from person to person, and the identification accuracy is low. And in the process of identification, for underground facilities that cannot be identified magnetically, it is necessary to excavate the pipelines that cannot be identified one by one to determine the types of underground pipelines, which is time-consuming, laborious, and inefficient. Summary of the Invention

[0004] In order to solve the problems existing in the prior art, the present invention provides a method and device for identifying the materials of underground facilities by multi-frequency electromagnetic fusion and non-excavation, with high efficiency, meeting the operation requirements of easy identification of the materials of underground facilities and not requiring excavation to determine the material types.

[0005] In order to achieve the above object, the present invention provides the following technical solutions:

[0006] A method for identifying the materials of underground facilities by multi-frequency electromagnetic fusion and non-excavation includes the following steps

[0007] S1: On the non-identifying area of the underground facility material, place the transmitting coil at the lowest position P1 on the ground, and concentrically set the receiving coil with the transmitting coil. Take the horizontal direction as the x-axis direction and the vertical direction as the y-axis direction. Establish a two-dimensional coordinate system with the center of the receiving coil and the transmitting coil as the center of the circle, and record the y-axis component By of the alternating magnetic field generated by the transmitting coil. P1 Move the receiving coil along the positive y-axis to different positions, and respectively record the y-axis component By of the alternating magnetic field generated by the transmitting coil at different positions. Pn Here, n represents different positions where the transmitting coil is located when moving along the positive y-axis, and n is 2, 3, 4... respectively establish the original databases A1 and A2 of the alternating magnetic field collected at different positions between the lowest point and the highest point of the receiving coil under the conditions that the buried depth, permeability, and conductivity of the underground facility are fixed, and the transmitting frequency of the transmitting coil and the permeability and conductivity of the underground facility change respectively.

[0008] S2: On the identifying area of the underground facility material, place the transmitting coil at the lowest position P1 on the ground, and move the transmitting coil within the identifying area. Record the difference between the y-axis component of the alternating magnetic field obtained by the receiving coil and the y-axis component of the alternating magnetic field in the non-detecting area. When the absolute value of the difference is the largest, record the horizontal position where the transmitting coil is located and the y-axis component By of the alternating magnetic field obtained by the receiving coil. 测P1 ;

[0009] S3: Move the receiving coil from low to high, record the difference between the y-axis component and the y-axis component of the alternating magnetic field in the non-detecting area during the process of the receiving coil moving from low to high, and perform normalization processing to obtain the normalized data. Establish a curve of the alternating magnetic field changing with frequency according to the normalized data.

[0010] S4: Compare the collected alternating magnetic field data with the original database A1 of the alternating magnetic field, select an alternating magnetic field curve with the highest degree of coincidence in curve trend, determine the relative permeability and conductivity of the underground facility, and determine the property of the underground facility material according to the magnitudes of the permeability and conductivity.

[0011] Further, if the relative permeability of the underground facility is greater than 1.05, it is a ferromagnetic material. If the relative permeability of the underground facility is between 0.95 - 1.05, then compare the collected alternating magnetic field data with the original database A2 of the alternating magnetic field, select an alternating magnetic field curve with the same degree of coincidence in curve trend, and determine the conductivity of the underground facility; if the conductivity σ of the underground facility > 10 5 S / m, it is a non-ferromagnetic material. If the conductivity σ of the underground facility ≤ 10 5 S / m, it is a non-metallic material.

[0012] Further, when the receiving coil moves between the lowest point and the highest point, it moves at equal intervals.

[0013] Furthermore, the relationship between the radius r1 of the transmitting coil and the radius r2 of the receiving coil is: r1 > 0.5 m and r2 < 0.2 m.

[0014] Furthermore, the normalization process is a process of dividing the initial data by the maximum value in the initial dataset.

[0015] Furthermore, when determining the material of the underground facility, the burial depth of the underground facility is the same as the calculation depth.

[0016] Furthermore, the burial depth d of the underground facility satisfies the following relationship:

[0017]

[0018] In the formula, d1 is the straight-line distance between the receiving coil and the transmitting coil when the receiving coil moves along the positive y-axis direction.

[0019] Furthermore, when the receiving coil is at the lowest point on the ground, the receiving coil is concentrically arranged inside the transmitting coil, and the receiving coil and the transmitting coil are in the same plane.

[0020] Furthermore, after determining the type of material of the underground facility, the specific material type is determined by querying the material manual of the corresponding material type.

[0021] A multi-frequency electromagnetic fusion non-excavation underground facility material identification system includes:

[0022] Non-identification area data acquisition module: used to place the transmitting coil at the lowest position P1 on the ground in the non-identification area of the underground facility material, concentrically set the receiving coil with the transmitting coil, establish a two-dimensional coordinate system with the horizontal direction as the x-axis direction and the vertical direction as the y-axis direction, and record the y-axis component By of the alternating magnetic field generated by the transmitting coil. P1 Move the receiving coil along the positive y-axis direction to different positions, and respectively record the y-axis component By of the alternating magnetic field generated by the transmitting coil at different positions. Pn where n is the different positions where the transmitting coil is located when moving along the positive y-axis direction, n is 2, 3, 4..., respectively establish the original databases A1 and A2 of the alternating magnetic field collected at different positions between the lowest point and the highest point of the receiving coil under the conditions that the burial depth of the underground facility and the magnetic permeability and conductivity are fixed, and the transmitting frequency of the transmitting coil and the magnetic permeability and conductivity of the underground facility change respectively.

[0023] Recognition area data acquisition module: It is used to place the transmitting coil at the lowest position P1 on the ground in the underground facility material recognition area, move the transmitting coil within the recognition area, record the difference between the y-axis component of the alternating magnetic field obtained by the receiving coil and the y-axis component of the alternating magnetic field in the non-detection area, and when the absolute value of the difference is the largest, record the horizontal position where the transmitting coil is located and the y-axis component By of the alternating magnetic field obtained by the receiving coil 测P1 ;

[0024] Data processing module: It is used to move the receiving coil from low to high, record the difference between the y-axis component during the process of the receiving coil moving from low to high and the y-axis component of the alternating magnetic field in the non-detection area, perform normalization processing to obtain the normalized data, and establish a curve of the alternating magnetic field varying with frequency based on the normalized data;

[0025] Judgment module: It is used to compare the collected alternating magnetic field data with the original alternating magnetic field database A1, select an alternating magnetic field curve with the highest degree of coincidence in curve trend, determine the relative magnetic permeability and conductivity of the underground facility, and determine the attribute of the underground facility material according to the magnitudes of the magnetic permeability and conductivity.

[0026] Compared with the prior art, the advantages of the present invention are as follows:

[0027] A multi-frequency electromagnetic fusion non-excavation method for identifying underground facility materials of the present invention sets a receiving coil and a transmitting coil in the material recognition area and the non-material recognition area on the ground respectively, adjusts the straight-line distance between the receiving coil and the transmitting coil, obtains the y-axis component of the alternating magnetic field of the transmitting coil in the material recognition area and the non-material recognition area, and the transmitting coil emits a multi-frequency electromagnetic fusion signal, and takes the position where the difference in the response amplitude of the alternating electromagnetic signal is the largest as the position for identifying the underground facility material; by detecting the buried depth of the underground facility and the response difference of the magnetic field amplitude signal with the transmitting frequency when the magnetic permeability and conductivity are different, comparing the difference between the original alternating magnetic field standard database and the test alternating magnetic field signal, so as to identify the underground facility material, and solves the problems of difficult identification of underground facility materials, low efficiency and the need for excavation detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The specification drawings forming a part of the present invention are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention.

[0029] In the drawings:

[0030] Figure 1 is a schematic flow chart of a multi-frequency electromagnetic fusion non-excavation method for identifying underground facility materials of the present invention;

[0031] Figure 2Schematic diagram of the distribution of the receiving coil and the transmitting coil in the material identification area of a multi - frequency electromagnetic fusion non - excavation underground facility material identification method of the present invention;

[0032] Figure 3 Relationship diagram between the amplitude of the alternating magnetic field and the buried depth of the underground facility in a multi - frequency electromagnetic fusion non - excavation underground facility material identification method of the present invention;

[0033] Figure 4 Schematic diagram of the variation law of the magnetic field amplitude with the transmitting frequency and the response curve of part of the original database A1 when the permeability is unknown in a preferred embodiment of a multi - frequency electromagnetic fusion non - excavation underground facility material identification method of the present invention;

[0034] Figure 5 Schematic diagram of the variation law of the magnetic field amplitude with the transmitting frequency and the response curve of part of the original database A2 when the conductivity is unknown in a preferred embodiment of a multi - frequency electromagnetic fusion non - excavation underground facility material identification method of the present invention;

[0035] Wherein: receiving coil 1, transmitting coil 2, underground facility 3. Detailed implementation manner

[0036] The present invention will be described in detail below with reference to the drawings and in conjunction with embodiments. It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other.

[0037] The following detailed descriptions are all exemplary descriptions, aiming to provide further detailed descriptions of the present invention. Unless otherwise specified, all technical terms used in the present invention have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention belongs. The terms used in the present invention are only for describing specific embodiments, and are not intended to limit the exemplary embodiments according to the present invention.

[0038] Embodiment 1

[0039] A multi - frequency electromagnetic fusion non - excavation underground facility material identification method, as Figure 1 shown, includes the following steps,

[0040] S1: On the area where the underground facility material is not identified, place the transmitting coil at the lowest position P1 on the ground, and concentrically set the receiving coil with the transmitting coil. Establish a two - dimensional coordinate system with the horizontal direction as the x - axis direction and the vertical direction as the y - axis direction, and record the y - axis component By of the alternating magnetic field generated by the transmitting coil P1 , move the receiving coil along the positive y - axis to different positions, and respectively record the y - axis components By of the alternating magnetic field generated by the transmitting coil at different positions Pn, where n represents different positions of the transmitting coil when it moves in the positive y-axis direction, and n is 2, 3, 4, … When the burial depth of the underground facility, as well as the magnetic permeability and conductivity are fixed, respectively establish the original databases A1 and A2 of the alternating magnetic field collected at different positions between the lowest point and the highest point of the receiving coil under the conditions that the transmitting frequency of the transmitting coil and the magnetic permeability and conductivity of the underground facility change respectively;

[0041] S2: On the material identification area of the underground facility, place the transmitting coil at the lowest position P1 on the ground, and move the transmitting coil within the identification area. Record the difference between the y-axis component of the alternating magnetic field obtained by the receiving coil and the y-axis component of the alternating magnetic field in the non-detection area. When the absolute value of the difference is the largest, record the horizontal position where the transmitting coil is located and the y-axis component By of the alternating magnetic field obtained by the receiving coil 测P1 ;

[0042] S3: Move the receiving coil from low to high, record the difference between the y-axis component and the y-axis component of the alternating magnetic field in the non-detection area during the process of the receiving coil moving from low to high, and perform normalization processing to obtain the normalized data. Establish a curve of the alternating magnetic field changing with frequency based on the normalized data;

[0043] S4: Compare the collected alternating magnetic field data with the original database A1 of the alternating magnetic field, select an alternating magnetic field curve with the highest curve trend coincidence degree changing with frequency, and determine the relative magnetic permeability of the underground facility; if the relative magnetic permeability of the underground facility is greater than 1.05, it is a ferromagnetic material. If the relative magnetic permeability of the underground facility is between 0.95 - 1.05, then compare the collected alternating magnetic field data with the original database A2 of the alternating magnetic field, select an alternating magnetic field curve with the highest curve trend coincidence degree changing with frequency, and determine the conductivity of the underground facility; if the conductivity σ of the underground facility > 10 5 S / m, it is a non-ferromagnetic material. If the conductivity σ of the underground facility ≤ 10 5 S / m, it is a non-metallic material.

[0044] Specifically, after determining the material type of the underground facility in S4, query the material manual corresponding to the material type to determine the specific material properties.

[0045] Specifically, the identification area and the non-identification area of the present invention are not the same area. The point P1 in the identification area and the non-identification area is not the same point. The non-identification area and the identification area do not cover and overlap. Specifically, when establishing a coordinate system, take the centers of the receiving coil 1 and the transmitting coil 2 as the coordinate origin. Preferably, take the ground as the reference, take the ground as the x-axis, and take the direction perpendicular to the ground as the y-axis direction. When selecting the measurement area and the non-measurement area, it is any point in the measurement area or the non-measurement area. When measuring in the measurement area, the position where the measurement area is located is fixed.

[0046] When moving the receiving coil in the identification area and the non-identification area, it is preferable to adopt the direction of the coordinate system established in the non-identification area. A separate coordinate system can also be established. However, the x-axis of the coordinate system is parallel to the ground direction, the y-axis is perpendicular to the ground direction, and the upward direction from the ground is the positive direction. The origin of the coordinate system is the center of the receiving coil 1 and the transmitting coil 2 in the identification area or the non-identification area. During the actual movement, the coordinate system also moves accordingly. However, when specifically measuring the y-axis component of the alternating magnetic field generated by the receiving coil 1 or the transmitting coil 2 at a specific position, the coordinate system is fixed.

[0047] Specifically, due to the height difference on the actual ground, the height difference between the grounds of the present invention is negligible. When moving the receiving coil 1, the transmitting coil 2 is in a fixed position and does not move anymore. That is, the measured data is obtained with the transmitting coil 2 fixed and the receiving coil 1 moving, and the data is measured based on the same center.

[0048] Preferably, the identified underground facility 3 is located directly below the receiving coil 1 and the transmitting coil 2, and the identified material is set underground. When identifying the material, it is necessary to determine the position and material properties of the underground facility 3 through the magnetic field components in the y-axis direction of the receiving coil 1 and the transmitting coil 2. That is, there is a difference in the magnetic field components in the y-axis direction when the receiving coil 1 and the transmitting coil 2 approach or move away from the underground facility 3. The best identification area of the underground facility 3 is determined according to the maximum and minimum values of the magnetic field components in the y-axis direction; preferably, when the magnetic field component in the y-axis direction is the largest when the receiving coil 1 moves within the identification area at the same height, it is default that the underground facility 3 is located directly below the receiving coil 1 and the transmitting coil 2.

[0049] Preferably, the positive direction of the x-axis is the right direction, and the positive direction of the y-axis is the upward direction from the ground, as Figure 2 shown.

[0050] Specifically, in an embodiment of the present invention, the set burial depth d of the underground facility is consistent with the calculated burial depth. The alternating magnetic field data compared with the original database are all normalized data. Specifically, the normalization process is to divide the initial data by the maximum value in the initial data set.

[0051] Preferably, the receiving coil moves at equal intervals between the lowest point and the highest point.

[0052] Specifically, the relationship between the radius r1 of the transmitting coil and the radius r2 of the receiving coil is: r1 > 0.5m, r2 < 0.2m.

[0053] Specifically, when judging the material of the underground facility, the burial depth of the underground facility is consistent with the calculated depth. And the burial depth d of the underground facility satisfies the following relationship:

[0054]

[0055] wherein, By 测P1 is the y-axis component of the alternating magnetic field when the receiving coil is in the initial position; By P1 is the y-axis component of the alternating magnetic field generated by the transmitting coil in the initial position; By 测Pn is the y-axis component of the alternating magnetic field when the receiving coil is in the highest position; By P1 is the y-axis component of the alternating magnetic field generated by the transmitting coil in the highest position; d1 is the straight-line distance between the receiving coil and the transmitting coil when the receiving coil moves in the positive y-axis direction.

[0056] Specifically, when the receiving coil is at the lowest point on the ground, the receiving coil is concentrically arranged inside the transmitting coil, and the receiving coil and the transmitting coil are in the same plane.

[0057] Specifically, in an example of the present invention, the method of the present invention is illustrated by taking 5 points where the receiving coil moves equidistantly from the lowest point to the highest point along the positive y-axis from P1 to P5. Specifically, the multi-frequency electromagnetic fusion type underground facility material identification device is placed in a non-detection area, the receiving coil is adjusted to the lowest position P1, the centers of the transmitting coil and the receiving coil coincide, the radius r1 of the transmitting coil is 0.5 m, the number of turns is 100, the effective value of the alternating current passed through is 10 A, the radius r2 of the receiving coil is 0.1 m, the number of turns is 100, and the y-axis component By P1 of the alternating magnetic field generated by the transmitting coil is recorded at this time. The receiving coil is vertically moved upward to P2, P3, P4, and P5 respectively, and the y-axis components By P2 、By P3 、By P4 、By P5 of the alternating magnetic field generated by the transmitting coil are recorded in sequence, and the straight-line distance d1 = 0.5 m from position P1 to P5, the specific positions of the transmitting coil and the receiving coil, and the moving direction of the receiving coil are as shown in Figure 2 shown.

[0058] Specifically, in this preferred embodiment, it is illustrated by taking the coils placed on the ground as an example. In actual detection, the transmitting coil can also be arranged on other insulating items on the ground, such as structures like plastic or nylon or foam boards, or on supports with a small distance from the ground, or the transmitting coil can be arranged in a pit dug underground. At the lowest position, the transmitting coil and the receiving coil are in the same plane, and preferably the receiving coil is arranged inside the transmitting coil. When the receiving coil is moved, it moves equidistantly along the positive y-axis. Preferably, the distance of each movement is 10 cm, and any distance between 5 - 15 cm can be selected as the distance of each movement of the receiving coil.

[0059] Secondly, an original database A1 of the alternating magnetic field collected by the receiving coil at different positions P1 - P5 is established when the burial depth and conductivity of the underground facility are fixed, and the transmitting frequency of the transmitting coil and the magnetic permeability of the underground facility vary respectively; an original database A2 of the alternating magnetic field collected by the receiving coil at different positions P1 - P5 is established when the burial depth and magnetic permeability of the underground facility are fixed, and the transmitting frequency of the transmitting coil and the conductivity of the underground facility vary respectively.

[0060] Then place the multi - frequency electromagnetic fusion type underground facility material identification device in the detection area, adjust the receiving coil to the lowest position P1, horizontally move the device, and record the difference between the y - axis component of the alternating magnetic field obtained by the receiving coil and the y - axis component of the alternating magnetic field in the non - detection area. When the absolute value of the difference is the largest, stop moving the device, and record the horizontal position of the device at this time and the y - axis component By of the alternating magnetic field obtained by the receiving coil. 测P1 ;

[0061] Specifically, in the embodiment of the present invention, the maximum absolute value of the difference in the y - axis component of the magnetic field is 46 μT.

[0062] Adjust the receiving coil to the highest position P5, and record the y - axis component By_meas(P5) of the alternating magnetic field obtained by the receiving coil at this time. Then the burial depth of the underground facility satisfies the following equation:

[0063] The variation curve of the magnetic field amplitude of the underground facility with the burial depth is as Figure 3 shown, satisfying the relationship that the magnetic field amplitude is inversely proportional to the square of the burial depth; in the preferred embodiment of the present invention, for example, the measured burial depth d of the underground facility is 0.52 m, and the actual burial depth d is 0.50 m, and the error in the vertical direction is less than 5%; move the receiving coil from bottom to top, record the differences between the y - axis components of the alternating magnetic fields obtained by the receiving coil at the five positions P1, P2, P3, P4, and P5 and the y - axis component of the alternating magnetic field in the non - detection area, and perform normalization processing; set the burial depth of the underground facility as d = 0.52 m, compare the collected alternating magnetic field data with the original database A1 of the alternating magnetic field, select the closest curve of the magnetic field varying with frequency, and determine the relative magnetic permeability of the underground facility. The variation curve of the alternating magnetic field amplitude with frequency and a partial response curve of the original database A1 are as Figure 4 shown.

[0064] For example, in the embodiment of the present invention, the relative magnetic permeability of the underground facility is close to 1, so it can be determined as a non - ferromagnetic material; if the magnetic permeability of the underground facility is significantly greater than 1, it can be determined as a ferromagnetic material, and the specific type can be determined by querying the magnetic permeability handbook; if the magnetic permeability of the underground facility is close to 1, compare the collected alternating magnetic field data with the original database A2 of the alternating magnetic field, select the closest curve of the alternating magnetic field varying with frequency, and determine the conductivity of the underground facility. The variation curve of the alternating magnetic field amplitude with frequency and a partial response curve of the original database A2 are asFigure 5 as shown; if the conductivity σ of the underground facility > 10 5 S / m, it can be determined as a metal facility, and the conductivity manual can be queried to determine the specific metal type; otherwise, it can be determined as a non-metal facility.

[0065] Specifically, the magnetic permeability is close to 1. Here, the proximity in the proximity range is preferably in the range of 1 ± 0.05, that is, when the magnetic permeability is between 0.95 and 1.05, it is necessary to assist in determining the material property of the underground facility by means of the conductivity of the material; specifically, the "significantly greater than 1" here means that the magnetic permeability of the underground facility is greater than 1.05, then the material of the underground facility is a ferromagnetic material.

[0066] For example, in the embodiment of the present invention, according to the response curve, it can be known that the conductivity σ of the underground facility > 10 5 S / m, it can be determined as a non-ferrous metal. Further, by comparing the consistency between the measured curve and the database curve, it is obtained that the conductivity of the underground facility is close to 6×10 7 S / m. According to the query result of the conductivity manual of metal materials, the conductivity of copper is close to 6×10 7 S / m. Therefore, it can be determined that the material of the underground facility is copper, that is, a copper facility.

[0067] By using the above method of the present invention, the finally obtained underground facility is a non-ferrous metal, and the specific material is copper. It can be seen that this method can effectively identify the material of the underground facility. By using a sine signal generation, amplification circuit and a transmitting coil to transmit a multi-frequency electromagnetic fusion signal, the position where the difference in the response amplitude of the alternating electromagnetic signal is the largest is used as the position for identifying the material of the underground facility; by detecting the buried depth of the underground facility and the response difference of the magnetic field amplitude signal with the transmitting frequency when the magnetic permeability and conductivity are different, and comparing the difference between the original alternating magnetic field standard database and the measured alternating magnetic field signal, the material of the underground facility is identified, solving the problem that it is difficult to identify the material of the underground facility and the need for excavation detection.

[0068] Embodiment 2

[0069] A multi-frequency electromagnetic fusion non-excavation underground facility material identification system, including

[0070] Non-identification area data acquisition module: used to place the transmitting coil at the lowest position P1 on the ground in the non-identification area of the underground facility material, and concentrically set the receiving coil with the transmitting coil. Taking the horizontal direction as the x-axis direction and the vertical direction as the y-axis direction, a two-dimensional coordinate system is established, and the y-axis component By of the alternating magnetic field generated by the transmitting coil is recorded P1 , move the receiving coil along the positive y-axis to different positions, and respectively record the y-axis component By of the alternating magnetic field generated by the transmitting coil at different positions Pn, where n represents different positions of the transmitting coil when it moves in the positive y-axis direction, and n = 2, 3, 4, … When the burial depth of the underground facility, as well as the permeability and conductivity are fixed, original databases A1 and A2 of the alternating magnetic field collected at different positions between the lowest and highest points of the receiving coil are established under the conditions that the transmitting frequency of the transmitting coil and the permeability and conductivity of the underground facility change respectively;

[0071] Identification area data acquisition module: used to place the transmitting coil at the lowest position P1 on the ground in the underground facility material identification area, and move the transmitting coil within the identification area, record the difference between the y-axis component of the alternating magnetic field obtained by the receiving coil and the y-axis component of the alternating magnetic field in the non-detection area. When the absolute value of the difference is the largest, record the horizontal position where the transmitting coil is located and the y-axis component By of the alternating magnetic field obtained by the receiving coil 测P1 ;

[0072] Data processing module: used to move the receiving coil from low to high, record the difference between the y-axis component and the y-axis component of the alternating magnetic field in the non-detection area during the process of the receiving coil moving from low to high, and perform normalization processing to obtain the normalized data, and establish a curve of the alternating magnetic field changing with frequency according to the normalized data;

[0073] Judgment module: used to compare the collected alternating magnetic field data with the original database A1 of the alternating magnetic field, select an alternating magnetic field curve with the highest coincidence degree of the curve trend to determine the relative permeability of the underground facility; if the relative permeability of the underground facility is greater than 1.05, it is a ferromagnetic material. If the relative permeability of the underground facility is between 0.95 - 1.05, then compare the collected alternating magnetic field data with the original database A2 of the alternating magnetic field, select an alternating magnetic field curve with the highest coincidence degree of the curve trend to determine the conductivity of the underground facility; if the conductivity σ of the underground facility > 10 5 S / m, it is a non-ferromagnetic material. If the conductivity σ of the underground facility ≤ 10 5 S / m, it is a non-metallic material.

[0074] Specifically, both the non-identification area data acquisition module and the identification area data acquisition module in a multi-frequency electromagnetic fusion non-excavation type underground facility material identification system of the present invention include: a sine signal generation module, which can generate an alternating voltage signal of 50 Hz - 50 kHz and is used to provide the transmission signal of the multi-frequency fusion device; a sine signal amplification module, which is used to amplify the sine voltage signal and enhance the stability of the multi-frequency electromagnetic fusion input signal; a sine signal transmission module, which is mainly an emission coil placed on a horizontal plane and is used to emit an alternating magnetic field required for identifying underground facilities to the ground; a sine signal reception module, which is mainly a miniaturized reception coil placed at the center of the emission coil, and the reception coil can be moved vertically to five positions P1 - P5 and is used to receive the change of the alternating magnetic field during the identification of underground facilities; a signal transmission module, which is mainly used to remove the noise in the received signal, improve the signal-to-noise ratio of the signal, and transmit the signal to the signal processing module; a signal processing module, which is based on the upper computer, analyzes and processes the original data according to the compiled algorithm, and compares it with the information in the alternating magnetic field original database to obtain relevant information such as the burial depth, relative magnetic permeability, and conductivity of the underground facilities.

[0075] The multi-frequency electromagnetic fusion non-excavation type underground facility material identification device of the embodiment of the present invention uses a sine signal generation, amplification circuit and an emission coil to emit a multi-frequency electromagnetic fusion signal, and takes the position where the difference in the response amplitude of the alternating electromagnetic signal is the largest as the position for identifying the material of the underground facility; by detecting the burial depth of the underground facility and the response difference of the magnetic field amplitude signal with the emission frequency when the magnetic permeability and conductivity are different, comparing the difference between the original alternating magnetic field standard database and the tested alternating magnetic field signal, so as to identify the material of the underground facility, and solves the problem that it is difficult to identify the material of underground facilities and excavation detection is required.

[0076] As is known by technical common sense, the present invention can be implemented by other embodiments that do not deviate from its spiritual essence or necessary features. Therefore, the above-disclosed embodiments are illustrative in all aspects and are not exclusive. All changes within the scope of the present invention or within the scope equivalent to the present invention are encompassed by the present invention.

[0077] 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 them. Although the present invention has been described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that: modifications or equivalent substitutions can still be made to the specific embodiments of the present invention, and any modification or equivalent substitution that does not deviate from the spirit and scope of the present invention should be covered by the protection scope of the claims of the present invention.

Claims

1. A multi-frequency electromagnetic fusion non-excavation method for identifying the materials of underground facilities, characterized in that including the following steps, S1: On the non-identifying area of the underground facility material, place the transmitting coil at the lowest position P1 on the ground, and concentrically set the receiving coil with the transmitting coil. Taking the horizontal direction as the x-axis direction and the vertical direction as the y-axis direction, and taking the center of the receiving coil and the transmitting coil as the coordinate origin, establish a two-dimensional coordinate system, and record the y-axis component By of the alternating magnetic field generated by the transmitting coil. P1 , move the receiving coil along the positive y-axis to different positions, and respectively record the y-axis component By of the alternating magnetic field generated by the transmitting coil at different positions. Pn , where n is the different positions where the transmitting coil is located when moving along the positive y-axis, and n is 2, 3, 4..., establish the original database A1 of the alternating magnetic field collected by the receiving coil at different positions between the lowest point and the highest point when the buried depth and conductivity of the underground facility are fixed and the transmitting frequency of the transmitting coil and the magnetic permeability of the underground facility change respectively; establish the original database A2 of the alternating magnetic field collected by the receiving coil at different positions between the lowest point and the highest point when the buried depth and magnetic permeability of the underground facility are fixed and the transmitting frequency of the transmitting coil and the conductivity of the underground facility change respectively. S2: On the underground facility material identification area, place the transmitting coil at the lowest position P1 on the ground, and move the transmitting coil within the identification area. Record the difference between the y-axis component of the alternating magnetic field obtained by the receiving coil and the y-axis component of the alternating magnetic field in the non-detection area. When the absolute value of the difference is the largest, record the horizontal position where the transmitting coil is located and the y-axis component By of the alternating magnetic field obtained by the receiving coil 测P1 ; S3: Move the receiving coil from low to high, record the difference between the y-axis component of the receiving coil and the y-axis component of the alternating magnetic field in the non-detection area during the process of the receiving coil moving from low to high, perform normalization processing to obtain the normalized data, and establish a curve of the alternating magnetic field varying with frequency according to the normalized data; S4: Compare the collected AC magnetic field data with the original AC magnetic field database A1, select an AC magnetic field vs. frequency curve with the same curve trend, determine the relative magnetic permeability of the underground facility, and determine the property of the underground facility material based on the magnetic permeability value. If the relative magnetic permeability of the underground facility is greater than 1.05, it is a ferromagnetic material; if the relative magnetic permeability of the underground facility is between 0.95 - 1.05, it is a non-ferromagnetic material. Compare the collected AC magnetic field data with the original AC magnetic field database A2, select an AC magnetic field vs. frequency curve with the same curve trend, and determine the conductivity of the underground facility. If the conductivity of the underground facility > 10 5 S / m, it is a metal material; if the conductivity of the underground facility ≤ 10 5 S / m, it is a non-metal material.

2. The multi-frequency electromagnetic fusion non-excavation type underground facility material identification method according to claim 1, wherein The receiving coil moves at equal intervals when moving between the lowest point and the highest point.

3. The multi-frequency electromagnetic fusion non-excavation underground facility material identification method according to claim 1, characterized in that, The relationship between the radius r1 of the transmitting coil and the radius r2 of the receiving coil is: r1 > 0.5m, r2 < 0.2m.

4. A method for identifying the material of non-excavated underground facilities by multi-frequency electromagnetic fusion according to claim 1, characterized in that The normalization processing is the process of dividing the initial data by the maximum value in the initial dataset together.

5. A method for identifying the material of underground facilities by multi-frequency electromagnetic fusion in a non-excavation manner according to claim 1, characterized in that When judging the material of underground facilities, the burial depth of the underground facilities is the same as the calculated depth.

6. The multi-frequency electromagnetic fusion non-excavation underground facility material identification method according to claim 1, wherein, The burial depth d of the underground facilities satisfies the following relationship: where d1 is the straight-line distance between the receiving coil and the transmitting coil when the receiving coil moves in the positive y-axis direction.

7. A method for identifying the material of underground facilities by multi-frequency electromagnetic fusion in a trenchless manner according to claim 1, characterized in that When the receiving coil is at the lowest point on the ground, the receiving coil is concentrically arranged inside the transmitting coil, and the receiving coil and the transmitting coil are in the same plane.

8. A method for identifying the material of non-excavated underground facilities by multi-frequency electromagnetic fusion according to claim 1, characterized in that, After the type of the material of the underground facilities is determined, the specific material type is determined by querying the material manual corresponding to the material type.

9. A multi-frequency electromagnetic fusion non-excavation type underground facility material identification system, characterized in that, including, Non-identification area data acquisition module: Used in the non-identification area of the underground facility material, place the transmitting coil at the lowest position P1 on the ground, set the receiving coil concentric with the transmitting coil, establish a two-dimensional coordinate system with the horizontal direction as the x-axis direction and the vertical direction as the y-axis direction, and record the y-axis component By of the alternating magnetic field generated by the transmitting coil P1 , move the receiving coil along the positive y-axis to different positions, and respectively record the y-axis component By of the alternating magnetic field generated by the transmitting coil at different positions Pn , where n is the different positions where the transmitting coil is located when moving along the positive y-axis, n is 2, 3, 4..., establish the original database A1 of the alternating magnetic field collected by the receiving coil at different positions between the lowest and highest points when the buried depth and conductivity of the underground facility are fixed and the transmitting frequency of the transmitting coil and the magnetic permeability of the underground facility change respectively; establish the original database A2 of the alternating magnetic field collected by the receiving coil at different positions between the lowest and highest points when the buried depth and magnetic permeability of the underground facility are fixed and the transmitting frequency of the transmitting coil and the conductivity of the underground facility change respectively Recognition area data acquisition module: Used in the underground facility material recognition area, place the transmitting coil at the lowest position P1 on the ground, and move the transmitting coil within the recognition area, record the difference between the y-axis component of the alternating magnetic field obtained by the receiving coil and the y-axis component of the alternating magnetic field in the non-detection area. When the absolute value of the difference is the largest, record the horizontal position where the transmitting coil is located and the y-axis component By of the alternating magnetic field obtained by the receiving coil 测P1 ; Data processing module: used to move the receiving coil from low to high, record the difference between the y-axis component of the receiving coil and the y-axis component of the alternating magnetic field in the non-detection area during the process of the receiving coil moving from low to high, perform normalization processing to obtain the normalized data, and establish a curve of the alternating magnetic field varying with frequency according to the normalized data; Judgment module: used to compare the collected AC magnetic field data with the original AC magnetic field database A1, select an AC magnetic field curve with the same curve trend as the frequency changes, determine the relative magnetic permeability of the underground facility, and determine the property of the underground facility material according to the magnitude of the magnetic permeability; if the relative magnetic permeability of the underground facility is greater than 1.05, it is a ferromagnetic material, if the relative magnetic permeability of the underground facility is between 0.95 and 1.05, it is a non-ferromagnetic material, compare the collected AC magnetic field data with the original AC magnetic field database A2, select an AC magnetic field curve with the same curve trend as the frequency changes, and determine the conductivity of the underground facility; if the conductivity of the underground facility > 10 5 S / m, it is a metal material, if the conductivity of the underground facility ≤ 10 5 S / m, it is a non-metal material.

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