Method for scanning detection by low-frequency electromagnetic resonance

Abstract

The application discloses a method for scanning and detecting by using low-frequency electromagnetic resonance, which comprises the following steps: propagating an electromagnetic beam condensed from a geomagnetic field along a straight line, and resonant scattering is generated when the electromagnetic beam encounters a material interface in the propagation process, and positioning and detecting are realized according to the scattered boundary magnetic anomaly caused by the resonant scattering. The application can realize the detection of a depth of 0.1-300 meters by using different specifications of probes, and the detection in underground tunnels and goaf has been verified by drilling many times. The detection of subtle flaws of cultural relics and engineering structures can be realized by amplifying the probe, and a cavity with a size of 1 cm and a crack with a width less than 1 cm can be described and positioned accurately. The horizontal scanning and detection of objects on the ground, including cultural relics, can be realized, and the internal structure of the detected object can be accurately scanned. The inherent low-frequency resonant electromagnetic wave of the object can be used to determine the material type, attribute shape and material of the concealed object, and self-rechecking and verification can be realized.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of geomagnetic detection, and particularly relates to a method for scanning detection by using low-frequency electromagnetic resonance. BACKGROUND

[0002] In the engineering detection process, the detection of underground concealed engineering is the main concern and problem to be solved by various detection equipment and technology. However, there are few corresponding means and technology for the non-destructive detection of the internal structure of ground objects including buildings and cultural relics. The existing radar, flaw detector and other equipment cannot achieve deep and accurate detection of ground objects. Similarly, the existing high-density electrical method, microseismic, transient electromagnetic method and other geophysical methods cannot achieve accurate detection of deep underground objects. Even within the effective detection range, precise detection cannot be achieved, and only local abnormal areas can be detected. At present, in the field of engineering detection, scanning detection similar to CT and nuclear magnetic resonance cannot be achieved.

[0003] At present, there is no mature and perfect technology for non-destructive detection of ground structures and cultural relics. Concrete flaw detection instruments are limited to concrete structure detection and have no targeted method for soil, rock and other materials. Due to the wavelength factor, the signal attenuation of ultrasonic detection and radar is serious, and the detection depth is limited. The detection depth of radar is 3-5 meters, and the detection depth of ultrasonic wave is shallower. The commonly used means for detecting underground, such as high-density electrical method, microseismic and transient electromagnetic method, cannot accurately describe the internal structure of the structure, and cannot detect the cavities and cracks in the internal structure of the detection object. The electromagnetic and surface wave combined detection technology and cosmic ray muon imaging technology have been tested in the detection of ground cultural relics. Due to the accuracy, they cannot be widely applied. In general, there is still no mature detection technology for non-destructive detection of ground structures and cultural relics. In addition, the commonly used radar equipment is not suitable for high-altitude wall movement operation due to the weight of the equipment.

[0004] Compared with the detection of ground structures, the detection means of underground concealed objects is relatively diverse, but there are still technical bottlenecks. The main problems are detection depth and accuracy. The current various detection means, such as radar, various electrical methods, magnetic methods, sound waves and even sonar, cannot achieve accurate detection of objects with a depth of more than 5 meters. The main reason is that the underground attenuation of various artificially emitted detection waves is serious, and the electromagnetic interference of the detection site is serious. At present, it is technically impossible to solve the problems of signal attenuation and anti-interference.

[0005] In order to perform scanning detection on ground or underground objects, the problem of fine detection must be solved first. Only when the detection accuracy is improved to the level of centimeter, the scanning of the detection object can be realized. Secondly, the problem of horizontal detection must be solved to realize the horizontal detection of ground objects and solve the problem of omnidirectional scanning. SUMMARY

[0006] The application provides a low-frequency electromagnetic wave resonance scanning detection technology, solves the above-mentioned industry problems, and realizes horizontal scanning and vertical scanning detection accurately, and realizes resonance scanning detection of objects on the ground and underground similar to CT technology.

[0007] The method for scanning and detecting by using low-frequency electromagnetic resonance comprises the following steps:

[0008] The electromagnetic beam condensed by the geomagnetic field is propagated along a straight line, and the electromagnetic beam encounters a material interface to produce resonance scattering in the propagation process, and the resonance scattering causes a scattered boundary magnetic anomaly to realize positioning detection.

[0009] Alternatively, the method for scanning and detecting by using low-frequency electromagnetic resonance comprises the following steps: the geomagnetic field is condensed into a beam by using a horizontal probe, the formed electromagnetic beam is propagated along a straight line, encounters a material interface to produce resonance scattering, the resonance scattering causes a scattered boundary magnetic anomaly, and the position of the magnetic anomaly is detected to realize positioning detection.

[0010] Alternatively, the method for scanning and detecting by using low-frequency electromagnetic resonance comprises the following steps: the geomagnetic field is condensed into a beam by using a horizontal probe, the formed electromagnetic beam is propagated along a straight line, encounters a material interface to produce resonance scattering, the resonance scattering causes a scattered boundary magnetic anomaly, and the position of the magnetic anomaly is detected to realize positioning detection.

[0011] Further, the geomagnetic field is condensed and the electromagnetic beam in the horizontal direction is formed at the detection point by using the horizontal probe.

[0012] Further, when the electromagnetic beam encounters a material interface of different magnetic resistance materials on the propagation path, low-frequency electromagnetic wave resonance scattering is produced, different low-frequency electromagnetic wave resonance scattering forms a cone shape, and a magnetic anomaly is caused at the scattering boundary, and the magnetic anomaly is detected by cutting the magnetic force line.

[0013] Further, the method for detecting the magnetic anomaly by cutting the magnetic force line is that the horizontal probe is used to control the included angle of low-frequency electromagnetic wave resonance scattering to obtain the following equation:

[0014] wherein the distance L from the horizontal probe to the anomaly point during detection, and the depth H of the interface are calculated.

[0015] Further, the horizontal probe is used to control the included angle of low-frequency electromagnetic wave resonance scattering , and , or .

[0016] Further, the resonance frequencies of different material interfaces are different.

[0017] Further, when scanning and detecting by using the horizontal probe, the horizontal probe is placed on the surface of the detected object to form a scanning point at an interval of 5cm-100cm for scanning, the interface depth of each scanning point is calculated, the interface detected by each detection point is a plurality of layers, then the structure shape inside the surface of the object is listed according to the interface depth of each detection point, and the material type between each layer interface is determined according to the material frequency signal characteristics.

[0018] The present application can realize the detection of 0.1-300m depth by using different specifications of probes, and has been verified by drilling many times in the detection of underground tunnels and goaf; the detection of subtle flaws of cultural relics and engineering structures can describe the 1cm-sized cavity and accurately locate the crack less than 1cm in width by using the magnifying probe; the horizontal scanning detection of above-ground objects including cultural relics can accurately scan the internal structure of the detected object; the inherent low-frequency resonant electromagnetic wave of the object can determine the material type, attribute shape and material of the concealed object in all directions, and can realize self-rechecking and verification. BRIEF DESCRIPTION OF DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiment description. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without any creative effort based on these drawings.

[0020] Figure 1 is the schematic diagram of the horizontal depth detection provided by the present application;

[0021] Figure 2 is the schematic diagram of the horizontal probe structure provided by the present application. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical solutions and advantages of the present application more clear, the following will further describe the embodiments of the present application in combination with the drawings.

[0023] The electromagnetic beam forming principle, resonant scattering principle and depth calculation model of the present application are explained as follows.

[0024] Electromagnetic beam forming principle: the geomagnetic field in the space above the ground can be approximately considered as homogeneous and static, according to the related theory, it can be concentrated into a beam due to the condensation effect, and propagates in a straight line in the form of an electromagnetic beam. This is the basis of the entire technology. The horizontal probe forms a horizontal electromagnetic beam at the detection point, which is based on the characteristics of the geomagnetic field, so that the electromagnetic beam can be used as a detection medium to propagate in space and interact with the measured object.

[0025] Resonance scattering principle: when electromagnetic beams encounter the interface of different magnetic resistance materials on the propagation path, low-frequency electromagnetic wave resonance scattering occurs. From the perspective of electromagnetism, the difference in magnetic resistance of different materials will cause changes in electromagnetic properties, which will interfere with the propagation of electromagnetic waves at the interface. According to the resonance principle, when the external excitation frequency is close to or equal to the natural frequency of the material or system, resonance will occur. At this time, the energy of the electromagnetic beam will interact with the material, producing strong scattering, and the scattering is conical, producing a magnetic anomaly at the scattering boundary.

[0026] Reference Figure 1 Depth calculation model: low-frequency electromagnetic wave resonance scattering occurs when electromagnetic beams encounter the interface of different objects. The form of resonance scattering is conical according to actual testing, and a magnetic anomaly is caused at the scattering boundary. This anomaly can be detected by cutting the magnetic force line.

[0027] Due to the angle of low-frequency electromagnetic wave resonance scattering can be controlled by a guide probe. In vertical detection on the ground, 45°, 22.5°, is usually selected for detection. The distance L from the probe to the anomaly point is measured, and the depth H of the interface is calculated through the trigonometric function . In horizontal scanning detection, a horizontal reinforcement probe with or is generally used. This probe can magnify the flaws in the structure of the detected object by two or four times, thereby improving the detection accuracy.

[0028] In actual detection, different resonance frequencies of different materials can be used for specific material detection according to the different types of underground materials, that is, different object frequency (intrinsic resonance electromagnetic frequency of the object) signal modes are used for scanning.

[0029] For example, in the detection of a certain ancient tower structure, hollow mode, Tang brick mode and filling mode are used for detection, respectively. The object frequency electromagnetic wave excitation of hollow, Tang brick and plain soil is used to induce its intrinsic resonance electromagnetic wave. This is because different objects have different electromagnetic properties and intrinsic frequencies (the intrinsic frequencies of different substances differ greatly, which can be measured according to the instrument). When the external electromagnetic excitation frequency matches the intrinsic frequency of these objects, low-frequency resonance (resonance) occurs. By detecting the electromagnetic wave produced by this resonance or the magnetic anomaly caused by it, the existence, position and distribution of the object can be determined, such as whether there are hollows, Tang bricks and filling in the tower.

[0030] When scanning, the horizontal probe is placed on the surface of the object to be detected, and scanning is performed at different intervals of 5 cm to 100 cm according to the accuracy requirement. The depth of different interfaces needs to be calculated in the detection process of each scanning point. The interface detected by each detection point can be multiple layers. Then, the structure shape inside the surface of the object is listed according to the data of each detection point, and the material type between each layer of interface is determined according to the material frequency signal characteristics (concrete, fill, cavity, crack, pipe diameter, wood material, Tang brick, and three-layered soil, etc.).

[0031] Due to the characteristics of the geomagnetic field itself, the guide probe is easy to gather the magnetic field to the underground electromagnetic beam, and it is difficult to gather the geomagnetic field to the horizontal electromagnetic beam. The application strengthens the guide function of the probe by using a composite coil and a composite material structure, and successfully realizes the formation of the horizontal electromagnetic beam of the geomagnetic field. The structure of the horizontal probe from the inside to the outside is a first magnetic material barrel 1, a first copper coil 2 arranged outside the first magnetic material barrel 1, a second magnetic material barrel 3 arranged outside the first copper coil 2, a second copper coil 4 arranged outside the second magnetic material barrel coil 3, and a glass outer cover 5 arranged outside the second copper coil 4. The first copper coil 2 and the second copper coil 4 are respectively provided with an excitation wire column. By applying excitation to the first copper coil 2 and / or the second copper coil 4 through the excitation wire column, the condensation effect is more obvious.

[0032] Based on the above basic theory, the application uses a horizontal probe to condense the geomagnetic field into a beam, the electromagnetic beam formed by the horizontal probe propagates along a straight line, resonant scattering occurs when the electromagnetic beam encounters different material interfaces, the resonant scattering causes scattering boundary magnetic anomalies, and positioning detection is realized by detecting the position of the magnetic anomalies.

[0033] The specific scheme is as follows:

[0034] The method for scanning and detecting by using low-frequency electromagnetic resonance includes the following steps:

[0035] The electromagnetic beam formed by condensing the geomagnetic field propagates along a straight line, resonant scattering occurs when the electromagnetic beam encounters material interfaces in the propagation process, and positioning detection is realized according to the scattering boundary magnetic anomalies caused by resonant scattering.

[0036] Alternatively, the method for scanning and detecting by using low-frequency electromagnetic resonance includes the following steps: using a horizontal probe to condense the geomagnetic field into a beam, the electromagnetic beam formed by the horizontal probe propagates along a straight line, resonant scattering occurs when the electromagnetic beam encounters material interfaces, resonant scattering causes scattering boundary magnetic anomalies, and positioning detection is realized by detecting the position of the magnetic anomalies.

[0037] Or, the method for scanning and detecting by using low-frequency electromagnetic resonance, comprising the following steps: condensing the geomagnetic field into a beam by using a horizontal probe, forming an electromagnetic beam propagating along a straight line, producing resonance scattering when encountering different material interfaces, causing resonance of the detected material by applying resonance frequencies of different materials, and producing resonance scattering to determine the type and properties of the detected material.

[0038] Further, the geomagnetic field is condensed at the detection point by using the horizontal probe to form an electromagnetic beam in the horizontal direction.

[0039] Further, when the electromagnetic beam encounters different material interfaces of different magnetic resistance materials on the propagation path, low-frequency electromagnetic wave resonance scattering is produced, different low-frequency electromagnetic wave resonance scattering forms a cone shape, and a magnetic anomaly is caused at the scattering boundary, and the magnetic anomaly is detected by cutting the magnetic force lines.

[0040] Further, the method for detecting the magnetic anomaly by cutting the magnetic force lines is to control the included angle of the low-frequency electromagnetic wave resonance scattering by using the horizontal probe to obtain the following equation:

[0041] wherein L is the distance from the horizontal probe to the anomaly point during detection, and H is the depth of the interface.

[0042] Further, the included angle of the low-frequency electromagnetic wave resonance scattering by using the horizontal probe is controlled, and =2, or .

[0043] Further, the resonance frequencies of different material interfaces are different.

[0044] Further, when scanning and detecting by using the horizontal probe, the horizontal probe is placed on the surface of the detected object to form a scanning point at an interval of 1cm-100cm for scanning, the interface depth of each scanning point is calculated, the interface detected at each detection point is multi-layered, then the structure shape inside the object surface is listed according to the interface depth of each detection point, and the material type between each interface is determined according to the material frequency signal characteristics.

[0045] The present application can realize detection of 0.1-300 meters in depth by using different specifications of probes, and has been verified by drilling multiple times in the detection of underground tunnels and goaf; the detection of subtle flaws of cultural relics and engineering structures can describe 1cm-sized cavities and the like by using an enlarged probe, and accurately locate cracks less than 1cm wide; horizontal scanning and detection of objects on the ground including cultural relics can accurately scan the internal structure of the detected object; the inherent low-frequency resonance electromagnetic wave of the object can determine the material type, properties, shape and material of the concealed object, and can realize self-rechecking and verification.

[0046] The above description is only the preferred embodiment of the present application, and is not intended to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for scanning detection using low-frequency electromagnetic resonance, characterized in that, Includes the following steps: The electromagnetic beam formed by condensing the Earth's magnetic field propagates in a straight line. When the electromagnetic beam encounters a material interface during propagation, it generates resonant scattering. The location detection is achieved by using the magnetic anomaly at the scattering boundary caused by the resonant scattering. A horizontal probe is used to concentrate the Earth's magnetic field at the detection point and form a horizontal electromagnetic beam. When an electromagnetic beam encounters a material interface of different magnetoresistive materials in its propagation path, it will generate low-frequency electromagnetic wave resonant scattering. The different low-frequency electromagnetic wave resonant scattering patterns are conical and cause magnetic anomalies at the scattering boundary. Magnetic anomalies can be detected by cutting magnetic field lines. The method for detecting magnetic anomalies by cutting magnetic field lines is as follows: The angle of low-frequency electromagnetic wave resonant scattering using a horizontal probe By applying control, the following equation is obtained: The process involves determining the distance L from the horizontal probe to the anomaly point during detection, and calculating the interface depth H. When using the horizontal probe for scanning detection, the horizontal probe is placed on the surface of the object to be detected, and a scanning point is formed at intervals of 1cm to 100cm for scanning. The interface depth of each scanning point is calculated. The interface detected at each detection point consists of multiple layers. Then, based on the interface depth of each detection point, the structural shape within the object surface is outlined, and the material type between each interface layer is determined based on the material frequency signal characteristics of the material.

2. The method for scanning detection using low-frequency electromagnetic resonance according to claim 1, characterized in that, The process includes the following steps: using a horizontal positioning and guiding probe to concentrate the geomagnetic field into a beam, the resulting electromagnetic beam propagates in a straight line, and when it encounters a material interface, it generates resonant scattering. The resonant scattering causes magnetic anomalies at the scattering boundary, and the positioning detection is achieved by detecting the location of the magnetic anomalies.

3. The method for scanning detection using low-frequency electromagnetic resonance according to claim 1 includes the following steps: using a horizontal probe to concentrate the geomagnetic field into a beam, the formed electromagnetic beam propagates in a straight line, and generates resonant scattering when it encounters different material interfaces, and by applying the resonant frequency of different materials to induce resonance in the material being detected, and generating resonant scattering, thereby determining the type and properties of the material being detected.

4. The method for scanning detection using low-frequency electromagnetic resonance according to claim 1, characterized in that, The angle of low-frequency electromagnetic wave resonant scattering using a horizontal probe To control and make , or .

5. The method for scanning detection using low-frequency electromagnetic resonance according to claim 1, characterized in that, Different material interfaces have different resonant frequencies.

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