Geomagnetic fine detection method

Abstract

The invention relates to the technical field of detection, in particular to a geomagnetic fine detection method, which comprises the following steps of: determining an object to be detected and an inherent electromagnetic wave resonance frequency of the object to be detected; the detection device is perpendicular to the to-be-detected object and moves at a constant speed to obtain magnetic field change information, and the specific position of the to-be-detected object is judged according to magnetic field induction change. According to the method, the stability of a natural geomagnetic field is utilized, magnetic resistance can be generated due to the difference of magnetic permeability of various substances, so that the phenomenon of magnetic overflow or convergence is generated on the earth surface, and existence and distribution conditions of ground fissures, cavities and various underground pipelines are determined by detecting geomagnetic anomalies; the abnormality is found by testing the change of induced electromotive force voltage generated when the conductor cuts the magnetic line of force; and determining the type and depth of the magnetic anomaly substance by using the substance frequency characteristics of various substances.

Description

Technical Field

[0001] The present invention relates to the field of detection technology, and in particular to a method for fine geomagnetic detection. Background Art

[0002] In rock and soil detection technology, there are detections of ground fissures, building settlement cracks, underground cavities, stratum structure surfaces, landslide structure surfaces, groundwater depth, underground pipelines and the length of cast-in-place pile reinforcement. These detections traditionally have a set of detection technologies, and these detection technologies are not related to each other and cannot form a unified detection science.

[0003] For example, traditional ground fissure detection mainly relies on drilling rig sampling and using the method of stratigraphic comparison to make judgments. In fact, the theory of faults is introduced into ground fissures. The existing geophysical exploration methods have large errors and are not recognized by everyone. The latest method is to use ground penetrating radar. By receiving and analyzing the reflected electromagnetic wave signals, the abnormal response of the cracks on the radar image can be clearly presented, which is convenient for locating and analyzing the morphology of the cracks. Based on the current technical level, the detection depth is limited; there is no effective and accurate detection method for underground cavities, especially those with a depth of more than 5 meters.

[0004] Building foundation settlement and crack detection is difficult to implement using traditional methods because there are no drilling conditions near the building.

[0005] There are many types of underground pipelines, including gas, water supply, heat, rainwater, sewage, electricity, optical cables, and cement pipes. Different pipelines are intertwined with each other, and the use of ground penetrating radar in the detection technology itself has difficulties and defects in signal interpretation and identification, which is not conducive to identifying which pipeline it is.

[0006] Pile body inspection mainly relies on "small strain" to detect the integrity of the pile body. By applying vibration waves and using the speed of high-frequency waves reflected by the structural surface, the length of the pile and the location of the interlayer and broken piles are calculated. Since vibration waves are elastic waves, the pile body needs to reach a certain strength and a certain age, which generally takes 21 days, and the inspection time is too long.

[0007] The latest method for measuring the length of cast-in-place pile reinforcement is to use a gaussmeter to observe the slight changes in the geomagnetic field around the pile and infer the length of the reinforcement in the cast-in-place pile. The principle is that the magnetic permeability of the reinforcement is high, and iron has a similar "adsorption effect" on the magnetic field, which weakens the magnetic field around the reinforcement and increases the magnetic field strength where there is no reinforcement. The disadvantage is that a detection hole must be drilled in the pile body or the side of the pile, and a gaussmeter must be placed to measure the geomagnetic strength.

[0008] Groundwater level detection. At present, groundwater level detection is mainly based on on-site measurement. The precipitation test of exploration requires the main well to measure the water level alone or in conjunction with the observation hole to measure the water level to understand the distribution of precipitation funnels. For seepage and immersion tests, the location of the water table can be indirectly determined by burying sensors. The disadvantage is that it requires the construction of observation wells or the burying of sensors, which is expensive. Summary of the invention

[0009] In order to solve the problems of the prior art, the present invention provides a method for detecting the position of an object to be detected by combining geomagnetism with electromagnetic induction.

[0010] Its main technical solutions are as follows: The present invention provides a method for fine geomagnetic detection, comprising the following steps: Determine the object to be tested and the electromagnetic wave resonance frequency inherent to the object to be tested; The detection device is moved at a constant speed perpendicular to the object to be measured to obtain the magnetic field change information, and the specific position of the object to be measured is determined according to the magnetic field change; After obtaining the specific position of the object to be measured, a low-frequency resonant electromagnetic wave corresponding to the inherent electromagnetic wave resonance frequency of the object to be measured is sent to one end of the object to be measured through an electromagnetic wave transmitter, and the object to be measured is identified based on whether a reflected signal corresponding to the low-frequency resonant electromagnetic wave can be received; and the depth of the object to be measured is calculated based on the receiving position of the reflected signal and the initial position of the magnetic field change obtained when the detection device moves at a constant speed perpendicular to the object to be measured.

[0011] Further, the following steps are included: Determine the object to be tested and the electromagnetic wave resonance frequency inherent to the object to be tested; The electromagnetic coil is coupled to the measuring circuit, and the electromagnetic coil is moved at a constant speed perpendicular to the object to be measured to obtain and record the real-time induced electromotive force or induced current, and the specific position of the object to be measured is determined according to the change of the induced electromotive force or induced current; After obtaining the specific position of the object to be measured, a low-frequency resonant electromagnetic wave corresponding to the inherent electromagnetic wave resonance frequency of the object to be measured is sent to the object to be measured through an electromagnetic wave transmitter, and the object to be measured is identified based on whether a reflected signal corresponding to the low-frequency resonant electromagnetic wave can be received; and the depth of the object to be measured is calculated based on the receiving position of the reflected signal and the initial position of the magnetic field change obtained when the detection device moves at a constant speed perpendicular to the object to be measured.

[0012] Furthermore, the detection device comprises a transverse conductor and a conductor handle arranged perpendicularly to the transverse conductor, a screw cap is arranged at one end of the transverse conductor, and a top end of the conductor handle is connected to one end of the transverse conductor through the screw cap; A capacitor box is arranged on the transverse conductor, a capacitor is arranged in the capacitor box, and an input end and an output end of the capacitor are respectively connected to the conductor handle and the transverse conductor through a wire to enhance the sensitivity of detection; The detection device is moved at a constant speed perpendicular to the direction of the object to be detected to obtain the deflection state of the two transverse conductors, and the specific position of the object to be detected is determined according to the deflection state of the two transverse conductors.

[0013] Furthermore, a detection device is held by the left hand and the right hand of the human body respectively, so that the transverse conductors in the two detection devices are in a parallel state, and an electromagnetic induction conductor is formed by holding a detection device by the left hand and the right hand of the human body respectively.

[0014] Furthermore, the human body is used as a body capacitor, and the body capacitor is connected in series with the capacitor by touching the wire arranged on the conductor handle by the human hand, thereby increasing the intensity of the transverse conductor in cutting the magnetic flux lines.

[0015] Furthermore, when the detection device is moved at a constant speed perpendicular to the direction of the object to be detected, when the object to be detected is detected, the lateral conductors located on the left hand and the right hand attract each other to form a deflection.

[0016] Furthermore, when the lateral conductors located in the left hand and the right hand attract each other to form a pendulum, the position of the person and the angle of the pendulum are recorded, and the specific position of the object to be measured is obtained by recording the position of the person moving and the angle of the pendulum.

[0017] Furthermore, when moving, the induced electromotive force or the induced current is recorded by a measuring circuit coupled to the electromagnetic coil, and the specific position of the object to be measured is determined according to the change curve of the induced electromotive force or the induced current.

[0018] Furthermore, the measuring circuit at least comprises: An amplifier circuit, composed of one or more amplifiers connected in series, coupled to the electromagnetic coil, for amplifying the electromotive force signal or current signal generated by the electromagnetic coil cutting the magnetic flux lines; The measuring element is connected to the amplifier circuit and is used to measure the amplified induced electromotive force or induced current.

[0019] Furthermore, the specific position of the object to be measured is determined according to the peak formed by the variation curve of the induced electromotive force or the induced current.

[0020] An application of a geomagnetic fine detection method is used to detect the location of ground fissures.

[0021] An application of a geomagnetic fine detection method is used to detect the location of underground pipelines.

[0022] An application of a geomagnetic fine detection method is used to detect the location of building cracks.

[0023] An application of a geomagnetic fine detection method is used to detect groundwater levels.

[0024] An application of a geomagnetic fine detection method is used to detect pile bodies and / or the length of cast-in-place pile reinforcement bars.

[0025] Compared with the prior art, the present invention has the following beneficial effects: This application uses the stability of the natural geomagnetic field. Due to the difference in magnetic permeability of various materials, magnetic resistance will be generated, resulting in magnetic overflow or convergence on the surface. By detecting geomagnetic anomalies, the existence and distribution of ground fissures, cavities, and various underground pipelines are determined. This anomaly is discovered by testing the changes in the induced electromotive force voltage generated by the conductor cutting the magnetic lines of force. The type and depth of magnetic anomaly materials are determined by using the material-frequency characteristics of various materials.

[0026] This application uses the combination of geomagnetism and electromagnetic induction to detect the position of the object to be detected, which is an interdisciplinary subject between geomagnetism and electromagnetic induction. And the combination of geomagnetism and electromagnetic induction technology is used to detect different types of detection objects, unifying the methods of detecting ground fissures, cavities, various underground pipelines, crack positions of building components, building foundation settlement, groundwater level, pile body detection and / or cast-in-place pile steel bar length. Thereby, a new theoretical system is essentially provided, enriching the combined application between geomagnetism and electromagnetic induction.

[0027] This application provides two paths to achieve detection. One is a mechanical method, that is, using a mechanical detection device to cut magnetic lines of force to achieve detection. The other is a method of using an electromagnetic coil to cut magnetic lines of force. By obtaining the induced electromotive force or induced current generated by the electromagnetic coil cutting the magnetic lines of force, the specific position of the object to be measured is determined according to the change curve of the induced electromotive force or induced current.

[0028] Although the above two paths are essentially different, they are both implemented by combining geomagnetism with electromagnetic induction technology and are consistent in principle. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0030] Figure 1 It is a theoretical diagram of magnetic field line overflow of ground fissures provided by the present invention; Figure 2 It is a theoretical model for ground fissure or cavity detection provided by the present invention; Figure 3 It is a theoretical diagram of magnetic flux overflow of a plastic pipeline provided by the present invention; Figure 4 It is a theoretical diagram of magnetic flux overflow of a metal pipeline provided by the present invention; Figure 5 It is a structural schematic diagram of the detection device provided by the present invention. DETAILED DESCRIPTION

[0031] In order to make the objectives, technical solutions and advantages of the present invention more clear, the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0032] The principle of geomagnetic detection is to use the stability of the natural geomagnetic field. The difference in magnetic permeability of various materials will produce magnetic resistance, resulting in magnetic overflow or convergence on the surface. The existence and distribution of ground fissures can be determined by detecting geomagnetic anomalies. At present, this anomaly is discovered by testing the changes in the induced electromotive force voltage generated by the conductor cutting the magnetic lines of force.

[0033] The theoretical basis of geomagnetic detection is based on the mature metal flaw detection theory. During the metal casting process, bubbles are generated in the castings. The magnetic permeability of iron is 2000H / m, and the magnetic permeability of air is 1H / m. When an artificial magnetic field is added, magnetic lines of force will overflow at the bubble location. The location of the bubble is determined by measuring the change in the magnetic field. The latest artificial intelligence diagnosis of wire rope fracture is based on the application of the same theory. The theoretical basis of geomagnetic detection is to treat rock and soil and various pipelines as a magnetic material, and use the difference in their magnetic permeability to identify various underground anomalies, and ultimately achieve the purpose of detection.

[0034] Different materials have different magnetic permeabilities and different electromagnetic wave resonance frequencies. Therefore, the present application utilizes the magnetic field line anomalies caused by the differences in magnetic permeabilities between different objects, thereby determining the positions of different objects by measuring magnetic field changes; and by applying different object frequency signals (the inherent electromagnetic wave resonance frequencies of various objects), the type and depth of the underground object being detected can be identified.

[0035] Example 1, reference Figure 5 In view of the above theory, the present application provides a method for fine geomagnetic detection, comprising the following steps: Determine the various frequencies of the object to be tested and the inherent electromagnetic waves of the object to be tested; The detection device is moved at a constant speed perpendicular to the object to be measured to obtain the change of the magnetic field, and the specific position of the object to be measured is determined according to the change of the magnetic field; After obtaining the specific position of the object to be measured, a low-frequency resonant electromagnetic wave corresponding to the inherent electromagnetic wave resonance frequency of the object to be measured is sent to one end of the object to be measured through an electromagnetic wave transmitter, and the object to be measured is identified based on whether a reflected signal corresponding to the low-frequency resonant electromagnetic wave can be received; and the depth of the object to be measured is calculated based on the receiving position of the reflected signal and the initial position of the magnetic field change obtained when the detection device moves at a constant speed perpendicular to the object to be measured.

[0036] In some embodiments, the detection device includes a transverse conductor 3 and a conductor handle 1 disposed perpendicularly to the transverse conductor 3, a screw cap 4 is disposed at one end of the transverse conductor 3, and the top end of the conductor handle 1 is connected to one end of the transverse conductor 3 through the screw cap 4; A capacitor box 2 is arranged on the transverse conductor 3, a capacitor is arranged in the capacitor box 2, and the input end and the output end of the capacitor 2 are respectively connected to the conductor handle 1 and the transverse conductor 3 through wires to enhance the sensitivity of detection; The detection device assists the artificial magnetic field to move at a uniform speed perpendicular to the direction of the object to be detected to obtain the deflection state of the two transverse conductors 3, and the specific position of the object to be detected is determined according to the deflection state of the two transverse conductors 3.

[0037] In some embodiments, a detection device is held by the left hand and the right hand of the human body respectively, so that the transverse conductors in the two detection devices are in a parallel state, and an electromagnetic induction conductor is formed by holding a detection device by the left hand and the right hand of the human body respectively.

[0038] In some embodiments, the human body is used as a body capacitor, and the body capacitor is connected in series with the capacitor by touching the wire disposed on the conductor handle with a human hand, thereby increasing the strength of the transverse conductor in cutting the magnetic flux lines.

[0039] In some embodiments, when the detection device assists the artificial magnetic field to move at a constant speed perpendicular to the direction of the object to be detected, when the object to be detected is detected, the lateral conductors located on the left hand and the right hand attract each other to form a pendulum.

[0040] In some embodiments, when the lateral conductors located in the left hand and the right hand attract each other to form a pendulum, the position of the person and the angle of the pendulum are recorded, and the specific position of the object to be measured is obtained by recording the position of the person moving and the angle of the pendulum.

[0041] In some embodiments, the present application does not necessarily require the detection device to be moved at a constant speed perpendicular to the direction of the object to be measured, but it can be moved approximately perpendicularly or at a certain angle to the object to be measured. When the detection device is moved at a constant speed along the direction of the object to be measured, there will be no cutting of magnetic flux lines. Therefore, in theory, it only needs to produce a certain angle with the object to be measured. In order to facilitate the implementation of the present application, in the present application, the detection device is moved at a constant speed perpendicular to the direction of the object to be measured, or the detection device is moved at a constant speed approximately perpendicular to the direction of the object to be measured, so that the phenomenon of obvious cutting of magnetic flux lines can be produced.

[0042] In some embodiments, the transverse conductors and the conductor handles may be made of a metal with strong conductive properties, such as copper.

[0043] In some embodiments, a scale is provided at the top of the conductor handle and at the rotation connection with the screw cap. The deflection state of the transverse conductor is obtained by observing the angle of the transverse conductor during the deflection process.

[0044] In some embodiments, when a person is used as a body capacitor, since different people have large differences in body capacitors, and in the present application, the role of the capacitor is to provide additional excitation to cause a stronger electromagnetic induction phenomenon, the capacitor box can be set as a device with adjustable capacitance, which is used to generate different additional excitations to cause electromagnetic induction phenomena of different intensities.

[0045] Embodiment 2, the present invention provides a method for fine geomagnetic detection, comprising the following steps: Determine the electromagnetic wave resonance frequency inherent to the object to be tested and the object to be tested; The electromagnetic coil is coupled to the measuring circuit, and the electromagnetic coil is manually moved at a constant speed perpendicular to the object to be measured to obtain and record the real-time induced electromotive force or induced current, and the specific position of the object to be measured is determined according to the change of the induced electromotive force or induced current; After obtaining the specific position of the object to be measured, a low-frequency resonant electromagnetic wave corresponding to the inherent electromagnetic wave resonance frequency of the object to be measured is sent to one end of the object to be measured through an electromagnetic wave transmitter, and the object to be measured is identified based on whether a reflected signal corresponding to the low-frequency resonant electromagnetic wave can be received; and the depth of the object to be measured is calculated based on the receiving position of the reflected signal and the initial position of the magnetic field change obtained when the detection device moves at a constant speed perpendicular to the object to be measured.

[0046] Furthermore, when moving, the induced electromotive force or the induced current is recorded by a measuring circuit coupled to the electromagnetic coil, and the specific position of the object to be measured is determined according to the change curve of the induced electromotive force or the induced current.

[0047] Furthermore, the measuring circuit at least comprises: An amplifier circuit, composed of one or more amplifiers connected in series, coupled to the electromagnetic coil, for amplifying the electromotive force signal or current signal generated by the electromagnetic coil cutting the magnetic flux lines; The measuring element is connected to the amplifier circuit and is used to measure the amplified induced electromotive force or induced current.

[0048] Furthermore, the specific position of the object to be measured is determined according to the peak formed by the variation curve of the induced electromotive force or the induced current.

[0049] In the above, the measuring circuit can be assembled by using commercially available components, and any components can be used as long as they can achieve the above purpose.

[0050] Example 3, reference Figure 1 , an application of a geomagnetic fine detection method, is used to detect the location of ground fissures.

[0051] The theoretical basis for the above method to be used in the detection of ground fissures and cavities is to treat rock and soil as materials, so that rock and soil not only have mechanical characteristics but also electromagnetic characteristics. That is to say, when rock and soil are regarded as magnetic bodies, they have a certain magnetic permeability. The buried objects in the soil have a different magnetic permeability from the soil. When the geomagnetic field encounters different objects, it will overflow and converge on the ground, that is, the uniform magnetic lines will overflow or converge downward, and the electromagnetic induction conductor will generate an induced electromotive force when it moves on the ground where the magnetic lines overflow. In this application, the difference in magnetic permeability between rock and soil and air is used. When the detection device is used to walk at a constant speed roughly vertically (or at a certain angle) on the ground, if there is no cavity or ground fissure, then the transverse conductors located on the left and right hands will not attract each other and thus deflect toward each other (that is, the magnetic lines of force do not change significantly). However, once there is a cavity or ground fissure, when walking near the cavity or ground fissure, the transverse conductors located on the left and right hands will attract each other and deflect toward each other. When reaching directly above the cavity or ground fissure, the deflection is most obvious (that is, the magnetic lines of force have obvious changes). Generally speaking, when reaching directly above the cavity or ground fissure, the magnetic lines of force have obvious magnetic lines of force overflow. Due to the overflow of magnetic lines of force, the position of the cavity or ground fissure can be obtained by measuring the change in the magnetic field.

[0052] The above describes the principle of the mechanical method, and the method of cutting magnetic flux lines using electromagnetic coils is also applicable.

[0053] It should be noted that the present application utilizes a combination of geomagnetism and electromagnetic induction technology to measure the location of cavities or ground fissures. It only requires a person to walk back and forth on the ground with a detection device, and there is no need to drill holes to analyze geological data.

[0054] Reference Figure 2 , Figure 2A theoretical model for ground fissure or cavity detection is given. Using the theoretical model for ground fissure or cavity detection, the depth of the ground fissure or cavity can be calculated, and the width can be calculated based on the deflection angle caused by the lateral conductors in two detection devices moving toward each other in the natural magnetic field.

[0055] Specifically, when the detection device is moved at a constant speed perpendicular to the object to be detected to obtain the magnetic field change, the initial position when the anomaly occurs and the range of the abnormal position are recorded. The range of the abnormal position is roughly the width of the ground fissure or cavity.

[0056] When sending low-frequency resonant electromagnetic waves, the depth of the object to be measured is calculated based on the receiving position of the reflected signal and the initial position of the magnetic field change obtained when the detection device moves at a constant speed perpendicular to the object to be measured.

[0057] in, Figure 2 In the figure, the distance between the transmitting end of the low-frequency resonant electromagnetic wave and the receiving end of the transmitted signal is L. Since the diffusion angle of the low-frequency resonant electromagnetic wave when reflected by the object to be measured is 90°, the depth H can be directly obtained as L / 2 according to the algorithm of the side length of the isosceles right triangle.

[0058] In this embodiment, the inherent electromagnetic wave resonance frequency of the ground fissure or cavity is 650-750 Hz.

[0059] Example 4, reference Figure 3 and Figure 4 , an application of geomagnetic precision detection method, is used to detect the location of underground pipelines.

[0060] Underground pipelines are relatively complex, such as metal pipes, plastic pipes, cement pipes, and wires and cables, etc. It is difficult to distinguish the above various data information using ground penetrating radar. Using the theory of this application, different objects have different electromagnetic wave resonance frequencies. When it is necessary to know what object to measure, it is necessary to apply the inherent electromagnetic wave resonance frequency of the object, and the same method in Example 3 can be used for measurement.

[0061] It should be noted that plastic pipes and cement pipes have the phenomenon of magnetic force lines overflowing, while metal pipes have the phenomenon of magnetic force lines converging. Different objects have certain differences in the performance of magnetic force lines. However, it does not affect the specific implementation.

[0062] It should also be noted that for the superposition detection of underground pipelines, that is, the staggered detection of different pipelines, its theoretical basis is the same as that of Example 3 in the present application. Specifically, the width and position are determined by the natural magnetic field; the depth and material are measured by additionally stimulating electromagnetic waves of different physical frequencies (different materials have different additional excitations, thereby distinguishing them).

[0063] It should also be noted that the present application can also detect the direction of different pipelines. Since the cutting magnetic flux lines must have a certain angle with the object to be measured, when they are parallel to the pipeline to be measured, the phenomenon of cutting magnetic flux lines will not occur.

[0064] In this embodiment, the inherent electromagnetic wave resonance frequency of iron is 16000-17000Hz, the inherent electromagnetic wave resonance frequency of plastic pipe is 730-760Hz, the inherent electromagnetic wave resonance frequency of steel bar is 16500-17000Hz, the inherent electromagnetic wave resonance frequency of copper is 11500-12000Hz, and the inherent electromagnetic wave resonance frequency of cement is 750-850Hz. The inherent electromagnetic wave resonance frequency of water is 10000Hz. The inherent electromagnetic wave resonance frequencies of different substances can be measured by instruments.

[0065] Example 5, an application of a geomagnetic precision detection method for detecting the location of building cracks and foundation settlement.

[0066] It should be noted that the present application is not limited to the detection of foundation settlement. Slope settlement and geological settlement during geological settlement detection can be measured using the present application.

[0067] It should be noted that foundation settlement, slope settlement, and geological settlement will all produce certain cracks or cavities. Therefore, the principles used in detecting the location of building cracks and foundation settlement are the same as those of Example 3.

[0068] In addition, the sedimentation caused by the dewatering of the foundation pit and the investigation of the sedimentation range can effectively treat the building defects. Through the analysis of the tendency of ground fissures, it can help the identification of dangerous buildings and analyze the causes of sedimentation and deformation. For example, whether it is a sedimentation feature or a slip feature, different features have different treatment methods.

[0069] Example 6, application of a geomagnetic precision detection method for detecting groundwater levels.

[0070] The principle of this embodiment is the same as that of embodiment 3. The detection of groundwater level helps to understand the pumping well and groundwater level changes, which is beneficial to the protection of groundwater resources.

[0071] Example 7, an application of a geomagnetic fine detection method for realizing pile body detection and / or detection of cast-in-place pile reinforcement length.

[0072] Since cement, steel bars and soil have different magnetic permeabilities and electromagnetic wave resonance frequencies, the present application can use the principle of Example 3 to detect the length of the steel bars of the above-mentioned cast-in-place piles, and can also detect the pile body, such as whether there are cracks in the pile body.

[0073] Compared with the traditional technology, the present application does not require drilling and does not affect the foundation around the cast-in-place piles.

[0074] This application uses the stability of the natural geomagnetic field. Due to the difference in magnetic permeability of various materials, magnetic resistance will be generated, resulting in magnetic overflow or convergence on the surface. By detecting geomagnetic anomalies, the existence and distribution of ground fissures, cavities, and various underground pipelines are determined. This anomaly is discovered by testing the changes in the induced electromotive force voltage generated by the conductor cutting the magnetic lines of force. The material frequency characteristics (inherent electromagnetic wave resonance frequency) of various materials are used to determine the type and depth of magnetic anomaly materials.

[0075] This application uses the combination of geomagnetism and electromagnetic induction to detect the position of the object to be detected, which is an interdisciplinary subject between geomagnetism and electromagnetic induction. And the combination of geomagnetism and electromagnetic induction technology can realize the detection of different types of detection objects, unifying the detection methods of ground fissures, cavities, underground pipelines, building crack positions, building foundation settlement, groundwater level, pile body detection and / or cast-in-place pile steel bar length. Thus, a new theoretical system is provided, enriching the combined application between geomagnetism and electromagnetic induction.

[0076] This application provides two paths to achieve detection. One is a mechanical method that uses a detection device to assist in an artificial magnetic field to achieve detection. The other is a method that uses an electromagnetic coil to cut magnetic lines of flux. The induced electromotive force or induced current generated by the electromagnetic coil cutting the magnetic lines of flux is obtained, and the specific position of the object to be measured is determined based on the change curve of the induced electromotive force or induced current.

[0077] Although the above two paths are essentially different, they are both implemented by combining geomagnetism with electromagnetic induction technology and are consistent in principle.

[0078] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for fine geomagnetic detection, characterized in that: The steps include: Determine the object to be tested and the electromagnetic wave resonance frequency inherent to the object to be tested; The detection device is moved at a constant speed perpendicular to the object to be measured to obtain the magnetic field change information, and the specific position of the object to be measured is determined according to the magnetic field change; After obtaining the specific position of the object to be measured, a low-frequency resonant electromagnetic wave corresponding to the inherent electromagnetic wave resonance frequency of the object to be measured is sent to one end of the object to be measured through an electromagnetic wave transmitter, and the object to be measured is identified based on whether a reflected signal corresponding to the low-frequency resonant electromagnetic wave can be received; and the depth of the object to be measured is calculated based on the receiving position of the reflected signal and the initial position of the magnetic field change obtained when the detection device moves at a constant speed perpendicular to the object to be measured.

2. A method for fine geomagnetic detection, characterized in that: The steps include: Determine the object to be tested and the electromagnetic wave resonance frequency inherent to the object to be tested; The electromagnetic coil is coupled to the measuring circuit, and the electromagnetic coil is moved at a constant speed perpendicular to the object to be measured to obtain and record the real-time induced electromotive force or induced current, and the specific position of the object to be measured is determined according to the change of the induced electromotive force or induced current; After obtaining the specific position of the object to be measured, a low-frequency resonant electromagnetic wave corresponding to the inherent electromagnetic wave resonance frequency of the object to be measured is sent to the object to be measured through an electromagnetic wave transmitter, and the object to be measured is identified based on whether a reflected signal corresponding to the low-frequency resonant electromagnetic wave can be received; and the depth of the object to be measured is calculated based on the receiving position of the reflected signal and the initial position of the magnetic field change obtained when the detection device moves at a constant speed perpendicular to the object to be measured.

3. The method for fine geomagnetic detection according to claim 1, characterized in that: The detection device comprises a transverse conductor and a conductor handle arranged perpendicularly to the transverse conductor, a screw cap is arranged at one end of the transverse conductor, and a top end of the conductor handle is connected to one end of the transverse conductor through the screw cap; A capacitor box is arranged on the transverse conductor, a capacitor is arranged in the capacitor box, and an input end and an output end of the capacitor are respectively connected to the conductor handle and the transverse conductor through a wire to enhance the sensitivity of detection; The detection device is moved at a constant speed perpendicular to the direction of the object to be detected to obtain the deflection state of the two transverse conductors, and the specific position of the object to be detected is determined according to the deflection state of the two transverse conductors.

4. The method for fine geomagnetic detection according to claim 3, characterized in that: The left hand and the right hand of the human body hold a detection device respectively, so that the transverse conductors in the two detection devices are in a parallel state, and the left hand and the right hand of the human body hold a detection device respectively to form an electromagnetic induction conductor.

5. The method for fine geomagnetic detection according to claim 3, characterized in that: The human body is used as a body capacitor, and the wire arranged on the conductor handle is touched by a human hand so that the body capacitor is connected in series with the capacitor, thereby increasing the intensity of the transverse conductor in cutting the magnetic flux lines.

6. The method for fine geomagnetic detection according to claim 3, characterized in that: When the detection device is moved at a constant speed perpendicular to the direction of the object to be detected, when the object to be detected is detected, the lateral conductors located on the left hand and the right hand attract each other to form a deflection.

7. The method for fine geomagnetic detection according to claim 6, characterized in that: When the lateral conductors located in the left hand and the right hand attract each other to form a pendulum, the position of the person and the angle of the pendulum are recorded. The specific position of the object to be measured is obtained by recording the position of the person and the angle of the pendulum.

8. The method for fine geomagnetic detection according to claim 2, characterized in that: When moving, the induced electromotive force or induced current is recorded by a measuring circuit coupled to the electromagnetic coil, and the specific position of the object to be measured is determined according to the change curve of the induced electromotive force or induced current.

9. The method for fine geomagnetic detection according to claim 2 or 8, characterized in that: The measuring circuit includes at least: An amplifier circuit, composed of one or more amplifiers connected in series, coupled to the electromagnetic coil, for amplifying the electromotive force signal or current signal generated by the electromagnetic coil cutting the magnetic flux line; The measuring element is connected to the amplifier circuit and is used to measure the amplified induced electromotive force or induced current.

10. The method for fine geomagnetic detection according to claim 2 or 8, characterized in that: The specific position of the object to be measured is determined based on the peak formed by the change curve of the induced electromotive force or the induced current.

11. An application of a method for fine geomagnetic detection, characterized in that: Used to detect the location of ground fissures.

12. An application of a geomagnetic fine detection method, characterized in that: Used to detect the location of underground pipelines.

13. An application of a method for fine geomagnetic detection, characterized in that: Used to detect the location of building cracks.

14. An application of a method for fine geomagnetic detection, characterized in that: Used to detect groundwater level.

15. An application of a geomagnetic fine detection method, characterized in that: Used to detect the pile body and / or the length of the cast-in-place pile reinforcement.

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