CN111538093A - Method for shallow surface detection and transient electromagnetic instrument - Google Patents
Method for shallow surface detection and transient electromagnetic instrument Download PDFInfo
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- CN111538093A CN111538093A CN202010584049.1A CN202010584049A CN111538093A CN 111538093 A CN111538093 A CN 111538093A CN 202010584049 A CN202010584049 A CN 202010584049A CN 111538093 A CN111538093 A CN 111538093A
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- G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
- G01V3/00—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation
- G01V3/08—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation operating with magnetic or electric fields produced or modified by objects or geological structures or by detecting devices
- G01V3/10—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation operating with magnetic or electric fields produced or modified by objects or geological structures or by detecting devices using induction coils
Abstract
The invention discloses a superficial layer earth surface detection method and a transient electromagnetic instrument, belonging to the technical field of geological survey, wherein the method comprises the following steps: arranging two same coils which are oppositely connected in series, are coaxial up and down in parallel, so that the channel currents of the two same coils are in equal synchronization and have opposite current directions, and the two coils are configured into a double-coil source; placing a receiving coil on a primary field zero magnetic flux plane in the middle of the double coil sources and at a position coaxial with the double coil sources; collecting geological condition parameters and physical characteristic parameters to be surveyed, setting a transient electromagnetic profile and collecting data under the condition that the geological condition parameters and the physical characteristic parameters to be surveyed accord with the test of a transient electromagnetic method; and carrying out inversion on the acquired data to obtain the resistivity contour line sections of all the sections, analyzing the inversion result of all the transient electromagnetic detection sections, carrying out accuracy analysis operation on the inversion result, and guiding the shallow earth surface detection operation.
Description
Technical Field
The invention belongs to the technical field of geological survey, and particularly relates to a shallow earth surface detection method and a transient electromagnetic instrument.
Background
The transient electromagnetic method is also called Time domain electromagnetic method (TEM), and is a method of transmitting a primary pulse magnetic field to the ground by using an ungrounded return line or a ground line source, and observing a secondary eddy current field by using a coil or a ground electrode during the interval of the primary pulse magnetic field. In brief, the basic principle of the transient electromagnetic method is the law of electromagnetic induction. The decay process is generally divided into early, middle and late stages. The early electromagnetic field is equivalent to a high-frequency component in a frequency domain, the attenuation is fast, and the skin depth is small; the late component is equivalent to the low-frequency component in the frequency domain, the attenuation is slow, and the skin depth is large. And the earth electric characteristics of different depths can be obtained by measuring the time change rule of the secondary field of each time period after power failure.
The transient electromagnetic method early secondary field is the reaction of shallow geological information, and a self-induction electric field generated by the turn-off of the primary field and the early secondary field are overlapped to form a shallow blind area, so that the detection result cannot truly reflect the shallow stratum information. The inventor finds that the shallow blind area in the prior art is a problem which is difficult to solve in transient electromagnetic measurement, and seriously restricts the development of a transient electromagnetic method in the engineering fields of engineering investigation, disaster treatment and the like.
Disclosure of Invention
In order to solve at least the technical problems, the invention provides a method for detecting the shallow earth surface and a transient electromagnetic instrument.
According to a first aspect of the present invention, there is provided a method for shallow surface exploration, comprising:
arranging two same coils which are oppositely connected in series, are coaxial up and down in parallel, so that the channel currents of the two same coils are in equal synchronization and have opposite current directions, and the two coils are configured into a double-coil source;
placing a receiving coil on a primary field zero magnetic flux plane in the middle of the double coil sources and at a position coaxial with the double coil sources;
collecting geological condition parameters and physical characteristic parameters to be surveyed, setting a transient electromagnetic profile and collecting data under the condition that the geological condition parameters and the physical characteristic parameters to be surveyed accord with the test of a transient electromagnetic method;
and carrying out inversion on the acquired data to obtain the resistivity contour line sections of all the sections, analyzing the inversion result of all the transient electromagnetic detection sections, carrying out accuracy analysis operation on the inversion result, and guiding the shallow earth surface detection operation.
The diameter of the two same coils which are connected in series in the reverse direction, are parallel and coaxial up and down is a first preset size, and a preset distance is set between the two same coils.
The diameter of the receiving coil is set to be a second preset size, and the receiving equivalent area is a preset area.
The setting transient electromagnetic profile comprises: setting the upstream side as a zero pile number starting point, and arranging a plurality of transient electromagnetic profiles at different elevations, wherein each measuring line point is away from a preset distance.
The parameters of the data acquisition include: transmission voltage, transmission current, transmission frequency, turn-off time, superposition period.
The accuracy analysis operation is carried out on the inversion result to guide the shallow surface detection operation, and the method comprises the following steps: and performing accuracy analysis operation on the inversion result by adopting a high-density resistivity data comparison method, and taking the obtained analysis result as the guidance of shallow surface detection operation.
The accuracy analysis operation is carried out on the inversion result to guide the shallow surface detection operation, and the method comprises the following steps:
and (3) arranging a plurality of verification drill holes on the transient electromagnetic survey line by adopting a drill hole verification method, verifying the inversion result, and guiding the shallow earth surface detection operation by the obtained verification result.
According to the device, two coils with the same turns, which are parallel and coaxial up and down, are used as the transmitting source coils to obtain a zero magnetic flux surface, the receiving coil is arranged on the zero magnetic flux surface to perform data acquisition, so that the primary field can be prevented from interfering the acquisition of the early secondary field, the electromagnetic coupling can be eliminated, the receiving coil of the method cannot generate electromagnetic oscillation on the zero magnetic flux surface and is not influenced by the turn-off of the primary field, the early secondary field signal generated by the geological body eddy current response can be accurately detected, the shallow blind area of a transient electromagnetic method can be eliminated, the shallow detection accuracy is improved, and the shallow detection operation efficiency is improved.
According to a second aspect of the present invention, there is provided a transient electromagnetic instrument for shallow surface detection, comprising:
two transmitting coils, a receiving coil and a control unit;
the transmitting coil comprises two same coils which are reversely connected in series, are parallel and coaxial up and down, so that the channel currents of the two same coils are in equal synchronization and have opposite current directions, and the two coils are configured into a double-coil source;
the receiving coil is arranged on a primary field zero magnetic flux plane right in the middle of the double coil sources and is coaxial with the double coil sources;
the control part is used for collecting geological condition parameters to be surveyed and physical characteristic parameters, and setting a transient electromagnetic profile for data collection under the condition that the geological condition parameters to be surveyed and the physical characteristic parameters accord with the test of a transient electromagnetic method;
and carrying out inversion on the acquired data to obtain the resistivity contour line sections of all the sections, analyzing the inversion result of all the transient electromagnetic detection sections, carrying out accuracy analysis operation on the inversion result, and guiding the shallow earth surface detection operation.
According to a third aspect of the invention, there is provided a computer device comprising a memory, a processor and a computer program stored on the memory and executable on the processor,
the processor, when executing the program, performs the steps of the method as in any one of the above.
According to a fourth aspect of the present invention, there is provided a computer readable storage medium storing a program which, when executed, is capable of implementing a method as defined in any one of the above.
The invention has the beneficial effects that: the device adopts two coils with the same number of turns, which are parallel and coaxial up and down, which are electrified by reverse current as the transmitting source coil to obtain a zero magnetic flux surface, and arranges the receiving coil on the zero magnetic flux surface for data acquisition, thereby avoiding the interference of a primary field on the acquisition of an early secondary field and eliminating electromagnetic coupling.
Drawings
The above and/or additional aspects and advantages of the present invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which,
fig. 1 is a flowchart of a method for detecting a shallow surface according to the present invention.
Detailed Description
Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the drawings are illustrative only and should not be construed as limiting the invention.
In order to more clearly illustrate the invention, the invention is further described below with reference to preferred embodiments and the accompanying drawings. Similar parts in the figures are denoted by the same reference numerals. It is to be understood by persons skilled in the art that the following detailed description is illustrative and not restrictive, and is not to be taken as limiting the scope of the invention.
In a first aspect of the present invention, there is provided a method for shallow surface exploration, as shown in fig. 1, comprising:
step 101: arranging two same coils which are oppositely connected in series, are coaxial up and down in parallel, so that the channel currents of the two same coils are in equal synchronization and have opposite current directions, and the two coils are configured into a double-coil source;
in the embodiment of the invention, the diameters of the two same coils which are connected in series in the opposite direction, are parallel and coaxial up and down are a first preset size, and a preset distance is set between the two same coils. Wherein the first preset size is 0.6 m, and the preset spacing is 0.4 m.
Step 102: placing a receiving coil on a primary field zero magnetic flux plane in the middle of the double coil sources and at a position coaxial with the double coil sources;
in the embodiment of the present invention, the diameter of the receiving coil is set to be a second predetermined size, and the receiving equivalent area is a predetermined area. The second predetermined size may be 0.5 meter, and the predetermined area is 200 square meters.
Step 103: collecting geological condition parameters and physical characteristic parameters to be surveyed, setting a transient electromagnetic profile and collecting data under the condition that the geological condition parameters and the physical characteristic parameters to be surveyed accord with the test of a transient electromagnetic method;
in the embodiment of the invention, geological condition parameters to be surveyed and physical characteristic parameters are collected, the geophysical precondition with transient electromagnetic test is judged under the condition that the resistivity difference between the collected unfavorable geology and the complete geology is obvious, the upstream side can be set as a zero pile number starting point, a plurality of transient electromagnetic profiles are arranged at different elevations, and each measuring line point is away from a preset distance which can be 5 meters.
Further, the parameters of the data acquisition include: transmission voltage, transmission current, transmission frequency, turn-off time, superposition period. Wherein, the sending voltage can be 12 volts, and the sending current can be 10 amperes; the transmission frequency may be 50 hz, the off-time may be 0.04 ms, and the overlap period may be 1000 times.
Step 104: and carrying out inversion on the acquired data to obtain the resistivity contour line sections of all the sections, analyzing the inversion result of all the transient electromagnetic detection sections, carrying out accuracy analysis operation on the inversion result, and guiding the shallow earth surface detection operation.
In an embodiment of the present invention, the performing accuracy analysis operation on the inversion result to guide shallow surface exploration includes: and performing accuracy analysis operation on the inversion result by adopting a high-density resistivity data comparison method, and taking the obtained analysis result as the guidance of shallow surface detection operation.
In another embodiment of the present invention, the performing an accuracy analysis operation on the inversion result to guide a shallow surface exploration operation includes: and (3) arranging a plurality of verification drill holes on the transient electromagnetic survey line by adopting a drill hole verification method, verifying the inversion result, and guiding the shallow earth surface detection operation by the obtained verification result.
In another embodiment of the present invention, there is provided a method for shallow surface exploration, including:
two identical coils with a diameter of 0.6 meter are used as transmitting coils, the two transmitting coils are arranged in the direction of the annular surface, are parallel up and down, have a distance of 0.4 meter, are coaxially connected in series, have opposite current directions, and are configured into a double-coil source.
A receiving coil with a diameter of 0.5 meter is placed on a primary field zero-flux plane in the middle of the double coil sources and is coaxial with the double coil sources, wherein the receiving equivalent area is 200 square meters.
In the embodiment of the invention, the transmission voltage is 12 volts, and the transmission current is 10 amperes; the transmission frequency is 50 Hz, the off-time is 0.04 ms, and the superposition period is 1000 times.
In the embodiment, a zero magnetic flux surface is obtained by adopting a device which is provided with two coils with the same number of turns and coaxial in an up-down parallel mode and is electrified with reverse current as a transmitting source coil, a receiving coil is arranged on the zero magnetic flux surface for data acquisition, the primary field can be prevented from interfering the acquisition of the early secondary field, the electromagnetic coupling can be eliminated, the receiving coil of the method can not generate electromagnetic oscillation on the zero magnetic flux surface and is not influenced by the turn-off of the primary field, the early secondary field signal generated by the geological body eddy current response can be accurately detected, the shallow blind area of a transient electromagnetic method can be eliminated, the shallow detection accuracy is improved, and the shallow detection operation efficiency is improved.
In this embodiment, the primary field is a vector superposition of the primary fields of the two transmitting coils, the current loop replaces the circular coil, and the magnetic field calculation process includes: establishing a column coordinate (unit vectors are respectively u: u) by taking the center of a horizontal current loop (radius a, current I) as an originρ，uθ，uz) Let r, r' be the field points P (ρ, θ, z) andthe position vector of the source point P '(ρ', θ ', z').
In free total space, the vector potential A generated by a finite-area DC source is (Nabighian and Macnae, 1991)
A(r)＝∫vJ(r′)G(r，r′)dV′，
Wherein J (r ') is a current density vector, G (r, r ') is a free space Green's function, and the method specifically comprises the following steps: the current density vector J according to the horizontal current loop is independent of θ', with only a tangential component JθI.e. by
J＝Jθuθ＝I(ρ′-a)(z′)uθ.
Free space green's function:
this gives:
wherein the content of the first and second substances,
k (q), E (q) are full elliptic integrals of the first and second types, respectively.
Then according to
Where μ 0 is the permeability of free space, Δ × a represents the rotation of vector a, in a cylindrical coordinate system
Obtaining each component of the magnetic field generated by the current loop
And calculating the primary magnetic field of the double coil sources according to the formula and the vector superposition principle, wherein the magnetic force line of the middle plane of the double coil sources is horizontal and is a zero magnetic flux plane of the primary field, and the plane receives the pure secondary field response under the ground without being influenced by the turn-off of the primary field.
And (3) analyzing the transient secondary field excited by the double-coil source in the uniform half-space underground, and presenting the energy concentration advantage of the underground central coupling field. The ungrounded coil source can be equivalent to a magnetic source, the electric field of the underground uniform half space is obtained according to the vector potential of the magnetic source, the electric field is firstly analyzed in a frequency domain, and then the electric field is converted into a time domain through inverse Laplace transformation.
Let horizontal current loop (radius a, transmit harmonic current Ie)iωt) The position h above the earth surface is located, the projection of the current ring on the earth surface is used as an origin O, the vertical direction is positive, a cylindrical coordinate system is established, and the uniform half space is simplified into a two-layer model: the upper layer is air, and the conductivity sigma 0 is approximately equal to 0; the lower layer is a uniform stratum with conductivity sigma 1. The magnetic vector potential generated by the horizontal current loop has only a vertical component and is independent of theta, and is respectively defined as F above the ground and below the ground0＝F0(ρ，z)uz，F1＝F1(ρ，z)uz，F0、F1Is a corresponding scalar potential.
Under quasi-static conditions, the scalar potential at a point (ρ, θ, z) in the upper semi-air layer directly references the Nabighian (1992) derivation:
wherein the content of the first and second substances,
J0、J1respectively a zero order Bessel function and a first order Bessel function,
the subsurface layer being a passive bottom layer, with scalar potential F1Satisfy the requirement of
When the earth's surface (z is 0), the boundary condition B is satisfiedz0＝Bz1，Hρ0＝Hρ1. If the permeability of the above-ground space and the underground space are assumed to be mu0Then there is H0＝H1Thus F0＝F1。
In combination with the boundary conditions, reference to Nabighian (1992) is derived
Then according to
Obtaining only tangential components of the electric field below the earth's surface
By inverse Laplace conversion to the time domain, a step-waveform current-excited subsurface transient field can be obtained
Wherein the content of the first and second substances,
to facilitate the calculation, get
Then can obtain
Further, assume that
When sigma is1T, H, R, Z are constants which fit into any geophysical observation range and are calculated to obtain y1、y2The oscillation decays to infinity close to 0 above and below 0 as x increases.
An infinite integration interval [0, ∞) can therefore be approximated as a finite integration interval [0, m ] and converted into a discrete numerical integration:
theoretically, when the discrete numerical integration is calculated in matlab, the larger the integration upper limit m is, the smaller the integration step Δ x is, and the closer the integration value is to the true value, the actual calculation shows that when m is 2, Δ x is 0.01, the accuracy requirement can be met. First, calculate out*Then according to the formula jθ＝σ1 θ＝I*/a2And (5) obtaining the underground current density.
Although the energy is relatively weakened when the method provided by the invention is compared with the single coil source of the traditional transient electromagnetic method, the energy of the underground central coupling field right below the single coil source is more concentrated, the side influence range is reduced, and the transverse resolution of shallow layer abnormity can be improved.
The method comprises the steps that under the condition of geological exploration, geological condition parameters to be surveyed and physical characteristic parameters can be collected, and under the condition that the geological condition parameters to be surveyed and the physical characteristic parameters accord with the test of a transient electromagnetic method, a transient electromagnetic profile is set for data collection;
in the embodiment of the invention, the geological condition parameters to be surveyed and the physical characteristic parameters are collected, and the geophysical precondition with transient electromagnetic test is judged under the condition that the collected unfavorable geology such as karst, erosion crack, broken rock mass and the like has obvious resistivity difference with the complete geology such as the complete rock mass. For example, the broken cover layer of the highway side is mainly the fourth series slope residual and ice water accumulated gravels soil, the mud content is high, the resistivity is between 50 and 800 omega.m, and the resistivity of the complete bedrock is more than 1500 omega.m. Obvious resistivity difference exists between unfavorable geological rock masses such as karst, corrosion crack and broken rock mass and complete rock mass, and the geophysical precondition for transient electromagnetic method testing is provided.
In this embodiment, the upstream side may be set as a zero pile number starting point, a plurality of transient electromagnetic profiles are arranged at different elevations, and each survey line point is a preset distance from the preset distance, where the preset distance may be 5 meters. Specifically, an upstream side is taken as a zero pile number starting point, four transient electromagnetic sections are distributed at different elevations, and the sections are respectively a section one: 270 m, section two: 210 m, section three: 255 m, section four: 360 meters, and the distance between each line measuring point and each line measuring point is 5 meters.
And carrying out inversion on the acquired data to obtain the resistivity contour line sections of all the sections, analyzing the inversion result of all the transient electromagnetic detection sections, carrying out accuracy analysis operation on the inversion result, and guiding the shallow earth surface detection operation.
In an embodiment of the present invention, the performing accuracy analysis operation on the inversion result to guide shallow surface exploration includes: and performing accuracy analysis operation on the inversion result by adopting a high-density resistivity data comparison method, and taking the obtained analysis result as the guidance of shallow surface detection operation.
In another embodiment of the present invention, the performing an accuracy analysis operation on the inversion result to guide a shallow surface exploration operation includes: and (3) arranging a plurality of verification drill holes on the transient electromagnetic survey line by adopting a drill hole verification method, verifying the inversion result, and guiding the shallow earth surface detection operation by the obtained verification result.
According to a second aspect of the present invention, there is provided a transient electromagnetic instrument for shallow surface detection, comprising:
two transmitting coils, a receiving coil and a control unit;
the sending coil comprises two same coils which are reversely connected in series, are parallel and coaxial up and down, so that the currents of the two same coils are in equal synchronization and opposite in direction, and the two coils are configured into a double-coil source;
in the embodiment of the invention, the diameters of the two same coils which are connected in series in the opposite direction, are parallel and coaxial up and down are a first preset size, and a preset distance is set between the two same coils. Wherein the first preset size is 0.6 m, and the preset spacing is 0.4 m.
The receiving coil is arranged on a primary field zero magnetic flux plane right in the middle of the double coil sources and is coaxial with the double coil sources;
in the embodiment of the present invention, the diameter of the receiving coil is set to be a second predetermined size, and the receiving equivalent area is a predetermined area. The second predetermined size may be 0.5 meter, and the predetermined area is 200 square meters.
The control part is used for collecting geological condition parameters to be surveyed and physical characteristic parameters, and setting a transient electromagnetic profile for data collection under the condition that the geological condition parameters to be surveyed and the physical characteristic parameters accord with the test of a transient electromagnetic method;
and the method is also used for inverting the acquired data to obtain the resistivity contour line sections of all the sections, analyzing the inversion result of all the transient electromagnetic detection sections, and carrying out accuracy analysis operation on the inversion result to guide the shallow earth surface detection operation.
In the embodiment of the invention, geological condition parameters to be surveyed and physical characteristic parameters are collected, the geophysical precondition with transient electromagnetic test is judged under the condition that the resistivity difference between the collected unfavorable geology and the complete geology is obvious, the upstream side can be set as a zero pile number starting point, a plurality of transient electromagnetic profiles are arranged at different elevations, and each measuring line point is away from a preset distance which can be 5 meters.
Further, the parameters of the data acquisition include: transmission voltage, transmission current, transmission frequency, turn-off time, superposition period. Wherein, the sending voltage can be 12 volts, and the sending current can be 10 amperes; the transmission frequency may be 50 hz, the off-time may be 0.04 ms, and the overlap period may be 1000 times.
In an embodiment of the present invention, the performing an accuracy analysis operation on the inversion result to guide a shallow surface exploration operation specifically includes: and performing accuracy analysis operation on the inversion result by adopting a high-density resistivity data comparison method, and taking the obtained analysis result as the guidance of shallow surface detection operation.
In another embodiment of the present invention, the performing an accuracy analysis operation on the inversion result to guide a shallow surface exploration operation includes: and (3) arranging a plurality of verification drill holes on the transient electromagnetic survey line by adopting a drill hole verification method, verifying the inversion result, and guiding the shallow earth surface detection operation by the obtained verification result.
According to a third aspect of the present invention, there is provided a computer device comprising a memory, a processor and a computer program stored on the memory and executable on the processor, the processor implementing the steps of the method when executing the program, comprising:
arranging two same coils which are oppositely connected in series, are coaxial up and down in parallel, so that the channel currents of the two same coils are in equal synchronization and have opposite current directions, and the two coils are configured into a double-coil source;
placing a receiving coil on a primary field zero magnetic flux plane in the middle of the double coil sources and at a position coaxial with the double coil sources;
collecting geological condition parameters and physical characteristic parameters to be surveyed, setting a transient electromagnetic profile and collecting data under the condition that the geological condition parameters and the physical characteristic parameters to be surveyed accord with the test of a transient electromagnetic method;
and carrying out inversion on the acquired data to obtain the resistivity contour line sections of all the sections, analyzing the inversion result of all the transient electromagnetic detection sections, carrying out accuracy analysis operation on the inversion result, and guiding the shallow earth surface detection operation.
The diameter of the two same coils which are connected in series in the reverse direction, are parallel and coaxial up and down is a first preset size, and a preset distance is set between the two same coils.
The diameter of the receiving coil is set to be a second preset size, and the receiving equivalent area is a preset area.
The setting transient electromagnetic profile comprises: setting the upstream side as a zero pile number starting point, and arranging a plurality of transient electromagnetic profiles at different elevations, wherein each measuring line point is away from a preset distance.
The parameters of the data acquisition include: transmission voltage, transmission current, transmission frequency, turn-off time, superposition period.
The accuracy analysis operation is carried out on the inversion result to guide the shallow surface detection operation, and the method comprises the following steps: and performing accuracy analysis operation on the inversion result by adopting a high-density resistivity data comparison method, and taking the obtained analysis result as the guidance of shallow surface detection operation.
The accuracy analysis operation is carried out on the inversion result to guide the shallow surface detection operation, and the method comprises the following steps:
and (3) arranging a plurality of verification drill holes on the transient electromagnetic survey line by adopting a drill hole verification method, verifying the inversion result, and guiding the shallow earth surface detection operation by the obtained verification result.
According to a fourth aspect of the present invention, there is provided a computer readable storage medium storing a program which, when executed, is capable of implementing the method as described above.
As used herein, the singular forms "a", "an", "the" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and/or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. It will be understood that when an element is referred to as being "connected" or "coupled" to another element, it can be directly connected or coupled to the other element or intervening elements may also be present. Further, "connected" or "coupled" as used herein may include wirelessly connected or wirelessly coupled. As used herein, the term "and/or" includes all or any element and all combinations of one or more of the associated listed items.
It will be understood by those skilled in the art that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the prior art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.
It should be understood that the above detailed description of the technical solution of the present invention with the help of preferred embodiments is illustrative and not restrictive. On the basis of reading the description of the invention, a person skilled in the art can modify the technical solutions described in the embodiments, or make equivalent substitutions for some technical features; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.
Claims (10)
1. A method for shallow surface exploration, comprising:
arranging two same coils which are oppositely connected in series, are coaxial up and down in parallel, so that the channel currents of the two same coils are in equal synchronization and have opposite current directions, and the two coils are configured into a double-coil source;
placing a receiving coil on a primary field zero magnetic flux plane in the middle of the double coil sources and at a position coaxial with the double coil sources;
collecting geological condition parameters and physical characteristic parameters to be surveyed, setting a transient electromagnetic profile and collecting data under the condition that the geological condition parameters and the physical characteristic parameters to be surveyed accord with the test of a transient electromagnetic method;
and carrying out inversion on the acquired data to obtain the resistivity contour line sections of all the sections, analyzing the inversion result of all the transient electromagnetic detection sections, carrying out accuracy analysis operation on the inversion result, and guiding the shallow earth surface detection operation.
2. The method of claim 1,
the diameter of the two same coils which are connected in series in the reverse direction, are parallel and coaxial up and down is a first preset size, and a preset distance is set between the two same coils.
3. The method of claim 1,
the diameter of the receiving coil is set to be a second preset size, and the receiving equivalent area is a preset area.
4. The method of claim 1,
the setting transient electromagnetic profile comprises: setting the upstream side as a zero pile number starting point, and arranging a plurality of transient electromagnetic profiles at different elevations, wherein each measuring line point is away from a preset distance.
5. The method of claim 1,
the parameters of the data acquisition include: transmission voltage, transmission current, transmission frequency, turn-off time, superposition period.
6. The method of claim 1,
the accuracy analysis operation is carried out on the inversion result to guide the shallow surface detection operation, and the method comprises the following steps: and performing accuracy analysis operation on the inversion result by adopting a high-density resistivity data comparison method, and taking the obtained analysis result as the guidance of shallow surface detection operation.
7. The method of claim 1,
the accuracy analysis operation is carried out on the inversion result to guide the shallow surface detection operation, and the method comprises the following steps:
and (3) arranging a plurality of verification drill holes on the transient electromagnetic survey line by adopting a drill hole verification method, verifying the inversion result, and guiding the shallow earth surface detection operation by the obtained verification result.
8. A transient electromagnetic instrument for shallow surface detection, comprising:
two transmitting coils, a receiving coil and a control unit;
the transmitting coil comprises two same coils which are reversely connected in series, are parallel and coaxial up and down, so that the channel currents of the two same coils are in equal synchronization and have opposite current directions, and the two coils are configured into a double-coil source;
the receiving coil is arranged on a primary field zero magnetic flux plane right in the middle of the double coil sources and is coaxial with the double coil sources;
the control part is used for collecting geological condition parameters to be surveyed and physical characteristic parameters, and setting a transient electromagnetic profile for data collection under the condition that the geological condition parameters to be surveyed and the physical characteristic parameters accord with the test of a transient electromagnetic method;
and carrying out inversion on the acquired data to obtain the resistivity contour line sections of all the sections, analyzing the inversion result of all the transient electromagnetic detection sections, carrying out accuracy analysis operation on the inversion result, and guiding the shallow earth surface detection operation.
9. A computer device comprising a memory, a processor, and a computer program stored on the memory and executable on the processor,
the processor, when executing the program, performs the steps of the method of any one of claims 1 to 7.
10. A computer-readable storage medium, characterized in that the computer-readable storage medium stores a program which, when executed, is capable of implementing the method according to any one of claims 1-7.
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111929745A (en) * | 2020-08-24 | 2020-11-13 | 北京中核大地矿业勘查开发有限公司 | Comprehensive underground water resource exploration system and exploration method thereof |
| CN112817057A (en) * | 2020-12-31 | 2021-05-18 | 中国地质调查局天津地质调查中心 | Method for economically, quickly and accurately detecting underground space distribution characteristics of landfill pond |
| CN114089424A (en) * | 2021-11-02 | 2022-02-25 | 武汉船舶通信研究所（中国船舶重工集团公司第七二二研究所） | Portable shallow transient electromagnetic detection device |
| CN115629421A (en) * | 2022-12-19 | 2023-01-20 | 吉林大学 | Double-fold-line-source magnetic resonance potential water-induced landslide detection method and three-dimensional forward modeling method |
| CN115629421B (en) * | 2022-12-19 | 2023-03-10 | 吉林大学 | Double-fold-line-source magnetic resonance potential water-induced landslide detection method and three-dimensional forward modeling method |
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