CN118091772B - Polluted site partition interpretation method and system based on time domain induced polarization - Google Patents
Polluted site partition interpretation method and system based on time domain induced polarization Download PDFInfo
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Abstract
The present disclosure provides a method and a system for analyzing a polluted site partition based on time domain induced polarization, which relates to the technical field of pollution type monitoring and classification, and comprises the steps of converting all attenuation curves in full waveform data to obtain a real part apparent conductivity spectrum curve and an imaginary part apparent conductivity spectrum curve; calculating the conductivity representative value of the real part visual conductivity spectrum curve in the low frequency band and the conductivity representative value of the imaginary part visual conductivity spectrum curve in the three frequency bands; inverting the obtained conductivity representative value to obtain a real part conductivity representative value section under low frequency and an imaginary part conductivity representative value section under each frequency band; calculating a judgment value between each frequency band of the representative value of the imaginary conductivity according to the field pollution type and concentration and the physical relationship between the real part conductivity and the imaginary part conductivity, and dividing the pollution area into different characteristic types according to the judgment standard; and determining the pollutant types corresponding to the different characteristic types to realize the partitioning of the polluted area.
Description
Technical Field
The disclosure relates to the technical field of pollution type monitoring and classification, in particular to a method and a system for analyzing a polluted site partition based on time domain induced polarization.
Background
The statements in this section merely provide background information related to the present disclosure and may not necessarily constitute prior art.
At present, the repair work of soil and groundwater pollution is increasingly paid attention to. The investigation work of the polluted site is a premise and a foundation for efficient and accurate repair, and the monitoring of the repair process and the evaluation of the repair effect play an important guiding role for smooth completion of the repair work. Investigation, repair monitoring and repair effect evaluation of contaminated sites put higher demands on accurate characterization of contaminated areas and contaminated concentrations. In recent years, geophysical methods represented by an electric method are gradually applied to the polluted site depiction, wherein an induced polarization method is used as extension and expansion of a resistivity method, and the parameter information is rapidly developed. However, the induced polarization method still has uncertainty, and the factors such as water content, porosity, particle size and the like of the underground medium can cause the change of induced polarization parameters, so that the accuracy of an interpretation result of the induced polarization is limited; in addition, response characteristics of induced polarization parameters caused by the same pollution types (organic pollution, heavy metal pollution and inorganic salt pollution) are the same, and different subclasses of the same pollution type cannot be distinguished only by using the induced polarization parameters, so that the repair work is limited. Therefore, a finer interpretation classification method is needed to further interpret the information contained in the induced polarization, refine the pollution classification, and further realize effective division of the polluted site, so as to provide richer guiding information for repair.
However, the lag of the research of the time domain induced polarization characterization partition interpretation method of the polluted site is mainly due to the fact that full waveform data obtained by the induced polarization cannot be fully and effectively utilized. Current methods of using full waveform induced polarization data are to perform full time domain inversion. According to the method, a large amount of original data are integrated into window data, and abundant frequency spectrum information in induced polarization data is lost in the integration process, so that effective information is lost. In addition, the inversion result obtained according to the method reflects the result of the overall induced polarization parameter, and the difference of parameters in different frequency bands is not considered. The method can remove attenuation information in a short time after power failure, so that high-frequency information is lost. Because of similar induced polarization response characteristics of the same type of contaminated medium, the current induced polarization interpretation method has limited information, and the traditional partition interpretation method cannot distinguish different subclasses of the same type of contamination.
Disclosure of Invention
In order to solve the problems, the method and the system for analyzing the polluted site partition based on the time domain induced polarization are provided, full waveform data acquired by the polluted site induced polarization are synthesized, the frequency spectrum information rich in the induced polarization is considered, data processing and inversion methods of different frequency bands are established, physical relations between the parameter characteristics of each frequency band and the pollution concentration are established respectively, the parameter information quantity for judging the characteristics of pollutants is increased, and different subclasses of the same pollution type can be effectively distinguished.
According to some embodiments, the present disclosure employs the following technical solutions:
a method for zoned interpretation of contaminated sites based on time domain induced polarization, comprising:
Acquiring full waveform data of induced polarization of a contaminated site, and converting all attenuation curves in the full waveform data to obtain a real part apparent conductivity spectrum curve and an imaginary part apparent conductivity spectrum curve;
calculating a real part apparent conductivity representative value under a low frequency band of the real part apparent conductivity spectrum curve, and calculating imaginary part apparent conductivity representative values under high, medium and low frequency bands of the imaginary part apparent conductivity spectrum curve;
inverting the virtual visual conductivity representative value of each frequency band and the real visual conductivity representative value of the low-frequency band to obtain a real conductivity representative value section of the low-frequency band and an imaginary conductivity representative value section of each frequency band;
Extracting pixel information of all grids of each frequency band in a pollution area in a section of the imaginary part conductivity representative value according to the field pollution type, concentration and physical relation between the real part conductivity and the imaginary part conductivity; calculating a judgment value between each frequency band of the imaginary part conductivity representative value in each grid, and dividing the pollution area into different characteristic types according to a judgment standard;
and determining the pollutant types corresponding to the different characteristic types to realize the partitioning of the polluted area.
According to some embodiments, the present disclosure employs the following technical solutions:
A contaminated site zoned interpretation system based on time domain induced polarization, comprising:
the data acquisition module is used for acquiring full waveform data of induced polarization of the polluted site, and converting all attenuation curves in the full waveform data to obtain a real part apparent conductivity spectrum curve and an imaginary part apparent conductivity spectrum curve;
The data calculation module is used for calculating the real part apparent conductivity representative value under the low frequency band of the real part apparent conductivity spectrum curve and calculating the imaginary part apparent conductivity representative values under the high, medium and low frequency bands of the imaginary part apparent conductivity spectrum curve;
inverting the virtual visual conductivity representative value of each frequency band and the real visual conductivity representative value of the low-frequency band to obtain a real conductivity representative value section of the low-frequency band and an imaginary conductivity representative value section of each frequency band;
The data interpretation module is used for extracting pixel information of all grids of each frequency band in the pollution area in the section of the representative value of the imaginary conductivity according to the field pollution type and concentration and the physical relationship between the real part and the imaginary part conductivity; calculating a judgment value between each frequency band of the imaginary part conductivity representative value in each grid, and dividing the pollution area into different characteristic types according to a judgment standard; and determining the pollutant types corresponding to the different characteristic types to realize the partitioning of the polluted area.
According to some embodiments, the present disclosure employs the following technical solutions:
A non-transitory computer readable storage medium for storing computer instructions which, when executed by a processor, implement the contaminated site partition interpretation method based on time domain induced polarization.
According to some embodiments, the present disclosure employs the following technical solutions:
An electronic device, comprising: a processor, a memory, and a computer program; wherein the processor is coupled to the memory and the computer program is stored in the memory, the processor executing the computer program stored in the memory when the electronic device is operating, to cause the electronic device to perform the contaminated site partition interpretation method implementing the time domain induced polarization based method.
Compared with the prior art, the beneficial effects of the present disclosure are:
According to the time domain induced polarization-based contaminated site zonal interpretation method, the induced polarization full waveform data acquired in the contaminated site investigation are synthesized, all attenuation curves in the full waveform data are converted, a real part apparent conductivity spectrum curve and an imaginary part apparent conductivity spectrum curve are obtained, rich waveform information is fully utilized, the information quantity of the contaminated site depiction is increased, and the accuracy of the induced polarization interpretation result is improved.
According to the time domain induced polarization-based contaminated site zonal interpretation method, the real part visual conductivity representative value under the low frequency band of the real part visual conductivity spectrum curve is calculated by dividing the high frequency, medium frequency and low frequency information, the imaginary part visual conductivity representative value under the high, medium and low frequency bands of the imaginary part visual conductivity spectrum curve is calculated, the difference of the parameters of different frequency bands is integrated, and the physical relationship between the characteristic parameters of each frequency band and the pollution concentration can be reflected.
According to the time domain induced polarization-based contaminated site partition interpretation method, the contaminated area is divided into different characteristic types according to the site contamination type, the concentration and the physical relationship between the contaminated area and the conductivity of the real part and the imaginary part and according to the judgment standard, different subclasses of the same contaminated type can be effectively distinguished, the uncertainty of the induced polarization limited parameters is reduced, and sufficient guiding information can be provided for subsequent repair work.
The time domain induced polarization-based polluted site partition interpretation method can be independently used for all types of attenuation curves, does not need to fit an induced polarization empirical model, can be rapidly completed in field work, and improves field work efficiency.
Drawings
The accompanying drawings, which are included to provide a further understanding of the disclosure, illustrate and explain the exemplary embodiments of the disclosure and together with the description serve to explain the disclosure, and do not constitute an undue limitation on the disclosure.
FIG. 1 is a flowchart of a method performed by a contaminated site zonal interpretation system based on time domain induced polarization in accordance with an embodiment of the present disclosure;
FIG. 2 is a schematic diagram of full waveform induced polarization time-frequency conversion according to an embodiment of the present disclosure;
FIG. 3 is a schematic diagram of partition of induced polarization spectral data according to an embodiment of the present disclosure;
FIG. 4 is a graph showing the physical relationship between the contamination concentration and the induced polarization parameter according to the embodiment of the present disclosure;
FIG. 5 is a schematic illustration of a contaminated site induced polarization profile division in accordance with an embodiment of the present disclosure;
FIG. 6 is a schematic diagram of a partition interpretation feature type decision criterion of an embodiment of the present disclosure;
FIG. 7 is a schematic view of contaminated zone zonal interpretation of an embodiment of the present disclosure.
Detailed Description
The disclosure is further described below with reference to the drawings and examples.
It should be noted that the following detailed description is illustrative and is intended to provide further explanation of the present disclosure. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs.
It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of exemplary embodiments in accordance with the present disclosure. As used herein, the singular is also intended to include the plural unless the context clearly indicates otherwise, and furthermore, it is to be understood that the terms "comprises" and/or "comprising" when used in this specification are taken to specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof.
Example 1
According to the method, full waveform data acquired by the induced polarization of the polluted site is integrated, frequency spectrum information rich in the induced polarization is considered, data processing and inversion methods of different frequency bands are established, the induced polarization results are interpreted according to frequency band characteristic regions, waveform information of the induced polarization data is fully utilized, the differences of parameters in different frequency bands are integrated through the division of high-frequency, medium-frequency and low-frequency information, physical relations between the parameter characteristics of each frequency band and the pollution concentration are established, the parameter information quantity for judging the characteristics of pollutants is increased, different classes of the same pollution type can be effectively distinguished, the describing precision of the polluted site is greatly improved, the uncertainty of the limited parameter information of the induced polarization is reduced, and sufficient guiding information is provided for efficient and accurate completion of the follow-up polluted site repairing work, and the method comprises the following steps:
step one: acquiring full waveform data of induced polarization of a contaminated site, and converting all attenuation curves in the full waveform data to obtain a real part apparent conductivity spectrum curve and an imaginary part apparent conductivity spectrum curve;
Step two: calculating a real part apparent conductivity representative value under a low frequency band of the real part apparent conductivity spectrum curve, and calculating imaginary part apparent conductivity representative values under high, medium and low frequency bands of the imaginary part apparent conductivity spectrum curve;
Step three: inverting the virtual visual conductivity representative value of each frequency band and the real visual conductivity representative value of the low-frequency band to obtain a real conductivity representative value section of the low-frequency band and an imaginary conductivity representative value section of each frequency band;
Step four: extracting pixel information of all grids of each frequency band in a pollution area in a section of the imaginary part conductivity representative value according to the field pollution type, concentration and physical relation between the real part conductivity and the imaginary part conductivity; calculating a judgment value between each frequency band of the imaginary part conductivity representative value in each grid, and dividing the pollution area into different characteristic types according to a judgment standard;
Step five: and determining the pollutant types corresponding to the different characteristic types to realize the partitioning of the polluted area.
As an embodiment, the implementation process of the method for interpreting the contaminated site partition based on time domain induced polarization of the present disclosure includes:
step 1: acquiring an induced polarization section of a polluted site, acquiring induced polarization full-waveform data of all data points, converting all attenuation curve time domain data of the full-waveform data into amplitude and phase data of a frequency domain by using a time-frequency conversion method, and obtaining a real part apparent conductivity spectrum curve and an imaginary part apparent conductivity spectrum curve according to the following formula:
In the method, in the process of the invention, For the real part of the apparent conductivity,For the imaginary part to look at the electrical conductivity,For the amplitude value after the time-frequency transformation,Is the phase after time-frequency conversion.
Further, the time-frequency transformation method may be a wavelet transformation, fourier transformation or hilbert-yellow transformation method.
Step 2: the frequency bands of the obtained real part visual conductivity spectrum curve and the imaginary part visual conductivity spectrum curve are divided into three frequency bands of high frequency, intermediate frequency and low frequency, and the division standards of the high frequency, the intermediate frequency and the low frequency are as follows:
1) When the time for measurement is 8 seconds or more, the three frequency bands are high frequency (10-100 Hz), medium frequency (1-10 Hz) and low frequency (0.1-1 Hz);
2) When the time for measurement is 1-8 seconds, the three frequency bands are high frequency (20-100 Hz), medium frequency (5-20 Hz) and low frequency (1-5 Hz).
According to the divided frequency bands, further calculating a real part apparent conductivity representative value under a low frequency band of the real part apparent conductivity spectrum curve, and calculating imaginary part apparent conductivity representative values under high, medium and low frequency bands of the imaginary part apparent conductivity spectrum curve, wherein the imaginary part apparent conductivity representative value of each frequency band is determined by the following formula:
In the method, in the process of the invention, 、、The high frequency, the medium frequency and the low frequency are respectively the imaginary parts which look at the conductivity representative values,For the number of data points in each frequency band,For the first frequency bandThe frequency of the data points is such that,For the first frequency bandThe imaginary part of the data point is the conductivity.
Further, the representative value of the real part apparent conductivity in the low frequency band is an arithmetic average value of all the real part apparent conductivities in the low frequency band.
Step 3: inverting the virtual visual conductivity representative value of each frequency band and the real visual conductivity representative value of the low-frequency band to obtain a real conductivity representative value profile of the low-frequency band and the virtual conductivity representative value profile distribution of each frequency band.
During inversion, the coverage of grids is evaluated, grids which do not reach the coverage threshold are not considered in interpretation, the coverage value of each grid is the sum of absolute sensitivity values of all data points normalized according to the cell size, and the coverage value is determined by the following formula:
In the above-mentioned method, the step of, As a result of the unknown parameters,Is a forward model; for the real part conductivity,,For the conductivity of the imaginary part,,. Model parametersAnd the sum is the model coverage rate of parameter distribution, and a coverage threshold value is comprehensively determined according to the depth and the resolution required by the interpretation result.
Step 4: for inversion results of a pollution site, physical property relations between pollution concentration and low-frequency real part and three-frequency band imaginary part conductivities are established, and for an organic pollution area, the relations between the pollution concentration and the real part conductivities are established as follows:
for heavy metal pollution areas, the relationship between the pollution concentration and the conductivities of the real part and the imaginary part is established as follows:
for the inorganic salt pollution area, the relation between the pollution concentration and the electric conductivity of the real part and the imaginary part is established as follows:
In the above-mentioned method, the step of, For the real part of the electrical conductivity,For the conductivity of the imaginary part,In order to achieve a concentration of the contaminants,And determining the physical property relation of each frequency band according to the field corresponding relation or laboratory samples for parameters to be estimated.
And (3) according to the established physical relationship and a pollution concentration threshold, combining a pollution restoration target value, and delineating a characteristic pollution area:
In the above-mentioned method, the step of, In order to be able to finally contaminate the area,For contaminated areas delineated by high frequencies,For a contaminated area delineated by the intermediate frequency,A contaminated area delineated for low frequencies. And finally, the pollution area represents the total concentration area of organic pollution, heavy metal pollution or inorganic salt pollution, all areas with total concentration exceeding the standard are divided according to grid pixels, and the information of the areas without exceeding the standard is deleted.
Calculating a judgment value between high frequency and medium frequency and a judgment value between medium frequency and low frequency of the conductivity of the imaginary part of each grid in the final pollution area, wherein the judgment value is calculated according to the following formula:
In the above-mentioned method, the step of, Is a decision value between the medium frequency and the low frequency,Is a decision value between a high frequency and an intermediate frequency,Is the conductivity of the middle frequency imaginary part,For the low frequency imaginary part conductivity,Is the high frequency imaginary conductivity.
The contaminated area is divided into five different feature types according to a decision criterion, which is as follows:
Type 1: ascending type, imaginary part conductivity Rise with the increase of frequency and are required to meetAnd is also provided with；
Type 2: declining type imaginary part conductivityDecrease with increasing frequency, and is required to meetAnd is also provided with；
Type 3: stable form, imaginary conductivityRemain stable at all frequencies, expressed asAndThe average deviation of (2) is less than 10%, which is satisfied；
Type 4: maximum value type medium frequency imaginary part conductivityFor the maximum value of each frequency range, the requirement is thatAnd is also provided with；
Type 5: minimum value type medium frequency imaginary part conductivityIs the minimum value of each frequency range, and needs to satisfyAnd is also provided with；
Step 5: and calibrating each grid of the polluted area according to the division result of the characteristic types to obtain a characteristic type calibration chart.
The method and the device jointly describe the pollution site by the real part conductivity and the imaginary part conductivity, the real part conductivity is used for judging pollution distribution to obtain a preliminary range, and the range is detailed and partitioned by the imaginary part conductivity. The pollutant types respectively corresponding to the five characteristic types divided according to the determined imaginary part conductivity: establishing an imaginary part conductivity characteristic type case library of different pollution types under different hydrogeologic conditions, and positioning corresponding case types according to the pollution types of the pollution sites and the hydrogeologic conditions; and (3) respectively sampling different characteristic partitions of the field, and determining the corresponding pollution type in an indoor test mode.
Example 2
Taking a specific induced polarization section in a contaminated site as an example, an implementation process of a method for interpreting a contaminated site partition based on time domain induced polarization in the present disclosure includes the following steps:
1. And (3) performing induced polarization measurement on a specific section of the polluted site, determining the length of the measuring line and the electrode spacing according to the field conditions and the detection precision requirements, wherein the length of the measuring line is required to be more than 5d for a target with depth d, and the electrode spacing is required to be less than the resolution of the detection target. And estimating the background resistivity of the target site according to the mineralization degree of the underground water and the stratum type, and determining the data acquisition method of induced polarization according to the background resistivity. For a polluted site with the background resistivity less than 10Ω·m, a double-line data acquisition method of stainless steel electrode power supply and unpolarized electrode measurement is adopted; for a polluted site with the background resistivity greater than 100 omega-m, a single-line data acquisition method for power supply and measurement of a stainless steel electrode is adopted; for a polluted site with the background resistivity between 10 omega-100 omega-m, determining a data acquisition method according to factors such as the background polarization rate, the grounding resistance and the like.
2. After the induced polarization profile is arranged, the induced polarization data measurement parameters are determined according to the characteristics of the field pollutants and the field work requirements. The induced polarization measurement duty ratio is determined by the grounding resistance and the data quality requirement, and 50% or 100% is selected; the time of supply is determined by the characteristic frequency of the pollutant and the requirement of measuring time, and the time of supply is usually 1s to 16 s; the full waveform sampling rate is determined by the characteristic frequency and data storage capacity of the contaminant, typically 1000-10000 Hz; the repeated measurement times are determined by the data quality and the error requirement, and the number of times is 2-4 times optionally; the supply current is determined by the combination of ground resistance, background resistivity, background polarizability and electrode spacing to ensure the strength of the induced polarization signal, optionally 100-1000 mA. And acquiring induced polarization data according to the set measurement parameters.
3. All attenuation curves of the obtained time domain induced polarization view section are converted into view amplitude and view phase information of a frequency domain by a time-frequency conversion method, and the time-frequency conversion schematic of the attenuation curves of each quadrupole array is shown in fig. 2. The frequency spectrum range of the view value and the view phase is determined by the power supply time and the full waveform sampling rate, the lowest frequency is the inverse of the power supply time, and the highest frequency is half of the full waveform sampling rate. And carrying out data processing on the video amplitude and the video phase to obtain a real part video conductivity and an imaginary part video conductivity spectrum curve, wherein the imaginary part video conductivity spectrum curve can reflect full-band spectrum information of the induced polarization of the underground medium so as to reflect the pollution condition of the underground medium.
4. As shown in fig. 3, the frequency spectrum of the real and imaginary apparent resistivity is divided into three frequency bands of high frequency, intermediate frequency, and low frequency. The high-frequency induced polarization information is more sensitive to heavy metal pollution, the medium-frequency induced polarization information is more sensitive to organic pollution, the low-frequency induced polarization information is more sensitive to inorganic salt pollution, and the influence degree of different types of pollutants and different pollution concentrations on each frequency band can be determined through indoor experiments. And carrying out windowing treatment on the virtual part apparent conductivity data of each frequency band to respectively obtain a high-frequency virtual part apparent conductivity representative value, a medium-frequency virtual part apparent conductivity representative value and a low-frequency virtual part apparent conductivity representative value. And windowing is carried out on the low-frequency real part apparent conductivity data, and the obtained low-frequency real part apparent conductivity representative value is used as inversion input of the real part apparent conductivity.
And respectively inverting the imaginary part apparent conductivity representative value and the low-frequency real part apparent conductivity representative value of each frequency band on the view profile, wherein the inversion method uses a windowed inversion technology.
Dividing the induced polarization inversion into two steps, wherein the first step is to invert the visual conductivity data to obtain background conductivity, and calculating a sensitivity matrix of the induced polarization inversion based on the background conductivity; the sensitivity matrix of the polarization rate is calculated by the resistivity sensitivity matrix, the resistivity forward model and the polarization rate forward model; and the second cloth performs inversion by using the calculated induced polarization sensitivity matrix, and the inversion process and the iteration formula are the same as those of resistivity inversion. The inversion results in a real conductivity profile and an imaginary conductivity profile for three bands as shown in fig. 5.
5. Physical relations between the pollution concentration, the real part conductivity and the imaginary part conductivity are established according to the field pollution type, and are shown in figure 4. For a single pollution source, the relation between the concentration of the pollutant and the conductivities of the real part and the imaginary part obtained by a laboratory sand column experiment can be determined, and a physical property relation library of the pollution medium is established by measuring characteristic parameters of induced polarization response of the pollution medium with different concentration gradients, different background conductivities and different particle diameters. For complex site conditions, according to the site drilling sampling test result, the physical relationship between site characteristic pollutant concentration and induced polarization parameters is established corresponding to grid information of the induced polarization profile. And determining a real part conductivity and an imaginary part conductivity threshold according to the relation between the pollution target value and the physical property, and delineating a pollution range according to the threshold.
6. And extracting pixel information of all grids of three frequency bands in the cross section diagram of the imaginary conductivity according to the preliminarily delineated pollution range. For each grid, the relation among high frequency, medium frequency and low frequency is judged, and pollution information is further judged according to the frequency spectrum trend. And calculating a judgment value between the high frequency and the intermediate frequency of the imaginary conductivity and a judgment value between the intermediate frequency and the low frequency so as to reflect the frequency spectrum shape information. The spectral curves are divided into five types shown in fig. 6 according to the determination values, and the imaginary conductivity is represented as a rising type, a falling type, a stable type, a maximum type, and a minimum type with the increase of frequency. And summarizing the frequency spectrum types and the superposition effects corresponding to different pollution subclasses according to laboratory results, and guiding the judgment of pollutants in field investigation.
7. And dividing different types of characteristic partitions in the profile according to the classification result of each grid so as to reflect the pollution partitions. And verifying the detection result by a drilling technology aiming at different characteristic positions and depths on the profile, and evaluating the uncertainty of the result. And guiding a subsequent repair strategy aiming at uncertainty, and realizing efficient and accurate repair of the polluted site.
As an example, in the organic pollution field, the number of electrodes for exciting polarization profile is 64, the electrode spacing is 1 meter, the length of the measuring line is 63 meters, and the detection depth is about 13 meters. The stainless steel electrode is used for power supply, and the data acquisition method of the measurement of the non-polarized electrode is adopted, wherein the distance between the stainless steel electrode and the non-polarized electrode is about 30 cm. The measurement mode with the duty ratio of 100% is adopted, the supply time is 8s, the data sampling rate is 3750 Hz, the repeated measurement times are 2 times, and the supply current is 200 mA.
For the induced polarization section, all the induced polarization full waveform data of 1372 data points are collected, a time-frequency conversion method of fast Fourier transform is selected to convert time domain data into amplitude and phase data of a frequency domain, and the converted data are shown in fig. 2, and the frequency spectrum range is 0.125 Hz to 1875 Hz. And obtaining real part and imaginary part apparent conductivity spectrum curves according to the conversion data and the following formula:
In the method, in the process of the invention, For the real part of the apparent conductivity,For the imaginary part to look at the electrical conductivity,For the amplitude value after the time-frequency transformation,Is the phase after time-frequency conversion.
Frequency division is carried out on the obtained frequency spectrum curve, and for measurement data with the measurement time of 8 seconds, the division standards of high frequency, medium frequency and low frequency are shown in fig. 3: the three frequency bands are high frequency (10-100 Hz), intermediate frequency (1-10 Hz) and low frequency (0.1-1 Hz).
The imaginary apparent conductivity representative value of each frequency band is determined by the following formula:
In the method, in the process of the invention, 、、The high frequency, the medium frequency and the low frequency are respectively the imaginary parts which look at the conductivity representative values,For the number of data points in each frequency band,For the first frequency bandThe frequency of the data points is such that,For the first frequency bandThe imaginary part of the data point is the conductivity. The low-frequency real part apparent conductivity representative value takes the arithmetic average value of all real part apparent conductivities in the low-frequency band.
Inversion is carried out on the imaginary part apparent conductivity representative value and the low-frequency real part apparent conductivity representative value of each frequency band on the view profile diagram, and the real part and imaginary part apparent conductivity representative value profile distribution of the three frequency bands is obtained. During inversion, the coverage of grids is evaluated, grids which do not reach the coverage threshold are not considered in interpretation, the coverage value of each grid is the sum of absolute sensitivity values of all data points normalized according to the cell size, and the coverage value is determined by the following formula:
In the above-mentioned method, the step of, As a result of the unknown parameters,Is a forward model; for the real part conductivity,,For the conductivity of the imaginary part,,. Model parametersAnd the sum is the model coverage rate of parameter distribution, and a coverage threshold value is comprehensively determined according to the depth and the resolution required by the interpretation result.
For the inversion result of the contaminated site, the physical relationship between the contamination concentration and the real part and the virtual part conductivity of the three frequency bands is established as shown in fig. 4, and for the organic contaminated area of the site, the relationship between the contamination concentration and the real part conductivity is established as follows:
In the above-mentioned method, the step of, For the real part of the electrical conductivity,And determining the pollution concentration according to the field corresponding relation.
And according to the established physical relationship and the pollution concentration threshold, combining the pollution restoration target value, and delineating a characteristic pollution area as shown in figure 5. The polluted area represents the total concentration area of the organic pollution, all areas with the total concentration exceeding the standard are divided according to grid pixels, and the information of the areas without exceeding the standard is deleted.
Calculating a judgment value between high frequency and medium frequency and a judgment value between medium frequency and low frequency of the conductivity of the imaginary part of each grid in the final pollution area, wherein the judgment value is calculated according to the following formula:
In the above-mentioned method, the step of, Is a decision value between the medium frequency and the low frequency,Is a decision value between a high frequency and an intermediate frequency,Is the conductivity of the middle frequency imaginary part,For the low frequency imaginary part conductivity,Is the high frequency imaginary conductivity.
The contaminated area is divided into five different feature types according to a decision criterion, which is as follows:
Type 1: ascending type, imaginary part conductivity Rise with the increase of frequency and are required to meetAnd is also provided with；
Type 2: declining type imaginary part conductivityDecrease with increasing frequency, and is required to meetAnd is also provided with；
Type 3: stable form, imaginary conductivityRemain stable at all frequencies, expressed asAndThe average deviation of (2) is less than 10%, which is satisfied；
Type 4: maximum value type medium frequency imaginary part conductivityFor the maximum value of each frequency range, the requirement is thatAnd is also provided with；
Type 5: minimum value type medium frequency imaginary part conductivityIs the minimum value of each frequency range, and needs to satisfyAnd is also provided with；
And calibrating each grid of the polluted area according to the division result of the characteristic types to obtain a characteristic type calibration chart. The contaminant types respectively corresponding to the five characteristic types divided by the determination of the imaginary part conductivity according to the two modes are shown in fig. 7.
Example 3
In one embodiment of the present disclosure, a contaminated site zonal interpretation system based on time domain induced polarization is provided, comprising:
the data acquisition module is used for acquiring full waveform data of induced polarization of the polluted site, and converting all attenuation curves in the full waveform data to obtain a real part apparent conductivity spectrum curve and an imaginary part apparent conductivity spectrum curve;
The data calculation module is used for calculating the real part apparent conductivity representative value under the low frequency band of the real part apparent conductivity spectrum curve and calculating the imaginary part apparent conductivity representative values under the high, medium and low frequency bands of the imaginary part apparent conductivity spectrum curve;
inverting the virtual visual conductivity representative value of each frequency band and the real visual conductivity representative value of the low-frequency band to obtain a real conductivity representative value section of the low-frequency band and an imaginary conductivity representative value section of each frequency band;
The data interpretation module is used for extracting pixel information of all grids of each frequency band in the pollution area in the section of the representative value of the imaginary conductivity according to the field pollution type and concentration and the physical relationship between the real part and the imaginary part conductivity; calculating a judgment value between each frequency band of the imaginary part conductivity representative value in each grid, and dividing the pollution area into different characteristic types according to a judgment standard; and determining the pollutant types corresponding to the different characteristic types to realize the partitioning of the polluted area.
Example 4
In one embodiment of the present disclosure, a non-transitory computer readable storage medium is provided for storing computer instructions that, when executed by a processor, implement the contaminated site partition interpretation method based on time domain induced polarization.
Example 5
In one embodiment of the present disclosure, there is provided an electronic device including: a processor, a memory, and a computer program; wherein the processor is coupled to the memory and the computer program is stored in the memory, the processor executing the computer program stored in the memory when the electronic device is operating, to cause the electronic device to perform the contaminated site partition interpretation method implementing the time domain induced polarization based method.
The present disclosure is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the disclosure. It will be understood that each flow and/or block of the flowchart illustrations and/or block diagrams, and combinations of flows and/or blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
While the specific embodiments of the present disclosure have been described above with reference to the drawings, it should be understood that the present disclosure is not limited to the embodiments, and that various modifications and changes can be made by one skilled in the art without inventive effort on the basis of the technical solutions of the present disclosure while remaining within the scope of the present disclosure.
Claims (8)
1. The method for interpreting the contaminated site partition based on the time domain induced polarization is characterized by comprising the following steps:
Acquiring full waveform data of induced polarization of a contaminated site, and converting all attenuation curves in the full waveform data to obtain a real part apparent conductivity spectrum curve and an imaginary part apparent conductivity spectrum curve;
calculating a real part apparent conductivity representative value under a low frequency band of the real part apparent conductivity spectrum curve, and calculating imaginary part apparent conductivity representative values under high, medium and low frequency bands of the imaginary part apparent conductivity spectrum curve;
inverting the virtual visual conductivity representative value of each frequency band and the real visual conductivity representative value of the low-frequency band to obtain a real conductivity representative value section of the low-frequency band and an imaginary conductivity representative value section of each frequency band;
Extracting pixel information of all grids of each frequency band in a pollution area in a section of the imaginary part conductivity representative value according to the field pollution type, concentration and physical relation between the real part conductivity and the imaginary part conductivity; calculating a judgment value between each frequency band of the imaginary part conductivity representative value in each grid, and dividing the pollution area into different characteristic types according to a judgment standard;
for inversion results of a pollution site, physical property relations between pollution concentration and low-frequency real part and three-frequency band imaginary part conductivities are established, and for an organic pollution area, the relations between the pollution concentration and the real part conductivities are established as follows:
for heavy metal pollution areas, the relationship between the pollution concentration and the conductivities of the real part and the imaginary part is established as follows:
for the inorganic salt pollution area, the relation between the pollution concentration and the electric conductivity of the real part and the imaginary part is established as follows:
In the above-mentioned method, the step of, For the real part of the electrical conductivity,For the conductivity of the imaginary part,In order to achieve a concentration of the contaminants,For parameters to be estimated, determining physical property relations of each frequency band according to the field corresponding relation or laboratory samples;
and (3) according to the established physical relationship and a pollution concentration threshold, combining a pollution restoration target value, and delineating a characteristic pollution area:
In the above-mentioned method, the step of, In order to be able to finally contaminate the area,For contaminated areas delineated by high frequencies,For a contaminated area delineated by the intermediate frequency,A contaminated area delineated for low frequencies; the final pollution area represents the total concentration area of organic pollution, heavy metal pollution or inorganic salt pollution, all areas with total concentration exceeding the standard are divided according to grid pixels, and the information of the areas without exceeding the standard is deleted; calculating a judgment value between high frequency and medium frequency and a judgment value between medium frequency and low frequency of the conductivity of the imaginary part of each grid in the final pollution area, wherein the judgment value is calculated according to the following formula:
In the above-mentioned method, the step of, Is a decision value between the medium frequency and the low frequency,Is a decision value between a high frequency and an intermediate frequency,Is the conductivity of the middle frequency imaginary part,For the low frequency imaginary part conductivity,The conductivity of the high-frequency imaginary part;
The contaminated area is divided into five different feature types according to a decision criterion, which is as follows:
Type 1: ascending type, imaginary part conductivity Rise with the increase of frequency and are required to meetAnd is also provided with；
Type 2: declining type imaginary part conductivityDecrease with increasing frequency, and is required to meetAnd is also provided with；
Type 3: stable form, imaginary conductivityRemain stable at all frequencies, expressed asAndThe average deviation of (2) is less than 10%, which is satisfied；
Type 4: maximum value type medium frequency imaginary part conductivityFor the maximum value of each frequency range, the requirement is thatAnd is also provided with；
Type 5: minimum value type medium frequency imaginary part conductivityIs the minimum value of each frequency range, and needs to satisfyAnd is also provided with；
And determining the pollutant types corresponding to the different characteristic types to realize the partitioning of the polluted area.
2. The method for analyzing the polluted site partition based on the time domain induced polarization according to claim 1, wherein the induced polarization profile of the polluted site is obtained, the induced polarization full waveform data of all data points are collected, all attenuation curve time domain data of the full waveform data are converted into amplitude and phase data of a frequency domain by using a time-frequency conversion method, and a real part visual conductivity spectrum curve and an imaginary part visual conductivity spectrum curve are calculated respectively.
3. The method for analyzing the polluted site partition based on the time domain induced polarization as claimed in claim 1, wherein the frequency bands are divided into three frequency bands of high frequency, medium frequency and low frequency, respectively, and the division standards of the high frequency, the medium frequency and the low frequency are as follows: when the measurement time is 8 seconds or more, 10-100 Hz is high frequency, 1-10 Hz is medium frequency, and 0.1-1 Hz is low frequency; when the measurement time is 1-8 seconds, 20-100 Hz is high frequency, 5-20 Hz is medium frequency, 1-5 Hz is low frequency, according to the divided frequency bands, the real part visual conductivity representative value under the low frequency band of the real part visual conductivity spectrum curve is calculated, and the imaginary part visual conductivity representative value under the high, medium and low frequency bands of the imaginary part visual conductivity spectrum curve is calculated.
4. The method for analyzing the contaminated site partition based on time domain induced polarization according to claim 1, wherein the inversion is performed on the imaginary part apparent conductivity representative value of each frequency band and the real part apparent conductivity representative value of the low frequency band, the coverage of grids is determined in the inversion process, grids which do not reach the coverage threshold are not considered in the analysis, and the coverage value of each grid is the sum of absolute sensitivity values of all data points normalized according to the cell size.
5. The method for analyzing the polluted site partition based on the time domain induced polarization according to claim 1, wherein the polluted region is divided into five different characteristic types according to a judging standard, namely an ascending type, a descending type, a stable type, a maximum type and a minimum type, and each grid of the polluted region is calibrated according to the division result of the characteristic types to obtain calibration diagrams of different characteristic types.
6. A contaminated site zoning interpretation system based on time domain induced polarization, characterized by embodying the method for contaminated site zoning interpretation based on time domain induced polarization as claimed in any one of claims 1 to 5, comprising:
the data acquisition module is used for acquiring full waveform data of induced polarization of the polluted site, and converting all attenuation curves in the full waveform data to obtain a real part apparent conductivity spectrum curve and an imaginary part apparent conductivity spectrum curve;
The data calculation module is used for calculating the real part apparent conductivity representative value under the low frequency band of the real part apparent conductivity spectrum curve and calculating the imaginary part apparent conductivity representative values under the high, medium and low frequency bands of the imaginary part apparent conductivity spectrum curve;
inverting the virtual visual conductivity representative value of each frequency band and the real visual conductivity representative value of the low-frequency band to obtain a real conductivity representative value section of the low-frequency band and an imaginary conductivity representative value section of each frequency band;
The data interpretation module is used for extracting pixel information of all grids of each frequency band in the pollution area in the section of the representative value of the imaginary conductivity according to the field pollution type and concentration and the physical relationship between the real part and the imaginary part conductivity; calculating a judgment value between each frequency band of the imaginary part conductivity representative value in each grid, and dividing the pollution area into different characteristic types according to a judgment standard; and determining the pollutant types corresponding to the different characteristic types to realize the partitioning of the polluted area.
7. A non-transitory computer readable storage medium storing computer instructions which, when executed by a processor, implement the contaminated site partition interpretation method based on time domain induced polarization of any of claims 1-5.
8. An electronic device, comprising: a processor, a memory, and a computer program; wherein the processor is connected to the memory, and wherein the computer program is stored in the memory, which processor, when the electronic device is running, executes the computer program stored in the memory to cause the electronic device to perform the method for implementing the time domain induced polarization based contaminated site partition interpretation method according to any of the claims 1-5.
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