A method and system for monitoring railway subgrade collapse

Abstract

This application relates to the field of subsidence monitoring, and specifically relates to a method and system for monitoring railway subgrade subsidence. The method includes: obtaining the reflected wave signals detected by a ground penetrating radar each time in each subgrade section; obtaining the dielectric significance based on the degree of outliers of the energy of the reflected wave signals in each subgrade section; obtaining the signal bending amount based on the convergence and divergence of the frequency distribution of the reflected wave signals in the frequency domain; obtaining the water content evaluation value for each subgrade section in each detection, and screening the sections to be confirmed; analyzing the change of the signal bending amount of the reflected wave signals in each subgrade section to be confirmed during consecutive detections, and obtaining the static continuity of each subgrade section to be confirmed; based on the static continuity and the water content evaluation value of each subgrade section to be confirmed in each detection, obtaining the subsidence possibility of each subgrade section to be confirmed in each detection. This application aims to improve the accuracy of subgrade subsidence monitoring.

Description

Technical Field

[0001] This application relates to the field of subsidence monitoring, and specifically to a method and system for monitoring railway subgrade subsidence. Background Art

[0002] In railway subgrade subsidence monitoring, common technical means include surface deformation monitoring, ground penetrating radar detection, fiber optic sensor monitoring, and tilt sensors. Among them, in order to efficiently and accurately detect underground structures, ground penetrating radar (GPR) technology is widely used. Its basic principle is to utilize the reflection characteristics of electromagnetic waves when propagating in different media, and identify abnormal changes in underground structures by analyzing the reflection signals of underground media (such as cavities, moisture changes, or soil density). Ground penetrating radar can provide fast and real-time underground detection results, and is an effective means for monitoring abnormal structures such as underground defects, cracks, or cavities.

[0003] The water content of subgrade soil plays a crucial role in the process of subsidence judgment. Through real-time monitoring by ground penetrating radar detection technology, based on the characteristics of reflected waves, the water content can be quickly evaluated. However, during the monitoring process, due to the uneven density of some soil materials, it will cause fluctuations in the dielectric constant, which are similar to the characteristics of moisture areas, thus possibly leading to misjudgment of water content, and further affecting the accurate monitoring and evaluation of subgrade subsidence. Summary of the Invention

[0004] In view of the above, it is necessary to provide a method and system for monitoring railway subgrade subsidence to solve the above problems.

[0005] The first aspect of this application provides a method for monitoring railway subgrade subsidence, and the method includes:

[0006] Obtain the reflected wave signals detected by the ground penetrating radar for each subgrade section each time;

[0007] Based on the degree of outlier of the energy of the reflected wave signals of each subgrade section in each detection among all subgrade sections, obtain the dielectric significance of each subgrade section in each detection;

[0008] Perform frequency domain transformation on the reflected wave signals of each subgrade section in each detection, mark the frequency based on the amplitude change in the frequency domain; according to the convergence and divergence of the distribution of the marked frequencies, obtain the signal bending amount of each subgrade section in each detection; based on the signal bending amount and dielectric significance, obtain the water content evaluation value of each subgrade section in each detection, and screen the sections to be confirmed;

[0009] Analyze the change in the signal bending amount of the reflected wave signals during consecutive detections for each subgrade section to be confirmed, and obtain the static continuity of each subgrade section to be confirmed; based on the static continuity and water content evaluation value of each subgrade section to be confirmed in each detection, obtain the collapse possibility of each subgrade section to be confirmed in each detection.

[0010] Among them, obtaining the dielectric significance of each subgrade section in each detection specifically includes:

[0011] Taking the reflected wave signal energy of all subgrade sections in each detection as a sample, obtain the outlier degree of the reflected wave signal energy of each subgrade section; take the normalized value of the product of the reflected wave signal energy and the outlier degree as the dielectric significance of each subgrade section in each detection.

[0012] Among them, the process of marking the frequency is as follows:

[0013] Perform normalization processing on all frequency amplitudes of the reflected wave signals of each subgrade section in each detection, and mark the frequencies whose normalized values of the frequency amplitudes are greater than the preset threshold.

[0014] Among them, the steps of obtaining the signal bending amount of each subgrade section in each detection are as follows:

[0015] According to the span and number of the marked frequencies of the reflected wave signals of each subgrade section in each detection, obtain the signal irregularity amount of the reflected wave signals of each subgrade section in each detection;

[0016] For the reflected wave signals of each subgrade section in each detection, obtain the degree of chaos of the marked frequencies; take the fusion result of the degree of chaos and the signal irregularity amount as the signal bending amount of each subgrade section in each detection.

[0017] Among them, the process of obtaining the signal irregularity amount of the reflected wave signals of each subgrade section in each detection specifically includes:

[0018] Obtain the extreme difference of the marked frequencies; fuse the number of marked frequencies and the extreme difference to obtain the signal irregularity amount of each subgrade section in each detection.

[0019] Among them, the water content evaluation value of each subgrade section in each detection is specifically the normalized value of the product of the signal bending amount and the dielectric significance.

[0020] Among them, the process of screening the sections to be confirmed is specifically as follows: when the water content evaluation value is greater than or equal to the preset evaluation threshold, mark the corresponding subgrade section as a section to be confirmed.

[0021] Among them, the process of obtaining the static continuity of each subgrade section to be confirmed is specifically as follows:

[0022] Taking each detection and the previous preset number of detections as a detection interval, obtaining the difference in the signal bending amount of adjacent reflected wave signals in each detection interval for each subgrade section to be confirmed, and averaging the negative correlation mapping results of all the differences in each detection interval for each subgrade section to be confirmed, to obtain the static continuity of each subgrade section to be confirmed in each detection.

[0023] Among them, the specific method for obtaining the collapse possibility of each subgrade section to be confirmed in each detection is as follows:

[0024] Calculating the difference between the value 1 and the static continuity, and determining the normalized value obtained by multiplying the difference by the water content evaluation value as the collapse possibility of the subgrade section to be confirmed in each detection.

[0025] In a second aspect, an embodiment of the present application further provides a railway subgrade collapse monitoring system, including a memory, a processor, and a computer program stored in the memory and running on the processor. When the processor executes the computer program, the steps of the method described in any one of the above are implemented.

[0026] The present application has at least the following beneficial effects:

[0027] By analyzing the energy distribution of the reflected wave signals detected by the ground penetrating radar for each subgrade section each time, the dielectric significance of each subgrade section in each detection is obtained, effectively reducing subsequent misjudgments caused by factors such as differences in material density and soil types of subgrade sections, being able to more accurately distinguish the relationship between changes caused by moisture and changes in other physical characteristics, and improving the judgment accuracy of subgrade collapse; marking the frequency based on the amplitude change in the frequency domain, and obtaining the signal bending amount of each subgrade section in each detection according to the convergence and divergence of the distribution of the marked frequencies. Through the analysis of the convergence and divergence of the frequency distribution, the state of the subgrade can be more accurately evaluated, reducing errors caused by external environmental factors and improving the accuracy of the detection results; based on the signal bending amount and dielectric significance, obtaining the water content evaluation value of each subgrade section in each detection, screening the sections to be confirmed, reducing the subsequent calculation amount and improving the efficiency; analyzing the change of the signal bending amount of the reflected wave signals during consecutive detections for each subgrade section to be confirmed, obtaining the static continuity of each subgrade section to be confirmed, analyzing the overall reflected wave signals obtained continuously for multiple times, and eliminating interference from other materials according to the characteristics of water content variation in the subgrade area, obtaining the collapse possibility of the subgrade, and realizing the precise monitoring of subgrade collapse. Description of the Drawings

[0028] Figure 1 It is a flowchart of the steps of a railway subgrade collapse monitoring method provided by an embodiment of the present application;

[0029] Figure 2 Flowchart for obtaining the possibility of subsidence provided by an embodiment of the present application. Detailed implementation manners

[0030] In the description of the embodiments of the present application, words such as "exemplary", "or", "for example", etc. are used to indicate examples, illustrations or explanations. Any embodiment or design solution described as "exemplary" or "for example" in the embodiments of the present application should not be construed as being more preferred or having more advantages than other embodiments or design solutions. Exactly speaking, using words such as "exemplary", "or", "for example", etc. aims to present relevant concepts in a specific way.

[0031] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which this application belongs. The terms used in the description of this application are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0032] In addition, it should be noted that the terms "first" and "second" in this application and the accompanying drawings are used to distinguish similar objects and are not used to describe a specific order or sequence. For the methods disclosed in the embodiments of this application or the methods shown in the flowcharts, including one or more steps for implementing the methods, without departing from the protection scope of this application, the execution order of multiple steps can be interchanged with each other, and some steps can also be deleted.

[0033] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which this application belongs.

[0034] The following specifically describes the specific solutions of a railway subgrade subsidence monitoring method and system provided by this application with reference to the accompanying drawings.

[0035] Please refer to Figure 1 , which shows the step flowchart of a railway subgrade subsidence monitoring method provided by an embodiment of this application. The method includes the following steps:

[0036] The first step: Obtain the reflected wave signals detected by the ground penetrating radar each time in each subgrade section.

[0037] Ground penetrating radar devices are arranged in different subgrade sections of the railway subgrade, and each radar covers a certain monitoring range. In this embodiment, the resolution of the ground penetrating radar device used is: 0.1~0.5m, which is used to capture subtle changes; the detection depth range is 0.5~3m; the radar frequency range is: 250MHz~1GHz, and the implementer can select a suitable frequency range according to the detection depth and resolution requirements; the signal acquisition frequency is 100Hz, and the reflected wave signals are collected every 30 minutes; the implementer can adjust according to the actual situation.

[0038] Second step: Based on the degree of outlier of the energy of the reflected wave signal of each subgrade section in each detection of all subgrade sections, obtain the dielectric significance of each subgrade section in each detection.

[0039] The reflected wave signal collected each time comes from the electromagnetic wave propagating to the strata at different depths underground and is reflected when encountering different media. The waveform characteristics of the reflected wave signal can reflect geological characteristics such as the density and moisture content of the area. In particular, the moisture content has a significant impact on the dielectric constant of the soil because the high dielectric constant of water will greatly enhance the intensity of the reflected wave signal. In areas with a higher moisture content, the signal amplitude of the reflected wave increases significantly, and the energy value of the reflected wave signal is significantly higher compared to other areas. In addition, areas with a higher moisture content often cause the reflected waveform to become irregular, even showing local bending or damage.

[0040] Calculating the energy of the reflected wave signal based on the amplitude of the reflected wave signal of each subgrade section in each detection is a well-known prior art, and this application will not elaborate; based on the degree of outlier of the energy of the reflected wave signal of each subgrade section in each detection of all subgrade sections, obtain the dielectric significance of each subgrade section in each detection: taking the energy of the reflected wave signal of all subgrade sections in each detection as a sample, obtaining the degree of outlier of the energy of the reflected wave signal of each subgrade section; taking the normalized value of the product of the energy of the reflected wave signal and the degree of outlier as the dielectric significance of each subgrade section in each detection.

[0041] In this embodiment, the degree of outlier is measured by the Z-score, and the Z-score is a well-known prior art, and this application will not elaborate on it; in addition, the method of normalization uses the maximum-minimum method.

[0042] It should be understood that the larger the energy value of each subgrade section and the stronger the outlier property, it means that the moisture content of the subgrade section is higher, resulting in a greater possibility of dielectric constant change, and its dielectric significance is correspondingly higher.

[0043] Third step: Perform frequency domain transformation on the reflected wave signal of each subgrade section in each detection, mark the frequency based on the amplitude change in the frequency domain; obtain the signal bending amount of each subgrade section in each detection according to the distribution convergence and divergence of the marked frequencies; based on the signal bending amount and the dielectric significance, obtain the water content evaluation value of each subgrade section in each detection, and screen the sections to be confirmed.

[0044] Due to the effect of moisture diffusion, the reflected wave signal usually exhibits irregular or bent characteristics. Therefore, in the frequency domain, the high-amplitude frequency region of the signal will show a more dispersed distribution.

[0045] The reflected wave signals of each subgrade section in each detection are subjected to Fourier transform, the frequencies are marked based on the amplitude changes in the frequency domain, and according to the span and number of the marked frequencies, the signal irregularity is obtained: all the frequency amplitudes of the reflected wave signals of each subgrade section in each detection are normalized, and the frequencies with the normalized values of the frequency amplitudes greater than the preset threshold are marked; the extreme difference value of the marked frequencies is obtained; the number of the marked frequencies is fused with the extreme difference value to obtain the signal irregularity of each subgrade section in each detection.

[0046] In this embodiment, the sigmoid function is used for normalization, and the preset threshold value is 0.6, which can be adjusted by the implementer himself; when fusing multiple variables, the multiplication method is adopted, that is, the signal irregularity is specifically the product of the number of the marked frequencies and the extreme difference value.

[0047] It should be understood that if there are more marked frequency components and these frequencies are more dispersed, it means that the bandwidth of the signal is wider, reflecting that the signal contains more components of different frequencies. This phenomenon usually indicates that the frequency range of the reflected wave signal is wider and its irregularity or complexity is higher. The increase in bandwidth means that the frequency components of the signal are more abundant, which is in line with the characteristics of electromagnetic waves reflected in areas with more moisture, because an environment with more moisture will cause the expansion of the reflected wave frequency range and more complex signal characteristics.

[0048] Further, based on the frequency distribution of the reflected wave signals of each subgrade section in each detection in the frequency domain and in combination with the signal irregularity, the signal bending amount of each subgrade section in each detection is obtained: for the reflected wave signals of each subgrade section in each detection, the degree of chaos of the marked frequencies is obtained; the fusion result of the degree of chaos and the signal irregularity is used as the signal bending amount of each subgrade section in each detection. In this embodiment, the entropy value is used to measure the degree of chaos of the frequencies; when fusing multiple variables, the multiplication calculation method is adopted.

[0049] It should be understood that the frequency distribution will affect the irregularity of the signal. The more chaotic the frequency distribution is, it means that in the frequency domain, the intensity of some frequencies may suddenly increase or decrease. This uneven frequency distribution will cause the signal to show complex and irregular fluctuations in the time domain, making the signal look irregular; if the frequencies of the signal are relatively evenly distributed in the frequency domain, then the time-domain performance of the signal may be relatively regular.

[0050] Calculate the normalized value of the product of the signal bending amount and the dielectric significance to obtain the water content evaluation value of each subgrade section in each detection; when the water content evaluation value is greater than or equal to the preset evaluation threshold, the corresponding subgrade section is marked as a section to be confirmed. In this embodiment, the normalization method adopts the maximum-minimum value method, and the evaluation threshold value is 0.8, which can be adjusted by the implementer himself.

[0051] It should be understood that if the evaluated water content value of a subgrade section in this detection is greater than or equal to the evaluation threshold, the greater the possibility of collapse of this subgrade section, and further confirmation is required; if the evaluated water content values of all subgrade sections in this detection are less than the evaluation threshold, it indicates that there is no collapse in the subgrade section, and it is necessary to wait for the next detection.

[0052] The fourth step: Analyze the change of the signal bending amount of the reflected wave signal of each subgrade section to be confirmed during consecutive detections, and obtain the static continuity of each subgrade section to be confirmed; based on the static continuity and the evaluated water content value of each subgrade section to be confirmed in each detection, obtain the collapse possibility of each subgrade section to be confirmed in each detection.

[0053] Different types of subgrade materials, such as soil, sand and gravel, clay, etc., have their own different natural dielectric constants. When these materials are mixed or distributed unevenly, it may cause changes in signal reflection, similar to the phenomenon caused by an increase in moisture content. In addition, changes in the looseness or compaction state of the subgrade will also affect the reflection intensity of the medium on the radar wave, resulting in an enhancement of the radar signal or more signal disturbances. Therefore, the evaluated water content value is only one of the necessary conditions for identification. In order to make a more accurate distinction, it is also necessary to analyze and process in combination with the dynamic changes in the area with a higher water content.

[0054] Dynamic variability means that during multiple detections, the radar signals in the water-saturated area usually show the characteristics of gradual enhancement and expansion, that is, as the moisture accumulates or diffuses, the reflection intensity of the signal will gradually increase, and this change shows a continuous trend. Compared with other areas, the reflection parameters in the water-saturated area are relatively stable at different time points. Therefore, in order to accurately distinguish these areas, it is necessary to monitor consecutive reflected wave signals and analyze their dynamic change characteristics.

[0055] Analyze the change of the signal bending amount of the reflected wave signal of each subgrade section to be confirmed during consecutive detections, and obtain the static continuity of each subgrade section to be confirmed: Take each detection and the previously preset number of detections as a detection interval, obtain the difference in the signal bending amount of adjacent reflected wave signals of each subgrade section to be confirmed in each detection interval, and average the negative correlation mapping results of all the differences of each subgrade section to be confirmed in each detection interval to obtain the static continuity of each subgrade section to be confirmed in each detection. In this embodiment, the preset number is 23, and the implementer can adjust it according to the actual situation; the difference between variables is measured by the absolute value of the difference; the negative correlation mapping result of the difference is specifically the reciprocal of the difference. It should be noted that in order to avoid the denominator being 0, a constant greater than zero needs to be added to the denominator, and the value is 1.

[0056] It should be understood that the smaller the difference in the signal bending amount of the reflected wave signals between two adjacent detections, the closer the negative correlation mapping result is to 1, indicating that due to the fixed nature of the subgrade section, the characteristics of the reflected wave signals under different detections remain consistent; while in the area with high moisture content, it usually shows a gradually increasing and spreading trend, that is, the larger the difference in the signal bending amount of the reflected wave signals between two adjacent detections, the smaller the difference value of the negative correlation mapping result is less than 1, meaning that the dynamic characteristics of the signal are more obvious and can better reflect the change law of the water content area.

[0057] Furthermore, based on the static continuity and water content evaluation value of each subgrade section to be confirmed in each detection, obtain the collapse possibility of each subgrade section to be confirmed in each detection: calculate the difference between 1 and the static continuity, and multiply the difference by the normalized value of the water content evaluation value to obtain the collapse possibility of the subgrade section to be confirmed in each detection.

[0058] Among them, the flow chart for obtaining the collapse possibility is as Figure 2 shown.

[0059] Based on the same inventive concept as the above method, an embodiment of the present application further provides a railway subgrade collapse monitoring system, including a memory, a processor, and a computer program stored in the memory and running on the processor. When the processor executes the computer program, it implements the steps of any one of the above-mentioned railway subgrade collapse monitoring methods.

[0060] To sum up, the present application analyzes the energy distribution of the reflected wave signals detected by the ground penetrating radar in all subgrade sections each time, obtains the dielectric significance of each subgrade section in each detection, effectively reduces subsequent misjudgments caused by factors such as differences in material density and soil types of subgrade sections, and can more accurately distinguish the relationship between changes caused by moisture and changes in other physical characteristics, improving the judgment accuracy of subgrade collapse; marks the frequency based on the amplitude change in the frequency domain, and obtains the signal bending amount of each subgrade section in each detection according to the convergence and divergence of the distribution of the marked frequencies. Through the analysis of the convergence and divergence of the frequency distribution, the state of the subgrade can be more accurately evaluated, reducing errors caused by external environmental factors and improving the accuracy of the detection results; based on the signal bending amount and dielectric significance, obtains the water content evaluation value of each subgrade section in each detection, screens the sections to be confirmed, reduces the subsequent calculation amount and improves the efficiency; analyzes the change of the signal bending amount of the reflected wave signals of each subgrade section to be confirmed during consecutive detections, obtains the static continuity of each subgrade section to be confirmed, analyzes the overall reflected wave signals obtained continuously for multiple times, and eliminates interference from other materials according to the characteristics of water content changes in the subgrade area, obtains the collapse possibility of the subgrade, and realizes the accurate monitoring of subgrade collapse.

[0061] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to embodiments of the present application. In this regard, each block in the flowchart or block diagram may represent a module, a segment of a program, or a part of code, which contains one or more executable instructions for implementing the specified logical function. In some alternative implementations, the functions noted in the blocks may occur in an order different from that noted in the accompanying drawings. For example, two consecutive blocks may actually be executed substantially in parallel, or they may sometimes be executed in the reverse order, depending on the functions involved. In the description corresponding to the flowcharts and block diagrams in the accompanying drawings, the operations or steps corresponding to different blocks may also occur in an order different from that disclosed in the description, and sometimes there is no specific order between different operations or steps. For example, two consecutive operations or steps may actually be executed substantially in parallel, or they may sometimes be executed in the reverse order, depending on the functions involved. Each block in the block diagram and / or flowchart, and combinations of blocks in the block diagram and / or flowchart, may be implemented by a dedicated hardware-based system that performs the specified functions or actions, or may be implemented by a combination of dedicated hardware and computer instructions.

[0062] For those skilled in the art, it is obvious that the present application is not limited to the details of the above-described exemplary embodiments, and without departing from the basic characteristics of the present application, the present application can be implemented in other specific forms. Therefore, from any point of view, the above-described embodiments of the present application should be regarded as exemplary and non-limiting; modifying the technical solutions described in the foregoing embodiments, or equivalently replacing some of the technical features, does not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.

Claims

1. A method for monitoring railway subgrade collapse, characterized in that, The method includes the following steps: Obtain the reflected wave signals detected by the ground penetrating radar each time in each subgrade section; Take the energy of the reflected wave signals in each detection of all subgrade sections as samples, and obtain the degree of outlier of the reflected wave signal energy of each subgrade section; Take the normalized value of the product of the reflected wave signal energy and the degree of outlier as the dielectric significance of each subgrade section in each detection; Perform frequency domain transformation on the reflected wave signals of each subgrade section in each detection, and mark the frequency based on the amplitude change in the frequency domain; According to the span and number of the marked frequencies of the reflected wave signals of each subgrade section in each detection, obtain the signal irregularity of the reflected wave signals of each subgrade section in each detection; For the reflected wave signals of each subgrade section in each detection, obtain the degree of chaos of the marked frequencies; Take the fusion result of the degree of chaos and the signal irregularity as the signal bending amount of each subgrade section in each detection; Based on the signal bending amount and the dielectric significance, obtain the water content evaluation value of each subgrade section in each detection, and screen the sections to be confirmed; Take each detection and the previous preset number of detections as a detection interval, obtain the difference in the signal bending amount of adjacent reflected wave signals of each subgrade section to be confirmed in each detection interval, and average the negative correlation mapping results of all the differences of each subgrade section to be confirmed in each detection interval to obtain the static continuity of each subgrade section to be confirmed in each detection; Based on the static continuity and the water content evaluation value of each subgrade section to be confirmed in each detection, obtain the collapse possibility of each subgrade section to be confirmed in each detection.

2. The method for monitoring railway subgrade collapse according to claim 1, characterized in that The process of marking the frequency is as follows: Normalize all the frequency amplitudes of the reflected wave signals of each subgrade section in each detection, and mark the frequencies whose normalized values of the frequency amplitudes are greater than the preset threshold.

3. The railway subgrade subsidence monitoring method according to claim 1, characterized in that, The specific method for obtaining the signal irregularity of the reflected wave signals of each subgrade section in each detection is as follows: Obtain the extreme difference of the marked frequencies; Fuse the number of the marked frequencies and the extreme difference to obtain the signal irregularity of each subgrade section in each detection.

4. The method for monitoring railway subgrade collapse according to claim 1, characterized in that The water content evaluation value of each subgrade section in each detection is specifically the normalized value of the product of the signal bending amount and the dielectric significance.

5. The railway subgrade subsidence monitoring method according to claim 1, characterized in that, The process of screening the sections to be confirmed is specifically as follows: When the water content evaluation value is greater than or equal to the preset evaluation threshold, mark the corresponding subgrade section as the section to be confirmed.

6. The railway subgrade collapse monitoring method according to claim 1, characterized in that, The specific method for obtaining the collapse possibility of each subgrade section to be confirmed in each detection is as follows: Calculate the difference between the value 1 and the static continuity, and take the normalized value of the product of the difference and the water content evaluation value as the collapse possibility of the subgrade section to be confirmed in each detection.

7. A railway subgrade collapse monitoring system, comprising a memory, a processor, and a computer program stored in the memory and running on the processor, characterized in that, When the processor executes the computer program, it implements the steps of the method according to any one of claims 1-6.

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