A system and method for monitoring the development process of artificial frozen soil frozen wall based on Rayleigh waves

Abstract

The present invention discloses a system and method for monitoring the development of artificial frozen soil and frozen walls based on Rayleigh waves, which relates to the field of acoustic wave detection. The system comprises the following steps: calculating the wavelength of the required Rayleigh wave based on the range of frozen wall detection depth required for the monitoring project; disposing a plurality of acceleration sensors on the surface of the rock mass area to be detected, determining the spacing between the acceleration sensors based on the obtained Rayleigh wave wavelength, and marking the midpoint of the line connecting adjacent acceleration sensors as the excitation point; applying a Rayleigh wave of a specific wavelength at the excitation point, collecting raw waveform data, extracting corresponding frequency data, and obtaining a Rayleigh wave velocity map through Fourier transform; obtaining a dispersion curve based on the excited frequency data and Rayleigh wave velocity, and identifying the first inflection point where a zigzag Rayleigh wave velocity difference appears in the graph; obtaining the velocity at the inflection point from the image, and calculating the actual value of the frozen wall burial depth based on the inflection point occurrence time and the Rayleigh wave velocity at the inflection point.

Description

Technical Field

[0001] The present invention relates to the field of acoustic wave detection technology, and in particular to a system and method for monitoring the development process of artificial frozen soil frozen wall based on Rayleigh waves. Background Art

[0002] Artificial freezing technology is a common method for pre-reinforcement of soft rock foundations, water-rich sand layers, and highly pressurized water strata to ensure stability and safety during tunnel construction. It was first used as a temporary support method. Researchers discussed various factors that affect the selection of freezing temperature, freezing zone thickness, and freezing pipe spacing, providing new directions for the application of artificial freezing method.

[0003] However, when using artificial freezing techniques, soil expansion or other problems during the freeze-thaw process can seriously affect the construction process and lead to serious accidents. Therefore, monitoring the freeze-thaw process and the development of frozen walls during the freezing construction process is crucial. Generally, researchers insert temperature sensors into the frozen soil to obtain the soil freezing temperature and conduct numerical simulation analysis to study the changes in soil during the freeze-thaw process.

[0004] Rayleigh waves, the result of interference between longitudinal and shear waves, typically exhibit relatively low velocity, low frequency, and high amplitude. Rayleigh wave surveying is a low-cost, highly efficient, and highly accurate nondestructive testing technique. Rayleigh wave detection techniques can be used to assess the variation of shear velocity with depth based on the dispersion characteristics of Rayleigh waves. Therefore, soil conditions at different depths can be monitored based on the variation in wave velocity at different depths.

[0005] Therefore, due to the dispersion characteristics of Rayleigh waves, significant variations in wave velocity occur between frozen and unfrozen soil. Based on this fact, the detection device can detect the development of frozen walls during the freezing process and verify the applicability of Rayleigh wave-based nondestructive testing techniques for artificial freezing detection. More importantly, the theory and experiments proposed in this study can provide valuable reference for the future application of Rayleigh wave detection technology in on-site monitoring of freeze-thaw development in soil during artificial freezing construction.

[0006] Prior art publication CN108468321A discloses a method for ultrasonically monitoring the development of frozen walls. The method involves the following steps: before a frozen wall forms, monitoring holes are arranged around the wellbore based on geological conditions. The depth of the monitoring holes is generally 1.2 times the desired freezing depth. Two ultrasonic integrators are arranged vertically and horizontally within a conduit through a pre-set hole, spaced at a predetermined distance. The ultrasonic integrators receive and transmit ultrasonic waves. Once the ultrasonic integrators are fully positioned, the pre-set hole is sealed with tape. The integrators within the conduit transmit signals via wires to a computer. The computer data processing system processes the data, generating a curve of ultrasonic wave velocity changes and analyzing the frozen wall development. However, this method is subject to attenuation of ultrasonic wave propagation in materials, particularly in media such as soil or rock, which can weaken the signal and affect the accuracy and reliability of the data. Furthermore, the design depth and layout of the monitoring holes may be limited, failing to cover all important areas of the frozen wall, potentially resulting in incomplete monitoring results.

[0007] The above information disclosed in this Background section is only for enhancement of understanding of the background of the present disclosure and therefore it may contain information that does not form the prior art that is already known to a person of ordinary skill in the art. Summary of the Invention

[0008] The object of the present invention is to provide a system and method for monitoring the development process of artificial frozen soil and frozen wall based on Rayleigh waves, so as to solve the problems raised in the above background technology.

[0009] To achieve the above object, the present invention provides the following technical solutions:

[0010] A Rayleigh wave-based monitoring system for the development of artificial frozen soil and frozen walls, specifically comprising:

[0011] A Rayleigh wave wavelength analysis module is used to determine the rock and soil area to be detected, set the detection depth range of the rock and soil area to be detected, and calculate the wavelength of the required Rayleigh wave based on the set detection depth range;

[0012] The acceleration detection module includes a plurality of acceleration sensors, which are used to arrange the acceleration sensors on the surface of the rock and soil area to be detected. The spacing between the acceleration sensors is determined based on the obtained Rayleigh wave wavelength, and the midpoint of the line connecting two adjacent acceleration sensors is marked as the excitation point.

[0013] The excitation waveform generation module is used to apply Rayleigh waves of a specific wavelength at the excitation point, record the acceleration time series data monitored by each acceleration sensor, generate raw waveform data based on the acceleration time series data, perform Fourier transform on the raw waveform data, extract the frequency data corresponding to each excitation, and obtain the Rayleigh wave velocity based on the frequency data analysis;

[0014] The dispersion curve analysis module is used to obtain a dispersion curve that is consistent with the Rayleigh wave dispersion characteristics based on the excitation frequency data and the corresponding Rayleigh wave velocity data. The obtained dispersion curve is used to identify the first inflection point where the Rayleigh wave velocity difference appears in a zigzag shape;

[0015] The frozen wall buried depth confirmation module is used to obtain the Rayleigh wave velocity of the inflection point position from the image based on the position of the inflection point in the dispersion curve diagram, and calculate the actual value of the frozen wall buried depth according to the inflection point occurrence time and the Rayleigh wave velocity at the inflection point position.

[0016] Furthermore, the range of the detection depth of the rock and soil area to be detected is set, wherein the minimum value of the detection depth is determined to be The maximum detection depth is , based on the set detection depth range, the formula for calculating the required Rayleigh wave wavelength is:

[0017]

[0018] Where, is the maximum wavelength of the desired Rayleigh wave, is the wavelength-to-depth conversion coefficient, where the wavelength of the Rayleigh wave is set according to the maximum depth required for detection, so as to detect the rock and soil in the entire detection depth range.

[0019] Furthermore, based on the obtained Rayleigh wave wavelength, the specific steps of determining the arrangement spacing between the acceleration sensors include:

[0020] The arrangement spacing range between the acceleration sensors is determined based on the obtained Rayleigh wave wavelength. The arrangement spacing range between the acceleration sensors is based on the formula:

[0021]

[0022] Where, The spacing between adjacent acceleration sensors is randomly selected from the spacing range as the spacing. Acceleration sensors are arranged based on the determined spacing, and the midpoint of the line connecting two adjacent acceleration sensors is marked as the excitation point. At this time, the distance between each adjacent excitation point is consistent with the arrangement distance between adjacent acceleration sensors, and the same is .

[0023] Furthermore, at each excitation point A specific wavelength of Rayleigh wave is continuously applied at the position, and the acceleration time series data detected by each acceleration sensor is recorded, where the specific wavelength is the maximum wavelength of the Rayleigh wave calculated. , continuously increase the frequency of the Rayleigh wave, record the Rayleigh wave acceleration time series data detected by each acceleration sensor, and generate original waveform data based on the Rayleigh wave acceleration time series data. The original waveform data has the horizontal axis as time t and the vertical axis as Rayleigh wave acceleration Waveform image data;

[0024] The formula for Fourier transform of original waveform data is:

[0025]

[0026] Where, is the Rayleigh wave acceleration The frequency domain signal obtained after Fourier transform is is the frequency of the applied Rayleigh wave, It is an imaginary unit used to represent phase information.

[0027] Furthermore, from the Fourier transform results The main frequency components are extracted, and the Rayleigh wave velocity is obtained according to the frequency data corresponding to each excitation. The formula for calculating the Rayleigh wave velocity is:

[0028]

[0029] Where, Indicates the frequency The Rayleigh wave velocity under is the phase difference between the signals received by adjacent acceleration sensors, is the distance between adjacent excitation points.

[0030] Furthermore, based on the frequency data of the excitation and the corresponding Rayleigh wave velocity data, a dispersion curve diagram consistent with the Rayleigh wave dispersion characteristics is obtained, wherein the horizontal coordinate of the dispersion curve diagram is the frequency data of the excitation, and the vertical coordinate is the corresponding Rayleigh wave velocity data. The dispersion curve diagram is drawn, and the first inflection point position where the Rayleigh wave velocity difference appears in a zigzag shape is confirmed. The Rayleigh wave velocity at the inflection point and the position before the inflection point is obtained from the image, and the wave velocity time series data during the Rayleigh wave application process is obtained at the same time; based on the wave velocity time series data from the start of the excitation to the position of the Rayleigh wave velocity inflection point, the actual value of the frozen wall buried depth is calculated, wherein the formula for calculating the actual value of the frozen wall buried depth is based on:

[0031]

[0032] Where, Indicates the actual value of the frozen wall depth at time t, is the time corresponding to the inflection point of the Rayleigh wave velocity difference, is the Rayleigh wave velocity corresponding to time t.

[0033] The present invention also provides a method for monitoring the development of an artificial frozen soil wall based on Rayleigh waves. The method is used to control the above-mentioned artificial frozen soil wall development monitoring system based on Rayleigh waves. The specific steps include:

[0034] Determine a rock and soil area to be detected, set a detection depth range for the rock and soil area to be detected, and calculate the wavelength of the required Rayleigh wave based on the set detection depth range;

[0035] On the surface of the rock mass to be tested, several acceleration sensors are placed. Based on the obtained Rayleigh wave wavelength, the spacing between the acceleration sensors is determined. The midpoint of the line connecting two adjacent acceleration sensors is marked as the excitation point.

[0036] Apply a Rayleigh wave of a specific wavelength at the excitation point, record the acceleration time series data monitored by each acceleration sensor, generate raw waveform data based on the acceleration time series data, perform Fourier transform on the raw waveform data, extract the frequency data corresponding to each excitation, and obtain the Rayleigh wave velocity based on the frequency data analysis;

[0037] Based on the excitation frequency data and the corresponding Rayleigh wave velocity data, a dispersion curve consistent with the Rayleigh wave dispersion characteristics was obtained. The obtained dispersion curve confirmed the location of the first inflection point where the Rayleigh wave velocity difference showed a zigzag shape.

[0038] Based on the position of the inflection point in the dispersion curve diagram, the Rayleigh wave velocity at the inflection point position is obtained from the image, and the actual value of the frozen wall buried depth is calculated according to the inflection point occurrence time and the Rayleigh wave velocity at the inflection point position.

[0039] Compared with the prior art, the present invention has the following beneficial effects:

[0040] In this solution, the layout spacing parameters can be accurately obtained during the preparatory test; the propagation parameters of Rayleigh waves in the soil during excitation can be obtained more accurately and in real time, and the irregular original waveform data can be converted into a Rayleigh wave dispersion curve through Fourier transform and empirical formula processing. The dispersion characteristics of Rayleigh waves can be used to conveniently obtain the location of frozen wall formation. This artificial freezing method for monitoring the formation and development of frozen walls does not require burying temperature sensors near the freezing pipes in the freezing construction area, achieving a more convenient and rapid method for monitoring the formation and development of frozen walls. The location of frozen wall appearance can be obtained through direct monitoring, without the need to infer the development of frozen walls through temperature sensors, directly and effectively avoiding the errors caused by inferring frozen wall formation through temperature monitoring. At the same time, it will not cause disturbance or damage to the structural rock and soil, and can achieve non-destructive and accurate monitoring of the location of frozen wall appearance. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 Schematic diagram of the overall system structure of the present invention;

[0042] Figure 2 This is a schematic diagram of the dispersion curve for monitoring the freezing period of the present invention;

[0043] Figure 3 Schematic diagram of the overall method of the present invention. DETAILED DESCRIPTION

[0044] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to specific embodiments.

[0045] It should be noted that, unless otherwise defined, the technical or scientific terms used in the present invention should have the usual meanings understood by people with ordinary skills in the field to which the present invention belongs. The "first", "second" and similar words used in the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. "Include" or "comprise" and similar words mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connect" or "connected" and similar words are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative position relationships. When the absolute position of the object being described changes, the relative position relationship may also change accordingly.

[0046] Example:

[0047] See also Figure 1-Figure 2 , the present invention provides a monitoring system:

[0048] A Rayleigh wave-based monitoring system for the development of artificial frozen soil and frozen walls, specifically comprising:

[0049] A Rayleigh wave wavelength analysis module is used to determine the rock and soil area to be detected, set the detection depth range of the rock and soil area to be detected, and calculate the wavelength of the required Rayleigh wave based on the set detection depth range;

[0050] Set the range of the detection depth of the rock and soil area to be detected, where the minimum value of the detection depth is determined to be The maximum detection depth is , based on the set detection depth range, the formula for calculating the required Rayleigh wave wavelength is:

[0051]

[0052] Where, is the maximum wavelength of the desired Rayleigh wave, is the wavelength-depth conversion coefficient, where the wavelength of the Rayleigh wave is set at the maximum depth required for detection, so as to detect the rock and soil in the entire detection depth range. The method of determining is: the penetration depth of the Rayleigh wave is within half the wavelength range, then .

[0053] The acceleration detection module includes a plurality of acceleration sensors, which are used to arrange the acceleration sensors on the surface of the rock and soil area to be detected. The spacing between the acceleration sensors is determined based on the obtained Rayleigh wave wavelength, and the midpoint of the line connecting two adjacent acceleration sensors is marked as the excitation point.

[0054] The specific steps of determining the arrangement spacing between the acceleration sensors based on the obtained Rayleigh wave wavelength include:

[0055] The arrangement spacing range between the acceleration sensors is determined based on the obtained Rayleigh wave wavelength. The arrangement spacing range between the acceleration sensors is based on the formula:

[0056]

[0057] Where, The spacing between adjacent acceleration sensors is randomly selected from the spacing range as the spacing. Acceleration sensors are arranged based on the determined spacing, and the midpoint of the line connecting two adjacent acceleration sensors is marked as the excitation point. At this time, the distance between each adjacent excitation point is consistent with the arrangement distance between adjacent acceleration sensors, and the same is .

[0058] Among them, when in use, the acceleration sensor can sense the propagation state of Rayleigh waves in the soil during excitation. In the accelerated state, by measuring the inertial force exerted on a miniature metal block inside the acceleration sensor, the acceleration value can be calculated using Newton's second law.

[0059] By calculating the accuracy of the distance between the sensor and the excitation point corresponding to the required measurement depth, the interference of various abnormal situations (including differences caused by different users and different monitoring depths) on the calculation of the distance between the sensor and the excitation point is reduced, thereby improving the reliability of the entire detection method. It can provide numerical calculations for monitoring the formation and development of frozen walls in a more objective and realistic manner, avoiding the situation where the monitoring depth is inaccurate and the monitoring data is inaccurate due to the layout of the equipment, so as to obtain more accurate data and achieve better monitoring results.

[0060] The excitation waveform generation module is used to apply Rayleigh waves of a specific wavelength at the excitation point, record the acceleration time series data monitored by each acceleration sensor, generate raw waveform data based on the acceleration time series data, perform Fourier transform on the raw waveform data, extract the frequency data corresponding to each excitation, and obtain the Rayleigh wave velocity based on the frequency data analysis;

[0061] At each excitation point A specific wavelength of Rayleigh wave is continuously applied at the position, and the acceleration time series data detected by each acceleration sensor is recorded, where the specific wavelength is the maximum wavelength of the Rayleigh wave calculated. , continuously increase the frequency of the Rayleigh wave, record the Rayleigh wave acceleration time series data detected by each acceleration sensor, and generate original waveform data based on the Rayleigh wave acceleration time series data. The original waveform data has the horizontal axis as time t and the vertical axis as Rayleigh wave acceleration Waveform image data;

[0062] The formula for Fourier transform of original waveform data is:

[0063]

[0064] Where, is the Rayleigh wave acceleration The frequency domain signal obtained after Fourier transform is is the frequency of the applied Rayleigh wave, It is an imaginary unit used to represent phase information.

[0065] From the Fourier transform results, the magnitude spectrum can be calculated to identify the frequency components, where the magnitude spectrum can be calculated by the following formula:

[0066]

[0067] Where, represents the magnitude spectrum, Represents frequency domain signal The real part of Represents frequency domain signal In order to improve the accuracy of extraction, a threshold can be set. Only frequency components in the amplitude spectrum that are greater than the threshold are considered significant, which helps to filter out noise and weak signals.

[0068] From the Fourier transform results The frequency component is extracted from the equation, and the Rayleigh wave velocity is obtained based on the frequency data corresponding to each excitation. The formula for calculating the Rayleigh wave velocity is:

[0069]

[0070] Where, Indicates the frequency The Rayleigh wave velocity under is the phase difference between the signals received by adjacent acceleration sensors, is the distance between adjacent excitation points.

[0071] The dispersion curve analysis module is used to obtain a dispersion curve that is consistent with the Rayleigh wave dispersion characteristics based on the excitation frequency data and the corresponding Rayleigh wave velocity data. The obtained dispersion curve is used to identify the first inflection point where the Rayleigh wave velocity difference appears in a zigzag shape;

[0072] The zigzag inflection point in the dispersion curve is where the Rayleigh wave velocity experiences a significant inflection point when propagating through unfrozen soil to frozen soil. This change can be used to infer the location of the frozen wall, i.e., the location where the frozen wall is formed. The propagation characteristics of Rayleigh waves in the medium can be used to monitor the freeze-thaw cycle of the soil during the artificial freezing construction, and to monitor the appearance and range of the frozen wall. Generally, when the soil frost heave cycles, the periphery of the frozen wall is unfrozen ordinary soil. Since the characteristics of the soil after freezing are significantly different from those of ordinary soil, the Rayleigh wave velocity between the two materials will show a significant mutation. The wave velocity undergoes a large zigzag change when passing through the frozen wall, and the location of the frozen wall can be clearly recorded. Based on the excited frequency data and the corresponding Rayleigh wave velocity data, a dispersion curve diagram that is consistent with the Rayleigh wave dispersion characteristics is obtained. The horizontal axis of the dispersion curve diagram is the excited frequency data, and the vertical axis is the corresponding Rayleigh wave velocity data. The dispersion curve diagram is drawn. For specific dispersion curve diagrams, please refer to Figure 2 .

[0073] The frozen wall buried depth confirmation module is used to obtain the Rayleigh wave velocity of the inflection point position from the image based on the position of the inflection point in the dispersion curve diagram, and calculate the actual value of the frozen wall buried depth according to the inflection point occurrence time and the Rayleigh wave velocity at the inflection point position.

[0074] The first inflection point where the Rayleigh wave velocity difference appears in a zigzag pattern is identified, and the Rayleigh wave velocity at the inflection point and the position before the inflection point is obtained from the image. The velocity time series data during the Rayleigh wave application process is also obtained. The actual frozen wall depth is calculated based on the velocity time series data from the start of excitation to the Rayleigh wave velocity inflection point. The formula for calculating the actual frozen wall depth is:

[0075]

[0076] Where, Indicates the actual value of the frozen wall depth at time t, is the time corresponding to the inflection point of the Rayleigh wave velocity difference, is the Rayleigh wave velocity corresponding to time t.

[0077] See also Figure 3 The present invention also provides a method for monitoring the development process of an artificial frozen soil wall based on Rayleigh waves. The method is used to control the above-mentioned artificial frozen soil wall development process monitoring system based on Rayleigh waves. The specific steps include:

[0078] Step 1: Determine the rock and soil area to be detected, set the detection depth range of the rock and soil area to be detected, and calculate the wavelength of the required Rayleigh wave based on the set detection depth range;

[0079] Step 2: Deploy several acceleration sensors on the surface of the rock mass to be tested. Based on the obtained Rayleigh wave wavelength, determine the spacing between the acceleration sensors. Mark the midpoint of the line connecting two adjacent acceleration sensors as the excitation point.

[0080] Step 3: Apply a Rayleigh wave of a specific wavelength at the excitation point, record the acceleration time series data detected by each accelerometer, generate raw waveform data based on the acceleration time series data, perform Fourier transform on the raw waveform data, extract the frequency data corresponding to each excitation, and obtain the Rayleigh wave velocity based on the frequency data analysis;

[0081] Step 4: Based on the excitation frequency data and the corresponding Rayleigh wave velocity data, a dispersion curve is obtained that matches the Rayleigh wave dispersion characteristics. The obtained dispersion curve is used to identify the first inflection point where the Rayleigh wave velocity difference appears in a zigzag pattern.

[0082] Step 5: Based on the position of the inflection point in the dispersion curve diagram, the Rayleigh wave velocity at the inflection point position is obtained from the image, and the actual value of the frozen wall burial depth is calculated according to the inflection point occurrence time and the Rayleigh wave velocity at the inflection point position.

[0083] The above formulas are all dimensionless and numerical calculations. The formulas are obtained by collecting a large amount of data and performing software simulation to obtain the most recent real situation. The preset parameters in the formulas are set by technicians in this field according to actual conditions.

[0084] The above embodiments can be implemented in whole or in part by software, hardware, firmware, or any other combination thereof. When implemented using software, the above embodiments can be implemented in whole or in part in the form of a computer program product. Those skilled in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented by electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed by hardware or software depends on the specific application and design constraints of the technical solution.

[0085] The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, and may be located in one place or distributed across multiple network units. Some or all of these units may be selected to achieve the purpose of this embodiment as needed.

[0086] The above is only a specific implementation method of the present application, but the scope of protection of the present application is not limited thereto. Any technician familiar with this technical field can easily think of changes or replacements within the technical scope disclosed in this application, which should be covered by the scope of protection of the present application.

Claims

1. A system for monitoring the development of artificial frozen soil and frozen wall based on Rayleigh waves, characterized in that: Specifically include: A Rayleigh wave wavelength analysis module is used to determine the rock and soil area to be detected, set the detection depth range of the rock and soil area to be detected, and calculate the wavelength of the required Rayleigh wave based on the set detection depth range; The acceleration detection module includes a plurality of acceleration sensors, which are used to arrange the acceleration sensors on the surface of the rock and soil area to be detected. The spacing between the acceleration sensors is determined based on the obtained Rayleigh wave wavelength, and the midpoint of the line connecting two adjacent acceleration sensors is marked as the excitation point. The excitation waveform generation module is used to apply Rayleigh waves of a specific wavelength at the excitation point, record the acceleration time series data monitored by each acceleration sensor, generate raw waveform data based on the acceleration time series data, perform Fourier transform on the raw waveform data, extract the frequency data corresponding to each excitation, and obtain the Rayleigh wave velocity based on the frequency data analysis; The dispersion curve analysis module is used to obtain a dispersion curve that matches the Rayleigh wave dispersion characteristics based on the excitation frequency data and the corresponding Rayleigh wave velocity data. The obtained dispersion curve is used to identify the first inflection point where the Rayleigh wave velocity difference appears in a zigzag shape. A frozen wall depth confirmation module is used to obtain the Rayleigh wave velocity at the inflection point position from the image based on the position of the inflection point in the dispersion curve diagram, and calculate the actual value of the frozen wall depth according to the inflection point occurrence time and the Rayleigh wave velocity at the inflection point position; The dispersion curve is plotted with the excitation frequency data on the horizontal axis and the corresponding Rayleigh wave velocity data on the vertical axis. The dispersion curve is plotted to identify the first inflection point where the Rayleigh wave velocity difference appears in a zigzag pattern. The Rayleigh wave velocities at the inflection point and before the inflection point are obtained from the image. The velocity time series data during the Rayleigh wave application process is also obtained. The actual value of the frozen wall burial depth is calculated based on the wave velocity time series data from the start of excitation to the inflection point of the Rayleigh wave velocity. The formula for calculating the actual value of the frozen wall burial depth is: Where, Indicates the actual value of the frozen wall depth at time t, is the time corresponding to the inflection point of the Rayleigh wave velocity difference, is the Rayleigh wave velocity corresponding to time t.

2. The artificial frozen soil frozen wall development process monitoring system based on Rayleigh waves according to claim 1 is characterized by: Set the range of the detection depth of the rock and soil area to be detected, where the minimum value of the detection depth is determined to be The maximum detection depth is , based on the set detection depth range, the formula for calculating the required Rayleigh wave wavelength is: Where, is the maximum wavelength of the desired Rayleigh wave, is the wavelength-to-depth conversion coefficient, where the wavelength of the Rayleigh wave is set according to the maximum depth required for detection, so as to detect the rock and soil in the entire detection depth range.

3. The artificial frozen soil frozen wall development process monitoring system based on Rayleigh waves according to claim 2 is characterized by: The specific steps of determining the arrangement spacing between the acceleration sensors based on the obtained Rayleigh wave wavelength include: The arrangement spacing range between the acceleration sensors is determined based on the obtained Rayleigh wave wavelength. The arrangement spacing range between the acceleration sensors is based on the formula: Where, The spacing between adjacent acceleration sensors is randomly selected from the spacing range as the spacing. Acceleration sensors are arranged based on the determined spacing, and the midpoint of the line connecting two adjacent acceleration sensors is marked as the excitation point. At this time, the distance between each adjacent excitation point is consistent with the arrangement distance between adjacent acceleration sensors, and the same is .

4. The artificial frozen soil frozen wall development process monitoring system based on Rayleigh waves according to claim 2 is characterized by: At each excitation point A specific wavelength of Rayleigh wave is continuously applied at the position, and the acceleration time series data detected by each acceleration sensor is recorded, where the specific wavelength is the maximum wavelength of the Rayleigh wave calculated. , continuously increase the frequency of the Rayleigh wave, record the Rayleigh wave acceleration time series data detected by each acceleration sensor, and generate original waveform data based on the Rayleigh wave acceleration time series data. The original waveform data has the horizontal axis as time t and the vertical axis as Rayleigh wave acceleration Waveform image data; The formula for Fourier transform of original waveform data is: Where, is the Rayleigh wave acceleration The frequency domain signal obtained after Fourier transform is is the frequency of the applied Rayleigh wave, It is an imaginary unit used to represent phase information.

5. The artificial frozen soil frozen wall development process monitoring system based on Rayleigh waves according to claim 4 is characterized in that: From the Fourier transform results The frequency component is extracted from the equation, and the Rayleigh wave velocity is obtained based on the frequency data corresponding to each excitation. The formula for calculating the Rayleigh wave velocity is: Where, Indicates the frequency The Rayleigh wave velocity under is the phase difference between the signals received by adjacent acceleration sensors, is the distance between adjacent excitation points.

6. A method for monitoring the development of artificial frozen soil walls based on Rayleigh waves, characterized by: The Rayleigh wave-based artificial frozen soil frozen wall development process monitoring method is used to control the Rayleigh wave-based artificial frozen soil frozen wall development process monitoring system according to any one of claims 1 to 5, and the specific steps include: Determine a rock and soil area to be detected, set a detection depth range for the rock and soil area to be detected, and calculate the wavelength of the required Rayleigh wave based on the set detection depth range; On the surface of the rock mass to be tested, several acceleration sensors are placed. Based on the obtained Rayleigh wave wavelength, the spacing between the acceleration sensors is determined. The midpoint of the line connecting two adjacent acceleration sensors is marked as the excitation point. Apply a Rayleigh wave of a specific wavelength at the excitation point, record the acceleration time series data monitored by each acceleration sensor, generate raw waveform data based on the acceleration time series data, perform Fourier transform on the raw waveform data, extract the frequency data corresponding to each excitation, and obtain the Rayleigh wave velocity based on the frequency data analysis; Based on the excitation frequency data and the corresponding Rayleigh wave velocity data, a dispersion curve consistent with the Rayleigh wave dispersion characteristics was obtained. The obtained dispersion curve confirmed the location of the first inflection point where the Rayleigh wave velocity difference showed a zigzag shape. Based on the position of the inflection point in the dispersion curve diagram, the Rayleigh wave velocity at the inflection point position is obtained from the image, and the actual value of the frozen wall buried depth is calculated according to the inflection point occurrence time and the Rayleigh wave velocity at the inflection point position.

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