Rayleigh wave-based artificial frozen soil frozen wall development process monitoring system and method

Abstract

The invention discloses an artificial frozen soil frozen wall development process monitoring system and method based on Rayleigh waves, and relates to the field of sound wave detection. Comprising the following steps: calculating the wavelength of a required Rayleigh wave based on the range of frozen wall detection depth required by a monitoring project; arranging a plurality of acceleration sensors on the surface of the to-be-detected rock-soil body area, determining the arrangement distance of each acceleration sensor based on the obtained Rayleigh wave wavelength, and marking the midpoint of the connecting line of the adjacent acceleration sensors as an excitation point; applying a Rayleigh wave with a specific wavelength at an excitation point, collecting original waveform data, extracting corresponding frequency data, and obtaining a Rayleigh wave velocity map through Fourier transform; based on the excited frequency data and the Rayleigh wave velocity, a frequency dispersion curve graph is obtained, and the position of a first inflection point where the Rayleigh wave velocity difference appears in a zigzag shape in the graph is determined; and obtaining the wave velocity of the inflection point position from the image, and calculating the actual buried depth value of the frozen wall according to the occurrence time of the inflection point and the Rayleigh wave velocity of the inflection point position.

Description

Technical Field

[0001] The invention relates to the technical field of acoustic wave detection, and in particular to a system and method for monitoring the development process of an 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 high-pressure water strata to ensure stability and safety during tunnel construction. It was first used as a temporary support method. The researchers discussed various factors that affect the selection of freezing temperature, freezing zone thickness and freezing pipe spacing, providing a new direction for the application of artificial freezing method.

[0003] However, when artificial freezing technology is used, soil expansion or other problems during the freezing and thawing process can seriously affect the construction process and lead to serious accidents. Therefore, it is very important to monitor the freezing and thawing of the soil and the development of the frozen wall during the freezing construction process. Generally, researchers insert temperature sensors into the frozen soil to obtain the soil freezing temperature and conduct numerical simulation analysis to study the changes of the soil during the freezing and thawing process.

[0004] Rayleigh waves are the result of the interference of longitudinal and transverse waves, and are usually characterized by relatively low speed, low frequency, and high amplitude. Rayleigh wave survey technology is a low-cost, high-efficiency, and high-precision non-destructive testing technology. In the detection technology using Rayleigh waves, the variation of shear velocity with depth can be evaluated based on the dispersion characteristics of Rayleigh waves, so the soil conditions at different depths of the soil layer can be monitored based on the variation of wave velocity at different depths.

[0005] Therefore, due to the dispersion characteristics of Rayleigh waves, a large change in wave velocity will occur in frozen soil and non-frozen soil. Based on this fact, the detection equipment can detect the development of frozen walls during freezing and verify the applicability of non-destructive testing technology based on Rayleigh wave method in artificial freezing detection. More importantly, the theory and experiment proposed in this study can provide valuable reference for the application of Rayleigh wave detection technology in the field monitoring of soil freeze-thaw development in artificial freezing construction in the future.

[0006] In the prior art, the publication number CN108468321A discloses a method for ultrasonic monitoring of frozen wall development, which includes the following steps: when the frozen wall is not formed, monitoring holes are arranged around the wellbore according to geological conditions, and the depth of the monitoring holes is generally 1.2 times the required freezing depth. Two ultrasonic integrators are arranged in the same horizontal plane inside the conduit through the reserved holes at a certain vertical spacing, and the ultrasonic integrators are used to receive and transmit ultrasonic waves. When the ultrasonic integrator is completely placed, the reserved holes are sealed on the outside with tape; the integrator placed in the conduit transmits the signal to the computer through the wire, and the computer data processing system is used to process the data to obtain the change curve of the ultrasonic wave velocity, and the frozen wall development is analyzed. However, in this method, the propagation of ultrasonic waves in the material will be attenuated, especially in soil or rock and other media, which may cause the signal to weaken, affecting the accuracy and reliability of the data. At the same time, the design depth and layout of the monitoring holes may be limited, and all important areas of the frozen wall cannot be covered, which may lead to 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 constitute the prior art that is already known to one 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 frozen wall based on Rayleigh waves, so as to solve the problems raised in the above-mentioned background technology.

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

[0010] A monitoring system for the development process of artificial frozen soil freezing wall based on Rayleigh waves, 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 a plurality of acceleration sensors on the surface of the rock and soil area to be detected, determine the arrangement spacing between the acceleration sensors based on the obtained Rayleigh wave wavelength, and mark the midpoint of the line connecting two adjacent acceleration sensors 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 original waveform data according to the acceleration time series data, perform Fourier transform on the original 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 diagram that is consistent with the dispersion characteristics of the Rayleigh wave based on the frequency data of the excitation and the corresponding Rayleigh wave velocity data. The dispersion curve diagram obtained is used to confirm the first inflection point position 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 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 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 H min The maximum detection depth is H max , based on the set detection depth range, the formula for calculating the wavelength of the required Rayleigh wave is:

[0017]

[0018] In the formula, λ Rmax is the maximum wavelength of the required Rayleigh wave, and β is the wavelength-to-depth conversion coefficient, wherein the wavelength of the Rayleigh wave is set according to the maximum depth required for detection, so as to detect the rock and soil body 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, and the arrangement spacing range between the acceleration sensors is based on the formula:

[0021]

[0022] In the formula, Δx is the arrangement spacing between adjacent acceleration sensors. A value is randomly selected from the arrangement spacing range as the arrangement spacing. Acceleration sensors are arranged based on the determined arrangement spacing. The midpoint of the line connecting two adjacent acceleration sensors is marked and recorded as the excitation point D. P At this time, the distance between each adjacent excitation point is consistent with the arrangement distance between adjacent acceleration sensors, which is also Δx.

[0023] Furthermore, at each excitation point D P A Rayleigh wave of a specific wavelength is continuously applied at the position, and the acceleration time series data monitored by each acceleration sensor is recorded, wherein the specific wavelength is the maximum wavelength λ of the Rayleigh wave calculated Rmax, continuously increasing the frequency of applying Rayleigh waves, recording the Rayleigh wave acceleration time series data monitored by each acceleration sensor, and generating original waveform data based on the Rayleigh wave acceleration time series data, wherein the original waveform data is waveform image data with the horizontal coordinate being time t and the vertical coordinate being the Rayleigh wave acceleration α(t);

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

[0025]

[0026] Where α(f) is the frequency domain signal obtained after Fourier transform of the Rayleigh wave acceleration α(t), f is the frequency of the applied Rayleigh wave, and j is an imaginary unit used to represent the phase information.

[0027] Furthermore, the main frequency components are extracted from the Fourier transform result α(f), 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 V R (f) represents the Rayleigh wave velocity at frequency f, is the phase velocity, Δx is the distance between adjacent excitation points; where the phase velocity The calculation is based on the formula:

[0030]

[0031] In the formula, k is the wave number, and the specific calculation formula of the wave number k is:

[0032]

[0033] Further, 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 abscissa of the dispersion curve diagram is the frequency data of the excitation, and the ordinate is the corresponding Rayleigh wave velocity data, a dispersion curve diagram is drawn, 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; based on the wave velocity time series data from the start of applying the excitation to the Rayleigh wave velocity inflection point position, 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 as follows:

[0034]

[0035] Where S(t) represents the actual value of the frozen wall depth at time t, gV is the time corresponding to the inflection point of the Rayleigh wave velocity difference, R (t) is the Rayleigh wave velocity corresponding to time t.

[0036] The present invention also provides a method for monitoring the development process of an artificial frozen soil frozen wall based on Rayleigh waves. The method for monitoring the development process of an artificial frozen soil frozen wall based on Rayleigh waves is used to control the above-mentioned artificial frozen soil frozen wall development process monitoring system based on Rayleigh waves. The specific steps include:

[0037] Determine a rock and soil area to be detected, set a 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;

[0038] On the surface of the rock and soil area to be detected, a number of acceleration sensors are arranged, and the arrangement 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;

[0039] Apply a Rayleigh wave of a specific wavelength at the excitation point, record the acceleration time series data monitored by each acceleration sensor, generate original waveform data based on the acceleration time series data, perform Fourier transform on the original waveform data, extract the frequency data corresponding to each excitation, and obtain the Rayleigh wave velocity based on the frequency data analysis;

[0040] 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. Through the obtained dispersion curve diagram, the first inflection point position where the Rayleigh wave velocity difference appears in a zigzag shape is confirmed;

[0041] 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.

[0042] Compared with the prior art, the present invention has the following beneficial effects:

[0043] In this scheme, 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 Rayleigh wave dispersion curves through Fourier transform and empirical formula processing, and the formation position of the frozen wall can be conveniently obtained by using the dispersion characteristics of Rayleigh waves. The 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, and realizes a more convenient and quick method for monitoring the formation and development of frozen walls. The position of the frozen wall can be obtained through direct monitoring, and there is no need to infer the development of the frozen wall through temperature sensors, which directly and effectively avoids the errors caused by inferring the formation of frozen walls using 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 position of the frozen wall. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 It is a schematic diagram of the overall system structure of the present invention;

[0045] Figure 2 This is a schematic diagram of the monitoring dispersion curve during the freezing period of the present invention;

[0046] Figure 3 It is a schematic diagram of the overall method flow of the present invention. DETAILED DESCRIPTION

[0047] 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 in conjunction with specific embodiments.

[0048] It should be noted that, unless otherwise defined, the technical terms or scientific terms used in the present invention should be understood by people with ordinary skills in the field to which the present invention belongs. The words "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 positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0049] Example:

[0050] See also Figure 1-Figure 2 , the present invention provides a monitoring system:

[0051] A monitoring system for the development process of artificial frozen soil freezing wall based on Rayleigh waves, specifically comprising:

[0052] 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;

[0053] Set the range of detection depth of the rock and soil area to be detected, where the minimum detection depth is determined to be H min The maximum detection depth is H max , based on the set detection depth range, the formula for calculating the wavelength of the required Rayleigh wave is:

[0054]

[0055] In the formula, λ Rmax is the maximum wavelength of the required Rayleigh wave, and β 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 body in the entire detection depth range. The wavelength-to-depth conversion coefficient β is determined as follows: the penetration depth of the Rayleigh wave is currently within the half wavelength range, then β = 0.5.

[0056] The acceleration detection module includes a plurality of acceleration sensors, which are used to arrange a plurality of acceleration sensors on the surface of the rock and soil area to be detected, determine the arrangement spacing between the acceleration sensors based on the obtained Rayleigh wave wavelength, and mark the midpoint of the line connecting two adjacent acceleration sensors as the excitation point;

[0057] Based on the obtained Rayleigh wave wavelength, the specific steps of determining the arrangement spacing between the acceleration sensors include:

[0058] The arrangement spacing range between the acceleration sensors is determined based on the obtained Rayleigh wave wavelength, and the arrangement spacing range between the acceleration sensors is based on the formula:

[0059]

[0060] In the formula, Δx is the arrangement spacing between adjacent acceleration sensors. A value is randomly selected from the arrangement spacing range as the arrangement spacing. Acceleration sensors are arranged based on the determined arrangement spacing. The midpoint of the line connecting two adjacent acceleration sensors is marked and recorded as the excitation point D. P At this time, the distance between each adjacent excitation point is consistent with the arrangement distance between adjacent acceleration sensors, which is also Δx.

[0061] When in use, the acceleration sensor can sense the propagation state of Rayleigh waves in the soil during excitation. In the accelerated state, the acceleration value can be calculated using Newton's second law by measuring the inertial force exerted on a micro metal block inside the acceleration sensor.

[0062] By calculating the accuracy of the distance between the sensor and the excitation point corresponding to the required measuring 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 more objectively and realistically, avoiding inaccurate monitoring depth and inaccurate monitoring data due to equipment layout, so as to obtain more accurate data and achieve better monitoring effects.

[0063] 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 original waveform data according to the acceleration time series data, perform Fourier transform on the original waveform data, extract the frequency data corresponding to each excitation, and obtain the Rayleigh wave velocity based on the frequency data analysis;

[0064] At each excitation point D P A Rayleigh wave of a specific wavelength is continuously applied at the position, and the acceleration time series data monitored by each acceleration sensor is recorded, wherein the specific wavelength is the maximum wavelength λ of the Rayleigh wave calculated Rmax , continuously increasing the frequency of applying Rayleigh waves, recording the Rayleigh wave acceleration time series data monitored by each acceleration sensor, and generating original waveform data based on the Rayleigh wave acceleration time series data, wherein the original waveform data is waveform image data with the horizontal coordinate being time t and the vertical coordinate being the Rayleigh wave acceleration α(t);

[0065] The formula for Fourier transform of original waveform data is:

[0066]

[0067] Where α(f) is the frequency domain signal obtained after Fourier transform of the Rayleigh wave acceleration α(t), f is the frequency of the applied Rayleigh wave, and j is an imaginary unit used to represent the phase information.

[0068] From the Fourier transform result, the magnitude spectrum can be calculated to identify the frequency components, where the magnitude spectrum can be calculated by the following formula:

[0069]

[0070] In the formula, |α(f)| represents the amplitude spectrum, Re{α(f)} represents the real part of the frequency domain signal α(f), and Im{α(f)} represents the imaginary part of the frequency domain signal α(f). In order to improve the accuracy of extraction, a threshold can be set. Only frequency components in the amplitude spectrum greater than the threshold are considered significant, which helps to filter out noise and weak signals.

[0071] The frequency component is extracted from the Fourier transform result α(f), 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:

[0072]

[0073] Where V R (f) represents the Rayleigh wave velocity at frequency f, is the phase velocity, Δx is the distance between adjacent excitation points;

[0074] Among them, the phase velocity The calculation is based on the formula:

[0075]

[0076] In the formula, k is the wave number, and the specific calculation formula of the wave number k is:

[0077]

[0078] The dispersion curve analysis module is used to obtain a dispersion curve diagram that is consistent with the dispersion characteristics of the Rayleigh wave based on the frequency data of the excitation and the corresponding Rayleigh wave velocity data. The dispersion curve diagram obtained is used to confirm the first inflection point position where the Rayleigh wave velocity difference appears in a zigzag shape;

[0079] The zigzag inflection point in the dispersion curve is the location where the velocity of the Rayleigh wave will experience a significant velocity inflection when it propagates from the unfrozen soil to the frozen soil. The location where the frozen wall appears, that is, the location where the frozen wall is formed, can be inferred by monitoring this change. According to the propagation characteristics of Rayleigh waves in the medium, it can be used to monitor the freeze-thaw cycle of the soil during the freezing construction of the artificial freezing method, and to monitor the appearance and range of the frozen wall. In general, when the soil frost heaves and circles, the periphery of the frozen wall is the unfrozen ordinary soil. Since the characteristics of the soil after freezing are significantly different from those of the ordinary soil, the Rayleigh wave velocity between the two materials will show a significant mutation. When the wave velocity passes through the frozen wall, a large zigzag change occurs, and the location where the frozen wall appears 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 coordinate of the dispersion curve diagram is the excited frequency data, and the vertical coordinate is the corresponding Rayleigh wave velocity data. The dispersion curve diagram is drawn. For specific dispersion curve diagrams, please refer to Figure 2 .

[0080] The frozen wall buried 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 buried depth according to the inflection point occurrence time and the Rayleigh wave velocity at the inflection point position.

[0081] Confirm the first inflection point where the Rayleigh wave velocity difference appears in a zigzag shape, obtain the Rayleigh wave velocity at the inflection point and before the inflection point from the image, and simultaneously obtain the wave velocity time series data during the Rayleigh wave application process; calculate the actual value of the frozen wall buried depth based on the wave velocity time series data from the start of the excitation to the Rayleigh wave velocity inflection point, where the formula for calculating the actual value of the frozen wall buried depth is:

[0082]

[0083] Where S(t) represents the actual value of the frozen wall depth at time t, g V is the time corresponding to the inflection point of the Rayleigh wave velocity difference, R (t) is the Rayleigh wave velocity corresponding to time t.

[0084] See also Figure 3 The present invention also provides a method for monitoring the development process of artificial frozen soil frozen wall based on Rayleigh waves. The method for monitoring the development process of artificial frozen soil frozen wall based on Rayleigh waves is used to control the above-mentioned artificial frozen soil frozen wall development process monitoring system based on Rayleigh waves. The specific steps include:

[0085] 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;

[0086] Step 2: On the surface of the rock and soil area to be detected, a number of acceleration sensors are arranged. Based on the obtained Rayleigh wave wavelength, the arrangement spacing between the acceleration sensors is determined, and the midpoint of the line connecting two adjacent acceleration sensors is marked as the excitation point;

[0087] Step 3: Apply a Rayleigh wave of a specific wavelength at the excitation point, record the acceleration time series data monitored by each acceleration sensor, generate original waveform data based on the acceleration time series data, perform Fourier transform on the original waveform data, extract the frequency data corresponding to each excitation, and obtain the Rayleigh wave velocity based on the frequency data analysis;

[0088] Step 4: 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. Through the obtained dispersion curve diagram, the first inflection point position where the Rayleigh wave velocity difference appears in a zigzag shape is confirmed;

[0089] 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.

[0090] The above formulas are all dimensionless and numerical calculations. The formula is a formula for the most recent real situation obtained by collecting a large amount of data and performing software simulation. The preset parameters in the formula are set by technicians in this field according to actual conditions.

[0091] The above embodiments may be implemented in whole or in part by software, hardware, firmware or any other combination thereof. When implemented by software, the above embodiments may be implemented in whole or in part in the form of a computer program product. Those skilled in the art may appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein may be implemented by electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed by hardware or software methods depends on the specific application and design constraints of the technical solution.

[0092] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, and may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0093] The above description is only a specific implementation manner of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application.

Claims

1. A monitoring system for 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 a plurality of acceleration sensors on the surface of the rock and soil area to be detected, determine the arrangement spacing between the acceleration sensors based on the obtained Rayleigh wave wavelength, and mark the midpoint of the line connecting two adjacent acceleration sensors 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 original waveform data according to the acceleration time series data, perform Fourier transform on the original 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 diagram that is consistent with the dispersion characteristics of the Rayleigh wave based on the frequency data of the excitation and the corresponding Rayleigh wave velocity data. The dispersion curve diagram obtained is used to confirm the first inflection point position where the Rayleigh wave velocity difference appears in a zigzag shape; The frozen wall buried 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 buried depth according to the inflection point occurrence time and the Rayleigh wave velocity at the inflection point position.

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 detection depth of the rock and soil area to be detected, where the minimum detection depth is determined to be H min The maximum detection depth is H max , based on the set detection depth range, the formula for calculating the wavelength of the required Rayleigh wave is: In the formula, λ Rmax is the maximum wavelength of the required Rayleigh wave, and β is the wavelength-to-depth conversion coefficient, wherein the wavelength of the Rayleigh wave is set according to the maximum depth required for detection, so as to detect the rock and soil body 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 in that: Based on the obtained Rayleigh wave wavelength, the specific steps of determining the arrangement spacing between the acceleration sensors include: The arrangement spacing range between the acceleration sensors is determined based on the obtained Rayleigh wave wavelength, and the arrangement spacing range between the acceleration sensors is based on the formula: In the formula, Δx is the arrangement spacing between adjacent acceleration sensors. A value is randomly selected from the arrangement spacing range as the arrangement spacing. Acceleration sensors are arranged based on the determined arrangement spacing. The midpoint of the line connecting two adjacent acceleration sensors is marked and recorded as the excitation point D. P At this time, the distance between each adjacent excitation point is consistent with the arrangement distance between adjacent acceleration sensors, which is also Δx.

4. The artificial frozen soil frozen wall development process monitoring system based on Rayleigh waves according to claim 2 is characterized in that: At each excitation point D P A Rayleigh wave of a specific wavelength is continuously applied at the position, and the acceleration time series data monitored by each acceleration sensor is recorded, wherein the specific wavelength is the maximum wavelength λ of the Rayleigh wave calculated Rmax , continuously increasing the frequency of applying Rayleigh waves, recording the Rayleigh wave acceleration time series data monitored by each acceleration sensor, and generating original waveform data based on the Rayleigh wave acceleration time series data, wherein the original waveform data is waveform image data with the horizontal coordinate being time t and the vertical coordinate being the Rayleigh wave acceleration α(t); The formula for Fourier transform of original waveform data is: Where α(f) is the frequency domain signal obtained after Fourier transform of the Rayleigh wave acceleration α(t), f is the frequency of the applied Rayleigh wave, and j is an imaginary unit used to represent the 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: The frequency component is extracted from the Fourier transform result α(f), 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: Where V R (f) represents the Rayleigh wave velocity at frequency f, is the phase velocity, Δx is the distance between adjacent excitation points; Among them, the phase velocity The calculation is based on the formula: In the formula, k is the wave number, and the specific calculation formula of the wave number k is:

6. The artificial frozen soil frozen wall development process monitoring system based on Rayleigh waves according to claim 1 is characterized by: Based on the frequency data of the excitation and the corresponding Rayleigh wave velocity data, a dispersion curve diagram that is consistent with the Rayleigh wave dispersion characteristics is obtained, wherein the abscissa of the dispersion curve diagram is the frequency data of the excitation and the ordinate is the corresponding Rayleigh wave velocity data, a dispersion curve diagram is drawn, 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; Based on the wave velocity time series data from the start of excitation to the inflection point of the Rayleigh wave velocity, the actual value of the frozen wall burial depth is calculated, wherein the formula for calculating the actual value of the frozen wall burial depth is: Where S(t) represents the actual value of the frozen wall depth at time t, g V is the time corresponding to the inflection point of the Rayleigh wave velocity difference, R (t) is the Rayleigh wave velocity corresponding to time t.

7. A method for monitoring the development process of artificial frozen soil frozen wall based on Rayleigh waves, characterized in that: The artificial frozen soil frozen wall development process monitoring method based on Rayleigh waves is used to control the artificial frozen soil frozen wall development process monitoring method based on Rayleigh waves according to any one of claims 1 to 6, and the specific steps include: Determine a rock and soil area to be detected, set a 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; On the surface of the rock and soil area to be detected, a number of acceleration sensors are arranged, and the arrangement 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; Apply a Rayleigh wave of a specific wavelength at the excitation point, record the acceleration time series data monitored by each acceleration sensor, generate original waveform data based on the acceleration time series data, perform Fourier transform on the original 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 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. Through the obtained dispersion curve diagram, the first inflection point position of the zigzag Rayleigh wave velocity difference is confirmed; 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.

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