A method and system for online monitoring of water and salt migration in a salt-frozen soil roadbed
By combining the dynamic calibration of multi-frequency composite probes and dual-ring resistivity response with micro-enclosed cavity self-calibration technology, the problem of dynamic changes in salt discharge efficiency during the freezing process of permafrost was solved, realizing accurate monitoring and intelligent early warning of water and salt migration in saline permafrost roadbeds.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-06-03
- Publication Date
- 2026-07-21
AI Technical Summary
Existing technologies have failed to effectively address the water-salt coupling mechanism during the freezing of permafrost, resulting in the lack of dynamic monitoring of changes in salt discharge efficiency and the absence of real-time sensor calibration, which affects the accuracy of water-salt migration patterns and the stability of long-term monitoring.
A multi-frequency composite probe is used for structured data acquisition and preprocessing. The salt discharge coefficient is dynamically calibrated by combining the dual-ring resistivity response. Self-calibration is performed by the thermodynamic consistency between the reference solution of the micro-closed cavity and the freezing point of the soil. The water-salt state is inverted using a water-thermal-salt coupled migration model to generate a visualized cloud map and early warning information.
It enables precise perception and long-term stable monitoring of water and salt migration patterns within saline-frozen soil roadbeds, provides intelligent risk warnings, and improves the accuracy of water and salt migration monitoring and the real-time data calibration capability.
Smart Images
Figure CN122430404A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of monitoring technology for transportation infrastructure projects, and in particular to an online monitoring method and system for water and salt migration in saline-frozen soil roadbeds. Background Technology
[0002] The engineering properties of saline-frozen soils are significantly influenced by the coupling effects of water migration, salt crystallization, and phase transition processes. Currently, online monitoring of water and salt migration in roadbeds in cold-region engineering primarily relies on time-domain reflectometry and frequency-domain reflectometry combined with thermistor arrays to obtain data on soil moisture content, conductivity, and temperature field. With technological advancements, advanced techniques such as multi-frequency dielectric spectroscopy and resistivity tomography are also widely used, enabling the differentiation between liquid water and solid ice to some extent and the inversion of the electrical structure of underground media. These conventional techniques provide fundamental support for understanding the hydrothermal evolution of permafrost regions and play a crucial role in the long-term health monitoring of various major infrastructure projects.
[0003] Existing technologies still have limitations in addressing the complex water-salt coupling mechanism during permafrost freezing. Particularly during the advance of the freezing front, the dynamic changes in unfrozen water content lead to a dramatic concentration effect of pore water salts. Current technologies typically use fixed empirical formulas or constant conversion coefficients to estimate salt content, neglecting the dynamic influence of freezing rate and soil structure on salt expulsion efficiency. This results in inaccurate calculations of pore water concentration. Furthermore, sensors buried underground for extended periods are highly susceptible to polarization effects and zero-point drift. The lack of a real-time dynamic calibration mechanism makes it difficult to guarantee measurement stability during long-term freeze-thaw cycles, thus affecting the accurate assessment of water-salt migration patterns in saline soil subgrades. Summary of the Invention
[0004] In view of the aforementioned existing problems, the present invention is proposed.
[0005] Therefore, this invention provides an online monitoring method for water and salt migration in saline-frozen soil subgrades, which solves the technical problems of low accuracy in water and salt state inversion and long-term monitoring data drift caused by the neglect of dynamic changes in salt discharge efficiency during the advance of freezing fronts and the lack of real-time self-calibration mechanism of sensors in existing technologies.
[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution: In a first aspect, the present invention provides an online monitoring method for water and salt migration in saline-frozen soil subgrade, which includes: performing structured data acquisition and preprocessing through a multi-frequency composite probe to generate a structured data frame for the current sampling period; By monitoring the double-ring resistivity response during the crossing of the freezing front, the salt discharge coefficient of each depth layer is dynamically calibrated and corrected in real time, generating an expanded data frame. The thermodynamic consistency between the freezing point of the reference solution in the micro-closed cavity and the actual freezing point of the soil is used to self-calibrate the salinity measurement and generate the final data frame. The hydrothermal-salinous coupled migration model is used to invert the water and salt state variables at each depth and identify the depth of the freezing front, generating a result dataset. Visualized cloud maps and early warning information are generated based on the resulting dataset and then uploaded and pushed out.
[0007] As a preferred embodiment of the online monitoring method for water and salt migration in saline-frozen soil subgrade according to the present invention, the step of generating a structured data frame for the current sampling period by performing structured data acquisition and preprocessing through a multi-frequency composite probe specifically includes: The multi-frequency composite probe is controlled to emit multiple electromagnetic wave signals of different frequencies to the saline-frozen soil subgrade according to a preset sampling period, and the reflected signals corresponding to each frequency are received to extract the original response values of dielectric constant, conductivity and resistivity. The original response values are denoised and smoothed, and the processed data is encapsulated according to depth level and timestamp to generate a structured data frame of the current sampling period of multi-level soil electrical parameters.
[0008] As a preferred embodiment of the online monitoring method for water and salt migration in saline-frozen soil subgrade described in this invention, the method of dynamically calibrating and real-time correcting the salt discharge coefficient of each depth layer by monitoring the double-loop resistivity response during the crossing of the freezing front, and generating extended data frames, specifically includes: Based on the structured data frame, the resistivity abrupt change interface of adjacent electrode pairs on the multi-frequency composite probe in the vertical direction is identified to determine the current freezing front position. The dynamic resistivity change curves fed back by the double-ring electrode structure are monitored as the frozen front traverses layers of various depths. The ratio of unfrozen water content to precipitated salt is calculated based on the dynamic resistivity change curve, and the theoretical salt discharge coefficient is dynamically calibrated and corrected in real time. The corrected salt discharge coefficient is superimposed onto the structured data frame to generate an expanded data frame with dynamically corrected parameters.
[0009] As a preferred embodiment of the online monitoring method for water and salt migration in saline-frozen soil subgrade according to the present invention, the method of self-calibrating salinity measurement by utilizing the thermodynamic consistency between the freezing point of the reference solution in the micro-closed cavity and the actual freezing point of the soil to generate a final data frame specifically includes: Acquire phase transition temperature data of the reference solution in the micro-enclosed cavity buried at the monitoring point, as well as the measured temperature data of the soil at the corresponding depth; The zero-point drift and sensitivity deviation of the salinity sensor are calculated by using the known freezing point curve of the reference solution and the thermodynamic equilibrium relationship between the actual freezing point of the soil. Based on the zero-point drift and sensitivity deviation, the salinity measurement values in the expanded data frame are compensated and corrected to eliminate the interference of ambient temperature fluctuations on salinity measurement and generate the calibrated final data frame.
[0010] As a preferred embodiment of the online monitoring method for water and salt migration in saline-frozen soil subgrade described in this invention, the step of using a hydrothermal-salt coupled migration model to invert the water and salt state variables at each depth and identify the freezing front depth to generate a result dataset specifically includes: The electrical parameters and calibrated salinity values in the final data frame are used as input boundary conditions and imported into a pre-built hydrothermal-salt coupled migration model. The hydrothermal-salt coupled migration model is based on the mass conservation and energy conservation equations. It iteratively solves the coupling state of the water field, temperature field and salinity field at each depth layer, outputs the water content, salinity and unfrozen water content at each depth as water and salt state variables, accurately identifies the current freezing front depth based on temperature gradient and phase change characteristics, and summarizes the results to generate a dataset.
[0011] As a preferred embodiment of the online monitoring method for water and salt migration in saline-frozen soil subgrade described in this invention, the step of generating a visualized cloud map and early warning information based on the result dataset and uploading and pushing it specifically includes: Based on the water and salt state variables and freezing front depth in the result dataset, a two-dimensional visualization cloud map reflecting the water and salt distribution characteristics of the roadbed profile is generated using a spatial interpolation algorithm. The water and salt state variables are compared with preset roadbed stability thresholds. When the water content, salt content, or risk of frost heave deformation exceeds the threshold, early warning information with risk level and treatment suggestions is generated. The visualized cloud map and early warning information are packaged and uploaded to a remote monitoring terminal via a wireless network for push display.
[0012] As a preferred embodiment of the online monitoring method for water and salt migration in saline-frozen soil subgrade described in this invention, the method further includes: establishing a historical monitoring database, storing the result datasets of each sampling period, and predicting the water and salt migration trend and subgrade settlement risk within a future set time period based on time series analysis.
[0013] Secondly, this invention provides an online monitoring system for water and salt migration in saline-frozen soil roadbeds, comprising, The data acquisition module is used to connect to the multi-frequency composite probe, perform structured data acquisition and preprocessing, and generate structured data frames for the current sampling period; The dynamic calibration module is used to monitor the double-loop resistivity response during the crossing of the freezing front, dynamically calibrate and correct the salt discharge coefficient of each depth layer in real time, and generate extended data frames. The self-calibration module is used to self-calibrate the salinity measurement by utilizing the thermodynamic consistency between the freezing point of the reference solution in the micro-closed cavity and the actual freezing point of the soil, and to generate the final data frame. The model inversion module is used to call the preset hydrothermal-salt coupled migration model, invert the water and salt state variables at each depth and identify the depth of the freezing front, and generate the result dataset. The interactive early warning module is used to generate visual cloud maps and early warning information based on the result dataset, and is responsible for uploading and pushing the data.
[0014] Thirdly, the present invention provides a computer device, including a memory and a processor, wherein the memory stores a computer program, wherein when the computer program is executed by the processor, it implements any step of the online monitoring method for water and salt migration in saline frozen soil subgrade as described in the first aspect of the present invention.
[0015] Fourthly, the present invention provides a computer-readable storage medium having a computer program stored thereon, wherein: when the computer program is executed by a processor, it implements any step of the online monitoring method for water and salt migration in saline-frozen soil subgrade as described in the first aspect of the present invention.
[0016] The beneficial effects of this invention are as follows: Structured data frames are generated by collecting and preprocessing the electrical parameters of the roadbed using a multi-frequency composite probe; then, based on the double-loop resistivity response during the crossing of the freezing front, the salt discharge coefficient of each depth layer is dynamically calibrated and corrected in real time using the formula relating the unfrozen water content to the precipitated salt; simultaneously, the zero-point drift and sensitivity deviation are calculated by combining the thermodynamic consistency between the reference solution in the micro-enclosed cavity and the actual freezing point of the soil to complete the self-calibration of salinity measurement; the calibrated data are imported into a hydrothermal-salt coupled migration model to invert the water and salt state variables such as water content and salt content at each depth and accurately identify the depth of the freezing front; based on the inversion results, a two-dimensional visualized cloud map and risk warning information are generated and uploaded, realizing accurate perception, long-term stable monitoring, and intelligent risk warning of the water and salt transport patterns within the saline-frozen soil roadbed. Attached Figure Description
[0017] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0018] Figure 1A flowchart for an online monitoring method for water and salt migration in saline-frozen soil subgrade.
[0019] Figure 2 This is a schematic diagram of an online monitoring system for water and salt migration in saline-frozen soil roadbeds. Detailed Implementation
[0020] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.
[0021] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.
[0022] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.
[0023] Reference Figures 1-2 As one embodiment of the present invention, this embodiment provides an online monitoring method for water and salt migration in saline-frozen soil roadbeds, comprising the following steps: The multi-frequency composite probe is controlled to emit multiple electromagnetic wave signals of different frequencies to the saline-frozen soil subgrade according to a preset sampling period, and the reflected signals corresponding to each frequency are received to extract the original response values of dielectric constant, conductivity and resistivity.
[0024] Furthermore, the signal generator built into the multi-frequency composite probe synchronously excites multiple electromagnetic wave pulses of specific frequencies within a preset sampling period and injects them into the saline-frozen soil subgrade. At the same time, the high-frequency data acquisition module captures the reflected echo signals corresponding to each frequency in real time. After vector calculation, the original response values of dielectric constant, conductivity and resistivity, which characterize the electromagnetic properties of the soil, are separated and extracted.
[0025] The original response values are denoised and smoothed, and the processed data is encapsulated according to depth level and timestamp to generate a structured data frame of the current sampling period of multi-level soil electrical parameters.
[0026] Furthermore, digital signal processing algorithms are used to remove background noise and smooth the original response values to eliminate random interference. Then, the purified multi-frequency electrical parameters are standardized, packaged, and serialized according to the vertical depth distribution of the probe and a unified timestamp sequence, thereby constructing a structured data frame of multi-level soil electrical parameters for the current sampling period containing complete spatiotemporal information.
[0027] Based on the structured data frame, the resistivity abrupt change interface of adjacent electrode pairs on the multi-frequency composite probe in the vertical direction is identified to determine the current freezing front position.
[0028] Furthermore, based on the generated structured data frames, the resistivity gradient change rate between adjacent electrode pairs on the multi-frequency composite probe is calculated by traversing along the vertical depth direction. This accurately captures the characteristic interface where resistivity undergoes a step change due to soil phase transition, thereby determining the specific spatial location of the freezing front inside the saline-frozen soil subgrade at the current moment.
[0029] The dynamic resistivity change curves fed back by the double-ring electrode structure are monitored as the frozen front traverses layers of various depths.
[0030] Furthermore, based on locking the location of the freezing front, the continuous resistivity dynamic change curve, which reflects the pore water freezing and concentration effect, is continuously tracked and recorded by the double-ring electrode structure as the phase change interface traverses each preset depth layer from top to bottom, providing time-series data support for the dynamic calibration of subsequent parameters.
[0031] The ratio of unfrozen water content to precipitated salt is calculated based on the dynamic resistivity change curve, and the theoretical salt discharge coefficient is dynamically calibrated and corrected in real time.
[0032] Furthermore, based on the monitored dynamic resistivity change curve, the real-time pore water conductivity characteristics are inverted. Combined with the phase change law of water during the soil freezing process, the ratio of unfrozen water content to precipitated salt is quantitatively calculated. Then, the theoretical salt discharge coefficient is dynamically calibrated and corrected in real time to eliminate the calculation deviation caused by fixed empirical parameters.
[0033] Specifically, the expression is: ; in, Real-time pore water concentration, The initial pore water concentration, This represents the initial volumetric water content. Real-time unfrozen water content, This is the salt excretion coefficient. The corrected salt discharge coefficient is superimposed onto the structured data frame to generate an expanded data frame with dynamically corrected parameters.
[0034] Furthermore, the salt discharge coefficient, after dynamic calibration and real-time correction, is superimposed on the structured data frame as a key time-varying parameter to form an expanded data frame containing dynamically corrected parameters, providing a reliable data foundation for subsequent high-precision water-salt state inversion.
[0035] The phase transition temperature data of the reference solution in the micro-enclosed cavity buried at the monitoring point, as well as the measured temperature data of the soil at the corresponding depth, are obtained.
[0036] Furthermore, by synchronously collecting real-time phase change temperature data of the reference solution in the miniature closed cavity buried at the monitoring point using a high-precision temperature sensor, as well as measured ambient temperature data of the soil at the corresponding depth layer, a thermodynamic reference system for self-calibration is established.
[0037] By utilizing the known freezing point curve of the reference solution and the thermodynamic equilibrium relationship between the actual freezing point of the soil, the zero-point drift and sensitivity deviation of the salinity sensor are calculated.
[0038] Furthermore, by utilizing the thermodynamic balance and deviation relationship between the known standard freezing point curve of the reference solution and the actual freezing point of the soil, an error analysis model is constructed to accurately calculate the zero-point drift and sensitivity deviation of the salinity sensor during long-term service.
[0039] The expression for zero-point drift is: ; in, This is the zero-point drift amount. The theoretical freezing point of the reference solution. This is the measured freezing point of the sensor under zero-salt conditions; The expression for sensitivity deviation is: ; in, For sensitivity deviation, The theoretical freezing point of the reference solution is nominal. The sensor's measured freezing point - nominal value. The nominal concentration of the reference solution. To reduce the freezing point constant; Based on the zero-point drift and sensitivity deviation, the salinity measurement values in the expanded data frame are compensated and corrected to eliminate the interference of ambient temperature fluctuations on salinity measurement and generate the calibrated final data frame.
[0040] Furthermore, the refined electrical parameters and calibrated high-precision salinity values contained in the final data frame are used as input boundary conditions and imported into a pre-built hydrothermal-salt coupled migration model based on mass and energy conservation to start a multiphysics coupled iterative solution program.
[0041] The electrical parameters and calibrated salinity values in the final data frame are used as input boundary conditions and imported into a pre-built hydrothermal-salt coupled migration model.
[0042] Furthermore, the refined electrical parameters and calibrated high-precision salinity values contained in the final data frame are used as input boundary conditions and imported into a pre-built hydrothermal-salt coupled migration model based on mass and energy conservation to start a multiphysics coupled iterative solution program.
[0043] The hydrothermal-salt coupled migration model is based on the mass conservation and energy conservation equations. It iteratively solves the coupling state of the water field, temperature field and salinity field at each depth layer, outputs the water content, salinity and unfrozen water content at each depth as water and salt state variables, accurately identifies the current freezing front depth based on temperature gradient and phase change characteristics, and summarizes the results to generate a dataset.
[0044] Furthermore, the hydrothermal-salt coupled migration model is driven to perform multi-physics field iterative calculations based on the mass conservation and energy conservation equations, accurately analyze the dynamic coupling state of the water field, temperature field and salinity field at each depth layer, output water and salt state variables including water content, salinity and unfrozen water content, and accurately lock the current freezing front depth based on the temperature gradient abrupt change and phase transition characteristics, and summarize and generate a standardized result dataset.
[0045] Based on the water and salt state variables and freezing front depth in the result dataset, a two-dimensional visualization cloud map reflecting the water and salt distribution characteristics of the roadbed profile is generated using a spatial interpolation algorithm.
[0046] Furthermore, multidimensional water and salt state variables and freezing front depth information are extracted from the result dataset. A continuous spatial distribution matrix is constructed using spatial interpolation algorithms such as Kriging or inverse distance weighting, thereby drawing a two-dimensional visualization cloud map that intuitively reflects the water and salt transport and enrichment characteristics inside the roadbed profile.
[0047] The water and salt state variables are compared with preset roadbed stability thresholds. When the water content, salt content, or risk of frost heave deformation exceeds the threshold, early warning information with risk level and treatment suggestions is generated.
[0048] Furthermore, the real-time inverted water and salt state variables are automatically compared with the pre-set roadbed stability safety threshold. Once the water content or salt content exceeds the standard or the calculated risk of frost heave deformation exceeds the critical value, the alarm mechanism is immediately triggered and an early warning information containing the specific risk level and targeted treatment suggestions is generated.
[0049] The visualized cloud map and early warning information are packaged and uploaded to a remote monitoring terminal via a wireless network for push display.
[0050] Furthermore, the generated two-dimensional visualized cloud map and structured early warning information are encrypted and packaged, and uploaded to the cloud server in real time through the wireless network communication module. Simultaneously, the data is pushed to the human-machine interface of the remote monitoring terminal for visualization, realizing remote and real-time sharing of monitoring data.
[0051] A historical monitoring database is established to store the results datasets from each sampling period. Based on time series analysis, the migration trends of water and salt and the risk of roadbed settlement are predicted for future specified time periods. Furthermore, a long-term historical monitoring database is constructed to persistently store the result datasets of each sampling period, and time series analysis algorithms are used to mine the historical evolution patterns of water and salt migration. Based on this, a forward-looking prediction of water and salt migration trends and potential roadbed settlement risks within a set future time period is made.
[0052] This embodiment also provides an online monitoring system for water and salt migration in saline-frozen soil subgrade, including: a data acquisition module for connecting to a multi-frequency composite probe, performing structured data acquisition and preprocessing, and generating a structured data frame for the current sampling period; The dynamic calibration module is used to monitor the double-loop resistivity response during the crossing of the freezing front, dynamically calibrate and correct the salt discharge coefficient of each depth layer in real time, and generate extended data frames. The self-calibration module is used to self-calibrate the salinity measurement by utilizing the thermodynamic consistency between the freezing point of the reference solution in the micro-closed cavity and the actual freezing point of the soil, and to generate the final data frame. The model inversion module is used to call the preset hydrothermal-salt coupled migration model, invert the water and salt state variables at each depth and identify the depth of the freezing front, and generate the result dataset. The interactive early warning module is used to generate visual cloud maps and early warning information based on the result dataset, and is responsible for uploading and pushing the data.
[0053] This embodiment also provides a computer device applicable to the online monitoring method for water and salt migration in saline-frozen soil subgrade, comprising: a memory and a processor; the memory is used to store computer-executable instructions, and the processor is used to execute the computer-executable instructions to realize the online monitoring method for water and salt migration in saline-frozen soil subgrade as proposed in the above embodiment.
[0054] The computer device can be a terminal, comprising a processor, memory, communication interface, display screen, and input devices connected via a system bus. The processor provides computing and control capabilities. The memory includes non-volatile storage media and internal memory. The non-volatile storage media stores the operating system and computer programs. The internal memory provides an environment for the operation of the operating system and computer programs stored in the non-volatile storage media. The communication interface is used for wired or wireless communication with external terminals; wireless communication can be achieved through Wi-Fi, carrier networks, NFC (Near Field Communication), or other technologies. The display screen can be an LCD screen or an e-ink screen. The input devices can be a touch layer covering the display screen, buttons, a trackball, or a touchpad on the computer device's casing, or an external keyboard, touchpad, or mouse.
[0055] This embodiment also provides a storage medium storing a computer program. When executed by a processor, the program implements the online monitoring method for water and salt migration in saline-frozen soil subgrade as proposed in the above embodiments. The storage medium can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as Static Random Access Memory (SRAM), Electrically Erasable Programmable Read-Only Memory (EEPROM), Erasable Programmable Read Only Memory (EPROM), Programmable Red-Only Memory (PROM), Read-Only Memory (ROM), magnetic storage, flash memory, magnetic disk, or optical disk.
[0056] In summary, this invention uses a multi-frequency composite probe to collect and preprocess roadbed electrical parameters to generate structured data frames. Then, based on the dual-loop resistivity response during the crossing of the freezing front, it dynamically calibrates and corrects the salt discharge coefficient at each depth layer in real time using the formula relating unfrozen water content to precipitated salt. Simultaneously, by combining the thermodynamic consistency between the reference solution in the micro-enclosed cavity and the actual freezing point of the soil, it calculates the zero-point drift and sensitivity deviation to complete the self-calibration of salinity measurement. The calibrated data is imported into a hydrothermal-salt coupled migration model to invert and derive water and salt state variables such as water content and salt content at each depth, accurately identifying the depth of the freezing front. Based on the inversion results, a two-dimensional visualized cloud map and risk warning information are generated and uploaded, achieving accurate perception, long-term stable monitoring, and intelligent risk warning of the water and salt transport patterns within saline-frozen soil roadbeds.
[0057] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.
Claims
1. A method for online monitoring of water and salt migration in saline-frozen soil subgrade, characterized in that: include, Structured data acquisition and preprocessing are performed using a multi-frequency composite probe to generate a structured data frame for the current sampling period; By monitoring the double-ring resistivity response during the crossing of the freezing front, the salt discharge coefficient of each depth layer is dynamically calibrated and corrected in real time, generating an expanded data frame. The thermodynamic consistency between the freezing point of the reference solution in the micro-closed cavity and the actual freezing point of the soil is used to self-calibrate the salinity measurement and generate the final data frame. The hydrothermal-salinous coupled migration model is used to invert the water and salt state variables at each depth and identify the depth of the freezing front, generating a result dataset. Visualized cloud maps and early warning information are generated based on the resulting dataset and then uploaded and pushed out.
2. The online monitoring method for water and salt migration in saline-frozen soil subgrade as described in claim 1, characterized in that: The process of acquiring and preprocessing structured data using a multi-frequency composite probe to generate a structured data frame for the current sampling period specifically includes: The multi-frequency composite probe is controlled to emit multiple electromagnetic wave signals of different frequencies to the saline-frozen soil subgrade according to a preset sampling period, and the reflected signals corresponding to each frequency are received to extract the original response values of dielectric constant, conductivity and resistivity. The original response values are denoised and smoothed, and the processed data is encapsulated according to depth level and timestamp to generate a structured data frame of the current sampling period of multi-level soil electrical parameters.
3. The online monitoring method for water and salt migration in saline-frozen soil subgrade as described in claim 2, characterized in that: The method of dynamically calibrating and real-time correcting the salt expulsion coefficient of each depth layer by monitoring the double-ring resistivity response during the crossing of the freezing front, and generating extended data frames, specifically includes: Based on the structured data frame, the resistivity abrupt change interface of adjacent electrode pairs on the multi-frequency composite probe in the vertical direction is identified to determine the current freezing front position. The dynamic resistivity change curves fed back by the double-ring electrode structure are monitored as the frozen front traverses layers of various depths. The ratio of unfrozen water content to precipitated salt is calculated based on the dynamic resistivity change curve, and the theoretical salt discharge coefficient is dynamically calibrated and corrected in real time. The corrected salt discharge coefficient is superimposed onto the structured data frame to generate an expanded data frame with dynamically corrected parameters.
4. The online monitoring method for water and salt migration in saline-frozen soil subgrade as described in claim 3, characterized in that: The method of self-calibrating salinity measurements by utilizing the thermodynamic consistency between the freezing point of the reference solution in the micro-enclosed cavity and the actual freezing point of the soil to generate a final data frame specifically includes: Acquire phase transition temperature data of the reference solution in the micro-enclosed cavity buried at the monitoring point, as well as the measured temperature data of the soil at the corresponding depth; The zero-point drift and sensitivity deviation of the salinity sensor are calculated by using the known freezing point curve of the reference solution and the thermodynamic equilibrium relationship between the actual freezing point of the soil. Based on the zero-point drift and sensitivity deviation, the salinity measurement values in the expanded data frame are compensated and corrected to eliminate the interference of ambient temperature fluctuations on salinity measurement and generate the calibrated final data frame.
5. The online monitoring method for water and salt migration in saline-frozen soil subgrade as described in claim 4, characterized in that: The process of using a hydrothermal-salinity coupled migration model to invert the water and salt state variables at each depth and identify the depth of the frozen front, generating a result dataset, specifically includes: The electrical parameters and calibrated salinity values in the final data frame are used as input boundary conditions and imported into a pre-built hydrothermal-salt coupled migration model. The hydrothermal-salt coupled migration model is based on the mass conservation and energy conservation equations. It iteratively solves the coupling state of the water field, temperature field and salinity field at each depth layer, outputs the water content, salinity and unfrozen water content at each depth as water and salt state variables, accurately identifies the current freezing front depth based on temperature gradient and phase change characteristics, and summarizes the results to generate a dataset.
6. The online monitoring method for water and salt migration in saline-frozen soil subgrade as described in claim 5, characterized in that: The process of generating visualized cloud maps and early warning information based on the result dataset and uploading and pushing them specifically includes: Based on the water and salt state variables and freezing front depth in the result dataset, a two-dimensional visualization cloud map reflecting the water and salt distribution characteristics of the roadbed profile is generated using a spatial interpolation algorithm. The water and salt state variables are compared with preset roadbed stability thresholds. When the water content, salt content, or risk of frost heave deformation exceeds the threshold, early warning information with risk level and treatment suggestions is generated. The visualized cloud map and early warning information are packaged and uploaded to a remote monitoring terminal via a wireless network for push display.
7. The online monitoring method for water and salt migration in saline-frozen soil subgrade as described in claim 6, characterized in that: It also includes establishing a historical monitoring database, storing the result datasets of each sampling period, and predicting the water and salt migration trend and roadbed settlement risk in the future within a set time period based on time series analysis.
8. An online monitoring system for water and salt migration in saline-frozen soil subgrade, based on the online monitoring method for water and salt migration in saline-frozen soil subgrade according to any one of claims 1 to 7, characterized in that: include, The data acquisition module is used to connect to the multi-frequency composite probe, perform structured data acquisition and preprocessing, and generate structured data frames for the current sampling period; The dynamic calibration module is used to monitor the double-loop resistivity response during the crossing of the freezing front, dynamically calibrate and correct the salt discharge coefficient of each depth layer in real time, and generate extended data frames. The self-calibration module is used to self-calibrate the salinity measurement by utilizing the thermodynamic consistency between the freezing point of the reference solution in the micro-closed cavity and the actual freezing point of the soil, and to generate the final data frame. The model inversion module is used to call the preset hydrothermal-salt coupled migration model, invert the water and salt state variables at each depth and identify the depth of the freezing front, and generate the result dataset. The interactive early warning module is used to generate visual cloud maps and early warning information based on the result dataset, and is responsible for uploading and pushing the data.
9. A computer device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that: When the processor executes the computer program, it implements the steps of the online monitoring method for water and salt migration in saline frozen soil subgrade as described in any one of claims 1 to 7.
10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by the processor, it implements the steps of the online monitoring method for water and salt migration in saline frozen soil subgrade as described in any one of claims 1 to 7.