A test system and test method for water vapor migration in soil freeze-thaw process

Abstract

The application provides a test system and a test method for water vapor migration in a soil freezing and thawing process. The system comprises a soil sampling device, a refrigeration system, a water supplementing system, a traffic load simulation system, an air pressure control system and a data analysis system. The system can realize the influence of contact water supplementing, non-contact water supplementing and non-water supplementing on water vapor migration in a one-dimensional freezing and thawing process of soil. The system can study the influence of different temperatures and different freezing times on water vapor migration in the freezing and thawing process of soil by adjusting the temperature and freezing time of the refrigeration device. The system can study the influence of traffic load on water vapor migration in the freezing and thawing process of soil by adjusting the frequency and size of the output load. The system is simple and can realize the research and visual display of the influence of water vapor migration of soil under different water supplementing conditions, freezing and thawing temperatures, freezing and thawing times and traffic load conditions.

Description

Technical Field

[0001] This invention belongs to the technical field of soil freeze-thaw water vapor migration test, and particularly relates to a test system and test method for water vapor migration during soil freeze-thaw process. Background Technology

[0002] The statements in this section are merely background information related to the present invention and do not necessarily constitute prior art.

[0003] Frost heave and thaw settlement in permafrost regions can easily induce pavement cracks and uneven settlement in airports, railways, and highways, posing a serious threat to the long-term service performance of infrastructure in these areas. Researchers have found that water vapor migration during the freezing and thawing process is the main cause of frost heave and thaw settlement. Furthermore, traffic loads significantly influence the temperature and structural characteristics of frozen soil, thereby altering water vapor migration during the freeze-thaw process.

[0004] Patent 202223324553.1 discloses an experimental system for unidirectional freezing and water vapor migration in soil. The device has a complex structure and a complicated process. It does not take into account the influence of traffic load and air pressure environment on soil water vapor migration, and it cannot achieve visualization of the soil freeze-thaw process.

[0005] Therefore, in order to explore the water vapor migration law of soil freeze-thaw process under traffic load and air pressure environment, and to realize data monitoring and visualization of water vapor migration during soil freeze-thaw process under complex environment, it is necessary to design a water vapor migration test device during soil freeze-thaw process, and then reveal the influence of various factors on water vapor migration during soil freeze-thaw process. Summary of the Invention

[0006] To overcome the shortcomings of the prior art, this invention provides a test system and method for measuring water vapor migration during soil freeze-thaw cycles. The device is simple and can realize the study and visualization of the effects of different water replenishment conditions, freeze-thaw temperatures, freeze-thaw times, and traffic loads on soil water vapor migration, thus better serving the research on roadbed engineering defects in frozen soil areas.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] In a first aspect, the present invention provides an experimental system for water vapor migration during soil freeze-thaw processes, comprising: a soil sampling device, a refrigeration system, a water replenishment system, a traffic load simulation system, a pressure control system, and a data analysis system;

[0009] The soil sampling device includes a light-transmitting box, inside which a perforated steel plate is installed, and soil is filled inside the light-transmitting box and above the perforated steel plate.

[0010] The refrigeration system includes a refrigeration device that provides temperature and freezing time adjustable temperature conduction to the soil inside the light-transmitting box in a non-contact manner, thereby simulating the freezing and thawing state of the soil.

[0011] The water replenishment system includes a liquid supply bottle, which supplies liquid to the space enclosed by the light-transmitting box and the porous steel plate. By controlling the height of the liquid supply bottle, the system can switch between different states of soil replenishment, such as contact water replenishment, non-contact water replenishment, and no water replenishment. The liquid in the liquid supply bottle is a fluorescent tracer solution, and the migration of liquid water during the soil freeze-thaw process can be visualized by tracking the fluorescent tracer solution.

[0012] The traffic load simulation system includes a pressure plate and a drive servo motor. The drive servo motor outputs load to the soil through the pressure plate to realize traffic load simulation with adjustable frequency and magnitude.

[0013] The air pressure control system includes a vacuum pump, which is used to change the air pressure environment of the soil.

[0014] The data analysis system is used to analyze dynamic characteristic parameters and visualized images collected during the soil freeze-thaw process to study the water vapor migration patterns during the soil freeze-thaw process under different loads, water replenishment conditions, freezing methods and air pressures.

[0015] Secondly, the present invention provides a test method for water vapor migration during soil freeze-thaw processes, comprising:

[0016] By using a refrigeration system to provide adjustable temperature and freezing time to the soil in the soil sampling device, the freezing and thawing state of the soil can be simulated.

[0017] Liquid is supplied to the space enclosed by the light-transmitting box and the porous steel plate through a water supply system. The height of the liquid supply bottle is controlled to switch between different states of soil water supply, non-contact water supply and no water supply. The liquid in the liquid supply bottle is a fluorescent tracer solution, and the migration of liquid water during the soil freeze-thaw process is visualized by tracking the fluorescent tracer solution.

[0018] The traffic load simulation system provides the soil with an adjustable output load in terms of frequency and magnitude, thereby simulating the traffic load on the soil.

[0019] The air pressure environment of the soil is changed by an air pressure control system;

[0020] By analyzing the dynamic characteristic parameters and visualized images collected during the soil freezing and thawing process using a data analysis system, the study investigates the water vapor migration patterns during the soil freezing and thawing process under different loads, water replenishment conditions, freezing methods, and air pressures.

[0021] The above one or more technical solutions have the following beneficial effects:

[0022] This invention, through the setup of a soil sampling device, a refrigeration system, a water replenishment system, a traffic load simulation system, a pressure control system, and a data analysis system, enables the study of the effects of contact water replenishment, non-contact water replenishment, and no water replenishment on water vapor migration during a one-dimensional freeze-thaw process in soil. By adjusting the temperature and freezing time of the refrigeration device, the influence of different temperatures and freezing times on water vapor migration during the freeze-thaw process can be investigated. Furthermore, by adjusting the frequency and magnitude of the output load, the influence of traffic load on soil water vapor migration during the freeze-thaw process can be studied. This invention features a simple device that enables the study and visualization of the effects of different water replenishment conditions, freeze-thaw temperatures, freeze-thaw times, and traffic loads on soil water vapor migration, better serving the research on roadbed engineering defects in permafrost regions.

[0023] Advantages of additional aspects of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0024] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0025] Figure 1 This is a schematic diagram of the overall structure of an experimental system for water vapor migration during soil freeze-thaw processes, according to Embodiment 1 of the present invention.

[0026] In the diagram, 11. Top cooling unit; 12. Bottom cooling unit; 13. Bottom circulating cold bath plate; 14. Top circulating cold bath plate; 21. Marshall bottle; 22. Water outlet; 23. Perforated steel plate; 31. First thermo-TDR sensor; 32. Second thermo-TDR sensor; 33. Third thermo-TDR sensor; 34. Fourth thermo-TDR sensor; 35. Fifth thermo-TDR sensor; 41. Pressure plate; 42. Screw-driven servo motor; 43. Power supply; 51. Vacuum pump; 61. First ultraviolet lamp; 62. Second ultraviolet lamp; 63. High-speed camera equipment; 7. Acrylic cylinder; 8. Displacement gauge; 91. Data acquisition device; 92. Computer. Detailed Implementation

[0027] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0028] It should be noted that the terminology used herein is for the purpose of describing particular implementations only and is not intended to limit the exemplary implementations of the present invention.

[0029] Where there is no conflict, the embodiments and features in the embodiments of the present invention can be combined with each other.

[0030] Example 1

[0031] This embodiment discloses a test system for water vapor migration during soil freeze-thaw processes, comprising:

[0032] Soil sampling device, refrigeration system, water replenishment system, traffic load simulation system, air pressure control system, and data analysis system;

[0033] The soil sampling device includes a light-transmitting box, inside which a perforated steel plate is installed, and soil is filled inside the light-transmitting box and above the perforated steel plate.

[0034] The refrigeration system includes a refrigeration device that provides temperature and freezing time adjustable temperature conduction to the soil inside the light-transmitting box in a non-contact manner, thereby simulating the freezing and thawing state of the soil.

[0035] The water replenishment system includes a liquid supply bottle, which supplies liquid to the space enclosed by the light-transmitting box and the porous steel plate. By controlling the height of the liquid supply bottle, the system can switch between different states of soil replenishment, such as contact water replenishment, non-contact water replenishment, and no water replenishment. The liquid in the liquid supply bottle is a fluorescent tracer solution, and the migration of liquid water during the soil freeze-thaw process can be visualized by tracking the fluorescent tracer solution.

[0036] The traffic load simulation system includes a pressure plate and a drive servo motor. The drive servo motor outputs load to the soil through the pressure plate to realize traffic load simulation with adjustable frequency and magnitude.

[0037] The air pressure control system includes a vacuum pump, which is used to change the air pressure environment of the soil.

[0038] The data analysis system is used to analyze dynamic characteristic parameters and visualized images collected during the soil freeze-thaw process to study the water vapor migration patterns during the soil freeze-thaw process under different loads, water replenishment conditions, freezing methods and air pressures.

[0039] The following is combined with Figure 1 The experimental system proposed in this embodiment will be described in detail.

[0040] In this embodiment, the cooling system, water supply system, and traffic load simulation system are located at both ends, bottom, and top of the soil sampling device, respectively. The thermo-TDR sensor is located inside the soil sampling device, and the fluorescence tracer technology is located on the right side of the soil sample. The data analysis system is connected to the data acquisition system and the fluorescence tracer system.

[0041] In this embodiment, the soil sampling device includes a light-transmitting box and insulation cotton. The light-transmitting box can be made of acrylic cylinder 7. Side holes are drilled on the same side of the acrylic cylinder 7 to reserve the placement position of the thermo-TDR sensor. A perforated steel plate 23 is installed near the bottom of the acrylic cylinder 7. The space formed by the acrylic cylinder 7 below the perforated steel plate 23 is connected to the water replenishment system, and water is replenished to the space above the perforated steel plate 23.

[0042] The acrylic cylinder 7 provides lateral constraint to the soil, ensuring its shape characteristics, while also allowing the UV light to penetrate the acrylic cylinder 7 to visualize the migration of liquid water in the soil. Insulation cotton is used to fill some of the drilled holes in the acrylic cylinder 7 and to wrap the entire acrylic cylinder 7, reducing heat diffusion from the soil to the outside.

[0043] Optionally, referring to the "Standard for Geotechnical Testing Methods" GB / T 50123-2019, the standard for triaxial test and resonant column test specimens, the soil column height h / diameter D should meet 2.5 to 3.0. The soil sample of this model is 30 cm in diameter and 90 cm in height.

[0044] Optional, the hole spacing of the acrylic cylinder 7 is 15cm.

[0045] Optionally, the acrylic cylinder 7 has a light transmittance of over 95%.

[0046] In this embodiment, the refrigeration system includes a top refrigeration device 11 and a bottom refrigeration device 12. The top refrigeration device 11 is connected to the top circulating cold bath plate 14, and the bottom refrigeration device 12 is connected to the bottom circulating cold bath plate 13. The top circulating cold bath plate 14 and the bottom circulating cold bath plate 13 are not in direct contact with the top and bottom of the soil sample, respectively, and use non-contact heat conduction to circulate low-temperature gas, thereby changing the soil sample temperature. By controlling the input temperature and time of the bottom refrigeration device 12 and the top refrigeration device 11, the freezing and thawing state of the soil sample can be simulated.

[0047] Optionally, the temperature input range of the bottom refrigeration device 12 and the top refrigeration device 11 is -25℃ to 150℃ to meet the freeze-thaw requirements of the soil.

[0048] Optionally, the top circulating cold bath plate 14 and the bottom circulating cold bath plate 13 are made of heat-conducting copper pipes.

[0049] In this embodiment, the water replenishment system includes a Marshall bottle 21, a rubber-plastic hose, a water outlet 22, and a porous steel plate 23. The Marshall bottle 21 is fixed in position by a fixing bracket. The Marshall bottle 21 is connected to the water outlet 22 at the bottom of the acrylic cylinder 7 via the rubber-plastic hose. A porous steel plate 23 is positioned near the bottom of the acrylic cylinder 7, and a soil sample is placed on top of the porous steel plate 23. The porous steel plate 23 guides water to evenly replenish the soil sample while reducing capillary action. A one-way permeable membrane is laid between the porous steel plate 23 and the soil sample to achieve unidirectional water replenishment of the soil sample.

[0050] By adjusting the height of the Marsh bottle 21, the study aims to control whether the water surface inside the acrylic cylinder 7 contacts the porous steel plate 23, thereby studying the effects of soil contact water replenishment, non-contact water replenishment, and no water replenishment on the migration of water vapor inside the soil.

[0051] In this embodiment, the monitoring system includes a thermo-TDR sensor, which is arranged vertically inside the soil sample. The probe of the thermo-TDR sensor is equipped with a thermocouple and a resistance wire. It can accurately measure the soil moisture content, ice content, compaction degree, soil temperature, and freeze-thaw curve by detecting the soil dielectric constant, conductivity, heat capacity parameters, temperature, etc.

[0052] Optionally, the probe of the thermo-TDR sensor is 20cm long and 0.4cm in diameter. The thermo-TDR sensors are spaced 15cm apart.

[0053] Optionally, five holes are provided at equal intervals on the same side of the acrylic cylinder 7 to hold the first thermo-TDR sensor 31, the second thermo-TDR sensor 32, the third thermo-TDR sensor 33, the fourth thermo-TDR sensor 34, and the fifth thermo-TDR sensor 35, respectively.

[0054] In this embodiment, the traffic load simulation system includes a pressure plate 41, a screw-driven servo motor 42, and a power supply 43. The bottom of the pressure plate 41 is in direct contact with the soil sample; the power supply 43 can further control the output load of the screw-driven servo motor 42 by adjusting the input voltage. The pressure plate 41 uniformly transmits stress to the soil sample, eliminating uneven depressions on the soil sample surface caused by stress.

[0055] Optional, the bearing plate 41 is 1cm thick.

[0056] Optionally, the screw-driven servo motor 42 has an inner diameter of 10cm and a maximum output load of 30KN, which meets the requirements of load simulation test.

[0057] Optionally, the input value of the power supply 43 can be programmably controlled, thereby adjusting the output load of the screw-driven servo motor 42 to achieve indoor simulation of sinusoidal traffic load.

[0058] In this embodiment, the air pressure control system includes a vacuum pump 51 and a rubber-plastic hose. One end of the rubber-plastic hose is connected to the top of the soil sample, and the other end is connected to the vacuum pump 51. By controlling the input value of the vacuum pump 51, the air pressure environment of the soil is changed.

[0059] In this embodiment, the fluorescence tracer system includes a fluorescent tracer, a first ultraviolet lamp 61, a second ultraviolet lamp 62, and a high-speed camera 63. The fluorescent tracer is prepared by mixing the fluorescent tracer with distilled water to form a fluorescent tracer solvent, which is pre-injected into the Marvin flask 21, meaning that the fluorescent tracer solution is used in subsequent water replenishment tests. The fluorescent tracer solvent appears bright green under the illumination of the first ultraviolet lamp 61 and the second ultraviolet lamp 62 at a wavelength of 365nm, indicating that the fluorescent tracer solution appears bright green under ultraviolet light when liquid water is present. When the liquid water turns into ice, the bright green color disappears, thus visualizing the migration of liquid water during the freeze-thaw process of the soil. The high-speed camera 63 acquires real-time images of soil fluorescence changes and records the changing trends of fluorescent spots during the freeze-thaw process of the soil.

[0060] In this embodiment, the top of the displacement gauge 8 is constrained by the top circulating cold bath plate 14, and the bottom is in contact with the pressure plate 41. When the soil sample is subjected to the stress of the screw-driven servo motor 42, as well as the freezing and thawing process, the soil sample will undergo a certain deformation. The deformation process of the soil under the coupling effect of multiple physical fields is collected by the displacement gauge 8.

[0061] In this embodiment, the data acquisition and processing system includes a data acquisition unit 91 and a computer 92. The data acquisition unit 91 can acquire data such as temperature, dielectric constant, and conductivity collected by the first thermo-TDR sensor 31, the second thermo-TDR sensor 32, the third thermo-TDR sensor 33, the fourth thermo-TDR sensor 34, and the fifth thermo-TDR sensor 35, as well as images captured by the high-speed camera device 63, in real time, and transmit them to the computer 92. Through thermo-TDR software processing and water vapor migration image processing, the system can accurately detect the moisture content, ice content, compaction degree, temperature, and freeze-thaw curve of the soil under the coupling effect of multiple physical fields, and visualize water vapor migration.

[0062] In terms of soil sample preparation, a multi-layer filling method is adopted according to the pre-established test plan, with each layer being 15cm thick. The sensor layers need to be roughened and the thermo-TDR sensors are laid. After everything is prepared, soil freezing water vapor migration and visualization tests can be carried out under controlled loads (dynamic load, static load, no load), controlled water replenishment (contact water replenishment, non-contact water replenishment, no water replenishment), controlled temperature, controlled one-dimensional freezing mode (unidirectional freezing, bidirectional freezing), and controlled air pressure (positive pressure, negative pressure, normal pressure) according to the test requirements. Data such as water content, ice content, compaction degree, and temperature during the soil freeze-thaw process are obtained, as well as freeze-thaw curves and water content distribution maps.

[0063] A method for conducting water vapor migration tests during soil freeze-thaw cycles using the above-mentioned test system includes the following steps:

[0064] Step 1: After passing the soil sampled on site through a 1mm sieve, dry it and prepare wet soil according to the optimal moisture content.

[0065] Step 2: Close the reserved holes of the soil sampling device, fill the soil with wet soil, fill in layers, each layer is 15cm thick, roughen the layers between the sensor layers, and lay the thermo-TDR sensor to ensure the overall uniformity of the soil sample, and complete the soil sample preparation.

[0066] Step 3: Connect the refrigeration system, adjust the refrigeration temperature according to the test conditions, and turn on the refrigeration device after the test begins.

[0067] Step 4: Pour the fluorescent tracer solution into the Marshall bottle, install the Marshall bottle onto the stand, and ensure that it is connected to the chamber through the rubber hose. By controlling the height of the Marshall bottle, the test conditions can be switched between contact water replenishment, non-contact water replenishment, or no water replenishment.

[0068] Step 5: Adjust the position of the bearing plate to ensure that the bottom of the bearing plate is in complete contact with the soil sample to ensure uniform load transfer. Set the required load size and frequency for the test using computer software to simulate traffic load.

[0069] Step Six: Adjust the air pressure control system to ensure that the vacuum pump is correctly installed and leak-free. Control the air pressure value according to the test requirements and use a barometer to monitor the air pressure changes to ensure that it is within the preset range.

[0070] Step 7: Record the changes in relevant parameters of the soil during the freeze-thaw test using a data analysis system.

[0071] Step 8: After the test, gradually reduce the vacuum pump input intensity to ensure that the air pressure gradually returns to normal pressure and to ensure the safety of the test personnel.

[0072] In this embodiment, by adjusting the vertical height of the Marshall bottle, the effects of contact water replenishment, non-contact water replenishment, and no water replenishment on water vapor migration during the one-dimensional freeze-thaw process of soil can be studied; by controlling the input refrigeration temperature and freezing time of the refrigeration system, the effects of different positive and negative temperatures and the top temperature gradient on water vapor migration during the freeze-thaw process of soil can be studied; by operating the refrigeration system located at the top and shutting off the refrigeration system located at the bottom, the distribution of freezing depth, moisture content, and ice content of different soil types under different freezing conditions can be studied; by adjusting the magnitude and frequency of traffic load, the effect of traffic load on soil water vapor migration during the freeze-thaw process can be studied; by setting the input value of the vacuum pump, the air pressure environment in the soil sample test environment can be controlled; by controlling the cold air input time, the effect of freeze-thaw time on water vapor migration inside the soil can be studied; by changing the soil's own parameters, the effects of soil type, initial moisture content, soil gradation, and other factors on water vapor migration can be studied.

[0073] Example 2

[0074] The purpose of this embodiment is to provide a test method for water vapor migration during soil freeze-thaw processes, including:

[0075] By using a refrigeration system to provide adjustable temperature and freezing time to the soil in the soil sampling device, the freezing and thawing state of the soil can be simulated.

[0076] Liquid is supplied to the space enclosed by the light-transmitting box and the porous steel plate through a water supply system. The height of the liquid supply bottle is controlled to switch between different states of soil water supply, non-contact water supply and no water supply. The liquid in the liquid supply bottle is a fluorescent tracer solution, and the migration of liquid water during the soil freeze-thaw process is visualized by tracking the fluorescent tracer solution.

[0077] The traffic load simulation system provides the soil with an adjustable output load in terms of frequency and magnitude, thereby simulating the traffic load on the soil.

[0078] The air pressure environment of the soil is changed by an air pressure control system;

[0079] By analyzing the dynamic characteristic parameters and visualized images collected during the soil freezing and thawing process using a data analysis system, the study investigates the water vapor migration patterns during the soil freezing and thawing process under different loads, water replenishment conditions, freezing methods, and air pressures.

[0080] In this embodiment, the influence of traffic load on soil water vapor migration during the freeze-thaw process is studied by adjusting the magnitude and frequency of traffic load. The influence on water vapor migration is also studied based on different states of soil during one-dimensional freeze-thaw processes: contact water replenishment, non-contact water replenishment, and no water replenishment. Furthermore, the influence of different positive and negative temperatures and top temperature gradients on water vapor migration during the freeze-thaw process, as well as the influence of different freeze-thaw times on water vapor migration within the soil, is studied by varying the input refrigeration temperature and freezing time of the refrigeration device. By changing the operating mode of the refrigeration device at different locations, the effects of different freezing conditions on the distribution of freezing depth, moisture content, and ice content of different soil types are investigated.

[0081] While the specific embodiments of the present invention have been described above in conjunction with the accompanying drawings, this is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art without creative effort based on the technical solutions of the present invention are still within the scope of protection of the present invention.

Claims

1. A test system for water vapor migration during soil freeze-thaw cycles, characterized in that, include: Soil sampling device, refrigeration system, water replenishment system, traffic load simulation system, air pressure control system, and data analysis system; The soil sampling device includes a light-transmitting box, inside which a porous steel plate is installed, and soil is filled inside the light-transmitting box and above the porous steel plate; a one-way permeable membrane is laid between the porous steel plate and the soil to achieve one-way replenishment of soil moisture. The refrigeration system includes a refrigeration device that provides temperature and freezing time adjustable temperature conduction to the soil inside the light-transmitting box in a non-contact manner to simulate the freezing and thawing state of the soil; the refrigeration system also includes a circulating cold bath plate, which is connected to the refrigeration device and is respectively set at the top and bottom of the soil and is set in a non-contact manner with the soil, thereby changing the soil sample temperature by circulating input and output of low-temperature gas. The water replenishment system includes a liquid supply bottle, which supplies liquid to the space enclosed by the light-transmitting box and the porous steel plate. By controlling the height of the liquid supply bottle, the system can switch between different states of soil replenishment, such as contact water replenishment, non-contact water replenishment, and no water replenishment. The liquid in the liquid supply bottle is a fluorescent tracer solution, and the migration of liquid water during the soil freeze-thaw process can be visualized by tracking the fluorescent tracer solution. The traffic load simulation system includes a pressure plate and a drive servo motor. The drive servo motor outputs load to the soil through the pressure plate to realize traffic load simulation with adjustable frequency and magnitude. The traffic load simulation system includes a pressure plate, a screw-driven servo motor, and a power supply. The bottom of the pressure plate is in direct contact with the soil sample. The power supply can further control the output load of the screw-driven servo motor by adjusting the input voltage. The pressure plate will uniformly transfer stress to the soil sample. The air pressure control system includes a vacuum pump and a rubber-plastic hose. One end of the rubber-plastic hose is connected to the top of the soil sample, and the other end is connected to the vacuum pump. The vacuum pump is used to change the air pressure environment of the soil. The data analysis system is used to analyze dynamic characteristic parameters and visualized images collected during the soil freeze-thaw process to study the water vapor migration patterns during the soil freeze-thaw process under different loads, water replenishment conditions, freezing methods and air pressures.

2. The test system for water vapor migration during soil freeze-thaw processes as described in claim 1, characterized in that, It also includes a data acquisition system, which is communicatively connected to the data analysis system. The data acquisition system includes a thermo-TDR sensor and an image acquisition device. The thermo-TDR sensor is set at different positions inside the light-transmitting box to collect dynamic characteristic parameters of the soil during the freeze-thaw process. The image acquisition device is used to collect visual images of the soil during the freeze-thaw process.

3. The test system for water vapor migration during soil freeze-thaw processes as described in claim 1, characterized in that, It also includes a UV lamp, which is used to irradiate soil containing the fluorescent tracer solvent to visualize the migration of liquid water during the soil freeze-thaw process.

4. The test system for water vapor migration during soil freeze-thaw processes as described in claim 1, characterized in that, It also includes a displacement gauge, one end of which is mounted on the circulating cold bath plate and the other end of which is mounted on the pressure plate. The displacement gauge is used to measure the deformation process of the soil under the coupling effect of multiple physical fields.

5. The test system for water vapor migration during soil freeze-thaw processes as described in claim 2, characterized in that, Multiple side holes are equally spaced on the same side of the light-transmitting box, and the thermo-TDR sensor is installed at the position of each side hole. Insulation cotton is filled between the side hole and the thermo-TDR sensor.

6. A test method for water vapor migration during soil freeze-thaw processes, the method being implemented based on a test apparatus for water vapor migration during soil freeze-thaw processes as described in any one of claims 1-5, characterized in that, include: By using a refrigeration system to provide adjustable temperature and freezing time to the soil in the soil sampling device, the freezing and thawing state of the soil can be simulated. Liquid is supplied to the space enclosed by the light-transmitting box and the porous steel plate through a water supply system. The height of the liquid supply bottle is controlled to switch between different states of soil water supply, non-contact water supply and no water supply. The liquid in the liquid supply bottle is a fluorescent tracer solution, and the migration of liquid water during the soil freeze-thaw process is visualized by tracking the fluorescent tracer solution. The traffic load simulation system provides the soil with an adjustable output load in terms of frequency and magnitude, thereby simulating the traffic load on the soil. The air pressure environment of the soil is changed by an air pressure control system; By analyzing the dynamic characteristic parameters and visualized images collected during the soil freezing and thawing process using a data analysis system, the study investigates the water vapor migration patterns during the soil freezing and thawing process under different loads, water replenishment conditions, freezing methods, and air pressures.

7. The test method for water vapor migration during soil freeze-thaw processes as described in claim 6, characterized in that, Also includes: The influence of traffic load on soil water vapor migration during the freeze-thaw process was studied based on the adjustment of traffic load size and frequency. The study investigated the impact on water vapor migration under different conditions of contact water replenishment, non-contact water replenishment, and no water replenishment during the one-dimensional freeze-thaw process of soil. Based on the different input cooling temperatures and freezing times of the refrigeration device, the effects of different positive temperatures, negative temperatures, and top temperature gradients on water vapor migration during soil freeze-thaw processes, as well as the effects of different freeze-thaw times on water vapor migration within the soil, were studied.

8. The test method for water vapor migration during soil freeze-thaw processes as described in claim 6, characterized in that, By changing the operating mode of the refrigeration device at different locations, the effects of different freezing conditions on the distribution of freezing depth, water content, and ice content of different soil types were studied.

Images