Testing device and testing method for water vapor migration characteristics of unsaturated soil roadbed

Abstract

The present application discloses a testing device for water vapor migration characteristics of unsaturated soil roadbed and a testing method thereof, and relates to the field of geotechnical engineering technology. The testing device includes a model box, and a moisture regulating component, a first temperature control component, and a second temperature control component arranged in the model box, wherein the first temperature control component is used to be arranged on the top of the sample, the second temperature control component is used to be arranged on the bottom of the sample, and the moisture regulating component is arranged on the second temperature control component; the model box is also provided with a temperature and humidity measuring component, a drainage component, and a displacement sensor, the displacement sensor is used to detect the height change of the sample, the temperature and humidity measuring component is used to measure the temperature and humidity of the sample at different positions, and the first temperature control component includes a water absorption device, and the water absorption device is connected to the drainage component. It can simulate the influence of water vapor migration under different working conditions on the internal performance and humidity change of the roadbed, so that the simulation effect is more in line with the actual engineering.

Description

Technical Field

[0001] The present application relates to the field of geotechnical engineering technology, and in particular to a device and method for testing water vapor migration characteristics of an unsaturated soil roadbed. Background Art

[0002] Moisture is the main factor that causes roadbed diseases and performance degradation. In actual working conditions, the roadbed is affected by climate (rainfall, evaporation), groundwater level and pumping, and its internal moisture migration often occurs simultaneously in liquid and gaseous forms. On the one hand, groundwater migrates upward into the roadbed soil in the form of liquid water under capillary action; on the other hand, gaseous water inside the soil also migrates in the pores of the soil and condenses into water under the action of low temperature on the top surface of the roadbed.

[0003] At present, the research on the change of water content in the roadbed is mainly based on the migration of single-phase liquid water. However, in some arid areas with deep groundwater, the influence of gaseous water migration on the roadbed fill is relatively large and cannot be ignored. At present, domestic research has been carried out on the long-term performance evolution law of the roadbed fill under the action of water vapor migration. Since there are many factors involved in theory, multi-field coupling numerical simulation and theoretical derivation are extremely complex and it is difficult to obtain good calculation results. Therefore, most of the research on the law of water vapor migration in the roadbed is based on indoor experiments.

[0004] Existing test instruments and equipment mainly consider the changing laws of humidity and performance inside the roadbed soil during water vapor migration from two aspects: temperature (temperature difference) and groundwater (fluctuation). They have certain deviations from the actual engineering conditions of the roadbed and cannot accurately simulate the influence of gaseous moisture migration on roadbed humidity and performance under actual conditions. Summary of the invention

[0005] The purpose of this application is to provide a device and method for testing the water vapor migration characteristics of an unsaturated soil roadbed, which can simulate the influence of water vapor migration under different working conditions on the internal performance and humidity changes of the roadbed, so as to make the simulation effect more in line with engineering practice.

[0006] The embodiment of the present application is implemented as follows:

[0007] According to one aspect of an embodiment of the present application, there is provided a device for testing the water vapor migration characteristics of an unsaturated soil roadbed, comprising a model box, and a moisture regulating component, a first temperature control component, and a second temperature control component arranged in the model box, wherein the first temperature control component is used to be arranged on the top of the sample, the second temperature control component is used to be arranged on the bottom of the sample, and the moisture regulating component is arranged on the second temperature control component; a temperature and humidity measuring component, a drainage component, and a displacement sensor are also arranged in the model box, the displacement sensor is used to detect the height change of the sample, the temperature and humidity measuring component is used to measure the temperature and humidity of the sample at different positions, and the first temperature control component includes a water absorption device, and the water absorption device is connected to the drainage component.

[0008] Optionally, the first temperature control component includes a first temperature controller, and a first temperature adjusting plate connected to the first temperature controller, the first temperature adjusting plate is connected to stacked heat transfer baffles, the first temperature adjusting plate is connected to one of the heat transfer baffles through a rotatable adjustable support, the heat transfer baffles are respectively provided with through holes, the two heat transfer baffles rotate with each other to make the through holes open or closed, the first temperature adjusting plate and the rotatable adjustable support form an accommodating cavity, and the water absorption device is located in the accommodating cavity.

[0009] Optionally, the second temperature control component includes a second temperature controller and a second temperature regulating plate connected to the second temperature controller, and a cushion block is provided between the second temperature regulating plate and the bottom wall of the model box.

[0010] Optionally, the moisture regulating component includes a water tank and a control valve connected to the water tank, the control valve is connected to a water outlet pipe, the water outlet pipe is connected to a permeable stone arranged on a second temperature regulating plate, the permeable stone is also connected to a first drain pipe, the first drain pipe is connected to a collecting box, the permeable stone is provided with a baffle, the baffle is used to allow water vapor to pass through and restrict liquid water from passing through, and the baffle is used to place the sample.

[0011] Optionally, the temperature and humidity measurement component includes a data acquisition component and a plurality of probes connected to the data acquisition component, and the plurality of probes are used to be inserted into different positions of the sample in the height direction.

[0012] Optionally, the drainage assembly includes a second drainage pipe connected to the water absorbing device, and a condensate collector connected to the second drainage pipe.

[0013] Optionally, the model box includes a box body and a door body arranged on one side of the box body, the door body is provided with a transparent observation port, the box body is provided with a heat insulation layer and a through hole, the inner circle of the through hole is provided with a sealing ring, and the box body is also provided with a thermometer for observing the temperature inside the box body.

[0014] Another aspect of the embodiment of the present application provides a method for testing water vapor migration characteristics of an unsaturated soil roadbed, using any one of the above-mentioned devices for testing water vapor migration characteristics of an unsaturated soil roadbed to perform testing, the method comprising:

[0015] Prepare a roadbed model sample, and wrap a thermal insulation layer around the outer circle of the sample;

[0016] Inserting a probe of the temperature and humidity test assembly into the sample;

[0017] placing the sample on a moisture conditioning assembly and placing a first temperature control assembly on top of the sample;

[0018] Matching the displacement sensor with the first temperature control component;

[0019] respectively adjusting the first temperature control component, the second temperature control component and the moisture adjustment component;

[0020] Record the data changes of the displacement sensor and the temperature and humidity testing assembly.

[0021] Optionally, the preparing of the roadbed model sample comprises:

[0022] Taking a soil sample to be tested, and conducting an indoor light compaction test to determine the optimum moisture content and maximum dry density of the soil sample;

[0023] The samples are mixed according to the requirements of the compaction degree and moisture content of the roadbed filler in the actual project;

[0024] The soil sample was compacted in two layers, upper and lower.

[0025] Optionally, the separately adjusting the first temperature control component, the second temperature control component and the moisture adjustment component comprises:

[0026] adjusting the temperatures of the first temperature control component and the second temperature control component so that there is a temperature difference between the top and the bottom of the sample;

[0027] Adjust the flow of water in the water conditioning assembly to simulate the height of the groundwater table.

[0028] The beneficial effects of the embodiments of the present application include:

[0029] The unsaturated soil roadbed water vapor migration characteristic test device and its test method provided by the embodiment of the present application are arranged in the model box through the moisture adjustment component, the first temperature control component and the second temperature control component, so as to simulate different working conditions, such as the temperature difference between the surface and the inside of the roadbed, and the groundwater conditions. When collecting data, through the temperature and humidity measurement component and the displacement sensor, while considering the internal humidity and temperature test of the soil body during the water vapor migration process, the soil deformation test analysis is also added, and the evolution law of the unsaturated soil roadbed performance during the water vapor migration process can be obtained at the same time. In addition, by cooperating with the water absorption device and the drainage component, the influence of the droplet back infiltration on the accuracy of the experiment is avoided. By adopting the above form, the evolution law of the roadbed performance under various working conditions can be accurately obtained, and the whole process of the water vapor migration of the roadbed under the influence of various complex environments encountered in the actual project can be simulated, and the evolution law of the physical, mechanical, deformation and other properties of the unsaturated soil roadbed considering the two-way flow of water and gas can be fully grasped, which provides strong theoretical support for the later targeted roadbed treatment and the all-round guarantee project of the roadbed service performance. And when simulating the influence of water vapor migration on the internal performance and humidity changes of the roadbed under different working conditions, the simulation effect is made more in line with engineering reality. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0031] Figure 1 A schematic diagram of the structure of a device for testing water vapor migration characteristics of unsaturated soil roadbed provided in an embodiment of the present application;

[0032] Figure 2 This is a schematic diagram of the structure of the first temperature control component and the drainage component of the embodiment of the present application;

[0033] Figure 3 A schematic diagram of the structure of a first temperature control component provided in an embodiment of the present application;

[0034] Figure 4 A schematic diagram of the structure of the model box provided in the embodiment of the present application;

[0035] Figure 5 Flow chart of a method for testing water vapor migration characteristics of an unsaturated soil roadbed provided in an embodiment of the present application.

[0036] Icons: 100-unsaturated soil roadbed water vapor migration characteristics test device; 110-model box; 112-box; 114-door; 1142-transparent observation port; 116-insulation layer; 118-through hole; 119-sealing ring; 120-water regulation component; 122-water storage tank; 124-control valve; 126-permeable stone; 127-first drainage pipe; 128-collection box; 129-waterproof board; 130-first temperature control component; 132-water absorption device; 134-first Temperature controller; 136-first temperature regulating plate; 137-rotatable adjustable support; 138-heat transfer baffle; 1382-through hole; 140-second temperature control component; 142-second temperature controller; 144-second temperature regulating plate; 150-temperature and humidity measurement component; 152-data acquisition component; 154-probe; 160-drainage component; 162-second drain pipe; 164-condensate collector; 170-displacement sensor; 180-pad; 190-thermometer. DETAILED DESCRIPTION

[0037] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application described and shown in the drawings here can be arranged and designed in various different configurations.

[0038] Therefore, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the present application for which protection is sought, but merely represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application.

[0039] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0040] In the description of this application, it should be noted that the terms "inside", "outside", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the product of the application is usually placed when in use, which is only for the convenience of describing this application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this application. In addition, the terms "first" and "second" are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0041] In the description of this application, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "disposed" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0042] Existing test instruments and equipment mainly consider the change law of humidity and performance inside the roadbed soil during water vapor migration from two aspects: temperature (temperature difference) and groundwater (fluctuation). There is a certain deviation from the actual engineering conditions of the roadbed, and it is impossible to accurately simulate the influence of gaseous water migration on roadbed humidity and performance under actual conditions. In view of the above problems, the embodiments of the present application provide the following technical solutions to overcome the above problems.

[0043] Please refer to Figure 1 The present embodiment provides a device 100 for testing water vapor migration characteristics of an unsaturated soil roadbed, comprising a model box 110, and a moisture regulating component 120, a first temperature control component 130 and a second temperature control component 140 arranged in the model box 110, wherein the first temperature control component 130 is used to be arranged on the top of the sample, the second temperature control component 140 is used to be arranged at the bottom of the sample, and the moisture regulating component 120 is arranged on the second temperature control component 140; a temperature and humidity measuring component 150, a drainage component 160 and a displacement sensor 170 are also arranged in the model box 110, the displacement sensor 170 is used to detect the height change of the sample, the temperature and humidity measuring component 150 is used to measure the temperature and humidity of the sample at different positions, and the first temperature control component 130 includes a water absorbing device 132, and the water absorbing device 132 is connected to the drainage component 160.

[0044] Specifically, the model box 110 is mainly used to ensure the technical performance and operational safety required during the experiment, and to avoid being affected by the external environment during the experiment. A moisture regulating component 120 is set in the model box 110 to simulate groundwater for experiments. The first temperature control component 130 and the second temperature control component 140 are mainly used to simulate the situation where there is a temperature difference in the roadbed under actual working conditions. In addition, the temperature and humidity measurement component 150 set in the model box 110 is mainly used to measure the changes in temperature and humidity in the sample during the experiment. The displacement sensor 170 is used to detect the height change of the sample, so as to know the degree of influence of the temperature change on the contraction or expansion of the sample.

[0045] By connecting the water absorbing device 132 of the first temperature control component 130 with the drainage component 160, when conducting an experiment on the water vapor migration characteristics, it is prevented that the water vapor condenses on the top layer to form droplets and then seeps downward, which is conducive to ensuring the stability during the experiment. At the same time, by connecting the water absorbing device 132 with the drainage component 160, it is prevented that the water in the water absorbing device 132 seeps downward after being saturated. Among them, the water absorbing device 132 can be made of a water absorbing material, and the embodiment of the present application does not make specific restrictions on this.

[0046] It should be noted that the embodiment of the present application does not impose any specific restrictions on the number of groups of samples set in the model box 110. For example, only one group, two groups, or three groups can be set, as long as it can be ensured that each group of samples has a corresponding device to match it. For example, when there are two groups of samples, the required first temperature control component 130 and the second temperature control component 140 also need to be set as two groups.

[0047] The unsaturated soil roadbed water vapor migration characteristic test device 100 provided in the embodiment of the present application is provided with a moisture regulating component 120, a first temperature control component 130 and a second temperature control component 140 in the model box 110, so as to simulate different working conditions, such as the temperature difference between the surface and the interior of the roadbed, and the groundwater conditions. When collecting data, through the temperature and humidity measuring component 150 and the displacement sensor 170, while considering the internal humidity and temperature test of the soil during the water vapor migration process, the soil deformation test analysis is also added, and the evolution law of the unsaturated soil roadbed performance during the water vapor migration process can be obtained at the same time. In addition, the water absorption device 132 and the drainage component 160 are coordinated to avoid the influence of droplet backseepage on the accuracy of the experiment. By adopting the above form, we can accurately obtain the evolution law of roadbed performance under various working conditions, truly simulate the whole process of water vapor migration of roadbed under various complex environments encountered in actual projects, and fully grasp the evolution law of physical, mechanical, deformation and other properties of unsaturated soil roadbed in the process of water and gas bidirectional flow, and provide strong theoretical support for the later targeted roadbed treatment and all-round guarantee of roadbed service performance. And when simulating the influence of water vapor migration on the internal performance and humidity changes of roadbed under different working conditions, the simulation effect is more in line with the actual project.

[0048] like Figure 1 , Figure 2 and Figure 3As shown, the first temperature control component 130 includes a first temperature controller 134, and a first temperature regulating plate 136 connected to the first temperature controller 134, the first temperature regulating plate 136 is connected to stacked heat transfer baffles 138, the first temperature regulating plate 136 is connected to one of the heat transfer baffles 138 through a rotatable adjustable support 137, the heat transfer baffles 138 are respectively provided with through holes 1382, the two heat transfer baffles 138 rotate with each other to make the through holes 1382 conductive or cut off, the first temperature regulating plate 136 and the rotatable adjustable support 137 form an accommodating cavity, and the water absorption device 132 is located in the accommodating cavity.

[0049] Specifically, the first temperature controller 134 is mainly used to control the temperature of the first temperature regulating plate 136 so as to simulate the actual temperature under different working conditions. It can be understood that when the sample is set as two groups, two first temperature regulating plates 136 can be set accordingly, and the same first temperature control component 130 can be used for control. In addition, the drainage component 160 is connected to the water absorption device 132 through the rotatable adjustable support 137, and a switch knob can be set on the rotatable adjustable support 137 to control the conduction between the water absorption device 132 and the drainage component 160.

[0050] By setting a heat transfer baffle 138 on the first temperature regulating plate 136, the heat on the first temperature regulating plate 136 can be evenly transferred to the top of the sample through heat transfer. At the same time, by setting the heat transfer baffle 138 in a stacked and mutually rotatable form, when simulating the actual working environment, by correspondingly connecting the through holes 1382 of the heat transfer baffle 138, the experimental simulation of the change of roadbed performance under the unsealed condition (the roadbed is not closed for drainage or the roadbed is not closed and not drained) can be realized. It can be understood that when the through holes 1382 of the heat transfer baffle 138 are dislocated and cut off, the experimental simulation of the change of roadbed performance under the closed condition (the roadbed is closed and not drained or the roadbed is closed and drained) can be realized. In this way, the performance change law of the internal temperature and humidity of the roadbed fill under different upper road surface base drainage conditions can be considered, so as to more comprehensively realize the simulation of the actual working conditions.

[0051] like Figure 1 As shown, the second temperature control assembly 140 includes a second temperature controller 142 and a second temperature regulating plate 144 connected to the second temperature controller 142 . A cushion block 180 is disposed between the second temperature regulating plate 144 and the bottom wall of the mold box 110 .

[0052] By setting a pad 180 between the second temperature regulating plate 144 and the bottom wall of the model box 110, the second temperature regulating plate 144 can be easily set, and the influence of the model box 110 on the accuracy of the experiment can be avoided. In order to ensure the stability of the first temperature regulating plate 136 and the second temperature regulating plate 144 during use, other areas other than the opposite sides of the two are treated in the form of insulation material and rubber film wrapping to prevent temperature loss, so as to ensure the accuracy of the experiment. In addition, the temperature change range of the first temperature control component 130 and the second temperature control component 140 is -30°C to 60°C (temperature deviation is ±0.01°C, and temperature fluctuation does not exceed ±0.01°C). The target temperature, temperature duration and temperature change mode during the test can be set on the first temperature controller 134 and the second temperature controller 142 connected to the model box 110 to better simulate the changes in the working environment.

[0053] like Figure 1 As shown, the moisture regulating component 120 includes a water storage tank 122, and a control valve 124 connected to the water storage tank 122, the control valve 124 is connected to a water outlet pipe, the water outlet pipe is connected to a permeable stone 126 arranged on the second temperature regulating plate 144, the permeable stone 126 is also connected to a first drain pipe 127, the first drain pipe 127 is connected to a collecting box 128, the permeable stone 126 is provided with a baffle 129, the baffle 129 is used to allow water vapor to pass through and limit the passage of liquid water, and the baffle 129 is used to place samples.

[0054] Specifically, a control valve 124 connected to the water tank 122 is used to control the water replenishment amount, water replenishment speed, water replenishment time and controllable water replenishment interval time, etc. The entire water supply adopts a pressure-free water supply method. When the water in the water tank 122 is insufficient, water can be replenished in the water tank 122. The outlet pipe is connected to the permeable stone 126 to moisten the permeable stone 126 to simulate the groundwater situation. In addition, a water-blocking plate 129 is provided on the permeable stone 126 to allow water vapor to pass through and restrict the passage of liquid water, thereby better simulating the water vapor migration characteristics of an unsaturated soil roadbed. During the experiment, water overflowed from the lower part of the sample, and the drainage was completed through the first drain pipe 127 connected to the permeable stone 126.

[0055] It is understandable that the water-blocking plate 129 may not be provided on the permeable stone 126, so as to realize the separate migration and joint migration of water and gas at the bottom of the sample through different settings. The above-mentioned form provides conditions for simulating the actual situation of the water-gas migration law in arid, rainless and deep groundwater areas, and is convenient for providing basic data support for studying the water-gas migration law.

[0056] like Figure 1As shown, the temperature and humidity measurement component 150 includes a data acquisition component 152 and a plurality of probes 154 connected to the data acquisition component 152. The plurality of probes 154 are used to be inserted into different positions of the sample in the height direction.

[0057] For example, when conducting an experiment, a probe 154 can be set from top to bottom every 5 cm along the height direction of the sample, and the probe 154 can use an anti-corrosion electrode to ensure the reliability of the measurement. In addition, the displacement sensor 170 can also be connected to the data acquisition component 152, so that the real-time monitored temperature, humidity and displacement changes can be collected through the data acquisition component 152, so as to facilitate sorting and analysis.

[0058] like Figure 2 As shown, the drainage assembly 160 includes a second drainage pipe 162 connected to the water absorbing device 132 , and a condensed water collector 164 connected to the second drainage pipe 162 to collect the water absorbed by the water absorbing device 132 .

[0059] like Figure 4 As shown, the model box 110 includes a box body 112 and a door body 114 arranged on one side of the box body 112, a transparent observation port 1142 is arranged on the door body 114, a heat insulation layer 116 and a through hole 118 are arranged on the box body 112, a sealing ring 119 is arranged in the inner circle of the through hole 118, and a thermometer 190 is also arranged in the box body 112 for observing the temperature in the box body 112.

[0060] Specifically, the model box 110 should meet the required technical performance and operational safety protection goals, and realize the functions of heat insulation, heat preservation and moisture retention. For heat insulation and heat preservation, a steel plate can be used to wrap the insulation material (i.e., a heat insulation layer 116 is provided on the box body 112) as a measure to isolate the temperature exchange between the test model box 110 and the outside temperature. In addition, in order to meet the visualization requirements during the experiment, the transparent observation port 1142 can be made of transparent resin, aerogel plate and glass to meet the visualization requirements while ensuring sealing.

[0061] In addition, by setting the door body 114 on one side of the box body 112, it is convenient to open and close the door on the side, which is convenient for taking and placing the sample. By setting the through hole 118 on the box body 112, it is convenient for various data acquisition lines to enter the test box, so as to simulate the working conditions and collect data. The thermometer 190 set in the box body 112 can observe the ambient temperature in the box body 112 to avoid the accuracy of the experimental results being affected by the fluctuation of the ambient temperature in the box body 112. For example, in order to eliminate the influence of temperature on the experimental results, the temperature in the box body 112 can be maintained at 25°C, and the thermometer 190 is used to observe whether the ambient temperature in the box body 112 meets the requirements.

[0062] like Figure 5 As shown, the embodiment of the present application also discloses a method for testing water vapor migration characteristics of an unsaturated soil roadbed, which is tested using the unsaturated soil roadbed water vapor migration characteristics testing device 100 in the above embodiment. The method includes:

[0063] S100. Prepare a roadbed model specimen and wrap a thermal insulation layer around the outer circle of the specimen.

[0064] Specifically, the roadbed model specimen can be prepared into a cylindrical shape. In order to save test time and conduct comparative observation, two groups of parallel tests are carried out respectively. In order to minimize the size effect of the specimen, the size of each group of specimens is set to a cylinder with a diameter of 15 cm and a height of 35 cm. It can also be set to other sizes according to actual needs. The embodiment of the present application does not impose specific restrictions on this. When setting the insulation layer, a layer of rubber film can be first wrapped around the cylindrical specimen, followed by a layer of flexible insulation material, and then a layer of rubber film can be wrapped on the outermost layer. The above method can reduce the influence of the air temperature inside the model box 110 on the temperature of the specimen, and achieve unidirectional temperature control to the greatest extent. At the same time, the double-layer rubber film can effectively ensure the flatness and full contact of the insulation material, soften the compressed insulation material, and achieve a better insulation effect. This three-layer interlayer setting of rubber film, flexible insulation material and rubber film can better achieve insulation and unidirectional temperature control, and has a better experimental effect.

[0065] S200, inserting the probe 154 of the temperature and humidity test assembly into the sample.

[0066] S300 , placing a sample on the moisture adjustment component 120 , and placing the first temperature control component 130 on top of the sample.

[0067] S400 , matching the displacement sensor 170 with the first temperature control component 130 .

[0068] S500, respectively adjusting the first temperature control component 130, the second temperature control component 140 and the moisture adjustment component 120.

[0069] S600, record the data changes of the displacement sensor 170 and the temperature and humidity test assembly.

[0070] The above method can better simulate the internal water vapor migration process of the actual roadbed project, and intuitively obtain the water vapor migration law of the roadbed under different temperature gradients, different groundwater conditions, different unsaturated soil roadbed fillers, and initial filling conditions. Moreover, the test cost is low and the economic benefits are huge. It is conducive to obtaining the distribution of humidity, deformation, and temperature changes of unsaturated soil roadbed under various water vapor migration conditions, which can effectively guide the construction design of roadbed projects and improve project safety.

[0071] In an optional embodiment of the present application, preparing a roadbed model sample includes:

[0072] S110. Take the soil sample to be tested and conduct an indoor light compaction test to determine the optimal moisture content and maximum dry density of the soil sample.

[0073] S120. Mix the samples according to the requirements for compaction degree and moisture content of roadbed fillers in actual projects.

[0074] S130. Compact the soil sample into two layers, upper and lower.

[0075] Specifically, after determining the optimal moisture content and maximum dry density of the soil sample, the sample is made to achieve the best compaction degree to ensure the effect of the experiment. During the compaction process, the soil sample is compacted on both sides to simulate the roadbed and embankment, ensuring that the experimental process matches the actual working conditions.

[0076] In an optional embodiment of the present application, respectively adjusting the first temperature control component 130, the second temperature control component 140 and the moisture adjustment component 120 includes:

[0077] S510, adjusting the temperatures of the first temperature control component 130 and the second temperature control component 140 so that there is a temperature difference between the top and the bottom of the sample;

[0078] S520, adjusting the flow rate of water in the moisture regulating component 120 to simulate the height of the groundwater level.

[0079] Specifically, in actual engineering, a drainage layer is generally set above the top layer of the roadbed below the pavement structure. The existing test instruments do not take into account the changes and differences in soil moisture at the top of the roadbed with and without drainage. In order to make the test closer to the actual project, the present application sets a water-blocking plate 129 to prevent the migration of underground liquid water generated by capillary action, but does not block the migration of gaseous water. The first temperature control component 130 and the second temperature control component 140 are used to separately and effectively obtain the influence of gaseous water migration on the roadbed humidity and performance. In addition, the first temperature control component 130 is combined with the water absorption device 132 through the heat transfer baffle 138, and is connected to the drainage component 160 to monitor the water output. At the same time, by adjusting the flow rate of water in the moisture regulating component 120, it is used to simulate the height of the groundwater level, so as to simulate different working conditions.

[0080] The above description is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A device for testing water vapor migration characteristics of unsaturated soil roadbed, characterized in that: The invention comprises a model box, and a moisture regulating component, a first temperature control component and a second temperature control component arranged in the model box, wherein the first temperature control component is used to be arranged on the top of the sample, the second temperature control component is used to be arranged on the bottom of the sample, and the moisture regulating component is arranged on the second temperature control component; the model box is also provided with a temperature and humidity measuring component, a drainage component and a displacement sensor, the displacement sensor is used to detect the height change of the sample, the temperature and humidity measuring component is used to measure the temperature and humidity of the sample at different positions, the first temperature control component comprises a water absorbing device, and the water absorbing device is connected to the drainage component; the first temperature control component It includes a first temperature controller and a first temperature regulating plate connected to the first temperature controller, the first temperature regulating plate is connected to stacked heat transfer baffles, the first temperature regulating plate is connected to one of the heat transfer baffles through a rotatable adjustable support, the heat transfer baffles are respectively provided with through holes, the two heat transfer baffles rotate with each other to make the through holes connected or blocked, the first temperature regulating plate and the rotatable adjustable support form a accommodating cavity, the water absorbing device is located in the accommodating cavity; the temperature and humidity measurement component includes a data acquisition component, and a plurality of probes connected to the data acquisition component, the plurality of probes are used to be inserted into different positions of the sample in the height direction.

2. The unsaturated soil roadbed water vapor migration characteristics testing device according to claim 1 is characterized in that: The second temperature control component includes a second temperature controller and a second temperature regulating plate connected to the second temperature controller, and a cushion block is arranged between the second temperature regulating plate and the bottom wall of the model box.

3. The unsaturated soil roadbed water vapor migration characteristics testing device according to claim 2 is characterized in that: The moisture regulating component includes a water tank and a control valve connected to the water tank, the control valve is connected to a water outlet pipe, the water outlet pipe is connected to a permeable stone arranged on a second temperature regulating plate, the permeable stone is also connected to a first drain pipe, the first drain pipe is connected to a collecting box, the permeable stone is provided with a baffle, the baffle is used to allow water vapor to pass through and restrict liquid water from passing through, and the baffle is used to place the sample.

4. The unsaturated soil roadbed water vapor migration characteristics testing device according to claim 1, characterized in that: The drainage assembly includes a second drainage pipe connected to the water absorbing device, and a condensed water collector connected to the second drainage pipe.

5. The unsaturated soil roadbed water vapor migration characteristics testing device according to claim 1, characterized in that: The model box includes a box body and a door body arranged on one side of the box body, the door body is provided with a transparent observation port, the box body is provided with a heat insulation layer and a through hole, the inner circle of the through hole is provided with a sealing ring, and the box body is also provided with a thermometer for observing the temperature inside the box body.

6. A method for testing water vapor migration characteristics of unsaturated soil roadbed, characterized in that: The test is performed using the unsaturated soil roadbed water vapor migration characteristic test device according to any one of claims 1 to 5, the method comprising: Preparing a roadbed model sample, and wrapping an insulation layer around the outer circle of the sample; Inserting a probe of the temperature and humidity test assembly into the sample; placing the sample on a moisture conditioning assembly and placing a first temperature control assembly on top of the sample; Matching the displacement sensor with the first temperature control component; respectively adjusting the first temperature control component, the second temperature control component and the moisture adjustment component; Record the data changes of the displacement sensor and the temperature and humidity testing assembly.

7. The method for testing water vapor migration characteristics of unsaturated soil roadbed according to claim 6, characterized in that: The preparation of the roadbed model sample comprises: Taking a soil sample to be tested, and conducting an indoor light compaction test to determine the optimum moisture content and maximum dry density of the soil sample; The samples are mixed according to the requirements of the compaction degree and moisture content of the roadbed filler in the actual project; The soil sample was compacted in two layers, upper and lower.

8. The method for testing water vapor migration characteristics of unsaturated soil roadbed according to claim 6 or 7, characterized in that: The separately regulating the first temperature control component, the second temperature control component and the moisture regulating component comprises: adjusting the temperatures of the first temperature control component and the second temperature control component so that there is a temperature difference between the top and the bottom of the sample; Adjust the flow of water in the water conditioning assembly to simulate the height of the groundwater table.

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