A test device and method for observing vapor water migration

Abstract

The invention discloses a test device and method for observing vapor water migration, comprising a temperature controller, a connecting ring, a host computer and two sample tubes; the two sample tubes are arranged horizontally in a collinear manner, the front ends are arranged with a relative gap, and the two ends of the connecting ring are respectively nested in the front ends of the two sample tubes; the ends of the two sample tubes are respectively detachably provided with a temperature control disk, and the input end of each temperature control disk is connected to an output end of a temperature controller; temperature and humidity sensors are arranged in the two sample tubes and the connecting ring, and the output end of the temperature and humidity sensor is connected to the input end of the host computer. The process of vapor water migration of soil samples can be realized, and the vapor water migration test is realized.

Description

Technical Field

[0001] The invention belongs to the field of soil sample testing and relates to a testing device and method for observing the migration of vapor water. Background Art

[0002] In some arid and semi-arid areas in the northwest, such as Gansu, there is little rainfall, sufficient sunshine, strong evaporation, and the evaporation is much greater than the rainfall. The temperature difference between day and night is large, and the groundwater level is deep. However, the water content at the top of the roadbed has increased in this area. For loess roadbeds, the increase in water content at the top of the roadbed will cause the strength of the roadbed to decrease, the roadbed to shrink, and the formation of a gap between the roadbed and the base. The roadbed is an important supporting structure for the roadbed and pavement structure. The reduction in the strength of the roadbed will inevitably affect the strength and stability of the pavement. Therefore, different degrees of diseases have appeared in this area, such as mesh cracks, longitudinal and transverse cracks, and uneven settlement. Due to geographical and climatic factors, the increase in atmospheric rainfall and groundwater capillary water in the arid and semi-arid areas of the northwest can be ignored. However, the increase in the water content at the top of the roadbed does exist and affects the workability of the pavement.

[0003] At present, semi-rigid base layers are widely used in pavement base layers due to their high stiffness, strong diffusion stress, good water stability and low cost. According to the analysis of many scholars, the soil in the northwest region mainly exists in the form of unsaturated soil. In the three-phase system of unsaturated soil, water molecules, as the most active part, are often affected by the natural environment and are free between the solid phase and the gas phase. When there is a covering layer on the soil base, especially the semi-rigid pavement commonly used in highway engineering, the water vapor in the air-filled zone is blocked during the day and gathers under the covering layer. When the temperature drops at night, the gathered water vapor condenses into liquid water, resulting in an increase in the moisture content under the covering layer, which in turn causes pavement diseases.

[0004] At present, most of the experiments on water vapor migration are studies on liquid water migration. There are few observation devices for studying the migration of vapor water, especially intuitive observation of the migration of vapor water. However, in highway projects in arid and semi-arid areas, the migration of vapor water is the main reason for the increase in moisture content. Therefore, it is very important to design a test device for the migration of vapor water. Summary of the invention

[0005] The purpose of the present invention is to overcome the shortcomings of the above-mentioned prior art and provide a test device and method for observing vapor water migration, which can realize the vapor water migration process of soil samples and realize the vapor water migration test.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] A test device for observing steam water migration, comprising a temperature controller, a connecting ring, a host computer and two sample tubes;

[0008] The two sample tubes are arranged horizontally in a collinear manner, with a relative gap at the front ends, and the two ends of the connecting ring are respectively nested in the front ends of the two sample tubes; a temperature control disk is detachably arranged at the ends of the two sample tubes, and the input end of each temperature control disk is connected to the output end of a temperature controller; temperature and humidity sensors are arranged in the two sample tubes and the connecting ring, and the output end of the temperature and humidity sensor is connected to the input end of the host computer.

[0009] Preferably, each sample tube and the connecting ring is provided with a through hole for the temperature and humidity sensor to pass through.

[0010] Furthermore, each sample tube is provided with three through holes, and the three through holes are respectively located near both ends and in the middle of the sample tube.

[0011] Preferably, a fixing ring is nested on the circumference of the temperature control disk, and the end of the sample tube is nested on the circumference of the fixing ring, and the sample tube is connected to the fixing ring by screws passing through the sample tube.

[0012] Preferably, the front ends of the two sample tubes are provided with gauze.

[0013] Preferably, the two sample tubes are threadedly connected to the connecting ring.

[0014] Preferably, the sample tube is a glass tube.

[0015] An experimental method for observing vapor water migration based on any one of the above-mentioned devices comprises the following steps:

[0016] Step 1: Place two soil samples in two sample tubes respectively, one soil sample is prepared with heavy oxygen water, and the other soil sample is prepared with distilled water; connect the front ends of the two sample tubes through a connecting ring;

[0017] Step 2: Start two temperature controllers to control the temperatures of the two temperature control disks to remain constant, and the temperature difference between the two temperature control disks is 20°C-40°C;

[0018] Step 3: After 7-10 days, turn off the two temperature controllers;

[0019] Step 4, repeating steps 1 to 3, changing the moisture content and ambient temperature of each test soil sample, detecting the content and moisture content of heavy oxygen water in the two soil samples at different moisture contents and ambient temperatures, thereby obtaining vapor water migration data of heavy oxygen water.

[0020] Preferably, the soil samples are filled into the sample tube in layers, with the end of the sample tube being the bottom layer of the soil sample and the front end being the top layer of the soil sample.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] The present invention controls the temperature of the sample tube by a temperature control disk, and can control the temperature of the two sample tubes, so that the vapor water in the soil sample under the temperature difference of the two sample tubes can migrate between the two connected sample tubes, realize the migration process of only the vapor water of the soil sample, and realize the vapor water migration test of the soil sample.

[0023] Furthermore, a gauze is provided at the front end of the two sample tubes to prevent the soil samples in the sample tubes from being disturbed and peeling off, and to avoid interfering with the free flow of vapor water in and out.

[0024] The method of the present invention utilizes the difference between heavy oxygen water and common distilled water, and controls the temperature of two sample tubes through a temperature control plate, so as to intuitively observe the changing law and mechanism of vapor water migration. The present invention is different from other water vapor migration devices in that it studies the migration law of vapor and liquid water, realizes the independent and intuitive observation of vapor water migration, and plays an extremely important role in studying the migration of vapor water. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a structural schematic diagram of the present invention;

[0026] Figure 2 is a cross-sectional view of a sample tube of the present invention;

[0027] Figure 3 For the present invention Figure 2 Enlarged view of point A in the middle.

[0028] Among them: 1-temperature controller; 2-host computer; 3-sample tube; 4-connecting ring; 5-temperature control plate; 6-fixing ring; 7-temperature and humidity sensor; 8-gauze; 9-through hole. DETAILED DESCRIPTION

[0029] The present invention is further described in detail below in conjunction with the accompanying drawings:

[0030] like Figure 1 As shown, the experimental device for observing the migration of vapor water of the present invention comprises a temperature controller 1 , a connecting ring 4 , a host computer 2 and two sample tubes 3 .

[0031] like Figure 2 As shown, two sample tubes 3 are arranged horizontally in a collinear manner with their front ends relatively spaced apart. A gauze mesh 8 is arranged at the front ends of the two sample tubes 3. Both sample tubes 3 are glass tubes with an inner diameter of 60 mm, an outer diameter of 70 mm, a wall thickness of 10 mm and a length of 110 mm.

[0032] The two ends of the connecting ring 4 are respectively nested in the front ends of the two sample tubes 3. The inner diameter of the connecting ring 4 is 70mm, the outer diameter is 80mm, the wall thickness is 10mm, and the length is 40mm. There is a through hole 9 in the middle of the connecting ring 4, which is on the same side as the through hole 9 on the sample tube 3, which is convenient for the installation and removal of the temperature and humidity sensor 7. The connection method between the connecting ring 4 and the two sample tubes 3 is threaded connection. For details, see Figure 3 The front end of the sample tube 3 needs to have a 10 mm thread on its outer surface, and the threads on the front ends of the two sample tubes 3 are opposite.

[0033] The ends of the two sample tubes 3 are detachably provided with a temperature control disk 5, each of which is connected to an output end of a temperature controller 1 at its input end. The temperature control disk 5 has an inner diameter of 50 mm and a thickness of 15 mm. The input end is connected to the output end of the temperature controller 1 through a transmission line. A fixing ring 6 is nested on the circumference of the temperature control disk 5. The fixing ring 6 is a steel ring with an inner diameter of 50 mm, an outer diameter of 60 mm, and a thickness of 10 mm. Threaded holes are opened symmetrically on the upper and lower sides of the middle of the fixing ring 6, with a radius of 2.5 mm and a depth of 5 mm. The ends of the sample tubes 3 are nested on the circumference of the fixing ring 6, and are threadedly connected to the fixing ring 6 by screws passing through the sample tubes 3.

[0034] Each sample tube 3 is provided with three through holes 9 for the temperature and humidity sensor 7 to pass through. The three through holes 9 are respectively located 25 mm, 55 mm and 85 mm away from the front end of the sample tube 3. The two sample tubes 3 and the connecting ring 4 are both provided with temperature and humidity sensors 7. The output end of the temperature and humidity sensor 7 is connected to the input end of the host computer 2 through a sensor line.

[0035] The test process of this device is as follows.

[0036] (1) Prepare the test soil in the test preparation stage. Before preparing the soil sample, the test soil needs to be dried and then prepared. In order to clearly reveal the phenomenon of vapor water migration, one soil sample is prepared with heavy oxygen water and the other soil sample is prepared with distilled water.

[0037] Under the action of temperature difference and water content gradient, the vapor water of the soil sample with high water content in the sample tube 3 with higher temperature will pass through the connecting ring 4 and enter the sample tube 3 of the soil sample with low water content. Since the water used for the soil samples configured in the two sections of the sample tube 3 is different, the heavy oxygen water will penetrate into the sample tube 3 with low water content under the action of the migration of vapor water.

[0038] (2) The amount of test soil for each small section of the sample tube 3 is calculated according to the compaction degree and the volume of the sample tube 3 for the two configured soil samples, and the samples are filled into the sample tube 3 in layers. The filling is carried out in a vertical filling manner, with the end of the sample tube 3 being the bottom layer of the soil sample and the front end being the top layer of the soil sample. Before each layer of filling of the next layer of soil sample, the previous layer of soil needs to be roughened to prevent stratification during filling. During the layered filling process, the temperature and humidity sensors 7 are inserted, each of which passes through the through hole 9 and is placed in the middle of each layer of soil sample.

[0039] (3) After the two organic sample tubes 3 are filled, the front ends of the sample tubes 3 are sealed with gauze.

[0040] (4) Place two sample tubes 3 horizontally in a collinear manner, set a relative gap between the front ends, and connect the two sample tubes 3 using a connecting ring 4. Insert the temperature and humidity sensor 7 into the through hole 9 in the middle of the connecting ring 4. Start the two temperature controllers 1, control the temperature of the temperature control disk 5 to remain constant, and the temperature difference between the two temperature control disks 5 is 20°C-40°C. Observe the changes in the temperature and humidity data. When the temperature and humidity data do not change much, generally after 7-10 days, turn off the two temperature controllers 1.

[0041] (5) After the temperature controller 1 stops, the host computer 2 is used to analyze the temperature and humidity changes of the soil sample.

[0042] (6) The soil samples are taken out of the two sections of the sample tubes 3 in layers, and are contained in multiple sets of aluminum boxes. The content of heavy oxygen water in the soil samples of the two sample tubes 3 is detected by an isotope mass spectrometer. At the same time, the moisture content of the soil samples of the two sample tubes 3 in the aluminum box is measured by a drying method. The moisture content of the soil samples in the aluminum box includes the mass of heavy oxygen water and ordinary distilled water, so the migration change of distilled water in the two sample tubes 3 can also be calculated. In this way, the migration of heavy oxygen water into vapor water under the condition of temperature gradient and moisture content difference can be obtained, and then the change law of vapor water migration of soil samples under different conditions can be obtained.

[0043] The above contents are only for explaining the technical idea of ​​the present invention and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution in accordance with the technical idea proposed by the present invention shall fall within the protection scope of the claims of the present invention.

Claims

1. A test method for observing the migration of vapor water, characterized in that: The test device comprises a temperature controller (1), a connecting ring (4), a host computer (2) and two sample tubes (3); The two sample tubes (3) are arranged horizontally in a collinear manner, with their front ends arranged with a relative gap, and the two ends of the connecting ring (4) are respectively nested in the front ends of the two sample tubes (3); a temperature control disk (5) is detachably arranged at the ends of the two sample tubes (3), and the input end of each temperature control disk (5) is connected to the output end of a temperature controller (1); a temperature and humidity sensor (7) is arranged in the two sample tubes (3) and the connecting ring (4), and the output end of the temperature and humidity sensor (7) is connected to the input end of the host computer (2); Each sample tube (3) and the connecting ring (4) is provided with a through hole (9) for the temperature and humidity sensor (7) to pass through; Each sample tube (3) is provided with three through holes (9), and the three through holes (9) are respectively located near the two ends and the middle of the sample tube (3); A fixing ring (6) is nested on the circumference of the temperature control disk (5), and the end of the sample tube (3) is nested on the circumference of the fixing ring (6) and connected to the fixing ring (6) by screws passing through the sample tube (3); The front ends of the two sample tubes (3) are both provided with gauze (8); The two sample tubes (3) are threadedly connected to the connecting ring (4); The sample tube (3) is a glass tube; The test method includes the following steps: Step 1: Place two soil samples in two sample tubes (3) respectively, one soil sample is prepared with heavy oxygen water, and the other soil sample is prepared with distilled water; connect the front ends of the two sample tubes (3) via a connecting ring (4); Step 2: start the two temperature controllers (1) to control the temperatures of the two temperature control disks (5) to remain constant, and the temperature difference between the two temperature control disks (5) is 20° C.-40° C.; Step 3: After 7-10 days, turn off the two temperature controllers (1); Step 4, repeating steps 1 to 3, changing the moisture content and ambient temperature of each test soil sample, detecting the content and moisture content of heavy oxygen water in the two soil samples at different moisture contents and ambient temperatures, thereby obtaining vapor water migration data of heavy oxygen water.

2. The test method for observing vapor water migration according to claim 1, characterized in that: The soil sample is filled into the sample tube (3) in layers, with the end of the sample tube (3) being the bottom layer of the soil sample and the front end being the top layer of the soil sample.

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