A calculation method for measuring the volumetric deformation of particles

Abstract

The present invention discloses a device and a calculation method for measuring the volume deformation of particles, including a first container. A second container is arranged inside the first container. A precision scale glass tube is provided on the second container. A high-speed camera at the same height as the precision scale glass tube is installed on the inner wall of the first container. An object to be measured is placed inside the second container. A first temperature probe is arranged inside the second container. A cooling sandwich layer is arranged outside the second container. The cooling sandwich layer is connected to a compressor outside the first container through a compressor pipeline. The compressor, the first temperature probe and the high-speed camera are all connected to a data collector through wires. The data collector is communicatively connected to a visual operation terminal. By adopting the device and the calculation method for measuring the volume deformation of particles as described above, the present invention can accurately measure the volume changes of soil particles and ice particles, and is convenient for judging whether the object to be measured is in a "frost heaving" or "frost shrinking" state.

Description

Technical Field

[0001] The present invention relates to the technical field of mechanical engineering, and particularly relates to a device and a calculation method for measuring the volume deformation of particles. Background Art

[0002] In geotechnical tests, the macroscopic changes of the specimen are often closely related to the microscopic changes. The volume change of the soil generally reflects the changes of soil particles or pores in the soil; under certain temperature conditions from positive temperature to negative temperature, the volume change of soil particles follows the law of thermal expansion and contraction. Under negative temperature conditions, during the transition from 0 degree to extremely low temperature, the volume changes of soil particles and the volume of ice in the soil are currently unknown. Therefore, it is necessary to design a device and a method that can explore the volume changes of soil particles and ice in the soil during the transition from 0 degree to extremely low temperature, so as to analyze the law of frost heave change of the soil mass. Summary of the Invention

[0003] The purpose of the present invention is to provide a device and a calculation method for measuring the volume deformation of particles, which can accurately measure the volume changes of soil particles and ice particles, and is convenient for judging whether the object to be measured is in the state of "frost heave" or "frost shrinkage".

[0004] To achieve the above purpose, the present invention provides a device for measuring the volume deformation of particles, including a first container, a first end cover is provided at the top of the first container, a second container is arranged inside the first container, a second end cover is provided at the top of the second container, a precision scale glass tube is provided on the second end cover, and a high-speed camera at the same height as the precision scale glass tube is installed on the inner wall of the first container; the object to be measured is placed inside the second container, and a first temperature probe is arranged inside the second container; a cooling sandwich is arranged outside the second container, and the cooling sandwich is connected to a compressor outside the first container through a compressor pipeline, and the compressor, the first temperature probe and the high-speed camera are all connected to a data collector through wires, and the data collector is communicatively connected to a visualization operation terminal.

[0005] Preferably, sealing rubber rings are provided between the first end cover and the first container and between the second end cover and the second container.

[0006] Preferably, the precision scale glass tube is installed on the second end cover through a sealing plug.

[0007] Preferably, a second temperature probe is arranged inside the object to be measured, and the second temperature probe is connected to the data collector through a wire; the outside of the object to be measured is coated with a plastic film.

[0008] A calculation method for measuring the volume deformation of particles includes the following steps:

[0009] S1. Obtain the object to be measured;

[0010] S2. Place the second temperature probe inside the object to be measured, evacuate the air and seal the object to be measured with a plastic film.

[0011] S3. Place the object to be measured into the second container, cover the second end cap and inject kerosene into the second container through a precision graduated glass tube so that the liquid level of the kerosene is inside the precision graduated glass tube.

[0012] S4. After standing still, start the high-speed camera to read the liquid level of the kerosene in the precision graduated glass tube, start the data collector, visualization operation terminal, compressor, first temperature probe and second temperature probe. After setting the measurement temperature, stand still again so that the temperatures of the kerosene and the object to be measured both stably reach the set temperature, and then calculate the change in the reading in the precision graduated glass tube.

[0013] S5. Turn off each instrument, take out the object to be measured, remove the gas and measure the change in volume of the object to be measured to obtain the volume of the gas discharged from the object to be measured.

[0014] S6. Calculate the kerosene evaporation amount using the formula as follows:

[0015] G coil =M×(0.000352 + 0.000786V)P×F×B

[0016] where G coil is the kerosene evaporation amount, M is the molecular weight of kerosene, V is the air flow velocity on the surface of kerosene, P is the vapor partial pressure in the air at the liquid temperature, F is the bottom area of the precision graduated glass tube, and B is the correction coefficient for kerosene evaporation.

[0017] S7. Calculate the total volume change of the object to be measured using the formula as follows:

[0018]

[0019] where △V 1 is the total volume change of the object to be measured, △V c is the change in the reading in the precision graduated glass tube, t is the freezing time, is the kerosene volume correction coefficient, n is the porosity of the object to be measured, △V gas is the influence on the volume of the soil body after part of the gas is discharged; △V p is the volume change of the air inside the plastic film; V soil is the volume of the object to be measured, S r is the soil saturation degree, S c is the soil salt content, C s is the salt crystal volume correction coefficient;

[0020] S8. Use a nuclear magnetic resonance instrument to detect the object to be measured and measure the content V of its unfrozen water liquid , and then use the resistance method to measure the true volume V of ice in the object to be measured il . Calculate the change volume △V of ice using the ice volume change formula i . The calculation formula is as follows

[0021]

[0022] Among them, m soil is the mass of the object to be measured is the moisture content of the object to be measured is the density of water is the density of ice

[0023] S9. Calculate the ice particle volume change rate k using the formula 1 . The formula is as follows

[0024]

[0025] S10. Obtain the volume change △V of the object to be measured by subtracting the change volume △V of ice from the total volume change amount △V of the object to be measured 1 . The formula is as follows i . Then, calculate the soil particle volume change rate k using the formula soil . The formula is as follows

[0026]

[0027] . Then, calculate the soil particle volume change rate k using the formula 2 . The formula is as follows

[0028] .

[0029] Therefore, the present invention adopts the above-mentioned device and calculation method for measuring the volume deformation of particles, which can accurately measure the volume changes of soil particles and ice particles, and is convenient for judging whether the object to be measured is in the "frost heaving" or "frost shrinkage" state

[0030] Next, through the drawings and embodiments, the technical solution of the present invention will be further described in detail Brief Description of the Drawings

[0031] Figure 1 is a schematic structural diagram of an embodiment of a device for measuring the volume deformation of particles according to the present invention

[0032] Reference Signs

[0033] 1. Data collector; 2. Compressor; 3. Compressor pipeline; 4. First container; 5. First end cover; 6. Second container; 7. Second end cover; 8. Object to be measured; 9. Precision scale glass tube; 10. Sealing plug; 11. High-speed camera; 12. Cooling sandwich; 13. First temperature probe; 14. Second temperature probe; 15. Visual operation terminal. Detailed implementation mode

[0034] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0035] Unless otherwise defined, the technical terms or scientific terms used in the present invention shall have the ordinary meanings understood by those with ordinary skills in the field to which the present invention belongs. The "first", "second" and similar words used in the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. Words such as "including" or "comprising" mean that the elements or objects appearing before this word cover the elements or objects listed after this word and their equivalents, without excluding other elements or objects. Words such as "connected" or "linked" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right", etc. are only used to represent relative position relationships. When the absolute position of the object being described changes, the relative position relationship may also change accordingly.

[0036] Embodiment 1

[0037] As Figure 1 shown, the present invention provides a device for measuring the volume deformation of particles, including a first container 4. A first end cover 5 is provided at the top of the first container 4 for sealing the first container 4. A second container 6 is provided inside the first container 4. A second end cover 7 is provided at the top of the second container 6 for sealing the second container 6. Sealing rubber rings are provided between the first end cover 5 and the first container 4 and between the second end cover 7 and the second container 6, which can further ensure the sealing effect of the first container 4 and the second container 6.

[0038] A precision scale glass tube 9 is provided on the second end cover 7, which can facilitate observing the height change of the kerosene liquid level inside the second container 6. The precision scale glass tube 9 is installed on the second end cover 7 through a sealing plug 10, which can effectively prevent kerosene from leaking from the connection between the precision scale glass tube 9 and the second end cover 7. A high-speed camera 11 with the same height as the precision scale glass tube 9 is installed on the inner wall of the first container 4, which is convenient for continuously photographing the liquid level height in the precision scale glass tube 9 and is easy to read the value.

[0039] A first temperature probe 13 is provided inside the second container 6 for measuring the temperature of the kerosene injected into the second container 6 at a later stage. An object 8 to be measured is placed inside the second container 6, and a second temperature probe 14 is provided inside the object 8 to be measured for measuring the temperature inside the object 8 to be measured. The outside of the object 8 to be measured is coated with a plastic film to prevent errors caused by the contact between the object 8 to be measured and the kerosene.

[0040] A cooling sandwich layer 12 is provided outside the second container 6, and the cooling sandwich layer 12 is filled with a refrigerant. The cooling sandwich layer 12 is connected to a compressor 2 outside the first container 4 through a compressor pipeline 3. By operating the compressor 3, the refrigerant in the cooling sandwich layer 12 is cooled, and the kerosene is indirectly cooled.

[0041] The compressor 2, the first temperature probe 13, the second temperature probe 14, and the high-speed camera 11 are all connected to a data collector 1 through wires. Through the data collector 1, the temperature change of the kerosene can be controlled and displayed, the temperatures of each temperature probe can be displayed, the start of the compressor 2 can be controlled, the time interval for the high-speed camera 11 to take pictures can be controlled, and data can be uploaded and downloaded. The data collector 1 is communicatively connected to a visual operation terminal 15. The visual operation terminal 15 can also display and control the photos taken by the high-speed camera 11 and display and control the temperature.

[0042] The present invention also provides a calculation method for determining the volume deformation of particles, including the following steps:

[0043] S1. Obtain the object to be measured;

[0044] S2. Place the second temperature probe 14 inside the object 8 to be measured, evacuate the air, and seal the object 8 to be measured with a plastic film;

[0045] S3. Place the object 8 to be measured into the second container 6, cover the second end cap 7, and inject kerosene into the second container 6 through a precision scale glass tube 9 so that the liquid level of the kerosene is inside the precision scale glass tube 9;

[0046] S4. After standing, start the high-speed camera 11 to read the liquid level of the kerosene in the precision scale glass tube 9, start the data collector 1, the visual operation terminal 15, the compressor 2, the first temperature probe 13, and the second temperature probe 14. After setting the measurement temperature, stand again so that the temperatures of the kerosene and the object 8 to be measured both stably reach the set temperature, and then calculate the change amount of the reading in the precision scale glass tube 9;

[0047] S5. Turn off each instrument, take out the object 8 to be measured, remove the gas, and measure the volume change amount of the object 8 to be measured to obtain the volume of the gas discharged by the object 8 to be measured;

[0048] S6. Calculate the kerosene volatilization amount using the formula. The formula is as follows:

[0049] G coil = M × (0.000352 + 0.000786V)P × F × B

[0050] Among them, G coil is the kerosene evaporation amount, M is the molecular weight of kerosene, V is the air flow velocity on the kerosene surface, P is the vapor partial pressure in the air at the liquid temperature, F is the bottom area of the precision scale glass tube, and B is the correction coefficient for kerosene evaporation;

[0051] S7. Calculate the total volume change amount of the object to be measured 8 using the formula as follows:

[0052]

[0053] Among them, △V 1 is the total volume change amount of the object to be measured, △V c is the reading change amount in the precision scale glass tube, t is the freezing time, is the kerosene volume correction coefficient, n is the porosity of the object to be measured, △V gas is the influence on the volume of the soil itself after part of the gas is discharged; △V p is the volume change amount of the air in the plastic film; V soil is the volume of the object to be measured, S r is the soil saturation degree, S c is the soil salt content, C s is the salt crystal volume correction coefficient;

[0054] S8. Detect the object to be measured using a nuclear magnetic resonance instrument to measure the content of unfrozen water V liquid , and then measure the true volume V of ice in the object to be measured using the resistance method il , and calculate the volume change amount △V of ice using the ice volume change formula i , and the calculation formula is as follows:

[0055]

[0056] Among them, m soil is the mass of the object to be measured, is the water content rate of the object to be measured, is the density of water, is the density of ice;

[0057] S9. Calculate the ice particle volume change rate k 1 using the formula as follows:

[0058]

[0059] S10. Subtract the volume change amount △V of ice 1 from the total volume change amount △V of the object to be measured iObtain the volume change △V of the object to be measured soil , and the formula is as follows:

[0060]

[0061] Then, use the formula to calculate the volume change rate k of the soil particles 2 , and the formula is as follows:

[0062]

[0063] In this embodiment, the specific operation is as follows:

[0064] Obtain a type of soil, that is, the object to be measured 8. Use the cutting ring method to measure the porosity of the soil as n = 35%, and it can be obtained that n s = 65% (n s is the volume fraction of the solid phase skeleton of the soil mass). Measure the soil saturation S r = 50% by the capillary method, and measure the soil salt content S c = 0.4% by the conductivity method. Dry part of the soil to obtain its water content = 9%.

[0065] Take a soil sample with a volume V soil = 119 cm 3 , and a mass m soil = 255.51 g, then the object to be measured 8 is obtained.

[0066] Turn off all the instruments in this device. Then open the first end cover 5 and the second end cover 7. Wrap the obtained soil sample and the second temperature probe 14 with plastic film, discharge all the air, tie a rubber band to make it airtight, and then place it in the second container 6. Put a sealing rubber ring around the second end cover 7 and cover the second end cover 7 with the precision scale glass tube 9. Slowly pour kerosene from the mouth of the precision scale glass tube 9 until the liquid level of the kerosene is about 15 ml in the precision scale glass tube 9 and stop. Put a sealing rubber ring around the first end cover 5 and cover the first end cover 5 on the first container 4. After ensuring airtightness, start all the instruments, turn on the high-speed camera 11, and let it stand for three hours. Wait for the liquid level in the precision scale glass tube 9 to stabilize and then take a reading.

[0067] After the liquid level stabilizes, the reading is 12.77 ml. Open the visualization operation terminal 15, set the temperature to -6 °C. After both the first temperature probe 13 and the second temperature probe 14 reach -6 °C, maintain for six hours and then take a reading to ensure that the state of the soil mass and the liquid level are both stable.

[0068] The reading of the precision scale glass tube 9 obtained by the high-speed camera 11 is 8.85 ml, that is, the change amount △V c=-3.92 ml. Turn off the instrument, take out the soil sample, remove the gas, and it is found that the volume of the soil mass has changed by 1 cm 3 , that is, the gas discharged by the soil mass = 1 cm 3 .

[0069] Due to its own physical properties and the influence of the external environment, there is a certain amount of evaporation of kerosene. Use the formula: G coil =M×(0.000352 + 0.000786V)P×F×B to calculate it. Among them, the bottom area F of the precision graduated glass tube 9 = 6.25π×10-4 m 2 , the air flow velocity on the surface of the kerosene is taken as V = 0.35 m / s. The molecular weight M of the kerosene used is approximately 135.989, the correction coefficient B for kerosene evaporation = 0.15, the vapor partial pressure (mmHg) in the air at the liquid temperature P = 23.756, and the density of the kerosene used is approximately 1.1132 kg / L, and G coil = 0.00059667 L.

[0070] Use the formula: (When S r is 1, it does not exist)

[0071] Take the volume correction coefficient of kerosene = 1.5%, and the volume correction coefficient C for salt crystallization s = 10%. Substitute into the formula to get △V 1 =-2.268775369 cm 3 .

[0072] Use a nuclear magnetic resonance instrument to detect the soil sample, and measure the content V of unfrozen water liquid = 0.9 cm 3 , and use the resistance method to measure the true volume V of ice in the soil sample il = 24.2329 cm 3 , use the ice volume change formula:

[0073]

[0074] Among them, △V i is the true volume of ice in the soil sample minus the theoretical volume of ice in the soil sample (the mass of water minus the mass of unfrozen water divided by the density of ice), which is the change volume of ice. The density of water = 1 g / cm 3 , and the density of ice = 0.9 g / cm 3 , and △V i =-0.3181 cm 3 .

[0075] Through the formula for the volume change rate of ice particles:

[0076]

[0077] k can be obtained 1 = -1.3126782%, representing a 1.3126782% reduction in the volume of ice particles.

[0078] The change in the total volume of the soil sample minus the change in the volume of ice gives the change in the volume of the soil, , that is, △V soil = -1.950675369 cm 3 .

[0079] The volume change rate of the soil is equal to the change in the volume of the soil divided by the total volume of the soil minus the volume of air, ice, and water in the soil

[0080] Through the formula for the volume change rate of soil particles, it can be obtained that:

[0081]

[0082] The volume change rate k of soil particles 2 = -2.1000502%, representing a 2.1000502% reduction in the volume of soil particles.

[0083] Therefore, by using the above device and calculation method for measuring the volume deformation of particles, the volume changes of soil particles and ice particles can be accurately measured, which is convenient for judging whether the object to be measured is in a "frost heaving" or "frost shrinking" state.

[0084] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that: they can still modify or equivalently replace the technical solutions of the present invention, and these modifications or equivalent replacements cannot make the modified technical solutions deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A calculation method for measuring particle volume deformation, characterized in that: The following steps are involved: S1. Obtain the object to be tested; S2. Place the second temperature probe inside the object to be measured, exhaust the air and use a plastic film to seal the object to be measured; S3, placing the object to be measured into the second container, covering it with the second end cap, and injecting kerosene into the second container through the precision-calibrated glass tube, so that the liquid level of the kerosene is located in the precision-calibrated glass tube; S4. After standing still, start the high-speed camera to read the liquid level of kerosene in the precision scale glass tube, start the data acquisition device, the visual operation terminal, the compressor, the first temperature probe and the second temperature probe, set the measurement temperature and then stand still again to make the temperature of the kerosene and the object to be measured reach the set temperature stably, and then calculate the change in the reading in the precision scale glass tube ; S5. Turn off all instruments, take out the object to be tested, exhaust the gas and measure the volume change of the object to be tested to obtain the volume of gas exhausted by the object to be tested. ; S6. Calculate the volatile amount of kerosene using the formula, the formula is as follows: G coil =M×(0.000352+0.000786V)P×F×B Among them, G coil is the volatile amount of kerosene, M is the molecular weight of kerosene, V is the air velocity on the surface of kerosene, P is the vapor partial pressure in the air at liquid temperature, F is the bottom area of ​​the precision-calibrated glass tube, and B is the correction factor for kerosene evaporation; S7. Calculate the total volume change of the object to be measured using the formula, which is as follows: Among them, △V1 is the total volume change of the object to be measured, △V c is the change in reading in the precision scale glass tube, t is the freezing time, is the kerosene volume correction coefficient, n is the porosity of the object to be measured, △V gas is the effect of part of the gas being discharged on the volume of the soil itself; △V p V is the volume change of the air in the plastic film; soil is the volume of the object to be measured, S r is the soil saturation, S c is the soil salt content, C s is the salt crystal volume correction factor; S8. Use a nuclear magnetic resonance instrument to test the object to be tested and measure the content of unfrozen water V liquid , and then use the resistance method to measure the actual volume V of the ice in the object to be measured il , use the ice volume change formula to calculate the change in ice volume △V i , the calculation formula is as follows: Among them, m soil is the mass of the object to be measured, is the moisture content of the object to be tested, is the density of water, is the density of ice; S9. Calculate the ice particle volume change rate k1 using the formula, which is as follows: S10, subtract the change in volume of ice △V from the total volume change △V1 of the object to be measured i Get the volume change △V of the object to be measured soil , the formula is as follows: Then, the soil particle volume change rate k2 is calculated using the formula as follows: 。

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