Porosity measuring device and porosity measuring method

Abstract

The embodiments of the present invention provide a porosity measuring device and a porosity measuring method, which relate to the technical field of porosity measurement. The porosity measuring device includes a first container, a connecting pipe, a second container and a vacuum pump; the first container is filled with liquid, the first container is connected to one end of the connecting pipe, the other end of the connecting pipe is connected to the second container, the second container is used to place the sample to be tested, and the vacuum pump is connected to the second container. A first valve is provided between the vacuum pump and the second container, and a second valve is provided between the second container and the connecting pipe; the vacuum pump is used to control the pressure of the second container when the first valve is open and the second valve is closed. By observing the change in the liquid level in the first container, the porosity of the sample to be tested can be calculated. The structure is simple, the operation is convenient, the detection speed is fast, and the porosity measuring device is easy to carry and suitable for field measurement.

Description

Technical Field

[0001] The present invention relates to the technical field of porosity measurement, and in particular to a porosity measurement device and a porosity measurement method. Background Art

[0002] At present, the mainstream methods for measuring soil porosity mainly include water absorption method and gas expansion replacement method. Among them, the water absorption method refers to first taking a sample of soil with a ring knife and placing it together with the ring knife in a container containing water. The water level is not higher than the height of the ring knife. After immersion for 24 hours, it is weighed, and then placed in a 105°C oven for 24 hours. The soil sample is dried and weighed again to obtain the volume saturated moisture content. Because the specific gravity of water is 1, the volume saturated moisture content is theoretically directly equal to the porosity. This method has a long measurement cycle, and muddy water after immersion is easy to contaminate the measuring device, and it cannot be reused in a short time.

[0003] The gas expansion displacement method first records the diameter and length of the steel disc and the rock sample, then adjusts the atmospheric pressure of the core chamber, puts in the sample, rotates the T-shaped handle, adjusts the pressure to 560kPa, records the standard chamber pressure P1, then allows the gas to expand into the core chamber, records the equilibrium pressure P2, and finally calculates the volume of each steel disc and the surface volume of the rock mass according to the formula. This measurement method has low accuracy and requires pressurization, has high safety requirements during operation, and is limited in use and inconvenient to carry. Summary of the invention

[0004] The objects of the present invention include, for example, providing a porosity measuring device and a porosity measuring method, which can shorten the measurement cycle and improve the measurement efficiency; have high accuracy, are easy and safe to operate, are easy to carry, and are suitable for field measurement work without the need to bring samples back to the laboratory for measurement.

[0005] The embodiments of the present invention can be implemented as follows:

[0006] In a first aspect, an embodiment of the present invention provides a porosity measurement device, comprising a first container, a connecting pipe, a second container and a vacuum pump; the first container contains a liquid, the first container is connected to one end of the connecting pipe, the other end of the connecting pipe is connected to the second container, the second container is used to place a sample to be measured, and the vacuum pump is connected to the second container;

[0007] A first valve is provided between the vacuum pump and the second container, and a second valve is provided between the second container and the connecting pipe; the vacuum pump is used to control the pressure of the second container when the first valve is open and the second valve is closed.

[0008] In an optional embodiment, the connecting tube includes a first connecting tube and a second connecting tube, one end of the first connecting tube is connected to the first container, the other end of the first connecting tube is connected to one end of the second connecting tube, and the other end of the second connecting tube is connected to the second container.

[0009] In an optional embodiment, a diameter of the first connecting tube is greater than a diameter of the second connecting tube.

[0010] In an optional embodiment, the diameter of the first connecting tube is 2 cm to 4 cm, and the diameter of the second connecting tube is 0.5 cm to 1 cm.

[0011] In an optional embodiment, the volume of the first connecting tube is 30 ml to 50 ml.

[0012] In an optional embodiment, the second connecting pipe includes a first vertical section, a horizontal section, and a second vertical section, one end of the first vertical section is connected to the first connecting pipe, the other end of the first vertical section is connected to one end of the horizontal section, the other end of the horizontal section is connected to one end of the second vertical section, and the other end of the second vertical section is connected to the second container.

[0013] In an optional embodiment, the volume of the first vertical section is 10 ml to 20 ml.

[0014] In an optional embodiment, the volume of the first container is equal to the volume of the second container.

[0015] In an optional embodiment, the second container is provided with a degassing valve.

[0016] In a second aspect, an embodiment of the present invention provides a porosity measurement method, which is applied to a porosity measurement device as described in any one of the aforementioned embodiments, comprising:

[0017] Before placing the sample to be tested, the first valve is opened, the second valve is closed, and the vacuum pump controls the pressure in the second container to be a preset pressure;

[0018] closing the first valve, opening the second valve, and recording a first liquid level height of the liquid;

[0019] placing a sample to be tested in the second container;

[0020] Open the first valve, close the second valve, start the vacuum pump to control the pressure in the second container to the preset pressure, close the first valve; open the second valve, and record the second liquid level height of the liquid;

[0021] The porosity of the sample to be tested is calculated according to the first liquid level height and the second liquid level height.

[0022] The beneficial effects of the embodiments of the present invention include, for example:

[0023] The porosity measuring device provided by the embodiment of the present invention connects the first container and the second container through a connecting pipe, the first container is provided with liquid, the sample to be tested is placed in the second container, the pressure in the second container is controlled to a preset pressure by a vacuum pump, and then the first container and the second container are connected through a second valve, and the pressure difference between the first container and the second container is used to change the height of the liquid level in the first container, and the height difference of the liquid level in the first container is converted into the porosity of the sample to be tested. The porosity measuring device has a simple structure, a small size, is easy to carry, and is flexible and convenient to use. It can be used for field measurement work without taking the sample to be tested back to the laboratory for measurement; and has high measurement efficiency and accurate and reliable results.

[0024] The porosity measurement method provided by the embodiment of the present invention controls the air pressure of the second container by a vacuum pump, and utilizes the air pressure difference between the first container and the second container, so that after the first container and the second container are connected, the air pressure difference drives the liquid level in the first container to change, thereby calculating the porosity of the sample to be measured according to the moving height of the liquid level. The porosity measurement method is simple to operate, highly safe, has a short measurement cycle, high efficiency, and accurate and reliable results. It can be used not only for laboratory measurements, but also for field measurement work, is flexible to use, and has great promotion and application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention 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 creative work.

[0026] Figure 1 A schematic diagram of a first structure of a porosity measurement device provided in a specific embodiment of the present invention;

[0027] Figure 2 A second structural schematic diagram of a porosity measurement device provided in a specific embodiment of the present invention;

[0028] Figure 3 A third structural schematic diagram of a porosity measurement device provided in a specific embodiment of the present invention.

[0029] Icons: 10-porosity measuring device; 110-first container; 111-ventilation pipe; 113-inlet valve; 120-second container; 121-bracket; 130-connecting pipe; 131-first connecting pipe; 132-second connecting pipe; 133-first vertical section; 134-horizontal section; 135-second vertical section; 140-vacuum pump; 151-first valve; 152-second valve; 153-exhaust valve; 155-pressure sensor. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0031] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] 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.

[0033] In the description of the present invention, it should be noted that if the terms "upper", "lower", "inside", "outside", etc. appear to indicate an orientation or position relationship, they are based on the orientation or position relationship shown in the accompanying drawings, or are the orientation or position relationship in which the product of the invention is usually placed when used. They are only for the convenience of describing the present invention and simplifying the description, and do 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 the present invention.

[0034] In addition, the terms “first”, “second”, etc., if used, are merely used to distinguish between the descriptions and should not be understood as indicating or implying relative importance.

[0035] It should be noted that, in the absence of conflict, the features in the embodiments of the present invention may be combined with each other.

[0036] Soil porosity refers to the percentage of soil pore volume to soil volume. In nature, water and air coexist and fill the soil pore system. Soil pores are the place where water moves and stores. They are also the key factor affecting soil permeability and determining surface runoff and runoff time. Generally, soil pores can be divided into three levels, namely macropores, mesopores and micropores.

[0037] Most of the current soil porosity measurement methods are carried out in the laboratory, that is, the samples need to be brought back to the laboratory for measurement. From collecting soil samples to transporting them back to the laboratory, it is difficult for the samples to be fully preserved, making the final test results less than ideal, and the test cycle is long and the efficiency is low.

[0038] In order to overcome the defects in the prior art, the embodiment of the present invention proposes a porosity measurement device 10 and a porosity measurement method, which can shorten the measurement cycle and improve the measurement efficiency; it has high accuracy, is easy and safe to operate, is easy to carry, and is suitable for field measurement work, without the need to bring samples back to the laboratory for measurement.

[0039] First embodiment

[0040] Please refer to Figure 1The present embodiment provides a porosity measuring device 10, comprising a first container 110, a connecting tube 130, a second container 120 and a vacuum pump 140; the first container 110 is filled with liquid, the connecting tube 130 is used to connect the first container 110 and the second container 120, that is, the first container 110 is connected to one end of the connecting tube 130, and the other end of the connecting tube 130 is connected to the second container 120, the second container 120 is used to place a sample to be measured, and the vacuum pump 140 is connected to the second container 120; a first valve 151 is provided between the vacuum pump 140 and the second container 120, and the first valve 151 can be selectively opened or closed, the first valve 151 is opened to connect the vacuum pump 140 with the second container 120, and the first valve 151 is closed to isolate the vacuum pump 140 from the second container 120. A second valve 152 is provided between the second container 120 and the connecting pipe 130; the second valve 152 can be selectively opened or closed. The second valve 152 is opened to connect the connecting pipe 130 with the second container 120, that is, the first container 110 and the second container 120 are connected to each other; the second valve 152 is closed to isolate the connecting pipe 130 from the second container 120. Optionally, the second valve 152 is provided at one end of the connecting pipe 130 close to the second container 120, which is conducive to the rapid response of the liquid in the first container 110 under the action of the pressure difference. The vacuum pump 140 is used to control the pressure in the second container 120 when the first valve 151 is opened and the second valve 152 is closed. After the sample to be tested is placed in the second container 120, the first container 110 and the second container 120 are first isolated from each other, the vacuum pump 140 is turned on to control the pressure of the second container 120, and then the first container 110 and the second container 120 are connected. Due to the pressure difference between the first container 110 and the second container 120, the liquid level in the first container 110 moves up, and the porosity of the sample to be tested can be calculated by the change of the liquid level. The porosity measuring device 10 has a simple structure, convenient operation, high safety in the measurement process, short measurement cycle, high efficiency, reliable results, and is easy to carry, and is suitable for field measurement work.

[0041] Further, the connecting pipe 130 in this embodiment includes a first connecting pipe 131 and a second connecting pipe 132, one end of the first connecting pipe 131 is connected to the first container 110, the other end of the first connecting pipe 131 is connected to one end of the second connecting pipe 132, and the other end of the second connecting pipe 132 is connected to the second container 120. Among them, the diameter of the first connecting pipe 131 is greater than the diameter of the second connecting pipe 132. Optionally, the diameter of the first connecting pipe 131 is 2cm to 4cm, and the wall thickness is greater than or equal to 1mm to meet the strength requirements and improve the safety of the porosity measuring device 10. The volume of the first connecting pipe 131 is 30ml to 50ml. It should be noted that the porosity measuring device 10 is mainly used to measure the porosity of soil. Of course, the porosity of other objects can also be measured, which is not specifically limited here. Taking the measurement of soil porosity as an example, the diameter and volume of the first connecting pipe 131 can be appropriately replaced according to the measured soil type.

[0042] Optionally, the diameter of the second connecting pipe 132 is 0.5 cm to 1 cm, and the inner wall thickness is 1 mm or more to meet the strength requirements. In this embodiment, the second connecting pipe 132 includes a first vertical section 133, a horizontal section 134, and a second vertical section 135. One end of the first vertical section 133 is connected to the first connecting pipe 131, the other end of the first vertical section 133 is connected to one end of the horizontal section 134, the other end of the horizontal section 134 is connected to one end of the second vertical section 135, and the other end of the second vertical section 135 is connected to the second container 120. Further, the diameter of the first vertical section 133 is 0.6 cm, and the volume of the first vertical section 133 is 10 ml to 20 ml. It is easy to understand that the diameter of the first connecting pipe 131 and the diameter of the second connecting pipe 132 should be as accurate as possible to facilitate the observation of the liquid level, that is, the change in the volume of the rising water. Similarly, the diameter and volume of the second connecting pipe 132 can also be appropriately adjusted or replaced according to the actual soil type to be measured to improve the accuracy of the measurement result. In other optional embodiments, the shape of the second connecting pipe 132 can also be U-shaped or other shapes, such as Figure 2 As shown, Figure 1 The horizontal section 134 is designed to be arc-shaped. Of course, the horizontal section 134 can also be any shape such as V-shaped, M-shaped, spiral, etc., which is not specifically limited here.

[0043] It should be noted that the end of the first connecting pipe 131 close to the first container 110 should extend into the first container 110 and be submerged below the liquid level of the first container 110. In the present embodiment, the first container 110 may be a closed water tank, on which is provided a vent pipe 111 and an air inlet valve 113 provided on the vent pipe 111. When the air inlet valve 113 is opened, the vent pipe 111 is used to connect the water tank with the outside atmosphere; when the air inlet valve 113 is closed, the water tank is in a closed state and isolated from the outside atmosphere. Of course, in other optional embodiments, the first container 110 may be a water tank, that is, it has an opening. In this case, the vent pipe 111 and the air inlet valve 113 may be omitted, and the water tank may be connected with the outside atmosphere. Figure 3 shown.

[0044] The volume of the first container 110 is equal to the volume of the second container 120. Optionally, in this embodiment, the first container 110 and the second container 120 are both in the shape of a cube, the side length of the cube is 8 cm, and the first container 110 and the second container 120 are respectively made of organic glass, and the wall thickness thereof is respectively greater than or equal to 1 cm to meet the strength requirement. Of course, it is not limited to this, and the first container 110 and the second container 120 can also be a cylinder or other shapes, which are not specifically limited here.

[0045] Further, a pressure sensor 155 is provided in the second container 120, and the pressure sensor 155 is used to detect the pressure in the second container 120. In addition, the second container 120 is also provided with an exhaust valve 153, and the exhaust valve 153 is opened to allow the second container 120 to communicate with the outside atmosphere, so as to balance the internal and external air pressures of the second container 120, and avoid the second container 120 being in a vacuum state for a long time and causing damage to the pressure sensor 155 or the second container 120 itself. It is easy to understand that a bracket 121 is provided in the second container 120 for placing the sample to be tested. The second container 120 is also provided with a cover (not shown) that can be opened and closed to facilitate the placement and removal of the sample to be tested.

[0046] The porosity measuring device 10 in this embodiment has a simple and compact structure, a small size, and is easy to carry. It can be used for field soil sampling and measurement in the field, and the samples do not need to be brought back to the laboratory for testing, which shortens the measurement cycle and improves the measurement efficiency and the accuracy of the measurement results. In addition, the production cost is relatively low, the operability is strong, and it does not need to rely on professional personnel for operation, and it is highly safe. In addition, the first connecting tube 131 and the second connecting tube 132 in this embodiment can be replaced and adjusted according to the type of sample to be tested, and have a wide range of applications and flexible use, and have great promotion and application value.

[0047] Second embodiment

[0048] A porosity measurement method provided in an embodiment of the present invention is applied to the porosity measurement device 10 in the aforementioned embodiment to measure the porosity of soil or other objects. In this embodiment, the sample to be measured is soil as an example, and its main steps include:

[0049] First, collect soil samples.

[0050] Specifically, use a shovel to flatten the soil surface at the measurement site to make a platform. Put the ring knife holder on the bladeless end of the ring knife, with the blade of the ring knife facing down, press the ring knife holder handle with balanced force, and drive the ring knife into the soil. It needs to be driven vertically and cannot shake. If the soil is hard and the ring knife is not easy to insert into the soil, you can use a soil hammer to gently hit the ring knife holder handle. When the entire ring knife is pressed into the soil and the soil surface is about to touch the top of the ring knife holder, you can see through the small hole on the ring knife holder cover and stop pressing down. Use a shovel to dig out the soil around the ring knife, cut it off below the ring knife, and leave some excess soil below it; take out the ring knife, turn it over, with the blade facing up, and use a soil cutter to quickly scrape off the soil adhering to the outer wall of the ring knife, and then use the soil cutter to flatten the soil surface from the edge to the middle to make it flush with the blade. When the soil is flush with the bottom edge of the ring knife, put a layer of filter paper on the ring knife and cover the lower cover. Put on the top cover of the ring knife, turn the ring knife over again so that the edge of the knife with the top cover is facing downward, remove the ring knife support, flatten the soil surface without the edge, and put on the bottom cover. The soil sample collection is completed.

[0051] Second, measure the porosity of the soil samples.

[0052] Optionally, the liquid in the first container 110 includes but is not limited to water, and water can be pre-filled in the first container 110; the porosity measuring device 10 is placed on a smooth and flat surface or a workbench surface to ensure that the water in the first container 110 does not overflow, so that the porosity measuring device 10 is in a balanced state to improve the measurement accuracy.

[0053] Before placing the sample to be tested, the sealing of the porosity measuring device 10 is first tested. In detail, the first valve 151 is opened, the second valve 152 is closed, and the exhaust valve 153 and the cover are closed to make the second container 120 in a closed state. Then the vacuum pump 140 is turned on to evacuate the second container 120. The vacuum pump 140 is used to control the pressure in the second container 120 to be a preset pressure, which can be detected by the pressure sensor 155. It should be understood that the preset pressure can be a pressure value at which the air pressure in the second container 120 reaches a stable value, or it can be a pressure value set according to actual needs. In actual operation, after the vacuum pump 140 is turned on for a period of time, the pressure in the second container 120 is stabilized at a certain value and remains constant. The stable pressure value depends on the power of the vacuum pump 140 and is usually used as the preset pressure in the test. Subsequently, the first valve 151 is closed, and the second valve 152 and the air inlet valve 113 of the ventilation pipe 111 on the first container 110 are opened to connect the first container 110 with the outside atmosphere. Check the water level in the first container 110 and record the first liquid level height of the liquid. Optionally, if the water level rises to a certain height and then stabilizes, it proves that the device has good sealing performance, and the volume value of the position of the liquid surface after the water level moves up is recorded as V1. It should be noted that if the first container 110 adopts a water tank, after closing the first valve 151, you only need to open the second valve 152 to check the water level in the first container 110. It is easy to understand that, depending on the preset pressure of the vacuum pump 140, the water level here may rise to the first connecting pipe 131, or it may rise to the second connecting pipe 132.

[0054] Place the sample to be tested in the second container 120; put the sample to be tested on the bracket 121 in the second container 120, close the cover of the second container 120, and after the second container 120 is sealed, close the second valve 152, open the first valve 151, start the vacuum pump 140 to evacuate the second container 120, and after the air pressure in the vacuum pump 140 reaches stability, close the first valve 151. The air pressure value that reaches stability here should be equal to the above-mentioned preset pressure. In this embodiment, the preset pressure can be the stable pressure value of the vacuum pump 140 after working for a period of time.

[0055] Then open the second valve 152 to connect the first container 110 with the second container 120, and keep the first container 110 connected to the outside atmosphere. Since the atmospheric pressure on both sides of the first container 110 and the second container 120 is different, the water level in the first container 110 will rise. After the rising liquid level stabilizes, check the volume value of the water level in the first container 110 after the water level moves up, and record it as V2, that is, record the second liquid level height of the liquid; finally, calculate the soil porosity volume Vpore according to the formula.

[0056] Vhole=(100-(V1-V2)) / 100×100%.

[0057] Among them, 100 is the volume of the conventional ring cutter, (V1-V2) represents the volume of all soil particles in the ring cutter, and (100-(V1-V2)) represents the volume of all soil pores in the ring cutter. In this way, the change in liquid volume can be calculated by the height change of the liquid level in the first container 110 and the known diameter of the connecting pipe 130, thereby calculating the porosity of the sample to be measured. The operation method is simple, does not need to rely on professional operators, has a short measurement cycle, high measurement efficiency, and high safety during the measurement process. In addition, the porosity measuring device 10 has a simple structure, a small size, and is easy to carry. It can be used for measurement in the field without taking the sample back to the laboratory for measurement. It is flexible to use and the measurement results are more accurate and reliable.

[0058] Other contents not mentioned in this embodiment are similar to those described in the first embodiment and will not be described in detail here.

[0059] In summary, the embodiment of the present invention provides a porosity measurement device 10 and a porosity measurement method, which have the following beneficial effects:

[0060] The porosity measuring device 10 has a simple structure, a relatively low manufacturing cost, a small size, is easy to carry, is suitable for field measurement, has a wide range of uses, and is highly flexible. In addition to being used for soil porosity measurement, it can also be used for porosity measurement of other objects. It can also measure repeatedly and has a long service life.

[0061] This porosity measurement method is simple and convenient to operate, does not require professional operation, has strong operability and high safety, can be used not only indoors but also outdoors, and has high flexibility. In addition, the measurement results are accurate and reliable, the measurement cycle is short, and the measurement efficiency is high.

[0062] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. A porosity measuring device, characterized in that: It comprises a first container, a connecting pipe, a second container and a vacuum pump; the first container contains liquid, the first container is connected to one end of the connecting pipe, the other end of the connecting pipe is connected to the second container, the second container is used to place the sample to be tested, and the vacuum pump is connected to the second container; A first valve is provided between the vacuum pump and the second container, and a second valve is provided between the second container and the connecting pipe; the vacuum pump is used to control the pressure of the second container when the first valve is open and the second valve is closed; the volume of the first container is equal to the volume of the second container; A pressure sensor is arranged in the second container.

2. The porosity measuring device according to claim 1, characterized in that: The connecting pipe includes a first connecting pipe and a second connecting pipe, one end of the first connecting pipe is connected to the first container, the other end of the first connecting pipe is connected to one end of the second connecting pipe, and the other end of the second connecting pipe is connected to the second container.

3. The porosity measuring device according to claim 2, characterized in that: The diameter of the first communicating tube is greater than the diameter of the second communicating tube.

4. The porosity measuring device according to claim 3, characterized in that: The diameter of the first connecting tube is 2 cm to 4 cm, and the diameter of the second connecting tube is 0.5 cm to 1 cm.

5. The porosity measuring device according to claim 2, characterized in that: The volume of the first connecting tube is 30 ml to 50 ml.

6. The porosity measuring device according to claim 2, characterized in that: The second connecting pipe includes a first vertical section, a horizontal section and a second vertical section, one end of the first vertical section is connected to the first connecting pipe, the other end of the first vertical section is connected to one end of the horizontal section, the other end of the horizontal section is connected to one end of the second vertical section, and the other end of the second vertical section is connected to the second container.

7. The porosity measuring device according to claim 6, characterized in that: The volume of the first vertical section is 10 ml to 20 ml.

8. The porosity measuring device according to any one of claims 1 to 7, characterized in that: The second container is provided with a degassing valve.

9. A porosity measurement method, characterized in that: The porosity measuring device as claimed in any one of claims 1 to 8 comprises: Before placing the sample to be tested, the first valve is opened, the second valve is closed, and the vacuum pump controls the pressure in the second container to be a preset pressure; closing the first valve, opening the second valve, and recording a first liquid level height of the liquid in the first container; placing a sample to be tested in the second container; Open the first valve, close the second valve, start the vacuum pump to control the pressure in the second container to the preset pressure, close the first valve; open the second valve, and record the second liquid level height of the liquid in the first container; The liquid volume difference is calculated based on the difference between the first liquid level height and the second liquid level height, and the volume difference is the volume of all soil particles in the ring cutter. The volume of all soil pores in the ring cutter is the difference between the volume of the ring cutter and the volume of all soil particles in the ring cutter. The porosity of the sample to be tested is calculated as the ratio of the volume of all soil pores in the ring cutter to the volume of the ring cutter.

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