A device for measuring the density of water film on the surface of soil particles and the specific gravity of soil

Abstract

The application provides a device for measuring the density of water film on the surface of soil particles and the specific gravity, which comprises a vacuum saturation cylinder with a sealing cover arranged at the upper end, an electronic balance arranged in the saturation cylinder, a magnetic stirrer and a temperature control box with an open top arranged above the electronic balance in sequence, a narrow-neck glass volumetric flask arranged in the temperature control box, a temperature controller and benzyl silicone oil, and a camera and a computer data acquisition system; the narrow-neck glass volumetric flask comprises an upper part with a narrow neck and a scale and a lower part communicated with a liquid supplementing pipe, the upper part and the lower part are separable and can be connected by a sealing washer, the narrow neck and the scale of the narrow-neck glass volumetric flask extend upwards beyond the top of the temperature control box and the vacuum saturation cylinder, the liquid level is photographed in real time by the camera and the data is transmitted to the computer data acquisition system for analysis and calculation. The application provides a new way for measuring the density of water film on the surface of soil particles and the specific gravity.

Description

Technical Field

[0001] This invention relates to geotechnical engineering testing instruments, specifically to a device for measuring the density and specific gravity of water film on the surface of soil particles. Background Technology

[0002] Clay minerals possess surface charges due to isomorphous substitution, ion adsorption, and lattice breaking. The small size of clay particles, coupled with their large cation exchange capacity and specific surface area, results in strong water sensitivity, leading to the adsorption of water films on their surfaces. The interaction between the soil, water, and electrolyte system influences the density and properties of the water film on the particle surface, affecting the physicochemical properties of the soil. Different water film densities result in solid / semi-solid and plastic / flowable states, leading to complex physical and mechanical properties. The density and properties of the water film on clay particle surfaces are related to environmental temperature, soil mineral composition and morphology, and pore fluid medium. Currently, there is a lack of devices capable of measuring the density of the water film on the surface of soil particles with different mineral compositions under varying temperature conditions. Therefore, a device for measuring the density of the water film on the surface of soil particles is needed in this field.

[0003] On the other hand, the existing method of measuring the specific gravity of soil particles using a specific gravity bottle is cumbersome and prone to large errors. Significant errors can occur when the bottle is tightly sealed and liquid overflows from the stopper hole, especially since cleaning the bottle after kerosene spillage is troublesome and residue can easily affect the accuracy of the measurement. Furthermore, when measuring the mass of the specific gravity bottle at different temperatures, it is removed from the constant-temperature water bath, which is not precise enough, and the high temperature of the sand bath increases the risk. Therefore, there is a need in this field for a new device for measuring the specific gravity of soil particles. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings and deficiencies of the existing technology and to provide a device for measuring the density and specific gravity of water film on the surface of soil particles, which is applicable to all soils, especially clay particles such as expansive soil.

[0005] This invention provides an apparatus for measuring the density and specific gravity of water film on the surface of soil particles. The apparatus includes a vacuum saturation cylinder (5) with a sealed cap at the top, an electronic balance (2) inside the vacuum saturation cylinder (5), a magnetic stirrer (9) and a temperature control box (7) with a top opening arranged sequentially above the electronic balance (2), a narrow-necked glass volumetric flask (4) inside the temperature control box (7), a temperature controller (8), and benzyl silicone oil for heat conduction. The apparatus also includes a camera (1) and a computer data acquisition system (11). The narrow-necked glass volumetric flask (4) includes an upper part with a narrow neck and graduations and a lower part connected to a liquid replenishment tube (6). The upper and lower parts are separable and can be sealed using a sealing gasket. The narrow neck and graduations of the narrow-necked glass volumetric flask (4) extend upward beyond the top of the temperature control box (7) and the vacuum saturation cylinder (5), and the camera (1) captures the liquid level in real time and transmits the data to the computer data acquisition system (11) for analysis and calculation.

[0006] In one specific embodiment, the temperature controller (8) includes an electric heating tube, and the device also includes a temperature sensor (3) disposed in benzyl silicone oil inside the temperature control box (7), preferably the temperature sensor has a measurement accuracy of 0.01℃.

[0007] In one specific embodiment, the device further includes a vacuum pump (10) connected to a valve on the sealing cover of the vacuum saturation cylinder (5) and used to evacuate the vacuum saturation cylinder (5).

[0008] In one specific embodiment, a plastic buckle is also fixedly provided on the upper and / or lower part of the narrow-necked glass volumetric flask (4) for locking and fixing the upper and lower parts together; preferably, the plastic buckle is bonded and fixed to the upper and / or lower part of the narrow-necked glass volumetric flask (4).

[0009] In one specific embodiment, the electronic balance (2), temperature controller (8) and temperature sensor (3) are all electrically connected to the computer data acquisition system (11). The temperature controller (8) is used to dynamically control the temperature of the benzyl silicone oil, and the temperature sensor (3) is used to accurately measure the real-time temperature of the benzyl silicone oil.

[0010] In one specific embodiment, the narrow-necked glass volumetric flask (4) is also fitted with a magnet, and the volume of the magnet has been taken into account when designing the scale of the narrow-necked glass volumetric flask (4).

[0011] In one specific embodiment, the top height of the liquid replenishment tube (6) is higher than the bottom height of the narrow neck of the narrow-necked glass volumetric flask (4), and lower than the top height of the narrow neck of the narrow-necked glass volumetric flask (4).

[0012] In this invention, because the neck of the narrow-necked glass volumetric flask (4) is small enough, liquid cannot be directly injected into the flask from the neck. This invention uses a syringe to inject liquid into the flask from the top of the liquid replenishment tube (6), which can also prevent liquid from sticking to the wall at the neck and affecting the liquid volume reading.

[0013] In one specific embodiment, the lower part of the narrow-necked glass volumetric flask (4) is spherical.

[0014] This invention provides an integrated intelligent device for measuring the density and specific gravity of water film on the surface of soil particles. Utilizing a high-precision electronic balance and camera, it accurately measures the mass and volume of the test sample and provides an accurate, temperature-controlled testing environment. This offers a new approach to measuring the density and specific gravity of water film on the surface of soil particles, providing a reliable basis for solving geotechnical engineering problems and ensuring the accuracy and practicality of the test results. The device is characterized by its simple operation, affordability, high intelligence, and high accuracy. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the device used in this invention to measure the density and specific gravity of the water film on the surface of soil particles.

[0016] In the diagram: 1-Camera; 2-Electronic balance; 3-Temperature sensor; 4-Necked glass volumetric flask; 5-Vacuum saturation cylinder; 6-Liquid replenishment tube; 7-Temperature control box; 8-Temperature controller; 9-Magnetic stirrer; 10-Vacuum pump; 11-Computer data acquisition system. Detailed Implementation

[0017] To provide a device for measuring the density and specific gravity of the water film on the surface of soil particles, the basic idea of ​​this invention is as follows: Soil particles are placed in a glass volumetric flask, water or neutral liquid kerosene is added, residual gas inside the soil particles is removed by oil bath and / or vacuuming, and the soil and liquid are mixed evenly by magnetic stirring. Finally, the mass and volume of the soil-liquid mixture in the glass volumetric flask are determined by electronic balance and camera, respectively, and the density and specific gravity of the water film on the surface of the soil particles are finally determined.

[0018] It also features original designs in the following three aspects:

[0019] 1. This device uses benzyl silicone oil (KF-54) as the heat transfer oil. Benzyl silicone oil has properties such as heat resistance, oxidation resistance, and low-temperature resistance. The temperature control system can adjust the system temperature range from room temperature to 300℃, avoiding the uneven heating and high-temperature hazards associated with sand baths. Simultaneously, this device can also perform vacuuming. It can measure the density and specific gravity of the water film on the surface of soil particles at different temperatures, with temperature accuracy within 0.01℃.

[0020] 2. The computer data acquisition system can automatically read the readings on the narrow-necked glass bottle and accurately measure the volume of the volumetric flask to an accuracy of 0.001 ml; it can also automatically read the mass of the volumetric flask. After determining the volume and mass, the system automatically outputs the specific gravity of the soil particles or the density of the water film on the particle surface through a pre-programmed calculation.

[0021] 3. The test apparatus contains a magnetic stirrer, which can accelerate the mixing of soil particles and liquid, and accelerate the removal of residual gas.

[0022] 4. The narrow-necked glass volumetric flask is a two-part design. The upper part can be separated to easily and quickly add soil particles into the flask. The smallest graduation on the narrow neck is 0.001 ml, allowing for precise measurement of the flask's volume. After the upper and lower parts are tightly connected, the liquid can be added through the liquid replenishment tube to fill the flask to the graduation mark. This not only allows for simple and quick replenishment of liquid but also avoids liquid residue on the walls after adding liquid from the neck, which could affect the accuracy of the test.

[0023] The objective of this invention is achieved as follows:

[0024] The object to be tested, i.e., the soil sample, is placed in the narrow-necked glass volumetric flask 4 of this apparatus;

[0025] This device includes a magnetic stirring temperature control and measurement system, a vacuum volume measurement system, and an image acquisition system;

[0026] The magnetic stirring temperature control measurement system includes a magnetic stirrer 9, a temperature controller 8, a temperature control box 7, a temperature sensor 3, and an electronic balance 2.

[0027] The vacuum volume measurement system includes a vacuum pump 10, a vacuum saturation cylinder 5, and a narrow-necked glass volumetric flask 4. The narrow-necked glass volumetric flask includes separable upper and lower parts: an upper part with a graduated narrow neck and a circular lower part with a liquid replenishment tube 6. The total capacity is 150 ml, and the smallest graduation on the narrow neck is 0.001 ml.

[0028] The image acquisition system includes a camera 1 and a computer data acquisition system 11.

[0029] The interactions of the particle-water-electrolyte system on the surface of sandy and silty soil particles are generally weak, so distilled water can be used to measure their specific gravity. However, the interactions of the particle-water-electrolyte system on the surface of silty clay and clayey soil particles are generally strong, so neutral liquid kerosene is used to measure their specific gravity. The density of the water film on the particle surface of all soil types is measured using kerosene. The main methods and procedures are as follows:

[0030] (1) Specific gravity measurement of sandy and silty soils

[0031] Separate the upper and lower parts of the narrow-necked glass volumetric flask. Place 30g of dried soil sample into the lower part, and then fasten the upper and lower parts together. Inject the measuring liquid into the volumetric flask through the liquid replenishment tube 6 using a syringe, and then close the replenishment tube switch. For sand and silt, use distilled water. The volume of the liquid should slightly exceed the connection between the upper and lower parts of the volumetric flask. The volumetric flask is placed and secured in a temperature-controlled chamber 7 containing benzyl silicone oil (KF-54) for heat transfer. The magnetic stirrer 9 is turned on to rapidly mix the soil particles and the measuring liquid. The temperature sensor 8 is then turned on to raise the temperature of the heat transfer oil to more than 50°C above the boiling point of the measured liquid, causing the liquid in the glass volumetric flask to boil for at least 1 hour. The temperature sensor 3 is then turned on to measure the temperature of the heat transfer oil in the temperature-controlled chamber 7, with a measurement accuracy of 0.01°C. The temperature of the temperature-controlled chamber is then lowered until the volumetric flask has cooled and stabilized, and the upper part of the suspension has become clear. Liquid is then refilled into the glass volumetric flask through the liquid replenishment tube 6 until the liquid volume reaches the measurable range on the narrow neck. The graduations on the narrow neck are then read using the camera 1. The mass of the temperature-controlled chamber 7 and the magnetic stirrer 9 has already been measured using an electronic balance 2, and the mass of the empty glass volumetric flask 4 and the magnetic stirrer are known. The loaded mass of the narrow-necked glass volumetric flask is measured using the electronic balance 2, and finally, the specific gravity of the soil is obtained by processing the data using the computer data acquisition system 11.

[0032] (2) Measurement of the specific gravity of silty clay and clay and the water film density of all soil types

[0033] Separate the upper and lower parts of the narrow-necked glass volumetric flask. Place 30g of soil sample in the lower part. Inject the measuring liquid into the volumetric flask through the liquid replenishment tube 6 using a syringe, then close the replenishment tube switch. For silty clay and clay types, use kerosene. The liquid volume should be below the connection point between the upper and lower parts of the volumetric flask. Place the volumetric flask in a temperature control box 7 containing benzyl silicone oil (KF-54) and secure it. The water level of the heat transfer oil should be below the connection point of the volumetric flask. Turn on the magnetic stirrer 9 to mix the liquid and soil evenly. Cover the vacuum saturation cylinder 5 with the lid, close the vent switch on the left side of the lid, and open the switch on the right side of the lid connecting to the vacuum pump 10. Evacuate for at least 1 hour to ensure that the mixture no longer contains residual gas. After evacuation, turn off the vacuum pump, open the vacuum saturation cylinder 5, and fasten the upper and lower parts of the volumetric flask together. Then, inject liquid into the glass volumetric flask through the liquid replenishment tube 6 until the liquid volume reaches the measurable range on the narrow neck. To measure the water film density under different temperature conditions, turn on the temperature controller 8, set it to the rated measurement temperature, and heat the kerosene to the measurement temperature using heat transfer oil. The mass of the temperature control box 7 and the magnetic stirrer 9 has already been measured using the electronic balance 2, and the empty mass of the narrow-necked glass volumetric flask 4 is known. The loaded mass of the glass volumetric flask is measured using the electronic balance 2. Finally, the specific gravity of the dried soil or the water film density on the surface of the soil particles under water film conditions is obtained through processing by the computer data acquisition system 11.

[0034] Therefore, the benzyl silicone oil (KF-54) heat-conducting oil described in this invention can, on the one hand, degas the liquid and soil within it by combining heating and magnetic stirring; on the other hand, it can measure the specific gravity of dried soil at different temperatures or the water film density on the surface of soil particles under conditions containing a water film by setting a specific temperature. This invention can use only the benzyl silicone oil (KF-54) heat-conducting oil without using vacuum to heat the liquid to 50°C above its boiling point to degas the liquid and soil. However, because the boiling point of kerosene is higher than that of water, the process of heating kerosene to 50°C above its boiling point using heat-conducting oil is relatively slow. Therefore, vacuum is generally used instead of this method to degas the soil and liquid, or a combination of vacuum and other methods is used. When the liquid is water, generally only the benzyl silicone oil (KF-54) heat-conducting oil is used without using vacuum to heat the water to 50°C above its boiling point to degas the water and soil, because this operation method is simpler and more convenient. In addition, when using only benzyl silicone oil (KF-54) heat transfer oil without vacuuming to vent the kerosene, a kerosene product with a lower boiling point is generally selected, such as kerosene with a boiling point between 110 and 150°C.

[0035] The specific calculation method is as follows:

[0036] (1) Calculation method for specific gravity of dried soil

[0037] When measuring the specific gravity of soil, the specific gravity of soil particles is calculated using formula (1) when distilled water is used as the measuring liquid. When kerosene is used as the measuring liquid, the specific gravity of soil particles is calculated using formula (2). The specific gravity of kerosene is calculated without soil, as shown in formula (3). The specific specific gravity test results of different soil samples are shown in Table 1.

[0038] In this invention, since the distilled water material is consistent and fixed, the density of free water at temperature T can be determined by consulting a database; the density of water at 25°C is found to be 0.9970 g / cm³. 3 However, kerosene varies in composition, therefore its specific gravity G at temperature T also varies. kT Actual measurement is required, specifically using the following formula (3). Since soil was not added when measuring the specific gravity of kerosene in formula (3), V represents the measured volume of liquid kerosene. The specific gravity G of the dried soil at temperature T in Table 1 is measured. sT Previously, the specific gravity G of the kerosene used at a temperature of 25℃ was measured. kT It is 0.7857.

[0039]

[0040]

[0041]

[0042] In the formula, G sT —Specific gravity of the dried soil at temperature T, m —Total mass of bottle, liquid, and soil, accurate to 0.001g; m d —The mass of the dried soil, accurate to 0.001g; m b —The mass of the empty bottle, accurate to 0.001g; V —The measured volume of liquid and soil; ρ wT —The density of free water at temperature T; G kT —Specific gravity of kerosene at temperature T.

[0043] Table 1. Specific gravity measurement results of different soil samples

[0044]

[0045] (2) Method for measuring the density of water molecules (water film density) on the surface of soil particles containing moisture

[0046] To measure the density of water molecules on the surface of soil particles, only kerosene was used as the measuring liquid. The density of water molecules on the particle surface was calculated as shown in formula (4):

[0047]

[0048]

[0049] In the formula, ρ wbT —Density of the water film on the surface of soil particles at temperature T; ρ wT —Density of free water at temperature T; m d —Dried soil mass, accurate to 0.001g; w —Soil sample moisture content; ΔV —Difference between water film and free water volume for the same mass; V —Total measured volume of soil and kerosene; m —Total measured mass of soil, kerosene, and glass bottle, accurate to 0.001g; m b —The mass of the empty bottle, accurate to 0.001g; G kT —Specific density of kerosene at temperature T; G sT —Specific gravity of soil.

[0050] Table 2. Measurement results of water film density on soil particle surface under different moisture contents.

[0051]

[0052]

[0053] Clay 1 was selected for water film density tests at different moisture contents at 25℃. Table 1 shows its dry soil specific gravity as G. sT =2.74, the specific gravity G of the kerosene used in Table 2 at 25°C kT =0.7857, the density of water is ρ wT =0.997, and the specific water film density measurement results are shown in Table 2. The soil sample moisture content is known in Table 2.

[0054] The above description, in conjunction with specific preferred embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various simple deductions and substitutions can be made without departing from the inventive concept, and all such modifications and substitutions should be considered within the scope of protection of the present invention.

Claims

1. An apparatus for measuring the density and specific gravity of water film on the surface of soil particles, the apparatus comprising a vacuum saturation cylinder (5) with a sealed cap at the top, an electronic balance (2) disposed within the vacuum saturation cylinder (5), a magnetic stirrer (9) disposed sequentially above the electronic balance (2), a temperature control box (7) with an open top, a narrow-necked glass volumetric flask (4) disposed within the temperature control box (7), a temperature controller (8), and benzyl silicone oil for heat conduction, the apparatus further comprising a camera (1) and a computer data acquisition system (11); the narrow-necked glass volumetric flask (4) comprises an upper part with a narrow neck and graduations and a lower part connected to a liquid replenishment tube (6), the upper and lower parts being separable and capable of being sealed. A gasket is used for sealing connection. The narrow neck and scale of the narrow-necked glass volumetric flask (4) extend upward beyond the top of the temperature control box (7) and the vacuum saturation cylinder (5), and the liquid level is captured in real time by the camera (1) and the data is transmitted to the computer data acquisition system (11) for analysis and calculation. The device also includes a vacuum pump (10) connected to the valve on the sealing cover of the vacuum saturation cylinder (5) and used to evacuate the vacuum saturation cylinder (5). The top height of the liquid replenishment tube (6) is higher than the bottom height of the narrow neck of the narrow-necked glass volumetric flask (4) and lower than the top height of the narrow neck of the narrow-necked glass volumetric flask (4). The lower part of the narrow-necked glass volumetric flask (4) is spherical.

2. The device for measuring the density and specific gravity of the water film on the surface of soil particles according to claim 1, characterized in that, The temperature controller (8) includes an electric heating element, and the device also includes a temperature sensor (3) disposed in benzyl silicone oil inside the temperature control box (7).

3. The device for measuring the density and specific gravity of the water film on the surface of soil particles according to claim 2, characterized in that, The temperature sensor has a measurement accuracy of 0.01℃.

4. A device for measuring the density and specific gravity of water film on the surface of soil particles according to any one of claims 1 to 3, characterized in that, Plastic buckles are also fixedly provided on the upper and lower parts of the narrow-necked glass volumetric flask (4) to lock and fix the upper and lower parts together.

5. The device for measuring the density and specific gravity of the water film on the surface of soil particles according to claim 4, characterized in that, The plastic buckle is glued and fixed to the upper and lower parts of the narrow-necked glass volumetric flask (4).

6. A device for measuring the density and specific gravity of water film on the surface of soil particles according to any one of claims 1 to 3, characterized in that, The electronic balance (2), temperature controller (8) and temperature sensor (3) are all electrically connected to the computer data acquisition system (11). The temperature controller (8) is used to dynamically control the temperature of the benzyl silicone oil, and the temperature sensor (3) is used to accurately measure the real-time temperature of the benzyl silicone oil.

7. A device for measuring the density and specific gravity of water film on the surface of soil particles according to any one of claims 1 to 3, characterized in that, The narrow-necked glass volumetric flask (4) is also equipped with a magnet, and the volume of the magnet has been taken into account when designing the scale of the narrow-necked glass volumetric flask (4).

Images