Device for measuring soil-water characteristic curve of small soil sample

Abstract

The utility model provides a device for measuring a soil-water characteristic curve of a small soil sample, which comprises a sample loading device, the sample loading device is arranged on a top plate of an outflow collecting and measuring device, a gas pressure supply device is arranged at the top of the sample loading device, and a gas supply end of the gas pressure supply device is connected with an output end of a pressure adjusting device. With the adoption of the arrangement mode, the measuring device is high in measuring precision, is particularly suitable for small soil samples, can measure the water yield even if the water yield is very small, and is not influenced by the humidity of an experimental site.

Description

TECHNICAL FIELD

[0001] The utility model relates to the technical field of soil property test, especially a device for measuring the soil water characteristic curve of small soil sample. BACKGROUND

[0002] The soil water characteristic curve is a curve describing the relationship between saturation and matric suction. It reflects the ability of soil to attract water and the distribution characteristics of soil water under different water potentials, and is an important indicator of soil hydrological properties.

[0003] Currently, the following methods are commonly used to measure the soil water characteristic curve: (1) pressure plate instrument method. The principle of this method is to make soil water flow out by increasing external pressure, wait for the water suction force inside the soil to balance with the air pressure, and obtain the soil moisture content under different water suction forces. The water volume measurement system of the pressure plate instrument is composed of a glass tube. During the experiment, the water output gradually decreases with time, and it is difficult for the water volume measurement system to observe the change in water output. It is even less suitable for small soil samples with low moisture content. (2) Filter paper method. The main problem of this method is its low accuracy, especially for small soil samples. The relationship between the hygroscopicity of filter paper and the water characteristics of soil is complex, and it is difficult to accurately reflect the water characteristics of soil.

[0004] Therefore, there is an urgent need for a device for measuring the soil water characteristic curve of small soil samples to solve the above problems. SUMMARY

[0005] The utility model aims at overcoming the above-mentioned shortcomings, and provides a device for measuring the soil water characteristic curve of small soil samples to solve the problems in the background art.

[0006] To solve the above technical problems, the utility model adopts the technical scheme of a device for measuring the soil water characteristic curve of small soil samples, which comprises a sample loading device, the sample loading device is arranged on the top plate of an outflow collection and measurement device, the top of the sample loading device is provided with an air pressure supply device, and the air supply end of the air pressure supply device is connected with the output end of a pressure adjusting device.

[0007] Preferably, the sample loading device comprises a pressure chamber, a sealing cover, a threaded rod and a ceramic soil plate, the bottom end of the threaded rod is arranged on the top plate of the outflow collection and measurement device, and the pressure chamber is jointly locked on the top plate of the outflow collection and measurement device through the sealing cover and the threaded rod.

[0008] Preferably, the ceramic soil plate is arranged at the bottom of the inner cavity of the pressure chamber, and the ceramic soil plate has been saturated.

[0009] Preferably, the outflow collecting and measuring device comprises a flow guide pipe, a narrow-mouthed water collecting bottle, a high-precision electronic scale and a support frame, the high-precision electronic scale is placed in the middle of the bottom plate of the support frame, and the narrow-mouthed water collecting bottle is placed on the high-precision electronic scale.

[0010] Preferably, one end of the flow guide pipe penetrates through the top plate of the support frame and communicates into the bottom plate of the pressure chamber, and the other end of the flow guide pipe is connected to the bottle mouth of the narrow-mouthed water collecting bottle.

[0011] Preferably, a sealing plug is arranged at the bottle mouth of the narrow-mouthed water collecting bottle.

[0012] Preferably, a saturated lead wire is arranged in the flow guide pipe to increase the smoothness of water outflow and prevent water from accumulating in the water pipe.

[0013] Preferably, the air pressure supply device comprises an air compressor, an air compressor pressure gauge and an air inlet pipe, one end of the air inlet pipe is connected to the air outlet of the air compressor, and the other end of the air inlet pipe is connected to the air inlet of the pressure regulating valve.

[0014] Preferably, the pressure regulating device comprises a pressure regulating valve and a pressure gauge for observing the pressure value, and the bottom pipe of the pressure regulating valve penetrates through the sealing cover and enters the pressure chamber.

[0015] The utility model has the following beneficial effects:

[0016] 1. The measuring device of the utility model has high measuring precision, is particularly suitable for small soil samples, can measure even if the water outflow is very small, and is not affected by the humidity of the experimental site.

[0017] 2. The saturated lead wire arranged in the flow guide pipe of the utility model can increase the smoothness of water outflow and prevent water from accumulating in the water pipe, thereby reducing the experimental error. BRIEF DESCRIPTION OF DRAWINGS

[0018] Fig. 1 It is a whole structure schematic view of the utility model;

[0019] Fig. 2 It is a structure schematic view of the outflow collecting device of the utility model. DETAILED DESCRIPTION

[0020] The utility model will be further described below in combination with the drawings and examples:

[0021] As Figs. 1-2The utility model provides a kind of device for measuring small soil sample soil-water characteristic curve, including sample loading device 1, the sample loading device 1 is arranged on the top plate of effluent collection and measuring device 2, the top of the sample loading device 1 is equipped with gas pressure supply device 3, and the gas supply end of the gas pressure supply device 3 is connected with the output end of pressure regulating device 4.The sample loading device 1 is used to place the soil sample to be measured, which is connected with the pressure supply device 3 above and connected with the effluent collection and measuring device 2 below;The gas pressure supply device 3 provides gas pressure for the experiment;The pressure regulating device 4 can adjust different pressure values according to the experimental requirements, realize low pressure and high pressure conversion.

[0022] Preferably, the sample loading device 1 includes a pressure chamber 101, a sealing cover 102, a threaded rod 103, and a clay plate 104, the bottom end of the threaded rod 103 is arranged on the top plate of the effluent collection and measuring device 2, and the pressure chamber 101 is locked on the top plate of the effluent collection and measuring device 2 by the sealing cover 102 and the threaded rod 103 to ensure the air tightness of the pressure chamber.

[0023] Preferably, the clay plate 104 is arranged at the bottom of the inner cavity of the pressure chamber 101, and the clay plate 104 has been saturated.

[0024] Preferably, the effluent collection and measuring device 2 includes a flow guide pipe 201, a narrow-mouthed water collection bottle 202, a high-precision electronic scale 203, and a support frame 206, the high-precision electronic scale 203 is placed in the middle of the bottom plate of the support frame 206, and the narrow-mouthed water collection bottle 202 is placed on the high-precision electronic scale 203.

[0025] Preferably, one end of the flow guide pipe 201 penetrates through the top plate of the support frame 205 and communicates into the bottom plate of the pressure chamber 101, and the other end of the flow guide pipe 201 is connected to the bottle mouth of the narrow-mouthed water collection bottle 202. By measuring the soil moisture content under different pressure values, the saturation of the soil can be calculated, and the soil-water characteristic curve of the soil sample can be obtained.

[0026] Preferably, a sealing plug 204 is arranged at the bottle mouth of the narrow-mouthed water collection bottle 202 to prevent the influence of humidity on the experimental results.

[0027] Preferably, a saturated lead 205 is arranged in the flow guide pipe 201 to increase the smoothness of water flow and prevent water accumulation in the water pipe.

[0028] Preferably, the gas pressure supply device 3 includes an air compressor 301, an air compressor pressure gauge 302, and an air inlet pipe 303, one end of the air inlet pipe 303 is connected to the air outlet of the air compressor 301, and the other end of the air inlet pipe 303 is connected to the air inlet of the pressure regulating valve 401.

[0029] Preferably, the pressure regulating device 4 comprises a pressure regulating valve 401 and a pressure gauge 402 for observing pressure value, the pressure regulating valve 401 is penetrated into the pressure chamber 101 through the sealing cover 102. Different pressure values can be regulated by the pressure regulating valve 401, and the conversion between low pressure and high pressure is realized to meet the experimental requirements.

[0030] The working principle of the embodiment is as follows:

[0031] In use, the saturated clay plate 104 and the soil sample are sequentially placed into the pressure chamber 101, then the sealing cover 102 is installed, the threaded rod 103 is tightened, the saturated lead wire 205 flow guide pipe 202 is connected to the narrow-mouthed water collecting bottle 202, the sealing plug 204 is clamped, the high-precision electronic scale 203 is zeroed, then the air compressor 301 is started, the pressure regulating valve 401 is adjusted to the preset value, the test is started, when the flow guide pipe no longer flows, the value of the high-precision balance 203 is read, and the pressure value and the water value at this time are recorded.

[0032] The above embodiment is only a preferred technical solution of the utility model, and should not be regarded as a limitation of the utility model. The protection scope of the utility model should be the technical solution recorded in the claims, and the equivalent replacement solution of the technical features recorded in the claims is the protection scope. That is, the equivalent replacement improvement within the scope is also within the protection scope of the utility model.

Claims

1. A device for measuring the soil water characteristic curve of a small soil sample, comprising a sample loading device (1), characterized in that, The sample loading device (1) is arranged on the top plate of the outflow collection and measurement device (2), and the top of the sample loading device (1) is provided with a gas pressure supply device (3), and the gas supply end of the gas pressure supply device (3) is connected with the output end of a pressure adjusting device (4).

2. A device for measuring the soil water characteristic curve of a small soil sample according to claim 1, characterized in that The sample loading device (1) comprises a pressure chamber (101), a sealing cover (102), a threaded rod (103) and a clay plate (104), the bottom end of the threaded rod (103) is arranged on the top plate of the outflow collection and measurement device (2), and the pressure chamber (101) is jointly locked on the top plate of the outflow collection and measurement device (2) through the sealing cover (102) and the threaded rod (103).

3. A device for measuring the soil water characteristic curve of a small soil sample according to claim 2, characterized in that The clay plate (104) is arranged at the bottom of the inner cavity of the pressure chamber (101), and the clay plate (104) has been subjected to saturation treatment.

4. The apparatus for measuring the soil water characteristic curve of a small soil sample according to claim 1, wherein, The outflow collection and measurement device (2) comprises a flow guide pipe (201), a narrow-mouthed water collecting bottle (202), a high-precision electronic scale (203) and a support frame (206), the high-precision electronic scale (203) is placed in the middle of the bottom plate of the support frame (206), and the narrow-mouthed water collecting bottle (202) is placed on the high-precision electronic scale (203).

5. A device for measuring the soil water characteristic curve of a small soil sample according to claim 4, characterized in that One end of the flow guide pipe (201) penetrates through the top plate of the support frame (206) and communicates into the bottom plate of the pressure chamber (101), and the other end of the flow guide pipe (201) is connected to the bottle mouth of the narrow-mouthed water collecting bottle (202).

6. A device for measuring the soil water characteristic curve of a small soil sample according to claim 5, characterized in that A sealing plug (204) is arranged at the bottle mouth of the narrow-mouthed water collecting bottle (202).

7. The apparatus of claim 4, wherein, The flow guide pipe (201) is provided with a lead wire (205) subjected to saturation treatment, so as to increase the smoothness of water flow and prevent water accumulation in the water pipe.

8. The apparatus of claim 1, wherein: The gas pressure supply device (3) comprises an air compressor (301), an air compressor pressure gauge (302) and an air inlet pipe (303), one end of the air inlet pipe (303) is connected with the air outlet of the air compressor (301), and the other end of the air inlet pipe (303) is connected with the air inlet of a pressure regulating valve (401).

9. The apparatus of claim 1, wherein: The pressure regulating device (4) comprises the pressure regulating valve (401) and a pressure gauge (402) for observing the pressure value, and the bottom pipe of the pressure regulating valve (401) penetrates through the sealing cover (102) and enters the pressure chamber (101).

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