CN108287121B - Device and method for measuring moisture characteristic curve of soil dehumidification and moisture absorption process - Google Patents

Abstract

The invention provides a device and method for measuring the moisture characteristic curve of soil dehumidification and moisture absorption process. The device comprises a ring knife, two tensiometers, a measuring instrument, a clay plate and a first vessel. The side wall of the ring knife is provided with a Two openings located at different heights of the side wall, the ring knife is set outside the soil to be measured; two tensiometers are configured to be respectively adapted to be inserted into the soil through the two openings and to measure the tension of the soil; clay The plate is placed in the first vessel for supporting the ring knife; the first vessel is configured so that when the moisture characteristic curve of the soil moisture absorption process is measured, the water in the first vessel and the end surface of the clay plate are always kept at the same height; the measuring instrument It is configured to measure and record the weight of the ring knife and the soil corresponding to a plurality of preset times, or the weight of the ring knife, the first vessel, the clay plate and the soil, and record the indications of the two tensiometers corresponding to the preset times. The invention can be used to determine the soil moisture characteristic curve corresponding to the two processes of soil moisture absorption and dehumidification.

Description

Device and method for measuring moisture characteristic curve of soil dehumidification and moisture absorption process

technical field

The invention relates to the technical field of farmland water conservancy scientific research instruments, in particular to a device and a method for measuring moisture characteristic curves of soil dehumidification and moisture absorption processes.

Background technique

Soil water suction varies with soil moisture content, and the relationship curve is called soil moisture characteristic curve. The soil moisture characteristic curve reflects the relationship between soil moisture energy and quantity, and is an indispensable and important parameter for studying soil hydrodynamic properties, and has important guiding significance in production practice. For the same soil, even under the same conditions, the moisture characteristic curves measured by the soil dehumidification (from wet to dry) process and the soil hygroscopicity (from dry to wet) process are different. This phenomenon is called "hysteresis" ". When studying the soil infiltration process of alternating dry and wet, especially for the sandy soil, the water characteristic curve corresponding to the two processes of soil dehumidification and moisture absorption can be used to obtain a better simulation effect. Therefore, it is necessary to use the moisture characteristic curve corresponding to the two processes of soil dehumidification and moisture absorption of the instrument.

At present, the ku-pf unsaturated hydraulic conductivity measurement system is usually used to determine the soil moisture characteristic curve. The ku-pf unsaturated hydraulic conductivity measurement system includes a ring knife for placing soil, a seat plate, two tensiometers and a measuring instrument electrically connected to the two tensiometers. One opening is above the other opening. During measurement, place the wet soil to be tested in the ring knife, then insert two tensiometers into the wet soil through an opening of the ring knife respectively, and the measuring instrument measures and records the corresponding ring knife and soil at the preset time. weight and record the readings on both tensiometers. When the indications of the two tensiometers no longer change, end the measurement. According to the data recorded by the analyzer, the moisture characteristic curve of the soil dehumidification process was obtained.

In the process of realizing the present invention, the present inventor found that there are at least the following problems in the prior art:

The existing ku-pf unsaturated hydraulic conductivity measurement system can only measure the moisture characteristic curve of the soil dehumidification process, but cannot measure the moisture characteristic curve of the soil moisture absorption process.

SUMMARY OF THE INVENTION

In view of this, the present invention provides a device and method for measuring the moisture characteristic curve of soil dehumidification and moisture absorption process, which can measure the moisture characteristic curve corresponding to the two processes of soil dehumidification and moisture absorption.

Specifically, it includes the following technical solutions:

In the first aspect, the embodiment of the present invention provides a device for measuring the moisture characteristic curve of soil dehumidification and moisture absorption process, including a ring knife, two tensiometers, a measuring instrument, a clay plate and a first vessel, wherein,

The side wall of the ring knife is provided with two openings, the two openings are located at different heights of the side wall, and the ring knife is configured to be sleeved outside the soil to be measured;

The two tensiometers are configured to be respectively adapted to be inserted into the soil through the two openings and to measure the tension of the soil

the clay plate is placed in the first vessel for supporting the ring knife;

The first vessel is configured such that when the moisture characteristic curve of the soil moisture absorption process is determined, the water in the first vessel and the upper end surface of the clay plate are always kept at the same height;

The measuring instrument is configured to measure and record the weight of the ring knife and the soil in the ring knife, or the ring knife, the first vessel, the clay plate and the The weight of the soil in the ring knife is recorded, and the indications of the two tension meters corresponding to the plurality of preset moments are recorded.

Optionally, the device further comprises a sealed second vessel, the first vessel is in communication with the second vessel, and the water in the second vessel is adapted to flow into the first vessel;

A conduit is arranged in the second vessel, and one end of the conduit extends to the outside of the second vessel;

The upper end of the first vessel is open, the conduit and the first vessel constitute a communication device, the water in the conduit and the upper end surface of the clay plate are always kept at the same height, and the water level of the second vessel is The water between the bottoms of the conduits is used to supply the soil moisture within the ring knife for moisture absorption.

Optionally, a liquid outlet is formed on the side wall of the second vessel, and a liquid inlet is formed on the side wall of the first vessel, and the liquid outlet is communicated with the liquid inlet through a pipeline.

Optionally, a switch is provided on the pipeline.

Optionally, the ring knife is configured such that when placed on the clay plate, two of the openings are located above the first vessel.

Optionally, the measuring instrument is provided with a seat plate for placing the ring knife.

Optionally, the device further includes a screen bottom plate for placing the ring knife and the soil to be tested, and placed in water, so that the soil to be tested absorbs water.

In a second aspect, the present invention also provides a method for determining the moisture characteristic curve of soil dehumidification and moisture absorption process, and the device for determining the moisture characteristic curve of soil dehumidification and moisture absorption process described in any one of the first aspect is obtained by To achieve, the method includes:

The ring knife is set outside the saturated soil and placed on the measuring instrument;

Insert the two tensiometers into the soil in the ring knife through the corresponding openings respectively;

The measuring instrument is used to measure and record the weight of the ring knife and the soil in the ring knife corresponding to a plurality of preset moments, and record the indications of the two tension meters corresponding to the plurality of preset moments , until the indications of the two tensiometers no longer change, and the dehumidified soil is obtained;

The ring knife and the dehumidified soil are placed on the clay plate in the first vessel, and the water in the first vessel and the upper end surface of the clay plate are always kept at the same height;

The measuring instrument is used to measure and record the weight of the ring knife and the soil in the ring knife corresponding to a plurality of preset moments, and record the indications of the two tension meters corresponding to the plurality of preset moments , until the readings of the two tensiometers no longer change.

Optionally, before inserting the two tensiometers into the soil in the ring knife through the corresponding openings, the method further includes: calibrating the two tensiometers.

Optionally, before the ring knife is set outside the soil soaked in water and placed on the measuring instrument, the method further includes:

The ring knife is sleeved outside the soil to be tested and placed on the screen chassis, and then the screen chassis is placed in water, keeping the height of the water lower than the opening below the ring knife, Until the upper end of the soil to be tested overflows with water.

The beneficial effects of the technical solutions provided by the embodiments of the present invention:

The device and method for measuring the moisture characteristic curve of the soil dehumidification and moisture absorption process provided by the embodiment of the present invention, by setting two openings on the ring knife, so that the two tensiometers can be inserted into the to-be-detected through the corresponding openings respectively. The tension of the soil is measured in the soil; the ring knife and the soil absorbing water are placed on the measuring instrument, so that the measuring instrument measures and records the weight of the soil corresponding to the ring knife and the soil in the ring knife at multiple preset moments in the process of soil water loss , and record the indications of the two tensiometers corresponding to multiple preset times to realize the determination of the soil moisture characteristic curve of the soil dehumidification process; by setting the first vessel and setting the ring knife in the first vessel the clay plate, and the first vessel is configured such that when the moisture characteristic curve of the soil moisture absorption process is determined, the water in the first vessel and the upper end surface of the clay plate are always kept at the same height, so that after the ring knife is placed on the clay plate, The soil in the ring knife can absorb water continuously, and the measuring instrument measures and records the weight of the soil in the ring knife, the first vessel, the clay plate and the ring knife corresponding to the soil at multiple preset moments in the process of soil water absorption, and records multiple preset times. Set the indications of the two tensiometers corresponding to the time to realize the determination of the soil moisture characteristic curve of the soil moisture absorption process. According to the quantity recorded by the measuring instrument during the soil dehumidification process, the soil moisture characteristic curve of the soil dehumidification process can be obtained; according to the quantity recorded by the measuring instrument during the soil moisture absorption process, the soil moisture characteristic curve of the soil moisture absorption process can be obtained. Therefore, the device and method for determining the moisture characteristic curve of the soil dehumidification and moisture absorption process provided by the embodiments of the present invention can be used to determine the soil moisture characteristic curve of the soil moisture absorption process and the dehumidification process.

Description of drawings

In order to illustrate the technical solutions in the embodiments of the present invention more clearly, the following briefly introduces the accompanying drawings used in the description of the embodiments. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can also be obtained from these drawings without creative effort.

1 is a schematic structural diagram of a ring knife provided by an embodiment of the present invention;

2 is a schematic structural diagram of a first vessel and a second vessel according to an embodiment of the present invention;

FIG. 3 is a schematic structural diagram of a measuring instrument provided in an embodiment of the present invention.

The reference numbers in the figure are:

1. Ring knife;

2. Tensiometer;

3. Measuring instrument;

301. display screen;

302. button;

303, seat plate;

4. Clay board;

5. The first vessel;

501. bracket;

6. The second vessel;

7. Catheter;

8. Pipelines;

9. Switch.

Detailed ways

In order to make the technical solutions and advantages of the present invention clearer, the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

The embodiment of the present invention provides a device for measuring the moisture characteristic curve of soil dehumidification and moisture absorption process, including a ring knife 1, two tensiometers 2, a measuring instrument 3, a clay plate 4 and a first vessel 5, wherein,

The side wall of the ring knife 1 is provided with two openings (not shown with reference numerals in the figure, located at the tensiometer 2), and the two openings are located at different heights of the side wall of the ring knife 1. The ring knife 1 is configured to be nested outside the soil to be assayed;

two tensiometers 2 are configured to be respectively adapted to be inserted into the soil through the two openings and to measure the tension of the soil;

The clay plate 4 is placed in the first vessel 5 for supporting the ring knife 1;

The first vessel 5 is configured to keep the water in the first vessel 5 and the upper end surface of the clay plate 4 at the same height all the time when the moisture characteristic curve of the soil moisture absorption process is determined;

The measuring instrument 3 is configured to measure and record the weight of the ring knife 1 and the soil in the ring knife 1 corresponding to a plurality of preset times, or the weight of the ring knife 1 , the first vessel 5 , the clay plate 4 and the soil in the ring knife 1 . , and record the indications of the two tension meters 2 corresponding to multiple preset moments.

Wherein, the time interval between two adjacent preset moments may be equal. The time interval can be set by the operator, for example, can be set to 10 minutes, or 5 minutes.

The working principle of the device for measuring the moisture characteristic curve of the soil dehumidification and moisture absorption process provided by the embodiment of the present invention is described below:

When using the device provided in the embodiment of the present invention to measure the soil moisture characteristic curve of the soil dehumidification process, first put the ring knife 1 outside the soil to be tested that has been soaked in water, and place it on the measuring instrument 3, and then put the two The tensiometers 2 are respectively inserted into the soil in the ring knife 1 through the corresponding openings on the ring knife 1 . The soil continues to lose water, and the measuring instrument 3 measures and records the weight of the ring knife 1 and the soil corresponding to multiple preset times, and records the indications of the two tension meters 2 corresponding to multiple preset times. When the indications of the two tensiometers 2 no longer change, the dehumidification process of the soil ends, and the dehumidified soil is obtained.

When using the device provided in the embodiment of the present invention to measure the soil moisture characteristic curve of the soil moisture absorption process, the ring knife 1 and the dehumidified soil are placed on the clay plate 4 in the first vessel 5, and the first vessel 5 is placed on the clay plate 4. On the measuring instrument 3, the measuring instrument 3 measures and records the weights of the ring knife 1, the first vessel 5, the clay plate 4 and the soil corresponding to multiple preset times, and records the weights of the two tension meters 2 corresponding to the multiple preset times. number. Keep the water in the first vessel 5 at the same height as the top of the clay plate 4, so that the soil can absorb water all the time. When the readings of the two tensiometers 2 no longer change, the moisture absorption process of the soil ends.

According to the quantity recorded by the measuring instrument 3 during the soil dehumidification process, the soil moisture characteristic curve of the soil dehumidification process can be obtained; according to the quantity recorded by the measuring instrument 3 during the soil moisture absorption process, the soil moisture characteristic curve of the soil moisture absorption process can be obtained.

In the device for measuring the moisture characteristic curve of the soil dehumidification and moisture absorption process provided by the embodiment of the present invention, two openings are arranged on the ring knife 1, so that the two tensiometers 2 can be respectively inserted into the to-be-detected through the corresponding openings. The tension of the soil is measured in the soil; the ring knife 1 and the soil absorbing water are placed on the measuring instrument 3, so that the measuring instrument 3 measures and records the corresponding ring knife 1 and the ring knife 1 of the soil at multiple preset moments in the process of soil water loss The weight of the soil in the soil is recorded, and the indications of the two tensiometers 2 corresponding to multiple preset times are recorded, so as to realize the determination of the soil moisture characteristic curve of the soil dehumidification process; A clay plate 4 for placing the ring knife 1 is arranged in the 5, and the first vessel 5 is configured so that when the moisture characteristic curve of the soil moisture absorption process is determined, the water in the first vessel 5 and the upper end surface of the clay plate 4 are always kept at the same level. The same height, so that after the ring knife 1 is placed on the clay plate 4, the soil in the ring knife 1 can continue to absorb water, and the measuring instrument 3 measures and records multiple preset times during the soil water absorption process. The weight of the soil in the vessel 5, the clay plate 4 and the ring knife 1 is recorded, and the indications of the two tensiometers 2 corresponding to multiple preset times are recorded to realize the determination of the soil moisture characteristic curve of the soil moisture absorption process. According to the quantity recorded by the measuring instrument 3 during the soil dehumidification process, the soil moisture characteristic curve of the soil dehumidification process can be obtained; according to the quantity recorded by the measuring instrument 3 during the soil moisture absorption process, the soil moisture characteristic curve of the soil moisture absorption process can be obtained. Therefore, the device for determining the moisture characteristic curve of the soil dehumidification and moisture absorption process provided by the embodiment of the present invention can be used to determine the soil moisture characteristic curve of the soil moisture absorption process and the dehumidification process.

In this embodiment, as shown in FIG. 3 , the measuring instrument 3 is provided with a panel, and a display screen 301 is arranged on the panel, and the display screen 301 is used to display the data measured by the measuring instrument 3; The buttons 302 are respectively used to control the switch of the measuring instrument 3 and to set the preset time.

Wherein, as shown in FIG. 2 , the bottom surface of the first vessel 5 is provided with a bracket 501 , the clay plate 4 is placed on the bracket 501 , and the bracket 501 is an annular plate arranged on the inner wall of the first vessel 5 .

The first vessel 5 is configured so that when the moisture characteristic curve of the soil moisture absorption process is determined, the water in the first vessel 5 and the upper end surface of the clay plate 4 are always kept at the same height, which can be achieved in various ways, and the following one is now provided. Implementation:

As shown in FIG. 2 , the device also includes a sealed second vessel 6, the first vessel 5 is in communication with the second vessel 6, and the water in the second vessel 6 is suitable for flowing into the first vessel 5; A conduit 7 is provided, and one end of the conduit 7 extends to the outside of the second vessel 6; the upper end of the first vessel 5 is open, the conduit 7 and the first vessel 5 constitute a communication device, and the water in the conduit 7 and the upper end surface of the clay plate 4 are always kept at At the same height, the water between the water level line of the second vessel 6 and the bottom of the conduit 7 is used to supply the moisture absorption of the soil in the ring knife 1 .

In this way, the upper ends of the first vessel 5 and the conduit 7 are both communicated with the outside world, and the lower ends are communicated through the second vessel 6, and the two constitute a communication device. Make the water in the conduit 7 and the upper end surface of the clay plate 4 at the same height, when the soil absorbs the water in the first vessel 5, the water in the second vessel 6 enters the first vessel 5, so that the first vessel 5 The water is always kept at the same height as the upper end surface of the clay plate 4, so that the soil can always absorb water.

In order to make the water in the second vessel 6 flow into the first vessel 5, as shown in FIG. 2, a liquid outlet is opened on the side wall of the second vessel 6, and a liquid inlet is opened on the side wall of the first vessel 5, The liquid outlet is communicated with the liquid inlet through the pipeline 8 .

Specifically, the position of the liquid inlet is set below the upper end surface of the clay plate 4, so that when the liquid enters the first vessel 5, the water absorption process of the soil is not affected. In order to keep the water in the conduit 7 always at the same height as the upper end surface of the clay plate 4 , the height of the water in the second vessel 6 is set to be greater than the height of the clay plate 4 .

The first vessel 5 may be a watch glass, and the second vessel 6 may be a Martens bottle. The opening above the Martens bottle is sealed with a rubber stopper, and the rubber stopper is provided with an opening suitable for the conduit 7 to pass through. The sealing of the second vessel 6 means that all other places are sealed except for the liquid outlet and the opening through which the conduit 7 on the rubber plug passes.

In order to conveniently control the flow of liquid between the second vessel 6 and the first vessel 5 , as shown in FIG. 2 , a switch 9 is provided on the pipeline 8 .

In this way, before starting to measure the moisture characteristic curve of the soil moisture absorption process, the switch 9 is closed to prevent the water in the second vessel 6 from flowing into the first vessel 5 . When the measurement is started, the switch 9 is turned on, the second vessel 6 is communicated with the first vessel 5 , and the water in the second vessel 6 can flow into the first vessel 5 .

In order to facilitate the insertion of two tensiometers 2 into the ring knife 1 when the ring knife 1 is placed on the clay plate 4 in the first vessel 5 , the ring knife 1 is configured such that when placed on the clay plate 4 , the two The opening is located above the first vessel 5 .

In this way, when the ring knife 1 is placed on the clay plate 4, since the two openings are located above the first vessel 5, when the two tensiometers 2 are respectively inserted into the soil through the corresponding openings, the two tensiometers 2 are respectively is located above the first vessel 5 so that the first vessel 5 does not interfere with the insertion of the tensiometer 2 .

In order to facilitate the placement of the ring knife 1 , as shown in FIG. 3 , the measuring instrument 3 is provided with a seat plate 303 for placing the ring knife 1 .

Before the soil dehumidification process, the soil to be tested needs to be saturated with water. In order to facilitate the soil to be tested to be saturated with water, the device may further include a screen chassis for placing the ring knife 1 and the soil to be tested, and placed in water, so that the soil to be tested absorbs water.

Specifically, when the soil is saturated with water, first use the ring knife 1 to take the soil to be tested, then place the ring knife 1 on the screen chassis, and then place the screen chassis in water so that the height of the water is lower than the ring knife 1 the lower opening.

The embodiment of the present invention also provides a method for measuring the moisture characteristic curve of the soil dehumidification and moisture absorption process. The method is realized by using the above-mentioned device for measuring the moisture characteristic curve of the soil dehumidification and moisture absorption process. The method includes steps 201, 202, 203, 204 and 205. Each step will be described in detail below.

Step 201 , the ring knife 1 is set outside the water-saturated soil and placed on the measuring instrument 3 .

In this step, a screen pan can be used for water saturation of the soil. Specifically, when the soil is saturated with water, first use the ring knife 1 to take the soil to be tested, then place the ring knife 1 on the screen chassis, and then place the screen chassis in water so that the height of the water is lower than the ring knife 1 The lower opening of the ring knife 1 keeps the water level lower than the lower opening of the ring knife 1. Until water overflows from the upper end of the soil to be tested, it means that the water in the soil is saturated.

Step 202 , insert the two tensiometers 2 into the soil through the corresponding openings respectively.

Before this step, the two tensiometers 2 can be calibrated. The specific process is as follows:

After cleaning the tensiometer 2 with airless distilled water, immerse the detection end of the tensiometer 2 into a small beaker filled with airless distilled water, then remove the screw on the other end of the tensiometer 2, and connect it with a conduit of the buffer bottle. Connection, the other conduit of the buffer bottle is connected to the pressure gauge. The tensiometer 2 was repeatedly pressurized with a pressure gauge, so that the air bubbles in the upper part of the tensiometer 2 were completely discharged.

Pull out the tube of the buffer bottle from the screw hole on the upper part of the tensiometer 2, fill the tensiometer 2 with distilled water through the screw hole of the tensiometer 2, and then screw the screw into the screw hole.

Let the tensiometer 2 sit for a day or so. If there are air bubbles in the upper part of the tensiometer 2, repeat the above steps, and if there are no air bubbles, the following operations can be performed.

Connect the measuring instrument 3 and the tensiometer 2 with wires, and put the two tensiometers 2 into the calibrator device, one end of the calibrator is connected with the pressure gauge, and the measuring instrument 3 is connected with the computer. Open the ku-pf software on the computer desktop, select the calibration option in the work, input -50, click the Zero button, read the indications of the two tensiometers 2, and use the pressure gauge to pressurize until the calibration value of the calibrator is - - 0.5, the indications of the two tensiometers 2 are about -50. Click the refrence button to reduce the pressure of the pressure gauge to zero and remove the tension gauge 2.

Then, the two tensiometers 2 are respectively inserted into the soil in the ring knife 1 through the openings on the ring knife 1 .

Step 203: Use the measuring instrument 3 to measure and record the weight of the ring knife 1 and the soil corresponding to multiple preset times, and record the indications of the two tension meters 2 corresponding to the multiple preset times, until the two tension meters 2 The readings did not change, and dehumidified soil was obtained.

When the indications of the two tensiometers 2 no longer change, it means that the dehumidification process of the soil is completed.

Then, according to the data recorded by the measuring instrument 3, the soil moisture characteristic curve of the soil dehumidification process is obtained.

The soil moisture characteristic curve is the relationship between soil water suction and soil moisture content.

Among them, the calculation formula of soil moisture content at a certain time is:

W _i =W ₁ -W ₀ -W

In the formula,

θ——soil moisture content;

_Wi - the weight of water in the soil;

V is the volume of soil;

W ₁ - the total weight of the ring knife and soil

W ₀ - the weight of the ring knife;

W - weight of dry soil.

Among them, the total weight of the ring knife 1 and the dry soil and the weight of the dry soil need to be determined before the test.

The formula for calculating soil water suction is as follows:

In the formula,

S - soil water suction;

H _top - the indication of the tensiometer located at the top;

H _bottom - the reading of the tensiometer located at the bottom.

The soil moisture content and soil water suction corresponding to multiple times in the soil dehumidification process are calculated, and the relationship curve between soil water suction and soil moisture content can be obtained by fitting the square method, which is the soil moisture in the soil dehumidification process. characteristic curve.

Then, the soil moisture characteristic curve of the soil moisture absorption process is determined, and steps 204-205 are used.

Step 204 , place the ring knife 1 and the dehumidified soil on the clay plate 4 in the first vessel 5 , and keep the water in the first vessel 5 and the upper end surface of the clay plate 4 at the same height all the time.

Step 205: Use a measuring instrument to measure and record the weights of the ring knife and soil corresponding to multiple preset times, and record the indications of the two tensiometers corresponding to the multiple preset times, until the indications of the two tensiometers are no longer. Variety.

When the indications of the two tensiometers 2 are no longer changed, it indicates that the soil moisture absorption process is completed.

Then, according to the data recorded by the measuring instrument 3, the soil moisture characteristic curve of the soil moisture absorption process is obtained.

However, when measuring the data of the moisture absorption process of the soil, the water in the first container 5 is kept at the same height as the upper end surface of the clay plate 4 when the measurement is not started.

Among them, the calculation formula of soil moisture content at a certain time is:

W _i =W ₂ -W ₀ -W

In the formula,

θ——soil moisture content;

_Wi - the weight of water in the soil;

V is the volume of soil;

W ₂ - the total weight of the ring knife, the clay plate, the first utensil and the soil measured by the measuring instrument

W ₀ — measure the total weight of the front ring knife, the clay plate, the first vessel and the water in the first vessel;

W - weight of dry soil.

Among them, the total weight of the ring knife 1, the clay plate 4 and the first vessel 5 and the weight of the dry soil need to be determined before the test.

The formula for calculating soil water suction is as follows:

In the formula,

S - soil water suction;

H _top - the indication of the tensiometer located at the top;

H _bottom - the reading of the tensiometer located at the bottom.

The soil moisture content and soil water suction corresponding to multiple times in the soil moisture absorption process are calculated, and the relationship curve between soil water suction and soil moisture content can be obtained by fitting the square method, which is the soil moisture characteristic curve of the soil moisture absorption process. .

The method provided in the above embodiment and the embodiment of the device for determining the moisture characteristic curve of the soil dehumidification and moisture absorption process belong to the same concept.

The above description is only for the convenience of those skilled in the art to understand the technical solutions of the present invention, and is not intended to limit the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims (9)

1. a device for measuring the moisture characteristic curve of soil dehumidification and moisture absorption process, is characterized in that, comprises ring knife, two tensiometers, measuring instrument, clay plate and the first vessel, wherein, The side wall of the ring knife is provided with two openings, the two openings are located at different heights of the side wall, and the ring knife is configured to be sleeved outside the soil to be measured; the two tensiometers are configured to be respectively adapted to be inserted into the soil through the two openings and to measure the tension of the soil; the clay plate is placed in the first vessel for supporting the ring knife; The first vessel is configured such that when the moisture characteristic curve of the soil moisture absorption process is determined, the water in the first vessel and the upper end surface of the clay plate are always kept at the same height; A bracket is provided on the bottom surface of the first vessel, and the clay plate is placed on the bracket; The measuring instrument is configured to measure and record the weight of the ring knife and the soil in the ring knife, or the ring knife, the first vessel, the clay plate and the the weight of the soil in the ring knife, and record the indications of the two tensiometers corresponding to the plurality of preset moments; The measuring instrument is provided with a panel, a display screen is arranged on the panel, and the display screen is used to display the data measured by the measuring instrument; a plurality of buttons are also arranged on the panel, which are respectively used for controlling the switch of the measuring instrument and for setting preset time; The device further comprises a sealed second vessel, the first vessel is in communication with the second vessel, and the water in the second vessel is adapted to flow into the first vessel; A conduit is arranged in the second vessel, and one end of the conduit extends to the outside of the second vessel; The upper end of the first vessel is open, the conduit and the first vessel constitute a communication device, the water in the conduit and the upper end surface of the clay plate are always kept at the same height, and the water level of the second vessel is The water between the bottoms of the conduits is used to supply the soil moisture within the ring knife for moisture absorption. 2. The device for measuring the moisture characteristic curve of soil dehumidification and moisture absorption process according to claim 1, wherein the side wall of the second vessel is provided with a liquid outlet, and the side wall of the first vessel is provided with a liquid outlet. A liquid inlet is opened on the top, and the liquid outlet is communicated with the liquid inlet through a pipeline. 3 . The device for measuring the moisture characteristic curve of soil dehumidification and moisture absorption according to claim 2 , wherein a switch is provided on the pipeline. 4 . 4 . The device for determining the moisture characteristic curve of soil dehumidification and moisture absorption process according to claim 1 , wherein the ring knife is configured so that when placed on the clay plate, two of the opening holes are formed. 5 . above the first vessel. 5 . The device for measuring the moisture characteristic curve of soil dehumidification and moisture absorption process according to claim 1 , wherein the measuring instrument is provided with a seat plate for placing the ring knife. 6 . 6. The device for measuring the moisture characteristic curve of soil dehumidification and moisture absorption process according to any one of claims 1-5, wherein the device further comprises a screen chassis for placing the ring knife and all The soil to be tested is placed in water so that the soil to be tested absorbs water. 7. a method for measuring the moisture characteristic curve of soil dehumidification and moisture absorption process, it is characterized in that, described method adopts the device that measures the moisture characteristic curve of soil dehumidification and moisture absorption process described in any one of claim 1-6 To achieve, the method includes: The ring knife is set outside the saturated soil and placed on the measuring instrument; Insert the two tensiometers into the soil in the ring knife through the corresponding openings respectively; The measuring instrument is used to measure and record the weight of the ring knife and the soil in the ring knife corresponding to a plurality of preset moments, and record the indications of the two tension meters corresponding to the plurality of preset moments , until the indications of the two tensiometers no longer change, and the dehumidified soil is obtained; The ring knife and the dehumidified soil are placed on the clay plate in the first vessel, and the water in the first vessel and the upper end surface of the clay plate are always kept at the same height; The measuring instrument is used to measure and record the weight of the ring knife and the soil in the ring knife corresponding to a plurality of preset moments, and record the indications of the two tension meters corresponding to the plurality of preset moments , until the readings of the two tensiometers no longer change. 8. The method according to claim 7, wherein before inserting the two tensiometers into the soil in the ring knife through the corresponding openings, the method further comprises: The tensiometer is calibrated. 9. The method according to claim 8, characterized in that, before the ring knife is sleeved on the soil soaked in water and placed on the measuring instrument, the method further comprises: The ring knife is sleeved outside the soil to be tested and placed on the screen chassis, and then the screen chassis is placed in water, keeping the height of the water lower than the opening below the ring knife, Until the upper end of the soil to be tested overflows with water.

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