CN112858104A - Capillary tube water rise height measuring system and method - Google Patents
Capillary tube water rise height measuring system and method Download PDFInfo
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- CN112858104A CN112858104A CN202110100111.XA CN202110100111A CN112858104A CN 112858104 A CN112858104 A CN 112858104A CN 202110100111 A CN202110100111 A CN 202110100111A CN 112858104 A CN112858104 A CN 112858104A
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- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 title claims abstract description 164
- 238000000034 method Methods 0.000 title abstract description 32
- 239000002689 soil Substances 0.000 claims abstract description 99
- 238000005259 measurement Methods 0.000 claims abstract description 22
- 238000012360 testing method Methods 0.000 claims description 24
- 229910000734 martensite Inorganic materials 0.000 claims description 7
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- 238000001764 infiltration Methods 0.000 description 4
- 229920006395 saturated elastomer Polymers 0.000 description 4
- 238000003860 storage Methods 0.000 description 4
- 230000005484 gravity Effects 0.000 description 3
- 230000000670 limiting effect Effects 0.000 description 3
- 239000011148 porous material Substances 0.000 description 3
- 238000010276 construction Methods 0.000 description 2
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- 238000012986 modification Methods 0.000 description 2
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- 230000009467 reduction Effects 0.000 description 2
- 150000003839 salts Chemical class 0.000 description 2
- 238000005070 sampling Methods 0.000 description 2
- 239000008400 supply water Substances 0.000 description 2
- 238000012795 verification Methods 0.000 description 2
- 241000282342 Martes americana Species 0.000 description 1
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 description 1
- 238000012271 agricultural production Methods 0.000 description 1
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- 239000011521 glass Substances 0.000 description 1
- 238000007654 immersion Methods 0.000 description 1
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- 239000000463 material Substances 0.000 description 1
- 239000012466 permeate Substances 0.000 description 1
- 229920003023 plastic Polymers 0.000 description 1
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- 239000011780 sodium chloride Substances 0.000 description 1
- 238000010998 test method Methods 0.000 description 1
- 210000005239 tubule Anatomy 0.000 description 1
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N13/00—Investigating surface or boundary effects, e.g. wetting power; Investigating diffusion effects; Analysing materials by determining surface, boundary, or diffusion effects
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N15/00—Investigating characteristics of particles; Investigating permeability, pore-volume or surface-area of porous materials
- G01N15/08—Investigating permeability, pore-volume, or surface area of porous materials
- G01N15/0806—Details, e.g. sample holders, mounting samples for testing
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N15/00—Investigating characteristics of particles; Investigating permeability, pore-volume or surface-area of porous materials
- G01N15/08—Investigating permeability, pore-volume, or surface area of porous materials
- G01N15/082—Investigating permeability by forcing a fluid through a sample
- G01N15/0826—Investigating permeability by forcing a fluid through a sample and measuring fluid flow rate, i.e. permeation rate or pressure change
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N15/00—Investigating characteristics of particles; Investigating permeability, pore-volume or surface-area of porous materials
- G01N15/08—Investigating permeability, pore-volume, or surface area of porous materials
- G01N2015/0813—Measuring intrusion, e.g. of mercury
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Abstract
The embodiment of the application provides a capillary water rise height measurement system and method, and relates to the field of agricultural water conservancy projects, and the measurement system comprises: the Mariotte bottle is used for supplying water to the earth pillar according to a preset water head; the four-way pipe is located below the earth pillar, wherein: a first pipe orifice of the four-way pipe is communicated with a water permeable hole at the bottom of the earth pillar, a second pipe orifice is communicated with a water outlet valve on the Ma bottle through a water guide pipe, a third pipe orifice is communicated with the lower end of the pressure measuring pipe, and a fourth pipe orifice of the four-way pipe is connected with the differential pressure gauge through a hose; a first valve is arranged at the second pipe orifice, the upper end of the pressure measuring pipe is a free end and is communicated with the atmosphere, and the soil column and the pressure measuring pipe are arranged in the vertical direction and are parallel to each other; the water guide pipe is provided with a first valve, the water guide pipe between the first valve and the pipe orifice II is also connected with a water discharge pipe, and the water discharge pipe is provided with a second valve. Compared with the traditional measuring mode, the system has the advantages of high measuring precision by one order of magnitude, accuracy in measurement, automation, simplicity and easiness in operation and the like.
Description
Technical Field
The application relates to the field of agricultural water conservancy projects, in particular to a capillary water rise height measuring system and method.
Background
When the water content of the soil is gradually increased, the water which exceeds the maximum molecular water holding capacity is kept in capillary pores of the soil under the action of capillary force and is not controlled by gravity, and the water which is kept in the capillary pores of the soil by the capillary force is called capillary water.
The existence form and the rising height of capillary water in soil have profound influence on hydrology, geology, environment and agricultural hydraulic engineering construction. The overhigh underground water level can cause the disasters such as infiltration of the building foundation, reduction of strength, softening of soil, reduction of foundation bearing capacity, instability of soil slope and the like. Especially in agricultural production, capillary water affects the growth and yield of crops. The salt content of the soil bottom layer or underground water rises to the earth surface along with the capillary water, and after the water is evaporated, the salt content is accumulated in the surface soil to cause the salinization of the soil. The salinization of soil is mainly caused by that the underground water level is too high, the water rises to the ground surface along with capillary water, and when the time and the depth of accumulated water exceed the saline depth which can be tolerated by crops, the yield of the crops is reduced, and even the crops cannot be harvested. The control of the capillary water lifting height is a main measure for soil salinization improvement, and underground water needs to be controlled within a reasonable range in order to reduce the harm of soil salinization. For the problem of crop immersion, the critical burial depth of underground water is determined by adding a safe ultrahigh value to the capillary water rise height, so that a method for effectively measuring the capillary water rise height becomes a way for solving the problem of soil salinization.
Disclosure of Invention
The embodiment of the application provides a capillary water rise height measuring system and method, which can perform automatic continuous measurement on the basis of overcoming the technical problems and have the advantages of simple operation and high measuring precision (the precision is raised to 0.1 mm).
In order to solve the above problem, the embodiment of the application discloses a capillary water rise height measurement system, including:
the device comprises a March's flask, an earth pillar, a four-way pipe, a piezometer pipe and a differential pressure gauge;
the March bottle is used for supplying water to the earth pillar according to a preset water head;
the four-way pipe is located below the earth pillar, wherein:
a first pipe orifice of the four-way pipe is communicated with a water permeable hole at the bottom of the soil column;
a pipe orifice II of the four-way pipe is communicated with a water outlet valve on the Ma bottle through a water guide pipe;
a pipe orifice III of the four-way pipe is communicated with the lower end of the pressure measuring pipe, the upper end of the pressure measuring pipe is a free end and is communicated with the atmosphere, and the soil column and the pressure measuring pipe are arranged in the vertical direction and are parallel to each other;
a pipe orifice four of the four-way pipe is connected with the differential pressure gauge through a hose;
the water guide pipe is provided with a first valve, the water guide pipe between the first valve and the pipe orifice II is further connected with a drain pipe, and the drain pipe is provided with a second valve.
In an embodiment of the present application, the method further includes:
and the paperless recorder is connected with the differential pressure gauge and is used for recording data transmitted by the differential pressure gauge connected with the paperless recorder.
In an embodiment of the present application, the method further includes:
and the real-time data display is connected with the paperless recorder and is used for displaying the data transmitted by the paperless recorder.
In an embodiment of the present application, the method further includes:
the fixing piece is arranged between the earth pillar and the pressure measuring pipe and used for keeping the earth pillar and the pressure measuring pipe parallel.
In an embodiment of this application, still include earth pillar support, earth pillar support groove, wherein:
the earth pillar support groove is connected with the earth pillar support in a vertical direction in an adjustable mode, and the earth pillar support groove is used for placing the earth pillar.
In an embodiment of the present application, the soil column support groove includes a sleeve and a bearing plate connected to each other, and the soil column support includes a vertical rod; wherein:
the sleeve is sleeved on a vertical rod of the earth pillar support, a threaded hole is formed in the sleeve, and a brake bolt is arranged on the threaded hole;
the bearing flat plate is fixed with the outer side wall of the sleeve through a connecting piece, a semi-closed snap ring is arranged on the connecting piece, and the inner diameter of the snap ring is matched with the outer diameter of the earth pillar;
the plate surface of the bearing flat plate is used for placing the earth pillar.
In this application embodiment, still include mah-jong bottle support, mah-jong bottle draw-in groove, wherein:
the March's bottle clamping groove is connected with the March's bottle support in a vertically adjustable mode and used for placing the March's bottle.
In an embodiment of the present application, the mahalanobis bottle includes:
the Martensitic bottle comprises a Martensitic bottle body, a bottle opening and a bottle neck, wherein the Martensitic bottle body is provided with the bottle opening;
the elastic sealing plug is arranged in the bottle opening and has radial pressure on the bottle opening;
and the upper end of the air inlet thin tube is an air inlet, the lower end of the air inlet thin tube is an air outlet, the end face penetrating through the elastic sealing plug is arranged in the March's bottle body, and the air inlet is communicated with the inner cavity of the March's bottle body.
In an embodiment of the application, the pressure measuring pipe and the pipe wall of the soil column are provided with scale marks;
when the earth pillar is parallel to the pressure measuring pipe, the zero scale mark of the pressure measuring pipe is flush with the surface of a soil sample in the earth pillar.
In order to solve the above problem, an embodiment of the present application further discloses a capillary water rise height measurement method, where the method is applied to the system according to the embodiment of the present application, and the method includes:
loading a test soil sample into the soil column, and tamping in layers;
opening a water outlet valve and a first valve, keeping a second valve closed, enabling water in the March flask to enter the soil column and the pressure measuring pipe, closing the first valve when the water in the soil column rises to the surface of the test soil sample, and recording first data displayed by the differential pressure gauge at the moment;
opening a second valve, and recording second data displayed by the differential pressure gauge when the water level in the piezometric tube does not drop any more;
and calculating to obtain the water lifting height of the capillary tube in the soil column according to the actual thickness of the test soil in the soil column, the first data and the second data.
The embodiment of the application has the following advantages:
when capillary observation occurs in soil, the meniscus generates negative pressure to make the hydrostatic pressure in capillary smaller than atmospheric pressure, the difference is equal to the height of capillary water rising column of soil multiplied by the volume weight of water, and the negative pressure water column of capillary water rising height measured by the communicating pipe and the equal pressure surface of the height of capillary water falling column are utilized. Therefore, the Mariotte bottle is connected with the four-way pipe in the embodiment of the applicationThe soil capillary water elevation measuring device comprises a soil column, a pressure measuring pipe and a differential pressure gauge, wherein the soil column is arranged in the soil column, the pressure measuring pipe is communicated with the differential pressure gauge, the capillary water elevation in the soil column can be automatically measured, the differential pressure gauge can be used for respectively measuring the water column height of the pressure measuring pipe when soil in the soil column is saturated with water, free water in the soil column does not seep down after falling to a certain degree, namely the water column height when the liquid level in the pressure measuring pipe is stable, the difference between the two times of data before and after the differential pressure gauge is the water column height of the pressure measuring pipe. The measurement precision of the embodiment of the application can reach 0.1 millimeter water column (mmH)2O), compare the traditional approach and have an order of magnitude higher, and the sampling interval of differential pressure gauge can set up to 1s, can realize the continuous measurement to the data, very big manpower of having saved.
The embodiment of the application adopts the paperless recorder to connect the differential pressure gauge, adopts the real-time data display to connect the paperless recorder, can display the pressure change data in the pressure measuring tube on the real-time data display in real time, and is convenient for a tester to know the capillary water rise measurement data change situation at any time.
Drawings
In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.
FIG. 1 is a schematic structural diagram of a system for measuring the elevation of capillary water according to an embodiment of the present application;
FIG. 2 is a schematic view of the structure of the Mariotte bottle of one embodiment of the present application mounted on a support;
FIG. 3 is a schematic structural diagram of a four-way pipe according to an embodiment of the present application;
FIG. 4 is a schematic view of the structure of a soil column according to an embodiment of the present application;
FIG. 5 is a schematic diagram of the construction of a piezometer tube according to an embodiment of the present application;
FIG. 6(a) is a schematic plan view of the connection of a piezometer tube to an earth pillar according to an embodiment of the present application;
FIG. 6(b) is a schematic perspective view of the connection between a piezometer tube and an earth pillar according to an embodiment of the present application;
FIG. 7 is a schematic structural view of a differential pressure gauge according to an embodiment of the present application;
FIG. 8 is a schematic structural diagram of a paperless recorder according to an embodiment of the present application;
fig. 9 is a flowchart illustrating steps of a method for measuring a rise height of capillary water according to an embodiment of the present disclosure.
Description of reference numerals:
1-a mahalanobis bottle; 2-earth pillar; 3-four-way pipe; 4-piezometric tube; 5-differential pressure gauge; 6-water outlet valve; 7-a first valve; 8-a second valve; 9-paperless recorder; 10-real-time data display; 11-a fixing member; 12-a soil column support; 13-earth pillar support groove; 14-a snap ring; 15-a mahalanobis bottle holder; 16-a mahalanobis bottle neck; 17-a water storage barrel; 18-a drain pipe; 19-a water conduit; 20-a hose; 21-permeable pores.
Detailed Description
The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.
In the prior art, the indoor test method for measuring the capillary water rise mainly comprises a direct observation method and a Carminski capillary method. The direct observation method is intuitive, is suitable for various soils, but has long time consumption and high cost, and has different measurement results (small overlooking observation data and large upgoing observation data) due to different observation visual angles, so that errors are easy to exist. The traditional Casmins capillary method is simpler and more convenient than a direct observation method, has low cost, but cannot automatically measure, has poor precision, and has the precision of more than 5 mm.
To this end, referring to fig. 1, the present application embodiment newly proposes a capillary water elevation measurement system, which may include:
the device comprises a March's flask 1, a soil column 2, a four-way pipe 3, a piezometer pipe 4 and a differential pressure gauge 5;
the Mariotte bottle 1 is used for supplying water to the earth pillar 2 according to a preset water head;
the four-way pipe 3 is located below the soil column 2, wherein:
a first pipe orifice of the four-way pipe 3 is communicated with a water permeable hole 21 at the bottom of the soil column 2;
the second pipe orifice of the four-way pipe 3 is communicated with a water outlet valve 6 on the Ma bottle 1 through a water guide pipe 19;
a pipe orifice III of the four-way pipe 3 is communicated with the lower end of a pressure measuring pipe 4, the upper end of the pressure measuring pipe 4 is a free end and is communicated with the atmosphere, and the soil column 2 and the pressure measuring pipe 4 are arranged in the vertical direction and are parallel to each other;
a pipe orifice four of the four-way pipe 3 is connected with a differential pressure gauge 5 through a hose 20;
wherein, a first valve 7 is arranged on the water guide pipe 19, a water discharge pipe 18 is also connected on the water guide pipe 19 between the first valve 7 and the second pipe orifice, and a second valve 8 is arranged on the water discharge pipe 18.
In the embodiment of the application, the mahalanobis bottle 1 is a device which is based on the principle of a communicating vessel, so that the internal pressure and the external pressure of the container are consistent, and the constant water head and the automatic water replenishing in the mahalanobis bottle 1 are realized. Specifically, the mahalanobis bottle 1 may include: a March's bottle body (not marked in the figure) provided with a bottle mouth; an elastic sealing plug (not marked in the figure) which is arranged in the bottle mouth and has radial pressure on the bottle mouth; and the air inlet thin tube (not marked in the figure) is provided with an air inlet at the upper end, an air outlet at the lower end and penetrates through the end surface of the elastic sealing plug to be arranged in the March's bottle body, and the air inlet is communicated with the inner cavity of the March's bottle body. In this application embodiment, through pulling the tubule that admits air from top to bottom, can adjust the height of gas outlet, can realize the regulation of moisture infiltration flood peak through the position change of gas outlet height for mah-jong bottle 1 can supply water to earth pillar 2 according to predetermined flood peak, so that the user accomplishes capillary rising height measurement test on water under this flood peak. For how to adjust the water infiltration head between the marquise's bottle 1 and the earth pillar 2, reference can be made to the prior art, and details are not repeated here.
In the embodiment of the present application, further include mahalanobis bottle support 15, mahalanobis bottle draw-in groove 16, wherein: the mahalanobis bottle clamping groove 16 is connected with the mahalanobis bottle support 15 in an adjustable mode in the vertical direction, and the mahalanobis bottle clamping groove 16 is used for placing the mahalanobis bottle 1. Referring to fig. 1 and 2, the mahalanobis bottle clamping groove 16 is sleeved on a vertical rod of the mahalanobis bottle support 15 through a sleeve, a plurality of screw holes are formed in the wall of the vertical rod of the mahalanobis bottle support 15, the screw holes are arranged at certain intervals along the axial direction, the sleeve is connected with the vertical rod of the mahalanobis bottle support 15 through a brake bolt, namely, the brake bolt penetrates through the sleeve and is screwed into the screw hole to achieve the purpose of braking, the water head can be further adjusted through the measures, and the purpose of constant-pressure water supply is achieved.
The schematic structural diagram of the four-way pipe 3 can refer to fig. 3, that is, the first pipe orifice, the second pipe orifice and the fourth pipe orifice of the four-way pipe 3 are located on the same plane, and the third pipe orifice is perpendicular to and communicated with the first pipe orifice, the second pipe orifice and the fourth pipe orifice. It should be noted that, in the embodiment of the present application, the first nozzle, the second nozzle, the third nozzle, and the fourth nozzle are only used to distinguish the four nozzles of the four-way pipe 3, and do not have a limiting effect. The four-way pipe 3 can be made of transparent plastic pipe so as to observe the condition in the four-way pipe 3 and know whether the four-way pipe is blocked by soil or has air bubble section and the like.
Referring to fig. 4, the organic glass earth pillar 2 can be selected for the earth pillar 2, so that the phenomenon of capillary water rising in the earth pillar 2 can be observed conveniently. According to a preset test scheme, the bottom of the soil column 2 is provided with equal-size permeable stones, in order to prevent small-particle soil from blocking the permeable stones along with drainage, the permeable stones are covered with a piece of filter paper, and then test soil is filled in layers according to the requirements of the test scheme. The bottom of the earth pillar 2 is provided with a water permeable hole 21, the water permeable hole 21 is also called a water inlet/outlet hole, the water permeable hole 21 has water inlet and water outlet functions, when soil is to be saturated, the hole at the lower end of the earth pillar plays a role in water inlet, otherwise, the water outlet function is realized. Referring to fig. 1, the water permeable hole 21 is communicated with a first pipe orifice of the four-way pipe 3 through a water guide pipe 19, a second pipe orifice of the four-way pipe 3 is communicated with a water outlet valve 6 on the mahalanobis bottle 1 through the water guide pipe 19, wherein a first valve 7 is arranged on the water guide pipe 19, when the water outlet valve 6 and the first valve 7 are opened simultaneously, the communication between the mahalanobis bottle 1 and the earth pillar 2 can be realized, and the mahalanobis bottle 1 can supply water to the earth pillar 2 according to a water head determined by the current air outlet height. Under the water supply of the Ma's bottle 1, water in the earth pillar 2 permeates from bottom to top until the upper surface of the test soil in the earth pillar 2 is immersed, so that the test soil in the earth pillar 2 is in a saturated state. A drain pipe 18 is further connected to a water guide pipe 19 between the first valve 7 and the second pipe orifice, the drain pipe 18 is perpendicular to the part of the water guide pipe 19 which is horizontally arranged, a second valve 8 is arranged on the drain pipe 18, a drain hole is formed in the bottom end opening of the drain pipe 18, and free water in the soil column 2 is drained out of the drain hole under the action of gravity by opening the second valve 8. A water storage barrel 17 can be arranged below the drain pipe 18, and the water storage barrel 17 is used for containing water flowing out of the drain pipe 18.
In an embodiment of the present application, further include earth pillar support 12, earth pillar support groove 13, wherein: the earth pillar support groove 13 is connected with the earth pillar support 12 in a vertically adjustable manner, and the earth pillar support groove 13 is used for placing the earth pillar 2. Specifically, the earth pillar support groove 13 comprises a sleeve and a bearing flat plate which are connected with each other, and the earth pillar support 12 comprises a vertical rod; wherein: the sleeve is sleeved on a vertical rod of the earth pillar support 12, a threaded hole is formed in the sleeve, and a brake bolt is arranged on the threaded hole; one side end face of the bearing flat plate is fixed with the outer side wall of the sleeve through a connecting piece, a semi-closed snap ring 14 is arranged on the connecting piece, and the inner diameter of the snap ring 14 is matched with the outer diameter of the earth pillar 2; the surface of the bearing flat plate is used for placing the earth pillar 2. This application can support the montant of earth pillar support 12 through advancing the threaded hole on the sleeve with the brake bolt knob, reaches the braking purpose, and this will be favorable to adjusting 2 heights of earth pillar, satisfies the experiment demand. The structure of the bearing flat plate and the snap ring 14 can facilitate the placing and taking out of the earth pillar 2, and limit the earth pillar 2 on the bearing flat plate, so that the earth pillar is not easy to knock over.
When being connected four-way pipe 3 and pressure-measuring pipe 4, can upwards set up the three vertical settings of the mouth of pipe of four-way pipe 3 and direct lower extreme intercommunication with pressure-measuring pipe 4 to this intercommunication that has both realized earth pillar 2 and pressure-measuring pipe 4 also can reach earth pillar 2 and pressure-measuring pipe 4 and all set up and the purpose that is parallel to each other along vertical direction, and then can be through observing the water level variation in the pressure-measuring pipe 4, realize the measurement to capillary rising height on water in the experimental soil in the earth pillar 2.
In an embodiment of the present application, referring to fig. 4 and 5, respectively, scale marks are disposed on the pipe walls of the pressure measuring pipe 4 and the soil column 2; when earth pillar 2 and pressure-measuring pipe 4 are parallel, the zero scale mark of pressure-measuring pipe 4 is flushed with the surface of the soil sample in earth pillar 2. The zero scale mark of pressure-measuring pipe 4 is located the first half section of pressure-measuring pipe 4, flushes the zero scale mark of pressure-measuring pipe 4 and the surface of the interior soil sample of earth pillar 2, can make differential pressure gauge 5 survey data more accurate, reduces experimental measuring error.
Because pressure-measuring pipe 4 is longer, this application still is provided with mounting 11, mounting 11 sets up between earth pillar 2 and pressure-measuring pipe 4 for keep earth pillar 2 and pressure-measuring pipe 4 parallel. The fixing part 11 can be a support roll with sticky ends, a support roll with bayonets (one bayonet is large and the other bayonet is small), or a support roll with one end sleeved on the outer side of the piezometric tube 4 and the other end capable of supporting the outer wall of the earth pillar 2. The shape and structure of the fixing member 11 are not limited in the embodiment of the present application, and the object of the present invention can be achieved. Referring to fig. 6(a) and 6(b), a schematic plane structure and a schematic perspective structure of the connection of the piezometric tube 4 and the earth pillar 2 are respectively shown.
Referring to fig. 7, a schematic diagram of a differential pressure gauge 5 according to an embodiment of the present application is shown, wherein the differential pressure gauge 5 is used for measuring the pressure change in the piezometric tube 4. The differential pressure gauge 5 comprises an air inlet positive electrode interface, an air inlet negative electrode interface, a display panel, a function key panel, a power supply positive electrode and a power supply negative electrode and a USB signal output connector. When a test is carried out, the pipe orifice four of the four-way pipe 3 can be communicated with the positive port of the air inlet or the negative port of the air inlet of the differential pressure gauge 5 through the hose 20. When the hose 20 is connected with the positive port of the air inlet, the data measured by the differential pressure gauge 5 is a positive value; when the hose 20 is connected to the negative port of the air inlet, the data measured by the differential pressure gauge 5 is negative (the absolute value thereof is the actual value). Before the test, when two air inlets (positive and negative air inlets) of the differential pressure gauge 5 are communicated with the outside atmosphere, and the differential pressure of two interfaces of the differential pressure gauge 5 is not zero, a user can press a zero setting button on the front surface of the panel to correct zero setting. It should be noted that when the hose 20 sags and the earth pillar 2 or the pressure measuring tube 4 drains, liquid water may enter the hose 20, causing measurement errors, and therefore, in an embodiment of the present invention, the nozzle of the four-way tube 3 is filled with air-permeable and water-impermeable material or the hose 20 connecting the nozzle four and the differential pressure gauge 5 is ensured to be at the same level as the nozzle four.
To sum up, this application embodiment adopts four-way pipe 3 to link together Ma shi bottle 1, earth pillar 2, piezometer pipe 4 and differential pressure gauge 5, can realize the automatic measurement to capillary rising height on water in earth pillar 2, adopts differential pressure gauge 5 to measure the numerical value of piezometer pipe 4 after filling with water and reaching the stability very much, and its measurement accuracy can reach 0.1 millimeter water column (mmH)2O), compared with the traditional method, the method is higher by one order of magnitude, and the sampling interval of the differential pressure gauge 5 can be set to be 1s, so that the continuous measurement of data can be realized, and the manpower is greatly saved.
In an embodiment of the present application, referring to fig. 1 and 8, the capillary water elevation measuring system further comprises a paperless recorder 9 connected to the differential pressure gauge 5 for recording data transmitted by the differential pressure gauge 5 connected thereto. This application embodiment is through being connected paperless record appearance 9 and differential pressure gauge 5, can be after opening differential pressure gauge 5, and in passing through the data line with continuous measurement's data to paperless record appearance 9, paperless record appearance 9 can be with the visual and storage data of differential pressure gauge 5 survey air pressure. When the paperless recorder 9 is connected to the differential pressure gauge 5, a USB signal output connector of the differential pressure gauge 5 is connected to a USB port of the paperless recorder 9.
In an embodiment of the present application, referring to fig. 1, the capillary water elevation measurement system may further include: and the real-time data display 10 is connected with the paperless recorder 9 and is used for displaying the data transmitted by the paperless recorder 9. The real-time data display 10 may be a desktop computer, a notebook computer, or a stand-alone display. This application embodiment can pass through USB data line with paperless record appearance 9 and real-time data display 10 and be connected, can show the pressure change data in the piezometric tube 4 on real-time data display 10 in real time, and the experimenter of being convenient for knows capillary water rise height measurement data change situation at any time.
In conclusion, the system has the advantages of high measurement precision, strong automation, convenience in operation, labor saving and the like.
To address the technical problem of the present application, referring to fig. 9, a flowchart of steps of a method for measuring a capillary water rise height according to an embodiment of the present application is shown, where the method is applied to a system for measuring a capillary water rise height according to an embodiment of the present application, and the method may include the following steps:
step S1: filling a test soil sample into the soil column 2, and tamping in layers;
step S2: opening a water outlet valve 6 and a first valve 7, keeping a second valve 8 closed, enabling water in the Martensitic flask 1 to enter the earth pillar 2 and the piezometric tube 4, closing the first valve 7 when the water in the earth pillar 2 rises to the surface of the test soil sample, and recording first data P displayed by the differential pressure gauge 5 at the momentin；
Step S3: opening the second valve 8, when the water level in the piezometer tube 4 does not drop any more, recording the second data P displayed by the differential pressure gauge 5 at that timest；
Step S4: and calculating the water lifting height of the capillary tube in the soil column 2 according to the actual thickness of the soil tested in the soil column 2, the first data and the second data.
The working principle of the capillary water lifting height measuring system is as follows: when capillary observation occurs in soil, the meniscus generates negative pressure to make the hydrostatic pressure in capillary smaller than atmospheric pressure, the difference is equal to the height of water column of capillary rising of soil multiplied by the volume weight of water, and the negative pressure water column of capillary rising height measured by the communicating pipe and the equal pressure surface of the height of water column of piezometer tube 4. Therefore, in the application, the difference between the two previous and subsequent data of the differential pressure gauge 5 is the height of the water column descending by the piezometer tube 4, the actual thickness h of the test soil in the soil column 2 is subtracted from the difference, and the calculated capillary water lifting height in the soil column 2 is the capillary water lifting height of the test soil.
In the test process, firstly, step S1 is executed, in order to prevent soil particles in the soil column 2 from being discharged from the bottom of the soil column 2 when the test soil is drained, a layer of permeable stone should be added to the bottom of the soil column 2, a piece of filter paper is laid on the permeable stone, then the test soil sample is taken and loaded into the soil column 2 according to the requirements of the test scheme, and the soil is tamped in layers. In order to improve the test efficiency, the test piece can be soaked by water after being compacted in layers, and the water saturation state is not achieved at the moment. Then, the water conduit 19 and the hose 20 of the whole system are connected to ensure the tightness.
Next, step S2 is executed, the second valve 8 is closed, the water outlet valve 6 and the first valve 7 are opened, the water in the marten bottle 1 enters the earth pillar 2 and the pressure-measuring tube 4 through the water conduit, and simultaneously the differential pressure gauge 5 measures the water pressure of the pressure-measuring tube 4 in real time, that is, the water pressure from the hose interface of the differential pressure gauge 5 to the water surface of the pressure-measuring tube 4, when the soil water in the earth pillar 2 is saturated, that is, the water in the pressure-measuring tube 4 reaches the zero scale (the zero scale reference here is the soil surface, not the actual differential pressure count value, and the zero scale of the pressure-measuring tube 4 corresponds to the maximum value of the differential pressure gauge 5), the first valve 7 is closed, and the first data h displayed by the differential pressure gaugeinAt this time, the differential pressure gauge 5 has the maximum value.
Then, the second valve 8 is opened, free water in the earth pillar 2 begins to be discharged under the action of gravity, the liquid level of the pressure measuring pipe 4 also begins to fall, water in the earth pillar 2 does not seep after falling to a certain degree due to the capillary action of soil, the liquid level in the pressure measuring pipe 4 is stable at the moment, namely the water level does not fall, and second data h displayed by the differential pressure gauge 5 at the moment is recordedst。
Finally, according to the first data hinAnd second data hstThe calculated liquid level descending height of the piezometric tube 4 is delta h:
△h＝hin-hst (1)；
the measured soil capillary water rise height is as follows:
hm＝△h-h＝hin-hst-h (2)；
wherein h is the actual thickness of the soil tested in the soil column 2, the soil column 2 is given in advance, the height from the soil surface to the bottom surface in the soil column 2 is given, and h is unchanged in the process of infiltration and drainage.
In practice, even after the liquid level in the pressure-measuring pipe 4 is stabilized by visual observation immediately after the test is carried out, the pressure-measuring pipe 4 is lowered by a height H, and the soil capillary water rise height H is calculated from the visual observation resultn＝H-h。
Thus, the result h can be calculated by visual observationnTo the point of passing the present applicationMeasured hmAnd (6) carrying out verification. Verification proves that the measurement precision of the method is one order of magnitude higher than that of the traditional method, and the capillary rise height can be known accurately and intuitively.
It should be noted that, in the present specification, the embodiments are all described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments may be referred to each other.
It should also be noted that, in this document, the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience in describing the present application and simplifying the description, but do not indicate or imply that the referred device or element must have a specific orientation, be configured and operated in a specific orientation, and thus, should not be construed as limiting the present application. Moreover, relational terms such as "first" and "second" are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions or should not be construed as indicating or implying relative importance. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or terminal that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or terminal. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in the process, method, article, or terminal equipment comprising the element.
The technical solutions provided by the present application are described in detail above, and the principles and embodiments of the present application are described herein by using specific examples, which are only used to help understanding the present application, and the content of the present description should not be construed as limiting the present application. While various modifications of the illustrative embodiments and applications will be apparent to those skilled in the art based upon this disclosure, it is not necessary or necessary to exhaustively enumerate all embodiments, and all obvious variations and modifications can be resorted to, falling within the scope of the disclosure.
Claims (10)
1. A capillary water rise height measurement system, comprising:
the device comprises a March's flask (1), an earth pillar (2), a four-way pipe (3), a piezometer pipe (4) and a differential pressure gauge (5);
the March's bottle (1) is used for supplying water to the soil column (2) according to a preset water head;
the four-way pipe (3) is positioned below the earth pillar (2), wherein:
a first pipe orifice of the four-way pipe (3) is communicated with a water permeable hole (21) at the bottom of the soil column (2);
a pipe orifice II of the four-way pipe (3) is communicated with a water outlet valve (6) on the Mariotte bottle (1) through a water guide pipe (19);
a pipe orifice III of the four-way pipe (3) is communicated with the lower end of the pressure measuring pipe (4), the upper end of the pressure measuring pipe (4) is a free end and is communicated with the atmosphere, and the soil column (2) and the pressure measuring pipe (4) are arranged in the vertical direction and are parallel to each other;
a pipe orifice four of the four-way pipe (3) is connected with the differential pressure gauge (5) through a hose (20);
the water guide pipe (19) is provided with a first valve (7), the water guide pipe (19) between the first valve (7) and the pipe orifice II is further connected with a drain pipe (18), and the drain pipe (18) is provided with a second valve (8).
2. The system of claim 1, further comprising:
and the paperless recorder (9) is connected with the differential pressure gauge (5) and is used for recording data transmitted by the differential pressure gauge (5) connected with the paperless recorder.
3. The system of claim 2, further comprising:
and the real-time data display (10) is connected with the paperless recorder (9) and is used for displaying the data transmitted by the paperless recorder (9).
4. The system of claim 1, further comprising:
the fixing piece (11) is arranged between the earth pillar (2) and the pressure measuring pipe (4) and used for keeping the earth pillar (2) and the pressure measuring pipe (4) parallel.
5. The system according to claim 1, further comprising a column support (12), a column support trough (13), wherein:
the earth pillar support groove (13) is connected with the earth pillar support (12) in a vertical direction in an adjustable mode, and the earth pillar support groove (13) is used for placing the earth pillar (2).
6. System according to claim 5, characterized in that the column support trough (13) comprises interconnected sleeves, load-bearing plates, and the column support (12) comprises vertical bars; wherein:
the sleeve is sleeved on a vertical rod of the earth pillar support (12), a threaded hole is formed in the sleeve, and a brake bolt is arranged on the threaded hole;
the bearing flat plate is fixed with the outer side wall of the sleeve through a connecting piece, a semi-closed snap ring (14) is arranged on the connecting piece, and the inner diameter of the snap ring (14) is matched with the outer diameter of the earth pillar (2);
the surface of the bearing flat plate is used for placing the earth pillar (2).
7. The system of claim 1, further comprising a mahalanobis bottle holder (15), a mahalanobis bottle slot (16), wherein:
the Marble bottle clamping groove (16) is connected with the Marble bottle support (15) in a vertical direction in an adjustable mode, and the Marble bottle clamping groove (16) is used for placing the Marble bottle (1).
8. System according to claim 1 or 7, characterized in that said Marioter (1) comprises:
the Martensitic bottle comprises a Martensitic bottle body, a bottle opening and a bottle neck, wherein the Martensitic bottle body is provided with the bottle opening;
the elastic sealing plug is arranged in the bottle opening and has radial pressure on the bottle opening;
and the upper end of the air inlet thin tube is an air inlet, the lower end of the air inlet thin tube is an air outlet, the end face penetrating through the elastic sealing plug is arranged in the March's bottle body, and the air inlet is communicated with the inner cavity of the March's bottle body.
9. The system according to claim 1, characterized in that the piezometric tube (4) and the wall of the earth pillar (2) are provided with graduation marks;
when the earth pillar (2) is parallel to the pressure measuring pipe (4), the zero scale mark of the pressure measuring pipe (4) is flush with the surface of a soil sample in the earth pillar (2).
10. A capillary water rise height measurement method, applied to the system of any one of claims 1 to 9, comprising:
filling a test soil sample into the soil column (2), and tamping in layers;
opening a water outlet valve (6) and a first valve (7), keeping a second valve (8) closed, enabling water in the Martian bottle (1) to enter the soil column (2) and the pressure measuring pipe (4), closing the first valve (7) when the water in the soil column (2) rises to the surface of a test soil sample, and recording first data displayed by a differential pressure gauge (5) at the moment;
opening a second valve (8), and recording second data displayed by the differential pressure gauge (5) when the water level in the piezometer tube (4) does not drop any more;
and calculating the water lifting height of the capillary tube in the soil column (2) according to the actual thickness of the soil tested in the soil column (2), the first data and the second data.
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| CN115436235A (en) * | 2022-09-07 | 2022-12-06 | 成都理工大学 | Laboratory permeability coefficient determination method based on capillary water rise |
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| CN115436235A (en) * | 2022-09-07 | 2022-12-06 | 成都理工大学 | Laboratory permeability coefficient determination method based on capillary water rise |
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