CN114544363A - Pore water pressure measuring device suitable for frozen soil - Google Patents
Pore water pressure measuring device suitable for frozen soil Download PDFInfo
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- CN114544363A CN114544363A CN202210093731.XA CN202210093731A CN114544363A CN 114544363 A CN114544363 A CN 114544363A CN 202210093731 A CN202210093731 A CN 202210093731A CN 114544363 A CN114544363 A CN 114544363A
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- water pressure
- measuring device
- pore water
- pressure sensor
- frozen soil
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- 239000002689 soil Substances 0.000 title claims abstract description 52
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 title claims abstract description 41
- 239000011148 porous material Substances 0.000 title claims abstract description 39
- 230000035515 penetration Effects 0.000 claims abstract description 16
- 238000007789 sealing Methods 0.000 claims description 16
- 238000005192 partition Methods 0.000 claims description 11
- 238000012360 testing method Methods 0.000 abstract description 8
- 239000007788 liquid Substances 0.000 description 6
- 229920001971 elastomer Polymers 0.000 description 4
- 230000005540 biological transmission Effects 0.000 description 3
- 238000001125 extrusion Methods 0.000 description 3
- 238000005259 measurement Methods 0.000 description 3
- 238000000034 method Methods 0.000 description 3
- 239000012466 permeate Substances 0.000 description 3
- 238000004026 adhesive bonding Methods 0.000 description 2
- 238000009530 blood pressure measurement Methods 0.000 description 2
- 230000007797 corrosion Effects 0.000 description 2
- 238000005260 corrosion Methods 0.000 description 2
- DIOQZVSQGTUSAI-UHFFFAOYSA-N decane Chemical compound CCCCCCCCCC DIOQZVSQGTUSAI-UHFFFAOYSA-N 0.000 description 2
- 238000000605 extraction Methods 0.000 description 2
- 239000005457 ice water Substances 0.000 description 2
- 230000008595 infiltration Effects 0.000 description 2
- 238000001764 infiltration Methods 0.000 description 2
- 238000009434 installation Methods 0.000 description 2
- 239000010410 layer Substances 0.000 description 2
- 230000007774 longterm Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 239000002245 particle Substances 0.000 description 2
- 239000011241 protective layer Substances 0.000 description 2
- 229920006395 saturated elastomer Polymers 0.000 description 2
- 238000012546 transfer Methods 0.000 description 2
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 description 1
- 229910000831 Steel Inorganic materials 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000007872 degassing Methods 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 125000000118 dimethyl group Chemical group [H]C([H])([H])* 0.000 description 1
- 239000000835 fiber Substances 0.000 description 1
- 230000008014 freezing Effects 0.000 description 1
- 238000007710 freezing Methods 0.000 description 1
- 230000001788 irregular Effects 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000000691 measurement method Methods 0.000 description 1
- 230000002035 prolonged effect Effects 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 239000011435 rock Substances 0.000 description 1
- 229920002545 silicone oil Polymers 0.000 description 1
- 239000011780 sodium chloride Substances 0.000 description 1
- 239000010959 steel Substances 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
- G01N3/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N3/08—Investigating strength properties of solid materials by application of mechanical stress by applying steady tensile or compressive forces
- G01N3/10—Investigating strength properties of solid materials by application of mechanical stress by applying steady tensile or compressive forces generated by pneumatic or hydraulic pressure
- G01N3/12—Pressure testing
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L11/00—Measuring steady or quasi-steady pressure of a fluid or a fluent solid material by means not provided for in group G01L7/00 or G01L9/00
-
- 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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- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Chemical & Material Sciences (AREA)
- Analytical Chemistry (AREA)
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Biochemistry (AREA)
- General Health & Medical Sciences (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Dispersion Chemistry (AREA)
- Fluid Mechanics (AREA)
- Force Measurement Appropriate To Specific Purposes (AREA)
- Investigating Strength Of Materials By Application Of Mechanical Stress (AREA)
- Measuring Fluid Pressure (AREA)
Abstract
The invention discloses a pore water pressure measuring device suitable for frozen soil, which comprises an outer shell, wherein a penetration plate is arranged at the upper end of the outer shell; and a pressure sensor is arranged in the outer shell and is positioned below the penetration plate. The pore water pressure measuring device suitable for the frozen soil solves the problems that when the micro pore water pressure sensor is used for testing the water pressure of the pore of the frozen soil, the pressure sensor is easy to deform and elements are damaged due to the huge frost heaving force when the soil body is frozen.
Description
Technical Field
The invention belongs to the technical field of rock-soil pore pressure measurement, and particularly relates to a pore water pressure measuring device suitable for frozen soil.
Background
The change of pore water pressure in the saturated soil body is very critical to the stress state of the soil body, and has important significance for researching the deformation and the strength of the soil body, so the measurement of the pore water pressure is indispensable in the soil mechanics research.
The frozen soil is used as rock soil material in a negative temperature state, most of water is frozen into ice, but still considerable water is not frozen and is distributed around soil particles in a liquid state, particularly in a temperature range of severe ice-water phase change, so that considerable pore water pressure can still be generated when the frozen soil is compressed. However, the conventional measurement method is difficult to work due to the special process of ice-water phase change. The applicant carries out long-term pore water pressure measurement and exploration in a laboratory aiming at small-size frozen soil samples, and finds that although the existing micro pore water pressure sensor can sense the pore pressure, the huge frost heaving force of the frozen soil body can easily cause deformation of the sensor and damage of elements, the economic cost is extremely high, and the output result is disordered and irregular.
Disclosure of Invention
The invention aims to provide a pore water pressure measuring device suitable for frozen soil, which solves the problems that when a micro pore water pressure sensor is used for testing the water pressure of a pore of the frozen soil, the pressure sensor is easy to deform and elements are damaged due to the huge frost heaving force when a soil body is frozen.
In order to achieve the purpose, the technical scheme adopted by the invention is as follows: a pore water pressure measuring device suitable for frozen soil comprises an outer shell, wherein a penetration plate is arranged at the upper end of the outer shell; and a pressure sensor is arranged in the outer shell and is positioned below the penetration plate.
As a preferable technical solution of the present invention, the present invention further includes a fixing ring, the permeate plate is disposed in the fixing ring, and the fixing ring is disposed at an upper end of the outer casing.
As a preferable aspect of the present invention, the fixing ring is screw-fitted to an upper end of the outer case.
As a preferred technical scheme of the present invention, an inner partition plate is disposed in the outer casing, a through hole is disposed in the middle of the inner partition plate, and the inner partition plate is located between the permeation plate and the pressure sensor.
As a preferable aspect of the present invention, a plurality of seal rings are provided between the pressure sensor and the inner wall of the outer housing.
In a preferred embodiment of the present invention, a sealing cap is provided at a lower end of the outer housing, and a lower end of the pressure sensor extends from the sealing can.
As a preferable aspect of the present invention, the sealing cap is screw-fitted to a lower end of the outer case.
As a preferable aspect of the present invention, a pair of shallow grooves is provided on an outer edge of an upper surface of the fixing ring.
The invention has the beneficial effects that: (1) the pore water pressure measuring device for the frozen soil has the advantages that the used micro pressure sensor is generally thin in the shell wall, the deformation of the shell wall is easy to cause the damage of internal elements in a frozen soil test, the device applies a shell body outside the micro pressure sensor as a protective layer, and the shell body bears all frost heaving force and cannot be transferred to an expensive micro pressure sensor, so that the service life of the micro pressure sensor is greatly prolonged, and the frozen soil test cost is saved. (2) The pore water pressure measuring device suitable for frozen soil can still keep smaller size, can meet the strict size requirement of an indoor test on a sample built-in sensor, and reduces the influence on the soil structure. (3) According to the pore water pressure measuring device suitable for frozen soil, the design built in the device can realize flexible assembly, damaged parts are convenient to replace, and meanwhile, the existence of the outer shell body greatly avoids the corrosion of soil bodies to the micro pressure sensor in long-term tests, especially in the soil bodies with corrosivity such as saline soil.
Drawings
The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the invention and not to limit the invention. In the drawings:
fig. 1 is a schematic structural diagram of a pore water pressure measuring device suitable for frozen soil according to the present invention.
In the figure: 1. the sealing structure comprises a fixing ring, 2 parts of a shallow groove, 3 parts of a penetration plate, 4 parts of an outer shell, 5 parts of a sealing ring, 6 parts of a pressure sensor, 7 parts of an upper internal thread, 8 parts of an internal partition plate, 9 parts of a lower internal thread and 10 parts of a sealing cover.
Detailed Description
Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the accompanying drawings are illustrative only for the purpose of explaining the present invention, and are not to be construed as limiting the present invention.
In the description of the present invention, if there are first and second described only for the purpose of distinguishing technical features, it is not understood that relative importance is indicated or implied or that the number of indicated technical features or the precedence of the indicated technical features is implicitly indicated or implied.
In the description of the present invention, unless otherwise explicitly limited, terms such as arrangement, installation, connection and the like should be understood in a broad sense, and those skilled in the art can reasonably determine the specific meanings of the above terms in the present invention in combination with the specific contents of the technical solutions.
As shown in fig. 1, the pore water pressure measuring device suitable for frozen soil of the present invention comprises an outer shell 4, wherein a permeable plate 3 is arranged at the upper end of the outer shell 4; a pressure sensor 6 is arranged in the outer shell 4, and the pressure sensor 6 is positioned below the infiltration plate 3. The permeate sheet 3 is arranged in a fixed ring 1, the fixed ring 1 being screw-fitted to the upper end of the outer casing 4.
The penetration plate 3 is arranged in the fixing ring 1 and then is connected in a penetration plate mounting cavity of the outer shell 4 through an upper internal thread 7, the miniature pressure sensor 6 is arranged in a sensor mounting cavity of the outer shell 4, and liquid pressure transfer media are filled in pores between the penetration plate 3 and each cavity. The pressure transmission medium can be a liquid medium which is not frozen at low temperature and is not dissolved in water, such as high-viscosity dimethyl silicone oil, decane and the like, the liquid medium can still transmit liquid pressure under a negative temperature environment due to the low-temperature non-freezing characteristic, a frozen soil structure is not damaged during measurement due to the water-insoluble characteristic, and an unsaturated state is not formed due to the fact that the liquid medium cannot migrate to other places from the penetration plate 3 when a soil sample is fully pumped with water or has a temperature gradient due to the high-viscosity characteristic.
In the technical scheme, the outer shell 4 plays a role of a protective layer, when the soil body is frozen, the pore pressure measuring device is extruded, the outer shell 4 completely bears extrusion force, and the extrusion force is buffered by a gap between the outer shell and the miniature pressure sensor 6, so that the sensor body cannot be damaged by internal elements due to extrusion; in addition, the sensor can be isolated from the soil body, so that the corrosion of the soil body to the sensor body during long-time measurement is prevented.
The pressure sensor is a miniature pressure sensor selected from a steel string type pressure sensor, a piezoresistive pressure sensor, a fiber grating type pressure sensor, a resistance strain gauge type pressure sensor, a differential resistance type pressure sensor, a capacitance type pressure sensor or a differential capacitance type pressure sensor.
After passing through the water seepage plate 3, water between the pores of the frozen soil is contacted with the pressure sensor 6, and the pressure sensor 6 detects the water pressure.
As shown in fig. 1, in the pore water pressure measuring device suitable for frozen soil of the present invention, an inner partition plate 8 is disposed in an outer casing 4, a through hole is disposed in the middle of the inner partition plate 8, and the inner partition plate 8 is located between a permeable plate 3 and a pressure sensor 6.
The inner partition plate 8 is used for limiting and supporting and limiting the fixing ring 1, and the pressure sensor 6 is prevented from being damaged due to too close contact.
As shown in fig. 1, in the pore water pressure measuring device applied to frozen earth of the present invention, a plurality of seal rings 5 are provided between a pressure sensor 6 and the inner wall of an outer casing 4.
A plurality of layers of O-shaped sealing rings 5 are arranged in a gap between the inner wall of the outer shell 4 and the miniature pressure sensor 6, so that the pressure sensor 6 can be firmly fixed in the outer shell 4, and pressure transfer media in a gap of a measuring end of the pressure sensor 6 can be prevented from leaking along a gap of a sensor mounting cavity to obtain an authentic measuring result
As shown in fig. 1, in a pore water pressure measuring device for frozen earth of the present invention, a lower end of an outer case 4 is screw-fitted with a sealing cap 10, and a lower end of a pressure sensor 6 is protruded from the sealing cap 10.
The fastening bolt 10 is connected to the lower part of the outer shell 4 through the lower thread 9 and tightly presses the O-shaped sealing ring 5, so that the installation is convenient.
As shown in fig. 1, in the pore water pressure measuring apparatus applied to frozen earth according to the present invention, a pair of shallow grooves 2 are provided at the outer edge of the upper surface of a stationary ring 1. The removal and mounting of the permeate sheet 3 is facilitated by means of corresponding tools. The penetration plate 3 can also be fixed to the outer shell 4 by other fixing means, such as gluing, snapping, etc.
The invention also provides a using method of the frozen soil pore water pressure measuring device, which comprises the following specific steps:
step 1, installing the polished penetration plate 3 on the penetration plate fixing ring 1, and if necessary, carrying out gluing treatment, and ensuring that two ends of the penetration plate 3 are flush with two ends of the fixing ring 1. Both are then screwed into the outer housing 4 along the upper internal thread 7.
And 2, sleeving a plurality of layers of O-shaped sealing rings 5 on the outer side of the miniature pressure sensor 6, placing the miniature pressure sensor into a sensor mounting cavity of the outer shell 4, and screwing a fastening bolt 10 along the thread 9 to tightly press the O-shaped sealing rings 5 so as to fix the miniature pressure sensor 6.
And 3, sleeving a rubber tube on the outer side of the outer shell 4 and enabling the rubber tube to be higher than the section of the outer shell 4 by a certain height to form a cavity with a certain volume.
And 4, facing the end face of the device upwards, injecting a certain amount of high-viscosity pressure transmission medium into the cavity of the rubber tube, then placing the rubber tube into an air extraction saturation container, performing degassing saturation by using a vacuum pump, observing that air extraction is stopped after bubbles do not emerge from the permeation plate 3, and standing for a period of time to ensure that the gap at the measuring end is completely filled and saturated by the high-viscosity pressure transmission medium.
And 5, inserting the measuring device into the soil body in the test process, and fully contacting the soil body. The test can be carried out by connecting the sensor to a measuring device.
And 6, the sensor can be repeatedly used, soil particles on the surface of the infiltration plate need to be cleaned before each use, and air is pumped again to saturate.
While the foregoing description shows and describes several preferred embodiments of the invention, it is to be understood, as noted above, that the invention is not limited to the forms disclosed herein, but is not to be construed as excluding other embodiments and is capable of use in various other combinations, modifications, and environments and is capable of changes within the scope of the inventive concept as expressed herein, commensurate with the above teachings, or the skill or knowledge of the relevant art. And that modifications and variations may be effected by those skilled in the art without departing from the spirit and scope of the invention as defined by the appended claims.
Claims (8)
1. The pore water pressure measuring device suitable for frozen soil is characterized by comprising an outer shell (4), wherein a penetration plate (3) is arranged at the upper end of the outer shell (4); a pressure sensor (6) is arranged in the outer shell (4), and the pressure sensor (6) is located below the penetration plate (3).
2. The pore water pressure measuring device suitable for frozen soil according to claim 1, further comprising a fixing ring (1), wherein the penetration plate (3) is disposed in the fixing ring (1), and the fixing ring (1) is disposed at an upper end of the outer casing (4).
3. The pore water pressure measuring device for frozen soil according to claim 2, wherein the fixing ring (1) is screw-fitted on the upper end of the outer shell (4).
4. The pore water pressure measuring device suitable for frozen soil according to claim 3, wherein an inner partition plate (8) is arranged in the outer shell (4), a through hole is arranged in the middle of the inner partition plate (8), and the inner partition plate (8) is positioned between the permeation plate (3) and the pressure sensor (6).
5. The pore water pressure measuring device suitable for frozen soil according to claim 4, wherein a plurality of sealing rings (5) are arranged between the pressure sensor (6) and the inner wall of the outer shell (4).
6. The pore water pressure measuring device for frozen soil according to claim 5, wherein the lower end of the outer casing (4) is provided with a sealing cover (10), and the lower end of the pressure sensor (6) protrudes from the sealing cover (10).
7. The pore water pressure measuring device for frozen soil according to claim 6, wherein the sealing cover (10) is screw-fitted at the lower end of the outer casing (4).
8. The pore water pressure measuring device suitable for frozen soil according to claim 7, wherein a pair of shallow grooves (2) are provided at the outer edge of the upper surface of the fixing ring (1).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210093731.XA CN114544363A (en) | 2022-01-26 | 2022-01-26 | Pore water pressure measuring device suitable for frozen soil |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210093731.XA CN114544363A (en) | 2022-01-26 | 2022-01-26 | Pore water pressure measuring device suitable for frozen soil |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN114544363A true CN114544363A (en) | 2022-05-27 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202210093731.XA Pending CN114544363A (en) | 2022-01-26 | 2022-01-26 | Pore water pressure measuring device suitable for frozen soil |
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| Country | Link |
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| CN (1) | CN114544363A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117054315A (en) * | 2023-10-13 | 2023-11-14 | 东北林业大学 | Frozen soil permeability coefficient measurement system |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102879148A (en) * | 2012-10-10 | 2013-01-16 | 基康仪器(北京)有限公司 | Device and method for measuring frozen soil pore water pressure |
| CN205426681U (en) * | 2016-03-16 | 2016-08-03 | 山东科技大学 | Multi -functional hydrate characteristic testing experiment device |
| CN110118628A (en) * | 2019-05-28 | 2019-08-13 | 中国科学院寒区旱区环境与工程研究所 | Frozen soil pore water pressure measurement device |
| CN113739984A (en) * | 2021-08-18 | 2021-12-03 | 中国科学院西北生态环境资源研究院 | Device for measuring frozen soil pore water pressure change |
-
2022
- 2022-01-26 CN CN202210093731.XA patent/CN114544363A/en active Pending
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102879148A (en) * | 2012-10-10 | 2013-01-16 | 基康仪器(北京)有限公司 | Device and method for measuring frozen soil pore water pressure |
| CN205426681U (en) * | 2016-03-16 | 2016-08-03 | 山东科技大学 | Multi -functional hydrate characteristic testing experiment device |
| CN110118628A (en) * | 2019-05-28 | 2019-08-13 | 中国科学院寒区旱区环境与工程研究所 | Frozen soil pore water pressure measurement device |
| CN113739984A (en) * | 2021-08-18 | 2021-12-03 | 中国科学院西北生态环境资源研究院 | Device for measuring frozen soil pore water pressure change |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117054315A (en) * | 2023-10-13 | 2023-11-14 | 东北林业大学 | Frozen soil permeability coefficient measurement system |
| CN117054315B (en) * | 2023-10-13 | 2024-01-09 | 东北林业大学 | Frozen soil permeability coefficient measurement system |
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