CN208297333U - A kind of quasi-distributed system and sensing device measuring soil moisture content - Google Patents
A kind of quasi-distributed system and sensing device measuring soil moisture content Download PDFInfo
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- CN208297333U CN208297333U CN201820405181.XU CN201820405181U CN208297333U CN 208297333 U CN208297333 U CN 208297333U CN 201820405181 U CN201820405181 U CN 201820405181U CN 208297333 U CN208297333 U CN 208297333U
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- fiber grating
- moisture content
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- hydrophilic rubber
- soil moisture
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Abstract
The utility model discloses a kind of quasi-distributed systems and sensing device for measuring soil moisture content, wherein measuring the quasi-distributed system of soil moisture content, including sensing device, fiber grating demodulation equipment and computer；Sensing device includes fiber grating and hydrophilic rubber, and fiber grating and hydrophilic rubber are tightly packaged together；Fiber grating in sensing device leads to fiber grating demodulation equipment by optical fiber；Fiber grating demodulation equipment is connect with computer.The quasi-distributed system and method for the utility model can be connected multiple moisture content sensing devices using FBG multiplexing technology on an optical fiber, sensing device is embedded in the soil body, it realizes quasi-distributed, the real-time monitoring to certain area and depth bounds soil moisture content, provides the distribution characteristics of moisture content and its effective information of variation for the engineering properties study of all kinds of soil bodys and application.Sensing device obtains the moisture content of the soil body in situ by measuring optical-fiber deformation, reduces measurement error caused by sampling, transport.
Description
Technical field
The utility model belongs to soil body engineering properties the field of test technology, the standard point of specifically a kind of measurement soil moisture content
Cloth system and sensing device.
Background technique
Soil moisture content has important influence to characteristics such as soil strength, deformation and infiltrations, and soil moisture content has
There is very strong Spatial-Temporal Variability, is one of the main indicator in soil body engineering properties study.Currently, measurement soil moisture content is common
Method have oven drying method, electric-resistivity method, time domain reflectometry, Ground Penetrating Radar method, frequency domain bounce technique, infrared sensing method, remote sensing image method
With spectra methods etc..The above method is commonly available to laboratory test, such as oven drying method, point measurement such as electric-resistivity method, Time Domain Reflectometry
Method, Ground Penetrating Radar method, frequency domain bounce technique；General estimation is made to a regional soil body surface water status again or only, it is difficult to
Precise measurement is carried out to the moisture content of deep soil, such as infrared sensing method, remote sensing image method and spectra methods.Therefore, it researches and develops
A kind of (standard) is distributed, the soil moisture content measurement method high to soil body deep, cost performance easy to install seems most important, for
Agricultural production and engineering construction are all of great significance.
Hydrophilic rubber is a kind of new function macromolecule material with water swelling, dehydration shrinkage and dual sealing characteristic
Material, is widely used as sealing material, sealing material and filler of civil construction etc..The high resiliency of hydrophilic rubber and preferable machinery are strong
Degree, so that volume may expand several times to hundred times to hydrophilic rubber after absorbing water.
Fiber bragg grating (FBG) is a kind of quasi-distributed optical fiber sensor, after it is stretched or compresses,
The central wavelength of FBG will drift about, and drawing, the compressive strain of the drift value and optical fiber of wavelength are in a linear relationship.FBG Fibre Optical Sensor
Technology has the advantages such as electromagnetism interference, corrosion-resistant, small in size, light-weight, essential safety, can realize quasi- point using multiplexing technology
Cloth test, is easily formed quasi-distributed measuring system.
Utility model content
The technical problem to be solved by the present invention is to provide a kind of quasi-distributed systems and biography for measuring soil moisture content
Induction device, the quasi-distributed system and measurement method can carry out quasi- distribution to certain area and depth bounds soil moisture content
Formula, real-time monitoring, for the engineering properties study of all kinds of soil bodys and using the effective of the distribution characteristics and its variation for providing moisture content
Information.The sensing device by measure optical-fiber deformation obtain the moisture content of the soil body in situ, test method is simple, reduce sampling,
Measurement error caused by transport solves the problems, such as original position, real-time and accurate measurement soil moisture content.
For achieving the above object, the utility model uses following technical scheme:
A kind of quasi-distributed system measuring soil moisture content, including sensing device (the hydrophilic rubber packaging structure of FBG-),
Fiber grating demodulation equipment and computer；Sensing device includes fiber grating and hydrophilic rubber, and fiber grating and hydrophilic rubber are tight
Sealing is fitted together；Fiber grating in sensing device extends to fiber grating demodulation equipment；Fiber grating demodulation equipment and meter
The connection of calculation machine.
By experimental calibration obtain sensor fiber grating central wavelength and soil moisture content relationship when, using experiment
Calibration system, experimental calibration system include insulating box, surface plate and weighing device, and surface plate and weighing device are placed in insulating box
In.
Further, fiber grating is located in hydrophilic rubber or fiber grating is wound in hydrophilic rubber surface.
Further, hydrophilic rubber is in a strip shape, and fiber grating is placed among two blocks of hydrophilic rubber of strip, close by gluing
It is packaged together；It is wrapped up around hydrophilic rubber using rigid porous materials, constrains the lateral displacement of hydrophilic rubber, aperture is advantageous
In the exchange of moisture of hydrophilic rubber and external environment.
Another kind improves, and sensing device further includes cylindrical model, and hydrophilic rubber is tightly fixed to cylindrical model side,
Fiber grating is wrapped on hydrophilic rubber.Cylinder is rigid material, swollen around centered on cylinder after hydrophilic rubber water absorbent
It is swollen.
Further, sensing device includes temperature sensor, and temperature sensor is for compensated optical fiber grating since temperature becomes
Central wavelength drift value caused by changing.
A kind of sensing device measuring soil moisture content, including fiber grating and hydrophilic rubber, fiber grating and hydrophilic rubber
Glue is tightly packaged together.
Further, the fiber grating is located in hydrophilic rubber or fiber grating is wound in hydrophilic rubber surface.
Further, the hydrophilic rubber is in a strip shape, and fiber grating is placed among two blocks of hydrophilic rubber of strip, passes through gluing
It is tightly packaged together；It is fixed around hydrophilic rubber using rigid porous materials, aperture is to be conducive to hydrophilic rubber and the external world
The exchange of moisture of environment.Make hydrophilic rubber can only be towards the extended direction dilation of optical fiber.
Another kind improves, and the sensing device of the measurement soil moisture content further includes cylindrical model, and hydrophilic rubber is close
It is fixed on cylindrical model side, fiber grating is wrapped on hydrophilic rubber.Hydrophilic rubber is expanded around centered on cylinder.
The quasi-distributed system and sensing device of a kind of measurement soil moisture content of the utility model, technical principle are as follows: base
Fiber-draw and compressive deformation caused by the hydrophilic rubber gluing encapsulating structure of FBG-, hydrophilic rubber water absorbent expansion, dehydration shrinkage,
The moisture content of the soil body is obtained by measuring center wavelength using calibration curve.It is implanted into when by the hydrophilic rubber gluing encapsulating structure of FBG-
In the soil body, exchange of moisture can occur for the soil body and expanded rubber until balancing, and rubber deformation caused by exchange of moisture can cause optical fiber
Deformation.It is demodulated to obtain corresponding central wavelength using (FBG) demodulator equipment, it is aqueous according to the central wavelength of calibration and the soil body
Rate formula, obtains out soil moisture content.
The quasi-distributed system and sensing device of a kind of measurement soil moisture content of the utility model are passed based on FBG optical fiber
Sense technology is by hydrophilic rubber together with optical fiber Bragg grating encapsulation, and using FBG optical fiber sensing technology, precise measurement is due to hydrophilic rubber
Fiber-draw caused by water swelling, dehydration shrinkage and compressive deformation can when rubber reaches dynamic equilibrium with soil moisture content
To obtain the moisture content of the soil body in situ by measuring optical-fiber deformation, test method is simple, reduces measurement caused by sampling, transport
Error solves the problems, such as original position, real-time and accurate measurement soil moisture content.In addition, can be in a light using FBG multiplexing technology
It connects on fibre multiple moisture content sensing devices, sensing device is embedded in the soil body by excavating groove or drilling in earth's surface,
It realizes quasi-distributed, the real-time monitoring to certain area and depth bounds soil moisture content, is ground for the engineering properties of all kinds of soil bodys
Study carefully and using the distribution characteristics of offer moisture content and its effective information of variation.
Detailed description of the invention
Fig. 1 is the utility model sensing device basic structure schematic diagram；
Fig. 2 is the structural schematic diagram of the utility model sensing device one embodiment；
Fig. 3 is column model schematic in another embodiment of the utility model sensing device；
Fig. 4 is the structural schematic diagram of another embodiment of the utility model the utility model sensing device；
Fig. 5 is the quasi-distributed system diagram of the utility model measurement soil moisture content；
Fig. 6 is indoor standardization test measurement plant system drawing.
Specific embodiment
With reference to the accompanying drawing, to the utility model proposes a kind of measurement soil moisture content quasi-distributed system and sensing
Device is described in detail.In the description of the present invention, it should be understood that term " left side ", " right side ", " top ",
The orientation or positional relationship of the instructions such as " lower part ", " bottom " is to be based on the orientation or positional relationship shown in the drawings, merely to just
In description the utility model and simplify description, rather than the device or element of indication or suggestion meaning there must be specific side
Position is constructed and operated in a specific orientation, and " first ", " second " etc. are not offered as the significance level of components, therefore cannot manage
Solution is limitations of the present invention.The specific size used in the present embodiment technical solution solely for the purpose of illustration, not
Limit the protection scope of the utility model.
As shown in figure 5, a kind of quasi-distributed system for measuring soil moisture content, including (the hydrophilic rubber of FBG- of sensing device 1
Glue encapsulating structure), fiber grating demodulation equipment 3 and computer 2.Sensing device 1 includes fiber grating 13 and hydrophilic rubber 12, light
Fine grating 13 and hydrophilic rubber 12 are tightly packaged together.Fiber grating 13 in sensing device 1 leads to optical fiber light by optical fiber
Grid demodulated equipment 3；Fiber grating demodulation equipment 3 is connect with computer 2.Sensing device 1 contains temperature sensor in including, and is used for
Compensated optical fiber grating central wavelength drift value due to caused by temperature change
As shown in fig. 6, using a calibration system, calibration system includes insulating box 4, surface for indoor standardization test
Ware 6 and weighing device 5.Surface plate 6 and weighing device 5 are placed in insulating box 4.Weighing device 5 selects balance in the present embodiment.
As shown in Figures 1 to 4, the first sensing device, hydrophilic rubber 12 is in a strip shape, but is not limited to bar shaped, also can be processed into
The other shapes such as cylinder, circular ring shape.Fiber grating 13 is placed in the centre of the hydrophilic rubber 12 of two pieces of strips, it is tight by gluing
Sealing is fitted together.The surrounding rigid porous materials 11 of hydrophilic rubber 12 are fixed, and aperture is to be conducive to hydrophilic rubber and outer
The exchange of moisture of boundary's environment.Make hydrophilic rubber can only be towards the extended direction dilation of optical fiber.In this implementation, hydrophilic rubber is added
Work is in strip, long 2.5cm, wide 0.5cm, thick 0.25cm, cubical expansivity 250%.It is hydrophilic that fiber grating is placed in two panels
The centre of rubber makes the hydrophilic rubber of two panels be fixed together with fiber grating by gluing encapsulation.It is required that optical fiber is close with rubber
Gluing, selected optical fiber type are SMF-28, and cladding diameter is 125.0 ± 0.7 μm, and coating diameter is 245 ± 5 μm, and inequality is even
Continuous point loss Wei≤0.35dB/km@1310nm He≤0.21dB/km@1550nm.
The second way is the cylindrical model 4 of a center hollow out, and hydrophilic rubber 12 is tightly fixed on model 4,
13 gluing of fiber grating is wrapped on the hydrophilic rubber 12.Hydrophilic rubber is expanded around centered on cylinder.
The first strip-shaped rubber-optical fibre raster package structure advantage is small in size, and encapsulating structure is simple.The disadvantage is that
One encapsulating structure can only be coupled with a grating.The advantage of second of cylindrical rubber optical fiber encapsulating structure be can with it is more
A grating coupling, sensitivity is stronger, and disadvantage is encapsulating structure complexity.
The requires of the utility model optical fiber and the close gluing of rubber, i.e., hydrophilic rubber water absorbent expansion, dehydration shrinkage will lead to
Fiber-draw and compressive deformation.By taking strip rubber as an example, fiber grating is placed in the centre of two strip rubber, passes through gluing
Strip-shaped rubber and fiber grating are fixed together by packaging method, form the hydrophilic rubber packaging structure of FBG-.Two strip rubber
Specification and size should be consistent, fiber grating is located at the centre of two strip-shaped rubbers, and with the close gluing of rubber.When hydrophilic rubber
When water swelling, dehydration shrinkage, stretching and the compressive deformation of fiber grating will lead to.
A method of using above-mentioned quasi-distributed systematic survey soil moisture content, comprising the following steps:
The first above-mentioned sensing device is subjected to Laboratory Calibration, i.e., the hydrophilic rubber packaging structure of FBG- is put into difference and contained
In the soil body of water rate, the central wavelength of FBG is obtained using fiber grating demodulation equipment, it is aqueous with the soil body to obtain FBG central wavelength
The relation curve of rate, specifically, comprising the following steps:
1) sensing device is placed in the clay sample that moisture content in surface plate is 70%, sealing place a period of time until
The exchange of moisture of hydrophilic rubber and clay reaches balance, and FBG central wavelength no longer changes；
2) surface plate is placed on the weighing device in 40 DEG C of insulating box, sample soil is made to dry dehydration；
3) central wavelength of 0.5h fiber grating demodulation device measuring fiber grating in dehydration process, while root are spaced
It is said that the reading of balance obtains the evaporation capacity of clay sample moisture, and then the moisture content of clay sample is calculated, obtained calibration is bent
Line is in piecewise linear relationship, and linear relationship is good:
Y=0.19x+1540 x >=50% (1)
Y=0.08x+1540 x≤50% (2)
In formula, x indicates that soil moisture content, y indicate central wavelength.
After the completion of Laboratory Calibration,
4) each sensing device is implanted into the soil body to be measured by being connected in series, by the quasi-distributed sense light of soil moisture content
Cable is connect with fiber grating demodulation equipment, and fiber grating demodulation equipment is connect with computer, and benefit is computerizedd control fiber grating
Demodulated equipment carries out data sampling and data analysis, forms the quasi-distributed measuring system of soil moisture content；Utilize drilling or groove
The quasi-distributed sensing device of soil moisture content is implanted in the soil body, is backfilled by the soil body in situ, soil moisture content standard is distributed
Formula sensing device is contacted with the soil body in situ, and the abundant exchange of moisture may be implemented.
5) measure the central wavelength of fiber grating in each sensing device, the soil moisture content according to obtained in step 3) with
The relationship of the central wavelength of fiber grating calculates the moisture content of the soil body to be measured.
Based on the description to the preferred embodiments of the present invention, it should be apparent that be defined by the appended claims
The utility model be not limited only to the specific detail illustrated in specification above, without departing from the utility model aims or
Range equally possible reaches the purpose of this utility model to many obviously change of the utility model.
Claims (9)
1. a kind of for measuring the quasi-distributed system of soil moisture content, which is characterized in that including sensing device, fiber grating solution
Adjust equipment and computer；Sensing device includes fiber grating and hydrophilic rubber, and fiber grating and hydrophilic rubber compact package are one
It rises；Fiber grating in sensing device leads to fiber grating demodulation equipment by optical fiber；Fiber grating demodulation equipment and computer
Connection.
2. the quasi-distributed system of measurement soil moisture content according to claim 1, which is characterized in that the fiber grating
In hydrophilic rubber or fiber grating is wound in hydrophilic rubber surface.
3. the quasi-distributed system of measurement soil moisture content according to claim 1, which is characterized in that the hydrophilic rubber
In a strip shape, fiber grating is placed among two blocks of hydrophilic rubber of strip, is tightly packaged together by gluing；It is adopted around hydrophilic rubber
It is wrapped up with rigid porous materials.
4. the quasi-distributed system of measurement soil moisture content according to claim 2, which is characterized in that the sensing device
It further include cylindrical model, hydrophilic rubber is tightly fixed to cylindrical model side, and fiber grating is wrapped on hydrophilic rubber.
5. the quasi-distributed system of measurement soil moisture content according to claim 1, which is characterized in that the sensing device
Including temperature sensor, it to be used for compensated optical fiber grating central wavelength drift value due to caused by temperature change.
6. a kind of for measuring the sensing device of soil moisture content, which is characterized in that including fiber grating and hydrophilic rubber, optical fiber
Grating and hydrophilic rubber are tightly packaged together.
7. according to claim 6 for measuring the sensing device of soil moisture content, which is characterized in that the fiber grating
In hydrophilic rubber or fiber grating is wound in hydrophilic rubber surface.
8. according to claim 7 for measuring the sensing device of soil moisture content, which is characterized in that the hydrophilic rubber
In a strip shape, fiber grating is placed among two blocks of hydrophilic rubber of strip, is tightly packaged together by gluing；It is adopted around hydrophilic rubber
It is fixed with rigid porous materials.
9. according to claim 7 for measuring the sensing device of soil moisture content, which is characterized in that further include cylindric mould
Type, hydrophilic rubber are tightly fixed to cylindrical model side, and fiber grating is wrapped on hydrophilic rubber.
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108279211A (en) * | 2018-03-25 | 2018-07-13 | 南京大学 | A kind of quasi-distributed system, sensing device and method measuring soil moisture content |
| CN109682853A (en) * | 2019-01-09 | 2019-04-26 | 南京大学 | A kind of frozen soil ice content distribution in-situ measuring method and device based on FBG |
| CN111248061A (en) * | 2020-02-24 | 2020-06-09 | 中国水利水电科学研究院 | Circulation-adjustable crop water irrigation system and method |
-
2018
- 2018-03-25 CN CN201820405181.XU patent/CN208297333U/en active Active
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108279211A (en) * | 2018-03-25 | 2018-07-13 | 南京大学 | A kind of quasi-distributed system, sensing device and method measuring soil moisture content |
| CN109682853A (en) * | 2019-01-09 | 2019-04-26 | 南京大学 | A kind of frozen soil ice content distribution in-situ measuring method and device based on FBG |
| CN109682853B (en) * | 2019-01-09 | 2024-02-13 | 南京大学 | FBG-based frozen soil ice content distributed in-situ measurement method and device |
| CN111248061A (en) * | 2020-02-24 | 2020-06-09 | 中国水利水电科学研究院 | Circulation-adjustable crop water irrigation system and method |
| CN111248061B (en) * | 2020-02-24 | 2021-11-02 | 中国水利水电科学研究院 | Circulation-adjustable crop water irrigation system and method |
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