KR20130017561A - Earth pressure detecting device based on optical fiber with temperature compensation sensor - Google Patents
Earth pressure detecting device based on optical fiber with temperature compensation sensor Download PDFInfo
- Publication number
- KR20130017561A KR20130017561A KR1020110080061A KR20110080061A KR20130017561A KR 20130017561 A KR20130017561 A KR 20130017561A KR 1020110080061 A KR1020110080061 A KR 1020110080061A KR 20110080061 A KR20110080061 A KR 20110080061A KR 20130017561 A KR20130017561 A KR 20130017561A
- Authority
- KR
- South Korea
- Prior art keywords
- optical fiber
- sensor
- earth pressure
- diaphragm
- present
- Prior art date
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- 239000013307 optical fiber Substances 0.000 title claims abstract description 81
- 239000012530 fluid Substances 0.000 claims abstract description 6
- 238000005259 measurement Methods 0.000 claims description 6
- 229920005989 resin Polymers 0.000 claims description 6
- 239000011347 resin Substances 0.000 claims description 6
- 239000011241 protective layer Substances 0.000 claims description 4
- 238000000034 method Methods 0.000 claims 7
- 102100024513 F-box only protein 6 Human genes 0.000 description 9
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- 102100022116 F-box only protein 2 Human genes 0.000 description 7
- 101000824158 Homo sapiens F-box only protein 2 Proteins 0.000 description 7
- 239000000835 fiber Substances 0.000 description 4
- 239000010720 hydraulic oil Substances 0.000 description 4
- 238000005192 partition Methods 0.000 description 4
- 230000035882 stress Effects 0.000 description 4
- 230000007423 decrease Effects 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 230000001681 protective effect Effects 0.000 description 2
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- 239000000853 adhesive Substances 0.000 description 1
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- 238000009530 blood pressure measurement Methods 0.000 description 1
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- 239000003822 epoxy resin Substances 0.000 description 1
- 230000006355 external stress Effects 0.000 description 1
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- 229910001220 stainless steel Inorganic materials 0.000 description 1
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- 238000003466 welding Methods 0.000 description 1
Images
Classifications
-
- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D31/00—Protective arrangements for foundations or foundation structures; Ground foundation measures for protecting the soil or the subsoil water, e.g. preventing or counteracting oil pollution
- E02D31/10—Protective arrangements for foundations or foundation structures; Ground foundation measures for protecting the soil or the subsoil water, e.g. preventing or counteracting oil pollution against soil pressure or hydraulic pressure
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L1/00—Measuring force or stress, in general
- G01L1/24—Measuring force or stress, in general by measuring variations of optical properties of material when it is stressed, e.g. by photoelastic stress analysis using infrared, visible light, ultraviolet
- G01L1/242—Measuring force or stress, in general by measuring variations of optical properties of material when it is stressed, e.g. by photoelastic stress analysis using infrared, visible light, ultraviolet the material being an optical fibre
-
- 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
- G01L11/02—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 by optical means
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L9/00—Measuring steady of quasi-steady pressure of fluid or fluent solid material by electric or magnetic pressure-sensitive elements; Transmitting or indicating the displacement of mechanical pressure-sensitive elements, used to measure the steady or quasi-steady pressure of a fluid or fluent solid material, by electric or magnetic means
- G01L9/0041—Transmitting or indicating the displacement of flexible diaphragms
- G01L9/0076—Transmitting or indicating the displacement of flexible diaphragms using photoelectric means
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2201/00—Features of devices classified in G01N21/00
- G01N2201/08—Optical fibres; light guides
- G01N2201/088—Using a sensor fibre
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- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Life Sciences & Earth Sciences (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Hydrology & Water Resources (AREA)
- Environmental & Geological Engineering (AREA)
- Mining & Mineral Resources (AREA)
- Paleontology (AREA)
- Civil Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Structural Engineering (AREA)
- Measuring Fluid Pressure (AREA)
Abstract
A torometer based on an optical fiber sensor for measuring earth pressure is disclosed. The present invention is a hydraulic tank for maintaining a predetermined fluid sealable; And a diaphragm for detecting a pressure applied to the fluid connected by the hydraulic tank and a flow path, coupled to the diaphragm, and connected in series with the first optical fiber sensor for measuring deformation of the diaphragm and the first optical fiber sensor. Provided is a tonometer including a second optical fiber sensor for temperature compensation, and a pressure sensor unit including a housing protecting the first and second optical fiber sensors. According to the present invention, it is possible to provide an optical fiber-based torometer capable of measuring a precise change in earth pressure by compensating for a sensor error caused by temperature change.
Description
The present invention relates to a tonometer, and more particularly, to a tonometer based on an optical fiber sensor for measuring the earth pressure.
In general, in civil engineering construction, the earth pressure gauge measures the change of the earth pressure due to the load of the surrounding ground to determine whether the earth structure is stable. For example, the earth pressure of the facility, the load of the ground or foundation building, or the earth pressure of the dam, etc. It is used to determine the stability of each structure by measuring.
Conventional earth pressure gauges can be largely divided into vibration-type earth pressure gauge and strain gauge type earth pressure gauge.
First, the vibration expression earth pressure gauge is composed of a filter, a diaphragm, a vibration string, an electromagnetic coil, and the like. When the earth pressure acts on the diaphragm, the diaphragm is deformed according to the pressure change, and thus the tensile force of the vibrating string is changed. When the tensile force is changed, the natural frequency is also changed, so the frequency of the AC voltage generated when the vibrating string is vibrated by the electromagnetic coil is read and converted into water pressure. However, the vibrating hydraulic pressure gauge has a problem that the initial measurement value is unstable zero drift or the hysteresis phenomenon due to the pressure increase and decrease, and the vibration string is easily damaged by the impact. In addition, in the case of a vibrating type tonometer, since the vibrating string itself, which is a sensor unit for detecting earth pressure, is made of a metal material, it may be corroded by reacting with moisture in the air.
On the other hand, a strain gauge type tonometer is composed of a strain gauge attached to a member on which the earth pressure acts to measure the micro displacement of the member according to the earth pressure. The strain gauge changes its resistance value as it deforms, and it can measure the load applied from the resistance value of the strain gauge. As described above, the strain gauge earth pressure gauge has the advantage that the load can be precisely measured by changing the deformation occurring in the object by the load as a corresponding electric signal, but there is a possibility of generating noise due to interference of the electric signal. It has the disadvantage that durability is not guaranteed in use.
In addition, these conventional torometers have a measurement error due to the deformation of the sensor material in accordance with the change in temperature, but at present there is no earth pressure gauge to compensate for such errors.
On the other hand, the optical fiber sensor is not only excellent in durability, but also widely used for the safety diagnosis of the structure because it is not affected by the number of measurement points and no noise effect of the signal, and is gradually replacing the conventional strain gauge based sensor.
Therefore, the earth pressure gauge using the optical fiber sensor will be able to exhibit high measurement accuracy and high durability which cannot be obtained with the conventional earth pressure gauge.
SUMMARY OF THE INVENTION The present invention aims at providing an optical fiber-based earth pressure gauge in view of the problems of the prior art and advantages of the optical fiber sensor.
An object of the present invention is to provide an optical fiber-based earth pressure gauge that can measure the precise change in the earth pressure by compensating for the sensor error due to temperature changes.
In order to achieve the above technical problem, the present invention, a hydraulic tank for maintaining a predetermined fluid sealable; And a diaphragm for detecting a pressure applied to the fluid connected by the hydraulic tank and a flow path, coupled to the diaphragm, and connected in series with the first optical fiber sensor for measuring deformation of the diaphragm and the first optical fiber sensor. Provided is a tonometer including a second optical fiber sensor for temperature compensation, and a pressure sensor unit including a housing protecting the first and second optical fiber sensors.
In the present invention, the earth pressure sensor is preferably provided with at least three optical fiber fixing member. At this time, one of the optical fiber fixing member is preferably a free end moving in accordance with the deformation of the diaphragm, and the remaining of the optical fiber fixing member is preferably a fixed end irrelevant to the deformation of the diaphragm.
In the present invention, the earth pressure sensor unit may further include a tension control mechanism for the initial tensile stress of the optical fiber sensor.
In the present invention, the optical fiber sensor is preferably an FBG sensor.
In addition, the earth pressure gauge of the present invention is characterized by compensating the measured value of the second optical fiber sensor from the stress measured value of the first optical fiber sensor.
In the present invention, the earth pressure sensor unit may further include a resin protective layer for protecting the sensor. In this case, it is preferable that the first and second optical fiber sensors are provided outside the resin protective layer.
According to the present invention, it is possible to provide an optical fiber-based torometer capable of measuring a precise change in earth pressure by compensating for a sensor error caused by temperature change.
In addition, the present invention can configure the earth pressure sensor and the temperature compensation sensor with a single optical fiber, it is possible to manufacture a durable earth pressure sensor with a simple structure.
1 is a schematic diagram illustrating the principle of operation of the earth pressure gauge according to the present invention.
2 is a perspective view specifically showing a tonometer according to a preferred embodiment of the present invention.
3 is a cross-sectional view showing an example of the earth pressure sensor unit according to a preferred embodiment of the present invention.
4 is an exploded perspective view of components inserted into the lower space of the housing of the earth pressure sensor of FIG.
BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail with reference to the preferred embodiments of the present invention with reference to the drawings.
Hereinafter, the principle of operation of the earth pressure gauge of the present invention will be described with reference to FIG. 1.
Referring to Figure 1, the earth pressure sensor of the present invention is preferably configured based on a fiber bragg grating (FBG) sensor (F). Specifically, the FBG sensor is composed of two sensors (FBG1, FBG2) arranged in series. As shown, the two sensors may be implemented with one extended optical fiber.
Each of the two FBG sensors FBG1 and FBG2 is maintained with a predetermined tension applied thereto. To this end, fixing members S1, S2 and S3 of at least three optical fiber sensors are provided. Each fixing member (S1, S2, S3) may be implemented by a predetermined member (232, 234, 250 of FIGS. 3 and 4) of the optical fiber fixture as will be described later.
In the present invention, one of the two FBG sensors FBG1 and FBG2 functions as a temperature compensation sensor, and the other function as a pressure sensor. For example, as shown, the FBG1 is a temperature compensation sensor and the FBG2 is a pressure sensor.
At this time, the fixing members (S1, S2) of the both ends of the FBG1 acts as a fixed end, one end of the fixing member (S3) of the FBG2 acts as a free end.
The distance L0 between the fixing members S1 and S2 as the fixing end does not change. However, the tension of FBG1 changes according to the temperature change of the surrounding environment in which the earth pressure gauge is buried. For example, at a temperature higher than the reference temperature, the tension is relaxed by the stretching of the optical fiber, and at a lower temperature, the tension is increased by the contraction of the optical fiber. As the tension increases and decreases, the spacing of the Bragg gratings engraved in the optical fiber sensor changes, and the change in temperature can be compensated for.
The fixing member S3 as the free end is movable back and forth. The diaphragm is connected to the fixing member S3. When an external force acts on the
When the movement of the fixing member S3 occurs due to the applied earth pressure, the length of the FBG2 is thereby changed, and as a result, the tension applied to the FBG2 sensor is changed. The change in tension of the FBG2 sensor changes the Bragg lattice spacing from which the stress acting on the FBG sensor can be calculated.
By offsetting the Bragg lattice change of the FBG1 sensor with the change in Bragg lattice spacing occurring in the FBG2 sensor, the external stress acting on the actual earth pressure gauge can be obtained.
As is well known, the degree of shrinkage of the optical fiber in the present invention can be preferably measured using a Fiber Bragg Grating (FBG) sensor. The FBG sensor is formed with a grating at predetermined intervals in the optical fiber, and measures the wavelength change of the reflected light that is incident upon the optical fiber. In this way, the pressure acting on the diaphragm can be calculated by measuring the amount of change in the Bragg lattice spacing. Thus, although not shown, the present invention may be equipped with a conventional FBG sensor metrology system that includes an LED or laser light source and a photodiode to calculate Bragg grating spacing.
2 is a perspective view specifically showing a tonometer according to a preferred embodiment of the present invention.
Referring to Figure 2, the
The
When pressure is applied to the
In the present invention, the
Additionally, the
The
In addition, in the present invention, the
As shown, the
3 is a cross-sectional view showing an example of the
Referring to FIG. 3, the earth
3 and 4, a member for installing the optical fiber sensor will be described in detail.
4 is an exploded perspective view of components inserted into the lower space of the
First, the first
The optical fiber extending from the first
A series of mounting
As shown, the
The
100
120
200
220
224
232, 234 Both ends of the first
242, 246, 248
250 Second
310 branch conduit
Claims (8)
Diaphragm for detecting the pressure applied to the fluid connected by the hydraulic tank and the flow path, the first optical fiber sensor coupled to the diaphragm and connected in series with the first optical fiber sensor for deformation measurement of the diaphragm A torometer comprising: a pressure sensor unit including a compensation second optical fiber sensor and a housing protecting the first and second optical fiber sensors.
The earth pressure sensor further comprises at least three optical fiber fixing members.
One of said optical fiber fixing members is a free end moving according to the deformation of said diaphragm.
A tonometer, characterized in that the remaining of the optical fiber fixing member is a fixed end irrelevant to the deformation of the diaphragm.
The earth pressure sensor further comprises a tension control mechanism for adding the initial tensile stress of the optical fiber sensor.
The tonometer, characterized in that the optical fiber sensor is an FBG sensor.
And the tonometer compensates the measured value of the second optical fiber sensor in the stress measured value of the first optical fiber sensor.
The earth pressure sensor further includes a resin protective layer for protecting the sensor,
And the first and second optical fiber sensors are installed outside the resin protective layer.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| KR1020110080061A KR20130017561A (en) | 2011-08-11 | 2011-08-11 | Earth pressure detecting device based on optical fiber with temperature compensation sensor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| KR1020110080061A KR20130017561A (en) | 2011-08-11 | 2011-08-11 | Earth pressure detecting device based on optical fiber with temperature compensation sensor |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| KR20130017561A true KR20130017561A (en) | 2013-02-20 |
Family
ID=47896706
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| KR1020110080061A KR20130017561A (en) | 2011-08-11 | 2011-08-11 | Earth pressure detecting device based on optical fiber with temperature compensation sensor |
Country Status (1)
| Country | Link |
|---|---|
| KR (1) | KR20130017561A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106595918A (en) * | 2016-11-17 | 2017-04-26 | 中国科学院武汉岩土力学研究所 | Long-term monitoring apparatus and method for soil pressure outside duct piece of shield tunnel |
| KR102073118B1 (en) * | 2018-08-29 | 2020-02-04 | 대한민국 | Measurement System of Debris Flow Sediment Discharge Using Load Cell |
| US10969283B2 (en) | 2017-06-16 | 2021-04-06 | Saint-Gobain Adfors Canada, Ltd. | Sensing textile |
-
2011
- 2011-08-11 KR KR1020110080061A patent/KR20130017561A/en not_active Application Discontinuation
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106595918A (en) * | 2016-11-17 | 2017-04-26 | 中国科学院武汉岩土力学研究所 | Long-term monitoring apparatus and method for soil pressure outside duct piece of shield tunnel |
| CN106595918B (en) * | 2016-11-17 | 2018-12-11 | 中国科学院武汉岩土力学研究所 | A kind of long term monitoring device and method of the outer soil pressure of duct pieces of shield tunnel |
| US10969283B2 (en) | 2017-06-16 | 2021-04-06 | Saint-Gobain Adfors Canada, Ltd. | Sensing textile |
| US11422046B2 (en) | 2017-06-16 | 2022-08-23 | Saint-Gobain Adfors Canada, Ltd. | Sensing textile |
| KR102073118B1 (en) * | 2018-08-29 | 2020-02-04 | 대한민국 | Measurement System of Debris Flow Sediment Discharge Using Load Cell |
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