CN211013323U - Optical fiber type rock stress sensor - Google Patents
Optical fiber type rock stress sensor Download PDFInfo
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- CN211013323U CN211013323U CN202020007279.7U CN202020007279U CN211013323U CN 211013323 U CN211013323 U CN 211013323U CN 202020007279 U CN202020007279 U CN 202020007279U CN 211013323 U CN211013323 U CN 211013323U
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Abstract
The utility model discloses an optical fiber type rock stress sensor, which comprises an armored optical cable, a rock cylinder, a bare fiber and an optical fiber sensing demodulator, wherein the bare fiber is arranged inside the rock cylinder; the rock column body is a columnar rock body taken from a rock area to be detected, and an axial blind hole is formed in the center of the end part of the rock column body; the bare optical fiber is arranged in the blind hole and is encapsulated and cured by epoxy resin; and the fiber core of the bare fiber is also provided with a fiber grating. The utility model adopts the rock medium to be tested as the sensor shell material, so that the matching error between the sensor and the rock can be effectively reduced, and the testing precision is improved; the fiber bragg grating is used as a core sensitive element, so that the sensor has the excellent characteristics of electromagnetic interference resistance, corrosion resistance and water resistance.
Description
Technical Field
The utility model belongs to the technical field of the sensing, especially, relate to an optic fibre formula rock stress sensor.
Background
The measurement of soil pressure in geotechnical media is an important content of research of soil mechanics theory and geotechnical engineering test, and the solution of a large number of geotechnical engineering theory and practical problems usually mainly depends on the direct measurement result of field prototype or model test, especially many research subjects in recent years relate to dynamic pressure test on the surface of a structure in rock or embedded in rock under the action of explosive impact load. The pressure measurement in the rock-soil medium is different from the pressure measurement in general fluid media such as liquid, air and the like, when the pressure measurement in the rock-soil medium is carried out, the sensor is embedded in the medium, and because the physical and mechanical properties of the sensor and the surrounding medium are different, the original stress field of the medium is changed, the stress concentration and redistribution phenomena are caused, so that the actual pressure measured by the sensor is different from the original real pressure, and the error generated by the phenomenon is generally called matching error. The existing research at home and abroad shows that the ratio of the height to the diameter (H/D) of the sensor (the ratio of the thickness H of the sensor to the diameter D of the sensor) to the modulus (E) of the sensorg/Es(Equivalence elastic modulus E of the sensorgElastic modulus E of rock-soil mediumsRatio) are two core factors that affect the match error. When E isg/EsIf the matching error is 0, the soil pressure sensor and the test medium are completely matched, and the test value is equal to the real stress, which is the most ideal case, but because the soil is of various types and the modulus of even one soil changes during the loading process, it is basically impossible to maintain the complete matching of the modulus of the soil pressure sensor and the modulus of the test medium.
SUMMERY OF THE UTILITY MODEL
The utility model aims at providing an optic fibre formula rock stress sensor has advantages such as matching error is little, the measuring accuracy is high, sound construction, environmental suitability is strong.
In order to realize the novel purpose of the above use, the utility model discloses take following technical scheme:
an optical fiber type rock stress sensor comprises an armored optical cable, a rock cylinder, a bare optical fiber and an optical fiber sensing demodulator, wherein the bare optical fiber is arranged inside the rock cylinder; the rock column body is a columnar rock body taken from a rock area to be detected, and an axial blind hole is formed in the center of the end part of the rock column body; the bare optical fiber is arranged in the blind hole and is encapsulated and cured by epoxy resin; and the fiber core of the bare fiber is also provided with a fiber grating.
The fiber bragg grating is a Fiber Bragg Grating (FBG) manufactured on a bare fiber.
The end face of the tail end of the rock cylinder is a pressure-sensitive face.
The fiber grating is parallel to the axial position of the rock cylinder.
Through the utility model discloses an implement, reached good result of use: an optical fiber type rock stress sensor adopts a rock medium to be tested as a sensor shell material, so that the matching error of the sensor and rock can be effectively reduced, and the test precision is improved; the fiber bragg grating is used as a core sensitive element, so that the sensor has the excellent characteristics of electromagnetic interference resistance, corrosion resistance and water resistance; the combined packaging structure of the rock shell, the epoxy resin and the armored optical cable enables the optical fiber sensor to be very firm, the survival rate and the durability of sensor installation are greatly improved, and extensive construction on a test site is not afraid.
Drawings
Fig. 1 is a schematic structural diagram of the present invention.
In the figure: 1. the device comprises an armored optical cable, 2, a rock cylinder, 3, epoxy resin, 4, a bare optical fiber, 5, an optical fiber grating, 6 and an optical fiber sensing demodulator.
Detailed Description
The present invention will be described with reference to the accompanying drawings.
As shown in fig. 1, the optical fiber type rock stress sensor includes an armored optical cable 1, a rock cylinder 2, a bare optical fiber 4 and an optical fiber sensing demodulator 6, wherein the bare optical fiber 4 is arranged inside the rock cylinder 2, the armored optical cable 1 is arranged at an inlet end of the rock cylinder 2, one end of the armored optical cable 1 is connected with the bare optical fiber 4, and the other end is connected with the optical fiber sensing demodulator 6; the rock cylinder 2 is a cylindrical rock body taken from a rock area to be detected, an axial blind hole is formed in the center of the end part of the rock cylinder 2, and the rock cylinder 2 is taken from the area to be detected so as to reduce the matching error with a rock medium; the bare fiber 4 is arranged in the blind hole and is encapsulated and cured through the epoxy resin 3, and the arrangement of the epoxy resin 3 can enable the fiber grating 5 to be better attached to the inside of the blind hole and carry out protection encapsulation; and the fiber core of the bare fiber 4 is also provided with a fiber grating 5.
The fiber bragg grating 5 is a Fiber Bragg Grating (FBG) manufactured on the bare fiber 4, so that the sensor has the excellent characteristics of electromagnetic interference resistance, corrosion resistance and water resistance, and can be used in severe environments.
The end face of the tail end of the rock column body 2 is a pressure-sensitive face.
The fiber grating 5 is parallel to the axial position of the rock cylinder 2.
When the stress sensor is used for testing, holes are drilled in the rock, the stress sensor is embedded in the rock to be tested, when the rock cylinder 2 is compressed and deformed under the action of stress in rock media, the optical fiber grating 5 in the rock cylinder is driven to deform, the armored optical cable 1 is connected with a matched optical fiber sensing demodulator 6, a strain sensing signal of a Bragg grating FBG is demodulated and output, and the rock stress value is converted through a pre-calibrated pressure sensitive coefficient.
The part of the utility model not detailed is prior art.
Claims (4)
1. The utility model provides an optical fiber formula rock stress sensor, includes armor optical cable (1), rock cylinder (2), bare fiber (4) and optical fiber sensing demodulation appearance (6), characterized by: the bare fiber (4) is arranged inside the rock cylinder (2), the armored optical cable (1) is arranged at the inlet end of the rock cylinder (2), one end of the armored optical cable (1) is connected with the bare fiber (4), and the other end of the armored optical cable is connected with the optical fiber sensing demodulator (6); the rock column (2) is a columnar rock body taken from a rock area to be detected, and an axial blind hole is formed in the center of the end part of the rock column (2); the bare optical fiber (4) is arranged in the blind hole and is encapsulated and cured by epoxy resin (3); and the fiber core of the bare fiber (4) is also provided with a fiber grating (5).
2. A fibre-optic rock stress sensor according to claim 1, wherein: the fiber bragg grating (5) is a Fiber Bragg Grating (FBG) manufactured on the bare fiber (4).
3. A fibre-optic rock stress sensor according to claim 1, wherein: the end face of the tail end of the rock column body (2) is a pressure-sensitive face.
4. A fibre-optic rock stress sensor according to claim 1, wherein: the fiber bragg grating (5) is parallel to the axial position of the rock cylinder (2).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202020007279.7U CN211013323U (en) | 2020-01-03 | 2020-01-03 | Optical fiber type rock stress sensor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202020007279.7U CN211013323U (en) | 2020-01-03 | 2020-01-03 | Optical fiber type rock stress sensor |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN211013323U true CN211013323U (en) | 2020-07-14 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202020007279.7U Active CN211013323U (en) | 2020-01-03 | 2020-01-03 | Optical fiber type rock stress sensor |
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| CN (1) | CN211013323U (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113532706A (en) * | 2021-08-02 | 2021-10-22 | 广东电网有限责任公司中山供电局 | Optical fiber sensor for detecting optical cable light path |
-
2020
- 2020-01-03 CN CN202020007279.7U patent/CN211013323U/en active Active
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113532706A (en) * | 2021-08-02 | 2021-10-22 | 广东电网有限责任公司中山供电局 | Optical fiber sensor for detecting optical cable light path |
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