CN209085551U - Multi-point type optical fiber grating bottom hole strain gauge - Google Patents
Multi-point type optical fiber grating bottom hole strain gauge Download PDFInfo
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Abstract
The utility model discloses a kind of multi-point type optical fiber grating bottom hole strain gauges, including measurement conical section, glue storage cavity body and piston rod portion；Measuring conical section includes fiber Bragg grating strain sensor, plastic hole and binder retaining ring, glue storage cavity body and pin hole, and fiber Bragg grating strain sensor is pasted on conical rubber cap outer wall, and lead is laid in wire lead slot；It is moved by piston rod to glue storage cavity body direction and squeezes out the glue in glue storage cavity body from lower end plastic hole, fiber Bragg grating strain sensor is posted on bellmouth bed rock body, is deformed together with surrounding rock body, obtain strain of rock mass information during stress relieving.The utility model has many advantages, such as that anti-electromagnetic interference capability is strong, good corrosion resistance, precision small in size are high, measurement range is big, number of leads is few, transmission range is long, and structure is simple, size is smaller, Rock Mass Integrality is required low, installation is quick and convenient with measurement procedure, may be implemented to install the bottom hole strain measurement in sub-aperture in Φ 76mm.
Description
Technical field
The utility model relates to geophysics rock mass stress fields of measurement, specifically, being related to a kind of multi-point type optical fiber light
Gate hole bottom strain gauge.It is mainly used in the geostress survey field based on set core stress relieving method, function is using laying
Multiple fiber Bragg grating strain sensors with temperature compensation unit on nose cone, measuring unit core process are drawn due to stress relieving
The strain of sub-aperture bottom hole and its variation risen, through hole bottom strain measurement Stress calculation principle and formula find out the original place around aperture
Stress state.
Background technique
Geostress survey is the mechanics basic parameter for measuring Solid Geophysics phenomenon behind physical mechanism, in underground tunnel
Using very extensive in the Geological Engineerings such as road, railway, highway, mining engineering country rock, high slope and ground excavation.With the mankind couple
The increase of the energy and mineral resources demand and continuing to increase for mining rate, superficial part mineral resources are increasingly reduced, domestic and international mine
Mountain all subsequently enters deep resource development status, and " three high " problem (high-ground stress, High-geotemperature, the height encountered in deep mining
Hydraulic pressure) focus in Rock Mechanics In Deep Mining Engineering research and difficulties (what full sea etc., 2005) will be become.It is accurate to determine deep
The crustal stress spatial-temporal distribution characteristic and rule in development space region are one of necessary ways for solving the above problem and geology work
The research of journey Problem stability and design analysis, the prerequisite for realizing the geotechnical engineering scientification of decision-making, therefore geostress survey is managed
By the research of, method and technique, there is important scientific meaning.
The observation and estimation of MAFIC ROCKS IN DEEP CRUST stress state are an important difficulties of crustal stress actual measurement work, Cong Diying
Power concept proposes that so far, the tens of kinds of detecting earth stress methods that scientists from all over the world propose are sorted out according to its data source, probably may be used
To be divided into five major class: the method based on core, the method based on drilling, Geologic method, geophysical method (or seismology side
Method), method based on the underground space (Hill et al., 1994；Amadei and Stephasson, 1997).On these ground
In method for measuring stress, only over-coring stress relief method and hydraulic fracturing can provide principal stress size and the side of horizontal stress
To remaining earth stress measuring method is only capable of providing principal direction of stress, cannot provide principal stress size.Over-coring stress relief method conduct
A kind of geostress survey common method based on drilling, by monitoring core from parent rock release during strain and change
Shape, and then inverting Original strata stress field.This method can pass through the one-shot measurement in a drilling, so that it may determine that the three-dimensional of rock mass is answered
Power state crosses stress measurement without three holes, is generally acknowledged most effective triaxiality measurement method.
Over-coring stress relief method is grown up based on plane strain overcoring method, and Hast discloses him for the first time within 1958
It is utilized during 1952-1953 in Sweden La Yisiwaer (Laiswall) lead ore and four, Scandinavian Peninsula mining area
The resulting drilling hole stress measurement result of magnetic inductance method crustal stress measurer is pressed, the shock of people is caused.From Hast public affairs in 1958
After its research achievement of cloth, drilling hole stress measuring technique is all developed energetically and developed in countries in the world.By domestic and foreign scholars' many decades
Research, a set of standardized process of measurement has been formed at present, using opposite more square with other test method with measurement process
Just, and measuring device bulking value is smaller, becomes that applicability is most strong and one of the highest earth stress measuring method of reliability.
Different with the physical quantity of measurement according to measuring cell installation, set core stress relieving mensuration can be divided into borehole wall again
Strain measurement method, boring aperture deformation measurement method and three kinds of drilling hole bottom strain measurement method (Cai Meifeng, 2000), pass through respectively
The strain of releasing process middle hole wall, aperture deformation and bottom hole strain are monitored to calculate Original strata stress field.Borehole wall strain measurement method
Measuring cell resistance strain plate is affixed directly on drilling palisades, or measuring cell resistance strain plate is wrapped in ring
It is pasted again in oxygen resin-case on drilling palisades, carries out drilling three-dimensional strain measurement, realize that single hole tests resultant stress tensor.It should
Method measurement accuracy is high, but complicated for operation, requires height to tested Rock Mass Integrality, measurement success rate is lower.Boring aperture deformation
Mensuration principle is that the aperture to drill after stress relieving can change, and by recording this knots modification, is managed substantially using some
Indicate that the physical mathematics relational expression between each relevant variable is solved by being derived by, to obtain the measurement of rock stress
Method.This kind of measuring device has very much, but boring aperture deformation measurement method can only measure plane stress state, be unable to get
True three-dimension stress state.
The principle of bottom hole Strain Method is resistance strain plate to be pasted onto the plane of bottom hole position, and then sets of holes release rock
Core stress, measurement strain, to obtain the measurement method of borehole circumference triaxiality.The Typical Representative of this kind of measuring instrument has
" CSIR's door plug " bottom hole strain gauge (Leeman, 1964) that the Leeman in South Africa is developed, Japan Sugawara et al. development
Hemispherical-shaped aperture bottom strain gauge (Sugawara and Obara, 1986) and round taper hole bottom strain gauge (Sugawara etc.,
1999).16 or the 24 foil gauge round taper hole bottom strain gauges-CCBO bottom hole strain that especially Sugawara et al. is developed
Meter, can be by 16 to 24 foil gauge assembled units, can accurately and effectively the surface strain of testing bore holes conical lower portion is in turn
Original strata stress is obtained, testing time, energy and testing expense are effectively reduced.This method advantage is it to Rock Mass Integrality requirement
It is low, the sets of holes core grown is not needed very much, it is advantageous under large ground pressure as long as that section of bottom hole completely uses,
The region especially influenced by disc-shaped core, this method advantage is clearly, it is thus possible in relatively more broken rock mass.
However be measuring cell since existing bottom hole strain gauge is all based on traditional resistive foil gauge, and resistance-type strains
The generally existing interference vulnerable to test environment especially temperature factor in piece measurement, is specifically primarily present following problems:
1. the main strain measurement element of bottom hole deformeter, the resistance value of resistance strain plate is easy the change by ambient temperature
Change and generate nonlinear change, and it is larger non-linear to strain its resistance value to have greatly, thus its is affected by environment larger, moisture resistance
Wet and anti-interference ability is poor；
2. being lost greatly in transmission process since strain signal is reflected by resistance variations, it is not easy to acquire over long distances
And transmission, thus it is limited to fathom, and is not suitable for longhole survey.
3.16 foil gauges need 32 leads, and number of leads is more, lead is thick, are not easy to installation and aperture measuring.
In view of the above objective technique reason, it is highly desirable the bottom hole strain based on new sensor technology research and development a new generation
Instrument.
Fiber grating (FBG:Fiber Bragg Grating) sensing technology since being the 1990s it is emerging based on
The sensing technology of optical fiber passive Sensitive Apparatus, due to the wavelength that its sensitive variable parameter is light, because without light source, transmission line
The interference of the factors such as loss, has excellent temperature and strain-responsive characteristic, extensive application prospect, and FBG is to utilize doping
The light sensitivity of (such as germanium, phosphorus) optical fiber, the technology make the doping in extraneous incident photon and fibre core by the method for U-V writing
Particle interaction causes the refractive index of fiber core that axial cyclic or acyclic permanent change occurs, in fibre core
Interior formation space phase grating.The basic principle of FBG sensing as shown in Figure 1, when the incident light beam strikes of a branch of wide range are to FBG,
According to grating theory, in the case where meeting Bragg condition, will be totally reflected, reflectance spectrum is in Bragg wavelength XB
There is peak value in place, and has λB=2neffΛ, wherein neffFor the effective refractive index of fibre core, Λ is period (the i.e. grid of variations in refractive index
Away from), the reflectance spectrum and transmitted spectrum characteristic of fiber grating are as shown in Figure 1.
When fiber grating external physical field, (such as ess-strain, temperature) changes, pitch Λ becomes therewith
Change, to change the wavelength of grating back reflected laser.Become according to the wavelength of fiber Bragg grating strain sensor made of this principle
The expression formula changed between strain has: Δ λB=(1-Pε)ε·λB, wherein PεIt is true by the material of fiber grating for elasto-optical coefficient
It is fixed.Therefore, the changes delta λ of grating Bragg wavelength in reflection signal is only detectedB, can be detected strain variation to be measured.
Fiber Bragg Grating technology also has the advantage that other than having the advantages of general optical fiber sensing technology
1. it is strong antijamming capability, good corrosion resistance, small in size, there are very high reliability and stability；
2. measurement sensitivity is high, high resolution, precision are high, there is good repeatability；
3. dynamic range is big, good linearity, energy self calibration can be used for the absolute measurement to extraneous parameter；
4. multiple sensors can be integrated in an optical fiber, it is reusable, convenient for constituting various forms of Fibre Optical Sensors
Device network realizes distributed measurement；
5. being convenient for remote monitoring, it can be made into intelligence sensor, be widely used；
6. structure is simple, the service life is long, maintenance, extension and installation easy to repair etc..
The technology has had relatively broad application in geotechnical engineering health monitoring field, but changes in crustal stress and observe
Aspect is related to less, more only based on the stress strain gauge of optical fiber sensing technology, lacks the crustal stress based on the technology
Bottom hole strain monitoring technique study.The above-mentioned characteristic of fiber grating is particularly adapted to the strain of the bottom hole in over-coring stress relief method and surveys
Amount field, thus the utility model has developed the bottom hole strain measurement technique in detecting earth stress based on Fiber Bragg Grating technology, grinds
The multipoint mode bottom hole strain gauge based on the fiber Bragg grating strain sensor with temperature compensation unit is sent out, is realized to set core stress relieving
The high-precision detection of method mesoporous bottom strain.
Utility model content
The utility model is precisely in order to a kind of multi-point type optical fiber grating bottom hole strain for solving above-mentioned technical problem and designing
Meter.It is answered by utility model multi-point type optical fiber grating (FBG) bottom hole strain gauge to carry out the bottom hole based on over-coring stress relief method
Become test job, maximum outside diameter is the cone of 50mm, meets the measurement request in 76mm drilling, and measurement accuracy reaches
0.5%FS.Fiber Bragg grating strain sensor using multipoint mode with temperature compensation unit, is fixed in tapered wall, passes through
Sensor is pasted bottom hole by epoxide-resin glue, by Sensor Data Record and is stored in conjunction with aperture fiber Bragg grating (FBG) demodulator, real
Bottom hole strain measurement during now set core stress relieving.
The technical scheme adopted by the utility model to solve the technical problem is as follows:
1, multi-point type optical fiber grating (FBG) bottom hole strain gauge Design of Main Structure
Multi-point type optical fiber grating (FBG) bottom hole strain gauge main structure described in the utility model consists of three parts, respectively
It is measurement conical section, glue storage cavity body and piston rod portion.The structure composition of multi-point type optical fiber grating (FBG) bottom hole strain gauge is shown
It is intended to as shown in Figure 2.Measuring conical section includes fiber Bragg grating strain sensor, plastic hole and binder retaining ring, glue storage cavity body
And pin hole, fiber Bragg grating strain sensor are pasted on conical rubber cap outer wall, Optical Fiber Winding is in upper groove and lower groove
Interior, lead is laid in wire lead slot；There is the attachment device with finder, mounting rod in piston rod upper end, and the upper end is equipped with installation
Positioning pin nail hole and wire lead slot, by rotational installation bar realize mounting rod and the connection of piston rod with separate；By piston rod to
Glue in glue storage cavity body is squeezed out and is compacted from lower end plastic hole by the movement of glue storage cavity body direction, and fiber Bragg grating strain sensor is turned
It is attached on bellmouth bed rock body, is deformed together with surrounding rock body, obtain strain of rock mass information during stress relieving.
2, sensor layout scheme
Fiber Bragg grating strain sensor uses multipoint mode mounting means, as shown in figure 3, totally 8 groups of optical fiber in measurement cone
Grating strain transducer, along measurement cone even circumferential distribution, i.e. 45 ° of adjacent spaces, every group has 2 fiber grating strains to pass
Sensor, the angle with ρ axis are respectively 0 °, 90 °.
The laying of fiber Bragg grating strain sensor and connection type such as Fig. 4 and Fig. 5: utilize 2 sensor fibres by 16 light
2 groups of fiber grating strain transducer point is connected in series, wherein vertical ρ axis direction is that circumferential fiber Bragg grating strain sensor is
A group, 1 fiber Bragg grating strain sensor of every installation groove winding on it, one circle, then installs next fiber grating strain
Sensor；It is wherein B group along the fiber Bragg grating strain sensor of ρ axis direction, each fiber Bragg grating strain sensor is according to drawing
From upper groove, lower groove, alternately one circle of winding, 2 groups of fiber Bragg grating strain sensors measure circumferential direction ε to line position respectively respectivelyθAnd axis
To ερStrain is convenient for data analysis.
3, Sensor Temperature Compensation
Fiber Bragg grating strain sensor is the strain transducer with temperature compensation unit, temperature calibration and compensation method
It is: before fiber Bragg grating strain sensor is mounted on measurement cylinder, fiber Bragg grating strain sensor unit is first placed in perseverance
Temperature calibration experiment is carried out in the case of warm water domain, and the experimental data of wavelength with temperature variation is fitted, handled and analyzed, is passed through
Temperature calibration tests to obtain the temperature sensitivity coefficient of strain sensing unit, and then passes in set core stress relieving actual measurement to strain
Sense cell temperature compensates；There is a not strained influence inside fiber Bragg grating strain sensor with temperature compensation unit
Temperature-sensitive grating, it acts as monitoring variation of ambient temperature Δ T, there is Δ T=(λt1-λt0)/R1, in formula: λt0For the first of temperature-sensitive grating
Beginning wavelength；λt1For t1The wavelength at moment；R1For the temperature sensitivity of temperature-sensitive grating；Environment temperature Δ T causes fiber grating strain
Sensor wavelength changes, variation delta λsAre as follows: Δ λs=RsΔ T, R in formulasFor the temperature sensitivity of strain sensing unit；It will
The wavelength X that (FBG) demodulator demodulates subtracts wavelength change caused by temperature, finally obtains fiber Bragg grating strain sensor and answers in set core
Wavelength during power releasing are as follows: λs=λ-Δ λs, wherein λ is t1The fiber grating strain that moment wavelength demodulation device demodulates passes
Sensor wavelength.
The beneficial effects of the utility model are: a kind of multi-point type optical fiber grating bottom hole strain gauge is anti-for resistance strain plate
The deficiencies of interference performance and long distance transmission are lost place, proposes the fiber grating strain sensor based on multipoint mode with temperature-compensating
The crustal stress bottom hole strain detecting method of device, and develop fiber grating bottom hole strain gauge.The utility model has electromagnetism interference
The advantages that ability is strong, good corrosion resistance, precision small in size are high, measurement range is big, number of leads is few, transmission range is long, and structure
Simply, size is smaller, low to Rock Mass Integrality requirement, and installation is quick and convenient with measurement procedure, may be implemented to install in Φ 76mm
Bottom hole strain measurement in sub-aperture.
Detailed description of the invention
Fig. 1 is the reflectance spectrum and transmitted light spectrogram of grating.
Fig. 2 multi-point type optical fiber grating bottom hole strain gauge structure composition schematic diagram.
Fig. 3 fiber Bragg grating strain sensor mounting means schematic diagram.
Fig. 4 fiber Bragg grating strain sensor layout diagram.
Fig. 5 fiber Bragg grating strain sensor two-expanded view of layout diagram
Fig. 6 is one of set core stress relieving bottom hole Strain Method geostress survey step schematic diagram-set core macropore.
Fig. 7 is the two-installation apertures for covering core stress relieving bottom hole Strain Method geostress survey step schematic diagram.
Fig. 8 is the three-strain transducers installation for covering core stress relieving bottom hole Strain Method geostress survey step schematic diagram.
Fig. 9 is the four-set rock drilling cores for covering core stress relieving bottom hole Strain Method geostress survey step schematic diagram.
Figure 10 is one of multi-point type optical fiber grating bottom hole strain gauge strain testing result.
Figure 11 is the two of multi-point type optical fiber grating bottom hole strain gauge strain testing result.
Specific embodiment
The present invention will be further described with reference to the accompanying drawings and examples.
Referring to fig. 2, multi-point type optical fiber grating (FBG) bottom hole strain gauge structure composition schematic diagram described in the utility model, figure
In 1 be conical rubber cap, 2 be fiber Bragg grating strain sensor, and 3 be plastic emitting aperture, and 41 be upper groove, and 42 be lower groove, and 5 are
Binder retaining ring, 6 be glue storage cavity body, and 7 be pin hole, and 8 be piston rod, and 9 be wire lead slot, and 10 be installation positioning pin nail hole.Respectively
It is measurement conical section 1-5,8 part of glue storage cavity body 6 and piston rod.Fiber Bragg grating strain sensor 2 is pasted onto conical rubber in advance
On 1 outer wall of Capsule, in upper groove 41 and lower groove 42, lead is laid in wire lead slot 9 Optical Fiber Winding；Binder is stored in
In glue room 6, is moved by piston rod 8 to 6 direction of glue storage cavity body and the glue in glue storage cavity body 6 is squeezed out and pressed from lower end plastic hole 3
It is real, fiber Bragg grating strain sensor 2 is posted on bellmouth bed rock body；8 upper end of piston rod is equipped with installation positioning pin nail hole 10
With wire lead slot 9, by rotational installation bar realize mounting rod and the connection of piston rod with separate；It (is generally needed after binder solidification
Want 4~12h), fiber Bragg grating strain sensor 2 and bottom hole are securely cementing, take out mounting rod, start to cover core releasing, fiber grating
Strain transducer 2 deforms together with surrounding rock body, obtains strain of rock mass information during stress relieving.
Fiber Bragg grating strain sensor 2 uses multipoint mode mounting means, and space layout is as shown in figure 3, in measurement cone
Totally 8 groups of fiber Bragg grating strain sensors 2, along measurement cone even circumferential distribution, i.e. 45 ° of adjacent spaces, every group has 2 optical fiber
Grating strain transducer 2, the angle with ρ axis are respectively 0 °, 90 °.
The multi-point type optical fiber grating bottom hole strain gauge, the connection type of fiber Bragg grating strain sensor (2): be according to
It is divided into two groups of A, B (such as Fig. 4, Fig. 5) with the angle of ρ axis, is divided 16 fiber Bragg grating strain sensors 2 using 2 sensor fibres
2 groups are connected in series, wherein it is A group, 1 optical fiber of every installation that vertical ρ axis direction, which is circumferential fiber Bragg grating strain sensor,
One circle of the winding of groove 41 on it of grating strain transducer 2, then installs next fiber Bragg grating strain sensor；Wherein along
The fiber Bragg grating strain sensor 2 of ρ axis direction is B group, and each fiber Bragg grating strain sensor is according to wire locations respectively from upper
Alternately one circle of winding, 2 groups of fiber Bragg grating strain sensors 2 measure circumferential direction ε respectively for groove 41, lower groove 42θWith axial ερStrain,
It is convenient for data analysis.
The multi-point type optical fiber grating bottom hole strain gauge, fiber Bragg grating strain sensor 2 are with temperature compensation unit
Strain transducer, temperature calibration are with compensation method: before fiber Bragg grating strain sensor 2 is mounted on measurement cylinder, first
Fiber Bragg grating strain sensor Unit 2 is placed in progress temperature calibration experiment in the case of constant temperature waters, wavelength with temperature is changed
Experimental data be fitted, handle and analyze, test to obtain the temperature sensitivity system of strain sensing unit by temperature calibration
Number, and then strain sensing unit temperature is compensated in set core stress relieving actual measurement；Optical fiber light with temperature compensation unit
There is the temperature-sensitive grating of a not strained influence inside grid strain transducer, it acts as monitoring variation of ambient temperature Δ T, there is Δ
T=(λt1-λt0)/R1, in formula: λt0For the initial wavelength of temperature-sensitive grating；λt1For t1The wavelength at moment；R1For the temperature of temperature-sensitive grating
Sensitivity；Environment temperature Δ T causes fiber Bragg grating strain sensor wavelength shift, variation delta λsAre as follows: Δ λs=RsΔ T, formula
Middle RsFor the temperature sensitivity of strain sensing unit；The wavelength X that (FBG) demodulator is demodulated subtracts wavelength change caused by temperature, most
Wavelength of fiber Bragg grating strain sensor during covering core stress relieving is obtained eventually are as follows: λs=λ-Δ λs, wherein λ is t1Moment
The fiber Bragg grating strain sensor wavelength that wavelength demodulation device demodulates.
Embodiment:
The utility model multi-point type optical fiber grating bottom hole strain gauge uses for reference the main structure of CCBO bottom hole strain testing instrument,
Maximum outside diameter is 50mm, entire length 100mm.When it carries out set core stress relieving bottom hole strain measurement method measurement crustal stress, survey
It is as Figure 6-9 to measure step.A drilling is drilled through at measuring point first to predetermined depth (generally higher than tunnel diameter) (such as Fig. 6),
Then the aperture (such as Fig. 7) for being 280mm or so with special conical drill bit drilling depth.5~10 ° of updip of drilling is in order to rock powder
It is discharged with mud.Aperture is cleaned and wiped with clear water, cotton yarn and acetone, it will be clean in hole.
Measurement drilling, sub-aperture pore-forming and preparation it is ready after, by the binder being stirred inject glue room in, will measure
Cone and piston portion are fixed by pin, record the first time initial value of multiple spot fiber Bragg grating strain sensor.With with orientation
Fiber grating bottom hole strain gauge is sent into measurement sub-aperture (such as Fig. 8) by the mounting rod of device.
It after strain gauge is sent to predetermined position, forcibly drives mounting rod and worms, binder is from cavity aperture stream at this time
Into between gaging hole and the hole of element, second of initial value of multiple spot fiber Bragg grating strain sensor is recorded again.
(4~12h is generally required) after to be bonded dose of solidification, keeps element and bottom hole securely cementing, and record FBG sensor
Angle, then take out direction finder, sensor fibre be successively pierced by from basket, drilling rod and the tee tube of the rear part, connecting hole
Mouth fiber Bragg grating (FBG) demodulator, and record the final initial value of grating strain transducer.Several minutes of bath, after reading strain is stablized,
It can carry out set core and release (such as Fig. 9), the measurement of grating strain transducer is carried out during covering core, set core is read every 0.5cm
Number is primary, and record fiber Bragg grating (FBG) demodulator reading, (drilling depth about 100mm to 200mm) stops set when not changing with drilling depth wait read
Core.After covering core, the core for having strain gauge is taken out.Planar calibration is carried out, is finally read measurement using special-purpose software
Number is converted to crustal stress.
The in vitro Original strata stress test experiments of this set equipment are tested, and application effect is good.Multipoint mode light
Measured and record the strain curve of fine grating (FBG) bottom hole strain gauge.By Figure 10 and 11 it is found that 16 shown in figure
Channel signal, steady smooth, strong antijamming capability are very ideal.
The utility model is not limited to above-mentioned preferred forms, anyone obtained under the enlightenment of the utility model its
His any product identical or similar with the utility model, all falls within the protection scope of the utility model.
Claims (3)
1. a kind of multi-point type optical fiber grating bottom hole strain gauge, including measurement conical section, glue storage cavity body (6) and piston rod (8) portion
Point, there is the attachment device with finder, mounting rod in piston rod (8) upper end, and the upper end is equipped with installation positioning pin nail hole (10) and draws
Wire casing (9), by rotational installation bar realize mounting rod and the connection of piston rod with separate；It is characterized by: measurement conical section
Including fiber Bragg grating strain sensor (2), plastic hole (3) and binder retaining ring (5), glue storage cavity body (6) and pin hole (7), light
Fiber grating strain transducer (2) is pasted on conical rubber cap (1) outer wall, and Optical Fiber Winding is in upper groove (41) and lower groove
(42) in, lead is laid in wire lead slot (9)；It is moved to glue storage cavity body (6) direction by glue storage cavity body by piston rod (8)
(6) glue in is squeezed out from lower end plastic hole (3), fiber Bragg grating strain sensor (2) is posted on bellmouth bed rock body, with week
Country rock body deforms together, obtains strain of rock mass information during stress relieving.
2. multi-point type optical fiber grating bottom hole strain gauge according to claim 1, it is characterised in that: fiber grating strain sensor
Device (2) is using single section multipoint mode mounting means, and totally 8 groups of fiber Bragg grating strain sensors (2), edge measure cone in measurement cone
The distribution of body even circumferential, i.e. 45 ° of adjacent spaces, every group has 2 fiber Bragg grating strain sensors (2), distinguishes with the angle of ρ axis
It is 0 °, 90 °.
3. multi-point type optical fiber grating bottom hole strain gauge according to claim 2, it is characterised in that: fiber grating strain sensor
The connection type of device (2): 16 fiber Bragg grating strain sensors (2) point being connected in series for 2 groups using 2 sensor fibres,
It is A group, 1 fiber Bragg grating strain sensor (2) of every installation that wherein vertical ρ axis direction, which is circumferential fiber Bragg grating strain sensor,
One circle of groove (41) winding on it, then installs next fiber Bragg grating strain sensor；Wherein along the optical fiber of ρ axis direction
Grating strain transducer (2) be B group, each fiber Bragg grating strain sensor (2) according to wire locations respectively from upper groove (41),
Alternately one circle of winding, 2 groups of fiber Bragg grating strain sensors (2) measure circumferential direction ε to lower groove (42) respectivelyθWith axial ερStrain, is convenient for
Carry out data analysis.
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN110595657A (en) * | 2019-09-23 | 2019-12-20 | 煤炭科学技术研究院有限公司 | Small-aperture 16-component conical strain gauge |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN110595657A (en) * | 2019-09-23 | 2019-12-20 | 煤炭科学技术研究院有限公司 | Small-aperture 16-component conical strain gauge |
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