CN109556642A - A kind of fibre optical sensor for concrete structure crack monitoring - Google Patents
A kind of fibre optical sensor for concrete structure crack monitoring Download PDFInfo
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- CN109556642A CN109556642A CN201811259244.6A CN201811259244A CN109556642A CN 109556642 A CN109556642 A CN 109556642A CN 201811259244 A CN201811259244 A CN 201811259244A CN 109556642 A CN109556642 A CN 109556642A
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Classifications
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
- G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
- G01D5/26—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light
- G01D5/32—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light
- G01D5/34—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells
- G01D5/353—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells influencing the transmission properties of an optical fibre
- G01D5/35338—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells influencing the transmission properties of an optical fibre using other arrangements than interferometer arrangements
- G01D5/35341—Sensor working in transmission
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B11/00—Measuring arrangements characterised by the use of optical techniques
- G01B11/14—Measuring arrangements characterised by the use of optical techniques for measuring distance or clearance between spaced objects or spaced apertures
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Abstract
The invention discloses a kind of fibre optical sensors for concrete structure crack monitoring, including opposite the first capillary tubing and the second capillary tubing set gradually of nozzle, the bare fibre after the doubling of both ends is sequentially passed through in first capillary tubing and the second capillary tubing, the fibre-optical bending section of bare fibre is located at outside the first capillary tubing, two ends of bare fibre are located at the outside of the second capillary tubing, wherein, bare fibre inside the second capillary tubing is fixed as one with the second capillary tubing inner wall, first capillary tubing and the second capillary tubing bore are 1.5~3mm, it is poor that the present invention solves fibre optical sensor sensitivity existing in the prior art, the poor problem of monitoring effect is occurred to minute crack.
Description
Technical field
The invention belongs to fiber optic sensor technology fields, and in particular to a kind of optical fiber for concrete structure crack monitoring
Sensor.
Background technique
Crack is the important indicator for judging concrete structure health status, and the presence in crack will directly destroy the entirety of structure
Property, it is also possible to cause inside configuration steel bar corrosion, threatens the safe operation of structure.Therefore, crack is monitored accurately and in time
Occur, the state of development for monitoring crack in real time is particularly important.And in practical projects, different buildings and different operating environment make
There are the monitoring of its fracture different requirements should just cause enough attention when there is minute crack for some concrete structures,
Corresponding engineering measure is taken in time, and this requires sensor sensitivity with higher, monitor the generation in crack in time；And it is right
For other concrete structures, minute crack influences less structure safe operation, but fracture opening degree is needed to be held
Continuous monitoring prevents crack progressing to having dangerous aperture, this needs sensor to go back under conditions of guaranteeing certain sensitivity
There should be biggish range.Therefore, it is necessary to be suitable for the different actual crack sensors of engineering for research.And traditional electrical measurement
The generally existing durability of sensor is poor, vulnerable to electromagnetic interference, installation difficulty is big, range and sensitivity are single the disadvantages of, it is difficult to
Meet the different actual detection requirements of engineering.In recent years, fibre optical sensor with its light weight, electrical isolation, electromagnetism interference and
The advantages that corrosion-resistant, receives the extensive concern of domestic and foreign scholars[1-9]。
The different modes that fibre optical sensor is modulated in a fiber by light wave can be divided into: intensity modulation type, phase modulation-type,
The several types such as polarization state modulation type, frequency modulation(PFM) type and wavelength modulation type[10].Light wherein based on bending loss of optical fiber principle
Fine crack sensors belong to intensity modulation optical fiber sensor, and bending loss of optical fiber is that the bending radius of optical fiber is less than facing for optical fiber
Added losses caused by boundary's bending radius.In recent years, with the continuous deepening of research, the optical fiber based on bending loss of optical fiber principle
Sensor has achieved lot of research in terms of structural cracks and displacement monitoring.In those early years, there is scholar considering respectively
In the case where kind bending radius, fiber turns number, additional bending angle and wavelength, a kind of simple fibre optical sensor bending is proposed
Loss calculation formula, and coincide preferably with experimental data, and give the simplified formula of fiber bend loss sensitivity[11].Lee
River etc.[12]A kind of two-way strain-displacement sensor of distribution type fiber-optic is proposed, optical-fiber deformation is pasted on by measurement using OTDR
The bending loss of optical fiber of on piece obtains the dependent variable or displacement of measurement point, and it is 3mm that sensor displacement, which monitors range,.It is close several
Year, Luo Zhihui etc.[13]By mode fiber spiral being wrapped on cutting rubber bar, propose a kind of wide range distribution light
Fiber sensor positions displacement using OTDR and position and analysis displacement occurs, and sensor maximum range is 17mm, but sensor
Precision and survival rate are affected by embedded technique.Packet rapid development etc.[14]It is curved by the way that unprotected Optical Fiber Winding to be formed by knots tied
Song devises a kind of novel wide range crack fibre optical sensor, which is based on bending loss of optical fiber principle, can be to concrete
Structural cracks carries out duration monitoring, but there is a problem of that sensitivity is poor, poor to the generation monitoring effect of minute crack.Journey
Beautiful jade etc.[15]A kind of gear drive type optical fibre displacement sensor is proposed, so that being in good line between bending loss of optical fiber and displacement
Sexual intercourse, but sensitivity limited by Optical Fiber Winding shaft diameter it is larger.Li Minghao etc.[16]Based on bending loss of optical fiber principle, propose
A kind of U-shaped wound form optical fibre displacement sensor, the sensor theory range is up to 120mm, but in actual use due to light
Fine to be in tensional state always, in larger displacement, optical fiber is easily pulled off.
Deficiency based on the above optical fiber crack sensors in practical applications, the present invention is based on bending loss of optical fiber principle,
A kind of sensitivity and the controllable fibre optical sensor of range are proposed, sensor has been determined by the experiment of poly (methyl methacrylate) plate simulation fracture
Technical indicator, and by experiment sensor performance is tested, have rated the working performance of sensor.
Summary of the invention
The object of the present invention is to provide a kind of fibre optical sensors for concrete structure crack monitoring, solve existing skill
Fibre optical sensor sensitivity present in art is poor, the poor problem of monitoring effect occurs to minute crack.
The technical scheme adopted by the invention is that a kind of fibre optical sensor for concrete structure crack monitoring, special
Sign is, including opposite the first capillary tubing and the second capillary tubing set gradually of nozzle, the first capillary tubing and second mao
The fibre-optical bending section of bare fibre after sequentially passing through both ends doubling in fine steel tube, bare fibre is located at outside the first capillary tubing, naked
Two ends of optical fiber are located at the outside of the second capillary tubing, wherein the bare fibre inside the second capillary tubing and second
Capillary tubing inner wall is fixed as one.
The features of the present invention also characterized in that
It is provided with pedestal on first capillary tubing and the second capillary tubing tube wall, screw hole, the first capillary are provided on pedestal
Steel pipe and the second capillary tubing are fixed at measurement position by the screw hole on pedestal with screw fit.
First capillary tubing and the second capillary tubing bore are 1.5~3mm.
The determinant of fibre-optical bending section is bending diameter, and bending diameter range is 5mm~26mm.
Bare fibre inside the second capillary tubing is adhesively fixed with the second capillary tubing inner wall by epoxide-resin glue.
The invention has the advantages that for concrete structure crack monitoring fibre optical sensor, the first capillary tubing and
Second capillary tubing is individually fixed in crack two sides, and when crack occurs, the first capillary tubing and the second capillary tubing will be with
Crack two sides concrete is mobile to two sides, and since bare fibre is fixed in the second capillary tubing, crack developing will pull the first capillary
Bare fibre in steel pipe becomes smaller so as to cause fibre-optical bending section bending size；After crack occurs, if being issued in external load action
Raw closure, two sections of capillary tubings will be close to each other, and due to mechanical characteristics of optical fi, fibre-optical bending section is bent size will be gradually
Restore.The change in size of fibre-optical bending section can cause the variation of light loss value at this, use light power meter or optical time domain reflectometer
This change procedure can be monitored, to realize the monitoring of fracture.
Detailed description of the invention
Fig. 1 is a kind of structural schematic diagram of the fibre optical sensor for concrete structure crack monitoring of the present invention；
Fig. 2 is to verify a kind of experiment system that the fibre optical sensor for concrete structure crack monitoring is built of the present invention
System structure chart；
Fig. 3 is light loss value and bending section diameter in a kind of fibre optical sensor for concrete structure crack monitoring of the present invention
Relational graph；
Fig. 4 is that light loss value and fracture width close in a kind of fibre optical sensor for concrete structure crack monitoring of the present invention
System's figure；
Fig. 5 is a kind of installation of fibre optical sensor for concrete structure crack monitoring of the present invention in practical applications
Figure.
In figure, 1. fibre-optical bending sections, 2. screw holes, 3. pedestals, 4. first capillary tubings, 5. second capillary tubings, 6. naked light
It is fine.
Specific embodiment
The following describes the present invention in detail with reference to the accompanying drawings and specific embodiments.
A kind of fibre optical sensor for concrete structure crack monitoring of the present invention, structure is as shown in Figure 1, include nozzle phase
To the first capillary tubing 4 and the second capillary tubing 5 set gradually, successively worn in the first capillary tubing 4 and the second capillary tubing 5
The fibre-optical bending section 1 of bare fibre 6 after crossing both ends doubling, bare fibre 6 is located at outside the first capillary tubing 4, and two of bare fibre 6
End is located at the outside of the second capillary tubing 5, wherein bare fibre 6 and the second capillary tubing inside the second capillary tubing 5
5 inner walls are fixed as one.
It is provided with pedestal 3 on 5 tube wall of first capillary tubing 4 and the second capillary tubing, is provided with screw hole 2 on pedestal 3, first
Capillary tubing 4 and the second capillary tubing 5 are fixed at measurement position by the screw hole 2 on pedestal 3 with screw fit.
First capillary tubing 4 and 5 bore of the second capillary tubing are 1.5~3mm.
The determinant of fibre-optical bending section 1 is bending diameter, and bending diameter range is 5mm~26mm.
Bare fibre 6 and 5 inner wall of the second capillary tubing inside the second capillary tubing 5 is solid by epoxy resin gluing knot
It is fixed.
A kind of fibre optical sensor for concrete structure crack monitoring of the present invention, design and working principle are as follows:
Bare fibre 6 is located at two ends connection monitoring device of the outside of the second capillary tubing 5, should with epoxide-resin glue
Section bare fibre 6 is encapsulated in the second capillary tubing 5, so that this section of optical fiber and capillary tubing is kept synchronizing moving, it is ensured that the two will not
It produces relative sliding.First capillary tubing 4 and the second capillary tubing 5 are individually fixed in crack two sides, when crack occurs, first
Capillary tubing 4 and the second capillary tubing 5 will be mobile to two sides with crack two sides concrete, due to naked in the second capillary tubing 5
Optical fiber 6 is fixed, and crack developing will pull the bare fibre 6 in the first capillary tubing 4, is bent size so as to cause fibre-optical bending section 1
Become smaller；After crack occurs, if being closed under external load action, two sections of capillary tubings will be close to each other, due to optical fiber
Mechanical property, fibre-optical bending section 1 be bent size will be gradually recovered.The change in size of fibre-optical bending section 1 can cause light at this
The variation of loss value can monitor this change procedure using light power meter or optical time domain reflectometer, to realize fracture
Monitoring.Main sensing principle are as follows: preset bending section optical fiber in the sensor, i.e., a previously given fibre loss value,
So that optical power is changed by changing bending section fiber size size, resettle fracture width and light loss relationship, thus real
Now to the monitoring of structural cracks.
In a kind of fibre optical sensor for concrete structure crack monitoring of the present invention, the reason of bending loss and fracture width
It is as follows by relationship:
After fibre-optical bending, it will occur to radiate along the energy in fiber bending radius direction, the conduction in original optical waveguide
Mould will become radiation mode, so as to cause bending loss.It is lost produced by bending of the bending curvature radius much larger than fibre diameter,
It is known as macrobend loss.The fibre optical sensor that the present invention designs is based on bending loss of optical fiber principle, utilizes fracture width direction
On stretching caused by bending section optical fiber curvature radius change, by light power meter detection fiber radius of curvature reduce caused by
Bending loss establishes the relationship between fracture width and bending loss of optical fiber, to realize the identification and quantitative measurment of fracture:
For step-index single-mode fibers, the bending loss in unit length can be indicated are as follows:
ac=AcR-1/2exp(-UR) (1)
In formula, R is optical fiber macrobend bilge radius, AcIt is amount relevant to optical fiber type and light source working state with U, specifically
Are as follows:
In formula: λ is operation wavelength, and λ c is cutoff wavelength, and Δ=(n1-n2)/n2 is fiber cores and cladding relative refractive
Difference, n1 are fiber core refractive index, and n2 is cladding index, and η and δ are constants related with fiber type, light source working wavelength.
By above-mentioned bending loss of optical fiber principle it is found that the bending section optical fiber of radii fixus can generate fixed loss, loss
Size is related with radius of curvature R, and bending section fiber radius R and fracture width Δ l are similarly one-to-one relationship.According to sensing
Device structure it can be concluded that bending section fiber radius and fracture width relationship are as follows:
In formula, a is bending section optical fiber initial radium, and α is the angle of optical fiber and capillary tubing, when bending section optical fiber is initially straight
When diameter determines, α is definite value.
Substituting the above to formula (1) can be obtained the relationship of sensor bending loss and fracture width are as follows:
Wherein, Δ LsCorresponding light loss value when for fracture width being Δ l, b are related with sensor bending section size
Constant.
A kind of fibre optical sensor for concrete structure crack monitoring of the present invention, experimental verification are as follows:
By above-mentioned bending loss of optical fiber characteristic it is found that when bending section size is larger, bending loss of optical fiber is very small, light
Changed power is difficult to be arrived by instrument monitoring, therefore, in order to ensure that sensor initial sensitivity with higher, the present invention pass through first
The changing rule of bending loss of optical fiber, has measured most sensitive diameter section under differently curved section of size of experimental study, it is determined that
The critical loss size of bending section optical fiber provides the installation warrants of bending section optical fiber original dimension for results of fracture simulation experiment.Then lead to
Cross the feasibility of experimental verification sensor.Experimental material and equipment specifically include that operation wavelength is 1550nm light source, optical power
Meter, crack sensors, micro-displacement adjust platform, poly (methyl methacrylate) plate etc..Poly (methyl methacrylate) plate and micro-displacement are adjusted platform to be fixed on
On experimental bench, two sections of capillaries are respectively adhered on by poly (methyl methacrylate) plate using epoxide-resin glue and micro-displacement is adjusted on platform, light
Fine one end connects light power meter, and the other end connects laser light source, recording optical power meter initial reading.It is adjusted by adjusting micro-displacement
The extension and closure in platform simulation crack and control critical eigenvalue, and record the numerical value and fracture width value of corresponding light power meter.It is real
Experiment device is as shown in Figure 2.In experiment, fracture width is gradually increased since 0mm, and fracture width minimum amount of feed 0.5mm is arranged.
Light loss value and bending section fibre diameter corresponding relationship experimental result is shown in Fig. 3:
As seen from Figure 3, when initial, bending section fibre diameter is larger, is 30mm, and optical power loss curve is a Duan Shui
Flat line, it is known that bending loss of optical fiber is smaller at this time to ignore；When bending section diameter reaches 26mm, light loss curve is one
Section ascending curve, the slope of curve increases with the reduction of radius, it is known that and bending section optical fiber starts to generate bending loss at this time, and with
The continuous reduction light loss of bending section fibre diameter persistently increase, but this stage light loss curve rises more gentle, loss
It is unobvious；When bending section diameter reaches 12mm, light loss curve rises obviously, is distributed in approximately linear, it is known that this stage light
Loss is very sensitive to fibre-optical bending diameter change, therefore the bending section size production sensor for choosing this stage is greatly improved
The sensitivity of sensor；When bending section fibre diameter reaches 5mm, since capillary caliber limits, bending section fibre diameter is not
Reduce again.Therefore, the light for being 1550nm for wavelength, the appreciable bending section fibre diameter range of light power meter are 5mm-
26mm, most sensitive section are 5mm-12mm, and the sensitivity for existing for flexibly controlling sensor of the sensitivity interval and range provide
Strong foundation.
Reduce since too small bending section initial diameter will lead to transducer range, in order to guarantee that sensor has
Higher initial sensitivity and biggish range, in the monitoring experiment of organic plates glass plate simulation fracture, bending section optical fiber is initial
Diameter is set as 12mm, and experimental result is shown in Fig. 4:
As seen from Figure 4, the change of optical power attenuation fracture width is very sensitive, and light loss value is with fracture width
Increase exponentially type increase, illustrate sensor to structural cracks have good monitoring capability.Simulation fracture in experimental result
Extension is essentially coincided with closure empirical curve, it is known that sensor can not only monitor the development process of structural cracks, can also monitor
The structural cracks closing course to caused by changing due to load.Experimental data and the theoretical fitting goodness of fit are very high in Fig. 4, obtain and work as
Semiempirical fitting formula when bending section optical fiber initial diameter is 12mm are as follows:
Load:
Unloading:
Average formula:
Calculation formula of the average formula (8) of modus ponens (6) and formula (7) as sensor.
This experiment demonstrates the feasibility and validity that sensor monitors crack by poly (methyl methacrylate) plate simulation fracture, passes
Sensor is good to 0.5mm grades of crack perceived effects, and maximum analog fracture width is 20mm in experiment, and corresponding bending section optical fiber is straight
Diameter is 5mm.Sensitivity and the different of range can be required according to engineering is practical in practical applications, control fibre-optical bending section ruler
It is very little, guarantee the safety of sensor while meeting different Crack Monitoring demands, it is proposed that bending section optical fiber minimum diameter is not less than
5mm。
Sensor performance test:
In practical projects, structural cracks is often as external loads are in cyclically-varying, therefore it is required that sensor has
Good stability and repeatability.By sensor structure it is found that bending section optical fiber keeps bending state may for a long time when in use
Plastic deformation can be generated, transducer sensitivity is influenced, destroys the long-time stability of sensor.Based on this, the present invention has carried out one
Series of slits extension and closure experiment, are loaded by the crack in the long period and unloading is tested, and can be carried out to sensors
Test.
Experimental provision is shown in Fig. 5, using the development and closure of two concrete block simulation concrete structural cracks, to realize counterincision
Micro-displacement adjusting platform is fixed on a concrete block top by the accurate control for stitching aperture, then by two capillarys in sensor
Steel pipe is pasted on micro-displacement and adjusts platform and another concrete block surface.Setting sensor bending section initial diameter in experiment
12mm, crack minimum amount of feed 5mm carry out 10 crack loads and unloading experiment, read each crack using light power meter and open
Spend corresponding optical power value, reading duration interval 30min.Experimental result is shown in Table 1:
1 light loss value of table and fracture width relation table
Experimental result is analyzed it is found that experimental result and confirmatory experiment result are almost the same, crack is same when loading and unloading
The corresponding optical power value of fracture aperture is held essentially constant, and maxima and minima difference is no more than 0.05dB.Light loss value it
Between maximum standard deviation be only 0.0218dB, show sensor have good long-time stability and repeatability.
A kind of fibre optical sensor for concrete structure crack monitoring of the present invention, experimental verification sensor it is feasible
Property, the experimental results showed that, sensor can perceive the generation in crack well and record its extension and closing course, split to structure
Seam monitoring has good repeatability, sensitivity and stability, and when bending section initial diameter is 12mm, range is up to 20mm.
It is practical for different engineering, by the way that the range of the bending section optical fiber flexibly changing sensor of different-diameter and sensitive is arranged
Degree.Compared with existing fibre optical sensor, which has the characteristics that structure is simple, small in size, inexpensive and easy for installation,
It is more suitable for concrete structure crack monitoring.
Claims (5)
1. a kind of fibre optical sensor for concrete structure crack monitoring, which is characterized in that set gradually relatively including nozzle
The first capillary tubing (4) and the second capillary tubing (5), sequentially pass through in the first capillary tubing (4) and the second capillary tubing (5)
Bare fibre (6) after the doubling of both ends, the fibre-optical bending section (1) of bare fibre (6) are located at the first capillary tubing (4) outside, bare fibre
(6) two ends are located at the outside of the second capillary tubing (5), wherein are located at the second capillary tubing (5) internal bare fibre
(6) it is fixed as one with the second capillary tubing (5) inner wall.
2. a kind of fibre optical sensor for concrete structure crack monitoring according to claim 1, which is characterized in that institute
It states and is provided with pedestal (3) on the first capillary tubing (4) and the second capillary tubing (5) tube wall, screw hole (2) are provided on pedestal (3),
First capillary tubing (4) and the second capillary tubing (5) are fixed on measurement by screw hole (2) on pedestal (3) and screw fit
At position.
3. a kind of fibre optical sensor for concrete structure crack monitoring according to claim 1, which is characterized in that institute
Stating the first capillary tubing (4) and the second capillary tubing (5) bore is 1.5~3mm.
4. a kind of fibre optical sensor for concrete structure crack monitoring according to claim 1, which is characterized in that institute
The determinant for stating fibre-optical bending section (1) is bending diameter, and bending diameter range is 5mm~26mm.
5. a kind of fibre optical sensor for concrete structure crack monitoring according to any one of claims 1 to 4, special
Sign is, is located at the second capillary tubing (5) internal bare fibre (6) and the second capillary tubing (5) inner wall passes through epoxide-resin glue
It is adhesively fixed.
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110987946A (en) * | 2019-12-27 | 2020-04-10 | 西安理工大学 | Device and method for improving accuracy of crack sensor by using optical splitter |
| CN111426272A (en) * | 2020-04-21 | 2020-07-17 | 湘潭大学 | Method for measuring internal displacement change of slope model |
| CN112525073A (en) * | 2020-11-19 | 2021-03-19 | 哈尔滨工业大学 | Concrete crack position and width identification method based on Brillouin gain spectrum |
| CN113917108A (en) * | 2021-09-07 | 2022-01-11 | 三峡大学 | Model test device for simulating high and steep slope excavation unloading and displacement monitoring method |
| CN114046735A (en) * | 2021-12-24 | 2022-02-15 | 西北工业大学 | Crack opening displacement measuring device |
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|---|---|---|---|---|
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| CN110987946A (en) * | 2019-12-27 | 2020-04-10 | 西安理工大学 | Device and method for improving accuracy of crack sensor by using optical splitter |
| CN111426272A (en) * | 2020-04-21 | 2020-07-17 | 湘潭大学 | Method for measuring internal displacement change of slope model |
| CN111426272B (en) * | 2020-04-21 | 2021-12-03 | 湘潭大学 | Method for measuring internal displacement change of slope model |
| CN112525073A (en) * | 2020-11-19 | 2021-03-19 | 哈尔滨工业大学 | Concrete crack position and width identification method based on Brillouin gain spectrum |
| CN112525073B (en) * | 2020-11-19 | 2022-06-03 | 哈尔滨工业大学 | Structural crack identification method based on Brillouin gain spectrum characteristic parameters |
| CN113917108A (en) * | 2021-09-07 | 2022-01-11 | 三峡大学 | Model test device for simulating high and steep slope excavation unloading and displacement monitoring method |
| CN113917108B (en) * | 2021-09-07 | 2024-03-12 | 三峡大学 | Model test device for simulating high-steep slope excavation unloading and displacement monitoring method |
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