CN205066708U - Inside freeze thawing dilatational strain optical fiber sensor of monitoring concrete structure - Google Patents
Inside freeze thawing dilatational strain optical fiber sensor of monitoring concrete structure Download PDFInfo
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- CN205066708U CN205066708U CN201520840284.5U CN201520840284U CN205066708U CN 205066708 U CN205066708 U CN 205066708U CN 201520840284 U CN201520840284 U CN 201520840284U CN 205066708 U CN205066708 U CN 205066708U
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- 239000004567 concrete Substances 0.000 title claims abstract description 81
- 239000013307 optical fiber Substances 0.000 title claims abstract description 60
- 238000012544 monitoring process Methods 0.000 title claims abstract description 34
- 238000010257 thawing Methods 0.000 title claims abstract description 25
- 239000000835 fiber Substances 0.000 claims abstract description 23
- 230000003287 optical effect Effects 0.000 claims abstract description 21
- 238000004804 winding Methods 0.000 claims abstract description 17
- 238000000034 method Methods 0.000 claims abstract description 13
- 229910000831 Steel Inorganic materials 0.000 claims abstract description 12
- 239000010959 steel Substances 0.000 claims abstract description 12
- 230000001681 protective effect Effects 0.000 claims description 10
- 239000011083 cement mortar Substances 0.000 claims description 7
- 230000008569 process Effects 0.000 claims description 6
- 230000002093 peripheral effect Effects 0.000 claims description 2
- 239000000463 material Substances 0.000 abstract description 5
- 238000005259 measurement Methods 0.000 abstract description 3
- 238000005452 bending Methods 0.000 abstract description 2
- 239000011248 coating agent Substances 0.000 abstract 1
- 238000000576 coating method Methods 0.000 abstract 1
- 239000004570 mortar (masonry) Substances 0.000 abstract 1
- 239000011241 protective layer Substances 0.000 abstract 1
- 238000005516 engineering process Methods 0.000 description 10
- 230000008014 freezing Effects 0.000 description 5
- 238000007710 freezing Methods 0.000 description 5
- 230000000694 effects Effects 0.000 description 4
- 238000012360 testing method Methods 0.000 description 4
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- 230000008859 change Effects 0.000 description 2
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- 239000011148 porous material Substances 0.000 description 2
- 239000011150 reinforced concrete Substances 0.000 description 2
- 239000002689 soil Substances 0.000 description 2
- 230000009471 action Effects 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 239000012141 concentrate Substances 0.000 description 1
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- 238000002474 experimental method Methods 0.000 description 1
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Abstract
The utility model provides an inside freeze thawing dilatational strain optical fiber sensor of monitoring concrete structure, concrete slab, single mode bending resistance optic fibre wound wire circle, temperature compensating fiber grating, steel pipe, coating mortar and optical cable including vertical two terminal circular arc forms. The concrete material match ratio of being surveyed the concrete slab adoption used with quilt survey concrete structure is the same, and the concrete slab circumference deformation that arouses because of freeze -thaw cycle is carried out surperficial by survey concrete slab to the direct longitudinal winding of optic fibre. Can monitor whole measurement station department and begin the concrete follow military service phase, at a plurality of freeze -thaw cycle of experience cycle mechanism to and last protective layer fracture, peel off in -process concrete slab's circumference and warp, realize the accurate monitoring to concrete freeze thawing dilatational strain. Fine durability is had because of optic fibre itself simultaneously, the durability of sensor will be improved. Concrete structure's such as dam, bridge freeze thawing inflation strain monitoring can be applied to to this sensor, have the high accuracy, longe -lived, conveniently characteristics such as lay.
Description
Technical field
The utility model belongs to optical fiber sensing technology and civil structure project security monitoring field, relates to a kind of novel monitoring xoncrete structure inner freeze thawing expansion strain Fibre Optical Sensor.
Background technology
Fibre Optical Sensor has numerous advantage, its electromagnetism interference without drift, good endurance, high resolving power, high precision, volume is little, encapsulating structure is simple, and can carry out growing apart from advantages such as quasi-distributed/distributed Real-Time Monitorings, thus be widely used in monitoring structural health conditions sensing technology, and Fibre Optical Sensor is considered to be hopeful to be integrated in material internal most in intelligent structure, detect the sensing technology of its damage.This technology has been considered to the desirable sensing element for the monitoring of civil engineering structure long-term safety at present.
Concrete structure in the water conservancy project of cold district, harbor work, the engineering such as road and bridge or the freeze-thaw damage of structures under Frozen-thawed cycled effect are the Major Diseases in operational process.In humid conditions, pore can be filled water to concrete, and at low temperatures, in pore, water congeals into ice, volumetric expansion about 9%, thus produces stress at inside concrete.Exceed concrete ultimate strength due to the repeated action of freeze thawing or internal stress thus cause concrete to produce local failure.The Yun Feng power station in northeast, dam builds up and runs less than 10 years, and overfall dam surface concrete freeze-thaw damage area is just up to 10000m
2, account for about 50% of whole overfall dam area, the average frost and melt damage degree of depth of concrete reaches more than 10cm.Therefore Real-Time Monitoring, assessment are carried out to the freeze thawing expansion damage of xoncrete structure, thus the maintenance of scientific guidance structure is very necessary further.
At present, considerably less with report to the correlative study of xoncrete structure real time monitoring, and mainly all concentrate on the material property conceptual phase in laboratory.The research of laboratory internal is mainly carried out fast concrete standard test block according to specification, slow freeze-thawing test, and its parameter mainly measured has dynamic modulus of elasticity and mass loss rate etc.But the test parameters that this kind of experimental study method records with it all effectively cannot be passed judgment on in-service concrete, more can not reach the object of Real-Time Monitoring.
Zhao Xuefeng, the people such as Lv Xingjun propose a kind of optical fiber concrete freeze thawing expansion strain monitoring sensor (CN201320404147.8), this sensor adopts single mode bend insensitive optical fiber to be wrapped on concrete cylindrical, utilizes Optical Fiber Winding coil directly to measure concrete cylindrical because of freeze thawing and cause circumferential deformation.But this sensing adopt that to be wound body be diameter and be the right cylinder of 5cm-8cm, because its volume is little and its shape is cylindrical, be difficult to ensure that itself and monitored xoncrete structure have good compatibility, and its scope that can monitor has significant limitation, and it needs to get core, complex manufacturing technology, economical not, complicated construction technique.
Chen Jixin discloses a kind of optical fiber Fabry-Perot sensor in its " application of optical fiber Fabry-Perot sensor in freezing and frozen soil are monitored " master thesis, the method is that Fibre Optical Sensor is implanted freezing inside, by the change of monitoring Fibre Optical Sensor spectrum, thus find out the frost heave situation of sensor, the freezing detection experiment of Hollow-Core Photonic Crystal Fibers method amber uses Fabry-perot optical fiber as the freezing strain transducer whether occurred of monitoring.But the method is the inside of sensor directly being implanted test specimen, therefore its cavity segment length and cavity segment and the surrounding concrete interface contact state result that all will affect it and monitor, and because of the restriction of its cavity segment length, its result finally recorded is freezing around cavity segment and the frost heave situation of frozen soil, this monitoring result too limitation.Yin Wendu is uncertain in addition, concrete is very possible in frozen-thaw process only there is surface capillary water generation frost heave, and there is not the differential frost heave situation of frost heave in inside concrete, sensor produces larger impact because of its placement location to monitoring result, does not therefore have cogency to concrete Real-Time Monitoring effect.
Utility model content
Technical problem to be solved in the utility model is to provide a kind of Real-Time Monitoring xoncrete structure inner freeze thawing expansion strain Fibre Optical Sensor.This sensor adopts the single mode bending resistance light guide optical fiber being wrapped in concrete slab surface as sensing unit, this sensor can be built in xoncrete structure inner, and its material behavior is consistent with the match ratio of monitored xoncrete structure, there is extraordinary compatibility, defect and infringement can not be caused to structure; And single mode bend insensitive optical fiber used in the utility model has good permanance, thus can in real time to reinforced concrete structure because frost heave causes the circumferential strain of concrete slab to carry out for a long time, stable monitoring, and then realize the real-time assessment to monolithic concrete structure.
The technical solution of the utility model is:
A kind of monitoring xoncrete structure inner freeze thawing expansion strain Fibre Optical Sensor, comprises cement mortar protective course 1, concrete slab 2, temperature compensation optical fiber grating 3, steel pipe 4, optical cable 5 and single mode bend insensitive optical fiber winding around 6; Single mode bend insensitive optical fiber is longitudinally wrapped in the surface of concrete slab 2, and single mode bend insensitive optical fiber coiling length is greater than 3m, determines to be wound around the number of turns, form the single mode bend insensitive optical fiber winding around 6 centered by concrete slab 2 according to actual conditions; Arrange the steel pipe 4 for the protection of temperature compensation optical fiber grating 3 in concrete slab 2, temperature compensation optical fiber grating 3 one end optical fiber is connected with optical cable 5 and causes that concrete slab 2 is outside to be connected with surveying instrument, and the other end of temperature compensation optical fiber grating 3 is placed in steel pipe; The single mode bend insensitive optical fiber winding around 6 that the cement mortar protective course 1 that 2-5mm is thick is placed in centered by concrete slab 2 is peripheral, plays a protective role.
Described single mode bend insensitive optical fiber is longitudinally wound around 20-25 circle on concrete slab 2, in single mode bend insensitive optical fiber winding process, applies to single mode bend insensitive optical fiber the pre-tension stress that strain is 350-900 μ ε, guarantee optical fiber and concrete slab surface conjunction tight;
Described concrete slab is length 20cm, wide 10cm, thickness 3cm and longitudinal two end arc form.
The concrete slab of the utility model employing is identical with the concrete material of detected concrete structure and match ratio, utilizes the circumferential expansion strain that the coil measurement concrete slab being wrapped in concrete slab surface causes because of Frozen-thawed cycled.The monitoring that optical fiber white light Michelson interference sensor technology or optical fiber Brillouin sensing technology realize causing the circumferential expansion of concrete slab to strain existing RC structures because of freeze thawing can be applied.For compensating the strain that single mode bend insensitive optical fiber Yin Wendu causes, the utility model imbeds temperature compensation optical fiber grating in concrete slab inside, and then should changing to accurately that sensor is monitored, realizes the measurement of reinforced concrete structure internal temperature simultaneously.
In the process of practical application, this sensor is directly cast in the inside of xoncrete structure measuring point, leans on into protective seam by sensor circular arc end, circular arc end surface distance protection layer surface 3-5mm, opposite side is directly cast in xoncrete structure inside.When measuring point place concrete is subject to external environment unfreezing, the concrete slab of sensor internal will produce the circumferential deformation because freeze thawing causes, and the optical fiber being thereupon entangled in concrete slab surface will produce distortion, i.e. the strain of fiber optic coils.Based on this displacement transfer by way of, application optical fiber white light Michelson interference sensor technology or optical fiber Brillouin sensing technology can realize measuring point freeze thawing distortion monitoring.
Effect of the present utility model and benefit: the concrete slab that the utility model is wound has identical proportioning with detected concrete structure, utilize single mode bend insensitive optical fiber winding around directly to measure the freeze thawing expansion strain of whole concrete slab.The utility model can to monitoring point place concrete from the military service phase, through several Frozen-thawed cycled period effects, until crack, to peel off, realizes the precise monitoring to concrete freeze thawing expansion strain.And single mode bend insensitive optical fiber has good permanance used by the utility model, this will improve the life-span of sensor greatly.In addition, because this sensor is directly cast in xoncrete structure inside, itself and xoncrete structure have extraordinary globality, and then, the statement xoncrete structure freeze-thaw damage situation that its result of monitoring more can be strong.
Accompanying drawing explanation
Fig. 1 is monitoring inside concrete freeze thawing expansion strain fibre-optic sensor package structural facades schematic diagram.
Fig. 2 is monitoring inside concrete freeze thawing expansion strain fibre-optic sensor package structural plan schematic diagram.
In figure: 1 cement mortar protective course; 2 concrete slabs; 3 temperature compensation optical fiber gratings; 4 steel pipes; 5 optical cables; 6 single mode bend insensitive optical fiber winding arounds.
Specific implementation method
Embodiment of the present utility model is described in detail below in conjunction with technical scheme and accompanying drawing.
Monitoring inside concrete freeze thawing expansion strain Fibre Optical Sensor; its encapsulating structure comprises: cement mortar protective course, single mode bend insensitive optical fiber winding around, temperature compensation optical fiber grating, thickness are 3cm; length is 20cm, and the concrete slab of longitudinal two end arc form, steel pipe and optical cable.
First, according to the match ratio of detected concrete structure, building a length is 20cm, width 10cm, and thickness is 3cm, and the concrete slab of longitudinal two end arc form, also can choose concrete size according to concrete concrete measuring point situation.In the process of building; the steel pipe for the protection of fiber grating is imbedded in advance in concrete slab; and temperature compensation optical fiber grating is put into steel duct; one end optical fiber of fiber grating is connected with optical cable and causes that outer protection is good; prepare to link with surveying instrument, the other end of fiber grating is freely placed in steel duct.The concrete slab of building is placed standard curing room and carries out maintenance.After treating that its maintenance is complete, is polished in concrete slab surface, make it be wound optical fiber position smooth, then single mode bend insensitive optical fiber is wrapped in concrete slab surface with the pre-tension stress of 350-900 μ ε, and to make between the fiber optic coils that is wound closely and come concrete slab surface.Be wound around the number of turns to enclose at 20-25, Optical Fiber Winding length is greater than 3m, can change the wire circle of corresponding winding on this basis as the case may be.After coil winding is complete, with 502 cementing agents, winding optical fiber two ends are fixed on concrete slab surface, two ends optical fiber is drawn.After more than having worked, carry out the channel check checking optical fiber, finally build the cement mortar protective course of one deck 2-5mm on concrete slab surface, complete the encapsulation to sensor, as Fig. 1, shown in 2.
Claims (3)
1. a monitoring xoncrete structure inner freeze thawing expansion strain Fibre Optical Sensor, it is characterized in that, this monitoring xoncrete structure inner freeze thawing expansion strain Fibre Optical Sensor comprises cement mortar protective course, concrete slab, temperature compensation optical fiber grating, steel pipe, optical cable and single mode bend insensitive optical fiber winding around; Single mode bend insensitive optical fiber is longitudinally wrapped in the surface of concrete slab, and single mode bend insensitive optical fiber coiling length is greater than 3m, determines to be wound around the number of turns, form the single mode bend insensitive optical fiber winding around centered by concrete slab according to actual conditions; Arrange the steel pipe for the protection of temperature compensation optical fiber grating in concrete slab, temperature compensation optical fiber grating one end optical fiber is connected with optical cable and causes that concrete slab is outside to be connected with surveying instrument, and the other end of temperature compensation optical fiber grating is placed in steel pipe; The single mode bend insensitive optical fiber winding around that the cement mortar protective course that 2-5mm is thick is placed in centered by concrete slab is peripheral, plays a protective role.
2. monitoring xoncrete structure according to claim 1 inner freeze thawing expansion strain Fibre Optical Sensor, is characterized in that, described single mode bend insensitive optical fiber is longitudinally wound around 20-25 circle on concrete slab; In single mode bend insensitive optical fiber winding process, strain is applied for the pre-tension stress of 350-900 μ ε to single mode bend insensitive optical fiber, guarantee optical fiber and concrete slab surface conjunction tight.
3. monitoring xoncrete structure according to claim 1 and 2 inner freeze thawing expansion strain Fibre Optical Sensor, is characterized in that, described concrete slab is length 20cm, wide 10cm, thickness 3cm and longitudinal two end arc form.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201520840284.5U CN205066708U (en) | 2015-10-27 | 2015-10-27 | Inside freeze thawing dilatational strain optical fiber sensor of monitoring concrete structure |
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| CN201520840284.5U CN205066708U (en) | 2015-10-27 | 2015-10-27 | Inside freeze thawing dilatational strain optical fiber sensor of monitoring concrete structure |
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| CN201520840284.5U Expired - Fee Related CN205066708U (en) | 2015-10-27 | 2015-10-27 | Inside freeze thawing dilatational strain optical fiber sensor of monitoring concrete structure |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106441139A (en) * | 2016-10-31 | 2017-02-22 | 广东核电合营有限公司 | End anchoring device for strain sensing optical fiber sensor for monitoring concrete structure |
| CN106568390A (en) * | 2016-10-31 | 2017-04-19 | 苏州热工研究院有限公司 | Concrete freeze-thaw expansion strain sensor |
| CN106895789A (en) * | 2017-03-24 | 2017-06-27 | 同济大学 | A kind of cement-based material strain gauge preparation method suitable for ultra-low temperature surroundings |
-
2015
- 2015-10-27 CN CN201520840284.5U patent/CN205066708U/en not_active Expired - Fee Related
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106441139A (en) * | 2016-10-31 | 2017-02-22 | 广东核电合营有限公司 | End anchoring device for strain sensing optical fiber sensor for monitoring concrete structure |
| CN106568390A (en) * | 2016-10-31 | 2017-04-19 | 苏州热工研究院有限公司 | Concrete freeze-thaw expansion strain sensor |
| CN106895789A (en) * | 2017-03-24 | 2017-06-27 | 同济大学 | A kind of cement-based material strain gauge preparation method suitable for ultra-low temperature surroundings |
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| C14 | Grant of patent or utility model | ||
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| CF01 | Termination of patent right due to non-payment of annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20160302 Termination date: 20191027 |