1、Designation: F3079 14Standard Practice forUse of Distributed Optical Fiber Sensing Systems forMonitoring the Impact of Ground Movements During Tunneland Utility Construction on Existing Underground Utilities1This standard is issued under the fixed designation F3079; the number immediately following
2、the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This practice specific
3、ally addresses the means andmethods for the use of distributed optical fiber sensors formonitoring ground movements during tunnel and utility con-struction and its impact on existing utilities.1.2 This practice applies to the process of selecting suitablematerials, design, installation, data collect
4、ion, data processingand reporting of results.1.3 This practice applies to all utilities that transport water,sewage, oil, gas, chemicals, electric power, communicationsand mass media content.1.4 This practice applies to all tunnels that transport and/orstore water or sewage.1.5 This practice also ap
5、plies to tunnels that carry theutilities in (1.3), water for hydropower, traffic, rail, freight,capsule transport, and those used for storage.1.6 The values stated in inch-pound units are to be regardedas standard. The values given in parentheses are mathematicalconversions to SI units that are prov
6、ided for information onlyand are not considered standard.1.7 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bili
7、ty of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2E177 Practice for Use of the Terms Precision and Bias inASTM Test MethodsE2586 Practice for Calculating and Using Basic Statistics2.2 Other Standards:IEC 61753-1 Fibre Optic Interconnecting Devices and Pas-sive Comp
8、onents Performance StandardPart 1: Generaland Guidance for Performance Standards3IEC 61757-1 Fibre Optic SensorsPart 1: Generic Specifi-cation3COST Action 299 “FIDES” Optical Fibres for New Chal-lenges Facing the Information Society4ITU-T G.652 Characteristics of a Single-mode Optical Fibreand Cable
9、53. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 accuracythe closeness of the measured value to thetrue or the ideal value of the parameter being measured.Accuracy represents the difference between the measuredresult and the true value and is affected by both bias andprecision
10、.3.1.2 attenuationthe decrease in power of a signal, or lightwave, from interaction with the propagation medium. Thedecrease usually occurs as a result of absorption, reflection,diffusion, scattering, deflection, dispersion or resistance.3.1.3 attenuation budget (also called optical power dynamicran
11、ge and link budget)the maximum cumulative one-way ortwo-way power loss between the interrogator and the measure-ment point that allows a measurement with a specified perfor-mance.3.1.4 biasthe difference between the measured result afteraveraging and the true value. The true value can be obtainedeit
12、her by measuring a reference standard maintained by thenational standard organizations or by using a traceable mea-suring instrument.3.1.5 bofdaBrillouin optical frequency domain analysis.1This test method is under the jurisdiction of ASTM Committee F36 onTechnology and Underground Utilities and is
13、the direct responsibility of Subcom-mittee F36.10 on Optical Fiber Systems within Existing Infrastructure.Current edition approved Oct. 1, 2014. Published October 2014. DOI: 10.1520/F3079-14.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serv
14、iceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from International Electrotechnical Commission (IEC), 3, rue deVaremb, P.O. Box 131, CH-1211 Geneva 20, Switzerland, http:/www.iec.ch.4For additional informati
15、on, visit http:/www.cost.eu.5Available from International Telecommunication Union (ITU), Place desNations 1211, Geneva 20, Switzerland, http:/www.itu.int.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States13.1.6 bofdrBrillouin optical fre
16、quency domain reflectom-etry.3.1.7 botdaBrillouin optical time domain analysis.3.1.8 botdrBrillouin optical time domain reflectometry.3.1.9 characteristic frequency and/or wavelength at refer-ence temperature (Brillouin technologies)the wavelengththat characterizes the sensor response at reference t
17、emperatureas monitored by the interrogator. As Brillouin frequency varieswith wavelength of the light source, this also changes thetemperature and strain coefficients for various sensing fibers.Therefore, the characteristic frequency and the wavelength at aspecified reference temperature and at zero
18、 strain are usuallyprovided by the producers.3.1.10 claddingoptical transparent material over the coreof the fiber optic cable, with a refractive index lower than thatof the core, to provide total internal reflectance.3.1.11 connectorcoupling device that permits a signal topass from one optical fibe
19、r to another.3.1.12 connector insertion lossthe power loss due to theinsertion of a connector between two elements.3.1.13 contractorusually, the entity in charge of construc-tion of the new tunnel or other infrastructure that may impactthe utility.3.1.14 corethe primary light-conducting region of an
20、optical fiber. The refractive index of the core is higher than itscladding, the condition necessary for total internal reflection.3.1.15 cross-sensitivitythe unwanted change of measuredresult due to the influence of physical factors other than themeasured parameters.3.1.16 distributed optical fiber
21、sensor system (DOFSS)asystem using optical fiber cable as a sensor, without discreteelements such as wound mandrels or fiber Bragg gratings, thatis sensitive over its entire length to deliver spatially continuousand resolvable data on the desired measured parameters.3.1.17 drifta slow change in time
22、 of the monitoringcharacteristics of the measurement system.3.1.18 durabilitya quality of a manufactured componentof a measurement system or of the entire measurement systemmeasured by how well it withstands a sustained period ofspecified operation.3.1.19 engineerthe licensed professional engineer d
23、esig-nated by the owner/operator of the utility or the tunnel torepresent the owners/operators interests during the groundmovement monitoring process.3.1.20 failure criteria of the sensorthe measurement un-certainty due to overstressing, overheating and other factorsleading to results or data that a
24、re unreliable.3.1.21 gauge length (GL)the length of the fiber thatcontributes to the measured output value of a single channel.3.1.22 life expectancya period of time during which themeasuring system or its components are expected to operateaccording to its specifications for defined conditions.3.1.2
25、3 limiting conditionsthe extreme conditions that ameasuring instrument is required to withstand without damage,needing to switch off or degradation of specified characteristicswhen it is subsequently operated under its rated operatingconditions.3.1.24 linearitythe tolerance to which the transfer re-
26、sponse characteristics of a measurement system (scale factor)approximates a straight line over the sensor range of thesystem. For Brillouin sensors, it means that the range oftemperature or strain should be within the Brillouin frequencywhich is linearly proportional to the strain or temperature. Fo
27、rOptical Frequency-Domain Reflectometry (OFDR) systems itmeans that the wavelength or frequency shift is linearlyproportional to temperature or strain over certain length.3.1.25 link budget (also called optical power dynamic rangeor attenuation budget)the maximum cumulative one-way ortwo-way power l
28、oss between the interrogator and the measure-ment point that allows a measurement with a specified perfor-mance.3.1.26 location accuracythe estimated location of a mea-surement or other system output, such as a detection report,minus the true location of the stimulus that generated themeasurement or
29、 output.3.1.27 measurement rangea set of values of measuredparameters for which the error of a measuring instrument isintended to fall within specified limits.3.1.28 measuring spatial resolutionthe minimum distanceover which the DOFSS is able to detect the value of themeasured parameter, such as str
30、ain or temperature, averagedover this minimum distance, within the specified uncertainty.3.1.29 measuring timethe required time interval needed toobtain a measurement within the specified uncertainty, thespatial resolution, and the system range, including any timerequired for data post-processing.3.
31、1.30 noisethe random variation in the measurementresult unrelated to the measured parameter. It primarily affectsthe precision of measurement.3.1.31 operating temperature range of the measurementunitthe range of temperatures over which, the measurementunit can collect data on the parameters of inter
32、est, withoutlosing its capacity for performance and reliability.3.1.32 operatorthe firm hired by the owner to performoperation and maintenance of the tunnel or utility.3.1.33 optical fiber sensing cablecable formed using oneor more strands of optical fiber to sense physical parametersand/or transmit
33、 data.3.1.34 optical fiber sensorcomposed of one or moreoptical fiber sensing cables and the associated light signalprocessing equipment as pertinent to DOFSS defined in 3.1.16.3.1.35 optical power dynamic range (also called link budgetand attenuation budget)the maximum cumulative one-wayor two-way
34、power loss between the interrogator and themeasurement point that allows measurement with a specifiedperformance.3.1.36 ownerthe person(s) or a governing body chargedwith construction, operation and maintenance of the under-ground utility or tunnel system.F3079 1423.1.37 precisiondescribes how repea
35、table a measurementresult is. Precision is measured by the estimated standarddeviation of a specified series of measurements.3.1.38 Rayleigh cotdrRayleigh coherent optical time do-main reflectometry.3.1.39 repeatabilitythe closeness of the agreement be-tween the results of successive measurements of
36、 the samemeasured parameter carried out under the same conditions ofmeasurement. This means that for every one hundred repeatedstrain or temperature measurements, repeatability is the mea-sure of the highest probability associated with either the strainor the temperature.3.1.40 reportthe official wr
37、itten work product or projectdeliverable that contains a description of the scope of workdone, data collected and presented in various forms, interpre-tation of the data, findings and recommendations for furtheraction.3.1.41 reproducibilitythe closeness of the agreement be-tween the results of measu
38、rements of the same measuredparameter carried out under changed conditions of measure-ment.3.1.42 resolutionthe smallest change in the measuredparameter that can be indicated by the measurement system.Not to be confused with precision. This is often called the“quantization interval” of the measureme
39、nt system.3.1.43 responsivitythe change in the response (outputsignal) of a complete measurement system to the correspond-ing change in the stimulus (input signal).3.1.44 scale factorthe inverse of the ratio of a change inthe stimulus to corresponding measured change.3.1.45 scale factor at reference
40、 conditionsthe ratio of themeasured input parameters engineering units to the outputparameters units.3.1.46 sensor rangethe range between the smallest andthe largest allowable value of the measured parameter.3.1.47 spatial resolutionthe minimum distance betweentwo step transitions of the measured pa
41、rameter in time domainthat can be independently observed with a specified perfor-mance.3.1.48 spatial sampling interval (dx)The spatial distancealong the fiber between two adjacent outputs of the DOFSS.This is usually controlled by the high-rate temporal samplinginterval of the optical detector, dt,
42、 and the speed of light in thefiber, cf, using dx = dt*cf/2. The spatial sampling interval shallbe at least one-half of the spatial resolution.3.1.49 system distance rangethe length of fiber overwhich the measurement can be performed within the statedprecision, or the system can achieve its stated p
43、erformance (forexample, probability of detection, location accuracy.).3.1.50 testerthe person or the entity responsible for car-rying out the evaluation of the impact of tunneling or utilityconstruction.3.1.51 total internal reflectionreflection that occurs in amedium when the incidence angle of a l
44、ight ray striking aboundary of the medium is greater than the critical angle andthe entire energy of the ray is reflected back into the medium.3.1.52 true valuethe result of a measurement that wouldbe obtained by a perfect measurement with no precision or biaserror.3.1.53 updating timethe time inter
45、val between updates ofthe measured value of all channels of the DOFSS. This is thesame as the temporal sampling interval for systems other thanmulti-channel or those that provide data incrementally.3.1.54 warm-up timethe duration from the time power isturned on until the system performs in accordanc
46、e with allspecifications.3.1.55 wavelengththe length of a wave measured fromany point on a wave to the corresponding point on the nextcycle of the wave.3.1.56 wavelength of operationthe range of wavelengthsof optical radiation the sensor uses to provide the required data.NOTE 1Every effort has been
47、made in the above definitions to beconsistent with those defined in Cost Action 299 and IEC 61757-1.4. Summary of Practice4.1 Distributed optical fiber sensing technology has manyadvantages over current methods using discrete “point” sensorsfor monitoring ground movements around underground utili-ti
48、es and tunnels. The advantages include, but are not limited to:4.1.1 Their distributed nature means that there are nomonitoring gaps, as compared to conventional point sensors,provided the distributed optical fiber sensing cable is installedover the whole length, area or volume of interest;4.1.2 Asi
49、ngle optical fiber sensing cable can provide tens ofthousands of continuously distributed measurement points;4.1.3 No electricity used within the optical fiber sensingcable; thus, it is immune to electromagnetic interference anddoes not cause electromagnetic interference (EMI), other thanthat generated by the electro-optical equipmentwhich can beshielded and controlled;4.1.4 They are generally safe in explosive environments;4.1.5 They can be made robust to chemical exposurethrough proper design and materials selecti
