ASTM_D_7764_-_20.pdf

Designation:D776420Standard Practice forPre-Installation Acceptance Testing of Vibrating WirePiezometers1This standard is issued under the fixed designation D7764;the number immediately following 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.Scope*1.1 This practice describes two acceptance tests for avibrating wire piezometer:a zero test and a down-hole test.Thetwo tests can help a user verify that the piezometer is operatingproperly before it is installed.1.2 This practice offers an organized collection of informa-tion or a series of options and does not recommend a specificcourse of action.This document cannot replace education orexperience and should be used in conjunction with professionaljudgment.Not all aspects of this practice may be applicable inall circumstances.This ASTM standard is not intended torepresent or replace the standard of care by which theadequacy of a given professional service must be judged,norshould this document be applied without consideration of aprojects many unique aspects.The word“standard”in thetitle of this document means only that the document has beenapproved through the ASTM consensus process.1.3 UnitsThe values stated in SI units are to be regardedas standard.No other units of measurement are included in thisstandard.Reporting of test results in units other than SI shallnot be regarded as nonconformance with this standard.1.4 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,health,and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.5 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade(TBT)Committee.2.Referenced Documents2.1 ASTM Standards:2D653 Terminology Relating to Soil,Rock,and ContainedFluidsD3740 Practice for Minimum Requirements for AgenciesEngaged in Testing and/or Inspection of Soil and Rock asUsed in Engineering Design and Construction3.Terminology3.1 Definitions:3.1.1 For definitions of common technical terms in thisstandard,refer to Terminology D653.3.2 Definitions of Terms Specific to This Standard:3.2.1 vibrating wire piezometer,na type of pressure sensorthat is used to monitor pore-water pressure.3.2.1.1 Discussion“Vibrating wire”refers to the mecha-nism by which pressure on the sensors diaphragm is convertedto an electrical signal that is transmitted to a readout device.Atensioned wire connected to the diaphragm is plucked by anelectromagnetic pulse,and the resulting natural frequency ismonitored by the readout.Any change in pressure on thediaphragm changes the tension of the wire and the resultingfrequency.A typical vibrating wire piezometer reports gaugepressure,rather than absolute pressure.In this standard,thewords“vibrating wire piezometer,”“piezometer,”and“sensor”will be used interchangeably.4.Significance and Use4.1 Vibrating wire piezometers are typically not recoverableafter installation.Replacement,which involves drilling a newborehole,is expensive and sometimes impossible.Thus it isimportant to be certain that the sensor is operational before itis installed.1This practice is under the jurisdiction of ASTM Committee D18 on Soil andRock and is the direct responsibility of Subcommittee D18.23 on Field Instrumen-tation.Current edition approved Aug.1,2020.Published August 2020.Originallyapproved in 2012.Last previous edition approved in 2012 as D776412.DOI:10.1520/D7764-20.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.*A Summary of Changes section appears at the end of this standardCopyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade(TBT)Committee.4.2 Lacking sophisticated testing facilities,field testers mustuse equipment that is at hand.But in so doing,field testersshould not expect to achieve the same accuracy and precisionthat manufacturers state on the sensor calibration record.Instead,fieldtestersshouldlookforobviousnon-conformances,as explained in the procedures.4.3 Thi