ASTM_D_7764_-_12.pdf

Designation:D776412Standard 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.Scope1.1 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 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.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 and health practices and determine the applica-bility of regulatory limitations prior to use.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 general definitions,see Terminology D653.3.1.2 absolute pressure,na pressure value that includesthe effect of atmospheric pressure.3.1.3 gauge pressure,na pressure value that excludes theeffect of atmospheric pressure.3.1.4 vibrating wire piezometer,na type of pressure sensorthat is used to monitor pore-water pressure.Vibrating wirerefers to the mechanism by which pressure on the sensorsdiaphragm is converted to an electrical signal that is transmit-ted to a readout device.A typical vibrating wire piezometerreports absolute pressure,rather than gauge pressure.In thisstandard,the words“vibrating wire piezometer,”“piezometer,”and“sensor”will be used interchangably.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.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 This standard practice is not meant to restrict the use ofother appropriate acceptance tests and procedures.NOTE1Notwithstanding the statements on precision and bias con-tained in this practice,the precision of this practice is dependent on thecompetence of the personnel performing it and the suitability of theequipment and facilities used.Agencies that meet the criteria of PracticeD3740 are generally considered capable of competent and objectivetesting.Users of this practice are cautioned that compliance with PracticeD3740 does not itself ensure reliable testing.Reliable testing depends onmany factors;Practice D3740 provides a means of evaluating some ofthese factors.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 July 1,2012.Published October 2012.DOI:10.1520/D7764-12.2For 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.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 5.Equipment5.1 A readout in good working condition and compatiblewith the sensor to be tested.Consult manufacturers usermanual to verify compatibility of the readout.5.2 The calibration record for the sensor to be tested.Vibrating wire sensors typically have unique calibrations,so itis important to match the calibration record to the sensor.6.Zero-Reading Test Procedure6.1 This procedure is used to