1、Designation: D6724/D6724M 16Standard Guide forInstallation of Direct Push Groundwater Monitoring Wells1This standard is issued under the fixed designation D6724/D6724M; the number immediately following the designation indicates theyear of original adoption or, in the case of revision, the year of la
2、st revision. A number in parentheses indicates the year of lastreapproval. A superscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope*1.1 This guide describes various direct push groundwatermonitoring wells and provides guidance on their selection andinstal
3、lation for obtaining representative groundwater samplesand monitoring water table elevations. Direct push wells areused extensively for monitoring groundwater quality in uncon-solidated formations. This guide also includes discussion ofsome groundwater sampling devices which can be permanentlyemplac
4、ed as monitoring wells.1.2 This guide does not address the single event sampling ofgroundwater using direct push water samplers as presented inGuide D6001. The methods in this guide are often used withother tests such as direct push soil sampling (Guide D6282)and the cone penetrometer test (Guide D6
5、067). The guide doesnot address the installation of monitoring wells by rotarydrilling or sonic drilling methods such as those presented inPractice D5092. Techniques for obtaining groundwatersamples from monitoring wells are covered in Guides D4448,D7929, and Practice D6771. Practice D6725 addresses
6、 directpush wells using pre-packed screens.1.3 The installation of direct push groundwater monitoringwells is limited to unconsolidated soils and sediments includ-ing clays, silts, sands, and some gravels and cobbles. Penetra-tion may be limited, or damage may occur to equipment, incertain subsurfac
7、e conditions; some of which are discussed in5.5. Information in this guide is limited to groundwatermonitoring in the saturated zone.1.4 The values stated in either inch-pound units or SI unitspresented in brackets are to be regarded separately as standard.The values stated in each system may not be
8、 exact equivalents;therefore, each system shall be used independently of the other.Combining values from the two systems may result in non-conformance with the standard.1.5 All observed and calculated values shall conform to theguidelines for significant digits and rounding established inPractice D6
9、026, unless superseded by this standard.1.6 This guide offers an organized collection of informationor a series of options and does not recommend a specific courseof action. This document cannot replace education or experi-ence and should be used in conjunction with professionaljudgement. Not all as
10、pects of this guide may be applicable inall circumstances. This ASTM standard is not intended torepresent or replace the standard of care by which the adequacyof a given professional service must be judged, nor should thisdocument be applied without consideration of a projects manyunique aspects. Th
11、e word “Standard” in the title of thisdocument means only that the document has been approvedthrough the ASTM consensus process.1.6.1 This guide does not purport to comprehensively ad-dress all of the methods and issues associated with monitoringwell installation. Users should seek input from qualif
12、iedprofessionals for the selection of proper equipment and meth-ods that would be the most successful for their site conditions.Other methods may be available for monitoring wellinstallation, and qualified professionals should have flexibilityto exercise judgement concerning alternatives not covered
13、 inthis guide. The practice described in this guide is current at thetime of issue; however, new, alternative, and innovative meth-ods may become available prior to revisions. Therefore, usersshould consult with manufacturers or producers prior tospecifying program requirements.1.7 This standard doe
14、s 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 requirements prior to use.2. Referenced Documents2.1 ASTM Sta
15、ndards: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 ConstructionD4448 Guide for Sampling Ground-Water Monitoring Wells1This guide is under the ju
16、risdiction ofASTM Committee D18 on Soil and Rockand is the direct responsibility of Subcommittee D18.21 on Groundwater andVadose Zone Investigations.Current edition approved July 1, 2016. Published July 2016. Originally approvedin 2001. Last previous editon approved in 2010 as D672404(2010). DOI:10.
17、1520/D6724_D6724M-16.2For 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
18、 the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1D4750 Test Method for Determining Subsurface LiquidLevels in a Borehole or Monitoring Well (ObservationWell) (Withdrawn 2010)3D5088 Practice for Decontamination
19、of Field EquipmentUsed at Waste SitesD5092 Practice for Design and Installation of GroundwaterMonitoring WellsD5254 Practice for Minimum Set of Data Elements toIdentify a Ground-Water SiteD5299 Guide for Decommissioning of Groundwater Wells,Vadose Zone Monitoring Devices, Boreholes, and OtherDevices
20、 for Environmental ActivitiesD5434 Guide for Field Logging of Subsurface Explorationsof Soil and RockD5474 Guide for Selection of Data Elements for Groundwa-ter InvestigationsD5521 Guide for Development of Groundwater MonitoringWells in Granular AquifersD5730 Guide for Site Characterization for Envi
21、ronmentalPurposes With Emphasis on Soil, Rock, the Vadose Zoneand Groundwater (Withdrawn 2013)3D5978 Guide for Maintenance and Rehabilitation ofGroundwater Monitoring WellsD6001 Guide for Direct-Push Groundwater Sampling forEnvironmental Site CharacterizationD6026 Practice for Using Significant Digi
22、ts in GeotechnicalDataD6067 Practice for Using the Electronic Piezocone Pen-etrometer Tests for Environmental Site CharacterizationD6282 Guide for Direct Push Soil Sampling for Environ-mental Site CharacterizationsD6286 Guide for Selection of Drilling Methods for Environ-mental Site Characterization
23、D6452 Guide for Purging Methods for Wells Used forGroundwater Quality InvestigationsD6564 Guide for Field Filtration of Groundwater SamplesD6634 Guide for Selection of Purging and Sampling De-vices for Groundwater Monitoring WellsD6725 Practice for Direct Push Installation of PrepackedScreen Monitor
24、ing Wells in Unconsolidated AquifersD6771 Practice for Low-Flow Purging and Sampling forWells and Devices Used for Ground-Water Quality Inves-tigations (Withdrawn 2011)3D6914 Practice for Sonic Drilling for Site Characterizationand the Installation of Subsurface Monitoring DevicesD7242 Practice for
25、Field Pneumatic Slug (InstantaneousChange in Head) Tests to Determine Hydraulic Propertiesof Aquifers with Direct Push Groundwater SamplersD7352 Practice for Direct Push Technology for VolatileContaminant Logging with the Membrane Interface Probe(MIP)D7929 Guide for Selection of Passive Techniques f
26、or Sam-pling Groundwater Monitoring Wells3. Terminology3.1 DefinitionsFor common definitions of terms in thisstandard, refer to Terminology D653.3.2 Definitions of Terms Specific to This Standard:3.2.1 dual tube systems, na system whereby inner andouter tubes are advanced independently or simultaneo
27、usly intothe subsurface strata.3.2.1.1 DiscussionThe outer casing tube is used for bore-hole stabilization. The inner tube for is used sampler recoveryand insertion of other devices. In Practice D6282, direct pushsoil sampling the dual tube system takes soil samples with asampler fixed to the inner
28、rods.4. Summary of Guide4.1 This guide provides information to be used by experi-enced groundwater professionals for exploration of the subsur-face and ambient groundwater conditions.4.2 This guide outlines a variety of field methods forinstalling direct push groundwater monitoring wells. Installa-t
29、ion methods include: (1) soil probing using combinations ofdynamic (percussion or vibratory) driving with, or without,additions of static (constant) force; (2) static force from thesurface using hydraulic penetrometer or drilling equipment;and (3) incremental drilling combined with direct push meth-
30、ods. Methods for installation of annular seals and annulargrouts are also discussed as well as abandonment grouting.4.3 This guide addresses considerations for selection anduse of direct push well systems and installation techniques thatmay be classified into two main categories; exposed screentechn
31、iques and protected screen techniques. In exposed screentechniques, the screened casing may serve as the drive rod, ormay surround a drive rod that is removed following installa-tion. In protected screen techniques, the well may be advancedalong with a protective outer casing, or may be lowered into
32、 adriven casing that is subsequently removed. Alternatively, thescreen, riser, and a retractable shield may be driven simulta-neously and all remain in the ground.4.4 The interval to be tested is determined in advance byprior exploration, or by soil or water sampling during directpush driving. A scr
33、een section, either protected or unprotected,is connected to riser pipes and either driven on the outside of,or placed inside of direct push rods. With some monitoringwell designs, it may be necessary to add sand pack and seals toisolate the screened test zone as the rods are retracted. The topof th
34、e installation is usually completed in a manner consistentwith regulatory requirements. The well can be developed toremove mobile sediments. Water levels can be measured, andwater samples are taken as required in the sampling plan.5. Significance and Use5.1 The direct push ground method is a rapid a
35、nd economi-cal procedure for installing groundwater monitoring wells toobtain representative groundwater samples and location-specific hydrogeologic measurements. Direct push installationsmay offer an advantage over conventional rotary drilled3The last approved version of this historical standard is
36、 referenced onwww.astm.org.D6724/D6724M 162monitoring wells (Practice D5092) for groundwater explora-tions in unconsolidated formations because they reduce distur-bance to the formation, and eliminate or minimize drillcuttings.At facilities where contaminated soils are present, thiscan reduce hazard
37、 exposure for operators, local personnel, andthe environment, and can reduce investigative derived wastes.Additionally, smaller equipment can be used for installation,providing better access to constricted locations.5.2 Direct push monitoring wells are typically smaller indiameter than drilled wells
38、, thereby reducing purge watervolumes, sampling time, and investigative derived wastes.Practice D5092 monitoring wells are used when larger diam-eters and/or sample volumes are required, or at depths or ingeologic formations to where it is difficult to install direct pushwells. Direct push monitorin
39、g wells should be viable formonitoring for many years.5.3 Prior to construction and installation of a direct pushwell or any other type of groundwater well the reader shouldconsult appropriate local agencies regarding regulatory re-quirements for well construction.Aregulatory variance may berequired
40、 for installation of direct push monitoring wells.5.4 To date, published comparison studies between drilledmonitoring wells and direct push monitoring wells have showncomparability (1-10)4. However, selection of direct push moni-toring wells over conventional rotary drilled wells should bebased on s
41、everal criteria, such as site accessibility andpenetrability, stratigraphic structure, depth to groundwater, andaquifer transmissivity.5.5 Typical penetration depths for installation of groundwa-ter monitoring wells with direct push equipment depend onmany variables. Some of the variables are the si
42、ze and type ofthe driving system, diameter of the drive rods and monitoringwell, and the resistance of the earth materials being penetrated.Some direct push systems are capable of installing groundwa-ter monitoring wells to depths in excess of 100 ft 30 m, andlarger direct push equipment can reach d
43、epths of severalhundred feet. However, installation depths of 10 to 50 ft 5 to15 m are most common. Direct push methods cannot be usedto install monitoring wells in consolidated bedrock (forexample, granite, limestone, gneiss), but are intended forinstallation in unconsolidated materials such as cla
44、ys, silts,sands, and some gravels. Additionally, deposits containingsignificant cobbles and boulders (for example, some glacialdeposits), or strongly cemented materials (for example, cali-che) are likely to hinder or prevent penetration to the desiredmonitoring depth.5.6 For direct push methods to p
45、rovide accurate groundwa-ter monitoring results, precautions must be taken to ensure thatcross-contamination by “smearing” or “drag-down” (that is,driving shallow contamination to deeper levels) does not occur,and that hydraulic connections between otherwise isolatedwater bearing strata are not crea
46、ted. Similar precautions asthose applied during conventional rotary drilling operations(Guide D6286) should be followed.5.7 There have been no conclusive comparisons of effec-tiveness of sealing between drilled monitoring wells and directpush monitoring wells. As with drilled monitoring wells,sealin
47、g methods must be carefully applied to be effective.Research on well sealing (11) has shown that bentonite sealsare not effective above the water table and that if usedbentonite grout requires a minimum of 20 % solids.5.8 Selection of direct push monitoring wells versus con-ventional rotary drilled
48、monitoring wells should be based onmany issues. The advantages and disadvantages of the manyavailable types of driving equipment and well systems must beconsidered with regard to the specific site conditions. Specificwell systems and components, as well as direct push drivingequipment, are described
49、 in Section 7.5.9 Advantages:5.9.1 Minimally intrusive and less disturbance of the naturalformation conditions than many conventional drilling tech-niques.5.9.2 Rapid and economical.5.9.3 Smaller equipment with easier access to many loca-tions.5.9.4 Use of shorter screens can eliminate connectionsbetween multiple aquifers providing better vertical definitionof water quality than long well screens. Shorter screens are alsomore effective at identifying contaminated zones in heteroge-neous formation conditions.5.9.5 Generates little or potentially no contaminated drillcuttings.5
