1、Designation: D 6724 04Standard Guide forInstallation of Direct Push Ground Water Monitoring Wells1This standard is issued under the fixed designation D 6724; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision
2、. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This guide describes various direct push ground watermonitoring wells and provides guidance on their selection andinstallation for
3、 obtaining representative ground water samplesand monitoring water table elevations. Direct push wells areused extensively for monitoring ground water quality inunconsolidated formations. This guide also includes discussionof some groundwater sampling devices which can be perma-nently emplaced as mo
4、nitoring wells.1.2 This guide does not address the single event sampling ofground water using direct push water samplers as presented inGuide D 6001. The methods in this guide are often used withother tests such as direct push soil sampling (Guide D 6282)and the cone penetrometer test (Guide D 6067)
5、. The presentguide does not address the installation of monitoring wells byrotary drilling methods such as those presented in PracticeD 5092. Techniques for obtaining ground water samples frommonitoring wells are covered in Guide D 4448.1.3 The installation of direct push ground water monitoringwell
6、s 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 subsurface conditions; some of which are discussed in5.5. Information in this guide is limited to ground watermoni
7、toring in the saturated zone.1.4 This guide does not purport to comprehensively addressall of the methods and issues associated with monitoring wellinstallation. Users should seek input from qualified profession-als for the selection of proper equipment and methods thatwould be the most successful f
8、or their site conditions. Othermethods may be available for monitoring well installation, andqualified professionals should have flexibility to exercisejudgement concerning alternatives not covered in this guide.The practice described in this guide is current at the time ofissue; however, new, alter
9、native, and innovative methods maybecome available prior to revisions. Therefore, users shouldconsult with manufacturers or producers prior to specifyingprogram requirements.1.5 This guide offers an organized collection of informationor a series of options and does not recommend a specific courseof
10、action. This document cannot replace education or experi-ence and should be used in conjunction with professionaljudgement. Not all aspects 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 gi
11、ven professional service must be judged, nor should thisdocument be applied without consideration of a projects manyunique aspects. The word “Standard” in the title of thisdocument means only that the document has been approvedthrough the ASTM consensus process.1.6 This standard does not purport to
12、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 Standards:2D 653 Ter
13、minology Relating to Soil, Rock, and ContainedFluidsD 4448 Guide for Sampling Ground Water MonitoringWellsD 4750 Test Method for Determining Subsurface LiquidLevels in a Borehole or Monitoring Well (ObservationWell)D 5088 Practice for Decontamination of Field EquipmentUsed at Non-Radioactive Waste S
14、itesD 5092 Practice for Design and Installation of GroundWater Monitoring Wells in AquifersD 5254 Practice for Minimum Set of Data ElementsD 5299 Guide for Decommissioning Monitoring Wells, Va-dose Zone Monitoring Devices, Boreholes, and OtherDevices for Environmental ActivitiesD 5434 Guide for Fiel
15、d Logging of Subsurface Explora-tions of Soil and RockD 5474 Guide for Selection of Data Elements for GroundWater Investigation1This guide is under the jurisdiction ofASTM Committee D18 on Soil and Rockand is the direct responsibility of Subcommittee D18.21 on Ground Water.Current edition approved J
16、uly 1, 2004. Published July 2004. Originally approvedin 2001. Last previous editon approved in 2001 as D 672401.2For 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
17、standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.D 5521 Guide for Development of Ground Water Monitor-ing Wells in Granular AquifersD 5730 Guide for Site Characterization for Environm
18、entalPurposes with Emphasis on Soil, Rock, the Vadose Zone,and Ground WaterD 6001 Guide for Direct Push Water Sampling for Geoen-vironmental InvestigationsD 6067 Guide for Electronic Cone Penetrometer Testing forEnvironmental Site CharacterizationD 6282 Guide for Direct Push Soil Sampling for Enviro
19、n-mental Site CharacterizationD 6286 Guide for Selection of Drilling Methods for Envi-ronmental Site CharacterizationD 6452 Guide for Purging Methods for Wells Used forGroundwater Quality InvestigationsD 6564 Guide for Field Filtration of Ground Water SamplesD 6634 Guide for the Selection of Purging
20、 and SamplingDevices for Ground Water Sampling WellsD 6771 Practice for Low-Flow Purging and Sampling forWells and Devices Used for Ground-Water Quality Inves-tigations3. Terminology3.1 Terminology used within this standard is in accordancewith D 653.4. Summary of Guide4.1 This guide provides inform
21、ation to be used by experi-enced ground water professionals for investigation of thesubsurface and ambient ground water conditions.4.2 This guide outlines a variety of field methods forinstalling direct push ground water monitoring wells. Installa-tion methods include: (1) soil probing using combina
22、tions 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-ods. Methods for installation of annular seals and
23、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 screentechniques and protected screen techniques. In exposed s
24、creentechniques, 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 adriven casing that is subsequently removed. Alter
25、natively, 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 investigation, or by soil or water sampling during directpush driving. A screen section, either protected or unprotected,is c
26、onnected 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 the installation is usually completed in a manner c
27、onsistentwith 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 and economi-cal procedure for installing ground wa
28、ter monitoring wells toobtain representative ground water samples and location-specific hydrogeologic measurements. Direct push installationsmay offer an advantage over conventional rotary drilledmonitoring wells (Practice D 5092) for ground water investi-gations in unconsolidated formations because
29、 they reducedisturbance to the formation, and eliminate or minimize drillcuttings.At facilities where contaminated soils are present, thiscan reduce hazard exposure for operators, local personnel, andthe environment, and can reduce investigative derived wastes.Additionally, smaller equipment can be
30、used for installation,providing better access to constricted locations.5.2 Direct push monitoring wells generally do not extend todepths attainable by drilling. They are also typically smaller indiameter than drilled wells, thereby reducing purge watervolumes, sampling time, and investigative derive
31、d wastes.Practice D 5092 monitoring wells are used when larger diam-eters and/or sample volumes are required, or at depths to whichit is difficult to install direct push wells. Direct push monitoringwells should be viable for monitoring for many years.5.3 Prior to construction and installation of a
32、direct pushwell or any other type of ground water well the reader shouldconsult appropriate local and state agencies regarding regula-tory requirements for well construction in the state. A regula-tory variance may be required for installation of direct pushmonitoring wells in some states.5.4 To dat
33、e, published comparison studies between drilledmonitoring wells and direct push monitoring wells have showncomparability (1, 2, 3, 4, 5). However, selection of direct pushmonitoring wells over conventional rotary drilled wells shouldbe based on several criteria, such as site accessibility andpenetra
34、bility, stratigraphic structure, depth to groundwater, andaquifer transmissivity.5.5 Typical penetration depths for installation of groundwater monitoring wells with direct push equipment depend onmany variables. Some of the variables are the size and type ofthe driving system, diameter of the drive
35、 rods and monitoringwell, and the resistance of the earth materials being penetrated.Some direct push systems are capable of installing groundwater monitoring wells to depths in excess of 100 feet, andlarger direct push equipment, such as the vibratory sonic typedrill (Guide D 6286) are capable of r
36、eaching much greaterdepths, sometimes in excess of 400 ft. However, installationdepths of 10 to 50 feet are most common. Direct push methodscannot be used to install monitoring wells in consolidatedbedrock (for example, granite, limestone, gneiss), but areintended for installation in unconsolidated
37、materials such asclays, silts, sands, and some gravels. Additionally, depositscontaining significant cobbles and boulders (for example, someglacial deposits), or strongly cemented materials (for example,caliche) are likely to hinder or prevent penetration to thedesired monitoring depth.5.6 For direc
38、t push methods to provide accurate groundwater monitoring results, precautions must be taken to ensureD6724042that cross-contamination by “smearing” or “drag-down” (thatis, driving shallow contamination to deeper levels) does notoccur, and that hydraulic connections between otherwise iso-lated water
39、 bearing strata are not created. Similar precautionsas those applied during conventional rotary drilling operations(Guide D 6286) 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 dr
40、illed monitoring wells,sealing methods must be carefully applied to be effective.5.8 Selection of direct push monitoring wells versus con-ventional rotary drilled monitoring wells should be based onmany issues. The advantages and disadvantages of the manyavailable types of driving equipment and well
41、 systems must beconsidered with regard to the specific site conditions. Specificwell systems and components, as well as direct push drivingequipment, are described in Section 7.5.9 Advantages:5.9.1 Minimally intrusive and less disturbance of the naturalformation conditions than many conventional dri
42、lling 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.5.9.5 Generates little or potentially
43、 no contaminated drillcuttings.5.9.6 Less labor intensive than most conventional drillingtechniques.5.10 Disadvantages:5.10.1 Cannot be used to install monitoring devices inconsolidated bedrock and deposits containing significantcobbles and boulders.5.10.2 Small diameter risers and screens limit the
44、 selectionof useable down-hole equipment for purging and sampling.5.10.3 Difficulty installing sand pack in small annular spaceif gravity installation of sand pack is used.5.10.4 Difficulty installing grout in same annular spaceunless appropriately designed equipment is used.6. Pre-Installation Cons
45、iderations6.1 Site CharacterizationSuccessful installation of directpush ground water monitoring wells must be preceded byappropriate site characterization activities. These activitiesmay include reconnaissance, research, conceptual model de-velopment, exploratory field investigations, and confirmat
46、ionand re-evaluation of any existing flow models.6.2 For the installation to be successful, it is imperative thatthe target aquifer be located accurately. As with any wellinstallation, the geologic conditions must be understood andthe stratigraphy must be known. Although direct push wellscan monitor
47、 thinner aquifers, with more precision, they may beineffective is incorrectly placed. In thicker aquifers, and whenseeking dense non-aqueous phase liquids, screens may need tobe located in the bottom of the water-bearing stratum. Wellsplaced without determination of nearby geologic conditionscan be
48、ineffective and possibly dangerous. Geologic investiga-tions should look for perched aquifers and use installationmethods which will avoid any crosscontamination of the unit.6.3 Environmental site characterization approaches are de-scribed in Guide D 5730. Proper site characterization formonitoring
49、well placement is reviewed in Practice D 5092 onMonitoring Well Design.6.3.1 Characterization ToolsIn geologic settings ame-nable to the use of direct push ground water monitoring wells,other direct push methods and tools can likely also be used toeffectively characterize the site. For example, the Cone Pen-etrometer Test (CPT) (Guide D 6067) is an effective tool formapping stratigraphy and locating target layers. Other sensors,such as electrical conductivity and optical detectors have beenplaced on CPT and other direct push systems. Direct push soilsampling (Guide D 6282) and water
