1、Designation: D6725 04 (Reapproved 2010)Standard Practice forDirect Push Installation of Prepacked Screen MonitoringWells in Unconsolidated Aquifers1This standard is issued under the fixed designation D6725; the number immediately following the designation indicates the year oforiginal adoption or, i
2、n 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 is based on recognized methods by whichdirect push monitoring wells
3、may be designed and installed forthe purpose of detecting the presence or absence of a contami-nant, and collecting representative ground water quality data.The design standards and installation procedures herein areapplicable to both detection and assessment monitoring pro-grams for facilities.1.2
4、The recommended monitoring well design, as presentedin this practice, is based on the assumption that the objective ofthe program is to obtain representative ground water informa-tion and water quality samples from aquifers. Monitoring wellsconstructed following this practice should produce relative
5、lyturbidity-free samples for granular aquifer materials rangingfrom gravels to silty sand. Strata having grain sizes smallerthan the recommended design for the smallest diameter filterpack materials should be monitored by alternative monitoringwell designs which are not addressed in this practice.1.
6、3 Direct push procedures are not applicable for monitor-ing well installation under all geologic and soil conditions (forexample, installation in bedrock). Other rotary drilling proce-dures are available for penetration of these consolidatedmaterials for well construction purposes (Guide D5092). Ad-
7、ditionally, under some geologic conditions it may be appropri-ate to install monitoring wells without a filter pack (EPA1991).Guide D6724 may be referred to for additional information onthese and other methods for the direct push installation ofground water monitoring wells.1.4 The values stated in
8、inch-pound units are to be regardedas standard. The values in parentheses are for information only.1.5 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 healt
9、h practices and determine the applica-bility of regulatory limitations prior to use.1.6 This practice offers a set of instructions for performingone or more specific operations. This document cannot replaceeducation or experience and should be used in conjunctionwith professional judgement. Not all
10、aspects of this practicemay be applicable in all circumstances. This ASTM standard isnot intended to represent or replace the standard of care bywhich the adequacy of a given professional service must bejudged, nor should this document be applied without consid-eration of the projects many unique as
11、pects. The word“Standard” in the title of this document means only that thedocument has been approved through the ASTM consensusprocess.2. Referenced Documents2.1 ASTM Standards:2D1452 Practice for Soil Exploration and Sampling byAugerBoringsD1587 Practice for Thin-Walled Tube Sampling of Soils forG
12、eotechnical PurposesD2488 Practice for Description and Identification of Soils(Visual-Manual Procedure)D3694 Practices for Preparation of Sample Containers andfor Preservation of Organic ConstituentsD4043 Guide for Selection of Aquifer Test Method inDetermining Hydraulic Properties by Well Technique
13、sD4044 Test Method for (Field Procedure) for InstantaneousChange in Head (Slug) Tests for Determining HydraulicProperties of AquifersD4104 Test Method (Analytical Procedure) for DeterminingTransmissivity of Nonleaky Confined Aquifers by Over-damped Well Response to Instantaneous Change in Head(Slug
14、Tests)D4448 Guide for Sampling Ground-Water MonitoringWellsD4700 Guide for Soil Sampling from the Vadose ZoneD5088 Practice for Decontamination of Field EquipmentUsed at Waste SitesD5092 Practice for Design and Installation of GroundWaterMonitoring WellsD5314 Guide for Soil Gas Monitoring in the Vad
15、ose Zone1This practice is under the jurisdiction of ASTM Committee D18 on Soil andRock and is the direct responsibility of Subcommittee D18.21 on Ground Water andVadose Zone Investigations.Current edition approved July 1, 2010. Published September 2010. Originallyapproved in 2001. Last previous edit
16、ion approved in 2004 as D672504. DOI:10.1520/D6725-04R10.2For 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.1Cop
17、yright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.D5521 Guide for Development of Ground-Water Monitor-ing Wells in Granular AquifersD5778 Test Method for Electronic Friction Cone and Piezo-cone Penetration Testing of SoilsD5781 Guide for U
18、se of Dual-Wall Reverse-CirculationDrilling for Geoenvironmental Exploration and the Instal-lation of Subsurface Water-Quality Monitoring DevicesD5782 Guide for Use of Direct Air-Rotary Drilling forGeoenvironmental Exploration and the Installation ofSubsurface Water-Quality Monitoring DevicesD5783 G
19、uide for Use of Direct Rotary Drilling with Water-Based Drilling Fluid for Geoenvironmental Explorationand the Installation of Subsurface Water-Quality Monitor-ing DevicesD5784 Guide for Use of Hollow-Stem Augers for Geoen-vironmental Exploration and the Installation of SubsurfaceWater-Quality Monit
20、oring DevicesD5785 Test Method for (Analytical Procedure) for Deter-mining Transmissivity of Confined Nonleaky Aquifers byUnderdamped Well Response to Instantaneous Change inHead (Slug Test)D5786 Practice for (Field Procedure) for Constant Draw-down Tests in Flowing Wells for Determining HydraulicPr
21、operties of Aquifer SystemsD5787 Practice for Monitoring Well ProtectionD5881 Test Method for (Analytical Procedure) DeterminingTransmissivity of Confined Nonleaky Aquifers by Criti-cally Damped Well Response to Instantaneous Change inHead (Slug)D5912 Test Method for (Analytical Procedure) Determini
22、ngHydraulic Conductivity of an Unconfined Aquifer byOverdamped Well Response to Instantaneous Change inHead (Slug)D6001 Guide for Direct-Push Ground Water Sampling forEnvironmental Site CharacterizationD6282 Guide for Direct Push Soil Sampling for Environ-mental Site CharacterizationsD6285 Guide for
23、 Locating Abandoned WellsD6634 Guide for the Selection of Purging and SamplingDevices for Ground-Water Monitoring WellsD6724 Guide for Installation of Direct Push Ground WaterMonitoring WellsD6771 Practice for Low-Flow Purging and Sampling forWells and Devices Used for Ground-Water Quality Inves-tig
24、ations3. Terminology3.1 DefinitionsRefer to Terminology D653 for definitionsof terminology.3.2 Definitions of Terms Specific to This Standard:3.2.1 prepacked screena manufactured well screen that isassembled with a slotted inner casing and an external filtermedia support. The external filter media s
25、upport may beconstructed of a stainless steel wire mesh screen or slotted PVCthat retains filter media in place against the inner screen. Thefilter media is usually composed of graded silica sand.3.2.2 tremie pipe or tubea pipe or tube that is used totransport filter pack materials and/or annular se
26、alant materialsfrom the ground surface into the borehole annulus or betweencasings and casings or riser pipe of a monitoring well.4. Summary of Practice4.1 This practice provides information for installing a pre-packed screen monitoring well using direct push techniques.When constructed following th
27、is Standard Practice the directpush installed monitoring wells can meet most state regulationsand federal guidelines (EPA 1986, 1991, 1992) for wellconstruction (Fig. 1) and protection of the aquifer and groundwater resources.4.2 Initially the outer casing (or probe rod) is advanced todepth using di
28、rect push methods. The monitoring well isconstructed inside the casing with prepacked well screens andriser pipe. The casing is retracted to set the well at the desireddepth in the formation. Bottom up tremie installation of theannular seal and grout is conducted through the outer casing asit is ret
29、racted. This grouting method is required to obtain thehighest integrity well construction. Commonly available typesof above ground or flush mount well protection are installed tophysically protect the well and prevent tampering. The smalldiameter wells may be developed using bailers, peristalicpumps
30、, bladder pumps or an inertial check valve system. Theinertial check valve and tubing system is especially effectivewhen used for development in medium to coarse-grainedaquifers. This development method simultaneously surges andpurges fines from the screen interval. Slug testing of the wellscan be c
31、onducted to determine local aquifer properties andverify that development has been successful. Low flow andother sampling techniques may be used to obtain representativewater quality samples. Clear and accurate documentation of thewell construction is required.5. Significance and Use5.1 This practic
32、e is intended to provide the user withinformation on the appropriate methods and procedures forinstalling prepacked screen monitoring wells by direct pushmethods. The monitoring wells may be used to obtain repre-sentative water quality samples for aqueous phase contami-nants or other analytes of int
33、erest, either organic or inorganic(Kram et al. 2000, McCall 2000, McCall et al. 1997). Themonitoring wells may also be used to obtain information on thepotentiometric surface of the local aquifer and properties of theformation such as hydraulic conductivity or transmissivity.5.2 Use of direct push m
34、ethods to install monitoring wellscan significantly reduce the amount of potentially hazardousdrill cuttings generated during well installation at contaminatedsites. This may significantly reduce cost of an environmentalsite investigation and ground water monitoring program. Mini-mizing generation o
35、f hazardous waste also reduces the expo-sure hazards to site workers, local residents, and the environ-ment.5.3 Direct push methods for monitoring well installation arelimited to use in unconsolidated formations such as alluvial/stream sediments, glacial deposits, and beach type sediments.Direct pus
36、h methods are generally successful at penetratingclays, silts, sands and some gravel. Deposits such as soils withD6725 04 (2010)2thick caliche layers, or glacial tills with large cobbles orboulders may be difficult or impossible to penetrate to thedesired depth. Direct push methods are not designed
37、forpenetration of consolidated bedrock such as limestone, graniteor gneiss.6. Site Characterization and Well Placement6.1 CharacterizationUnderstanding the project goals aswell as the subsurface geology, hydrogeology, and contaminantdistribution at a site is necessary before installation of moni-tor
38、ing wells can be completed successfully. Steps in a sitecharacterization program may include investigating site his-tory, literature search, site reconnaissance, and field investiga-tion and sampling efforts. The field investigation may includecompletion of borings to collect soil and ground water s
39、amplesand to determine the ground water flow direction. Geophysicalmethods may also be applied to obtain an understanding of thesubsurface geology. Several ASTM standards are available foruse in conducting the site characterization and samplingefforts; these include Guide D6001, Guide D6282, Practic
40、eD5088, Standard Test Method D5778, Standard Test MethodD4044, Practice D1452, Test Method D1586, Practice D1587,Practice D2488, Practice D3694, Guide D4448, Guide D4700,Method D4750, and Guide D5314. Other important sources ofinformation include state and local agencies having responsi-bilities for
41、 ground water protection and regulation. A list ofstate geological surveys are included in Guide D6285. Depend-ing on site conditions, when direct push methods are used forsite characterization (for example, D6001 and D6282)itmaybe possible to complete the site characterization and monitor-ing well
42、installation activities in one mobilization. PracticeD5092 provides further details on site characterization neces-sary for successful installation of monitoring wells and devel-opment of a site conceptual model.6.2 Well PlacementThe well location, depth and length ofscreen interval should be based
43、on project requirements,information obtained during the site characterization activitiesand background research. In general at least one well is placedat a depth and location considered to represent undisturbedbackground water quality conditions. The length and depth ofthe screened interval for the
44、background well(s) should reflectthose of the wells installed hydraulically down gradient of thesite. Information obtained during site characterization regard-ing local hydrogeology, water level(s), contaminant distribu-tion, and ground water flow direction should be used todetermine appropriate wel
45、l placement. If multiple aquifersseparated by aquitards are present beneath the site monitoringwells with screened intervals at multiple depths may berequired at each location. The purpose for installation shouldbe considered in selecting the locations of the monitoringwells. Purposes may include de
46、tection monitoring, long termmonitoring, or data collection to determine the presence,NOTE 1This well design is consistent with most state regulatory requirements promulgated prior to development of direct push techniques (afterPractice D5092)FIG. 1 Specifications for Conventional Monitoring Wells I
47、nstalled with Rotary Drilling Methods.D6725 04 (2010)3extent, and concentrations of potential contaminants. Guidanceon selection of well locations, screen lengths and intervals arefound m several references, some of which are: EPA 1986,1991, 1992, 1998, Nielsen 1991, Fetter 1994, and USGS 1997.7. Mo
48、nitoring Well Construction Materials7.1 GeneralThe materials that are used in the construc-tion of a prepacked screen monitoring well should not mea-surably alter the chemistry of the ground water sample(s) to becollected when appropriate sample collection methods areused. Ideally, PVC should not be
49、 used when monitoring forneat organic solvents that are PVC solvents (Parker 1992).While conventional steel materials (for example, carbon steelor galvanized steel) are not suitable for use under most groundwater monitoring conditions stainless steel has been found toperform well in most corrosive environments, particularlyunder oxidizing conditions (EPA 1991). In most cases Type304 stainless steel will perform satisfactorily for many years(Driscoll 1986). Under highly corrosive and reducing condi-tions Type 316 stainless steel will perform better than Type 304stainless ste
