1、Designation: D 6725 04Standard Practice forDirect Push Installation of Prepacked Screen MonitoringWells in Unconsolidated Aquifers1This standard is issued under the fixed designation D 6725; the number immediately following the designation indicates the year oforiginal adoption or, in the case of re
2、vision, the year of last revision. 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 practice is based on recognized methods by whichdirect push monitoring wells may be designed
3、 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 The recommended
4、 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 relativelyturbidity-fre
5、e 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.1.3 Direct push p
6、rocedures 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 D 5092).Additionally, unde
7、r some geologic conditions it may be appro-priate to install monitoring wells without a filter pack (EPA1991). Guide D 6724 may be referred to for additional infor-mation on these and other methods for the direct pushinstallation of ground water monitoring wells.1.4 The values stated in inch-pound u
8、nits 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 health practices
9、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 aspects of t
10、his 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 aspects. The w
11、ord“Standard” in the title of this document means only that thedocument has been approved through the ASTM consensusprocess.2. Referenced Documents2.1 ASTM Standards:2D 1452 Practice for Soil Investigation and Sampling byAuger BoringsD 1587 Practice for Thin-Walled Tube Sampling of Soilsfor Geotechn
12、ical PurposesD 2488 Practice for Description and Identification of SoilsVisual-Manual ProcedureD 3694 Practice for Preparation of Sample Containers andfor Preservation of Organic ConstituentsD 4043 Guide for Selection of Aquifer-Test Method inDetermining of Hydraulic Properties by Well TechniquesD 4
13、044 Test Method for (Field Procedure) for InstantaneousChange in Head (Slug Tests) for Determining HydraulicProperties of AquifersD 4104 Test Method for (Analytical Procedure) for Deter-mining Transmissivity of Nonleakey confined aquifers byOver-damped Well Response to Instantaneous Change inHead (S
14、lug Test)D 4448 Guide for Sampling Ground Water MonitoringWellsD 4700 Guide for Soil Sampling from the Vadose ZoneD 5088 Practice for Decontamination of Field EquipmentUsed at Nonradioactive Waste SitesD 5092 Practice for Design and Installation of GroundWater Monitoring Wells in Aquifers1This pract
15、ice is under the jurisdiction of ASTM Committee D18 on Soil andRock and is the direct responsibility of Subcommittee D18.21 on Ground Water.Current edition approved July 1, 2004. Published July 2004. Originally approvedin 2001. Last previous edition approved in 2001 as D 672501.2For referenced ASTM
16、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.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohock
17、en, PA 19428-2959, United States.D 5314 Guide for Soil Gas Monitoring in the Vadose ZoneD 5521 Practice for Development of Ground-Water Moni-toring Wells in Granular AquifersD 5778 Test Method for Performing Electronic FrictionCone and Piezocone Penetration Testing of SoilsD 5781 Guide for Use of Du
18、al-Wall Reverse-CirculationDrilling for Geoenvironmental Exploration and the Instal-lation of Subsurface Water-Quality Monitoring DevicesD 5782 Guide for Use of Direct Air-Rotary Drilling forGeoenvironmental Exploration and the Installation ofSubsurface Water-Quality Monitoring DevicesD 5783 Guide f
19、or Use of Direct Rotary Drilling with WaterBased Drilling Fluid for Geoenvironmental Explorationand the Installation of Subsurface Water-Quality Monitor-ing DevicesD 5784 Guide for Use of Hollow-Stem Augers for Geoen-vironmental Exploration and the Installation of SubsurfaceWater-Quality Monitoring
20、DevicesD 5785 Test Method for (Analytical Procedure) for Deter-mining Transmissivity of Confined NonleakeyAquifers byUnderdamped Well Response to Instantaneous Change inHead (Slug Test)D 5786 Practice for (Field Procedure) for Constant Draw-down Tests in Flowing Wells for Determining HydraulicProper
21、ties of Aquifer SystemsD 5787 Practice for Monitoring Well ProtectionD 5881 Test Method for (Analytical Procedure) Determin-ing Transmissivity of Confined Nonleakey Aquifers byCritically Damped Well Response to InstantaneousChange in Head (Slug)D 5912 Test Method for (Analytical Procedure) Determin-
22、ing Hydraulic Conductivity of an Unconfined Aquifer byOverdamped Well Response to Instantaneous Change inHead (Slug)D 6001 Guide for Direct-Push Water Sampling for Geoen-vironmental InvestigationsD 6282 Guide for Direct Push Soil Sampling for Environ-mental Site CharacterizationsD 6285 Guide for Loc
23、ating Abandoned WellsD 6634 Guide for Selection of Purging and SamplingEquipment for Ground Water Monitoring WellsD 6724 Guide for Installation of Direct Push MonitoringWellsD 6771 Practice for Low-Flow Purging and Sampling forWells and Devices Used for Ground-Water Quality Inves-tigations3. Termino
24、logy3.1 DefinitionsRefer toTerminology D 653 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 support may becon
25、structed 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 sealant materialsf
26、rom 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 this Standard Prac
27、tice 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 direct push method
28、s. 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 retracted. This gro
29、uting 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, bladder pumps
30、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 conducted to dete
31、rmine 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 practice is intended to
32、 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 interest, either or
33、ganic 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 methods to instal
34、l 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 of hazardous wast
35、e 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 push methods are ge
36、nerally successful at penetratingclays, silts, sands and some gravel. Deposits such as soils withthick caliche layers, or glacial tills with large cobbles orboulders may be difficult or impossible to penetrate to theD6725042desired depth. Direct push methods are not designed forpenetration of consol
37、idated 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-toring wells can be complet
38、ed 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 samplesand to determine t
39、he 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 D 6001, Guide D 6282, PracticeD 5088, Standard Test
40、 Method D 5778, Standard Test MethodD 4044, Practice D 1452, Test Method D 1586, PracticeD 1587, Practice D 2488, Practice D 3694, Guide D 4448,Guide D 4700, Method D 4750, and Guide D 5314. Otherimportant sources of information include state and localagencies having responsibilities for ground wate
41、r protectionand regulation.Alist of state geological surveys are included inGuide D 6285Depending on site conditions, when direct pushmethods are used for site characterization (for example,D 6001 and D 6282) it may be possible to complete the sitecharacterization and monitoring well installation ac
42、tivities inone mobilization. Practice D 5092 provides further details onsite characterization necessary for successful installation ofmonitoring wells and development of a site conceptual model.6.2 Well PlacementThe well location, depth and length ofscreen interval should be based on project require
43、ments,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 background well(s)
44、 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 well placement. If mu
45、ltiple 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 detection monitoring
46、, long termmonitoring, or data collection to determine the presence,extent, and concentrations of potential contaminants. Guidanceon selection of well locations, screen lengths and intervals areNOTE 1This well design is consistent with most state regulatory requirements promulgated prior to developm
47、ent of direct push techniques (afterPractice D 5092)FIG. 1 Specifications for Conventional Monitoring Wells Installed with Rotary Drilling Methods.D6725043found m several references, some of which are: EPA 1986,1991, 1992, 1998, Nielsen 1991, Fetter 1994, and USGS 1997.7. Monitoring Well Constructio
48、n 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 used when monitoring for
49、neat 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 steel (EPA 1991). The prepacked
