1、Designation: D 7242 06Standard Practice forField Pneumatic Slug (Instantaneous Change in Head) Teststo Determine Hydraulic Properties of Aquifers with DirectPush Ground Water Samplers1This standard is issued under the fixed designation D 7242; the number immediately following the designation indicat
2、es 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 (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This standard practice covers the field meth
3、ods used toconduct an instantaneous change in head (slug) test whenpneumatic pressure is used to initiate the change in headpressure within the well or piezometer. While this practicespecifically addresses use of pneumatic initiation of slug testswith direct push tools these procedures may be applie
4、d to wellsor piezometers installed with rotary drilling methods whenappropriate.1.2 This standard practice is used to obtain the required fielddata for determining hydraulic properties of an aquifer or aspecified vertical interval of an aquifer. Field data obtainedfrom application of this practice a
5、re modeled with appropriateanalytical procedures (Test Methods D 4104, D 5785, D 5881,D 5912, Ref (1)2).1.3 UnitsThe values stated in either SI units or inch-pound units are to be regarded separately as standard. Thevalues stated in each system may not be exact equivalents;therefore, each system sha
6、ll be used independently of the other.Combining values from the two systems may result in non-conformance with the standard.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 appr
7、o-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.1.5 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 profess
8、ional judgment. Not all aspects of this practice maybe applicable in all circumstances. This ASTM standard is notintended to represent or replace the standard of care by whichthe adequacy of a given professional service must be judged,nor should this document be applied without consideration ofa pro
9、jects many unique aspects. The word “standard” in thetitle means that the document has been approved through theASTM consensus process.2. Referenced Documents2.1 ASTM Standards:3D 653 Terminology Relating to Soil, Rock, and ContainedFluidsD 2434 Test Method for Permeability of Granular Soils(Constan
10、t Head)D 3740 Practice for Minimum Requirements for AgenciesEngaged in the Testing and/or Inspection of Soil and Rockas Used in Engineering Design and ConstructionD 4104 Test Method (Analytical Procedure) for Determin-ing Transmissivity of Nonleaky Confined Aquifers byOverdamped Well Response to Ins
11、tantaneous Change inHead (Slug Tests)D 4750 Test Method for Determining Subsurface LiquidLevels in a Borehole or Monitoring Well (ObservationWell)D 5084 Test Methods for Measurement of Hydraulic Con-ductivity of Saturated Porous Materials Using a FlexibleWall PermeameterD 5092 Practice for Design an
12、d Installation of GroundWater Monitoring WellsD 5521 Guide for Development of Ground-Water Monitor-ing Wells in Granular AquifersD 5785 Test Method for (Analytical Procedure) for Deter-mining Transmissivity of Confined Nonleaky Aquifers byUnderdamped Well Response to Instantaneous Change inHead (Slu
13、g Test)D 5856 Test Method for Measurement of Hydraulic Con-ductivity of Porous Material Using a Rigid-Wall,Compaction-Mold PermeameterD 5881 Test Method for (Analytical Procedure) Determin-ing Transmissivity of Confined Nonleaky Aquifers byCritically Damped Well Response to InstantaneousChange in He
14、ad (Slug)1This 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 March 1, 2006. Published March 2006.2The boldface numbers in parentheses refer to the
15、 list of references at the end ofthis standard.3For 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.1Copyright AST
16、M International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.D 5912 Test Method for (Analytical Procedure) Determin-ing Hydraulic Conductivity of an Unconfined Aquifer byOverdamped Well Response to Instantaneous Change inHead (Slug)D 6001 Guide for Direct-Push
17、 Ground Water Sampling forEnvironmental Site CharacterizationD 6282 Guide for Direct Push Soil Sampling for Environ-mental Site CharacterizationsD 6724 Guide for Installation of Direct Push Ground WaterMonitoring WellsD 6725 Practice for Direct Push Installation of PrepackedScreen Monitoring Wells i
18、n Unconsolidated Aquifers3. Terminology3.1 Terminology used within this practice is in accordancewith Terminology D 653 with the addition of the following:3.2 Definitions:3.2.1 direct-push (DP) samplingsampling devices that aredirectly inserted into the soil without drilling or boreholeexcavation. D
19、 60013.2.2 two-tube systema system whereby inner and outertubes are advanced simultaneously into the subsurface strata tocollect a soil sample, sometimes referred to as dual-tube. Theouter tube is used for borehole stabilization. The inner tube forsampler insertion and recovery. D 62823.2.3 single-t
20、ube systema system whereby singleextension/drive rods with samplers attached are advanced intothe subsurface strata to collect a soil sample. D 62823.2.4 slug testa single well test to measure aquifer prop-erties such as transmissivity and hydraulic conductivity. A slugtest is conducted by inducing
21、a near instantaneous change inthe static water level in a well and observing the recovery ofthe water level to static condition over time. Also called aninstantaneous change in head test.4. Summary of Practice4.1 This practice describes the field procedures used toconduct an instantaneous change in
22、head (slug) test in a directpush (DP) installed ground water sampling device or monitor-ing well using air pressure to cause a sudden change in thewater level. A pneumatic manifold is installed on a developedwell or DP installed device to control the pressure in thewellhead. Positive pressure or vac
23、uum may be applied with thepneumatic manifold to induce a rising head test or falling headtest, respectively. The changing water level in the well ismonitored with a transducer and data acquisition device andthe data is saved for curve fitting and analysis.4.2 Appropriate well design and constructio
24、n is necessary toobtain representative slug test results. Furthermore, withoutadequate development (Practice D 6725, Guide D 5521, Refs(1, 2) of the well or ground water sampling device slug testsmay yield biased data. Field quality control may be monitoredby conducting replicate tests after develop
25、ment and visuallycomparing the replicate data sets.4.3 Aquifer response data obtained from the pneumatic slugtests are modeled with the appropriate analysis method (TestMethods D 4104, D 5785, D 5881, D 5912, Refs (1, 3)tocalculate the transmissivity and/or hydraulic conductivity ofthe screened form
26、ation.5. Significance and Use5.1 Combining slug test methods with the use of direct pushinstalled ground water sampling devices provides a time andcost-effective method that was previously not available forevaluating spatial variations of hydraulic conductivity (K) inunconsolidated aquifers. Current
27、 research (Ref (4) has foundthat small (decimeter) scale variations in hydraulic conductiv-ity may have significant influence on solute transport andtherefore design of ground water remediation systems. Otherinvestigators (Ref (5) report that spatial variation in K isbelieved to be the main source o
28、f uncertainty in the predictionof contaminant transport in aquifers. They found that increas-ing the data density for K in model input noticeably reducedthe uncertainty of model prediction. Because of increasedefficiency and reduced costs, the combination of slug testmethods with DP ground water sam
29、pling devices makes itpossible to obtain the additional information required to reduceuncertainty in contaminant transport models and improveremedial action design.5.2 The data obtained from application of this practice maybe modeled with the appropriate analytical method to provideinformation on th
30、e transmissivity and hydraulic conductivity ofthe screened formation in a timely and cost effective manner.5.3 The appropriate analytical method selected for analysisof the data will depend on several factors, including, but notlimited to, the aquifer type (confined, unconfined, leaky) wellconstruct
31、ion parameters (partially or fully penetrating), and thetype of aquifer response observed during the slug test (over-damped or underdamped). Some of the appropriate methodsmay include Test Methods D 4104, D 5785, D 5881 andD 5912. A thorough review of many slug test models andanalytical methods is p
32、rovided in Ref (1).5.4 Slug tests may be conducted in materials of lowerhydraulic conductivity than are suitable for pumping tests. Slugtests may be used to obtain estimates of K for aquitardsconsisting primarily of silts and clays. Special field proceduresmay be required.5.5 The pneumatic slug test
33、 provides some advantages whencompared to pumping tests or slug tests conducted by othermethods.5.5.1 Some of the advantages relative to pump tests include:5.5.1.1 No water added to or removed from the well. Animportant consideration when water quality must not be alteredfor purposes of environmenta
34、l sampling.5.5.1.2 Large volumes of water not removed from the wellas during a pumping test. An important consideration if thegroundwater is contaminated and will require disposal as aregulated waste.5.5.1.3 Slug tests usually require only a fraction of the timeneeded to complete a pump test.5.5.1.4
35、 No large diameter pumping well or down well pumprequired.5.5.1.5 Slug tests provide information on K for the forma-tion in the vicinity of the well.5.5.2 Some advantages relative to slug tests using water ora mechanical slug include:5.5.2.1 No water added to or removed from the well or DPsampler to
36、 conduct the test. Generally does not change waterD7242062quality for sampling. Use of vacuum to induce a falling headtest could result in loss of volatiles from water in the wellcolumn. Additional purging may be required before samplingfor volatile contaminants.5.5.2.2 Pneumatic initiation of the s
37、lug test provides clean,high quality data with minimal noise, especially important inhigh hydraulic conductivity formations and small diameterwells.5.5.2.3 In small diameter DP tools, inserting a mechanicalslug or adding water may be difficult or even preclude accuratemeasurement of changing water l
38、evels.5.5.3 Some disadvantages of slug tests as compared topumping tests include:5.5.3.1 Slug tests provide information on K for the forma-tion only in the vicinity of the well, not a large scale averagevalue as obtained from a pumping test.5.5.3.2 Most slug test analytical methods can provide infor
39、-mation only on aquifer transmissivity and hydraulic conduc-tivity. Pumping test analysis can provide additional informa-tion on aquifer parameters such as specific storage, etc.5.5.4 Some disadvantages of the pneumatic slug test relativeto slug tests using water or a mechanical slug include:5.5.4.1
40、 Airtight seals needed on the well casing or driverods.5.5.4.2 The screen must remain below the water levelthroughout the slug test. Wells screened across the water tablecannot be slug tested with the pneumatic method.5.5.4.3 Pressure transducers and electronic acquisitionmethods usually required fo
41、r pneumatic slug testing. Notalways needed for manual methods.5.5.4.4 Equilibration of water level after pressure (orvacuum) applied to the wellhead increases time required tocomplete the slug test, especially important in low-K forma-tions.5.6 Direct push methods provide some advantages as com-pare
42、d to conventional drilling methods for the installation ofwells and temporary groundwater monitoring devices to beused for slug testing. Some of the advantages include:5.6.1 DP methods minimize generation of soil cuttingsreducing waste handling and disposal costs at contaminatedsites during the inst
43、allation of permanent wells (Guide D 6724,Practice D 6725) and temporary groundwater monitoring de-vices (Guide D 6001).5.6.2 Several types of temporary groundwater monitoringdevices may be installed by DP methods (Guide D 6001).These tools may be installed at various depths and variouslocations for
44、 slug testing and groundwater sampling in uncon-solidated materials. Most of these tools are extracted fordecontamination and multiple re-use. Minimizes the need forpermanent well installations.5.6.3 Short screens may be used to slug test discrete depthintervals to document vertical and lateral vari
45、ations of K withinan aquifer in a cost and time effective manner.5.6.4 Equipment required to install DP wells and temporarygroundwater samplers are often smaller and more mobile thanconventional rotary drilling equipment. This can make siteaccess easier and more rapid.5.6.5 Other direct push screeni
46、ng and sampling methods, forexample Guide D 6282 on soil sampling, can be used to detecttest zones in advance of slug testing, which helps withknowledge of test location.5.6.6 Direct push tests are minimally intrusive.5.6.7 Direct push tests are generally more rapid and lessexpensive than other dril
47、ling methods.5.7 Some disadvantages of DP methods as compared toconventional rotary drilling include:5.7.1 DP methods generally provide a smaller diameter borehole than traditional rotary drilling. This may limit the size ofequipment than can be placed down hole.5.7.2 Direct push tools are designed
48、to penetrate unconsoli-dated materials only. Other rotary drilling methods will berequired to penetrate consolidated rock.5.7.3 Some subsurface conditions my limit the depth ofpenetration of DP methods and tools. Some examples includethick caliche layers, cobbles or boulders, or very densematerials,
49、 such as high density glacial tills.NOTE 1The quality of the result produced by this standard isdependent on the competence of the personnel performing it, and thesuitability of the equipment and facilities used. Agencies that meet thecriteria of Practice D 3740 are generally considered capable of competentand objective testing/sampling/inspection/etc. Users of this standard arecautioned that compliance with Practice D 3740 does not in itself assurereliable results. Reliable results depend on many factors; Practice D 3740provides a means of evaluating some of those factors. P
