1、Designation: D5521/D5521M 13D5521/D5521M 18Standard Guide forDevelopment of Groundwater Monitoring Wells in GranularAquifers1This standard is issued under the fixed designation D5521/D5521M; the number immediately following the designation indicates theyear of original adoption or, in the case of re
2、vision, the year of last 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 covers the development of screened wells installed for the purpose of obtaining repres
3、entative groundwaterinformation and water quality samples from granular aquifers, though the methods described herein could also be applied to wellsused for other purposes. Other well-development methods that are used exclusively in open-borehole bedrock wells are notdescribed in this guide.1.2 The
4、applications and limitations of the methods described in this guide are based on the assumption that the primaryobjective of the monitoring wells to which the methods are applied is to obtain representative water quality samples from aquifers.Screened monitoring wells developed using the methods des
5、cribed in this guide should yield relatively sediment-free samples fromgranular aquifer materials, ranging from gravels to silty sands. While many monitoring wells are considered “small-diameter”wells (that is, less than 10 cm 4 in. inside diameter), some of the techniques described in this guide wi
6、ll be more easily appliedto large-diameter wells (that is, 10 cm 4 in. or greater inside diameter).1.3 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in eachsystem may not be exact equivalents; therefore, each system shall be use
7、d independently of the other. Combining values from thetwo systems may result in non-conformance with the standard.1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate
8、safety safety, health, and healthenvironmental practices and determine theapplicability of regulatory limitations prior to use.1.5 This guide offers an organized collection of information or a series of options and does not recommend a specific courseof action. This document cannot replace education
9、 or experience and should be used in conjunction with professional judgment.Not all aspects of this guide may be applicable in all circumstances. This ASTM standard is not intended to represent or replacethe standard of care by which the adequacy of a given professional service must needs to be judg
10、ed, nor should this document beapplied without consideration of a projects many unique aspects. The word “Standard” in the title of this document means onlythat the document has been approved through the ASTM consensus process.1.6 This international standard was developed in accordance with internat
11、ionally recognized principles on standardizationestablished in the Decision on Principles for the Development of International Standards, Guides and Recommendations issuedby the World Trade Organization Technical Barriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2D653 Termi
12、nology Relating to Soil, Rock, and Contained FluidsD3740 Practice for Minimum Requirements for Agencies Engaged in Testing and/or Inspection of Soil and Rock as Used inEngineering Design and ConstructionD5088 Practice for Decontamination of Field Equipment Used at Waste SitesD5092 Practice for Desig
13、n and Installation of Groundwater Monitoring Wells1 This guide is under the jurisdiction of ASTM Committee D18 on Soil and Rock and is the direct responsibility of Subcommittee D18.21 on Groundwater and VadoseZone Investigations.Current edition approved Aug. 1, 2013June 1, 2018. Published September
14、2013July 2018. Originally approved in 1994. Last previous edition approved in 20052013 asD5521 05.13. DOI: 10.1520/D5521_D5521M-13.10.1520/D5521_D5521M-18.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM
15、Standardsvolume information, refer to the standards Document Summary page on the ASTM website.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically poss
16、ible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.*A Summary of Changes section appears at the end of this standardCop
17、yright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States13. Terminology3.1 Definitions:3.1.1 For definitions of common terminology terms used within this guide, refer to Terminology D653.3.1 Definitions of Terms Specific to This Standard:Definiti
18、ons:3.2.1 air entrapmenttrapping of air or other gas in pore spaces of the formation or filter pack during development withcompressed air.3.1.1 For definitions of common terminology terms used within this standard, refer to Terminology D653.3.2.2 air lift pumpa device consisting of two pipes, with o
19、ne (the air line) inside the other (the eductor pipe), used to withdrawwater from a well. The lower ends of the pipes are submerged, and compressed air is delivered through the inner pipe to form amixture of air and water. This mixture rises in the outer pipe to the surface because the specific grav
20、ity of this mixture is less thanthat of the water column.3.2.3 air linea small vertical air pipe used in air-lift pumping. It usually extends from the ground surface to near thesubmerged lower end of the eductor pipe. The length of the air line below the static water level is used in calculating the
21、 airpressure required to start air-lift pumping.3.1.2 annular sealseal, nin groundwater, material used to provide a seal between the borehole and the casing of a well. Theannular seal should have a hydraulic conductivity less than that of the surrounding geologic materials and materials, be resistan
22、tto chemical or physical deterioration.3.1.3 backwashingbackwashing, nin groundwater, the reversal of water flow caused by the addition of water to a well thatis designed to loosen bridges and or break sediment bridges within the filter pack and well screen and facilitate the removal offine-grained
23、materialssediment from the formation surrounding the borehole.3.1.4 bailing (development)(development), nin groundwater, a development technique using a bailer which is raised andlowered in the well to create a strong inward and outward movement of water from the formation to break sand bridges and
24、toremove fine materialswell to the formation and vice versa to loosen or break sediment bridges within the filter pack and well screenand to remove fine-grained sediment from the well.3.1.4.1 DiscussionIn unconsolidated formations, casing is usually driven as drilling proceeds to prevent collapse of
25、 non-cohesive materials (that is,sand) into the borehole.3.2.7 cable tool drillinga drilling technique in which a drill bit attached to the bottom of a weighted drill stem is raised anddropped to crush and grind formation materials. In unconsolidated formations, casing is usually driven as drilling
26、proceeds toprevent collapse of noncohesive materials into the borehole.3.2.8 eductor pipethe vertical discharge pipe used in air-lift pumping, submerged at least one third but usually two thirds ofits length below the pumping water level in the well.3.1.5 filter-packed wellwell, nin groundwater, a w
27、ell in which the natural formation where the in situ geologic materialsadjacent to the well screen has been replaced by a an engineered or processed filter pack material.3.1.6 formation damagedamage, nin groundwater, disturbance or reduction of formation hydraulic conductivity in situaquifer hydroge
28、ologic parameters at the borehole wall caused by the drilling process. process, the well installation process, ordestructive, subsurface geoengineering/geotechnical testing. May consist of sediment compaction, clay smearing, clogging ofpores with drilling mud filtrate, or other drilling-relateddrill
29、ing/testing-related damage.3.2.11 hydraulic jettinga well-development method that employs a jetting tool with nozzles and a high-pressure pump to forcewater outwardly through the well screen, the filter pack, and sometimes into the adjacent geologic unit, for the purpose ofdislodging fine sediment a
30、nd correcting formation damage done during drilling.3.2.12 indicator parameterschemical parameters, including pH, specific conductance, temperature and dissolved oxygencontent, which are used to determine when formation water is entering a monitoring well.3.2.13 jettingsee hydraulic jetting.3.2.14 n
31、aturally developed wella well in which the formation materials collapse around the well screen, and fine formationmaterials are removed using standard development techniques.3.1.7 overpumpingoverpumping, nin groundwater, a well-development well development technique that involves pumpingthe well at
32、a rate that exceeds the design capacity of the well.3.1.8 rawhidingin groundwater, starting and stopping a pump intermittently to produce rapid changes in the pressure head inthe well.D5521/D5521M 1823.1.9 sandlockingrefers to the accumulation of sand and other sediment on development tools while th
33、ey are working in thewell screen, resulting in the tools becoming lodged in the screen. Also refers to the accumulation of sand and other sediment inthe impeller section of a submersible pump, resulting in the impellers binding.3.1.9.1 DiscussionThis refers to the accumulation of sand and other sedi
34、ment in the impeller section of a submersible pump, resulting in the impellersbinding.3.2.18 sloughingcaving of formation materials into an unstabilized open borehole.3.1.10 spuddingspudding, nin drilling, the operation, in cable-tool drilling, of drilling a collar hole and advancing a casingthrough
35、 overburden. Also a general term in rotary or diamond core drilling applied to drilling through overburden.3.1.11 sumpwell sump, nin groundwater, a blank extension of easing beneath the well screen that provides a space forfine-grain sediment broughtintroduced into the well during development or gro
36、undwater sampling to accumulate.3.1.12 surge blockblock, nin groundwater, a plunger-like tool consisting of disks of flexible material (for example,(that is,neoprene) sandwiched between rigid (for example,(that is, metal) disks that may be solid or valved, and that is used in welldevelopment. See su
37、rging.3.1.13 surgingsurging, nin groundwater, a well-development technique in which well development technique where a surgeblock is alternately raised and lowered within the well casing or screen, or both, to createinduce a strong inward and outwardmovement of water through the well screen.3.2.23 t
38、ool stringthe drill pipe or drill rod and all attached drilling or development tools used in the borehole or well.3.2.24 turbiditycloudiness in water due to suspended and colloidal material.3.1.14 well developmentdevelopment, nin groundwater, the act of repairing damage to the borehole addressing po
39、tentialformation damage caused by the drilling process andand well installation process by removing fine-grained materialssediment ordrilling fluids, or both, from formation materials so that natural hydraulic conditions are restored and in situ geologic formationand filter pack such that the evalua
40、ted in situ aquifer hydrogeologic parameters are more likely to be representative of the assumedpre-drilling/monitor well installation conditions and overall well yields are enhanced.4. Significance and Use4.1 A properlycorrectly designed, installed, and developed groundwater monitoring well, constr
41、ucted in accordance withPractice D5092 should provide the following: representative samples of groundwater that can be analyzed to determine physicalproperties and water-quality water quality parameters of the sample or potentiometric levels that are representative of the totalhydraulic head of that
42、 portion of the aquifer screened by the well, or both. Such a The well may also be utilized for conductingaquifer performance tests used for the purpose of determining the hydraulichydrogeologic properties of the geologic materialstargeted hydrostratigraphic unit in which the well has been completed
43、.NOTE 1An extensive research program on annular sealants was conducted from 2001 through 2009 and in subsequent years by the Nebraska GroutTask Force (Lackey et al., 2009 and State of California, 2015). This research included cement and bentonite grouts and the use of pellets and chips. Thegeneral f
44、inding of the study indicates all sealing methods suffer from some shrinkage in the portion of the well in the unsaturated zone. The best groutswere cement-sand, bentonite chips, neat cements, and bentonite slurries with more than 20 percent solids. Especially problematic is the use of low solidscon
45、tent bentonite slurries in the unsaturated zone leading to a prohibition on their use in California (State of California, 2015). It is also highlyrecommended that State and Federal codes/regulations regarding seals within the unsaturated zone be evaluated prior to design to ensure codes are met.4.2
46、Well development is an important component of monitoring well pletions. Monitoring wells installed inaquifers should be sufficiently developed to ensuresuch that they serve their intended objectives. Well development methods varywith the physical characteristics of the geologic formation targeted hy
47、drostratigraphic unit in which the monitoring well isscreened, the construction details of the well, the drilling method usedutilized during the construction of the borehole in which thewell is installed, prior to well installation, and the quality of the water.groundwater. The development method fo
48、r each individualmonitoring well should be selected from among the several methods described in this guide and should be employed by the wellconstruction contractor or the person responsible for qualified personnel in responsible charge of the monitoring well completion.4.3 The importance of well de
49、velopment in monitoring wells cannot be overestimated; all too often development isoveresti-mated. If a monitoring well is inherited with a project, it is best for the well construction contractor or the qualified personnel toconsider the possibility that well development was not performed or is carried out inadequately. was carried out inadequately,which may influence both previous and future sampling results if the wells were not redeveloped and/or appropriate documentationof well development cannot be obtained. Proper an
