1、Designation: D 5787 95 (Reapproved 2009)Standard Practice forMonitoring Well Protection1This standard is issued under the fixed designation D 5787; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number
2、 in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.INTRODUCTIONThis practice for monitoring well protection is provided to promote durable and reliable protectionof installed monitoring wells against natu
3、ral and man caused damage. The practices contained promotethe development and planning of monitoring well protection during the design and installation stage.1. Scope1.1 This practice identifies design and construction consid-erations to be applied to monitoring wells for protection fromnatural and
4、man caused damage or impacts.1.2 The installation and development of a well is a costlyand detailed activity with the goal of providing representativesamples and data throughout the design life of the well.Damages to the well at the surface frequently result in loss ofthe well or changes in the data
5、. This standard provides foraccess control so that tampering with the installation should beevident. The design and installation of appropriate surfaceprotection will mitigate the likelihood of damage or loss.1.3 This practice may be applied to other surface or subsur-face monitoring device location
6、s, such as piezometers, per-meameters, temperature or moisture monitors, or seismicdevices to provide protection.1.4 The values stated in inch-pound units are to be regardedas standard. No other units of measurement are included in thisstandard.1.5 This practice offers a set of instructions for perf
7、ormingone or more specific operations. This document cannot replaceeducation or experience and should be used in conjunctionwith professional judgment. Not all aspects of this practice maybe applicable in all circumstances. This ASTM standard is notintended to represent or replace the standard of ca
8、re by whichthe adequacy of a given professional service must be judged,nor should this document be applied without consideration ofa projects many unique aspects. The word “Standard” in thetitle of this document means only that the document has beenapproved through the ASTM consensus process.2. Refe
9、renced Documents2.1 ASTM Standards:2C 150 Specification for Portland CementC 294 Descriptive Nomenclature for Constituents of Con-crete AggregatesD 5092 Practice for Design and Installation of GroundWater Monitoring Wells3. Terminology3.1 Definitions:3.1.1 barrierany device that physically prevents
10、access ordamage to an area.3.1.2 barrier markersplastic, or metal posts, often inbright colors, placed around a monitoring well to aid inidentifying or locating the well.3.1.3 barrier postssteel pipe, typically from 4 to 12inches in diameter and normally filled with concrete or groutthat are placed
11、around a well location to protect the well fromphysical damage, such as from vehicles.3.1.4 boreholea circular open or uncased subsurface holecreated by drilling.3.1.5 casingpipe, finished in sections with either threadedconnections or bevelled edges to be field welded, which isinstalled temporarily
12、 or permanently to counteract caving, toadvance the borehole, or to isolate the zone being monitored, ora combination thereof.3.1.6 casing, protectivea section of larger diameter pipethat is emplaced over the upper end of a smaller diametermonitoring well riser or casing to provide structural protec
13、tionto the well and restrict unauthorized access into the well.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 April 1, 2009. Published April
14、2009. Originallyapproved in 1995. Last previous edition approved in 2000 as D 5787 95 (2000).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
15、Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.3.1.7 riserthe pipe extending from the well screen to orabove the ground surface.3.1.8 sealed capa sealable riser cap, normally gasketed orsealed, that i
16、s designed to prevent water or other substancesfrom entering into, or out of the well riser.3.1.9 vented capa cap with a small hole that is installed ontop of the riser.4. Significance and Use4.1 An adequately designed and installed surface protectionsystem will mitigate the consequences of naturall
17、y or mancaused damages which could otherwise occur and result ineither changes to the data, or complete loss of the monitoringwell.4.2 The extent of application of this practice may dependupon the importance of the monitoring data, cost of monitoringwell replacement, expected or design life of the m
18、onitoringwell, the presence or absence of potential risks, and setting orlocation of the well.4.3 Monitoring well surface protection should be a part ofthe well design process, and installation of the protectivesystem should be completed at the time of monitoring wellinstallation and development.4.4
19、 Information determined at the time of installation of theprotective system will form a baseline for future monitoringwell inspection and maintenance. Additionally, elements of theprotection system will satisfy some regulatory requirementssuch as for protection of near surface ground water and welli
20、dentification.5. Design Considerations5.1 The design of a monitoring well protective system islike other design processes, where the input considerations aredetermined and the design output seeks to remedy or mitigatethe negative possibilities, while taking advantage of the sitecharacteristics.5.2 T
21、he factors identified in this practice should be consid-ered during the design of the monitoring well protectivesystem. The final design should be included in the monitoringwell design and installation documentation and be completedand verified during the final completion and development ofthe well.
22、5.3 In determining the level or degree of protection re-quired, the costs and consequences, such as loss of data orreplacement of the well, must be weighed against the probabil-ity of occurrence and the desired life of the well. Formonitoring wells which will be used to obtain data over a shorttime
23、period, the protection system may be minimal. For wellswhich are expected to be used for an indefinite period, are in avulnerable location, and for which the costs of lost data couldbe high, the protective system should be extensive. Factors toconsider and methods of mitigating them are presented in
24、 thefollowing sections.5.3.1 Impact DamagesPhysical damages resulting fromconstruction equipment, livestock, or vehicles striking themonitoring well casing frequently occur. Protective devicesand approaches include:5.3.1.1 Extra heavy protective casings with a reinforcedconcrete apron extending seve
25、ral feet around the casing may bean acceptable design in those areas where frost heave is not aproblem. The principle behind this is to design the protectivecasing so that it will be able to withstand the impact of vehicleswithout damage to the riser within.5.3.1.2 Barrier Posts placed in an array s
26、uch that anyanticipated vehicle can not pass between them to strike theprotective casing. Barrier posts are typically filled with con-crete and set in post holes several feet deep which arebackfilled with concrete. Barrier posts typically extend from 3to 5 feet above the ground surface. Barrier post
27、s are frequentlyused in and around industrial or high vehicle traffic areas. Costsfor installation can be substantial however they provide a highdegree of protection for exposed wells. Cost of removal atdecommissioning can also be substantial.NOTE 1Cattle frequently rub against above ground completi
28、onsleading to damage of unprotected casings. Concrete filled posts or drivenT-posts, wrapped with barbed wire, are frequently used.5.3.1.3 Barrier Markers are relatively lightweight metal oroften plastic posts which provide minimal impact resistancebut which by their color, location, and height, war
29、n individualsof the well presence. The use of barrier markers is effective inareas that are well protected from impact type damage by otherfeatures, such as surrounding structures or fences. They arerelatively inexpensive to install.5.3.1.4 SignsAn inexpensive means of identifying thepresence of a m
30、onitoring well. Signs provide protection onlyby warning of the well presence. Signs may be required insome circumstances and appropriate in others. Wells known tocontain hazardous, radioactive, or explosive compounds shouldbe marked to warn sampling personnel of potential dangers.When a potential ex
31、ists for water usage, signage indicating thatthe water is non-potable and is utilized strictly as a monitoringwell, and not for any other purpose, may be appropriate.Disadvantages of signs are that they may be ignored, are oftendifficult to maintain, and may invite vandalism to the well.FIG. 1 Examp
32、le of Protective DesignD 5787 95 (2009)25.3.1.5 Recessed or Subsurface casings may be used tomitigate impact damage by allowing the vehicles to pass over.Frequently used techniques include recessing the casing belowground level, using commercially available covers. These maytake the form of valve pi
33、ts or manholes, as examples. Advan-tages include both protecting the well while minimizing theinterference to surface traffic, such as in parking lots or urbanareas and screening the well from view. Using this technique,wells may be located in the most desired locations from aground-water monitoring
34、 perspective. Disadvantages includethe need to assure surface drainage does not enter the well riser,either by maintaining positive drainage or by using a sealedriser cap (or both). When the risk is from the influx of surfacewater, drains below the level of the riser should be installed. Inextreme c
35、ases, such as in location with high ground-waterlevels or potential drainage from surrounding areas, automaticsump pumps may be required. Consideration should be givento the sampling personnel who will require adequate space toperform sampling, particularly in manhole situations. Addi-tionally, pers
36、onnel protection requirements from working in aconfined space should be considered.5.3.1.6 Fencing, such as commercial chainlink type fencesmay provide adequate protection in areas with light risk fromvehicles, but where people or animals may interfere or affectthe well. Advantages are relative mini
37、mal costs, ease ofremoval or opening. Disadvantages include maintenance, ad-equacy of protection from hard vehicle impacts, and visual andtraffic interference.5.3.2 VandalismDamage from vandals can take twoforms, those which seek to damage or destroy the well itself,and those which intend to damage
38、the data that the well mayprovide. Theft of sampling pumps, loss of access to the riser,plugging of the well with foreign debris, or injection of foreignmaterials or chemicals are potential results of vandalism.5.3.2.1 Physical damage to the well can be minimized withmany of the same techniques as u
39、sed to protect the well fromimpact damages. Generally two techniques can be used toprotect a well from physical damage, one, by hiding orcamouflaging the well, the other by constructing the surfaceprotection of the well with multiple physical barriers. Hiding orcamouflaging the well utilizes the phi
40、losophy that what cantbe found cant be damaged. Camouflage techniques includeenclosing the well in manholes or sumps, planting shrubs orvegetation to shield the well from view, enclosing the well inanother structure, such as inside a raised planter or a smallshed. Color characteristics of the above
41、ground can be used todisguise the well or to assist in making it blend into thesurroundings. Costs for camouflage can vary widely, but aregenerally minimal when included with other protections. Dis-advantages are that if found, the well is still susceptible todamage by vandals, that damage may be un
42、detected, and thatsampling personnel not familiar with the well may havedifficulty locating it.5.3.2.2 Protection from vandalism is generally achieved byconstructing multiple physical barriers. The first barrier shouldalways include a rugged protective casing with a locking cap orlid. The lock quali
43、ty can vary from relatively inexpensive andeasily broken types to more costly high security type locks.Locks used on wells are subject to weather, dirt and deterio-ration. Frequently locks must be cut if not regularly maintainedand the design and selection of the cap and lock should includethis cons
44、ideration. Construction of the hasps, locking lugs, orother mechanisms should be rugged, made of metal and weldedto prevent access to the casing by prying, hammering or othertypical vandalism. The casing should be heavy enough to resistpenetration by bullets in areas where shooting may occur. Aconcr
45、ete apron or grout collar around the casing will providemass to defeat attempts to pull the casing upwards, or side-ways. Additional physical barriers should be added in consid-eration of the location and likelihood of vandalism. Theseinclude locked chainlink fences, use of barbed or concertinawire,
46、 concrete walls, or enclosure inside of buildings or otherfenced or enclosed areas. When placed in below ground levelstructures, such as sumps or manholes, the access covers can beequipped with a lock. Access to keys should be controlled toprevent unauthorized use and entry.5.3.2.3 Protection of the
47、 well and the data, (for example,ground-water level elevations), that the well will provide canbe generally achieved by the physical barriers previouslydescribed. Detection of access to a well should also beconsidered. While not protecting the well and the sample datadirectly, it will be valuable in
48、 evaluating the data derived fromthe well samples. Sampling personnel should be alert andinspect the well and the protective devices for signs ofvandalism. Foil or paper seals can be applied to the riser andcap at the end of each sampling to allow visual verification thatthe riser cap has not been d
49、isturbed between samplings. Sealsare inexpensive and provide assurance of the well integrity andshould be considered for use on all wells.5.3.3 LandslidesMovement of the surface layers of soildue to seismic activity or other changes can result in lateralmovement with the riser being bent or ultimately sheared. Theprimary protection against this type of damage is location.Whenever possible, the well should be located outside of theslide area. When relocation is not possible and the moving soillayer is relatively thin, limited protection may be achieved byextending th
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