1、Designation: D 5787 95 (Reapproved 2000)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 (e) 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 nat
3、ural 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 dat
5、a. 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 locatio
6、ns, such as piezometers, per-meameters, temperature or moisture monitors, or seismicdevices to provide protection.1.4 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 pr
7、ofessional 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 of
8、a 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. Referenced Documents2.1 ASTM Standards:C 150 Specification for Portland Cement2C 294 Descriptive Nomenclature of Constituents of Natura
9、lMineral Aggregates3D 5092 Design and Installation of Ground Water Monitor-ing Wells in Aquifers43. Terminology3.1 Definitions:3.1.1 barrierany device that physically prevents access ordamage to an area.3.1.2 barrier markersplastic, or metal posts, often inbright colors, placed around a monitoring w
10、ell 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 around a well location to protect the well fromphysical damage, such as from vehicles.3.1.4 boreholea circular open or uncas
11、ed subsurface holecreated by drilling.3.1.5 casingpipe, finished in sections with either threadedconnections or bevelled edges to be field welded, which isinstalled temporarily or permanently to counteract caving, toadvance the borehole, or to isolate the zone being monitored, ora combination thereo
12、f.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 protectionto the well and restrict unauthorized access into the well.3.1.7 riserthe pipe extending from the well screen to orabove
13、 the ground surface.3.1.8 sealed capa sealable riser cap, normally gasketed orsealed, that is 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 adequatel
14、y designed and installed surface protection1This 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 Sept. 10, 1995. Published January 1996.2Annual Book
15、 of ASTM Standards, Vol 04.01.3Annual Book of ASTM Standards, Vol 04.02.4Annual Book of ASTM Standards, Vol 04.08.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.system will mitigate the consequences of naturally or mancaused damages
16、 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 monitoringwell, the pre
17、sence 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 Information determine
18、d 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 wellidentification.5. Desig
19、n 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 The factors identified
20、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.5.3 In determining the
21、 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 period, the protection
22、 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 thefollowing sections
23、.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 several feet around the ca
24、sing 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 such that anyanticipate
25、d 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 posts are frequentlyused i
26、n 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 completionsleading to damage o
27、f 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, warn individualsof the we
28、ll 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 monitoring well. Signs
29、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 exists for water usage,
30、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.5.3.1.5 Recessed or Subsurface cas
31、ings may be used tomitigate impact damage by allowing the vehicles to pass over.FIG. 1 Example of Protective DesignD 5787 95 (2000)2Frequently used techniques include recessing the casing belowground level, using commercially available covers. These maytake the form of valve pits or manholes, as exa
32、mples. 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 perspective. Disadvan
33、tages 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 cases, such as in locat
34、ion 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, personnel protection requi
35、rements 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 minimal costs, ease ofremo
36、val 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 the data that the well
37、 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 used to protect the wel
38、l 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 philosophy that what cant
39、be 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 ground can be used tod
40、isguise 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 undetected, and thatsamp
41、ling 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 quality can vary from relat
42、ively 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 consideration. Constructio
43、n 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. Aconcrete apron or grout col
44、lar 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, concrete walls, or en
45、closure 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 well and the data, (f
46、or 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 evaluating the data d
47、erived 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 disturbed between sampl
48、ings. 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
49、 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 the protective casing several feet below the shearline. Additional protection may be gained by driving piling orposts through the surface layer and below the shear line toanchor the surface. Protection and maintenance of wells inslide areas can be expensive and may result in only delayingthe loss of the well.5.3.4 Freeze Damage
