1、Designation: D2321 141An American National StandardStandard Practice forUnderground Installation of Thermoplastic Pipe for Sewersand Other Gravity-Flow Applications1This standard is issued under the fixed designation D2321; the number immediately following the designation indicates the year oforigin
2、al adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the U.S. Department of
3、 Defense.1NOTEX2.4 was editorially corrected in September 2014.1. Scope*1.1 This practice provides recommendations for the instal-lation of buried thermoplastic pipe used in sewers and othergravity-flow applications. These recommendations are in-tended to ensure a stable underground environment for
4、ther-moplastic pipe under a wide range of service conditions.However, because of the numerous flexible plastic pipe prod-ucts available and the inherent variability of natural groundconditions, achieving satisfactory performance of any oneproduct may require modification to provisions containedherei
5、n to meet specific project requirements.1.2 The scope of this practice necessarily excludes productperformance criteria such as minimum pipe stiffness, maxi-mum service deflection, or long term strength. Thus, it isincumbent upon the product manufacturer, specifier, or projectengineer to verify and
6、assure that the pipe specified for anintended application, when installed according to proceduresoutlined in this practice, will provide a long term, satisfactoryperformance according to criteria established for that applica-tion. A commentary on factors important in achieving asatisfactory installa
7、tion is included in Appendix X1.NOTE 1Specific paragraphs in the appendix are referenced in the bodyof this practice for informational purposes.NOTE 2The following ASTM standards may be found useful inconnection with this practice: Practice D420, Test Method D1556, MethodD2216, Specification D2235,
8、Test Method D2412, Specification D2564,Practice D2657, Practice D2855, Test Methods D2922, Test MethodD3017, Practice F402, Specification F477, Specification F545, andSpecification F913.NOTE 3Most Plumbing Codes and some Building Codes haveprovisions for the installation of underground “building dra
9、ins andbuilding sewers.” See them for plumbing piping applications.1.3 UnitsThe values stated in inch-pound units are to beregarded as standard. The values given in parentheses aremathematical conversions to SI units that are provided forinformation only and are not considered standard.1.4 This stan
10、dard 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 and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 A
11、STM Standards:2D8 Terminology Relating to Materials for Roads and Pave-mentsD420 Guide to Site Characterization for Engineering Designand Construction Purposes (Withdrawn 2011)3D653 Terminology Relating to Soil, Rock, and ContainedFluidsD698 Test Methods for Laboratory Compaction Character-istics of
12、 Soil Using Standard Effort (12 400 ft-lbf/ft3(600kN-m/m3)D1556 Test Method for Density and Unit Weight of Soil inPlace by Sand-Cone MethodD2216 Test Methods for Laboratory Determination of Water(Moisture) Content of Soil and Rock by MassD2235 Specification for Solvent Cement for Acrylonitrile-Butad
13、iene-Styrene (ABS) Plastic Pipe and FittingsD2412 Test Method for Determination of External LoadingCharacteristics of Plastic Pipe by Parallel-Plate LoadingD2487 Practice for Classification of Soils for EngineeringPurposes (Unified Soil Classification System)D2488 Practice for Description and Identi
14、fication of Soils(Visual-Manual Procedure)D2564 Specification for Solvent Cements for Poly(VinylChloride) (PVC) Plastic Piping Systems1This practice is under the jurisdiction of ASTM Committee F17 on PlasticPiping Systems and is the direct responsibility of Subcommittee F17.62 on Sewer.Current editi
15、on approved Aug. 1, 2014. Published September 2014. Originallyapproved in 1989. Last previous edition approved in 2011 as D2321 11. DOI:10.1520/D2321-14E01.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of AST
16、MStandards volume information, refer to the standards Document Summary page onthe ASTM website.3The last approved version of this historical standard is referenced onwww.astm.org.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO
17、Box C700, West Conshohocken, PA 19428-2959. United States1D2657 Practice for Heat Fusion Joining of Polyolefin Pipeand FittingsD2855 Practice for Making Solvent-Cemented Joints withPoly(Vinyl Chloride) (PVC) Pipe and FittingsD2922 Test Methods for Density of Soil and Soil-Aggregatein Place by Nuclea
18、r Methods (Shallow Depth) (With-drawn 2007)3D3017 Test Method for Water Content of Soil and Rock inPlace by Nuclear Methods (Shallow Depth)D3839 Guide for Underground Installation of “Fiberglass”(Glass-Fiber Reinforced Thermosetting-Resin) PipeD4318 Test Methods for Liquid Limit, Plastic Limit, andP
19、lasticity Index of SoilsF402 Practice for Safe Handling of Solvent Cements,Primers, and Cleaners Used for Joining ThermoplasticPipe and FittingsF412 Terminology Relating to Plastic Piping SystemsF477 Specification for Elastomeric Seals (Gaskets) for Join-ing Plastic PipeF545 Specification for PVC an
20、d ABS Injected Solvent Ce-mented Plastic Pipe Joints (Withdrawn 2001)3F913 Specification for Thermoplastic Elastomeric Seals(Gaskets) for Joining Plastic PipeF1668 Guide for Construction Procedures for Buried PlasticPipe2.2 AASHTO Standard:4AASHTO M145 Classification of Soils and Soil AggregateMixtu
21、res3. Terminology3.1 GeneralDefinitions used in this practice are in accor-dance with Terminologies F412 and D8 and Terminology D653unless otherwise indicated.3.2 Definitions:3.2.1 Terminology D653 definitions used in this standard:3.2.2 compaction curve (Proctor curve) (moisture-densitycurve)the cu
22、rve showing the relationship between the dryunit weight (density) and the water content of a soil for a givencompactive effort.3.2.3 maximum unit weightthe dry unit weight defined bythe peak of a compaction curve.3.2.4 optimum water contentthe water content at which asoil can be compacted to a maxim
23、um dry unit weight by agiven compactive effort.3.2.5 percent compactionthe ratio, expressed as apercentage, of: (1) dry unit weight of a soil, to (2) maximumunit weight obtained in a laboratory compaction test.3.3 Definitions of Terms Specific to This Standard:3.3.1 aggregatea granular material of m
24、ineral composi-tion such as sand, gravel, shell, slag or crushed stone (seeTerminology D8).3.3.2 deflectionany change in the inside diameter of thepipe resulting from installation and imposed loads. Deflectionmay be either vertical or horizontal and is usually reported asa percentage of the base (un
25、deflected) inside pipe diameter.3.3.3 engineerthe engineer in responsible charge of thework or his duly recognized or authorized representative.3.3.4 foundation, bedding, haunching, initial backfill, finalbackfill, pipe zone, excavated trench widthSee Fig. 1 formeaning and limits, and trench termino
26、logy.3.3.5 manufactured aggregatesaggregates such as slagthat are products or byproducts of a manufacturing process, ornatural aggregates that are reduced to their final form by amanufacturing process such as crushing.3.3.6 modulus of soil reaction (E)an empirical value usedin the Iowa deflection fo
27、rmula that defines the stiffness of thesoil embedment around a buried pipe3.3.7 open-graded aggregatean aggregate that has a par-ticle size distribution such that, when it is compacted, the voidsbetween the aggregate particles, expressed as a percentage ofthe total space occupied by the material, ar
28、e relatively large.3.3.8 processed aggregatesaggregates that are screened,washed, mixed, or blended to produce a specific particle sizedistribution.3.3.9 secant constrained soil modulus (Ms)- a value forsoil stiffness determined as the secant slope of the stress-straincurve of a one-dimensional comp
29、ression test; Mscan be usedin place of E in the Iowa deflection formula.3.3.10 standard proctor densitythe maximum dry unitweight of soil compacted at optimum moisture content, asobtained by laboratory test in accordance with Test MethodsD698.4. Significance and Use4.1 This practice is for use by de
30、signers and specifiers,installation contractors, regulatory agencies, owners, and in-spection organizations who are involved in the construction of4Available from American Association of State Highway and TransportationOfficials (AASHTO), 444 N. Capitol St., NW, Suite 249, Washington, DC 20001,http:
31、/www.transportation.org.* See 7.6 Minimum CoverFIG. 1 Trench Cross SectionD2321 1412sewers and other gravity-flow applications that utilize flexiblethermoplastic pipe. As with any standard practice, modifica-tions may be required for specific job conditions or for speciallocal or regional conditions
32、. Recommendations for inclusion ofthis practice in contract documents for a specific project aregiven in Appendix X2.5. Materials5.1 ClassificationSoil types used or encountered in bury-ing pipes include those classified in Table 1 and natural,manufactured, and processed aggregates. The soil classif
33、ica-tions are grouped into soil classifications in Table 2 based onthe typical soil stiffness when compacted. Class I indicates asoil that generally provides the highest soil stiffness at anygiven percent compaction, and provides a given soil stiffnesswith the least compactive effort. Each higher-nu
34、mber soil classprovides successively less soil stiffness at a given percentcompaction and requires greater compactive effort to provide agiven level of soil stiffnessNOTE 4See Practices D2487 and D2488 for laboratory and fieldvisual-manual procedures for identification of soils.NOTE 5Processed mater
35、ials produced for highway construction,including coarse aggregate, base, subbase, and surface coarse materials,when used for foundation, embedment, and backfill, should be categorizedin accordance with this section and Table 1 in accordance with particlesize and gradation.5.2 Installation and UseTab
36、le 3 provides recommenda-tions on installation and use based on soil classification andlocation in the trench. Soil Classes I to IV should be used asrecommended in Table 3. Soil Class V, including clays and siltswith liquid limits greater than 50, organic soils, and frozensoils, shall be excluded fr
37、om the pipe-zone embedment.5.2.1 Class IClass I materials provide maximum stabilityand pipe support for a given percent compaction due to the lowcontent of sand and fines. With minimum effort these materialscan be installed at relatively high-soil stiffnesses over a widerange of moisture contents. I
38、n addition, the high permeabilityof Class I materials may aid in the control of water, and thesematerials are often desirable for embedment in rock cuts wherewater is frequently encountered. However, when ground-waterflow is anticipated, consideration should be given to thepotential for migration of
39、 fines from adjacent materials into theopen-graded Class I materials. (See X1.8.)5.2.2 Class IIClass II materials, when compacted, providea relatively high level of pipe support; however, open-gradedgroups may allow migration and the sizes should be checkedfor compatibility with adjacent material. (
40、See X1.8.)5.2.3 Class IIIClass III materials provide less support fora given percent compaction than Class I or Class II materials.Higher levels of compactive effort are required and moisturecontent must be near optimum to minimize compactive effortand achieve the required percent compaction. These
41、materialsprovide reasonable levels of pipe support once proper percentcompaction is achieved.5.2.4 Class IVClass IV materials require a geotechnicalevaluation prior to use. Moisture content must be near opti-mum to minimize compactive effort and achieve the requiredpercent compaction. Properly place
42、d and compacted, Class IVmaterials can provide reasonable levels of pipe support;however, these materials may not be suitable under high fills,surface-applied wheel loads, or under high-energy-level vibra-tory compactors and tampers. Do not use where water condi-tions in the trench may prevent prope
43、r placement and compac-tion.NOTE 6The term “high energy level vibratory compactors andtampers” refers to compaction equipment that might deflect or distort thepipe more than permitted by the specifications or the manufacturer.5.2.5 Class VClass V materials should be excluded frompipe-zone embedment.
44、5.3 Moisture Content of Embedment MaterialsThe mois-ture content of embedment materials must be controlled topermit placement and compaction to required levels. For soilswith low permeability (that is, Class III and Class IV and someborderline Class II soils), moisture content is normally con-trolle
45、d to 6 3 % of optimum (see Test Method D698). Thepracticality of obtaining and maintaining the required limits onmoisture content is an important criterion for selectingmaterials, since failure to achieve required percent compaction,especially in the pipe zone embedment, may result in excessivedefle
46、ction.5.4 Maximum Particle SizeMaximum particle size forembedment is limited to material passing a 112-in. (37.5-mm)sieve (see Table 2). To enhance placement around smalldiameter pipe and to prevent damage to the pipe wall, a smallermaximum size may be required (see X1.9). When final backfillcontain
47、s rocks, cobbles, etc., the engineer may require greaterinitial backfill cover levels (see Fig. 1).6. Trench Excavation6.1 GeneralProcedures for trench excavation that areespecially important in flexible thermoplastic pipe installationsare given herein.6.1.1 ExcavationExcavate trenches to ensure tha
48、t sideswill be stable under all working conditions. Slope trench wallsor provide supports in conformance with all local and nationalstandards for safety. Open only as much trench as can be safelymaintained by available equipment. Backfill all trenches assoon as practicable, but not later than the en
49、d of each workingday.6.2 Water ControlDo not lay or embed pipe in standing orrunning water. At all times prevent runoff and surface waterfrom entering the trench.6.2.1 Ground WaterWhen groundwater is present in thework area, dewater to maintain stability of in-situ and importedmaterials. Maintain water level below pipe bedding and foun-dation to provide a stable trench bottom. Use, as appropriate,sump pumps, well points, deep wells, geofabrics, perforatedunderdrains, or stone blankets of sufficient thickness to removeand control water in t
