1、Designation: C12 16C12 16aStandard Practice forInstalling Vitrified Clay Pipe Lines1This standard is issued under the fixed designation C12; the number immediately following the designation indicates the year of originaladoption or, in the case of revision, the year of last revision.Anumber in paren
2、theses indicates the year of last reapproval.Asuperscriptepsilon () 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 Defense.1. Scope1.1 This practice covers the proper methods of installing vitrified cl
3、ay pipe lines by open trench construction methods in orderto fully utilize the structural properties of such pipe.1.2 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematicalconversions to SI units that are provided for information only a
4、nd are not considered standard.1.3 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 safety and health practices and determine the applicability of regulatorylimitations
5、 prior to use.2. Referenced Documents2.1 ASTM Standards:2C301 Test Methods for Vitrified Clay PipeC403/C403M Test Method for Time of Setting of Concrete Mixtures by Penetration ResistanceC425 Specification for Compression Joints for Vitrified Clay Pipe and FittingsC700 Specification for Vitrified Cl
6、ay Pipe, Extra Strength, Standard Strength, and PerforatedC828 Test Method for Low-Pressure Air Test of Vitrified Clay Pipe LinesC896 Terminology Relating to Clay ProductsC923 Specification for Resilient Connectors Between Reinforced Concrete Manhole Structures, Pipes, and LateralsC1091 Test Method
7、for Hydrostatic Infiltration Testing of Vitrified Clay Pipe LinesD2487 Practice for Classification of Soils for Engineering Purposes (Unified Soil Classification System)D2488 Practice for Description and Identification of Soils (Visual-Manual Procedure)D4832 Test Method for Preparation and Testing o
8、f Controlled Low Strength Material (CLSM) Test CylindersD5821 Test Method for Determining the Percentage of Fractured Particles in Coarse AggregateD6103 Test Method for Flow Consistency of Controlled Low Strength Material (CLSM) (Withdrawn 2013)33. Terminology3.1 GeneralTerminology C896 can be used
9、for clarification of terminology in this specification.3.2 See Fig. 1.DESIGN CONSIDERATIONS4. Supporting Strength4.1 The field supporting strength of vitrified clay pipe is materially affected by the methods of installation. The field supportingstrength of a pipe is defined as its capacity to suppor
10、t dead and live loads under actual field conditions. It is dependent upon twofactors: (1) the inherent strength of the pipe and (2) the bedding of the pipe.1 This practice is under the jurisdiction of ASTM Committee C04 on Vitrified Clay Pipe and is the direct responsibility of Subcommittee C04.20 o
11、n Methods of Test andSpecifications.Current edition approved May 15, 2016Nov. 1, 2016. Published May 2016December 2016. Originally approved in 1915. Last previous edition approved in 20142016 asC12 14.C12 16. DOI: 10.1520/C0012-16.10.1520/C0012-16A.2 For referencedASTM standards, visit theASTM websi
12、te, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.3 The last approved version of this historical standard is referenced on www.astm.org.This document is not an AS
13、TM 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 possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In a
14、ll cases only the current versionof the standard as published by ASTM is to be considered the official document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States14.2 The minimum bearing strength requirement in accordance with Specificat
15、ion C700, as determined by the 3-edge-bearing testof Test Methods C301, is a measure of the inherent strength of the pipe.4.3 The tests used to measure bearing strength determine relative pipe strengths but do not represent actual field conditions.Therefore, an adjustment called a load factor is int
16、roduced to convert minimum bearing strength to field supporting strength. Themagnitude of the load factor depends on how the pipe is bedded. The relationship is:Field supporting strength5minimum bearing strength3load factor4.4 Afactor of safety 1.0 and 1.5 shall be applied to the field supporting st
17、rength to calculate a safe supporting strength. Therelationship is:Safe supporting strength5Field supporting strengthFactor of safety5. External Loads5.1 The external loads on installed vitrified clay pipe are of two general types: (1) dead loads and (2) live loads.5.2 For pipes installed in trenche
18、s at a given depth, the dead load increases as the trench width, measured at the top of the pipe,increases. Pipe failure may result if the design trench width is exceeded. If the trench width exceeds the design width, a higherclass of bedding, stronger pipe, or both, must be investigated.FIG. 1 Term
19、inologyC12 16a25.3 Live loads that act at the ground surface are partially transmitted to the pipe. Live loads may be produced by wheel loading,construction equipment or by compactive effort. Compaction of embedment and backfill materials, beside and above the sewerpipe, produces a temporary live lo
20、ad on the pipe. The magnitude of the live load from compactive effort varies with soil type,degree of saturation, degree of compaction and depth of cover over the pipe. Care must be used in selection of compaction methodsso that the combined dead load and live load does not exceed the field supporti
21、ng strength of the pipe, or cause a change in itsline or grade.NOTE 1For generally accepted criteria and methods for determining loads and supporting strengths, see Gravity Sanitary Sewer Design andConstruction, Water Pollution Control Federation Manual of Practice No. FD-5, American Society of Civi
22、l EngineersManuals and Report onEngineering PracticeNo. 60.46. Bedding and Encasement6.1 Classes of bedding and encasements for pipe in trenches are defined herein. The load factors indicated are for conversionof minimum bearing strength to field supporting strength.6.1.1 The soil groups used in eac
23、h bedding class are defined in Table 1.6.1.2 The gradation for Class I and Class II soil for Class C bedding (Fig. 3) shall have a maximum particle size of 1 in. (25mm).6.1.3 The gradation for Class I and Class II bedding material for Class B (Fig. 4), Crushed Stone Encasement (Fig. 5), andCLSM inst
24、allation (Fig. 6) shall be as follows:100 % passing a 1 in. (25 mm) sieve40-60 % passing a 34 in. (19 mm) sieve0-25 % passing a 38 in. (9.5 mm) sieve6.1.4 For Class I, all particle faces shall be fractured.6.1.5 Class II soils shall have a minimum of one fractured face. For Class B (Fig. 4), Crushed
25、 Stone Encasement (Fig. 5), andCLSM installations (Fig. 6) where high, or changing water tables, or both, are present; Class II material shall have a minimumpercentage by particle count of one fractured face-100 %, two fractured faces-85 %, and three fractured faces-65 % in accordancewith Test Metho
26、d D5821.6.1.6 Class I material is considered to be more stable and provide better support than Class II material that have some roundededges.6.1.7 All bedding material shall be shovel-sliced so the material fills and supports the haunch area and encases the pipe to thelimits shown in the trench diag
27、rams.6.2 Class D (Fig. 2):4 Available from American Society of Civil Engineers (ASCE), 1801 Alexander Bell Dr., Reston, VA 20191, http:/www.asce.org.TABLE 1 Uniform Soil Groups for Pipe InstallationNOTE 1Soil Classification descriptions and symbols are in accordance with Practice D2487 and Practice
28、D2488.NOTE 2For Class I, all particle faces shall be fractured.NOTE 3Materials such as broken coral, shells, slag, and recycled concrete (with less than 12 % passing a #200 sieve) should be treated as Class IIsoils.NOTE 4Class V soil is not suitable for use as a bedding or initial backfill material.
29、Class I crushed rock100 % passing 1-12 in. (38 mm) sieve,/= 30 % retained on #200 sieveML, CLClass IV fine-grained soilsor any soil beginning with one of these symbolswith 30 % retained on #200 sieveML, CLClass V fine-grained soils, organic soilshigh compressibility silts and clays, organic soilMH,
30、CH, OL, OH, PtC12 16a36.2.1 The pipe shall be placed on a firm and unyielding trench bottom with bell holes provided (Fig. 7).6.2.2 The initial backfill shall be either Class I, II, III, or IV having a maximum particle size of 1 in. (25 mm).6.2.3 The load factor for Class D bedding is 1.1.6.3 Class
31、C (Fig. 3):6.3.1 The pipe shall be bedded in Class I or Class II soil. Refer to 6.1.2 and Table 2 for requirements. Sand is suitable as abedding material in a total sand environment, but may be unsuitable where high and rapidly changing water tables are present inthe pipe zone. Sand may also be unde
32、sirable in a trench cut by blasting or in trenches through clay type soil. Regardless of thetrench condition or bedding class, the maximum load factor for sand bedding is 1.5. The bedding shall have a minimum thicknessbeneath the pipe of 4 in. (100 mm) or one sixth of the outside diameter of the pip
33、e, whichever is greater, and shall extend up thehaunches of the pipe one sixth of the outside diameter of the pipe.6.3.2 The initial backfill shall be either Class I, II, III, or IV having maximum particle size of 1-12 in. (38 mm) (see Table 2).6.3.3 The load factor for Class C bedding is 1.5.6.4 Cl
34、ass B (Fig. 4):FIG. 2 Class DFIG. 3 Class CC12 16a46.4.1 The pipe shall be bedded in Class I or Class II soil. Refer to 6.1.3, 6.1.5, and Table 2 for requirements. The bedding shallhave a minimum thickness beneath the pipe of 4 in. (100 mm) or one sixth of the outside diameter of the pipe, whichever
35、 is greater,and shall extend up the haunches of the pipe to the springline.6.4.2 The initial backfill shall be either Class I, II, III, or IV having a maximum particle size of 1-12 in. (38 mm).6.4.3 The load factor for Class B bedding is 1.9.6.5 Crushed Stone Encasement (Fig. 5):6.5.1 The pipe shall
36、 be bedded in Class I or Class II soil. Refer to 6.1.3, 6.1.5, and Table 2 for requirements. The bedding shallhave a minimum thickness beneath the pipe of 4 in. (100 mm) or one sixth of the outside diameter of the pipe, whichever is greater,and shall extend upward to a horizontal plane at the top of
37、 the pipe barrel. Material shall be carefully placed into the pipe haunches.6.5.2 Sufficient material shall be placed so that the bedding extends to a horizontal plane at the top of the pipe barrel followingremoval of any trench sheeting or boxes.6.5.3 The initial backfill shall be either Class I, I
38、I, III, or IV having a maximum particle size of 1-12 in. (38 mm).6.5.4 The load factor for crushed stone encasement is 2.2.6.6 Controlled Low Strength Material (Fig. 6)Controlled low strength material (CLSM) is used as an effective material forthe bedding of vitrified clay pipe.6.6.1 The pipe shall
39、be bedded on Class I or Class II soil. Refer to 6.1.3, 6.1.5, and Table 2 for requirements. The bedding shallhave a minimum thickness beneath the pipe of 4 in. (100 mm) or one sixth of the outside diameter of the pipe, whichever is greater.FIG. 4 Class BFIG. 5 Crushed Stone EncasementC12 16a56.6.2 F
40、or pipe diameters 8 to 21 in. (205 to 535 mm), CLSM shall extend a minimum of 9 in. (230 mm) on each side of thepipe barrel. For pipe diameters 24 in. (610 mm) and larger, CLSM shall extend a minimum of 12 in. (305 mm) on each side ofthe pipe barrel (Fig. 6).6.6.3 When placed, CLSM shall have a meas
41、ured flowability of 861 in. (205625 mm) spread diameter as determined byTestMethod D6103.6.6.4 28-day compressive strength shall be 100 to 300 psi (0.69 to 2.07 MPa) as determined by Test Method D4832.6.6.5 CLSM shall be directed to the top of the pipe to flow down equally on both sides to prevent m
42、isalignment. Place CLSMto the top of the pipe barrel.6.6.6 The initial backfill shall be either Class I, II, III, or IV having a maximum particle size of 1-12 in. (38 mm).6.6.7 Initial backfill shall only commence after a 500 psi (3.45 MPa) minimum penetrometer reading is achieved as determinedby Te
43、st Method C403/C403M. The penetrometer shall have a maximum load capability of 700 psi (4.83 MPa) and have a 1 in.2 1in. (645 mm2 25 mm) long cylinder foot attached to a 14 in. (6 mm) diameter pin.6.6.8 The load factor for controlled low strength material is 2.8.6.7 Concrete Cradle (Fig. 8)6.7.1 The
44、 pipe shall be bedded in a cradle of reinforced concrete having a thickness under the barrel of at least 6 in. (150 mm)or one fourth of the outside diameter of the pipe, whichever is greater, and extending up the haunches to a height of at least onehalf the outside diameter of the pipe. The cradle w
45、idth shall be at least equal to the outside diameter of the pipe plus 4 in. (100This type of construction requires the fill to extend from the pipe to the trench wall, not to extend above the top of the pipe or below the bottom of the pipe. Where nativesoils are expansive, further investigation may
46、be necessary.FIG. 6 Controlled Low Strength Material (CLSM)FIG. 7 Uniform Pipe SupportC12 16a6mm) on each side or one and one fourth times the outside diameter of the pipe, whichever is greater. If the trench width is greaterthan either of these dimensions, concrete may be placed to full trench widt
47、h.6.7.2 The initial backfill shall be either Class I, II, III, or IV having a maximum particle size of 1-12 in. (38 mm).6.7.3 The load factor for ClassAconcrete cradle bedding is 3.4 for reinforced concrete with p = 0.4 %, where p is the percentageof the area of transverse steel to the area of concr
48、ete at the bottom of the pipe barrel as shown in Fig. 8.6.8 Concrete Encasement:6.8.1 There are specific sites where concrete encasement may be desirable. Concrete encasement shall completely surround thepipe and shall have a minimum thickness, at any point, of one fourth of the outside diameter of
49、the pipe or 4 in. (100 mm),whichever is greater.6.8.2 The encasement shall be designed by the engineer to suit the specific use.TABLE 2 Allowable Bedding Material and Initial Backfill Per Bedding ClassBedding Class Allowable Bedding Material Allowable Initial BackfillClassTable 1Gradation Maximum Particle Size ClassTable 1Maximum Particle SizeClass D N/A N/A N/A I, II, III, or IV 1 in. (25 mm)Class C I or II 1 in. (25 mm) I, II, III, or IV 1-12 in. (38 mm)Class BI or II 100 % passing a 1 in.(25 mm) sieve1 in. (25 mm) I, II, III, or IV 1-12 in.
