1、Designation: C12 16Standard 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 parentheses
2、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 installingvitrified clay pipe
3、lines in order to fully utilize the structuralproperties of such pipe.1.2 The values stated in inch-pound units are to be regardedas standard. The values given in parentheses are mathematicalconversions to SI units that are provided for information onlyand are not considered standard.1.3 This standa
4、rd 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 AST
5、M Standards:2C301 Test Methods for Vitrified Clay PipeC403/C403M Test Method for Time of Setting of ConcreteMixtures by Penetration ResistanceC425 Specification for Compression Joints for Vitrified ClayPipe and FittingsC700 Specification for Vitrified Clay Pipe, Extra Strength,Standard Strength, and
6、 PerforatedC828 Test Method for Low-Pressure Air Test of VitrifiedClay Pipe LinesC896 Terminology Relating to Clay ProductsC1091 Test Method for Hydrostatic Infiltration Testing ofVitrified Clay Pipe LinesD2487 Practice for Classification of Soils for EngineeringPurposes (Unified Soil Classification
7、 System)D2488 Practice for Description and Identification of Soils(Visual-Manual Procedure)D4832 Test Method for Preparation and Testing of Con-trolled Low Strength Material (CLSM) Test CylindersD5821 Test Method for Determining the Percentage ofFractured Particles in Coarse AggregateD6103 Test Meth
8、od for Flow Consistency of ControlledLow Strength Material (CLSM) (Withdrawn 2013)33. Terminology3.1 GeneralTerminology C896 can be used for clarifica-tion of terminology in this specification.3.2 See Fig. 1.DESIGN CONSIDERATIONS4. Supporting Strength4.1 The field supporting strength of vitrified cl
9、ay pipe ismaterially affected by the methods of installation. The fieldsupporting strength of a pipe is defined as its capacity tosupport dead and live loads under actual field conditions. It isdependent upon two factors: (1) the inherent strength of thepipe and (2) the bedding of the pipe.4.2 The m
10、inimum bearing strength requirement in accor-dance with Specification C700, as determined by the 3-edge-bearing test of Test Methods C301, is a measure of the inherentstrength of the pipe.4.3 The tests used to measure bearing strength determinerelative pipe strengths but do not represent actual fiel
11、d condi-tions. Therefore, an adjustment called a load factor is intro-duced to convert minimum bearing strength to field supportingstrength. The magnitude of the load factor depends on how thepipe is bedded. The relationship is:Field supporting strength 5 minimum bearing strength 3load factor4.4 A f
12、actor of safety 1.0 and 1.5 shall be applied to thefield supporting strength to calculate a safe supporting strength.The relationship is:Safe supporting strength 5Field supporting strengthFactor of safety1This practice is under the jurisdiction of ASTM Committee C04 on VitrifiedClay Pipe and is the
13、direct responsibility of Subcommittee C04.20 on Methods ofTest and Specifications.Current edition approved May 15, 2016. Published May 2016. Originallyapproved in 1915. Last previous edition approved in 2014 as C12 14. DOI:10.1520/C0012-16.2For referenced ASTM standards, visit the ASTM website, www.
14、astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards 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.Copyright ASTM International, 100 Bar
15、r Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States15. External Loads5.1 The external loads on installed vitrified clay pipe are oftwo general types: (1) dead loads and (2) live loads.5.2 For pipes installed in trenches at a given depth, the deadload increases as the trench
16、width, measured at the top of thepipe, increases. Pipe failure may result if the design trenchwidth is exceeded. If the trench width exceeds the designwidth, a higher class of bedding, stronger pipe, or both, must beinvestigated.5.3 Live loads that act at the ground surface are partiallytransmitted
17、to the pipe. Live loads may be produced by wheelloading, construction equipment or by compactive effort.Compaction of embedment and backfill materials, beside andabove the sewer pipe, produces a temporary live load on thepipe. The magnitude of the live load from compactive effortvaries with soil typ
18、e, degree of saturation, degree of compac-tion and depth of cover over the pipe. Care must be used inselection of compaction methods so that the combined deadload and live load does not exceed the field supporting strengthof the pipe, or cause a change in its line or grade.NOTE 1For generally accept
19、ed criteria and methods for determiningloads and supporting strengths, see Gravity Sanitary Sewer Design andConstruction, Water Pollution Control Federation Manual of Practice No.FD-5, American Society of Civil EngineersManuals and Report onEngineering PracticeNo. 60.46. Bedding and Encasement6.1 Cl
20、asses of bedding and encasements for pipe in trenchesare defined herein. The load factors indicated are for conver-sion of minimum bearing strength to field supporting strength.4Available from American Society of Civil Engineers (ASCE), 1801 AlexanderBell Dr., Reston, VA 20191, http:/www.asce.org.FI
21、G. 1 TerminologyC121626.1.1 The soil groups used in each bedding class are definedin Table 1.6.1.2 The gradation for Class I and Class II soil for Class Cbedding (Fig. 3) shall have a maximum particle size of 1 in. (25mm).6.1.3 The gradation for Class I and Class II bedding materialfor Class B (Fig.
22、 4), Crushed Stone Encasement (Fig. 5), andCLSM installation (Fig. 6) shall be as follows:100 % passing a 1 in. (25 mm) sieve40-60 % passing a34 in. (19 mm) sieve0-25 % passing a38 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
23、 one fracturedface. For Class B (Fig. 4), Crushed Stone Encasement (Fig. 5),and CLSM installations (Fig. 6) where high, or changing watertables, or both, are present; Class II material shall have aminimum percentage by particle count of one fractured face-100 %, two fractured faces-85 %, and three f
24、ractured faces-65 % in accordance with Test Method D5821.6.1.6 Class I material is considered to be more stable andprovide better support than Class II material that have somerounded edges.6.1.7 All bedding material shall be shovel-sliced so thematerial fills and supports the haunch area and encases
25、 the pipeto the limits shown in the trench diagrams.6.2 Class D (Fig. 2):6.2.1 The pipe shall be placed on a firm and unyieldingtrench bottom with bell holes provided (Fig. 7).6.2.2 The initial backfill shall be either Class I, II, III, or IVhaving a maximum particle size of 1 in. (25 mm).6.2.3 The
26、load factor for Class D bedding is 1.1.6.3 Class 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 asa bedding material in a total sand environment, but may beunsuitable where high and rapidly changing water tables are
27、present in the pipe zone. Sand may also be undesirable in atrench cut by blasting or in trenches through clay type soil.Regardless of the trench condition or bedding class, themaximum load factor for sand bedding is 1.5. The beddingshall have a minimum thickness beneath the pipe of 4 in. (100mm) or
28、one sixth of the outside diameter of the pipe, whicheveris greater, and shall extend up the haunches of the pipe onesixth of the outside diameter of the pipe.6.3.2 The initial backfill shall be either Class I, II, III, or IVhaving maximum particle size of 1-12 in. (38 mm) (see Table2).6.3.3 The load
29、 factor for Class C bedding is 1.5.6.4 Class B (Fig. 4):6.4.1 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. Thebedding shall have a minimum thickness beneath the pipe of 4in. (100 mm) or one sixth of the outside diameter of the pipe,whichev
30、er is greater, and shall extend up the haunches of thepipe to the springline.6.4.2 The initial backfill shall be either Class I, II, III, or IVhaving 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 shal
31、l be bedded in Class I or Class II soil.Refer to 6.1.3, 6.1.5, and Table 2 for requirements. Thebedding shall have a minimum thickness beneath the pipe of 4in. (100 mm) or one sixth of the outside diameter of the pipe,whichever is greater, and shall extend upward to a horizontalTABLE 1 Uniform Soil
32、Groups for Pipe InstallationNOTE 1Soil Classification descriptions and symbols are in accordance with Practice D2487 and Practice 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 #2
33、00 sieve) should be treated as Class IIsoils.NOTE 4Class V soil is not suitable for use as a bedding or initial backfill material.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 symbolswit
34、h 30 % retained on #200 sieveML, CLClass V fine-grained soils, organic soilshigh compressibility silts and clays, organic soilMH, CH, OL, OH, PtC12163plane at the top of the pipe barrel. Material shall be carefullyplaced into the pipe haunches.6.5.2 Sufficient material shall be placed so that the be
35、ddingextends to a horizontal plane at the top of the pipe barrelfollowing removal of any trench sheeting or boxes.6.5.3 The initial backfill shall be either Class I, II, III, or IVhaving 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 Control
36、led Low Strength Material (Fig. 6)Controlledlow strength material (CLSM) is used as an effective materialfor the bedding of vitrified clay pipe.6.6.1 The pipe shall be bedded on Class I or Class II soil.Refer to 6.1.3, 6.1.5, and Table 2 for requirements. Thebedding shall have a minimum thickness be
37、neath the pipe of 4in. (100 mm) or one sixth of the outside diameter of the pipe,whichever is greater.6.6.2 For pipe diameters 8 to 21 in. (205 to 535 mm), CLSMshall 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 m
38、inimum of 12 in. (305 mm) on eachside of the pipe barrel (Fig. 6).6.6.3 When placed, CLSM shall have a measured flowabil-ity of 8 6 1 in. (205 6 25 mm) spread diameter as determinedby Test Method D6103.6.6.4 28-day compressive strength shall be 100 to 300 psi(0.69 to 2.07 MPa) as determined by Test
39、Method D4832.FIG. 2 Class DFIG. 3 Class CC121646.6.5 CLSM shall be directed to the top of the pipe to flowdown equally on both sides to prevent misalignment. PlaceCLSM to the top of the pipe barrel.6.6.6 The initial backfill shall be either Class I, II, III, or IVhaving a maximum particle size of 1-
40、12 in. (38 mm).6.6.7 Initial backfill shall only commence after a 500 psi(3.45 MPa) minimum penetrometer reading is achieved asdetermined by Test Method C403/C403M. The penetrometershall have a maximum load capability of 700 psi (4.83 MPa)and have a 1 in.2 1 in. (645 mm2 25 mm) long cylinder footatt
41、ached to a14 in. (6 mm) diameter pin.6.6.8 The load factor for controlled low strength material is2.8.6.7 Concrete Cradle (Fig. 8)6.7.1 The pipe shall be bedded in a cradle of reinforcedconcrete having a thickness under the barrel of at least 6 in.(150 mm) or one fourth of the outside diameter of th
42、e pipe,whichever is greater, and extending up the haunches to a heightof at least one half the outside diameter of the pipe. The cradlewidth shall be at least equal to the outside diameter of the pipeplus 4 in. (100 mm) on each side or one and one fourth timesthe outside diameter of the pipe, whiche
43、ver is greater. If thetrench width is greater than either of these dimensions,concrete may be placed to full trench width.6.7.2 The initial backfill shall be either Class I, II, III, or IVhaving a maximum particle size of 1-12 in. (38 mm).6.7.3 The load factor for Class A concrete cradle bedding is3
44、.4 for reinforced concrete with p = 0.4 %, where p is thepercentage of the area of transverse steel to the area of concreteat the bottom of the pipe barrel as shown in Fig. 8.6.8 Concrete Encasement:6.8.1 There are specific sites where concrete encasementmay be desirable. Concrete encasement shall c
45、ompletely sur-round the pipe and shall have a minimum thickness, at anyFIG. 4 Class BFIG. 5 Crushed Stone EncasementC12165point, of one fourth of the outside diameter of the pipe or 4 in.(100 mm), whichever is greater.6.8.2 The encasement shall be designed by the engineer tosuit the specific use.6.9
46、 Construction joints shall be installed in concrete cradleor concrete encasement construction. These joints shall bealigned with the face of the socket.CONSTRUCTION TECHNIQUES7. Trench Excavation7.1 Trenches shall be excavated to a width that will provideadequate working space, but not more than the
47、 maximumdesign width. Trench walls shall not be undercut.7.2 The trench walls can be sloped to reduce trench wallfailure. This sloping will not increase the load on the pipeprovided the measured trench width at top of pipe does notexceed the design trench width.7.3 Trenches, other than for Class D b
48、edding, shall beexcavated to provide space for the pipe bedding.7.4 Sheet, shore, and brace trenches, as necessary, to pre-vent caving or sliding of trench walls, to provide protection forworkmen and the pipe, and to protect adjacent structures andfacilities.7.5 Sheeting shall not be removed below t
49、he top of the pipeif the resulting slope of native soil increases the trench width tosuch an extent that the load on the pipe exceeds the safe fieldsupporting strength of the pipe and bedding system.7.6 When a movable box is used in place of sheeting orshoring, secure the installed pipe to prevent it from movingwhen the box is moved.7.7 Maintain the water level in the trench to an elevationbelow the bell of the pipe being laid. Exercise caution whenterminating the dewatering procedure to avoid disturbing thepipe installation.NOTE 2The purpose of controlling
