1、Designation: F449 02 (Reapproved 2014)F449 16Standard Practice forSubsurface Installation of Corrugated Polyethylene Pipe forAgricultural Drainage or Water Table Control1This standard is issued under the fixed designation F449; the number immediately following the designation indicates the year of o
2、riginaladoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.Asuperscriptepsilon () indicates an editorial change since the last revision or reapproval.1. Scope Scope*1.1 This practice is recommended for and limited to gravity fl
3、ow subsurface drainage systems or water table control, but notrecommended for sanitary or storm sewer applications. Procedures are outlined to minimize pipe deflection or structural damageduring and after the installation process. These installation procedures are in accordance with “flexible condui
4、t” principles.1.2 This practice applies to all agricultural subsurface drainage or water table control installations using SpecificationF405F667, F667F2648, or other plastic pipe.1.3 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematica
5、lconversions to SI units that are provided for information only and are not considered standard.1.4 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 p
6、ractices and determine the applicability of regulatorylimitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D1600 Terminology for Abbreviated Terms Relating to PlasticsD2412 Test Method for Determination of External Loading Characteristics of Plastic Pipe by Parallel-Plate LoadingF405
7、Specification for Corrugated Polyethylene (PE) Pipe and Fittings (Withdrawn 2015)3F412 Terminology Relating to Plastic Piping SystemsF667 Specification for 3 through 24 in. Corrugated Polyethylene Pipe and FittingsF2648 Specification for 2 to 60 inch 50 to 1500 mm Annular Corrugated Profile Wall Pol
8、yethylene (PE) Pipe and Fittings forLand Drainage Applications3. Terminology3.1 Definitions are in accordance with Terminology F412 and abbreviations are in accordance with Terminology D1600, unlessotherwise specified.3.2 backfillmaterials used to fill the trench following installation of the pipe a
9、nd bedding.3.3 beddingmaterial which provides stable bottom support for the pipe including the trench bottom groove support angle orselect material placed around the pipe, and envelope or filter materials where used during installation.3.4 blindingthe placement of soil, bedding material over and on
10、the sides of the pipe or envelope to ensure proper grade,alignment, support, and protection of pipe during backfilling and after installation.3.5 boot (also shield)the protecting apparatus linked to the rear of the installation machine in a manner which allowsplacement of the pipe on the trench bott
11、om, protection of the workman, or placement of envelope or filter material, or both.3.6 cradlea prefabricated rigid structure designed to provide trench bottom support for the pipe when soil support isinadequate.1 This practice is under the jurisdiction of ASTM Committee F17 on Plastic Piping System
12、s and is the direct responsibility of Subcommittee F17.65 on Land Drainage.Current edition approved March 1, 2014Feb. 15, 2016. Published September 2014March 2016. Originally approved in 1976. Last previous edition approved in 20082014as F449 02(2008).(2014). DOI: 10.1520/F0449-02R14.10.1520/F0449-1
13、6.2 For referencedASTM standards, visit theASTM website, 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.This document is not an ASTM standard and is intended only
14、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 all cases only the current version
15、of the standard as published by ASTM is to be considered the official document.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States13.7 envelopeporous material placed around
16、the pipe to provide bedding, improve the flow of ground water into the drain, orfunction as a filter.3.8 filteran envelope of natural or synthetic materials placed completely around a drain to permit free water movement intothe drain, provide stabilizing support at the soil-filter interface, and res
17、trict movement of silt and sand into the drain.3.9 gradethe slope of the pipe invert.3.10 groove support angleangle between the radii of the pipe at points of contact with the formed groove of undisturbed soilor a cradle.3.11 mineral soilssoil containing (1) less than 30 % organic matter by weight p
18、rovided the mineral fraction is 60 % or moreclay, or (2) less than 20 % organic matter by weight provided the mineral fraction has no clay, or (3) less than a proportional contentof organic matter between 20 and 30 % if the clay content of the mineral fraction is between 0 and 60 %.3.12 natural gran
19、ular envelopean envelope of granular material, usually highly permeable well-graded sand and gravel.3.13 organic soilsoil containing (1) 30 % or more organic matter provided the mineral fraction is 60 % or more clay, or (2) 20 % or more organic matter provided the mineral fraction has no clay, or (3
20、) a proportional content of organic matter between20 and 30 % if the clay content of mineral fraction is between 0 and 60 %. (It is a general rule that a soil is classed as an organicsoil (histosol) either if more than one half of upper 32 in. (80 mm) of soil is organic or if organic soil material o
21、f any thicknessrests on rock or on fragmental material having voids filled with organic material.)3.14 pipe stiffnessforce per unit length, per unit deflection as defined in Test Method D2412.3.15 power feedermechanism that applies force to the pipe as it passes through the boot or shield to reduce
22、stretch duringinstallation.3.16 pre-rippingthe practice of making a pass with the plow without installing pipe to locate rocks and to reduce draft.3.17 semi-circular groovea rounded trench bottom in native insitu soil that conforms to the outside diameter from the invertto the springline of the pipe
23、.3.18 start holea trench sufficiently long and wide to allow working room for placing the boot or shield, blade or cuttingmechanism on grade to start the trench and to install connections or pipe.3.18.1 DiscussionStart holes are usually dug with a backhoe with a flat-bottom trench.3.19 stretchthe in
24、crease in length of the pipe caused by tension forces during installation. It is expressed as a percent increaseof the length prior to installation. Stretch differs from elongation in that elongation is a material test and stretch is an installationtest.3.20 synthetic envelopean envelope made of syn
25、thetic geotextiles, usually thin synthetic fabrics or thicker fibrous material,or both, often selected to function as a filter.3.21 trench depththe depth of the trench measured from the bottom of the pipe.3.22 trench widththe width of the trench measured at the top of the pipe.3.23 Fig. 1 illustrate
26、s the terms bedding, vertical deflection, backfill material, cover, groove support angle, horizontal deflection,trench width, and trench depth.Fig. 2a and b illustrates various support grooves or trench bottom shapes.Fig. 3 illustrates envelope and filter.Fig. 4 illustrates rodent protection devices
27、.Fig. 5 illustrates boot or shield.4. General Requirements4.1 BurialThe maximum and minimum burial depth are affected by the following factors, groove support angle or shape ofthe trench bottom, bedding, blinding backfill soil density, envelope density, envelope placement, pipe stiffness, the live l
28、oadexpected, desired water table depth, and width of trench.4.1.1 Minimum Depth:4.1.1.1 Mineral SoilsThe minimum recommended cover needed to protect the pipe from crushing under live loads is 2 ft (0.6m). Granular bedding or special construction techniques may be used to reduce the cover. The time f
29、or consolidation of backfillmay be a factor (see 8.1). The minimum cover may have limiting factors other than crushing such as clearance for subsoiling andutility crossing4.1.1.2 Organic SoilsSubsurface drains should be installed in these soils only after initial subsidence has occurred. To producei
30、nitial subsidence open ditches should be constructed in deep organic soils to carry off free water, and the area should be allowedto stand or be partially cultivated for a period of 3 to 5 years before installing pipe. The recommended minimum cover for the pipeF449 162in organic soils is 2.5 ft (0.7
31、 m). If water level controls are not provided in the drainage system to hold subsidence to a minimum,the depth of cover should be increased to 3 ft (0.9 m).NOTE 1These minimum depths are recommended to prevent crushing of the pipe by normal agricultural vehicle loads. Other drainage factors suchas t
32、hose encountered with salinity control in arid irrigated lands may require minimum depths of 6 ft (1.8 m).4.1.2 Maximum DepthThe maximum burial depth is influenced by such factors as degree of compaction, type of bedding,support from the trench bottom, trench width, size of pipe, pipe stiffness, wei
33、ght of backfill, and live loads imposed. Without anengineering design, maximum buried depths should be limited to those listed in Table 1 or Table 2. For installation at depths greaterthan those listed in Table 1 or Table 2, specifications of and engineering design should be followed.4.1.3 Trench Wi
34、dthIncreasing the trench width increases the soil load on the pipe. Side clearances of more than 150 mm (6in.) on each side should only be used with an engineering design and special construction (see Table 1). TrenchFor Table 1 designs,the trench width must be at least 50 mm (2 in.) wider than the
35、pipe on each side for plow installation and 75 to 150 mm (3 to 6in.) on each side for open trench installation to allow sufficient bedding to support the pipe. If fine material cannot be placedFIG. 1 Terminology for Installation of Plastic Drain PipeFIG. 2 a Support GroovesF449 163alongside and over
36、 the pipe, a wider trench should be considered or special bedding material supplied. For Table 2 designs, amaximum and minimum trench width is specified to limit excessive deflection and allow a larger amount of soil arching to reducethe load on the pipe. The tile boot or trench box used to construc
37、t the semi-circular groove shall conform as closely as possibleto pipe OD and shall be within 1% or 12 in. (12 mm), whichever is greater, of the pipe OD. The trench width requirements onlypertain to the vertical distance from the springline to the top of the pipe. It is permissible for the trench wi
38、dth above the top ofthe pipe to slope to the natural angle of repose of the soil.NOTE 2A narrow trench width will result in a greater transfer of loads to the sidefill materials. A semi-circular groove installation in insitu soilsconforming to the outer diameter of the pipe minimizes the impact of p
39、oor compaction or installation techniques and provides very good bedding supportin addition to reduced dead loads on the pipe.4.2 Design ItemsIt is particularly important that blinding, bedding, or envelope material be placed as the pipe is installed, toensure uniform continuous support, so that the
40、 bedding, blinding, or envelope material can provide lateral restraint against pipedeflection as the backfill settles on the bedding, blinding, or envelope material.4.3 EnvelopesMust be designed to provide adequate support for the pipe, improve the flow of ground water into the pipe, andin some inst
41、allations, filter flow into the pipe.4.3.1 Natural Granular EnvelopesMinimum thickness of 75 mm (3 in.) around the pipe.4.3.2 Synthetic EnvelopesBlinding or bedding is needed to support and hold the envelope and pipe in place.FIG. 2 b Semi-Circular Trench Groove (continued)FIG. 3 Pipe Encased in Bed
42、ding for Support (left) and Pipe Encased in Sand and Gravel Envelope Designed as Filter (right)F449 1644.4 FiltersAre required when ground water can develop velocities sufficient to move sand or silt, or both, into the drain. Filtersmust be able to restrict the movement of these particles into the p
43、ipe so that the hydraulic capacity of the pipe is maintained.4.4.1 Granular FiltersDesign of a graded sand and fine gravel filter should match the gradation of the specific soil followingcriteria developed by the Natural Resource Conservation Service, the U.S. Bureau of Reclamation, or the U.S. Army
44、 Corps ofEngineers.4.4.2 Synthetic FiltersThin synthetic fabric material or geotextiles may be used where bedding, soil, and hydraulic conditionspermit. The openings in synthetic filters must be compatible with the soil that surrounds the drain to prevent excessive movementof soil that otherwise cou
45、ld plug the drain or filter (see 5.3).NOTE 3These filters must be specified to be compatible with the soil type that encompasses the conduit since protective filters can plug and decreasethe inflow capability. Where fiberglass filter material is used, it shall be manufactured from borosilicate-type
46、glass and the manufacturer shall certify thatit is suitable for underground use. The fibers should be of variable size, with some larger fibers intertwined in the mat in a random manner.NOTE 4Vegetative filter material such as straw, hay, corn-cobs, woodchips, sawdust, and coconut fiber are not reco
47、mmended for use with flexibleconduits because such conduits depend on the development of lateral support and these soft materials may not provide the necessary lateral support.FIG. 4 Suggested Methods of Providing Rodent Protection for Outlet PipesF449 1654.5 GradeShall be as specified in the plan o
48、r guide. Deviations greater than the following shall not be allowed. Verticaldeviations of more than 0.1 ft (30.5 mm) in 10 ft (3.05 m). Negative grade that would fill the pipe more than 10 %. Due to thespeed of installation with the plow, automatic grade control is recommended. The pipe feeding sys
49、tem shall hold the pipe in placein the bottom of the trench until secured by the bedding, blinding, or envelope material.4.6 Material RequirementsPipe and fittings shall meet the requirements of the applicable ASTM standards referenced inSection 2, Table 1and , and Table 12.NOTE 1This boot design has 60 inclined rear surface for transporting blinding material to the subsurface drain pipe and minimum bend radius forpipe.FIG. 5 Example Boot DesignTABLE 1 Maximum Trench Depths for Pipe Buried in Loose,Fine-Textured Soils, ft (m)ANOTE
