1、Designation:D 2434 68(Reapproved 2006)Standard Test Method forPermeability of Granular Soils(Constant Head)1This standard is issued under the fixed designation D 2434;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last r
2、evision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon(e)indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the Department of Defense.1.Scope1.1 This test method covers the determination of th
3、e coef-ficient of permeability by a constant-head method for thelaminar flow of water through granular soils.The procedure isto establish representative values of the coefficient of perme-ability of granular soils that may occur in natural deposits asplaced in embankments,or when used as base course
4、s underpavements.In order to limit consolidation influences duringtesting,this procedure is limited to disturbed granular soilscontaining not more than 10%soil passing the 75-m(No.200)sieve.1.2 This standard does not purport to address all of thesafety problems,if any,associated with its use.It is t
5、heresponsibility 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 ASTM Standards:2D 422 Test Method for Particle-Size Analysis of SoilsD 4253 Test Methods for Maximum I
6、ndex Density and UnitWeight of Soils Using a Vibratory TableD 4254 Test Methods for Minimum Index Density and UnitWeight of Soils and Calculation of Relative Density3.Fundamental Test Conditions3.1 The following ideal test conditions are prerequisites forthe laminar flow of water through granular so
7、ils underconstant-head conditions:3.1.1 Continuity of flow with no soil volume change duringa test,3.1.2 Flow with the soil voids saturated with water and noair bubbles in the soil voids,3.1.3 Flow in the steady state with no changes in hydraulicgradient,and3.1.4 Direct proportionality of velocity o
8、f flow with hydrau-lic gradients below certain values,at which turbulent flowstarts.3.2 All other types of flow involving partial saturation ofsoil voids,turbulent flow,and unsteady state of flow aretransient in character and yield variable and time-dependentcoefficients of permeability;therefore,th
9、ey require special testconditions and procedures.4.Apparatus4.1 Permeameters,as shown in Fig.1,shall have specimencylinders with minimum diameters approximately 8 or 12times the maximum particle size in accordance with Table 1.The permeameter should be fitted with:(1)a porous disk orsuitable reinfor
10、ced screen at the bottom with a permeabilitygreater than that of the soil specimen,but with openingssuffciently small(not larger than 10%finer size)to preventmovement of particles;(2)manometer outlets for measuringthe loss of head,h,over a length,l,equivalent to at least thediameter of the cylinder;
11、(3)a porous disk or suitablereinforced screen with a spring attached to the top,or anyother device,for applying a light spring pressure of 22 to 45-N(5 to 10-lbf)total load,when the top plate is attached in place.This will hold the placement density and volume of soil withoutsignificant change durin
12、g the saturation of the specimen andthe permeability testing to satisfy the requirement prescribed in3.1.1.4.2 Constant-Head Filter Tank,as shown in Fig.1,tosupply water and to remove most of the air from tap water,fitted with suitable control valves to maintain conditionsdescribed in 3.1.2.NOTE1De-
13、aired water may be used if preferred.1This test method is under the jurisdiction ofASTM Committee D18 on Soil andRock and is the direct responsibility of Subcommittee D18.04 on HydrologicProperties and Hydraulic Barriers.Current edition approved Feb.1,2006.Published March 2006.Originallyapproved in
14、1965.Last previous edition approved in 2000 as D 243468(2000).2For referenced ASTM standards,visit the ASTM website,www.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.1Cop
15、yright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959,United States.4.3 Large Funnels,fitted with special cylindrical spouts 25mm(1 in.)in diameter for 9.5-mm(38-in.)maximum sizeparticles and 13 mm(12in.)in diameter for 2.00-mm(No.10)maximum size particles.The l
16、ength of the spout should begreater than the full length of the permeability chamberatleast 150 mm(6 in.).4.4 SpecimenCompactionEquipment2Compactionequipment as deemed desirable may be used.The following aresuggested:a vibrating tamper fitted with a tamping foot 51 mm(2 in.)in diameter;a sliding tamper with a tamping foot 51 mm(2 in.)in diameter,and a rod for sliding weights of 100 g(0.25lb)(for sands)to 1 kg(2.25 lb)(for soils with a large gravelcontent),having an adjustable height of drop to 1
