1、Designation:D4718/D4718M15Standard Practice forCorrection of Unit Weight and Water Content for SoilsContaining Oversize Particles1This standard is issued under the fixed designation D4718/D4718M;the number immediately following the designation indicates theyear of original adoption or,in the case of
2、 revision,the year of last revision.A number in parentheses indicates the year of lastreapproval.A superscript 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 Defense.1.Scope*1.1 This practice p
3、resents a procedure for calculating theunit weights and water contents of soils containing oversizeparticles when the data are known for the soil fraction with theoversize particles removed.1.2 This practice also can be used to calculate the unitweights and water contents of soil fractions when the
4、data areknown for the total soil sample containing oversize particles.1.3 This practice is based on tests performed on soils andsoil-rock mixtures in which the portion considered oversize isthat fraction of the material retained on the 4.75-mm No.4sieve.Based on these tests,this practice is applicab
5、le to soilsand soil-rock mixtures in which up to 40%of the material isretained on the 4.75-mm No.4 sieve.The practice also isconsidered valid when the oversize fraction is that portionretained on some other sieve,but the limiting percentage ofoversize particles for which the correction is valid may
6、belower.However,the practice is considered valid for materialshaving up to 30%oversize particles when the oversize fractionis that portion retained on the 19-mm 34-in.sieve.1.4 The factor controlling the maximum permissible per-centage of oversize particles is whether interference betweenthe oversiz
7、e particles affects the unit weight of the finerfraction.For some gradations,this interference may begin tooccur at lower percentages of oversize particles,so the limitingpercentage must be lower for these materials to avoid inaccu-racies in the computed correction.The person or agency usingthis pra
8、ctice shall determine whether a lower percentage is tobe used.1.5 This practice may be applied to soils with any percent-age of oversize particles subject to the limitations given in 1.3and 1.4.However,the correction may not be of practicalsignificance for soils with only small percentages of oversi
9、zeparticles.The person or agency specifying this practice shallspecify a minimum percentage of oversize particles belowwhich the practice need not be applied.If a minimum percent-age is not specified,5%shall be used.1.6 This practice may not be applicable to soil-rock mix-tures which degrade under f
10、ield compaction.1.7 UnitsThe values stated in either SI Units or inch-pound units are to be regarded separately as standard.Thevalues stated in each system may not be exact equivalents;therefore,each system shall be used independently of the other.Combining values from the two systems may result in
11、non-conformance with the standard.1.7.1 It is common practice in the engineering profession toconcurrently use pounds to represent both a unit of mass(lbm)and a force(lbf).This implicitly combines two separatesystems of units;that is,the absolute system and the gravita-tional system.It is scientific
12、ally undesirable to combine the useof two separate sets of inch-pound units within a singlestandard.This standard has been written using the gravitationalsystem of units when dealing with the inch-pound system.Inthis system,the pound(lbf)represents a unit of force(weight).However,the use of balances
13、 or scales recording pounds ofmass(lbm)or the recording of density in lbm/ft3shall not beregarded as a non conformance with this standard.NOTE1Sieve size is identified by its standard designation in Speci-fication E11.The alternative designation given in brackets is for informa-tion only and does no
14、t represent a different standard sieve size.1.8 All observed and calculated values shall conform to theguidelines for significant digits and rounding established inPractice D6026.1.8.1 The procedures used to specify how data are collected/recorded and calculated in this standard are regarded as thei
15、ndustry standard.In addition,they are representative of thesignificant digits that generally should be retained.The proce-dures used do not consider material variation,purpose forobtaining data,special purpose studies,or any considerationsfor the users objectives;and it is common practice to increas
16、eor reduce significant digits of reported data to commensuratewith these considerations.It is beyond the scope of these test1This practice is under the jurisdiction of ASTM Committee D18 on Soil andRockand is the direct responsibility of Subcommittee D18.03 on Texture,Plasticityand Density Characteristics of Soils.Current edition approved Dec.15,2015.Published January 2016.Originallyapproved in 1987.Last previous edition approved in 2007 as D4718 87(2007).DOI:10.1520/D4718_D4718M-15.*A Summary o
