1、Designation:D675808Standard Test Method forMeasuring Stiffness and Apparent Modulus of Soil and Soil-Aggregate In-Place by Electro-Mechanical Method1This standard is issued under the fixed designation D6758;the number immediately following the designation indicates the year oforiginal adoption or,in
2、 the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This test method covers the measurement by electro-mechanical means of the in-place stiff
3、ness of soil or soil-aggregate mixtures so as to determine a Youngs modulusbased on certain assumptions.The apparatus and procedureprovide a fairly rapid means of testing so as to minimizeinterference and delay of construction.The test procedure isintended for evaluating the stiffness or modulus of
4、materialsused in earthworks and roadworks.Rapid in-place stiffnesstesting supports U.S.federal and state efforts to specify thein-place performance of construction materials based on modu-lus.Results obtained from this method are applicable to theevaluation of granular cohesionless materials.They ar
5、e alsoapplicable to the evaluation of silty and clayey materials withmore than 20%fines that are not subject to a change inmoisture content.If the silty and clayey material experiences achange in moisture content,then moisture content shall betaken into account if the results of this method are to b
6、eapplicable.The stiffness measured with this method is influ-enced by boundary conditions,specifically the support offeredby underlying layers as well as the thickness and modulus ofthe layer being tested.Since this method approximates thelayer(s)being evaluated as a half-space,then the modulusmeasu
7、red is also approximate.1.2 The stiffness,in force per unit displacement,is deter-mined by imparting a small measured force to the surface ofthe ground,measuring the resulting surface velocity andcalculating the stiffness.This is done over a frequency rangeand the results are averaged.1.3 The values
8、 stated in SI units are to be regarded as thestandard.The inch-pound units equivalents may be approxi-mate.1.4 This standard 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
9、health practices and determine the applica-bility of regulatory limitations prior to use.NOTE1Notwithstanding the statements on precision and bias con-tained in this test method;the precision of this test method is dependenton the competence of the personnel performing it,and the suitability of thee
10、quipment and facilities used.Agencies that meet the criteria of PracticeD3740 are generally considered capable of competent and objectivetesting.Users of this test method are cautioned that compliance withPractice D3740 does not in itself assure reliable testing.Reliable testingdepends on many facto
11、rs;Practice D3740 provides a means of evaluatingsome of those factors.2.Referenced Documents2.1 ASTM Standards:2D653 Terminology Relating to Soil,Rock,and ContainedFluidsD698 Test Methods for Laboratory Compaction Character-istics of Soil Using Standard Effort(12 400 ft-lbf/ft3(600kN-m/m3)D1557 Test
12、 Methods for Laboratory Compaction Character-istics of Soil Using Modified Effort(56,000 ft-lbf/ft3(2,700 kN-m/m3)D2216 Test Methods for Laboratory Determination of Water(Moisture)Content of Soil and Rock by MassD3740 Practice for Minimum Requirements for AgenciesEngaged in Testing and/or Inspection
13、 of Soil and Rock asUsed in Engineering Design and ConstructionD4220 Practices for Preserving and Transporting SoilSamplesD4643 Test Method for Determination of Water(Moisture)Content of Soil by Microwave Oven HeatingD4944 Test Method for Field Determination of Water(Mois-ture)Content of Soil by the
14、 Calcium Carbide Gas PressureTesterD4959 Test Method for Determination of Water(Moisture)Content of Soil By Direct Heating3.Terminology3.1 Definitions:1This test method is under the jurisdiction ofASTM Committee D18 on Soil andRock and is the direct responsibility of Subcommittee D18.08 on Special a
15、ndConstruction Control Tests.Current edition approved Jan.1,2008.Published February 2008.Originallyapproved in 2002.Last previous edition approved in 2002 as D6758 02.DOI:10.1520/D6758-08.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceast
16、m.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 3.1.1 For common definitions of terms in this standard,referto Terminology D653.3.1.2 stiffness,nthe ratio of change of force to the corre-sponding change in translational deflection of an elasticelement.D6533.1.3 Youngs modulus,nthe ratio of the increase in stresson
