1、Designation: D 5195 08Standard Test Method forDensity of Soil and Rock In-Place at Depths Below Surfaceby Nuclear Methods1This standard is issued under the fixed designation D 5195; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, t
2、he 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. Scope*1.1 This test method covers the calculation of the density ofsoil and rock by the attenuation of gamma radiati
3、on, where thegamma source and the gamma detector are placed at thedesired depth in a bored hole lined by an access tube.1.1.1 For limitations see Section 5 on Interference.1.2 The density, in mass per unit volume of the materialunder test, is calculated by comparing the detected rate ofgamma radiati
4、on with previously established calibration data(see Annex A1).1.3 A precision statement has not been developed for thisstandard at this time. Therefore, this standard should not beused for acceptance or rejection of a material for purchasignpurposes unless correlated to other accepted ASTM standards
5、.1.4 The values stated in SI units are regarded as thestandard. The inch-pound units given in parentheses are forinformation only and may be approximate.1.5 All observed and calculated values shall conform to theguide for significant digits and rounding established in PracticeD 6026.1.5.1 The proced
6、ures used to specify how data are collected,recorded, and calculated in this standard are regarded as theindustry standard. In addition, they are representative of thesignificant digits that should generally be retained. The proce-dures used do not consider material variation, purpose forobtaining t
7、he data, special purpose studies, or any consider-ations for the users objectives; and it is common practice toincrease or reduce significant digits of reported data to becommensurate with these considerations. It is beyond the scopeof this standard to consider significant digits used in analysismet
8、hods for engineering design.1.6 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 health practices and determine the applica-bility of regulatory limitations
9、prior to use. Specific precau-tionary statements are given in Section 7, “Hazards.”2. Referenced Documents2.1 ASTM Standards:2D 653 Terminology Relating to Soil, Rock, and ContainedFluids3D 1452 Practice for Soil Investigation and Sampling byAuger BoringsD 1587 Practice for Thin-Walled Tube Sampling
10、 of Soilsfor Geotechnical PurposesD2113 Practice for Rock Core Drilling and Sampling ofRock for Site InvestigationD 2216 Test Methods for Laboratory Determination of Wa-ter (Moisture) Content of Soil and Rock by MassD 2937 Test Method for Density of Soil in Place by theDrive-Cylinder MethodD 3740 Pr
11、actice for Minimum Requirements for AgenciesEngaged in Testing and/or Inspection of Soil and Rock asUsed in Engineering Design and ConstructionD 4428/D 4428M Test Methods for Crosshole Seismic Test-ingD 5220 Test Method for Water Content of Soil and RockIn-Place by the Neutron Depth Probe MethodD 60
12、26 Practice for Using Significant Digits in Geotechni-cal DataD 6938 Test Method for In-Place Density and Water Con-tent of Soil and Soil-Aggregate by Nuclear Methods(Shallow Depth)3. Terminology3.1 See Terminology D 653 for general definitions.3.2 Definitions of Terms Specific to This Standard:3.2.
13、1 wet densitysame as bulk density (as defined inTerminology D 653); the total mass (solids plus water) per totalvolume.3.2.2 gamma (radiation) sourcea sealed source of radio-active material that emits gamma radiation as it decays.3.2.3 gamma detectora device to detect and measuregamma radiation.1Thi
14、s test method is under the jurisdiction ofASTM Committee D18 on Soil andRock and is the direct responsibility of Subcommittee D18.08 on Special andConstruction Control Tests.Current edition approved Sept. 1, 2008. Published September 2008. Originallyapproved in 1991. Last previous edition approved i
15、n 2002 as D 5195 02.2For 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.3Replace with continuous flight and hollo
16、wstream methods when available.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.3.2.4 Compton scatteringthe interaction between agamma ray (photon) and an orbital elect
17、ron where the gammaray loses energy and rebounds in a different direction.3.2.5 water contentthe ratio of the mass of water con-tained in the pore spaces of soil or soil-aggregate, to the solidmass of particles in that material, expressed as a percentage(this is sometimes referred to in some scienti
18、fic fields asgravimetric water content to differentiate it from volumetricwater content).3.2.6 volumetric water contentthe volume of water as apercent of the total volume of soil or rock material.4. Significance and Use4.1 This test method is useful as a rapid, nondestructivetechnique for the calcul
19、ation of the in-place density of soil androck at desired depths below the surface as opposed to surfacemeasurements in accordance with Test Method D 6938.4.2 This test method is useful for informational and researchpurposes. It should only be used for quality control andacceptance testing when corre
20、lated to other accepted methodssuch as Test Method D 2937.4.3 The non-destructive nature of the test method allowsrepetitive measurements to be made at a single test location forstatistical analysis and to monitor changes over time.4.4 The fundamental assumptions inherent in this testmethod are that
21、 Compton scattering and photoelectric absorp-tion are the dominant interactions of the gamma rays with thematerial under test.NOTE 1The quality of the result produced by this standard testmethod is dependent on the competence of the personnel performing it,and the suitability of the equipment and fa
22、cilities used.Agencies that meetthe criteria of Practice D 3740 are generally considered capable ofcompetent and objective testing/sampling/inspection, and the like. Usersof this test method are cautioned that compliance with Practice D 3740does not in itself assure reliable results. Reliable result
23、s depend on manyfactors; Practice D 3740 provides a means of evaluating some of thosefactors.5. Interferences5.1 The chemical composition of the sample may affect themeasurement and adjustments may be necessary. Some ele-ments with atomic numbers greater than 20 such as iron (Fe) orother heavy metal
24、s may cause measurements higher than thetrue density value.5.2 The sample heterogeneity affects the measurements.This test method also exhibits spatial bias in that it is moresensitive to material closest to the access tube.5.2.1 Voids around the access tube can affect the measure-ment (see 9.1.2.1)
25、.5.3 The sample volume is approximately 0.028 m3(0.8 ft3).The actual sample volume is indeterminate and varies with theapparatus and the density of the material. In general, the greaterthe density the smaller the volume.6. Apparatus (See Fig. 1)6.1 The apparatus shall consist of a nuclear instrument
26、capable of measuring density of materials at various depthsbelow the surface and contain the following:6.1.1 Sealed Source of High Energy Gamma Radiation,such as cesium-137, cobalt-60, or radium-226.6.1.2 Gamma DetectorAny type of gamma detector suchas a Geiger-Mueller tube.6.1.3 Suitable Timed Scal
27、er and Power Source.6.2 Cylindrical ProbeThe apparatus shall be equippedwith a cylindrical probe, containing the gamma source anddetector, connected by a cable of sufficient design and length,that is capable of being lowered down a cased hole to desiredtest depths.6.3 Reference StandardThe apparatus
28、 shall be equippedwith a reference standard, a fixed shape of dense material usedfor checking apparatus operation and to establish conditions fora reproducible reference count rate. It may also serve as aradiation shield.6.4 Apparatus PrecisionSee Annex A3 for the precisionof the apparatus.6.5 Acces
29、sories:6.5.1 Access TubingThe access tubing (casing) is requiredfor all access holes in nonlithified materials (soils and poorlyconsolidated rock) that cannot maintain constant boreholediameter with repeated measurements. If access tubing isrequired it must be of a material such as aluminum, steel,
30、orpolyvinyl chloride, having an interior diameter large enough topermit probe access without binding, and an exterior diameteras small as possible to provide close proximity of the materialunder test. The same type of tubing must be used in the field asis used in calibration.6.5.2 Hand Auger or Powe
31、r Drilling Equipment, that can beused to establish the access hole. Any drilling equipment thatprovides a suitable clean open hole for installation of accesstubing and insertion of the probe that ensures the measure-ments are performed on undisturbed soil and rock whilemaintaining constant borehole
32、diameter shall be acceptable.The type of equipment and methods of advancing the accesshole should be reported.7. Hazards7.1 These gauges utilize radioactive materials that may behazardous to the health of the users unless proper precautionsare taken. Users of these gauges must become familiar withap
33、plicable safety procedures and government regulations.7.2 Effective user instructions, together with routine safetyprocedures and knowledge of and compliance with RegulatoryRequirements, are a mandatory part of the operation andstorage of these gauges.FIG. 1 Schematic Diagram: Depth Density by Nucle
34、ar MethodD51950828. Calibration, Standardization, and Reference Check8.1 Calibrate the instrument in accordance with Annex A1.8.2 Adjust the calibration in accordance with Annex A2 ifadjustments are necessary.8.3 Standardization and Reference Check:8.3.1 Nuclear density gauges are subject to long-te
35、rm agingof the radioactive sources, which may change the relationshipbetween count rates and the material density. To correct for thisaging effect, gauges are calibrated as a ratio of the measure-ment count rate to a count rate made on a reference standard.8.3.2 Standardization of the gauge shall be
36、 performed at thestart of each days use, and a record of these data should beretained for the amount of time required to ensure compliancewith either Section 8.3.4 or 8.3.5, whichever is applicable.Perform the standardization with the gauge far enough awayfrom other apparatus containing radioactive
37、sources to preventinterference due to radiation from the other apparatus. Inaddition, perform the standardization far enough away fromlarge masses or other items which can affect the referencecount rates due to reflections from these masses or items.NOTE 2Separation of nuclear gauges by a distance o
38、f 9 m (30 ft) fromone another has typically proven sufficient in preventing radiation fromone gauge from being detected by another gauge and potentially causingan incorrect standardization count. This separation can be reduced by theproper use of shielding. With regards to reflections from large mas
39、ses orother items potentially causing incorrect standardization counts, a sepa-ration of1m(3ft)between the gauge and the mass or item in question hastypically proven sufficient to prevent such reflections from influencing thestandardization counts.8.3.3 Turn on the gauge and allow for stabilization
40、accord-ing to the manufacturers recommendations.8.3.4 Using the reference standard, take at least four repeti-tive readings at the normal measurement period and obtain themean. If available on the gauge, one measurement at four ormore times the normal measurement period is acceptable. Thisconstitute
41、s one standardization check. Use the procedure rec-ommended by the gauge manufacturer to establish the compli-ance of the standard measurement to the accepted range.Without specific recommendations from the gauge manufac-turer, use the procedure in 8.3.5.8.3.5 If the value of the current standardiza
42、tion count isoutside the limits set by Eq 1, repeat the standardization check.If the second standardization check satisfies Eq 1, the gauge isconsidered in satisfactory operating condition.0.99Nc!eln2!tT1/2 #N0#1.01Nc!eln2!tT1/2 (1)where:T1/2= the half-life of the isotope that is used for thedensity
43、 or moisture determination in the gauge. Forexample,137Cs, the isotope most commonly usedfor density determination in these gauges, T1/2is 11023 days,Nc= the standardization count acquired at the time of thelast calibration or verification,N0= the current standardization count,t = the time that has
44、elapsed between the currentstandardization test and the date of the last calibra-tion or verification. The units selected for t and T1/2should be consistent, that is, if T1/2is expressed indays, then t should also be expressed in days,ln( ) = the natural logarithm function, ande = the inverse of the
45、 natural logarithm function, equalto 2.71828182845904.8.3.6 ExampleA nuclear gauge containing a137Cs sourcefor density determination (half-life = 11 023 days) is calibratedon March 1 of a specific year. At the time of calibration, thedensity standard count was 2800 counts per minute (prescaled).Acco
46、rding to Eq 1, what is the allowed range of standardcounts for November 1 of the same year? For this example, atotal of 245 days have elapsed between the date of calibrationor verification (March 1) and the date of the gauge standard-ization (November 1).Therefore:t = 245 daysT1/2= 11 023 daysNc= 28
47、00 countsAccording to Eq 1, therefore, the lower limit for the densitystandard count taken on November 1, denoted by N0,is0.99Nc!eln2!tT1/2 5 0.992800!eln2! 24511 023 5 2772e0.015415 2730 countsLikewise, the upper limit for the density standard count takenon November 1, denoted by N0,is1.01Nc!eln2!t
48、T1/2 5 1.012800!eln2! 24511 023 5 2828e0.015415 2785 countsTherefore, the density standard count acquired on November 1should lie somewhere between 2730 and 2785 counts, or 2730# N0# 2785.8.3.7 If for any reason the measured density becomessuspect during the days use, perform another standardization
49、check.9. Procedure9.1 Installation of Access Tubing (Casing):9.1.1 Drill the access tube hole and install access tube in amanner dependent upon the material to be tested, the depth tobe tested, and the available drilling equipment.9.1.2 The access hole must be clear enough to allowinstalling the tube yet must provide a snug fit. Voids along sidethe tube will cause erroneous readings.9.1.2.1 If voids are suspected to be caused by the drillingprocess they can be grouted using the procedures in TestMethod D 4428/D 4428M. The only method to
