1、Designation: D5195 08D5195 14Standard Test Method forDensity of Soil and Rock In-Place at Depths Below Surfaceby Nuclear Methods1This standard is issued under the fixed designation D5195; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revis
2、ion, 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. Scope*1.1 This test method covers the calculation of the density of soil and rock by the attenuation of gamma
3、radiation, where thegamma source and the gamma detector are placed at the desired 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 material under test, is calculated by comparing the detected rate of gam
4、maradiation with previously established calibration data (see Annex A1).1.3 A precision statement has not been developed for this standard at this time. Therefore, this standard should not be used foracceptance or rejection of a material for purchasignpurchasing purposes unless correlated to other a
5、ccepted ASTM standards.1.4 UnitsThe values stated in SI units are regarded as the standard. The inch-pound units given in parentheses are forinformation only and may be approximate.1.5 All observed and calculated values shall conform to the guide for significant digits and rounding established in Pr
6、acticeD6026.1.5.1 The procedures used to specify how data are collected, recorded, and calculated in this standard are regarded as theindustry standard. In addition, they are representative of the significant digits that should generally be retained. The proceduresused do not consider material varia
7、tion, purpose for obtaining the data, special purpose studies, or any considerations for the usersobjectives; and it is common practice to increase or reduce significant digits of reported data to be commensurate with theseconsiderations. It is beyond the scope of this standard to consider significa
8、nt digits used in analysis methods for engineering design.1.6 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 practices and determine the applicabili
9、ty of regulatorylimitations prior to use. Specific precautionary statements are given in Section 7, “Hazards.”2. Referenced Documents2.1 ASTM Standards:2D653 Terminology Relating to Soil, Rock, and Contained FluidsD1452 Practice for Soil Exploration and Sampling by Auger Borings3D1587 Practice for T
10、hin-Walled Tube Sampling of Soils for Geotechnical PurposesD2113 Practice for Rock Core Drilling and Sampling of Rock for Site InvestigationD2216 Test Methods for Laboratory Determination of Water (Moisture) Content of Soil and Rock by MassD2937 Test Method for Density of Soil in Place by the Drive-
11、Cylinder MethodD3740 Practice for Minimum Requirements for Agencies Engaged in Testing and/or Inspection of Soil and Rock as Used inEngineering Design and ConstructionD4428/D4428M Test Methods for Crosshole Seismic TestingD5220 Test Method for Water Mass per Unit Volume of Soil and Rock In-Place by
12、the Neutron Depth Probe MethodD6026 Practice for Using Significant Digits in Geotechnical Data1 This test method is under the jurisdiction ofASTM Committee D18 on Soil and Rock and is the direct responsibility of Subcommittee D18.08 on Special and ConstructionControl Tests.Current edition approved S
13、ept. 1, 2008July 1, 2014. Published September 2008August 2014. Originally approved in 1991. Last previous edition approved in 20022008as D5195 02.D5195 08. DOI: 10.1520/D5195-08.10.1520/D5195-14.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at s
14、erviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.3 Replace with continuous flight and hollowstream methods when available.This document is not an ASTM standard and is intended only to provide the user of an ASTM sta
15、ndard 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 versionof the standard as published by AS
16、TM 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 States1D6938 Test Method for In-Place Density and Water Content of Soil and Soil-Ag
17、gregate by Nuclear Methods (Shallow Depth)3. Terminology3.1 DefinitionsSee For definitions of common technical terms in this standard, refer to Terminology D653 for generaldefinitions3.2 Definitions of Terms Specific to This Standard:3.2.1 wet densitysame as bulk density (as defined in Terminology D
18、653); the total mass (solids plus water) per total volume.3.2.2 gamma (radiation) sourcea sealed source of sealed, radioactive material that emits gamma radiation as it decays.3.2.3 gamma detectora device to detectobserve and measure gamma radiation.3.2.4 Compton scatteringthe interaction between a
19、gamma ray (photon) and an orbital electron where the gamma ray losesenergy and rebounds in a different direction.3.2.5 water contentthe ratio of the mass of water contained in the pore spaces of soil or soil-aggregate, to the solid mass ofparticles in that material, expressed as a percentage (this i
20、s sometimes referred to in some scientific fields as gravimetric watercontent to differentiate it from volumetric water content).3.2.5 volumetric water contentthe volume of water as a percent of the total volume of soil or rock material.4. Significance and Use4.1 This test method is useful as a rapi
21、d, nondestructive technique for the calculation of the in-place density of soil and rockat desired depths below the surface as opposed to surface measurements in accordance with Test Method D6938.4.2 This test method is useful for informational and research purposes. It should only be used for quali
22、ty control and acceptancetesting when correlated to other accepted methods such as Test Method D2937.4.3 The non-destructive nature of the test method allows repetitive measurements to be made at a single test location forstatistical analysis and to monitor changes over time.4.4 The fundamental assu
23、mptions inherent in this test method are that Compton scattering and photoelectric absorption are thedominant interactions of the gamma rays with the material under test.NOTE 1The quality of the result produced by this standard test method is dependent on the competence of the personnel performing i
24、t, and thesuitability of the equipment and facilities used. Agencies that meet the criteria of Practice D3740 are generally considered capable of competent andobjective testing/sampling/inspection, and the like. Users of this test method are cautioned that compliance with Practice D3740 does not in
25、itself assurereliable results. Reliable results depend on many factors; Practice D3740 provides a means of evaluating some of those factors.5. Interferences5.1 The chemical composition of the sample may affect the measurement and adjustments may be necessary. Some elementswith atomic numbers greater
26、 than 20 such as iron (Fe) or other heavy metals may cause measurements higher than the true densityvalue.5.2 The sample heterogeneity affects the measurements. This test method also exhibits spatial bias in that it is more sensitiveto material closest to the access tube.5.2.1 Voids around the acces
27、s tube can affect the measurement (see 9.1.2.1).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 greater the density the smaller the volume.6. Apparatus (See Fig. 1)FIG.
28、1 Schematic Diagram: Depth Density by Nuclear MethodD5195 1426.1 The apparatus shall consist of a nuclear instrument capable of measuring density of materials at various depths below thesurface and contain the following:6.1.1 Sealed Source of High Energy Gamma Radiation, such as cesium-137, cobalt-6
29、0, or radium-226.6.1.2 Gamma DetectorAny type of gamma detector such as a Geiger-Mueller tube.6.1.3 Suitable Timed Scaler and Power Source.6.2 Cylindrical ProbeThe apparatus shall be equipped with a cylindrical probe, containing the gamma source and detector,connected by a cable of sufficient design
30、 and length, that is capable of being lowered down a cased hole to desired test depths.6.3 Reference StandardThe apparatus shall be equipped with a reference standard, a fixed shape of dense material used forchecking apparatus operation and to establish conditions for a reproducible reference count
31、rate. It may also serve as a radiationshield.6.4 Apparatus PrecisionSee Annex A3 for the precision of the apparatus.6.5 Accessories:6.5.1 Access TubingThe access tubing (casing) is required for all access holes in nonlithified materials (soils and poorlyconsolidated rock) that cannot maintain consta
32、nt borehole diameter with repeated measurements. If access tubing is required itmust be of a material such as aluminum, steel, or polyvinyl chloride, having an interior diameter large enough to permit probeaccess without binding, and an exterior diameter as small as possible to provide close proximi
33、ty of the material under test. Thesame type of tubing must be used in the field as is used in calibration.6.5.2 Hand Auger or Power Drilling Equipment, that can be used to establish the access hole. Any drilling equipment thatprovides a suitable clean open hole for installation of access tubing and
34、insertion of the probe that ensures the measurements areperformed on undisturbedintact soil and rock while maintaining constant borehole diameter shall be acceptable. The type ofequipment and methods of advancing the access hole should be reported.7. Hazards7.1 These gauges utilize radioactive mater
35、ials that may be hazardous to the health of the users unless proper precautions aretaken. Users of these gauges must become familiar with applicable safety procedures and government regulations.7.2 Effective user instructions, together with routine safety procedures and knowledge of and compliance w
36、ith RegulatoryRequirements, are a mandatory part of the operation and storage of these gauges.8. Calibration, Standardization, and Reference Check8.1 Calibrate the instrument in accordance with Annex A1.8.2 Adjust the calibration in accordance with Annex A2 if adjustments are necessary.8.3 Standardi
37、zation and Reference Check:8.3.1 Nuclear density gauges are subject to long-term aging of the radioactive sources, which may change the relationshipbetween count rates and the material density. To correct for this aging effect, gauges are calibrated as a ratio of the measurementcount rate to a count
38、 rate made on a reference standard.8.3.2 Standardization of the gauge shall be performed at the start of each days use, and a record of these data should be retainedfor the amount of time required to ensure compliance with either Section 8.3.4 or 8.3.5, whichever is applicable. Perform thestandardiz
39、ation with the gauge far enough away from other apparatus containing radioactive sources to prevent interference dueto radiation from the other apparatus. In addition, perform the standardization far enough away from large masses or other itemswhich can affect the reference count rates due to reflec
40、tions from these masses or items.NOTE 2Separation of nuclear gauges by a distance of 9 m (30 ft) from one another has typically proven sufficient in preventing radiation from onegauge from being detected by another gauge and potentially causing an incorrect standardization count. This separation can
41、 be reduced by the proper useof shielding. With regards to reflections from large masses or other items potentially causing incorrect standardization counts, a separation of 1 m (3 ft)between the gauge and the mass or item in question has typically proven sufficient to prevent such reflections from
42、influencing the standardization counts.8.3.3 Turn on the gauge and allow for stabilization according to the manufacturers recommendations.8.3.4 Using the reference standard, take at least four repetitive readings at the normal measurement period and obtain the mean.If available on the gauge, one mea
43、surement at four or more times the normal measurement period is acceptable. This constitutesone standardization check. Use the procedure recommended by the gauge manufacturer to establish the compliance of the standardmeasurement to the accepted range. Without specific recommendations from the gauge
44、 manufacturer, use the procedure in 8.3.5.8.3.5 If the value of the current standardization count is outside the limits set by Eq 1, repeat the standardization check. If thesecond standardization check satisfies Eq 1, the gauge is considered in satisfactory operating condition.0.99Nc!e2ln2!tT1/2 #N0
45、#1.01Nc!e2ln2!tT1/2 (1)where:D5195 143T1/2 = the half-life of the isotope that is used for the density or moisture determination in the gauge. For example, 137Cs, theisotope most commonly used for density determination in these gauges, T1/2 is 11 023 days,Nc = the standardization count acquired at t
46、he time of the last calibration or verification,N0 = the current standardization count,t = the time that has elapsed between the current standardization test and the date of the last calibration or verification. Theunits selected for t and T1/2 should be consistent, that is, if T1/2 is expressed in
47、days, then t should also be expressed indays,ln( ) = the natural logarithm function, ande = the inverse of the natural logarithm function, equal to 2.71828182845904.e = the positive real number for which the natural logarithm value is equal to one. e itself is equal to 2.71828182845904.8.3.6 Example
48、A nuclear gauge containing a 137Cs source for density determination (half-life = 11 023 days) is calibrated onMarch 1 of a specific year.At the time of calibration, the density standard count was 2800 counts per minute (prescaled).Accordingto Eq 1, what is the allowed range of standard counts for No
49、vember 1 of the same year? For this example, a total of 245 days haveelapsed between the date of calibration or verification (March 1) and the date of the gauge standardization (November 1).Therefore:t = 245 daysT1/2 = 11 023 daysNc = 2800 countsAccording to Eq 1, therefore, the lower limit for the density standard count taken on November 1, denoted by N0, is0.99Nc!e2ln2!tT1/2 50.992800!e2ln2!24511 023 52772e20.0154152730 countsLikewise, the upper limit for the density standard count taken on November 1, denoted by N0, is1.01Nc!e2ln2!tT1/2 5
