1、Designation: D6031/D6031M 96 (Reapproved 2015)Standard Test Method forLogging In Situ Moisture Content and Density of Soil andRock by the Nuclear Method in Horizontal, Slanted, andVertical Access Tubes1This standard is issued under the fixed designation D6031/D6031M; the number immediately following
2、 the designation indicates theyear of original adoption or, in the case of 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.1. Scope1.1 This test method cove
3、rs collection and comparison oflogs of thermalized-neutron counts and back-scattered gammacounts along horizontal or vertical air-filled access tubes.1.2 The in situ water content in mass per unit volume andthe density in mass per unit volume of soil and rock at positionsor in intervals along the le
4、ngth of an access tube are calculatedby comparing the thermal neutron count rate and gamma countrates respectively to previously established calibration data.1.3 The values stated in either inch-pound units or SI unitspresented in brackets are to be regarded separately asstandard. The values stated
5、in each system may not be exactequivalents; therefore, each system shall be used independentlyof the other. Combining values from the two systems mayresult in non-conformance with the standard.1.3.1 The gravitational system of inch-pound units is usedwhen dealing with inch-pound units. In this syste
6、m, the pound(lbf) represents a unit of force (weight), while the unit for massis slugs. The rationalized slug unit is not given, unless dynamic(F = ma) calculations are involved.1.4 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is therespons
7、ibility 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. For specifichazards, see Section 6.2. Referenced Documents2.1 ASTM Standards:2D1452 Practice for Soil Exploration and Sampling by AugerB
8、oringsD1586 Test Method for Penetration Test (SPT) and Split-Barrel Sampling of SoilsD1587 Practice for Thin-Walled Tube Sampling of Soils forGeotechnical PurposesD2113 Practice for Rock Core Drilling and Sampling ofRock for Site ExplorationD2216 Test Methods for Laboratory Determination of Water(Mo
9、isture) Content of Soil and Rock by MassD2922 Test Methods for Density of Soil and Soil-Aggregatein Place by Nuclear Methods (Shallow Depth) (With-drawn 2007)3D2937 Test Method for Density of Soil in Place by theDrive-Cylinder MethodD3017 Test Method for Water Content of Soil and Rock inPlace by Nuc
10、lear Methods (Shallow Depth)D3550 Practice for Thick Wall, Ring-Lined, Split Barrel,Drive Sampling of SoilsD4428/D4428M Test Methods for Crosshole Seismic Test-ingD4564 Test Method for Density and Unit Weight of Soil inPlace by the Sleeve Method (Withdrawn 2013)3D5195 Test Method for Density of Soil
11、 and Rock In-Place atDepths Below Surface by Nuclear MethodsD5220 Test Method for Water Mass per Unit Volume of Soiland Rock In-Place by the Neutron Depth Probe Method3. Significance and Use3.1 This test method is useful as a repeatable, nondestruc-tive technique to monitor in-place density and mois
12、ture of soiland rock along lengthy sections of horizontal, slanted, andvertical access holes or tubes. With proper calibration inaccordance with Annex A1, this test method can be used toquantify changes in density and moisture content of soil androck.3.2 This test method is used in vadose zone monit
13、oring, forperformance assessment of engineered barriers at wastefacilities, and for research related to monitoring the movementof liquids (water solutions and hydrocarbons) through soil and1This test method is under the jurisdiction ofASTM Committee D18 on Soil andRock and is the direct responsibili
14、ty of Subcommittee D18.21 on Groundwater andVadose Zone Investigations.Current edition approved Nov. 1, 2015. Published November 2015. Originallyapproved in 1996. Last previous edition approved in 2010 as D603196(2010)1.DOI: 10.1520/D6031_D6031M-96R15.2For referenced ASTM standards, visit the ASTM w
15、ebsite, 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.3The last approved version of this historical standard is referenced onwww.astm.org.Copyright ASTM Internatio
16、nal, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1rock. The nondestructive nature of the test allows repetitivemeasurements at a site and statistical analysis of results.3.3 The fundamental assumptions inherent in this testmethod are that the dry bulk density o
17、f the test material isconstant and that the response to fast neutrons and gammarayenergy associated with soil and liquid chemistry is constant.4. Interferences4.1 The sample heterogeneity and chemical composition ofthe material under test will affect the measurement of bothmoisture and density. The
18、apparatus should be calibrated to thematerial under test at a similar density of dry soil or rock andin the similar type and orientation of access tube, or adjust-ments must be made in accordance with Annex A2.4.2 Hydrogen, in forms other than water, as defined by TestMethod D2216, will cause measur
19、ements in excess of the truemoisture content. Some elements such as boron, chlorine, andminute quantities of cadmium, if present in the material undertest, will cause measurements lower than the true moisturecontent. Some elements with atomic numbers greater than 20such as iron or other heavy metals
20、 may cause measurementshigher than the true density value.4.3 The measurement of moisture and density using this testmethod exhibits spatial bias in that it is more sensitive to thematerial closest to the access tube. The density and moisturemeasurements are necessarily an average of the total sampl
21、einvolved.4.4 The sample volume for a moisture measurement isapproximately 3.8 ft30.11 m3 at a moisture content of 12.5lbf/ft3200 kg/m3. The actual sample volume for moisture isindeterminate and varies with the apparatus and the moisturecontent of the material. In general the greater the moisturecon
22、tent of the material, the smaller the measurement volume.4.5 Adensity measurement has a sample volume of approxi-mately 0.8 ft30.028 m3. The actual sample volume fordensity is indeterminate and varies with the apparatus and thedensity of the material. In general, the greater the density of themateri
23、al, the smaller the measurement volume.4.6 Air gaps between the probe and the access tube or voidsaround the access tube will cause the indicated moisturecontent and density to be less than the calibrated values.4.7 Condensed moisture inside the access tube may causethe indicated moisture content to
24、 be greater than the truemoisture content of material outside the access tube.5. Apparatus5.1 While exact details of construction of the apparatus mayvary, the system shall consist of:5.1.1 Fast Neutron SourceA sealed mixture of a radioac-tive material such as americium or radium and a target materi
25、alsuch as beryllium, or other fast neutron sources such ascalifornium that do not require a target.5.1.2 Slow Neutron DetectorAny type of slow neutrondetector, such as boron trifluoride or helium-3 proportionalcounters.5.1.3 High-Energy Gamma-Radiation SourceA sealedsource of radioactive material, s
26、uch as cesium-137, cobalt-60,or radium-226.5.1.4 Gamma DetectorAny type of gamma detector, suchas a Geiger-Mueller tube.5.1.5 Suitable Readout Device:5.1.6 Cylindrical ProbeThe apparatus shall be equippedwith a cylindrical probe, containing the neutron and gammasources and the detectors, connected b
27、y a cable or cables ofsufficient design and length, that are capable of raising andlowering the probe in vertical applications and pulling it inhorizontal applications, to the desired measurement location.5.1.7 Reference StandardA device containing dense, hy-drogenous material for checking equipment
28、 operation and toestablish conditions for a reproducible reference count rate. Italso may serve as a radiation shield.5.2 Accessories shall include:5.2.1 Access TubingThe access tubing (casing) is requiredfor all access holes in nonlithified materials (soils and poorlyconsolidated rock) that cannot
29、maintain constant boreholediameter with repeated measurements. If access tubing isrequired it must be of a material, such as aluminum, steel, orplastic, having an interior diameter large enough to permitprobe access without binding, and an exterior diameter as smallas possible to provide close proxi
30、mity of the material undertest. The same type of tubing must be used in the field as isused in calibration.5.2.2 Hand Auger or Power Drilling/TrenchingEquipmentEquipment that can be used to establish the accesshole or position the access tube when required (see 5.2.1). Anyequipment that provides a s
31、uitable clean open hole for instal-lation of access tubing and insertion of the probe that ensuresthe measurements are performed on undisturbed soil and rockwhile maintaining a constant diameter per width shall beacceptable. The type of equipment and methods of advancingthe access hole should be rep
32、orted.5.2.3 Winching Equipment or Other Motive DevicesEquipment that can be used to move the probe through theaccess tubing. The type of such equipment is dependent uponthe orientation of the access tubing and the distance over whichthe probe must be moved.6. Hazards6.1 WarningThis equipment utilize
33、s radioactive materi-als that may be hazardous to the health of the users unlessproper precautions are taken. Users of this equipment mustbecome completely familiar with all possible safety hazardsand with all applicable regulations concerning the handling anduse of radioactive materials. Effective
34、user instructions to-gether with routine safety procedures are a recommended partof the operation of this apparatus.6.2 WarningWhen using winching or other motiveequipment, the user should take additional care to learn itsproper use in conjunction with measurement apparatus. Knownsafety hazards such
35、 as cutting and pinching exist when usingsuch equipment.D6031/D6031M 96 (2015)26.3 This test method does not cover all safety precautions. Itis the responsibility of the users to familiarize themselves withall safety precautions.7. Calibration, Standardization, and Reference Check7.1 Calibrate the i
36、nstrument in accordance with Annex A1.7.2 Adjust the calibration in accordance with Annex A2 ifadjustments are necessary.7.3 Standardization and Reference Check:7.3.1 Nuclear apparatus are subject to the long-term decayof the radioactive source and aging of detectors and electronicsystems that may c
37、hange the relationship between count rateand either the material density or the moisture content of thematerial, or both. To correct for these changes, the apparatusmay be calibrated periodically. To minimize error, moistureand density measurements commonly are reported as countratios, the ratio of
38、the measured count rate to a count rate madein a reference standard. The reference count rate should besimilar or higher than the count rates over the useful measure-ment range of the apparatus.7.3.2 Standardization of equipment on the reference stan-dard is required at the start of each days use an
39、d a permanentrecord of these data shall be retained. The standardization shallbe performed with the equipment located at least 33 ft 10 maway from other radioactive sources and large masses or otheritems that may affect the reference count rate.7.3.3 If recommended by the apparatus manufacturer topr
40、ovide more stable and consistent results, turn on the appara-tus prior to use to allow it to stabilize and leave the power onduring the days testing.7.3.4 Using the reference standard, take at least four repeti-tive readings at the manufacturers recommended measurementperiod of 20 or more at some sh
41、orter period and obtain themean. If available on the instrument, one measurement at aperiod of four or more times the normal test measurementperiod is acceptable. This constitutes one standardizationcheck.7.3.5 If the value obtained in 7.3.4 is within the followinglimits, the equipment is considered
42、 to be in satisfactorycondition and the value may be used to determine the countratios for the day of use. If the value obtained is outside theselimits, another standardization check should be made. If thesecond standardization check is within the limits, the equip-ment may be used. If it also fails
43、 the test, however, theequipment shall be adjusted or repaired as recommended by themanufacturer.No12FNoF.Ns.No 2 2FNoFwhere:Ns = value of current standardization check (7.3.4)onthereference standard,No = average of the past values of Ns taken for prior usage,andF = value of prescale, a multiplier t
44、hat alters the countvalue for the purpose of display (see A3.1.1.1).7.3.6 If the apparatus standardization has not been checkedwithin the previous three months, perform at lest four newstandardization checks and use the mean as the value for No.7.3.7 The value of Ns will be used to determine the cou
45、ntratios for the current days use of the equipment. If, for anyreason, either the measured density or moisture content be-come suspect during the days use, perform another standard-ization to ensure that the equipment is stable.8. Procedure8.1 Installation of Access Tubing (Casing):8.1.1 Drill the a
46、ccess hole or excavate a trench at the desiredlocation and install the access tube in a manner to maximizecontact with test material and minimize voids. The access tubesshould fit snugly into the access hole or trench. Unstableconditions in fill material around the access tube may result inredistrib
47、ution of solids over time, piping, or other phenomenathat will degrade precision. Voids caused during drilling, tubeinstallation, or backfilling, or a combination thereof, may causeerroneously low results. Excessive compaction of clay-richbackfill material will limit the effectiveness of moisture mo
48、ni-toring for leak detection. Backfill should approximate thecomposition, water content, and bulk density of test material asnearly as possible.8.1.2 Grouting of annular spaces, if required, should be ofminimum functional thickness, and grout mixtures should notcontain excessive water. Grouts thicke
49、r than 2 in. 5 cm createhigh background counts that will obscure moisture contentchanges in fine-textured soils and severely limit meaningfuldensity measurements in all soil types. Grouting should not beused unless it is required to seal off flow pathways along theaccess tube, such as in some vertical borings and wheretrenches cross engineered barriers. Grouting can be accom-plished using procedures described in Test Methods D4428/D4428M.8.1.3 Record and note the position of the groundwater table,perched water tables, and changes in soil texture as dril
