1、Designation: D 6031 96 (Reapproved 2004)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 D 6031; the number immediately following the designa
2、tion indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers collecti
3、on 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 length of an
4、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 SI units are regarded as thestandard. The inch-pound units given in parentheses may beapproximate and are provided for informati
5、on only.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 health practices and determine the applica-bility of regulatory limitations prior to use. For sp
6、ecifichazards, see Section 6.2. Referenced Documents2.1 ASTM Standards:2D 1452 Practice for Soil Investigation and Sampling byAuger BoringsD 1586 Test Method for Penetration Test and Split/BarrelSampling of SoilsD 1587 Practice for Thin-Walled Tube Sampling of SoilsD2113 Practice for Diamond Core Dr
7、illing for Site Inves-tigationD 2216 Test Method for Laboratory Determination of Water(Moisture) Content of Soil and RockD 2922 Test Methods for Density of Soil and Soil-Aggregate in Place by Nuclear Methods (Shallow Depth)D 2937 Test Method for Density of Soil in Place by theDrive-Cylinder MethodD
8、3017 Test Method for Water Content of Soil and Rock inPlace by Nuclear Methods (Shallow Depth)D 4428/D 4428M Test Methods of Crosshole Seismic Test-ingD 4564 Test Method for Density of Soil in Place by theSleeve MethodD 5195 Test Method for Density of Soil and Rock In-Placeat Depths Below the Surfac
9、e by Nuclear MethodsD 5220 Test Method for Water Content of Soil and RockIn-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 moisture of soiland rock along lengthy sections of horiz
10、ontal, 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 monitoring, forperformance assessment of engineered barri
11、ers at waste facili-ties, and for research related to monitoring the movement ofliquids (water solutions and hydrocarbons) through soil androck. The nondestructive nature of the test allows repetitivemeasurements at a site and statistical analysis of results.3.3 The fundamental assumptions inherent
12、in this testmethod are that the dry bulk density of 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
13、 the measurement of bothmoisture and density. The 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,
14、 as defined by TestMethod D 2216, will cause measurements in excess of the truemoisture content. Some elements such as boron, chlorine, and1This test method is under the jurisdiction ofASTM Committee D18 on Soil andRock and is the direct responsibility of Subcommittee D18.21 on Ground Water andVados
15、e Zone Investigations.Current edition approved Nov. 1, 2004. Published December 2004. Originallyapproved in 1996. Last previous edition approved in 1996 as D 603196.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Bo
16、ok of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.minute quantities of cadmium, if present in the material undertest, will cause me
17、asurements lower than the true moisturecontent. Some elements with atomic numbers greater than 20such as iron or other heavy metals 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 sens
18、itive to thematerial closest to the access tube. The density and moisturemeasurements are necessarily an average of the total sampleinvolved.4.4 The sample volume for a moisture measurement isapproximately 0.11 m3(3.8 ft3) at a moisture content of 200kg/m3(12.5 lbf/ft3). The actual sample volume for
19、 moisture isindeterminate and varies with the apparatus and the moisturecontent of the material. In general the greater the moisturecontent of the material, the smaller the measurement volume.4.5 Adensity measurement has a sample volume of approxi-mately 0.028 m3(0.8 ft3). The actual sample volume f
20、ordensity is indeterminate and varies with the apparatus and thedensity of the material. In general, the greater the density of thematerial, 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 a
21、nd density to be less than the calibrated values.4.7 Condensed moisture inside the access tube may causethe indicated moisture content to 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 sys
22、tem shall consist of:5.1.1 Fast Neutron SourceA sealed mixture of a radioac-tive material such as americium or radium and a target materialsuch 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, suc
23、h as boron trifluoride or helium-3 proportionalcounters.5.1.3 High-Energy Gamma-Radiation Source A sealedsource of radioactive material, such 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 Cylind
24、rical ProbeThe apparatus shall be equippedwith a cylindrical probe, containing the neutron and gammasources and the detectors, connected by a cable or cables ofsufficient design and length, that are capable of raising andlowering the probe in vertical applications and pulling it inhorizontal applica
25、tions, to the desired measurement location.5.1.7 Reference StandardA device containing dense, hy-drogenous material for checking equipment 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 T
26、ubingThe 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, orplastic, having an
27、 interior diameter large enough to permitprobe access without binding, and an exterior diameter as smallas possible to provide close proximity 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/TrenchingEquipmentEq
28、uipment that can be used to establish the accesshole or position the access tube when required (see 5.2.1). Anyequipment that provides a suitable clean open hole for instal-lation of access tubing and insertion of the probe that ensuresthe measurements are performed on undisturbed soil and rockwhile
29、 maintaining a constant diameter per width shall beacceptable. The type of equipment and methods of advancingthe access hole should be reported.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 depende
30、nt uponthe orientation of the access tubing and the distance over whichthe probe must be moved.6. HazardsNOTE 1Warning: This equipment utilizes radioactive materials thatmay be hazardous to the health of the users unless proper precautions aretaken. Users of this equipment must become completely fam
31、iliar with allpossible safety hazards and with all applicable regulations concerning thehandling and use of radioactive materials. Effective user instructionstogether with routine safety procedures are a recommended part of theoperation of this apparatus.NOTE 2Caution: When using winching or other m
32、otive equipment,the user should take additional care to learn its proper use in conjunctionwith measurement apparatus. Known safety hazards such as cutting andpinching exist when using such equipment.NOTE 3This test method does not cover all safety precautions. It is theresponsibility of the users t
33、o familiarize themselves with all safetyprecautions.7. Calibration, Standardization, and Reference Check7.1 Calibrate the instrument 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 ap
34、paratus are subject to the long-term decayof the radioactive source and aging of detectors and electronicsystems that may change 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 calib
35、rated periodically. To minimize error, moistureand density measurements commonly are reported as countratios, the ratio of 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
36、of the apparatus.7.3.2 Standardization of equipment on the reference stan-dard is required at the start of each days use and a permanentrecord of these data shall be retained. The standardization shallbe performed with the equipment located at least 10 m (33 ft)away from other radioactive sources an
37、d large masses or otheritems that may affect the reference count rate.D 6031 96 (2004)27.3.3 If recommended by the apparatus manufacturer toprovide 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 Usi
38、ng the reference standard, take at least four repeti-tive readings at the manufacturers recommended measurementperiod of 20 or more at some shorter period and obtain themean. If available on the instrument, one measurement at aperiod of four or more times the normal test measurementperiod is accepta
39、ble. This constitutes one standardizationcheck.7.3.5 If the value obtained in 7.3.4 is within the followinglimits, the equipment is considered 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, anoth
40、er standardization check should be made. If thesecond standardization check is within the limits, the equip-ment may be used. If it also fails the test, however, theequipment shall be adjusted or repaired as recommended by themanufacturer.No 1 2FNoF. Ns . No 2 2FNoFwhere:Ns = value of current standa
41、rdization check (7.3.4)onthereference standard,No = average of the past values of Ns taken for priorusage, andF = value of prescale, a multiplier that 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
42、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 countratios for the current days use of the equipment. If, for anyreason, either the measured density or moisture content be-come suspect during the days us
43、e, perform another standard-ization to ensure that the equipment is stable.8. Procedure8.1 Installation of Access Tubing (Casing):8.1.1 Drill the access hole or excavate a trench at the desiredlocation and install the access tube in a manner to maximizecontact with test material and minimize voids.
44、The access tubesshould fit snugly into the access hole or trench. Unstableconditions in fill material around the access tube may result inredistribution of solids over time, piping, or other phenomenathat will degrade precision. Voids caused during drilling, tubeinstallation, or backfilling, or a co
45、mbination thereof, may causeerroneously low results. Excessive compaction of clay-richbackfill material will limit the effectiveness of moisture moni-toring for leak detection. Backfill should approximate thecomposition, water content, and bulk density of test material asnearly as possible.8.1.2 Gro
46、uting of annular spaces, if required, should be ofminimum functional thickness, and grout mixtures should notcontain excessive water. Grouts thicker than 5 cm (2 in.) createhigh background counts that will obscure moisture contentchanges in fine-textured soils and severely limit meaningfuldensity me
47、asurements 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 D 4428/D 4428M.8.1.3 R
48、ecord and note the position of the ground watertable, perched water tables, and changes in soil texture asdrilling or trenching progresses.8.1.4 If ground water is encountered or saturated conditionsare expected to develop, seal the tube at seams and open endsto prevent water seepage into the tube.
49、This will preventerroneous measurements and possible damage to the probe.8.1.5 The access tube should project above the ground andbe capped to prevent foreign material from entering. Theaccess tube should not project out of the test material farenough to be damaged by equipment traffic.8.2 Pass a dummy probe through the access tube to verifyproper clearance before deploying the radioactive sources.8.3 Standardize the apparatus (see 7.3).8.4 Proceed with the test run in a continuous logging modeor in a noncontinuous logging mode as follows:8.4.1 Set up the winching e
