1、Designation: D5334 08D5334 14Standard Test Method forDetermination of Thermal Conductivity of Soil and SoftRock by Thermal Needle Probe Procedure1This standard is issued under the fixed designation D5334; 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. Scope*1.1 This test method presents a procedure for determining the thermal conductivity () o
3、f soil and soft rock using a transientheat method. This test method is applicable for both undisturbedintact and remoldedreconstituted soil specimens and soft rockspecimens. This test method is suitable only for isotropichomogeneous materials.1.2 This test method is applicable to dry or unsaturated
4、materials over a wide temperature range temperatures ranging from 100C, depending on the suitability of the thermal needle probe construction to temperature extremes. This method may alsobe used for specimens containing moisture. However, care must be taken to prevent significant error from: (1) red
5、istribution ofwater due to thermal gradients resulting from heating of the needle probe, and probe; (2) redistribution of water due to hydraulicgradients (gravity drainage for high degrees of saturation or surface evaporation); (3) phase change (melting) of icewater inspecimens with temperatures 100
6、C. These errors can be minimized by adding less total heat to thespecimen either through either minimizing power applied to the needle probe and/or minimizing the heating duration of themeasurement.1.3 For satisfactory results in conformance with this test method, the principles governing the size,
7、construction, and use of theapparatus described in this test method should be followed. If the results are to be reported as having been obtained by this testmethod, then all pertinent requirements prescribed in this test method shall be met.1.4 It is not practicable in a test method of this type to
8、 aim to establish details of construction and procedure to cover allcontingencies that might offer difficulties to a person without technical knowledge concerning the theory of heat flow, temperaturemeasurement, and general testing practices. Standardization of this test method does not reduce the n
9、eed for such technicalknowledge. It is recognized also that it would be unwise, because of the standardization of this test method, to resist in any waythe further development of improved or new methods or procedures by research workers.1.3 UnitsThe values stated in SI units are to be regarded as th
10、e standard. The inch-pound units given in parentheses are forinformation only.No other units of measurements are included in this standard.1.4 All measuredobserved and calculated values shall conform to the guidelines for significant digits and rounding establishedInin Practice D6026.1.4.1 The proce
11、dure used to specify how data are collected/recorded or calculated in this standard are regarded as the industrystandard. In addition, they are representative of the significant digits that generally should be retained. The procedures used do notconsider material variation, purpose for obtaining the
12、 data, special purpose studies, or any considerations for the users objectives;and it is common practice to increase or reduce significant digits of reported data to be commensurate with these considerations.It is beyond the scope of this standard to consider significant digits used in analytical me
13、thods for engineering design.1.5 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 applicability of regulatorylimitations p
14、rior to use.2. Referenced Documents2.1 ASTM Standards:2D653 Terminology Relating to Soil, Rock, and Contained Fluids1 This test method is under the jurisdiction of ASTM Committee D18 on Soil and Rock and is the direct responsibility of Subcommittee D18.12 on Rock Mechanics.Current edition approved J
15、uly 1, 2008June 1, 2014. Published July 2008July 2014. Originally approved in 1992. Last previous edition approved in 20052008 asD5334 05.D5334 08. DOI: 10.1520/D5334-08.10.1520/D5334-0814.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at service
16、astm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Bec
17、auseit 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 ASTM is to be considered the official document.*A Summary of Changes section appe
18、ars at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1D2216 Test Methods for Laboratory Determination of Water (Moisture) Content of Soil and Rock by MassD3740 Practice for Minimum Requirements for Agencies En
19、gaged in Testing and/or Inspection of Soil and Rock as Used inEngineering Design and ConstructionD4439 Terminology for GeosyntheticsD4753 Guide for Evaluating, Selecting, and Specifying Balances and Standard Masses for Use in Soil, Rock, and ConstructionMaterials TestingD6026 Practice for Using Sign
20、ificant Digits in Geotechnical Data3. Terminology3.1 DefinitionsFor terminology used in this test method, refer to Terminologies definitions of common technical terms, referto Terminology standards D653 and D4439.3.2 Definitions of Terms Specific to This Standard:3.2.1 heat inputinput, npower consum
21、ption of heater wire in watts per unit length that is assumed to be the equivalent ofheat output per unit length of wire.3.2.2 thermal epoxyepoxy, nany thermallyheat conductive filled epoxy resin material having a value of 4W/(mk).W/(mK).3.2.3 thermal greasegrease, nany thermally conductivity grease
22、 heat conductive lubricating material having a value of 4 W/(mk).W/(mK).4. Summary of Test Method4.1 The thermal Thermal conductivity is determined by a variation of the line source test method using a needle probe havinga large length to diameter ratio to simulate conditions for an infinitely long,
23、 infinitely thin heating source. The probe consists ofa heating element and a temperature measuring element and is inserted into the specimen.Aknown current and voltage are appliedto the probe and the temperature rise with time is recorded over a period of time. The temperature decay with time after
24、 thecessation of heating can also be included in the analysis to minimize effects of temperature drift during measurement. The thermalThermal conductivity is obtained from an analysis of the temperature time series temperature data during the heating cycle andcooling cycle if applicable.5. Significa
25、nce and Use5.1 The thermal conductivity of both undisturbedintact and remoldedreconstituted soil specimens as well as soft rock specimensis used to analyze and design systems used, for example, in underground transmission lines, oil and gas pipelines, radioactive wastedisposal, geothermal applicatio
26、ns, and solar thermal storage facilities.NOTE 1Notwithstanding the statements on precision and bias contained in this test method; the precision of this test method The quality of the resultproduced by this standard is dependent on the competence of the personnel performing it, and the suitability o
27、f the equipment and facilities used.Agenciesthat meet the criteria of Practice D3740 are generally considered capable of competent and objective testing. Users of this test method standard arecautioned that compliance with Practice D3740 does not in itself assureensure reliable testing.results. Reli
28、able testing dependsresults depend on manyfactors; Practice D3740 provides a means of evaluating some of those factors.6. Apparatus6.1 Thermal Needle ProbeA device that creates a linear heat source and incorporates a temperature measuring element(thermocouple or thermistor)thermocouple or thermistor
29、 to measure the variation of temperature at a point along the line. Theconstruction of a suitable device is described in Annex A1.6.2 Constant Current SourceA device to produce a constant current.6.3 Temperature Readout Unit or RecorderA device to record or produce a digital readout of temperature i
30、n degrees Celsiuswith enough resolution to resolve changes in temperature induced by heating of the needle (typically 0.1 to 0.01 K).the temperaturefrom the thermocouple or thermistor with a readability of 0.01 K or better.6.4 Voltage-Ohm-Meter (VOM)A device to read voltage and current to the neares
31、t 0.01 V and ampere. 0.01 A.6.5 Timer, TimerstopwatchAclock, stopwatch, digital timer, or integrated electronic timer capable of measuring to the nearest0.1 s or better for the duration of the measurement.6.6 Equipment, Drilling DeviceAdrill capable of drillingmaking a straight vertical hole having
32、a diameter as close as possibleto that of the needle and to a depth at least equal equivalent to the length of the needle.6.7 BalanceA balance that meets the requirements of Guide D4753 and has a readability of 0.01 g for specimens having amass of up to 200 g and a readability of 0.1 g for specimens
33、 with a mass over 200 g. However, the balance used may be controlledby the number of significant digits needed.7. Specimen Preparation7.1 UndisturbedIntact Soil Specimens : Specimens:D5334 1427.1.1 Thin-Walled Tube or Drive Specimens SpecimensCut a 200 6 30-mm (8.0 6 1-in.) long section of a samplin
34、g tubecontaining an undisturbedintact soil specimen. The tube section shouldshall have a minimum diameter of 51 mm (2 in.).50 mm.7.1.2 Weigh the Determine and record the mass of the specimen in a sampling tube or brass rings.ring to the nearest 0.01 gram.7.1.3 Measure and record the length and diame
35、ter of the specimen to 0.1 mm. Take a minimum of three length measurements120 apart and at least three diameter measurements at the quarter points of the height. Determine the average length and diameterof the specimen.7.1.4 Insert the thermal needle probe down the axis of the specimen by either pus
36、hing the probe into a predrilled hole (densespecimen) to a depth equal to the length of the probe or pushing the probe into the specimen (loose specimen). Care should betaken to ensure that Make sure the thermal probe shaft is fully embedded in the specimen and not left partially exposed. (SeeSeeNot
37、e 2.).NOTE 2To provide better thermal contact between the specimen and the probe, the probe may be coated with a thin layer of thermal grease. If a holeis predrilled for the needle probe, the diameter of the hole should be equalequivalent to the diameter of the needle probe to ensure make sure there
38、 isa tight fit. A device, such as a drill press, may be used to insert the probe to ensure thatmake sure the probe is inserted vertically and that no void spacesare formed between the specimen and the probe.7.2 RemoldedReconstituted Soil Specimens:7.2.1 Compact the specimen to the desired dry densit
39、y and gravimetric water content (inin a thin-walled metal or plastictube)tube using an appropriate compaction technique. For further guidance on the effect of the various compaction techniques onthermal conductivity, refer to Mitchell et alal. (1).3 The tube shouldshall have a minimum diameter of 51
40、50 mm (2 in.) and a lengthof 200 6 30 mm (8.0 6 1 in.).mm.7.2.2 Perform Follow the procedure given 7.1.2, 7.1.3, and 7.1.37.1.4.7.3 Soft Rock Specimens:7.3.1 Specimen Determine and record the mass of the specimen to the nearest 0.01 g and follow the procedure given in 7.1.4to determine the specimen
41、diameter and length. The specimen dimensions shall be no less than those of the calibration standard(8.3).7.3.2 Insert the thermal needle probe into the specimen by predrilling a hole to a depth equalequivalent to the length of theprobe. Care should be taken to ensure that Make sure the thermal prob
42、e shaft is fully embedded in the specimen and not leftpartially exposed. (SeeSee Note 2.).8. Calibration8.1 The thermal needle probe apparatus shouldshall be calibrated before its use. Perform calibration by comparing theexperimental determination of the thermal conductivity of a standard material t
43、o its known value. A calibration factor, C, shouldbe calculated where:is calculated as follows:C 5 materialmeasured(1)where:material = the known thermal conductivity of the calibration material, andmeasured = the thermal conductivity of that material measured with the thermal needle probe apparatus.
44、8.1.1 All subsequent measurements with the thermal needle probe apparatus shouldshall be multiplied by C before beingreported. This isAlthough calibration is mandatory, it is especially important with large diameter needle probes (that is, d 2.52.54mm) where departures from the assumption of an infi
45、nitely thin probe cause potentially significant differences in estimation of thethermal conductivity due to non-negligible heat storage and transmission in the needle probe itself.8.1.2 The calibration factor, C, has been shown to be a function of thermal conductivity when using a large diameter nee
46、dleprobe (see Hanson et al,al., 2004) (2). For users of large diameter probes, it may be necessary to determine C at several thermalconductivities in the range of measurement and construct a calibration function which is then applied to subsequent data collectedwith the thermal needle probe.3 The bo
47、ldface numbers given in parentheses refer to the list of references at the end of this standard.FIG. 1 Thermal Probe Experimental SetupD5334 1438.2 Conduct the test specified in Section 9 using a calibration standard as specified in 8.3.8.3 Calibration StandardOne or more materials with known values
48、 of thermal conductivity in the range of the materials beingmeasured (typically measured, which is typically 0.2 Q4pilnt! 0,t#t1 (4)T Q4pilnS tt 2t1D t.t1 (5)10.2 Simplified Method:10.2.1 For thermal needle probes with diameter of 2.52.54 mm or less, exclude from the analysis the first 10 to 30 seco
49、nds ofdata from both the heating and, if used, cooling data. For larger diameter thermal needle probes it will be necessary to plot thedata on a semi-log plot as described in 10.2.2 and identify the duration of the non-linear portion of initial data that shouldshall beexcluded. These data are most strongly affected by terms ignored in Eq 4 and 5, and will result in decreased accuracy if they areincluded in the subsequent analysis. The total time duration of the data included in the analysis, and duration of initial valuesexcluded from t
