ASTM D4612-2016 Standard Test Method for Calculating Thermal Diffusivity of Rock and Soil《测定岩土热扩散系数的标准试验方法》.pdf
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1、Designation: D4612 16Standard Test Method forCalculating Thermal Diffusivity of Rock and Soil1This standard is issued under the fixed designation D4612; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A n
2、umber 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 involves calculation of the thermaldiffusivity from measured values of the mass density, thermalconductivity, and spec
3、ific heat at constant pressure. It isapplicable for any materials where these data can be deter-mined. The temperature range covered by this test method is293 to 573 K. This test method is closely linked to the overalltest procedure used in obtaining the primary data on density,specific heat, and th
4、ermal conductivity. It cannot be used as a“stand alone” test method because the thermal diffusivityvalues calculated by this test method are dependent on thenature of the primary data base. The test method furnishesgeneral guidelines to calculate the thermal diffusivity butcannot be considered to be
5、 all-inclusive to capture issuesrelated to the density, specific heat, and thermal conductivityNOTE 1The diffusivity, as determined by this test method, is intendedto be a volume average value, with the averaging volume being 2105m3(20 cm3). This requirement necessitates the use of specimens withvol
6、umes greater than the minimum averaging volume and precludes use offlash methods of measuring thermal diffusivity, such as the laser pulsetechnique.1.2 The values stated in SI units are to be regarded as thestandard. No other units of measurements are included in thisstandard.1.3 This test method is
7、 intended to apply to isotropicsamples; that is, samples in which the thermal transportproperties do not depend on the direction of heat flow. If thethermal conductivity depends on the direction of heat flow,then the diffusivity derived by this test method must beassociated with the same direction a
8、s that utilized in theconductivity measurement.1.4 The thermal conductivity, specific heat, and mass den-sity measurements must be made with specimens that are asnear identical in composition and water content as possible.1.5 The generally inhomogeneous nature of geologic forma-tions precludes the u
9、nique specification of a thermal diffusivitycharacterizing an entire rock formation or soil layer. Geologicmedia are highly variable in character, and it is impossible tospecify a test method for diffusivity determination that will besuitable for all possible cases. Some of the most importantlimitat
10、ions arise from the following factors:1.5.1 Variable MineralogyIf the mineralogy of the forma-tion under study is highly variable over distances on the sameorder as the size of the sample from which the conductivity,specific heat, and density specimens are cut, then the calculateddiffusivity for a g
11、iven set of specimens will be dependent onthe precise locations from which these specimens were ob-tained.1.5.2 Variable PorosityThe thermal properties of porousrock or soil are highly dependent on the amount and nature ofthe porosity. A spatially varying porosity introduces problemsof a nature simi
12、lar to those encountered with a spatially varyingcomposition. In addition, the character of the porosity maypreclude complete dehydration by oven drying.1.6 All observed and calculated values shall conform to theguidelines for significant digits and rounding established inPractice D6026.1.6.1 The pr
13、ocedure used to specify how data are collected/recorded or calculated in this standard are regarded as theindustry standard. In addition, they are representative of thesignificant digits that generally should be retained. The proce-dures used do not consider material variation, purpose forobtaining
14、the 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 analytical
15、methods for engineering design.1.7 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 limitatio
16、ns prior to use.1This test metis under the jurisdiction of ASTM Committee D18 on Soil andRock and is the direct responsibility of Subcommittee D18.12 on Rock Mechanics.Current edition approved May 1, 2016. Published May 2016. Originallyapproved in 1986. Last previous edition approved in 2008 as D461
17、2 08. DOI:10.1520/D4612-16.*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 States12. Referenced Documents2.1 ASTM Standards:2C177 Test Method for Steady-State Heat Flux Measure
18、-ments and Thermal Transmission Properties by Means ofthe Guarded-Hot-Plate ApparatusC518 Test Method for Steady-State Thermal TransmissionProperties by Means of the Heat Flow Meter ApparatusC642 Test Method for Density, Absorption, and Voids inHardened ConcreteD653 Terminology Relating to Soil, Roc
19、k, and ContainedFluidsD2216 Test Methods for Laboratory Determination of Water(Moisture) Content of Soil and Rock by MassD3740 Practice for Minimum Requirements for AgenciesEngaged in Testing and/or Inspection of Soil and Rock asUsed in Engineering Design and ConstructionD4611 Test Method for Specif
20、ic Heat of Rock and SoilD4753 Guide for Evaluating, Selecting, and Specifying Bal-ances and Standard Masses for Use in Soil, Rock, andConstruction Materials TestingD5334 Test Method for Determination of Thermal Conduc-tivity of Soil and Soft Rock by Thermal Needle ProbeProcedureD6026 Practice for Us
21、ing Significant Digits in GeotechnicalDataE145 Specification for Gravity-Convection and Forced-Ventilation Ovens3. Terminology3.1 Definitions:3.1.1 For definitions of common technical terms used in thisstandard, refer to Terminology D653.3.2 Symbols:3.2.1 mass density (kg/m3).3.2.2 instantaneous spe
22、cific heatcp(J/kgK).3.2.3 thermal conductivityk (W/mK).3.2.4 thermal diffusivity (m2/s).3.2.5 enthalpyh.4. Summary of Test Method4.1 The thermal diffusivity is determined from the equationin 9.3. The data for k and cpmust be available over thetemperature range of interest. For density, , a single me
23、asure-ment at room temperature may be used because the density isapproximately constant over the 293 to 573 K temperaturerange covered by this test method.4.2 The measurements of k, , and cpare to be performedusing the test methods in Section 8.5. Significance and Use5.1 The thermal diffusivity is a
24、 parameter that arises in thesolution of transient heat conduction problems. It generallycharacterizes the rate at which a heat pulse will diffuse througha solid material.5.2 The number of parameters required for solution of atransient heat conduction problem depends on both the geom-etry and impose
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