1、Designation: D6026 06D6026 13Standard Practice forUsing Significant Digits in Geotechnical Data1This standard is issued under the fixed designation D6026; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A
2、 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 practice is intended to promote uniformity in recording significant digits for measured and calculated values involvinggeotechni
3、cal data. The guidelines presented are industry standard, and are representative of the significant digits that shouldgenerally be retained. The guidelines do not consider material variation, purpose for obtaining the data, special purpose studies,or any considerations for the users objectives; and
4、it is common practice to increase or reduce significant digits of reported datato be commensurate with these considerations. It is beyond the scope of this practice to consider significant digits used in analysismethods for engineering designdesign.1.1.1 Using significant digits in geotechnical data
5、 involves the processes of collecting, calculating, and recording eithermeasured values or calculated values (results), or both.1.2 This practice accepts a variation of the traditional rounding method that recognizes the algorithm common to most hand-heldcalculators, see 5.2.3. The traditional round
6、ing method (see 5.2) is in accordance with Practice E29 or IEEE/ASTM SI 10.1.3 This practice offers a set of instructions for performing one or more specific operations. This document cannot replaceeducation or experience and should be used in conjunction with professional judgment. Not all aspects
7、of this practice may beapplicable in all circumstances. This ASTM standard is not intended to represent or replace the standard of care by which theadequacy of a given professional service must be judged, nor should this document be applied without consideration of aprojectsprojects many unique aspe
8、cts. The word “Standard” in the title of this document means only that the document has beenapproved through the ASTM consensus process.2. Referenced Documents2.1 ASTM Standards:2D653 Terminology Relating to Soil, Rock, and Contained FluidsD2905 Practice for Statements on Number of Specimens for Tex
9、tiles (Withdrawn 2008)3D4356 Practice for Establishing Consistent Test Method Tolerances (Withdrawn 2007)3D6913 Test Methods for Particle-Size Distribution (Gradation) of Soils Using Sieve AnalysisE29 Practice for Using Significant Digits in Test Data to Determine Conformance with SpecificationsE344
10、 Terminology Relating to Thermometry and HydrometryE456 Terminology Relating to Quality and StatisticsE833 Terminology of Building EconomicsIEEE/ASTM SI 10 Standard for Use of the International System of Units (SI): The Modern Metric System3. Terminology3.1 Definitions:3.1.1 For common definitions o
11、f soil and rock terms in this standard, refer to Terminology D653.3.2 Definitions:Definitions of Terms Specific to This Standard:3.1.1 For common definitions of soil and rock terms in this standard, refer to Terminology D653.3.2.1 accuracy, accuracynthe degree of agreement of an individual measureme
12、nt or average of measurements with anaccepted reference value, or level. See closeness of agreement between a test result and an accepted reference value. (SeeTerminology E344E456 - 97.)1 This practice is under the jurisdiction of ASTM Committee D18 on Soil and Rockand is the direct responsibility o
13、f Subcommittee D18.91 on Standards Developmentand Review.Current edition approved Nov. 1, 2006Nov. 1, 2013. Published December 2006 December 2013. Originally approved in 1996. Last previous edition approved in 20012006as D602601 e1. DOI: 10.1520/D6026-06. 06. DOI: 10.1520/D6026-13.2 For referencedAS
14、TM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.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
15、of an ASTM standard 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 p
16、ublished by ASTM 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 States13.2.2 calculated value, nthe resulting value determined by pro
17、cessing measured value(s) using an equation. See PracticeD4356 - 84(Reapproved 1996).3.2.2.1 DiscussionIn many cases the calculated value(s) is considered a determination value(s).3.2.3 determination value, nthe numerical quantity calculated by means of the test method equation from the measurementv
18、alues obtained as directed in a test method. See Practice D4356 - 84(Reapproved 1996).3.2.4 measurement value, nthe resulting value determined by measuring a dimension, quantity, or property.3.2.4.1 DiscussionIn many cases the term “measured value(s)” is also referred to as “measurement value(s)”. S
19、ee Practice D4356 - 84(Reapproved1996).3.2.5 precision, nthe closeness of agreement between independent test results obtained under stipulated conditions. See(SeeTerminology E456 - 96. 08.)3.2.5.1 DiscussionPrecision depends on random errors and does not relate to the true or specified value.3.2.5.2
20、 DiscussionThe measure of precision usually is expressed in terms of imprecision and computed as a standard deviation of the test results. Lessprecision is reflected by a larger standard deviation.3.2.5.3 Discussion“Independent test results” means results obtained in a manner not influenced by any p
21、revious result on the same or similar testobject. Quantitative measures of precision depend critically on the stipulated conditions. Repeatability and reproducibilityconditions are particular sets of extreme conditions.3.2.6 rounding, nthe process of reducing the number of digits in a number accordi
22、ng to rules relating to the required accuracyof the value.3.2.7 significant digitany of the integers one through nine and zeros except leading zeros and some trailing zeros.3.2.7.1 Zero is a significant digit if it comes between two non-zero integers.3.2.7.2 Zeros leading the first nonzero digit of
23、a number indicate the order of magnitude only and are not significant digits. Forexample, the number 0.0034 has two significant digits.3.2.7.3 Zeros trailing the last nonzero digit for numbers represented with a decimal point are significant digits. For example,4.00 and 4.01 have three significant d
24、igits.3.2.7.4 The significance of trailing zeros for numbers represented without use of a decimal point can only be identified fromknowledge of the source of the value.3.2.8 sensitivity analysis, na test of the outcome of an analysis by altering one or more parameters from an initially assumedvalue(
25、s). (See Terminology E833 09a.)3.2.8.1 DiscussionSensitivity analyses are often related to the design process, but not exactly applied in that design process. A sensitivity analysismight include how measured shear strength or hydraulic conductivity varies with molding water content and percent compa
26、ction.3.2.9 test result, nthe value obtained by applying a given test method, expressed as a single determination or a specifiedcombination of a number of determinations. See Practice D2905 - 91.3.2.10 variability analysis, nthe determination of the variation in values within a given boundary condit
27、ion(s)3.2.10.1 DiscussionD6026 132A variability analysis might include how a given property varies with depth.3.2 Definitions of Terms Specific to This Standard:3.2.1 sensitivity analysis, na test of the outcome of an analysis by altering one or more parameters from an initially assumedvalue(s). See
28、 Terminology E833 - 97b.3.2.1.1 DiscussionSensitivity analyses are often related to the design process, but not exactly applied in that design process. A sensitivity analysismight include how measured shear strength or hydraulic conductivity varies with molding water content and percent compaction.3
29、.2.2 variability analysis, nthe determination of the variation in values within a given boundary condition(s)3.2.2.1 DiscussionA variability analysis might include how a given property varies with depth.4. Significance and Use4.1 The guidelines presented in this practice for retaining significant di
30、gits and rounding numbers may be adopted by the usingagency or user. Generally, their adoption should be used for calculating and recording data when specified requirements are notincluded in a standard.4.2 The guidelines presented herein should not be interpreted as absolute rules but as guides to
31、calculate and report observedor test data without exaggerating or degrading the accuracy of the values.4.2.1 The guidelines presented emphasize recording data to enough significant digits or number of decimal places to allowsensitivity and variability analyses to be performed, see 3.2.5. Guidelines
32、for Rounding Numbers in Calculating and Recording Data5.1 General DiscussionRounding data avoids the misleading impression of precision while preventing the loss of informationdue to coarse resolution. Any approach to retention of significant digits of necessity involves some loss of information; th
33、erefore,the level of rounding should be selected carefully considering both planned and potential uses for the data. See(See Practice E29)5.2 Rounding NumbersWhen a numerical value is to be rounded to fewer digits than the total number available, use thefollowing procedure which is in accordance wit
34、h Practice E29 or IEEE/ASTM SI 10:When the first digitbeyond the last placeto be retained is:The digit in the lastplace retained is: Examples5 increased by 1 2.464 to 2.5Exactly 5 increased by 1 2.55 to 2.6if it is odd orunchanged if it is even 2.45 to 2.45 followed only same as above 2.5500 to 2.6b
35、y zeros for exactly 5 or2.4500 to 2.45.2.1 The rounded value should be obtained in one step by direct rounding of the most precise value available and not in twoor more successive rounding steps. For example, 89 490 rounded to the nearest 1000 is at once 89 000. It would be incorrect toround first t
36、o the nearest 100, giving 89 500 and then to the nearest 1000, giving 90 000.5.2.2 The same rule applies when rounding a number with many digits to a number with a few digits as occurs when using acomputer or calculator that displays the answer to a computation as ten or more digits and the answer i
37、s to be recorded to a fewdigits. For example, the number 2.34567 rounded to two significant digits would be 2.3.5.2.3 Calculators and computers, in general, do not follow all the rules given in 5.2, (that is, only rounding up odd digitsfollowed by a five, while even digits stay the same (2.55 to 2.6
38、 or 2.45 to 2.4) and generally always round up. Recognizing thewidespread use of calculators and computers that always round up, their use shall not be regarded as nonconforming with thispractice.5.2.4 The numbers to be reported are rounded at the end of calculations to the appropriate number of sig
39、nificant digits, not priorto the calculationscalculations. (See section 5.4)5.3 Recording Measured DataWhen recording measured values, as in reading marks on a burette, ruler, or dial, record alldigits known exactly, plus one digit, which may be uncertain due to estimation.5.3.1 When the measuring d
40、evice has a vernier scale, record the last digit from the vernier.5.3.2 The number of significant digits given by a digital display or printout from an instrument should be greater than or equalto the sensor to which it is connected. Care should be taken not to record digits beyond the precision of
41、the sensor, however. ForD6026 133example, using a pressure transducer with the precision of 1 kPa should not be read to the nearest 0.1 kPa because the readabilityof the output instrument displays more digits.5.4 Calculation of Measured DataWhen using measured values to produce a calculated value(s)
42、, avoid rounding ofintermediate quantities. As far as practicable with the calculation device or data sheet/form used, or both, carry out calculationsexactly as they occur (no reduced digits) and round the final value/result.5.5 Recording DataThe recorded data should conform to instructions in the r
43、espective standards. For example, the computedwater content values used in determining the liquid and plastic limits of a soil are recorded on the data sheet/form to the nearest0.1 %, see Table A1.1Table A1.1. . While the liquid and plastic limits are recorded, reported, or summarized to the nearest
44、 wholenumber and the percent designation is omitted.5.5.1 If the number of significant digits or number of decimal places in the measured and calculated value(s) is not specifiedin the respective standard, then one may use the following approach. Use TableTable A1.1 A1.1 to determine the number ofsi
45、gnificant digits or number of significant digits or number of decimal places in the calculated value(s). Using that value(s) andthe rules of significant digits as described in Section 6, determine the required significant digits or number of decimal places forthe measured value(s).5.5.2 If a standar
46、d has a conflict between the measured and calculated value(s) related to significant digits or number of decimalplaces, then use the following criterion. The criterion specified for calculated value(s) should govern how the measured value(s)is determined and recorded.6. Guidelines for Retaining Sign
47、ificant Digits in Calculating and Recording Data6.1 Upon completion of mathematical calculations, use the following rules as guidelines to determine the proper number ofsignificant digits or decimal places of rounded numbers.6.1.1 The rule when multiplying or dividing is that the result shall contai
48、n no more significant digits than the value with thesmaller number of significant digits. Examples include:6.1.1.1 11.38 4.3 = 49, since the factor 4.3 has two significant digits.6.1.1.2 Determine the volume, V, of an object having a base area, A, of 28.48 in.2 and a height, h, of 6.12 in., V = Ah =
49、 (28.48in.2) (6.12 in.) = 174, the answer to three significant figures in agreement with the height measurement.6.1.2 The rule when adding or subtracting data is that the number of decimal places in the result is the same as in the numbercontaining the fewest digits following the decimal. Examples include:6.1.2.1 11.24 + 9.3 + 6.32 = 26.9, since the last significant digit of 9.3 is the first following the decimal place, and 26.9 resultsby rounding the exact sum, 26.86.6.1.2.2 (926 923.4) = 3.6.1.2.3 (926 923.4) (926x 11.38 x 4.68/2.00 =
