ASTM_D_5924_-_96_2010.pdf

Designation:D592496(Reapproved 2010)Standard Guide forSelection of Simulation Approaches in Geostatistical SiteInvestigations1This standard is issued under the fixed designation D5924;the number immediately following the designation 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()indicates an editorial change since the last revision or reapproval.INTRODUCTIONGeostatistics is a framework for data analysis,estimation,and simulation in media whosemeasurable attributes show erratic spatial variability yet also possess a degree of spatial continuityimparted by the natural and anthropogenic processes operating therein.The soil,rock,and containedfluids encountered in environmental or geotechnical site investigations present such features,and theirsampled attributes are therefore amenable to geostatistical treatment.Geostatistical simulationapproaches are used to produce maps of an attribute that honor the spatial variability of sampledvalues.This guide reviews criteria for selecting a simulation approach,offering direction based on aconsensus of views without recommending a standard practice to follow in all cases.1.Scope1.1 This guide covers the conditions that determine theselection of a suitable simulation approach for a site investi-gation problem.Alternative simulation approaches consideredhere are conditional and nonconditional,indicator andGaussian,single and multiple realization,point,and block.1.2 This guide describes the conditions for which the use ofsimulation is an appropriate alternative to the use of estimationin geostatistical site investigations.1.3 This guide does not discuss the basic principles ofgeostatistics.Introductions to geostatistics may be found innumerous texts including Refs(1-3).21.4 This guide is concerned with general simulation ap-proaches only and does not discuss particular simulationalgorithms currently in use.These are described in Refs(4-6).1.5 This guide offers an organized collection of informationor a series of options and does not recommend a specificcourse of action.This document cannot replace education orexperience and should be used in conjunction with professionaljudgment.Not all aspects of this guide may be applicable in allcircumstances.This ASTM standard is not intended to repre-sent or replace the standard of care by which the adequacy ofa given professional service must be judged,nor should thisdocument be applied without consideration of a projects manyunique aspects.The word“Standard”in the title of thisdocument means only that the document has been approvedthrough the ASTM consensus process.2.Referenced Documents2.1 ASTM Standards:3D653 Terminology Relating to Soil,Rock,and ContainedFluidsD5549 Guide for The Contents of Geostatistical Site Inves-tigation Report(Withdrawn 2002)4D5922 Guide for Analysis of Spatial Variation in Geostatis-tical Site InvestigationsD5923 Guide for Selection of Kriging Methods in Geostatis-tical Site Investigations3.Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 conditional simulation,na simulation approachwhere realizations of the random function model are con-strained by values at sampled locations.3.1.2 drift,nin geostatistics,a systematic spatial variationof the local mean of a variable,usually expressed as apolynomial function of location coordinates.1This guide is under the jurisdiction ofASTM Committee D18 on Soil and Rockand is the direct responsibility of Subcommittee D18.01 on Surface and SubsurfaceCharacterization.Current edition approved May 1,2010.Published September 2010.Originallyapproved in 1996.Last previous edition approved in 2004 as D592496(2004).DOI:10.1520/D5924-96R10.2The boldface numbers in parentheses refer to a list of references at the end ofthe text.3For referenced ASTM standards,visit the ASTM website,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.4The last approved version of this historical standard is referenced onwww.astm.org.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 3.1.3 field,nin geostatistics,the region of one-,two-orthree-dimensional space within which a regionalized variableis defined.3.1.4 indicator variable,na regionalized variable that canhave only two possible values,zero or one.3.1.5 kriging,nan estimation method where sampleweights are obtained using a linear least-squares optimizationprocedure based on a mathematical model of spatial variabilityand where the unknown variable and the available samplevalues may have a point or block support.3.1.6 nonconditional simulation,na simulation approachwhere realizations of the random function model are uncon-strained by sample data.3.1.7 nugget effect,nthe component of spatial varianceunresolved by the s