外文翻译以GIS为基础的煤矿开采沉陷危机分析.docx
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外文翻译以GIS为基础的煤矿开采沉陷危机分析
翻译部分
英文原文
SensitivityanalysisfortheGIS-basedmappingofthegroundsubsidencehazardnearabandonedundergroundcoalmines
AbstractGroundsubsidencearoundabandonedunder-groundcoalminescancausemuchlossoflifeandprop-erty.WeanalyzefactorsthatcanaffectgroundsubsidencearoundabandonedminesinJeongahminKangwon-dobysensitivityanalysisingeographicinformationsystem(GIS).Spatialdataforthesubsidencearea,topographyandgeologyandvariousgroundengineeringdatawerecol-lectedandusedtomakeafactorrasterdatabaseforagroundsubsidencehazardmap.Todeterminetheimpor-tanceofextractedsubsidence-relatedfactors,frequencyratiomodelandsensitivityanalysiswereemployed.Sen-sitivityanalysisisamethodforcomparingthecombinedeffectsofallfactorsexceptone.Sensitivityanalysisanditsverificationshowedthatusingallfactorsprovided91.61%accuracy.Thebestaccuracywasachievedbynotconsid-eringthegroundwaterdepth(92.77%)andtheworstbynotconsideringthelineament(85.42%).Theresultsshowthatthedistancefromthelineamentandthedistancefromthedrifthighlyaffectedtheoccurrenceofgroundsubsidence,andthegroundwaterdepth,landuseandrockmassrating
hadtheleasteffects.Thus,wedeterminedcausesofgroundsubsidenceinthestudyareaandthisinformationcouldhelpinthepredictionofgroundsubsidenceinotherareas.
KeywordsGISAbandonedundergroundcoalmineGroundsubsidenceFrequencyratioSensitivityanalysisKorea
Introduction
CoalindustryhasplayedamajorroleinthedevelopmentoftheKoreaneconomysincethe1960s.However,thecoalindustrybegantodeclinefromtheendofthe1980sbecausetheoilpricefellglobally.Therewere173coalminesin1988inJeongseon,Kangwon-do,thelargestcoalminingregioninKorea.However,valuelesscoalmineswereabandonedaftertheimplementationofcoalindustryrationalizationactionbyKoreangovernment.Today,nocoalminesareinoperation.IntheabandonedcoalminesinJeongseon,environmentalpollution,havingneverbeenconsideredafutureproblematthetimetheminesceasedoperating,isontheincrease.Heavymetalsinwastewaterfromcoalminesandmuckreachingriversandsoilisaseriousproblem.Inparticular,mostabandonedcoalminesareinmountainrangesandtheirdamagetotheenviron-mentisnotwidelyknown.Groundsubsidenceduetoanundergroundcoalmineisahazardtohumanlifeaswellastopropertysuchasrailways,roads,housesandbuildings.Inaddition,itisdifficulttocompletelyrecoveranareaofsubsidenceandrehabilitationisexpensive.Moreover,mostcountermeasuresforgroundsubsidencearesimplyrein-forcementsaftergroundsubsidencehasalreadyoccurred.Therefore,itisnecessarytohaveasystematicpredictionandmanagementplanforanareaofgroundsubsidence.Therehavebeenmanystudiesonthepredictionofgroundsubsidencelocationsandhowtodecreaserelateddamage.
Methodology
Ingeneral,topredictgroundsubsidenceitisnecessarytoassumethatsubsidenceoccurrenceisdeterminedbysub-sidence-relatedfactors,andthatfuturesubsidencewilloccurunderconditionsthatarethesameasthoseforpastsubsidenceaccordingtotherelativefrequencyconceptofprobabilitytheory.Onthisbasis,therelationshipbetweenareaswheresubsidencehasoccurredandsubsidence-rela-tedfactorscanbedistinguishedfromtherelationshipbetweenareaswithoutpastsubsidenceandsubsidence-relatedfactors.Inthiswork,thespatialrelationshipsbetweensubsidencelocationsandeachsubsidence-relatedfactorwereanalyzedusingthefrequencyratiowhichisoneoftheprobabilitymodels.Thefrequencyratioistheratiooftheareawheresubsidencehasoccurredtothetotalstudyarea,andisalsotheratiooftheprobabilityofsubsidenceoccurrencetonooccurrenceforagivenattribute.Inthecaseofsubsidenceoccurrence,ifthesubsidenceeventisdenotedBandagivenfactor’sattributeisdenotedD,thenthefrequencyratioofDistheratiooftheconditionalprobabilitiesofB.Therefore,thegreaterthisratio,thestrongertherelationshipbetweensubsidenceoccurrenceandthegivenfactor’sattribute.Thefrequencyratiowascalculatedforeachfactortypeorrangethathadbeenidentifiedassignificantwithrespecttocausinggroundsubsidence.Theratioswereusedforcalculatingthegroundsubsidencehazardindex(GSHI)andmapping.TherehavebeenafewstudiescarriedoutongroundsubsidencehazardevaluationsusingthefrequencyratioandaGIS;forexample,Kimetal.(2006)introducedtheanalysisofgroundsubsidencehazardandsummarizedmanygroundsubsidencehazardevolutionstudies.
DiagramspresentedinFig.4showthestepsforcalcu-latingthefrequencyratio:
(a)findinglocationsofgroundsubsidence,(b)representingcellsofclass1forfactorAand(c)describingtheareaofspatialoverlapforareasofsubsidenceandareasofclass1forfactorA.Inthepresent
exampleinwhichthestudyareacomprises64cells,thereare23groundsubsidencecellsand19cellsthatareofclass1forfactorA.Thereare12cellsofsubsidencethatarealsocellsofclass1forfactorA.Thepercentagesforsubsidenceareawithrespecttoclass1forfactorAandtheentiredomainare52.17and29.69%,respectively.Therefore,thefrequencyratioofclass1forfactorAis52.17/29.69%=1.76.
Sensitivityanalysis
Sensitivityanalysesshowhowasolutionchangeswhentheinputfactorsarechanged.Iftheselectionofafactorresultsinarelativelylargechangeintheoutcome,thentheout-comeissaidtodependonthatfactor.Sensitivityanalysisquantifiestheuncertaintyofeachfactor.Thefactorsthathavethegreatestimpactonthecalculatedsubsidencehazardmapcanthereforebeidentified.
Sensitivityanalysesmodelbehaviorbydeterminingtherateofchangeinthemodeloutputasparametersorinputdataarevaried,thusgivinganunderstandingofhowchangesintheinputsinfluencetheoutput.Suchanalysesexplainhowinputsaffecttheoutputandquantifythestrengthsoftheinputsfromthevariationsintheoutput.Sensitivityanalysishasbeenappliedinavarietyofstudies.ArhonditsisandBrett(2005)introducedprocessformula-tionsandsensitivityanalysisforacomplexeutrophicationmodelofLakeWashington,USA.Jooetal.(1998)repre-sentedthesensitivityoftheleachateleveltoreducethehighleachatelevelinlandfill.Sensitivityanalysishasbeenappliedtolandslidesusceptibilityhazardmapping(LeeandTalib2005).Inthepresentstudy,thesensitivityanalyseswereconductedtodeterminefactorsinvolvedingroundsubsidence.Toextractsubsidence-relatedfactors,thefre-quencyratiomodelandsensitivityanalysiswereemployed.Thesensitivityanalysiscomparedtheeffectsofallfactorsexceptone.
Data
Manystudieshaveidentifiedimportantfactorsthatcon-tributetogroundsubsidencearoundcoalmines(e.g.Waltham1989;CoalIndustryPromotionBoard1997),includingthedepthandheightofminecavities,excavationmethod,degreeofinclinationoftheexcavation,scopeofmining,structuralgeology,flowofgroundwaterandthemechanicalcharacteristicsrepresentedbytherockmassrating(RMR).
Inthisstudy,locationsofgroundsubsidenceandfactorsgoverningtheoccurrenceofgroundsubsidencewerecol-lectedinavector-typespatialdatabaseandthenrepre-sentedonagridusingtheArcGISsoftwarepackage.ThespatialdatabaseisshowninTable1.Thedatabaseincludeda1:
5,000groundsubsidencemap,1:
50,000geologicalmap,1:
5,000topographicmap,1:
5,000landusemap,1:
1,200minetunnelmap,boreholedataandsatelliteimagerywith1mresolution.ThesiteJeongahmwaschosenforinvestigationinthisstudy.ReliableaccuracyofthespatialdatabaseisindispensableinaGISenvironment.Forthisreason,accuratemapsauthorizedbynationalorganizationssuchastheCoalIndustryPromotionBoardforgroundsubsidence,theNationalGeographicInforma-tionInstitutefortopographyandlanduse,theMineRec-lamationCorp.forminetunnelsandboreholesandtheKoreaInstituteofGeoscienceandMineralResourcesforgeologywereassembledeventhoughthescalesofthemapsdiffered.
EightvariablesasshowninFig.5,extractedfromtheconstructedspatialdatabase,wereconsideredasfactorsofgroundsubsidencewhencalculatingtheprobability.Con-tours(5mintervals)andsurveybasepointsofelevationwereextractedfromthetopographicmap,andtriangu-latedirregularnetworkwasmadeusingtheelevations.Theangleofslopewasobtainedfromthedigitalelevationmap.Areasofbuildings,mountains,railways,fields,rivers,hybrids,roadsandmiscellaneoususewereextractedfromthelandusemap.Mostliteraturestatesthatthemajorfactoringroundsubsidenceisthescopeofminecavities.Therefore,constructingadatabaseforthedepthsandwidthsofminecavitieswasimportant.Toachievethis,
(1)GPSmeasurementswereusedtodeterminetheexactpositionsofmineheads,
(2)thesepositionswereusedtovectorizeahardcopyoftheminetunnelmapand(3)thevectorizedminetunnelmapwasconvertedtoanASCIIgridfileandsubtractedfromthedigitalelevationmaprasterdata.Therewere13boreholesatthestudysite,butfourboreholesdidnothaveRMRvaluesandgroundwaterlevels.Aninverse-distanceweightinginterpolationwasusedtocontourtheRMRandgroundwaterlevel.Geolog-icaldatawereextractedfromthe1:
50,000geologicalmap.AlineamentwasdetectedfromIKONOSimagerywith1-mresolutionbyastructuralgeologist.Thedistancefromthelineamentwascalculatedat1-mintervalsusingtheEuclideandistancemethod.Thefactorswerethenrepre-sentedby2m92mc