毕业设计英文翻译爆破在岩巷掘进中的应用及井巷支护_精品文档Word文档格式.doc
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毕业设计英文翻译爆破在岩巷掘进中的应用及井巷支护_精品文档Word文档格式.doc
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SHAFTANDDRIFTEXCAVATIONBYBLASTING@#@ANDSHAFTSUPPORT@#@1APPLICATIONOFBLASTINGINSHAFTANDDRIFTEXCAVATION@#@1.1FRAGMENTATION@#@Fragmentationisthebreakingofcoal,ore,orrockbyblastingsothatthebulkofthematerialissmallenoughtoload,handleandtransport.Fragmentationwouldbeatitsbestwhenthedebrisisnotsmallerthannecessaryforhandlingandnotsolargeastorequirehandbreakingorsecondaryblasting.@#@Energymustbesuppliedtorockbydirectorindirectmeanstofragmentthatrockandthetypeofloadingsystem.Fragmentationenergyisconsumedbythemainmechanisms:
@#@
(1)creationofnewsurfacearea(fractureenergy),
(2)friction(plasticity)and(3)elasticwaveenegydispersion.@#@Theloadingmethoddeterminestherelativeproportionsandtheamountofenergyconsumedinfragmentingagivenrocktype.Unonfinedtensilefailureconsumestheleastenergywithanincreasinga,mountofenergyrequiredastherockismorehighlyconfinedwithinacompressivestressfieldduringfragmentationThewayenergyisappliedbytoolstocauserockormineralfragmentationisimportantindeterminingfragmentationefficiency.Tobestdesignfragmentationtoolsandoptimizefragmentationsystemsitwouldbedesirabletoknowhowrockpropertiesinfluencebreakage.@#@Thestrengthofrockisinfluencedbytheenvironmentalconditionsimposedontherock.Thoseofmostimportanceinrockare
(1)confiningpressure,
(2)porefluidpressure,(3)temperatureand(4)rateofloadapplication.Increaseinconfiningpressure,aswithincreasingdepthbeneaththearth'@#@ssurfaceorundertheactionofafragmentationtool,causesanincreaseinrockstrength.Apparentrockstrengthdecreasesasporcfluidpressureincreases,sinceitdecreasestheeffectofconfiningpressure.Althoughchemicaleffectsofporefluidsinfluencerockstrength,theygenerallyaresmallcomparedtotheconfiningpressureeffect,exceptforasmallminorityofrocktypes.Increaseinrocktemperaturecausesadecreaseinrockstrength.Thiseffectisverysmallbecauseofthesmallambienttemperaturechangesfoundduringmining.Anincreaseinrateofloadapplicationcausesanapparentincreaseinrockstrength.@#@Rockexhibitsdirectionalpropertiesthatinfluencethewayitbreaks.Theseareembodiedintheconceptofrockfabric,whichconnotesthestructureorconfigurationoftheaggregatecomponentsaswellasthephysicalormechanicalpropertymanifestations.Rockfabricontonlyrelatestothepreferredorientationofmineralconstituentsandtheirplanesofweakness,butalsototheconfigurationofdiscontinuities,microcracksandpores.Jointsandbeddingplaneshavegreatinfluenceonfragmentationatfieldscale.@#@Physicalpropertiesofrock(density,indentation,hardness,abrasivehardnessandporosity,)arefrequentlyusedinconjunctionwithmechanicalpropertiestodevelopbetterempiricalestimationsofrockfragmentation.@#@1.2BLASTHOLECHARGINGMETHODS@#@Drillholechargingcanbecarriedoutindifferentwaysdependingonwhethertheexplosiveusedisincartridgesorintheformofloosematerial.Theoldestchargingmethodimpliestheuseofatampingrodandthissystemisstillusedtoaverygreatextent.Duringthelast20years,compressedairchargershavebeenusedandthesemachinesprovidebothgoodcapacityandalsoanimprovedlevelofchargeconcentrationsothatthedrillholesareutilizedtoahigherdegree.Duringthelastfewyearssemi-automaticchargershavebeentakenintouse,primarilyinundergroundwork.Compressedairchargersforblastingpowderintheformofloosematerialhavealsocomeintouseonalargescale.Asfarasslurryblastingisconcerned,specialpumpingmethodshavebeendevelopedthroughwhichchargingcapacityinthecaseoflargediameterdrillholesispracticallygood.@#@Atampingrodmustbemadeofwoodorplastic.Itmustnotbetoothickinrelationtothedrillholediametersincethiscancrushanddamagefuseorelectricdetonatorcablesduringchargingwork.Ifagooddegreeofpackingistobeobtainedduringchargingwithatampingrodthenonlyonecartridgeatatimeshouldbechargedandtamped.Thedetonatormustbecorrectlyfedintothedrillholeduringchargingwork.@#@CompressedairchargershavebeeninuseisSwedenforabout20years.Thefirsttypeconsistedofaluminumpipesconnectedtogetherandthecartridgeswereblownintotheholewithanairpressureof42poundspersquareinch.sincethattimethechargingtubehasbeenreplacedbyanti-statictreatedplastichoseofaspecialdesign.Achargerincludesafoot-operatedvalve,reductionvavlewithairhose,breech,connectingtubeandcharginghose.@#@Thesemi-automaticchargerpermitsthecontinuousinsertionofexplosivecartridgeatthesamerateastheyarechargedintheholebythehose.Insteadofavalvebeingused,thecartridgespassthroughanairlockbetweent
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