外文翻译中英文-综采放顶煤的预测运作行为阶层和液压支架的最佳评

翻译部分英文原文PredictionofcavingbehaviorofstrataandoptimumratingofhydraulicpoweredsupportforlongwallworkingsAbstractAreliablepredictionofthecavingbehaviorofstrataandsupportcapacityrequirementforlongwallworkingshasalwaysbeenachallengeforrockmechanicsresearchersandmineplanningengineers.Itisveryimportantforsuccessfulplanningandimplementationofhighcapacitylongwallprojectstohaveproperselectionofsiteandcompatibleroofsupports,toensuresafeoperationoflongwallfaceespeciallyinmassiveanddifficulttocavestrataconditions.Thispaperillustratesanumericalmodelingbasedintegratedapproachforpredictingtheprogressivecavingbehaviorofstrataandoptimumcapacityrequirementofpoweredsupportforlongwallworkinginagivengeo-miningandstratacondition.Asetofdesigncriteriaforselectionofoptimalcapacitysupportintegratingthefieldexperienceandthenumericalmodelingresultsoflongwallpanels,operatedinawidelyvaryingstrataconditionsindifferentcoalfieldsofIndia.Casestudiesoftwotypicallongwallworkingsarepresentedtoassessthecavingbehaviorandsupportrequirementforsafeoperationoflongwallworkingunderthesitespecificregularandenmassecavingstrataconditions.Keywords:Longwall;Numericalmodeling;Progressivecaving;Optimalsupportcapacity;Faceconvergencegradient;enmassecaving;Dynamicloading;Rapidyieldvalve;Dischargecapacity;Responsetime1.IntroductionLongwallisagloballyprovenmassminingtechnologyforundergroundcoalmining.Thecomplexrockmechanicsissuesinvolvedinthisinflexibleminingsystemdemandscarefulplanningforselectionofsuitableminingsites,andrationalcapacitysupportsystemstoensuresuccessfulimplementationoftheprojectinagivengeo-miningandstratacondition.Thissubjectbearsutmostimportanceforthoseconditionswherethenaturalgenesisoftherockdoesnotfacilitateeasycavingofoverlyingstrataduringprogressiveminingofthecoalseam.MostofthecoalseamsinIndiaareoverlainbymassiveanddifficulttocavestrataformations.Theuncertainstratabehaviorintermsofuncontrolledroofcavingandfaceinstability,coupledwithdamageoffacesupports,hasbeenledtoamajorbottleneckinlarge-scaleadoptionoflongwalltechnologyundersuchstrataconditions.Forthesereasons,thepredictionofcavingbehaviorandsupportrequirementhasbeenamajortopicofresearchsincetheintroductionoflongwallfaces.Areliablepredictionofthecavingbehaviorofstratahelpsinselectionofsustainableminingparametersandrationalcapacityofsupports.Thedesignandoperationalparameterscanbeestablishedandtheireffectivenesscanbeevaluatedtoreducetheriskofuncertaintiesinplanninganddecisionmaking.Italsohelpsdevelopmentofasuitableandaneffectivemethodfordealingwiththedifficultcavingroof.Confidentuseofavailabletechnologyofroofsofteningbywaterinfusionorpre-blasting,orinductionofcavingbyhydro-fracturingorblastingingoafhasmadeitpracticallyfeasibletoextractalongwallfacesuccessfullyevenundermassiveroofconditions1,2and3.Although,anumberofmodelsandapproachesforpredictionofcavingbehaviorandsupportrequirementhavebeendevelopedindifferentcountries,theirapplicabilityinIndiangeo-miningconditionislimitedandsuffersfromconsiderablelacunaresultinginunreliableandinconsistentperformance4,5and6.Therearenumerousexampleswhereimproperplanninghasresultedinwrongsiteselectionandunder-ratedcapacityofsupportsgivingrisetoproblemssuchasthreatsoffaceinstability,frequentfacestoppages,irregularfaceadvance,poorfaceproductivityandcollapseofworkingsintheextremecases.Adetailedreviewofexistingapproachesandtheirperformanceindifferentfieldconditionsrevealthatalthoughtheexistingapproachesprovidesignificantcontributioninbetterunderstandingofthecomplexstratasupportinteraction,thereisstillamplescopefordevisingbetterapproachforassessmentofsupportcapacityrequirement7.Asthelongwallpanelsareequippedwithcostlyself-advancinghydraulicpoweredsupportsystems,decisionaboutapplicabilityoflongwallandselectionofanoptimalratingofsupportforagivenstrataandgeo-miningconditionareveryimportant.Thisisessentialforreducingthestratacontrolriskwhileplanningoflongwallworking,especiallyinthoseconditionswherethestrataaredifficulttocave.Therefore,developmentofasuitableapproachforpredictionofcavingbehaviorandoptimumsupportcapacityrequirementhasbecomeaprimenecessitywhichcanserveasaready-to-usetoolfortheminingindustry.Itwillhelptheindustryineffectivedecisionmakingforreliableplanningoflongwallworkingsinagivengeo-miningcondition.Earlier,theauthorsreportedanumericalmodelingapproach8toassessthecavingbehaviorofstrataandtheperformanceofhydraulicpoweredsupportwithprogressivefaceadvanceinlongwallworkinginagivenstratacondition.Italsoillustratedtheresultsofitsvalidationwithfieldexperienceof23differentlongwallpanelsoperatedindifferentcoalfieldsinIndia.Theauthorsalsocarriedoutaparametricstudy9toexaminetheeffectofcriticalparameterslikedepth,stratathickness,insituhorizontalstress,extractionheight,etc.onthecavingbehaviorandsupportperformanceinlongwallworkings.Theresultsofthisstudywasveryhelpfulinimprovingthepresentlevelofunderstandingoftheconditionbasedcavingmechanicsofstrataandperformanceofpoweredroofsupportinagivengeo-miningcondition.Italsoshowedthatinstallingastiffersupportindeepminingconditionmayleadtounnecessaryloadingwhichcanbeavoidedbyselectingasuitablesupportoflowerstiffnessfollowingthebasicsofsupportdesignusinggroundresponsecurve.Themodelobservationsforthedifferentlongwallpanelsshowsthatweightatthefaceisnotalwaysobservedduetofailureofmainroofespeciallywhentheimmediateroofisthicker.Inthiscase,theimmediateroofitselfactsasthemainroofandtheroleofimmediateroofgetsdifferentfromtheconceptualconsiderations.Thenumericalmodelingtoolobviatessuchconceptualconsiderationsandhenceismoreeffectiveinunderstandingthemechanismoffailureandcavingofstratainagivengeo-miningcondition.Theresultsalsorevealedthatlongwallpanelswereextractedinthefieldwithoutanyseverestrataproblem,whereregularcavingofstratawithpeakfaceconvergencegradientoflessthan75mm/moffaceadvancewasobservedinthenumericalmodel.However,increasedconvergenceatthefacewasobservedinthenumericalmodelofotherlongwallpanelswherethelongwallfacehadtobestoppedperiodicallytorecoverthedeterioratingroofconditionduetoexcessiveconvergenceatthefaceduringperiodsofmajorroofcaving.Instancesofenmassecavingwerealsoobservedinsomeofthelongwallpanels.Acommonmodelingobservationofthesepanelsisthatathicklayerofstrataprovidesaverypoortendencyofbendingandpreventsthetensilecrackfromprogressingsignificantlywithprogressivefaceadvance,leadingtoenmassefailureandcavingofstratainsuchcondition.Dynamicloadingonthesupportwasexperiencedwhileworkingthesefacesinthefield.However,thenumericalmodelingobservationofloadonsupportandfaceconvergencefortheseenmassecavingcaseswerenotrepresentativeoftheactualfieldcondition,asdynamicloadingresultsinmuchheavyloadingonthesupportcomparedtothevalueestimatedbythestaticnumericalmodel.Italsoindicatedforrequirementoffurtherstudytoproposeasuitableapproachwhichcouldbeintegratedwiththeresultsofthenumericalmodelingtoassessthedynamicloadduetoenmassecavingofstrataandtoestimatetherapidyieldvalverequirementtoensuresafeworkingofsupportsundersuchstrataconditions.Subsequently,amathematicalapproachintegratedtothenumericalmodeling10wasproposedtomeettheaboverequirement.Itcanbeusedtoassesstherequisitedischargerateandresponsetimeofrapidyieldvalvetorestrictthedynamicloadonsupportwithinpermissiblelimittoensuresafeandsustainableperformanceofthepoweredroofsupportduringprogressivefaceadvanceunderdynamicloadingconditions.Italsorecognizedthefactthatmerelyselectingahighercapacitysupportcannotguaranteesafelongwalloperationinsuchloadingcondition.Rapidyieldvalveofsuitableratingisrequiredtobefittedwiththesupportsforensuringsafetyofthesupportstructureandthelongwallfacewheredynamicloadingduetoenmassecavingofstrataisexpected.Thispaperillustratesanintegratedmodelingapproachtopredictthecavingbehaviorandoptimumratingofpoweredroofsupportsforsafeoperationoflongwallworkinginagivengeo-miningcondition.Theresultsofcavingassessmentmodelarefurtherextendedtoformulatesuitablesupportselectioncriteriaforregularaswellasenmassecavingstrataconditions.Themodelingresultsforpredictionofcavingbehaviorandoptimalsupportcapacityfortwotypicalstrataconditionsarealsoillustrated.Thefirstcasebelongstoaregularcavingstratacondition,whereasthesecondcasereferstoastrataconditionwhichwitnesseduncontrolledfailureofroofleadingtodynamicloadingandcollapseofthefacesupports.2.ExperiencesofstratacontrolinlongwallworkingsPoweredsupportlongwallworkingisunderoperationformorethanfourdecadesindifferentcoalfieldsofIndia,withitsfirstintroductioninMoonidihmineofJhariacoalfieldin1978.Thedatacompiledfordifferentpanelsundertheworkreportedinthispapershowsthatdepthofsuchworkedoutpanelsvariedfrom40to395m,whereastheextractionheightvariedfrom1.8to4.5m.Thecapacityofpoweredroofsupportdeployedatthefacesvariedfrom325to800t(Table1).Theroofofthelongwallpanelsmainlyconsistedofcoaltomassivesandstonehavingeasytodifficultcavingcharacteristics.Thecompressivestrengthofthestratavariedfrom8to43MPawithanaverageof27MPa,whereasthetensilestrengthofthestratavariedfrom1to6MPa,withanaverageof3MPa.TheRQDofthestratavariedfrom4098%,withanaverageof76%.Thelayerthicknessofthestratavariedfrom4to49mwithanaverageof16m.Ingeneral,thehighRQDandthicknessofthestrataindicatepresenceofmassiverockformationwhichexhibitsadifficultcavingbehaviorofroofatthelongwallfaces.Thecavingcharacteristicsofstrataarequiteinterestinginshallowdepthlongwallworkings.About10longwallfacesinRVIIseaminJhanjramineunderRaniganjcoalfieldwereextractedverysuccessfullyatadepthof4060m.However,acutestratacontrolproblemsduetointenseroofweightingduringperiodsofmajorroofcavingwasexperiencedduringlongwallextractionofPassangseaminBalrampurandNewKumdaminesunderBishrampurcoalfieldandinBurharVIBseamatRajendramineunderSohagpurcoalfieldwhileworkingatadepthof5080m.Thesevereloadatthefaceduringtheperiodsofmajorroofcavingwassubsequentlymanagedintheseworkingsbyblastingtheoverhungstrataingoaffromsurfaceatregularintervalwiththeprogressivefaceadvance.SomeofthelongwallpanelsinRVIIAcoalseamatdepthof100150minJhanjramine(inMainIndustrialComplexpart)wereworkedwithoutanyproblemwhereassomeotherpanelsworkedinanotherpatch(1and2Inclinepart)ofthesameseamexperiencedconsiderablestratacontrolproblemsduetoexcessivefaceconvergenceandresultantdeteriorationofroofduringperiodsofmajorroofcavings.TwolongwallfacesinSamlaseamatKhottadihmineinRaniganjcoalfieldwereextractedwithconsiderablestratacontrolproblematadepthof160190mwhilethethirdfacegotcollapsedafter791madvanceandtheworkingwasdiscontinued11.ThefirstlongwallfaceatChurchamineunderSonhatcoalfieldcollapsedafterafaceadvanceof198m12.Itused4680tImmediateForwardchockshieldsupportstoextract3mthickcoalseamVatadepthof218m.Thissitewastypicalduetopresenceof122mthickdoleritesillataheightof95.6mabovethecoalseam,whichwasfoundtobeintactatthetimeofcollapseoftheface.ThelongwalloperationsinGodavariValleycoalfieldhavebeenquitesuccessfulingeneral.Thecapacityofthesupportdeployedatthesefacesrangesfrom4360to4800tThegeneralviewaboutthecavingbehaviorofstrataintheseminesisthatintensityofroofweightisverylowwhileworkingunder67mthickeasilycavableimmediateroof.Theintensityofweightissignificantwherethepanelshavebeenworkedundersandstoneroofwithpoorcavingcharacteristics.Inthiscoalfield,facelengthhasbeenidentifiedasoneofthemostimportantinfluencingfactorstolimitloadatfaceduringcaving.Manyfacesofshorterlength(6090m)havebeenworkedsuccessfullyinJK5andVK7mineusing4360tchockshieldsupport.Earlier,lotofstratacontrolproblemhadbeenexperiencedwhileoperatinglongerfaces(120150mlength)inthesemines.Someofthefacesexperiencedconsiderablestratacontrolproblemwhentheirprogresshadtobestoppedduetomechanicalbreakdownofequipmentcoincidingwiththeperiodsofmajorroofcaving.AlongwallpanelinGDK9minewith3mextractionheightwasworkedsuccessfullyinbottomsectionofa10.5thickcoalseamusingfacesupportsof4360tcapacityleaving7.5thickeasycavingcoalintheimmediateroofwhereasanotherpanel(panel3T)intopsectionofthesamecoalseamcouldnotbeworkedundermassivesandstoneimmediateroofandhadtobeclosedduetounmanageableloadonthesupports.中文翻译综采放顶煤的预测运作行为阶层和液压支架的最佳评级摘要:对地层的运作和支持长壁综放行为能力可靠预测的要求一直是岩石力学研究人员和矿山规划工程师的挑战。这是非常成功的策划和高容量综采项目的实施有适当选择的网站和兼容屋顶支持，以确保综采工作面安全运行的重要，尤其是在巨大的洞穴地层条件下。本文说明了基于数值模拟预测地层逐步放顶液压支架及最佳容量的要求，为长壁行为在特定地质条件下开采和阶层工作的综合方法。一种优化整合能力方面的经验和综采板数值模拟的结果，在印度不同煤田广泛支持不同地层条件下工作选择一套设计标准。两种典型工作面运作案例研究来评估放顶煤开采行为和安全综采下的特定地点放定期和集体经营阶层支持的条件下工作的要求。1.简介引进长壁是全球探明地下煤炭开采量开采技术。复杂的岩石力学在这僵化挖掘系统涉及的问题要求认真筹划合适的矿址的选择，理性能力的支持系统，以确保在给定的地理条件，开采和阶层的项目的成功实施。本课题的条件下负有的自然成因的岩石不利于在本煤层开采覆岩逐步易放至关重要。在印度大部分煤层上覆以大量且难以洞穴地层单位。地层中的不确定行为失控顶板冒落，面对不稳定的条件，面对支持与损伤耦合，已导致了大规模的综采技术的应用在这样的地层条件发生的重大瓶颈。基于这些原因，放行为和支持需求预测以来引进的综采面的研究的主要课题。一种对综放行为的地层可靠的预测有助于可持续开采参数和支持合理的容量选择。设计和操作参数可以建立及其有效性进行评价，以减少在规划和决策的不确定性风险。它还可以帮助开发一个适合一个与放顶处理困难的有效方法。自信的屋顶使用现有技术软化注水或预爆破，或由水力压裂或炮采放采空区的诱导，使这实际上可行的成功提取综采工作面顶板条件，即使在大规模的12和3。虽然，一个模型和方法对放顶煤的行为和需求预测支持了一些在不同国家的发展，他们在印度的地质采矿条件的适用性是有限的，从相当大的不可靠造成的空白和不一致的表现受到45和6。其中有规划不当，导致错误的选址评估，如面对不稳定，经常面临停产，不规则面推进，贫困面生产力和运作崩溃的威胁，在极端的情况下被低估的问题引起许多例子支持能力。对现有方法进行详细审查和它们在不同条件下的性能方面透露，虽然现有的方法提供了更好的复杂地层支持相互作用的理解重大贡献，但仍然负责制定的支持能力需求评估7更好的方法用武之地。由于长壁面板与昂贵的自推进液压支架系统，约长壁和支持最佳等级的选择装备的适用性决定一个给定的地层和地质开采条件是非常重要的。这是为减少风险而岩层控制综采工作规划，特别是在那些条件下的地层难以洞穴，至关重要。因此，一个合适的方法的发展及对放行为和需求预测的最佳保障能力已成为一个首要的必要性，可以作为一个做好准备使用的为采矿业的工具。这将有助于在有效的运作决策综采可靠的规划编制中的一个给定的地质开采条件的产业。此前，作者报道的数值模拟方法8，以评估地层放行为和液压与进步面临提前支架在综表现在给定的地层下工作。这也说明与23个不同领域的长壁煤在印度不同领域的操作面板经验验证的结果。作者还进行了参数分析9研究的关键参数，如深度，地层厚度效应原位水平应力，提取高度等，在综采放顶煤行为和运作支持性能。这项研究的结果是非常在提高认识的条件有助于基于目前的水平在一个特定的地理放开采条件阶层和力学性能顶棚支持。它还表明，安装在深部开采条件下可能会导致不必要的负荷更严厉的支持，可以通过选择一个适当的支持下刚度使用地面以下的支持响应曲线设计的基本知识避免。对于不同的工作面面板模型的观察表明，在面对体重并不总是发现由于老顶失败，特别是当直接顶较厚。在这种情况下，直接顶本身作为主要的屋顶和直接顶的作用得到不同的概念考虑。数值模拟工具，省却这种概念上的考虑，因而是更了解地层的破坏机理及放在一个特定的地理条件，有效挖掘。研究结果还表明，长壁小组在外地没有任何严重的地层中提取的问题，在那里经常放地层与峰面小于75毫米收敛梯度/M的脸提前在数值模型观察。但是，在增加了在其他地方长壁综采工作面小组不得不停止定期回收过程中顶板冒落的重大顶板条件不断恶化的时期，由于过度趋同的面孔，观察面数值模型收敛。集体放的实例也观察到一些小组的工作面。对这些面板常用的建模观察是一层厚厚的阶层提供了一个非常贫穷的弯曲倾向，防止提前面对进步与进步显着拉裂，导致大批失败，在这种条件下地层放。支持动态负载量的工作经验，而这些在外地的面孔。但是，荷载数值模拟的支持，为这些案件集体放面不收敛观察领域的实际情况的代表，在很多情况相比，由静态数值模型估计值重载支持动态加载的结果。它还表示对进一步研究的要求，提出一个合适的做法，可能与数值模拟的结果，综合评估的动态负载由于大批地层放，并估计产量迅速阀门要求，以确保安全工作的支持在这样的地层条件。随后，数学方法融入了数值模拟10，提出了符合上述要求。它可用于评估必要的放电率和反应迅速的产量阀时间限制在允许限度的支持，以确保在动态负载动态负载条件下，面对逐步推进安全和可持续发展的动力屋顶支持性能。它也认识到这一事实，仅仅选择一个更高的容量支持不能保证在这种荷载条件下综采安全运行。适当的评价产量快速阀须安装与支持，以确保安全的支撑结构和综采工作面动态加载的地方，由于地层放集体预期。本文说明了一个综合的建模方法来预测放顶煤开采的行为，在特定的地理开采条件最佳的顶支撑评级为长综放工作面的安全运行。放顶考核模式的结果是进一步扩大到制定适当的支援，定期遴选标准以及集体放地层条件。放行为的两种典型地层条件下的最佳保障能力预测模拟结果还说明。第一个个案是属于经常放地层条件，而第二种情况是指地层条件，目睹了屋顶失控故