矿业科学学报

Confining pressure effect on energy parameters of sandstones based on damage evolution

ChengHongming, YangXiaobin, LiuJunjia, ChenXunlu

2020, 5(3): 249-256.

Abstract(583) PDF(174)

Abstract:
Thecharacteristicparameterscorrespondingtodamageevolutionstateofrockmaterialarecrucialtodesigning,predictingandmonitoringthestabilityofgeotechnicalengineering.Thecyclicloadingunloadingtriaxialcompressiontestsofsandstoneswereimplementedwithdifferentconfiningpressure,and thedamage evolution state were determined by the lateral strain method and the volumetric strain method,andtheenergyparametersphasedevolution,theenergyevolutionofcharacteristicpointscorrespondingtodamageevolutionstateandrelationwithconfiningpressure,wereanalyzedbasedondamage evolutionstate.Theresultshowedthat:withdifferentconfiningpressure,theenergyparametersincreased withtheincreaseofthestrainateachstagebeforethepre-peak;themutationoftheelasticstrainenergy andthedissipationenergyatpeakstresstransferredtopost-peakwiththeincreaseoftheconfiningpressure;theenergyparametersdecreasedtoleveloffatresidualstressstage.Theenergyparametershada powerfunctiondecreasewithconfiningpressureatthepointofσcc,andthedissipationenergydecreased toleveloffwiththeincreaseoftheconfiningpressure.Atthepointsofσci,σcdandσp,theenergyparametersincreasedlinearlywithconfiningpressure,andtherewassmallchangetrendofthedifferencebetweenthetotalinputenergyandtheelasticstrainenergywiththeconfiningpressureatthedifferentcharacteristicpoints,andtherelativedifferencebetweenthetotalinputenergyandtheelasticstrainenergywas minimum,andthetotalinputenergyconvertedintotheelasticstrainenergywasmaximumatpointσcd.

Influence of atmospheric pressure change on gas sampling in mine closed area

LeiBaiwei, DuPeiying, XiaoBowen, WuBing

2020, 5(3): 257-262.

Abstract(505) PDF(127)

Abstract:
The variation of atmospheric pressure will cause the exchange of air volume between the closedareaofthemineandtheexternalenvironment,whichwillhaveanimpactonthegasmigrationin theclosedareaofthemine.Inordertostudytheinfluenceofthechangeofsurfaceatmosphericpressure onthegassamplingintheclosedareaofthemine,astatisticalanalysiswascarriedoutbasedonthe hourlyatmosphericpressuredatafrom2017to2018inDatongarea,andtheperiodicchangeruleofatmosphericpressure,thedistributiontimeofthepeakandtroughofthewaveandthechangeruleofthe leakage air volume in the closed area were determined.The results show that the variation of atmosphericpressure has annual periodicity,but the daily periodicity is poor,and it has a great influenceontheairvolumeexchangebetweentheclosedareaandtheexternalenvironment.Therefore, inordertoeffectivelyanalyzetheclosedareaoftherealgasstate,priorityshouldbegiventotheuseof tubesystemforcontinuoussamplingmonitoringanalysisofclosedarea.Atthesametime,theburied pipedepthshouldbedeterminedaccordingtothespecificparametersoftheclozedareaandthehourly variationlawoflocalatmosphericpressure,soastoeliminatetheinfluenceofairleakagefromtheexternalenvironmentonthedilutionofgasintheclozedarea.

Experimental study on the law of CO production in coal seam drilling

TanBo, ChengGang, ZhuXiaoman, XuBing

2020, 5(3): 263-271.

Abstract(513) PDF(70)

Abstract:
Drillingoperationiswidelyusedinmoderncoalmineoperation.Carbonmonoxidegas(CO) isproducedincoalseamduringdrillingoperation,whichleadstofireandCOexceedingaccident.In thispaper,anexperimentalplatformformonitoringCOincoalboreholeisbuiltandFourierinfrared spectroscopyiscarriedouttoanalyzethelawofproductionCOincoalseamduringdrillingfrommacroscopicandmicroscopicperspectives.TheexperimentalresultsshowthatthereisacertainamountofCO generatedinthecoalseamdrillingoperation,andtheproductionofCOisproportionaltothespeedand temperatureofthedrillbit.Inthecoalsamplecuttingsafterdrilling,thecontentsofaliphaticgroupand oxygen-containingfunctionalgrouparehigherthantherawcoal,indicatingthattheproductionrateof COishigherthantheconsumptionrate.AnalysisshowsthattheCOproducedduringdrillingoperation isamixtureofoxidizedcarbonmonoxide(O-CO)andcarbonmonoxide(S-CO)produced by the crackingofcoalmacromolecules.Amongthem,theO-COgeneratedduringdrillingoperationmainly comesfromoxygen-containingfunctionalgroupsformedbyoxidationofaliphaticfunctionalgroupssuch as—CH2and—CH3,andpyrolysisoccursundertheactionofinternalenergy.S-COiscausedbycoal*s macromolecularfractureandtheconversionofmechanicalenergytothermalenergy,leadingtothepyrolysisofoxygen-containingfunctionalgroupsinrawcoal.

Experimental study on combustion and extinguishing of secondary oxidation coal

ZhangYang, WuBing, LiTengteng, LeiBaiwei

2020, 5(3): 272-277.

Abstract(481) PDF(109)

Abstract:
Thespontaneouscombustionofcoalinthegoaf,whichbelongstosecondaryoxidationcoal seriouslythreatens the safe production of coal mines.Nitrogen can be used as a fire extinguishing agenttoinhibitspontaneouscombustionofresidualcoal.Inordertostudytheeffectofnitrogenonsecondary oxidation coal,thermogravimetric analysis and temperature programmed system are used to carryoutexperimentsonandanalysisofheatingprocessandextinguishingprocess.Duringtheheating process,astheconcentrationofnitrogenincreased,thecharacteristictemperaturesincreased,andnitrogen inhibited the combustion of secondary oxidation coal.In the process of cooling and extinguishingfire,thetemperatureandindicatorgasCOconcentrationwereusedasmonitoringparameterstotestthefireextinguishingeffect.Theanalysisshowsthatwhenamixtureofnitrogenandair withtheratioof50% /50%,wasintroducedintothesecondaryoxidationcoalprogrammedto400℃, thetimewasreducedby38.0% comparedwiththenaturaltemperaturedrop,alsothetimeforCO concentrationtodropto0wasshortenedby42.1%.Thehigherthenitrogenconcentration,theshorter thefire-extinguishingtimeofthesecondaryoxidationcoal,andthelesstheproductproduced,thebetterthefire-extinguishingeffect.

Comparative experimental study on deformation and damage characteristics of single coal rock and primary coal-rock combination

CaiYongbo, WangKai, XuChao

2020, 5(3): 278-283.

Abstract(547) PDF(109)

Abstract:
Thestudyofthedeformationandfailurelawsintheloadingprocessofcoal-rockcombination samplesareveryimportanttorevealthedynamicmechanismofminedisaster.Inthisstudy,themechanicaldeformationcharacteristicsofprimarycoal-rockcombination,artificialcoal-rockcombination,single coalandsinglerockwereanalyzedandobtainedunderuniaxialloadingconditions.Meanwhile,thedamageandfailurelawsofprimarycoal-rockcombinationwerepreliminarilyexploredbycollectingtheacousticemission(AE)behaviorinformationofsamplesduringloadingprocess.Throughcomparativeanalysis,itisfoundthat:①Theinterfacedifferenceofcoal-rockcombinationhasgreatinfluenceonthe mechanicalandAEcharacteristicsofcoal-rockcombination;②Theorderofuniaxialpeakstrengthof foursamplesis:rock>artificialcoal-rockcombination>primarycoal-rockcombination>coal;③The loadingdeformationandpeakstrengthofthecombinationbodyareinfluencedbymanyfactors,suchas interfaceconditions,elasticmodulusdifferenceofdifferentmediaandsizeeffectofmedia;④Underthe influenceofprimaryinterface,thefracturedevelopmentandpenetrationintheprimarycoal-rockcombinationisrelativelyactiveduringtheloadingyieldfailurestage,andtheearlydamagemainlyoccursin theprimarycoal-rockcombinationorthecoalandrockneartheinterfaceofcombination.

The comparative study on calculation of coal pore characteristics of different pore shapes based SAXS

NieBaisheng, WangKedi, FanYu, ZhangLetong, LunJiayun, ZhangJiabin

2020, 5(3): 284-290.

Abstract(758) PDF(113)

Abstract:
InordertoascertainthemostsuitableshapeintestingporestructureofcoalwithSmallAngle X-rayScattering(SAXS),thecoalsamplesfromDashucuncoalminelocatedin Handan,Heibei provincewere tested with SAXS and low temperature nitrogen adsorption, and the conclusion are reachedbycomparingtheporesizedistribution,specificsurfaceandporosityof7differentporeshapes andratioofheighttodiameterwiththesenitrogenadsorption. ①Thediskwiththeratioofheighttodiameterequalto0.1isthemostsuitableshapeforthecoalsamplesfromDashucuncoalmineintesting porestructure. ②ThereasonwhylargerspecificsurfaceandporosityareobtainedinSAXStestthan thesefromlowtemperaturenitrogenadsorptionisthatthecloseholeandthetaperholewithsmaller openingcanbetestedwithSAXS. Itisofmuchreferencesignificanceforthetestingofporestructure inthefuturewiththeshapeascertainedinthistest.

Research on gas migration law and gas drainage parameters optimization in goaf of fully mechanized caving face in Buertai Coal Mine

ZhouAitao, ZhangMeng, WangKai, TaoBo

2020, 5(3): 291-301.

Abstract(535) PDF(62)

Abstract:
Gasemissionfromthegoafisoneoftheimportantsourcesofgasintheworkingfaceanda reasonable goaf drainage scheme can effectively solve the problem of gas overrun in working face.Combinedwithnumericalsimulationandfieldapplication,thegasintubationextractionsystemin thegobofthefullymechanizedcavingfacein42-topcoalseamofBuertaiCoalMineisoptimizedin thispaper.Firstly,theFLUENTfluidsimulationsoftwareisutilizedtosimulatethecharacteristicsofgas migrationinthestope,consideringthedesorptionoftheremainingcoalinthegoafandthegasemission fromtheupperadjacentlayer.Thedistributionlawsofgasconcentrationinthegoafarerevealed,and theinfluenceofthedistancebetweentheextractionoutletandtheair-returncorner,drainagenegative pressureandairsupplyratioontheextractioneffectareanalyzed,theoptimizedschemeofextractionis proposedaccordingly.Thentheoptimizationschemeisappliedonthespot,focusingonthedistancebetweentheextractionoutletandtheair-returncornerandnegativepressure.Itisconcludedthatwhenthe intubationdistanceis70mandnegativepressureis12~18kPa,theextractioneffectisbetter.Theresearchresultshavetheoreticalandpracticalsignificancefortheoptimizationofgasdrainageschemein goafofhighyield,highefficiencyandlowgasmines.

Experimental study and numerical simulation on combustion characteristics of outdoor oil pool fire

LiuWei, LiYue

2020, 5(3): 302-310.

Abstract(571) PDF(79)

Abstract:
Inthispaper,low-sulfurcrudeoil,high-sulfurcrudeoilandheavynaphthaoilwereselected tocarryoutfreecombustionexperimentwithdifferentcombustionareasinoutdooropenspace,andthe experimentaldataofcombustionrate,flametemperatureandheatradiationfluxatmeasuringpoints wereobtained.Inaddition,FDSwasusedtoestablishafull-sizemodeltoobtainthesimulationresults offlametemperatureandheatradiationfluxatmeasuringpoints.Theresultsshowthat:(1)Bothlowsulfurcrudeoilandhigh-sulfurcrudeoilhavethreecombustionstages.Thecombustionrateincreases almostinalineartrendintheinitialdevelopmentstageofcombustion.Thestablecombustionstageis notobvious,andtherearenotmanyobviousstablecombustionstages.Heavynaphthashowsboiling combustionphase.(2)Thetemperatureatthecenteroftheoilpanfirstincreasesandthendecreases withtheincreaseoftheheight,whilethetemperatureoutsidetheplumedecreaseswiththeincreaseof theheight,andthisdownwardtrendisfirstsharpandthenslow.Inthecontinuousflamearea,thehigh temperatureconcentrationtendstobestable,andintheintermittentflameareaandbuoyancyplume area,thetemperaturedispersiondegreeislarger.(3)Bycustomizingthecombustionratecurveinto FDS,accurate simulation of heat radiation flux received at the measuring point can be achieved.Whentheflameradiationfluxinthecylindricalmodelisdividedintotheluminousregion atthebottomandtheplumeatthetop,thehigherthepowerofthefiresource,thecloserthecalculatedvalueistothemeasuredvalue.Forthehigh-poweroilpoolfire,thecriticalcurveof“safety distance-time” canbedeterminedtoobtainthetimethatpeoplecanbeexposedatdifferentlocationsfromthefiresource.

Research on emergency modeling of unsafe behavior of coal miners

TongRuipeng, ZhaoHui, ZhangNa, WangWei, AnYu

2020, 5(3): 311-319.

Abstract(538) PDF(135)

Abstract:
Inordertoexploretheinteractionrelationsoffactorsofminers*unsafebehaviors;emergent propertytheoryisemployedtoextracttheindividual,managing,organizationalandenvironmentalfactors thatinfluenceminers’ unsafebehaviorsbasedon144 seriouscoalminesafetyaccidentreportsfrom 2009to2018.TheDEMATEL/ISMmethodsareusedtoscreenoutkeyfactors.Onthisbasis,aminers’ unsafebehaviorsemergencymodelbasedonCGPwasestablished.Then,usingNetlogosimulationplatform,theimpactofthesefactorsontheemergencedegreeandtrendoftheunsafebehaviorofcoalminersweredynamicallysimulated,andthesimulationresultsunderstandardmodeandanalysismodewere comparedandanalyzed.Theresultsshowthattheunsafebehaviorsofcoalminersisaemergentphenomenonundertheinfluenceofmanyfactors.Theemergenceofunsafebehaviorsofcoalminersareaffectedbytheirpersonaleducationallevel,thesafetyvaluesofmanagers,theleveloforganizationalsafety commitmentandsafetystatusofworkplace.Incoalminesafetymanagement,targetedmeasuresbasedon thesefindingscanbetakentopre-controlandmanageunsafebehaviorsofminers.

Research on countermeasures of mining engineering talent training in the new situation

Yang Dapeng

2020, 5(3): 320-324.

Abstract(474) PDF(123)

Abstract:
WithChinesecomprehensiveentryintotheneweraofsocialismwithChinesecharacteristics stageofdevelopment,itisnecessarytochangetheenergyconsumptionstructuretostrengthenecologicalcivilizationandsocialandeconomicdevelopment.AsthemajorenergyinChina,coalisfacedwith theurgentneedofintelligentminingandcleanandefficientutilization.Atthesametime,theproportionof new energy demand is also gradually increasing.Facing the new situation,the training of miningengineeringprofessionalsisfacedwithnewopportunitiesandchallenges.TakingChinaUniversityofMining&Technology-Beijingasanexample,throughinvestigation,interview,practiceandother methods,thisresearchexploresanewmodeoftalenttrainingforminingengineeringprofessionalsfrom multipledimensions,suchasdisciplineconstruction,talenttrainingquality,andnewprofessionalorientation.Itishopedthattheresearchresultswillprovidetheoreticalbasisforfuturetalenttraining program.

Study on classification and support of surrounding rock of mining roadway in extremely close coal seams

LiXiaobin, HeFulian, QinBinbin, LüKai, HeWenrui

2020, 5(3): 325-333.

Abstract(552) PDF(105)

Abstract:
Inordertoexplorethestabilitycategoryandsupportmodeofsurroundingrockof mining roadwayinextremelyclosecoalseams,thestabilitycategoryofsurroundingrockisdeterminedbycomprehensiveevaluationwithmathematicalmethod.Firstly,themathematicalmodelisestablishedbyusing themethodoffuzzycomprehensiveevaluation,andfactorssuchasthenatureofsurroundingrockand stress environment are selected as the classification index of surrounding rock.Then, fuzzy comprehensive discriminant matrix,index weight and membership degree of surrounding rock are solved.Then,theclassificationofsurroundingrockstabilityisverifiedbythemethodofgreycorrelation degreeanalysis.Finally,thecorrespondingroadwaysupportmodeisputforward.Theresultsshowthat degreesofmembershipofminingroadwayinextremelyclosecoalseamstoⅠ-Ⅴtypesurrounding rocksare0.1846,0.2117,0.1866,0.1776and0.2394,respectively.Thedegreeofmembershipof Vtypesurroundingrockisthelargest,whichisconsistentwiththeverificationresults.Surroundingrock belongstoVtypeextremelyunstablesurroundingrock.Inaddition,theroofisbrokenandroadwaypressureissmallduetoextremelyclosemining.ThenU-shapedsteelbeamshedsupportisproposed.The observationofrockpressureshowsthattheeffectofroadwaysupportisremarkable.

A comparison of coal flow and carbon emissions in Shanxi province between 2011 and 2016

WeiShijie, FanJingli, YangKangdi, HouYunbing

2020, 5(3): 334-341.

Abstract(524) PDF(90)

Abstract:
InordertoexplorethechangesincoalflowandcarbonemissionsinShanxi,amajorcoal-producingprovinceduringitstransformationandupgradingofthecoalindustry,basedoncoalbalancetablesofShanxiprovince,thecoalandcarbonflowchartsof2011and2016aredrawnandcompared.The resultsshow:Thecoalde-stockingandthetransferofhigh-value-addedcoalproductsinShanxiprovince haveachievedremarkableresults;technologyofcoal-to-liquids/gashasmadebreakthroughs,and the coalindustrychainhasbeenrefined;solidwasteandwasteheatinthecoalprocessingandconversion processhavebeenresourceutilized,andtheheatingefficiencyhasfurtherincreased,from75.6% in 2011to80.2% in2016;theincreaseofthetotalamountofcoal-related carbon emission in Shanxi Provincefrom2011to2016issmall,andcarbonemissioninthepowergenerationsectorhasbeeneffec tivelycontrolledbutthatofheatingsectorhasrisenmarkedly;althoughcarbonemissionfromdomestic consumptionhasdeclinedsignificantly,ruralcarbonemissionistwicethatofurbanareas,andtherural areasarethekeyareasforcarbonemissioncontrolinthefuture.Theresearchresultsprovideadirection forfuturecoalproductionstructureadjustment,coalprocessingtechnologyimprovementandcoal-related carbonemissionmitigationinShanxiprovince,andhavereferencesignificanceforothercoal-dominated provincesfacingtheenergytransformation.

Effects of deformation rate and hydrated condition on the mechanical property of sandstone

TengTeng, DuYubing, ChenPengfei, ZhanPengfei

2020, 5(3): 342-352.

Abstract(629) PDF(52)

Abstract:
Accordingtoasetofuniaxialcompressionexperimentsofsandstone,effectsofdeformation rateandhydratedconditiononthecompressivestrength,elasticmodulus,post-peakstrainandacoustic emission(AE)characteristicswereexplored.Aone-dimensionalconstitutivemodelbyconsideringthe effectsofdeformationrateandhydratedconditionforsandstoneisestablishedandverifiedbydefinings seriesofstrengtheningandweakeningfactors.Theresultsshowthat:①Stress-straincurveofdryrock includeselasticstage,weakplasticstageandbrokenstagewhilethecompactionstage,shorterelastic stageandlongerplasticstageappearforwater-saturatedsandstone.②Deformationrateenlargesthe compressivestrengthofsandstone.Thedeformation-ratefactorofstrengthincreaseswiththeincreasing deformation rate.Water has weakening effect on the compressive strength of sandstone,and the differenceofcompressivestrengthbetweenthedryandsaturatedsandstonedecreasesgraduallywiththe increasingdeformationrate.③Theelasticmodulusofdryandsaturatedsandstoneincreaseslinearly withthedeformationrate.Waterhasweakeningeffectontheelasticmodulus.Theelasticmodulusof saturatedsandstoneislowerthanthatofdrysandstone,andtheweakeningfactorundergoeslittlechange atdifferentdeformationrates.④Deformationratehaslittleeffectonthepost-peakstrainofsandstone, thepost-peakstrainofsaturatedsandstoneismuchhigherthanthatofdrysandstone,andthehydraulic strengtheningfactorofpost-peakstrainisnotsensitivetothedeformationrate.⑤CumulatedAEenergy increaseswithdeformationrate,cumulatedAEenergyadvancesfordryspecimenandpostponesforwater-saturatedstone.Accumulationofenergyforwater-saturatedspecimenis3-5timesthatofdryspecimens.

2020 Vol. 5, No. 3