矿业科学学报

Research on microseismic signal denoising based on variational mode decomposition and wavelet energy entropy

SunYuan1, YangFeng1, ZhengJing2, ZhangHao1, XuMaoxuan1

2019, 4(6): 469-479.

Abstract(515) PDF(196)

Abstract:
Microseismicmonitoringtechnologyiswidelyusedinsuchfieldsasminingengineering,petroleumandgasexploitation,andsafetymonitoring.Inordertosolvetheproblemofrandomnoiseinmicroseismicsignalscollectedbymicroseismicmonitoring,adenoisingalgorithmbasedonvariationalmode decomposition(VMD)combinedwithwaveletenergyentropy(WEE) andimprovedthresholdfunction isproposed.Wavelettransformationisperformedoneachintrinsicmodefunction(IMF)componentafter VMDdecompositionoftheoriginalmicroseismicsignals.Thenoisestateofeachscalesignalischaracterizedbywaveletenergyentropy.Thethresholdofeachscalelayeriscalculatedbywaveletcoefficients ofthemaximumsubintervalofwaveletenergyentropyandthenthemicroseismicsignalsarereconstructedbythenewIMFsdenoisedthroughtheimprovedthresholdfunction.Theresultsfromnumericalsimulationsignalandrealsignalshowthattheproposedalgorithmissuperiortoempiricalmodedecomposi
tion(EMD),ensembleEMD(EEMD)andVMDcombinedwithwaveletenergyentropyhardthreshold functionandsoftthresholdfunction.Thesignal-to-noiseratioofmicroseismicsignalsareimproved.

Micro-seismic event location based on Newton iteration method and grid-search method

JiangTianqi, PeiShuojin

2019, 4(6): 480-488.

Abstract(782) PDF(203)

Abstract:
Inordertomaketheoptimizationalgorithmconvergentgloballyandquicklywhenlocatingmicro-seismicevents,consideringthegoodperformanceofgrid-searchingmethodonglobalconvergence andadvantagesofNewtoniterationmethodforcalculationspeedandaccuracy,alocationmethodbased ongrid-searchingmethodandNewtoniterationmethodisproposed.Firstanapproximatelocationresult isobtainedbygrid-seachingmethodwithsparsediscretizedgridsinthemonitoringareaandtheresultis theinitialiterationvalueforNewtoniterationmethod;secondNewtonmethodisappliedfortheaccurate locationresult.The influences of anisotropy of the velocity model and velocity measure error are analyzedinsimulationexperimentsandtheproposedmethodiscomparedwithNewtoniterationmethod, grid-searchingmethodandsimulatedannealingmethodaboutlocationaccuracy,efficiencyandstability.Thelocationresultsshowthattheproposedmethodcanlocatemicroseismiceventsaccurately,efficientlyandstably.Theproposedmethodisalsotestedwithfielddata. Thelocationresultislessthan4 m. Sothemethodispracticalformicroseismiceventlocations.

Using the discontinuous deformation analysis method to analyze the flexural toppling failure of the rock slope and the reinforcement

GongWenjun, TaoZhigang, HeManchao

2019, 4(6): 489-497.

Abstract(534) PDF(74)

Abstract:
Flexuraltopplingfailureisacomplexprocessoflandslidedisaster,onwhichtheresearches graduallybecomethekeyanddifficultpointsintheacademicfield.Takinganopen-pitmineslopefailureduetoflexuraltopplingasanexample,thisstudyattemptstointroducediscontinuousdeformationanalysismethod(DDA) tosimulatethecomplexfailureprocess.Firstly,thewaytointroduceartificial jointsintoDDAmodeltosimulatefracturingthroughtheintactrockmassesduringtheflexuraltoppling processisanalyzed.Bycomparingwiththefailurephenomenaoffieldcase,theproperwaytointroduce artificialjointsisobtained,andtheresultsconfirmDDAisapropermethodtoanalyzeflexuraltoppling failureofnumericalmethod.Thesimulationprocessshowsthatthelowerpartslopefailsfirstlybecause itisunabletosupporttheupperrocklayers,andthentheupperpartslopefailsduetothelossofthe supportfromthelowerpartslope.Theresearchonthereinforcementschemeagainstflexuraltoppling deformationoftheslopeindicatesthatifthereinforcementsdependonthestrengthoftheordinaryanchorcable,localfailureoftheanchorcablesbecomesveryeasy,whichcouldinducethefailureofthe
wholeanchorcablesfinally.

XuPeng1, ChenCheng1, GuoYang2, ZhuRuoyu1, ZhaoZhiwei1, LuoSenlin1

2019, 4(6): 498-505.

Abstract(367) PDF(94)

Abstract:
Thejointshavesignificanteffectsoncrackpropagationinslitchargeblasting. Inthispaper, thecausticmethodisadoptedtostudythelawofcrackpropagationinverticaljointedmediaunderslit chargeblasting. Theresultsshowthatcomparedwiththeintactmediawithoutjoint,insingleslitcharge blastingthevelocityofinduceddynamiccrackislowerinthemediawithverticaljoint,andthecrack lengthononesideoftheboreholedecreasesbyabout15.5%. Thereflectedwave,generatedbythereflectionofstresswaveattheverticaljoint,increasesthestressintensityfactorKdⅡ,whereasdecreasesthe Kd Ⅰoftheoppositepropagatedcrack,whichleadstosuppressingtheforwardpropagationofdynamic crack. Thecloserthedistancebetweentheholeandthejoint,thestrongerthesuppressingeffectofthe
jointoncrackpropagation. Underdoubleslitchargeblastingwithsimultaneousinitiation,theexplosion stresswave,generatedbytheadjacentborehole,hasapositiveeffectonthecrackpropagationwithoppositedirections,whichmakesboththedynamicstressintensityfactorandcrackvelocityincreasesignificantly,leadsthedynamicpassingthroughtheverticaljointsdirectlywithoutdeflection,improesthe directionalpropagationabilityofdynamiccrackinjointedrock,and the length of crack increasesby morethan50% comparedwiththesingleslitchargeblasting. Theresultsprovideatheoreticalbasisfor carryingoutdirectionalfractureblastingwithslitchargeinjointedrockmass.

JiaHaipeng1, LiuDianshu1, ChenBin2, HouShijun1, DengLimei1, YangRui1, TianShuaikang1

2019, 4(6): 506-514.

Abstract(471) PDF(142)

Abstract:
Whenthetwo-lanetunnelinthemountainousareaisexcavatedbythedrillingandblasting method,theconstructionofthereartunnelwillinevitablyproduceunfavorablevibrationeffects,thusaffectingthesafetyandstabilityoftheprecedingtunnel.Therefore,thevibrationtestandanalysisofadjacenttunnelblastingisofgreatsignificanceforthesafeconstructionofdouble-linetunnels.Inthispaper,basedon the two-line tunnel project of the Xingyan Expressway,the following conclusions ard drawnbyconductingon-sitevibrationtestsonitstunnelaxis:①Therelationshipbetweenthethreedirectionsofvibrationintensityintheadjacenttunneltestareais:verticaldirection>horizontalradial> horizontalaxis,andthesizerelationshipisrelativelyfixed.Astheblastingdistanceincreases,thedifferenceinvibrationintensitybetweenthethreedirectionsgraduallydecreases.②Theclampingofcutting holeisthebiggestandtheblastingvibrationintensityisthebiggest.③Theblastingvibrationwaveforms
ofdifferenttypesofblastholeshaveaphenomenonofrapidlyincreasingfromtheinitialvaluetothe peakvalueofthevibrationvelocity,andtheattenuationprocessisrelativelyslow,andthisphenomenon isparticularlynoticeableintheblastingofthecuthole.④Inthedouble-linetunnelblastingconstruction,reducingthemaximumsingle-stagedoseofthecuthole,increasingthedetonatorsection,decomposingthetunnelexcavationsection,andcontrollingtheblastingscaleareeffectivewaystoreducethe blastingvibration.

Research on the“two-zone” heights of soft stratum working face with slicing full-mechanized caving mining

ZhangBin1, 2, 3, XuYanchun1

2019, 4(6): 515-523.

Abstract(453) PDF(75)

Abstract:
Waterandsandinrushisoneoftheprincipalfactorsthatrestrictsafeandeffectiveproduction ofminingunderwaterbody.Thethreattosoftstratamineswithextremelythickcoalseamisespecially moreserious.Cavingzoneandfissurezone(jointname“two-zone”)heightsarethebasicparametersof waterinrush prediction.This paper observes the “two-zone” heights of extra-thick coal seam with slicingfull-mechanized caving mining in soft stratum with comprehensive measures of flushing fluid leakage,colorboreholeTVandcore-drilling,andresearchesthefracturefieldcharacteristicsofoverburdenfailurethroughdiscreteelementnumericalmethod.Theresearchresultsareasfollows:underthe
conditionofextra-thickcoalseamwithslicingfull-mechanizedcavingmininginsoftstratum,thestratum movementangleoftopslicingworkingfaceisabout75°,theratiois5.60~5.62betweencavingzoneand miningheight,theratiois11.67~12.20betweenfissurezoneandminingheight;theratiois 4.59~4.71 betweencavingzoneandminingheight,theratiois8.04~8.58betweenfissurezoneandminingheight inthebottomslicingworkingface;theheightofcavingzoneincreasesby49.41% ~50.85% andthe heightoffissurezoneincreasesby21.72% ~25.38%,butthe　 ratiobetweencavingzoneandmining heightdecreasesby16.19% ~18.33%,theratiobetweenfissurezoneandminingheightdecreasesby 29.67% ~34.10% whentheminingheightofthebottomworkingfaceis78.28% ~84.71% ofthetop workingface.Theresearchresultscanprovidereferenceforwaterdamagepredictionandtheheightof safetycoalandrockpillarinslicingfull-mechanizedcavingminingfaceunderlooseaquifer.

Microscopic experiment of consolidating tailings by Linglong cementitious material

WangBingwen1, GaoLijing1, ZhaoWenhua1, LiYanan2, 3, DingWei1

2019, 4(6): 524-530.

Abstract(462) PDF(69)

Abstract:
InordertoinvestigatetheinfluenceofLinglongcementitiousmaterialontheconsolidationof tailingsunderdifferentconditions,aseriesofbackfillblocksatdifferentratios,differentdensitiesand differentcuringagesaredesignedwithordinaryPortlandcementcontrolandtheiruniaxialcompressive strengthismeasuredthroughstrengthtest.Thenthephasecompositionandthemicro-morphologyofthe tailingsbackfillarediscussedbysuchmeasuringandtestingtechniquesasXRDandSEM.Theresults showthatthehydrationreactionofthecementitiousmaterialproducesettringiteandC—S—Hgel,and promotestheconsolidationofthetailingsbackfill;theageandtheratioofcementitiousmaterialtotailingswillaffectthedevelopmentofthecontentandmorphologyofettringiteandC—S—Hgelinthehydrationproducts,andthecontentofhydrationproductswillincreasewiththeincreaseofageandthera
tioofcementitiousmaterialtotailings.Thecontent of the productsincreasesand overlapsto form a densenetworkstructure,whichismacroscopicallyexpressedasanincreaseinstrength;themassconcentrationaffectstheporesinthetestblock,therebyaffectingthestrength.

Research on triple line-voltage cascaded converter for the medium and high voltage rectifier

ZouJia, WangCong

2019, 4(6): 531-538.

Abstract(596) PDF(128)

Abstract:
Inthispaper,anovelthree-phaserectifierbased on triple line-voltage cascaded VIENNA converter(LVC-VC) has been proposed,which could be the high power factor rectifier under high powervoltage.Comparedtoconventionalthree-phasecascadedH-bridgeconverters,intheproposednew multilevelconverters,andfewerswitchesanddccapacitorsarerequiredundersimilaroperatingconditions.Basedonthestudytotheoperationprincipleofthenewconverter,thepowerfactorcorrectionof theproposedconverterisrealizedbyemployingtraditionalone-cyclecontrolstrategy,thecarrierphaseshiftingmodulationisdesignedtoreducetheacvoltageharmonic.Thedcsidecapacitorvoltagesteady statemathematicalmodelisdeduced,thescopeofthedcsidecapacitorvoltageiscalculated,thecontrollersofdc-linkvoltagesofthethreeViennarectifiermodulesaredesigned.Simulationandexperimentalresultsverifiedtheavailabilityofthenewproposedmultilevelconverterandthevalidityofthecorrespondingcontrolstrategyapplied.

Study on variation characteristics of PM2.5 mass concentrations in Beijing after the action on comprehensive control of air pollution

ChangLingli1, ShaoLongyi1, YangShushen2, LiJie1, ZhangMengyuan1, FengXiaolei1, LiYaowei

2019, 4(6): 539-546.

Abstract(523) PDF(79)

Abstract:
BasedonthedataofthePM2.5massconcentrationsfromthemonitoringpointattheUSembassyinBeijingfrom2013to2017,thecharacteristicsofPM2.5 massconcentrationanditscorrelation withthe mass concentrations of NO2 and SO2 in Beijing in the past five years are analyzed.The emphasisisfocusedonthevariationcharacteristicsofPM2.5aftertheactiononcomprehensivecontrolof airpollutionimplementedintheautumnandwinterof2017,whichisaimedattheemissionreduction frombanningofuncontrolledcoalcombustion.TheresultsshowthattheannualaverageofPM2.5 mass
concentrationin Beijing has decreased yearly since 2013,and the decreasing range of the annual averagein2017hasreached50%.AnalysisofdataindifferentseasonsshowsthatthePM2.5massconcentrationinwinteristhehighest,followedbyautumn,spring,summerindescendingorderin2013to 2016.However,aftertheactiononcomprehensivecontrolofairpollution,itisnoticedthatthemass concentrationofPM2.5inwinter2017waslowerthanthatinautumnandspring,approachingthelevel ofsummer.Inaddition,comparedwiththepastyears,themassconcentrationsofNO2andSO2intheair alsodecreasedsignificantlyinwinter2017,inwhichthedecreaseofSO2massconcentrationismoreobvious.Theseresultsshowthattheemissionfromburningcoalshasbeeneffectivelycontrolledafterthe actiononcomprehensivecontrolofairpollution.Finally,thecorrelationanalysisshowsthatthemass concentrationsofPM2.5hasasignificantpositivecorrelationwiththoseofSO2,indicatingthatcountermeasuresforthebanningofuncontrolledcoalcombustionsuchas“coalsreplacedbygas”and“coals replacedbyelectricity”haveanobviouseffectonreducingthePM2.5emission.

Analysis of models and factors of long flame coal flotation process by response surface methodology

HaoChengliang, GuoJinyu, ChuMo, YangYanbo, WangLingshuang, GongYongqiang, ZhaoXingping

2019, 4(6): 547-557.

Abstract(496) PDF(87)

Abstract:
Inthisstudy,thephysicochemicalcleaningofShendonglongflamecoalwasinvestigatedby flocculationflotationtoproduceultracleancoal.FlotationexperimentsweredesignedwithBoxBehnken Designwhichisaresponsesurfacemethod.Theseparateactionandinteractioneffectsofkerosenedosage(A),secondaryoctanoldosage(B),andagitationspeed(C)onashcontentandyieldoftheconcentratewereevaluatedintheflotationexperiments.Theresultsshowedthatthesignificanceofinfluencing factorsonashcontentfollowedtheorder:C>B>A,AB>AC>BC,thesignificanceofinfluencingfactorson yieldfollowed the order:B>A>C,AC>BC>AB.The optimal conditions were kerosene dosage of 1.55mL,secondaryoctanoldosageof335μLandagitationspeedof3690 r/minwith1.72% ash contentand45.03% yieldrespectivelyintheconcentrate.

Study on graphene oxide modified by oligomers of p-phenylenediamine for supercapacitors

ZhangQingqing, ZhangQingwu, WangWenhua, SuShaokun, LiuHongying, LiuJiaji

2019, 4(6): 558-563.

Abstract(515) PDF(139)

Abstract:
Inordertoobtainhighspecificcapacitanceoftheelectrodeusedforsupercapacitorsbasedon newcarbonmaterials,grapheneoxide(GO),fromgraphiteoxidizedbychemicals,wasmodifiedbyoligomers of p-phenylenediamine in an autoclave.The changes of molecular structure of pphenylenediamineoligomersinethanolsolutionunderdifferentheatingprocessesweretestedbyUV-vis spectroscopy.Thestructure,morphology,electricalstorageperformanceandcyclestabilityofthecompositewerecharacterizedbyX-raydiffraction,fieldemissionscanningelectronmicroscopy,andcyclic voltammetry.Theresultsimplythatoligomersof p-phenylenediaminecaneffectivelyexpandthelayer spacingofGO,andthecompositeshowsarandomstackingmanner.Oligomersof p-phenylenediamine, heatedat60℃ for48h,havethegreatesteffectonthemodificationofGO.Specificcapacitanceofthe
compositeis453F/g,andtheretentionisabove98% after600cycles.Furthermore,aprototypesupercapacitorwasfabricatedinaCR2032cellcase.Calculatedbytheactivesubstance,theenergydensityof thecellis6.8 W·h/kg,and the power density is516.3 W/kg.And the retention is90% of its originalcharging/dischargingprocessafter1000cycles.Theresultsimplythatgrapheneoxidemodified byoligomersofp-phenylenediaminewillhaveagoodpotentialapplicationinenergystorage.

Study on the process and mechanism of acid-leaching residue of laterite nickel roasting whitening and ultrasonic-assisted centrifugal purification

LüWenqiang, ZhengShuilin, SunZhiming, HanHuajie, LiuYangyu, DiYonghao

2019, 4(6): 564-572.

Abstract(511) PDF(25)

Abstract:
Asnickelextractionresidue,theacid-leachingresidueoflateritenickelhasalargestock,low whitenessandhighheavymetalcontent.Inordertorealizeitsrecyclingapplicationandhighvaluedevelopmentinrelatedfields,inthispaper,thechemicalconstituents,phase,microscopicmorphology,pore structureandgasphaseintheroastingprocessoftherawacid-leachingresidueoflateritenickel,purifiedandwhitenedsamplesandtailingswerestudied.Themechanismofpurificationandwhiteningwas analyzedbymeansofsimultaneousthermogravimetryanalyzerandinfraredspectroscopy-massspectrometer(TG-FTIR-MS),aswellasXRD,SEMandEDS.Themechanismofpurifyingandwhiteningisprecalcinationto remove organic impurities and oxidation of iron,aluminum and chromium ions.The
second-stageroastingconvertsmetaloxidesintoNH4(Al、Fe、Cr)(SO4)2throughaseriesofreactions, thenleachingdissolvedinwaterundertheactionofultrasoundandremovedbywashing.Theheazlewooditeandcadmiumgermaniumarsenideandsomequartzwhichhadnotparticipatedinreactionswere removedbycentrifugalprecipitation.Thewhitenessofacid-leachingresidueoflateritenickelwasincreasedfrom56% to84%,theironcontentdecreasedfrom0.92% to0.2%,thespecificsurfacearea israisedfrom84m2/gto96m2/g,andtherecoveryratereachesmorethan47%.

2019 Vol. 4, No. 6