简介:Cement-mixedpiles,ascountermeasureagainstliquefactionofsiltandsandground,canimprovetheshearstrengthandbearingcapacityoffoundationsoil,meaningcement-mixedpilesarecapableofresistingdisplacementwhenanearthquakehappens.However,investigationsofcement-mixedpilesbyexperimentalmethodssuchastheshakingtabletestisfewandfarbetween.Itisespeciallytruefortheseismicperformanceofcement-mixedpilesinliquefiablerailwayfoundationsinhighseismicintensityregions.Tothisend,across-sectionoftheYuxi-Mengzirailwaywasselectedastheprototypeandstudiedbytheshakingtabletestinthisstudy.Theresultsshowedthatcompositefoundationofcementmixedpileswasnotliquefiedwhentheseismicaccelerationwaslowerthan0.30g.Intheprocessofaccelerationincreasingfrom0.30gat2Hzto0.60gat3Hz,theuppermiddlesiltoutsideslopetoewaspartlyliquefied.Thefoundationsoilundertheshouldersandcenterofsubgradewasfarfromtheinitialliquefactioncriterionduringthetest.Cementmixedpilescaneffectivelyreducetheembankmentsettlementanddifferentialsettlement.Itcanbeconcludedthat,thedesignofcement-mixedpilescanensuretheseismicperformanceofthesubgrade,andsatisfytheseismicdesignrequirementsoftheYuxi-MengzirailwayinareasofVIIIdegreesseismicfortificationintensity.
简介:称为走的墙框架结构的一个新结构的系统在这研究被建议解决产出RC框架的问题的底部,它广泛地在中国发生在象Wenchuan和Yushu地震那样的以前的地震期间。平常的RC框架模型和一个走的墙框架建模的A1/5规模被使遭到一起摇桌子运动学习新结构的系统的地震行为。这份报纸在低、中等、高的紧张摇晃下面论述动态特征,地震回答和失败和二个模型的倒塌机制。测试结果和进一步的分析证明走的墙框架结构的地震表演以控制得好的变丑模式和更一致地分布式的损坏比平常的RC框架优异。走的墙能有效地压制产出机制的底部,并且为设计实践简单、节俭、实际。
简介:Naturalgashydrate(NGH)isconsideredasoneofthenewcleanenergysourcesofthe21stcenturywiththehighestpotential.TheenvironmentalissuesofNGHproductionhaveattractedthecloseattentionofscientistsinvariouscountries.FromMay10toJuly9,2017,thefirstoffshoreNGHproductiontestintheSouthChinaSea(SCS)wasconductedbytheChinaGeologicalSurvey.Inaddition,environmentalsecurityhasalsobeeneffectivelyguaranteedviaacomprehensiveenvironmentalmonitoringsystembuiltduringtheNGHproductiontest.Themonitoringsystemconsideredsea-surfaceatmospheremethaneandcarbondioxideconcentrations,dissolvedmethaneintheseawatercolumn,andtheseafloorphysicaloceanographyandmarinechemistryenvironment.Thewholeprocesswasmonitoredviamultiplemeans,inmultiplelayers,inalldomains,andinrealtime.Aftertheproductiontest,anenvironmentalinvestigationwaspromptlyconductedtoevaluatetheenvironmentalimpactoftheNGHproductiontest.Themonitoringresultsshowedthatthedissolvedmethaneconcentrationinseawaterandthenear-seabedenvironmentcharacteristicsafterthetestwereconsistentwiththebackgroundvalues,indicatingthattheNGHproductiontestdidnotcauseenvironmentalproblemssuchasmethaneleakage.
简介:NeomysisawatschensiswascollectedonthewestcoastofJiaozhouBay,Qingdaoin1992andacclimatedinthelaboratoryconditions.Theacutetoxicitymethodusing4~6dayjuvenilemysidofthisspeciesisstudied.ThespeciesiscomparedwithM.bahiaintaxonomy,geographicdistribution,morphology,aswellasthesensitivitytoAbstracttoxins.Basedontheresults,werecommendN.awatschensistobeastandardmarineorganismfortoxicitytestinChinaandthemethodtobeappliedintoxicityevaluationofdrillingfluids.Inthispaper,wereporttheresultsoftheabovestudiesandtheapplicationofthemethodintheevaluationofseveraldrillingfluidproducts.
简介:Adynamicmodeltest(CL=4)atdifferentvelocitiesoftrain,namelydifferentloadingfrequencies,iscarriedouttostudythedynamiccharacteristicsofahigh-speedrailwaytunnelinvertanditsfoundationsoils.Notonlyaretheaccelerations,dynamiccoefficients,dynamicstressesoftheinvertandfoundationsoilsemphaticallyanalyzed,theirrelationshipwiththevelocityofthetrainarediscussedindetail.Throughlaboratorytesting,theattenuationofvibrationpropagatingfromuptherailsisobtainedandthecalculationformulaofthespeedinfluencecoefficientofthetunnelinvertispreliminarilyestablished.Thedepthofthefoundationsoilsinfluencedbyvibrationisalsodeterminedinthisstudy.Itisshownthattheresponsesofthetunnelinvertandfoundationsoilstovibrationareslightlyincreasedwiththevelocityofthetrain;circumferentialstressesinthebottomoftheinvertaretensilestressesandmaximumstressesappearunderthefootoftherails;thedynamicsoilpressuresofthefoundationdecreasequicklywiththedistanceawayfromthetunnelinvertandanexponentialrelationshipexistsbetweenthem.
简介:TheLouisschemeandtheCOAREalgorithm(version3.0)aretestedagainsteddycovarianceandinertialdissipationmethodsforfrictionvelocityestimatesindifferentwind-sea/swellregimes.Atmosphericforcingdata,tabulatedbyDonelanetal.(1997.JPhysOceanog,27:2087~2099),werecollectedfromamastontheforedeckofaSWATH(smallwater-planearea,twinhull)shipindeepseaofftheStateofVirginiaduringthesurfacewavedynamicsexperiment.Thesedataarerepresentativeoflowtomoderatewindregimes.TheaerodynamicroughnesslengthisdeterminedbyusingtheCharnockrelationship.TheintercomparisonshowsthattheLouisschemeandtheCOAREalgorithmunderestimatethefrictionvelocityby6%and3%respectivelyunderpurewindseaconditions,15%and13%respectivelyundercrossswellconditions,and21%and17%respectivelyundercounterswellconditions.Theanalysisshowsthattheseunderestimationswerecausedbythemethodchosentodeterminetheaerodynamicroughnesslengthbecauseitsignificantlyunderestimatestheaerodynamicroughnesslength.Itisespeciallytrueunderthecrossswellandcounterswellconditions.
简介:InMayandJulyof2017,ChinaGeologicalSurvey(CGS),andGuangzhouMarineGeologicalSurvey(GMGS)carriedoutaproductiontestofgashydrateintheShenhuareaoftheSouthChinaSeaandacquiredabreakthroughoftwomonthscontinuousgasproductionandnearly3.1×10^5m^3ofproduction.ThegashydratereservoirintheShenhuareaofChina,ismainlycomposedoffine-grainedclaysiltwithlowpermeability,andverydifficultforexploitation,whichisverydifferentfromthosediscoveredintheUSA,andCanada(bothareconglomerate),Japan(generally,coarsesand)andIndia(fracture-filledgashydrate).Basedon3Dseismicdatapreserved-amplitudeprocessingandfineimaging,combinedwithlogging-while-drilling(LWD)andcoreanalysisdata,thispaperdiscussestheidentificationandreservoircharacterizationofgashydrateorebodiesintheShenhuproductiontestarea.Wealsodescribethedistributioncharacteristicsofthegashydratedepositsandprovidedreliabledatasupportfortheoptimizationoftheproductionwelllocation.ThroughBSRfeaturerecognition,seismicattributeanalysis,modelbasedseismicinversionandgashydratereservoircharacterization,thispaperdescribestworelativelyindependentgashydrateorebodiesintheShenhuarea,whicharedistributedinthenorth-southstripandtendtobethickerinthemiddleandthinnerattheedge.Theeffectivethicknessofoneorebodyisbiggerbutthedistributionareaisrelativelysmall.ThemodelcalculationresultsshowthatthedistributionareaofthegashydrateorebodycontrolledbyW18/W19isabout11.24km^2,withanaveragethicknessof19mandamaximumthicknessof39m,andthedistributionareaofthegashydrateorebodycontrolledbyW11/W17isabout6.42km^2,withanaveragethicknessof26mandamaximumthicknessof90m.
简介:WecompilearegionalcatalogueofearthquakeswithmomentmagnitudeoftheCenter-SouthernAsiatestarea(20°-35°N,85°-105°E)fortheGlobalSeismicHazardAssessmentProgram(GSHAP).Therearesignificantinhomogeneousanduncompleteddata,andnuniformityofearthquakemagnitudesinthistestareabecausethisregionissituatedontheboundariesofmanycountries,suchasChina,India,Nepal,Vietnam,etc.WeestablisharelationshipbetweenGutenbergsurface-wavemagnitudeandIASPEIsurface-wavemagnitude,whichcanbeusedforconversionofdifferentmagnitudescalesintomomentmagnitudeforthiscatalogue.AcatalogueofeventswithMw≥6.0ofthistestareaisgivenattheendofthispaper.
简介:Artificialearthquakecataloguesimulationisoneofthewaystoeffectivelyimprovetheincompletenessoftheexistingearthquakecatalogue,thescarcityoflargeearthquakerecordsandtheimprovementofseismologicalresearch.BasedonthePoissondistributionmodelofseismicactivityandtheGutenberg-Richtermagnitude-frequencyrelationship,theMonteCarlomethodwhichcandescribethecharacteristicsofthestochasticnatureandthephysicalexperimentprocessisused.ThispapersimulatesthefutureseismiccataloguesoftheFenhe-Weiheseismicbeltofdifferentdurationsandconductsstatisticaltestsonthem.TheanalysisshowsthatthesimulationcataloguemeetsthesetseismicactivityparametersandmeetsthePoissondistributionhypothesis,whichcanobtainabettersimulatedearthquakecataloguesthatmeetstheseismicactivitycharacteristics.Accordingtothesimulatedearthquakecatalogues,futureearthquaketrendsinthisregionareanalyzedtoprovidereferenceforseismichazardanalysis.