简介:AnewcentrifugebasedmethodfordeterminingtheresponseofcontinuousburiedpipetoPGDispresented.ThephysicalcharacteristicsoftheRPI's100g-tongeotechnicalcentrifugeandthecurrentlifelineexperimentsplit-boxaredescribed:Thesplit-boxcontainsthemodelpipelineandsurroundingsoilandismanufacturedsuchthathalfcanbeoffset,inflight,simulatingPGD.Inaddition,governingsimilituderelationswhichallowonetodeterminethephysicalcharacteristics,(diameter,wallthicknessandmaterialmodulusofelasticity)ofthemodelpipelinearepresented.Finally,recordedstrainsinducedintwoburiedpipeswithprototypediametersof0.63mand0.95m(24and36inch)subjectto0.6and2.0meters(2and6feet)offullscalefaultoffsetsandpresentedandcomparedtocorrespondingFEresults.
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简介:Thehollow-pipeperforatedbreakwaterisoflowreflection.Inthispaperthefunctionsofreflectioncoefficientsofbothregularandrandomwavesaretheoreticallyderived,basedontheconceptoflinearsuperimpositionofreflectedandincidentwavesandwiththetotalflowratecontinuityofintegralforminsteadofthenon-continuityoftheboundarycondition,andbasedontheconceptoflinearwavespectrumtheory.Comparisonsbetweentheoreticalresultspresentedhereandmeasurementsofmodeltestsshowreasonableagreement.
简介:Thisstudyconsidersthetorsionalvibrationofapipepileinatransverselyisotropicsaturatedsoillayer.BasedonBiot’sporoelastictheoryandtheconstitutiverelationsofthetransverselyisotropicmedium,thedynamicgoverningequationsoftheouterandinnertransverselyisotropicsaturatedsoillayersarederived.TheLaplacetransformisusedtosolvethegoverningequationsoftheouterandinnersoillayers.Thedynamictorsionalresponseofthepipepileinthefrequencydomainisderivedutilizing1Delastictheoryandthecontinuousconditionsattheinterfacesbetweenthepipepileandthesoils.ThetimedomainsolutionisobtainedbyFourierinversetransform.Aparametricstudyisconductedtodemonstratetheinfluenceoftheanisotropiesoftheouterandinnersoilonthetorsionaldynamicresponseofthepipepile.
简介:Standingwavesareformedduetothereflectionwhenwavesmeetverticalwall,thereforestrongstructuresareneededtokeepthewallstabilityundertheseriouswaveattack.Fortheimprovementoftheworkingconditionandincreaseofthestabilityofthewall,thelowerreflectingbreakwatershaveat-tractedcloseattentionReportsmostlyfromJapaneseresearchersareoftenconcernedwiththewallofcaissonequippedwithopenwindows.Inthispaperakindofhollow-pipeperforatedbreakwaterisexam-inedwhichwavesmaypartiallyperforateintotheharbourbasin.Thewaveinfrontofthewallcanonlyformpartialstandingwaveandwaveforceisreducedobviously.Andthetheoreticalcalculationofwaveforceandanalysisofwaveforcespectrumareallderived.Comparisonbetweentheresultsfromtheoreticalcalculationandhydraulicmodelingshowsreasonableagreement.
简介:Itisawellknownfactthatmagnaticcryoto-explosion,asaspeeialformofmagmatismunderthenear-surfacecondition,hasacloseconncctionwithcdogcnicmctaldcposits,particularlywiththoseofporphyrytyPe,suchaSporphyryCu-Mo,Pb-Zn,W-SnandUdcposits’However,onlyinrcccntyearsbavetheChineseoregeologistsandpetrologistsgivenin
简介:-Thispapercarriesouttheanalysisofmechanicsofagripsystemofthree-key-boardhydraulictongsdevelopedforoffshoreoilpipelineswhichhasbeensuccessfullyusedinoilfieldsinChina.Themainimprovementofthissystemisthataleverframestructureisusedinthestructuraldesign,whichreducesgreatlythestressesofthemajorcomponentsoftheoilpipetongs.Theoreticalanalysisandnumericalcalcu-lationbasedonthirteenbasicequationsdevelopedshowthattheteethboardofthetongsisnoteasytoslipasfrequentlyhappenstoothersystemsandisofhigherreliability.
简介:Thepropagationofstresswavesinalarge-diameterpipepileforlowstraindynamictestingcannotbeexplainedproperlybytraditional1Dwavetheories.Anewcomputationalmodelisestablishedtoobtainawaveequationthatcandescribethedynamicresponseofalarge-diameterthin-walledpipepiletoatransientpointloadduringalowstrainintegritytest.Ananalyticalsolutioninthetimedomainisdeducedusingtheseparationofvariablesandvariationofconstantmethods.Thevalidityofthisnewsolutionisverifiedbyanexistinganalyticalsolutionunderfreeboundaryconditions.Theresultsofthistimedomainsolutionarealsocomparedwiththeresultsofafrequencydomainsolutionandfieldtestdata.Thecomparisonsindicatethatthenewsolutionagreeswellwiththeresultsofprevioussolutions.Parametricstudiesusingthenewsolutionwithreferencetoacasestudyarealsocarriedout.Theresultsshowthatthemodenumberaffectstheaccuracyofthedynamicresponse.Amodenumbergreaterthan10isrequiredtoenablethecalculateddynamicresponsestobeindependentofthemodenumber.Thedynamicresponseisalsogreatlyaffectedbysoilproperties.Thelargerthesideresistance,thesmallerthedisplacementresponseandthesmallerthereflectedvelocitywavecrest.Thedisplacementincreasesasthestresswavespropagatealongthepilewhenthepileshaftisfree.Theincidentwavesofdisplacementandvelocityresponsesofthepilearenotthesameamongdifferentpointsinthecircumferentialdirectiononthepiletop.However,thearrivaltimeandpeakvalueofthepiletipreflectedwavesarealmostthesameamongdifferentpointsonthepiletop.