简介：Nikuradseroughness(ks)isveryimportantinthesedimenttransportpredictionbecauseitisrelatedtotheevaluationsofthevelocitydistribution,shearstressanderosiondepth.DimensionlessNikuradseroughness(ks/D,whereDisthesedimentdiameter)isusuallygiven1–2.5ontheimmobileplanbedoratlowshearstress.ButitbehavesdifferentlyonthemobileplanbedathighshearstresswithmuchsedimentpickeduptomovementwhentheShieldsparameter(Θ)islargerthan0.8–1.0.TheeffectiveNikuradseroughnessonthemobileplanbedwasderivedindirectlyfromtheerosiondepthcorrelatedtothemobileplanbedthicknessconsideringthemassconservationinthepresentstudy.TheproposederosiondepthconfirmedtherelationtotheShieldsparameterswithanextrafactorconsistingofsuspendedsedimentanditsdampingtoturbulence.Thedecrementoftheerosiondepthcausedbytheincrementofthesedimentdiameteratlargeshearstresswasobtained,whichwasusuallyabsentinclassicalempiricalformulasbasedonthebedloadtheory.GoodagreementwithexperimentswasachievedbythepresentpredictionoftheNikuradseroughness,erosiondepthandsedimenttransportrate.Discussionwasmainlyfocusedonthepredictionimprovementcausedbyconsideringtheimpactofsuspendedsedimentanditsdampingtoturbulence.

简介：Theresultsofastudyonthekeytechnologyofusingshellsand,akindofseasand,asbackfillforseareclamationaredescribedbriefly.Laboratorytestsshowthatthephysicalandmechanicalpropertiesofshellsandareasgoodasnormalquartzsand.Basedonthechemicaltestanddurabilitytestofshellsanditcouldbeconcludedthattheinfluenceofcorrosionofshellsandbyacidrainandseawatermightbeignoredintheevaluationofthesafetyanddurabilityoftheengineeringproject.Theresultsoffieldimprovementtestsshowthatthebearingcapacityofshellsandbackfillfoundationismorethan200kPaaftervibroflotationimprovementordynamiccompactionimprovement.Theshellsandisagoodbackfillmaterialforseareclamation.

简介：-Thispapercarriesouttheanalysisofmechanicsofagripsystemofthree-key-boardhydraulictongsdevelopedforoffshoreoilpipelineswhichhasbeensuccessfullyusedinoilfieldsinChina.Themainimprovementofthissystemisthataleverframestructureisusedinthestructuraldesign,whichreducesgreatlythestressesofthemajorcomponentsoftheoilpipetongs.Theoreticalanalysisandnumericalcalcu-lationbasedonthirteenbasicequationsdevelopedshowthattheteethboardofthetongsisnoteasytoslipasfrequentlyhappenstoothersystemsandisofhigherreliability.