简介：Theprobabilitydistributionsofsandparticles'lift-offandincidentvelocitiesinawind-blownsandfluxplayveryimportantrolesinthesimulationofthewind-blownsandmovement.Inthispaper,theverticalandthehorizontalspeedsofsandparticleslocatedat1.0mmaboveasand-bedinawind-blownsandfluxareobservedwiththeaidofPhaseDopplerAnemometry(PDA)inawindtunnel.Basedontheexperimentaldata,theprobabilitydistributionsofnotonlytheverticallift-offspeedbutalsothelift-offvelocityaswellasitshorizontalcomponentandtheincidentvelocityaswellasitsverticalandhorizontalcomponentscanbeobtainedbytheequaldistancehistogrammethod.Itisfound,accordingtotheresultsoftheχ2-testfortheseprobabilitydistributions,thattheprobabilitydensityfunctions(pdf's)ofthesandparticles'lift-offandincidentvelocitiesaswellastheirverticalcomponentsaredescribedbytheGammadensityfunctionwithdifferentpeakvaluesandshapesandthedownwindincidentandlift-offhorizontalspeeds,respectively,canbedescribedbythelognormalandtheGammadensityfunctions.Thesepdf'sdependonnotonlythesandparticlediameterbutalsothewindspeed.

简介：Inordertoinvestigatetheinfluenceoftheverticalvibrationloadingontheliquefactionofsaturatedsand,onedimensionalmodelforthesaturatedsandwithaverticalvibrationispresentedbasedonthetwophasecontinuousmediatheory.Thedevelopmentoftheliquefactionandtheliquefactionregionareanalyzed.Itisshownthattheverticalvibrationloadingcouldinduceliquefaction.Therateoftheliquefactionincreaseswiththeincreaseoftheinitiallimitstrainorinitialporosityoramplitudeandfrequencyofloading,andincreaseswiththedecreaseofthepermeabilityorinitialmodulus.Itisshownalsothatthereisaphaselaginthesandcolumn.Whenthesandpermeabilitydistributionisnon-uniform,theporepressureandthestrainwillrisesharplywherethepermeabilityisthesmallest,andfracturemightbeinduced.Withthedevelopmentofliquefaction,thestrengthofthesoilfoundationbecomessmallerandsmaller.Inthelimitingcase,landslidesordebrisflowscouldoccur.