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1、冻结细砂桩周土冰膜流变特性试验研究AbstractTheproblemofpile-soilinterfaceiscrucialtothestudyofthebearingcapacityofpilefoundation,andtheinterfacepropertiesaffectthesafetyandlong-termstabilityofpilefoundation.Thenaturalpermafrostfoundationwillbedisturbedinvariableextentbythevariouscons
2、tructionmethodswhenthepilefoundationisconstructed.Underthemutualeffectsofthevariousfactors,suchasthetemperaturedecreasesinfoundation,theatmospherictemperatureandsoiltemperaturefromthefrozensoilaroundthepile,thesurroundingsoilofthepileandthepilebodyrefreezetogetherwi
3、ththeicemembranewhichisformedfromtheunfrozenwateronthepilesurface.Thelong-termbearingcapacityofpilefoundationisaffectedbythespecialcreeppropertiesoffrozensoilandicemembrane,andtheproblemrelatedtothefoundationsurfaceisanemphasisintheresearchonpilefoundation.Thecurren
4、tdomesticandforeignresearchresultsaremainlyfocusedonthecreeppropertiesoffrozensoil,butthestudyofthecreeppropertiesinthefrozensoil-structureinterfaceisrare.Therefore,thequickdirectsheartestandcreeptestarecarriedouttostudythepropertiesoffreezesandsoil-structureinterfa
5、ce.AlltherelatedtestsinthisdissertationareconductedinthelowtemperaturelaboratoryofLanZhouJiaoTongUniversity.Themainequipmentsusedintheexperimentincludeslarge-scalelowtemperaturechamber,calorstat,modifiedstraincontrolleddirectshearapparatus,modifiedstresscontrolleddi
6、rectshearapparatus,temperaturedetector,temperaturesensorandotherapparatus.Inordertocomparethecreeppropertyintheindoortemperaturewithlowtemperature,thetesttemperatureis18℃、-1℃、-2℃.Thethicknessoficemembraneis0.5mm,1mmand2mm.Thenormalstressis50kPa,100kPa,200kPaand400kP
7、a.Thesoilisfinesand,anditsmoisturecontentis15%.ThestructurematerialisC40concrete.Byquickdirectsheartestandcreeptest,thestress-straincurve,theMohr-Coulombshearstrengthenvelopeandthegeneralizedcohesioninnegativetemperatureofthesandysoilandconcretecontactsurfaceareobta
8、ined.Thefailuretypesofsandysoil-concreteinterfaceatindoortemperatureandfrozentemperatureisanalyzed.Further,thecreepstrengthisdeterminedbyg