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1、AdvancedsoilmechanicsConstitutivelawofsoilMicrostructureofsoilStrengthofsoilConsolidationandrheologySlopestability1.AboutStress-strainRelationship(1)Whatisconstitutivelaw?Stress-strainrelationshipStress-strain-strengthrelationshipStress-strain-timerelationshipStress-strain-tempera
2、turerelationshipstrainstressstrength(2)Conventionalcomputationofstress-strainrelationshipofsoilsSimplestressconditionSettlementofbuilding——onedimensionalproblemConfinedcompressiontest,(oedometertest)pshepaCoefficientofcompressionlinearnonlineareepCompressionindexComplicatedstresss
3、tateEarthdam,undergroundstructure,harbor,excavation,etc.ExtensiveHooke’slaw(linearassumption)expandcompress(3)Stress-straintestsConventionaltriaxialtestFirst—cellpressureThen—deviatorstressStraincomponentspistonorganicglassbasecylindricalcellrubbermembranecapthroughwatertoapplythr
4、oughpistontoapplyPlanestraintestSampleisenclosedinarubbermembrane,andisputinthecylindricalcell.Cellpressure——Axialstress——Dike,dam,retainingwall,nodeformationinlongitudinaldirection—TruetriaxialtestApplyMeasureHollowedtorsionalsheartestMTakehalfofringasisolatebody----fromMd1d22.De
5、formationCharacteristicsofSoils(1)Non-linearandnon-elasticmetalsoilPlasticstrain—irrecoverablestrain,duetoadjustmentofpositionofgrains.Oneparticlemayslipoveranotherparticle,maydropintoporespace,andtherelativepositionbetweenthetwoparticlescannotberecovered.Deformationcannotberecove
6、red(2)Plasticvolumetricstrainmetal—noplasticvolumetricstrainsoil—obviousplasticvolumetricstraininducedbyploadingpunloadingMacroscopic—compressMicroscopic—slipbetweengrainsinducedbyShearstressPerformtriaxialtestwithp=constantincrease,butdecreasep=constantp=constantShearcompressionS
7、heardilationp—averagenormalstress,orglobalstressSheardilationDilation——densesand,overconsolidatedclayCompression——loosesand,normalconsolidatedclaySheardilativeShearcompressive(3)PlasticshearstrainExpressionofshearstrainShearstressandstrainonagivenplaneandComplicatestressstateOctah
8、edralshearstressOctahedralnormals