土力学课件第六章土压力

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1、第六章土压力河海大学岩土工程研究所ResearchInstituteofGeotechnicalEngineering,HohaiUniversityChapter6EarthPressure第一节概述Introduction土压力概念Whatisearthpressure?土压力种类：Typesofearthpressure静止土压力：EarthpressureatrestWhatisearthpressure?第一节概述IntroductionEarthpressure:Thepressureappliedonaretainin

2、gwallfromsoil第一节概述Introduction主动土压力Activeearthpressure被动土压力Passiveearthpressure静止土压力EarthpressureatrestTypesofearthpressure?第一节概述Introduction主动土压力Activeearthpressure:Thewallmovesawayfromthesupportedsoil,andthehorizontalsoilpressuresarerefereedtoasactivepressure.Thesoil

3、isinactivestate.被动土压力Passiveearthpressure:Thewalliscausedtomovetowardsthesoilbeingsupported,andthehorizontalsoilpressuresarerefereedtoaspassivepressure.Thesoilisinpassivestate.静止土压力Earthpressureatrest:Thewallisrigidanddoesnotyield,thatisthereisnomovementtakingplace,the

4、horizontalsoilpressuresaresaidtobeat-restpressure.Thesoilisinat-reststate.Typesofearthpressure?主动极限平衡状态:Activestate:plasticequilibriumwithlateralexpansiontakingplace.被动极限平衡状态:Passivestate:plasticequilibriumwithlateralcompressiontakingplace.静止平衡状态:At-reststate:elasticeq

5、uilibriumwithnolateralstraintakingplace.第一节概述IntroductionUndernaturalconditionsofdeposition,withsemi-infiniteextent,thereisanegligibleamountofhorizontalstrain,thesoilissaidtobeinanat-reststate(orK0state),andthehorizontaleffectivestressis:WhereK0=coefficientofearthpress

6、ureatrest.At-restearthpressure?Theresultantthrustisequaltotheareaofthepressuredistributiondiagram,I.e.第二节朗肯土压力理论Rankine’stheoryActiveearthpressureincohesionlesssoilsSmoothverticalback,horizontalsurfaceThewallmovesawayfromtheearthfill,Verticalstressismajorprincipalstre

7、ssSoilinstateofplasticequilibriumKaiscoefficientofactiveearthpressure第二节朗肯土压力理论Rankine’stheoryActiveearthpressureincohesionlesssoilsPressuredistributionAuniformsurchargeload(q)isappliedoverthewholesurfaceThewallmovesawayfromtheearthfill,Verticalstressismajorprincipalst

8、ress第二节朗肯土压力理论Rankine’stheoryActiveearthpressureincohesionlesssoilsTheresultantthrustisequaltotheareaofthepressuredis