河海大学土力学课件

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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:Thepressureap

2、pliedonaretainingwallfromsoil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,andthehorizontalsoilpressuresarere

3、fereedtoasactivepressure.Thesoilisinactivestate.被动土压力Passiveearthpressure:Thewalliscausedtomovetowardsthesoilbeingsupported,andthehorizontalsoilpressuresarerefereedtoaspassivepressure.Thesoilisinpassivestate.静止土压力Earthpressureatrest:Thewallisrigidanddoe

4、snotyield,thatisthereisnomovementtakingplace,thehorizontalsoilpressuresaresaidtobeat-restpressure.Thesoilisinat-reststate.Typesofearthpressure?主动极限平衡状态:Activestate:plasticequilibriumwithlateralexpansiontakingplace.被动极限平衡状态:Passivestate:plasticequilibriu

5、mwithlateralcompressiontakingplace.静止平衡状态:At-reststate:elasticequilibriumwithnolateralstraintakingplace.第一节概述IntroductionUndernaturalconditionsofdeposition,withsemi-infiniteextent,thereisanegligibleamountofhorizontalstrain,thesoilissaidtobeinanat-restst

6、ate(orK0state),andthehorizontaleffectivestressis:WhereK0=coefficientofearthpressureatrest.At-restearthpressure?Theresultantthrustisequaltotheareaofthepressuredistributiondiagram,I.e.第二节朗肯土压力理论Rankine’stheoryActiveearthpressureincohesionlesssoilsSmoothve

7、rticalback,horizontalsurfaceThewallmovesawayfromtheearthfill,VerticalstressismajorprincipalstressSoilinstateofplasticequilibriumKaiscoefficientofactiveearthpressure第二节朗肯土压力理论Rankine’stheoryActiveearthpressureincohesionlesssoilsPressuredistributionAunif

8、ormsurchargeload(q)isappliedoverthewholesurfaceThewallmovesawayfromtheearthfill,Verticalstressismajorprincipalstress第二节朗肯土压力理论Rankine’stheoryActiveearthpressureincohesionlesssoilsTheresultantthrustisequaltotheareaofthepressuredis