Lesson15soilmechanical土木工程专业英语省公共课一等奖全国赛课获奖课件.pptx

Lesson 15Text:Soil Mechanics教学要求教学要求:1、掌握相关掌握相关Soil Mechanics专业术语；专业术语；2、熟悉一些常见表示方式；熟悉一些常见表示方式；3、延伸了解一些土力学历史和名人；延伸了解一些土力学历史和名人；4、能正确、流畅地翻译能正确、流畅地翻译第1页 Soilmechanicsisconcernedwiththeuseofthelawsofmechanicsandhydraulicsinengineeringproblemsrelatedtosoil.Soilisanaturalaggregate ofmineralgrains,withorwithoutorganicconstituents,formedbythechemicalandmechanicalweatheringofrock.Itconsistsofthreephases:solidmineralmatter,water,andairorothergas.Soilsareextremelyvariablecomposition,anditwasthisheterogeneity thatlongdiscouragedscientificstudiesofthesedeposits.hydraulicshaidr:liks水力学水力学 aggregategrigeit集合体集合体phasefeiz阶段阶段,相相heterogeneity.hetrudini:iti异质性异质性,多相性多相性 土力学研究是在工程问题中与土相关力学和水力学定土力学研究是在工程问题中与土相关力学和水力学定律应用。土是矿物粒天然集合物，这些矿物粒是岩石经过律应用。土是矿物粒天然集合物，这些矿物粒是岩石经过化学或物理风化而形成，含或者不含有机成份。土包含有三个化学或物理风化而形成，含或者不含有机成份。土包含有三个相：固态矿物质，水，空气或其它气体。土组成极其复杂，相：固态矿物质，水，空气或其它气体。土组成极其复杂，正是这种异质性，长久以来妨碍了对这个堆积物研究。正是这种异质性，长久以来妨碍了对这个堆积物研究。第2页(生物体,有机体)第3页Gradually,theinvestigationoffailuresofretainingwalls,foundations,embankments,pavement,andotherstructuresresultedinabodyofknowledgeconcerningthenatureofsoilsandtheirbehaviorsufficienttogiverisetosoilmechanicsasbranchofengineeringscience.retainingwall:挡土墙挡土墙embankmentsimbkmnt堤防堤防,筑堤筑堤pavementpeivmnt路面路面 逐步地，经过对那些失败挡土墙、基础、堤坝、路面逐步地，经过对那些失败挡土墙、基础、堤坝、路面及其它结构调查研究，人们积累了大量相关土类型及及其它结构调查研究，人们积累了大量相关土类型及其性质知识，从而形成了工程学科分支其性质知识，从而形成了工程学科分支土力学。土力学。第4页History.Littleprogresswasmadeindealingwithsoilproblemsonascientificbasisuntilthelatterhalfofthe18thcentury,whentheFrenchphysicistCharles-Augustin de Coulombpublishedhistheoryofpressure(1773).In1857theScottishengineerWilliam Rankinedevelopedtheoryofequilibriumofearthmassesandappliedittosomeelementaryproblemsoffoundationengineering.Thesetwoclassicaltheoriesstillformthebasisofcurrentmethodsofestimatingearthpressure,eventhoughtheywerebasedonthemisconceptionthatallsoilslackcohesion,asdoesdrysand.Twentieth-centuryadvanceshavebeeninthedirectionoftakingcohesionintoaccount;understandingthebasicphysicalpropertiesofsoilsingeneralandofatheplasticityofclayinparticular;andsystematicallystudyingtheshearing characteristicsofsoilthatis,theirp e rf o rma n c e u n d e r c o n d it io n s o f s lid in g.第5页cohesionkuhi:n 内聚力内聚力,粘聚力粘聚力;plasticityplstisiti塑性塑性;历史。18世纪后叶之前，人们在研究有关土科学理论方面进展很小，直到法国物理学家查里.奥古斯丁.库仑（Charles-Augustin de coulomb）在1773年出版了他土压力学说。1857年，苏格兰工程师朗肯（William Rankine）发展了土平衡理论，并将其用于基础工程基本问题中。尽管这两个经典理论是建立错误假设上，即认为土和干燥沙子一样是缺乏粘聚力，但依然形成了当前估算土压力方法理论基础。这方面研究，在二十一世纪有了突破，粘聚力计入计算，了解了一般情况土物理性质和特殊情况下土塑性，还系统地研究了土剪切性质也就是土滑动时性能。第6页CharlesAugustindeCoulomb (17361806)was a French physicist.He is best known as the discoverer of Coulombslaw,which defines the force of electrostatic attraction and repulsion.The SI unit of charge,the coulomb,was so named in his honour.WilliamJohnMacquornRankine(1820-1872)was a Scottish engineer and physicist.Rankine 被后人誉为那个时代天才，他在热力学、流体力学及土力学等领域都有出色贡献。第7页BothCoulombsandRankinestheoriesassumedthatthesurfaceofrupture ofsoilsubjectedtoashearingforceisaplane.Whilethisisareasonableapproximation forsand,cohesivesoilstendtoslipalongacurvedsurface.Intheearly20thcentury,Swedishengineersproposedacirculararcasthesurfaceofslip.Duringthelasthalfcenturyconsiderableprogresshasbeenmadeinthescientificstudyofsoilandintheapplicationoftheoryandexperimentaldatatoengineeringdesign.rupture rpt(r)rpt(r)断裂断裂approximation 靠近、近似值靠近、近似值cohesive kuhi:siv kuhi:siv 粘性粘性(有结合性有结合性,有粘聚性有粘聚性)第8页AsignificantadvancewasmadebytheGermanengineerKarl Terzaghi,whoin1925publishedamathematicalinvestigationoftherateofconsolidationofclaysunderappliedpressure.Hisanalysis,whichwasconfirmedexperimentally,explainedthetimelagofsettlementsonfullywaterloggedclaydeposits.Terzaghicoinedthetermsoilmechanicsin1925whenhepublishedthebookErdbaumenchanik(“Earth-.BuildingKarlTerzaghi （1883 1883 1963 1963）卡尔）卡尔特扎吉特扎吉consolidation kn.slidein kn.slidein 固结固结waterlogged w:tlgd w:tlgd 浸满水浸满水mechanics”)第9页Karl TerzaghiTheFatherofSoilMechanics.Born:October2,1883inPragueDied:October25,1963inWinchester,MassachusettsHewasmarriedtoRuthD.Terzaghi,ageologist.HewontheNormanMedalofASCEfourtimes(1930,1943,1946,and1955).Hewasgivenninehonorarydoctoratedegreesfromuniversitiesineightdifferentcountries.Hestartedmodernsoilmechanicswithhistheoriesofconsolidation,lateral earth pressures,bearing capacity,andstability.nutshell:第10页Researchingonsubgradematerials,thenaturalfoundationunderpavements,wasbegunabout1920bytheU.S.Bureau of Public Roads.Severalsimpletestswerecorrelatedwiththepropertiesofnaturalsoilsinrelationtopavementdesign.InEngland,theRoad Research Boardwassetupin1993.In1936thefirstinternationalconferenceonsoilswasheldatsubgrade 路基路基U.S.BureauofPublicRoads美国公路局美国公路局 RoadResearchBoard 公路研究部公路研究部HarvardUniversity.第11页 Today,thecivilengineerreliesheavilyonthenumericalresultsofteststoreinforceexperienceandcorrelatenewproblemswithestablishedsolutions.Obtaining truly representative samples of soils for such tests,however,is extremely difficult;hence there is a trend toward testing on the site instead of in the laboratory,and many important properties are now evaluated in this way.今天，土木工程师都会借重于试验数据来加强经今天，土木工程师都会借重于试验数据来加强经验，把新问题和已确定处理方法联络起来。不过，要验，把新问题和已确定处理方法联络起来。不过，要取得含有代表性土样做测试，是非常困难，所以，取得含有代表性土样做测试，是非常困难，所以，现在倾向于用在现场做测试来取代试验室试验。现在，现在倾向于用在现场做测试来取代试验室试验。现在，大多数主要土特征采取这种方法来评定。大多数主要土特征采取这种方法来评定。第12页 Engineering properties of soils.Thepropertiesofsoilthatdeterminetheirsuitabilityforengineeringuseincludeinternal friction,cohesion,compressibility,elasticity,permeability,andinternalfriction 内摩擦力内摩擦力cohesion kuhi:n kuhi:n 粘聚力粘聚力compressibility km.presibiliti km.presibiliti 压缩性压缩性permeability.p:mibiliti .p:mibiliti 渗透性渗透性capillarity kpilriti kpilriti 毛毛细性性Capillarity.第13页Internalfrictionistheresistancetoslidingofferedbythesoilmass.Sandandgravelhavehigherinternalfrictionthanclays;inthelatteranincreaseinmoisturelowerstheinternfriction.Thetendencyofasoiltoslideundertheweightofastructuremaybetranslatedintoshear;thatis,amovementofamassofsoilinplans,eitherhorizontal,vertical,orother.Suchashearingmovementinvolvesadangerof 内摩擦力土体是抵抗滑动力。沙子和沙砾比粘土内内摩擦力土体是抵抗滑动力。沙子和沙砾比粘土内摩擦力大，后者内摩擦力伴随湿气增加而降低。土在结摩擦力大，后者内摩擦力伴随湿气增加而降低。土在结构重力下，其滑动趋势可能会转换成剪切，也就是土构重力下，其滑动趋势可能会转换成剪切，也就是土平面，水平、竖向或者其它方向运动。这种剪切运平面，水平、竖向或者其它方向运动。这种剪切运动会造成危险建筑事故。动会造成危险建筑事故。buildingfailure.第14页Alsoresistingthedangerofshearisthepropertyofcohesion,whichisthemutualattractionofsoilparticles duetomolecularforcesandtheexistenceofmoisturebetweenthem.Cohesionisgenerallyveryhighinclaysbutalmostnonexistentinsandsor silts.Cohesionvaluesrangefromzerofordrysandto2,000poundspersquarefootforverystiffclay.mutual mju:tjul mju:tjul共同共同,相互相互 particle p:tikl p:tikl 粒子粒子,点点,极小量极小量molecular mulekjul mulekjul 分子分子silt silt silt 淤泥淤泥第15页 Compressibilityisanimportantsoilcharacteristicbecauseofthepossibilityofcompactingthesoilbyrolling,tamping,vibration,orothermeans,thusincreasingitsdensityandload-bearingstrength.An elastic soil tends to resume its originalcondition aftercompaction.Elastic(expansible)soilareunsuitableassubgradesforflexible pavementssincetheycompactandexpandasavehiclepassesoverthem,causingfailureofthepavement.rolling r:uli r:uli碾压碾压 tampingtmpi tmpi 扎实扎实vibration vaibrein vaibrein 振动振动flexible pavements柔性路面柔性路面第16页Crosssectionsofmodernpavement 第17页 Permeabilityisthepropertyofasoilthatpermitstheflowofthewaterthroughit.Freezing-thawingcyclesinwinterandwetting-dryingcyclesinsummeralterthepacking densityofsoilgrains.Permeability Capillaritycauseswatertorisethroughthesoilabovethenormalhorizontalplaneoffreewater.Inmostsoilnumerous channelsforcapillaryactionexist;inclays,moisturemayberaisedasmuchasthawing:i :i 融化融化 packingdensity 堆积密度堆积密度numerous nju:mrs nju:mrs 许多许多canbereducedbycompaction.30feetbycapillarity.第18页Densitycanbedeterminedbyweightandvolumemeasurementsorbyspecialmeasuringdevices.Stability ofsoilsismeasuredbyaninstrumentcalledastabilometer,whichspecificallymeasuresthehorizontalpressuretransmittedbyaverticalload.Consolidationisthecompactionorpressingtogetherofsoilthatoccursunderaspecificloadcondition;thatstability stbiliti stbiliti 稳定性稳定性 stabilometer.steibilmit .steibilmit 稳定仪稳定仪,稳定性量测仪稳定性量测仪 密度能够经过测定重量和体积得到，或者用特殊测量密度能够经过测定重量和体积得到，或者用特殊测量仪器测得。土稳定性可用一个稳定仪测得，稳定仪可明确仪器测得。土稳定性可用一个稳定仪测得，稳定仪可明确测出竖向荷载带来水平压力。固结是土在一个特殊荷载下测出竖向荷载带来水平压力。固结是土在一个特殊荷载下发生压实或者挤压，一样也能够测试出来。发生压实或者挤压，一样也能够测试出来。propertyisalsotested.第19页Site Investigation.Soilsurveysareconductedtogatherdataonthenature and extentofthesoilexpectedtobeencounteredonaproject.Theamountofeffortspentonsiteinvestigationdependsonthesizeandimportanceoftheproject;itmayrange fromvisualinspectionto elaborate subsurfaceexplorationbyboringandlaboratorytesting.Collectionofrepresentativesampleisessentialforproperidentificationandclassificationofsoils.survey s:vei s:vei 测量测量 elaborate ilbrt ilbrt 精细精细,详尽详尽 boring b:ri b:ri 钻孔钻孔identification ai.dentifikein ai.dentifikein 判定判定,确认确认第20页Thenumberofsamplestakendependsonpreviouslyavailabledata,variationinsoiltypes,andthesizeoftheproject.Generally,inthenaturalprofileatalocation,thereismorevariationinsoilcharacteristicswithdepththanhorizontaldistance.Itisnotgoodpracticetocollectcompositesamplesforanygivenhorizon(layer),sincethisdoesnottrulyrepresentanyonelocationandcouldprovemisleading.Evenslightvariationinsoilcharacteristicsinahorizonshouldbedulynoted.Classificationofthesoilintermsofgrainsizeandtheliquidandplastic limitsareparticularlyprofile prufail prufail 剖面，侧面剖面，侧面plasticlimit限限importantsteps.第21页 An understanding of the eventual use of the data obtained during site investigation is important.Advanceinformationonthesiteconditionsishelpfulinplanninganysurveyprogram.Informationontopography,geologicalfeatures(outcrops,roadandstreamcuts,lakebeds,weatheredremnants,etc.),paleontological maps,aerialphotographs,welllogs,andexcavationscanproveinvaluable.Geophysicalexplorationmethodsyieldusefulcorroboratorydata.Measurementoftheelectricalresistivity ofsoilsprovidesaninsightintoseveralsoiltopography tpgrfi tpgrfi 地形学地形学,地势地势geological dildikl dildikl 地质学，地质地质学，地质outcrops autkrp autkrp 露头露头paleontological古生物学；古生物学；geophysical地球物理学；地球物理学；electricalresistivity：电阻：电阻 characteristics.第22页Seismic techniques often are used to determine the characteristics of various subsurface strata by measuring the velocity of propagation of explosively generated shock waves through the strata.Thepropagationvelocityvarieswidelyfordifferenttypesofsoils.ShockwavesalsoareutilizedtodeterminethedepthofbedrockbymeasuringthetimerequiredfortheshockwavetotraveltohebedrockandreturnSeismic saizmik saizmik 地震地震 strata streit pl streit pl层层(地层地层,阶层阶层,薄片薄片)stratum:streitm streitm velocity vilsiti vilsiti 速度速度propagation.prpgein .prpgein 传输传输 地震学技术经过测定激震波穿过地层传输速度来确定不地震学技术经过测定激震波穿过地层传输速度来确定不同地层性质。不一样类型传输速度差距是非常大。经过测同地层性质。不一样类型传输速度差距是非常大。经过测定震动波传到基岩和作为反射波回到地面所需时间，可确定定震动波传到基岩和作为反射波回到地面所需时间，可确定基岩深度。基岩深度。tothesurfaceasareflectedwave.第23页 Dependablesubsurfaceinformationcanonlybeobtainedbyexcavation.Aprobe rodpushedintothegroundindicatesthepenetrationresistance.Waterjetsoraugersareusedtobringsubsurfacematerialstothesurfaceforexamination.Colorchangeisoneofthesignificantelementssuchanexaminationcanproberod探测棒探测棒penetration penitrein penitrein 贯入贯入,侵透侵透,auger:g :g 麻花钻麻花钻,钻孔机钻孔机reveal.第24页Variousdrilling methodsareemployedtoobtainchipsfromdepths.Trenchesorpitsprovidemorecompleteinformationforshallowdepths.Pneumaticordiamonddrillingmayberequiredifhardrockisencountered.Atleastafewoftheboreholesshouldexceedthedepthofsignificantstressthatisdrilling drili drili 钻孔钻孔trench trent trent 沟沟pneumatic nju(:)mtik nju(:)mtik 气气动 establishedforthestructure.第25页 Avoidanceofstructuraldisturbanceofthesamplesisnotcriticalforsometestsbutisveryimportantforin-placedensityorshearing strengthmeasurement.Completeandaccuraterecords,suchasborehole logs,mustbepreparedandmaintained,andthesamplesthemselvesmustberetainedforfutureinspection.in-place 原状，原位原状，原位boreholelog测井曲井曲线 第26页