土木工程外文翻译 2.docx
- 文档编号:20770680
- 上传时间:2023-04-25
- 格式:DOCX
- 页数:10
- 大小:21.83KB
土木工程外文翻译 2.docx
《土木工程外文翻译 2.docx》由会员分享,可在线阅读,更多相关《土木工程外文翻译 2.docx(10页珍藏版)》请在冰豆网上搜索。
土木工程外文翻译2
毕业设计外文翻译
建筑工程学院工程管理专业
学生姓名王xx
班级工程管理
指导教师过老师
教研室主任于老师
2016年2月22日
DESIGNANDEXECUTIONOFGROUNDINVESTIGATIONFOREARTHWORKS
1.INTRODUCTION
Theinvestigationandre-useevaluationofmanyIrishboulderclaysoilspresentsdifficultiesforboththegeotechnicalengineerandtheroaddesignengineer.Theseglacialtillorboulderclaysoilsaremainlyoflowplasticityandhaveparticlesizesrangingfromclaytoboulders.Mostofourboulderclaysoilscontainvaryingproportionsofsand,gravel,cobblesandbouldersinaclayorsiltmatrix.Theamountoffinesgovernstheirbehaviourandthesiltcontentmakesitveryweathersusceptible.
Moisturecontentscanbehighlyvariablerangingfromaslowas7%forthehardgreyblackDublinboulderclayupto20-25%forMidland,South-WestandNorth-Westlightgreyboulderclaydeposits.Theabilityofboulderclaysoilstotake-infreewateriswellestablishedandpoorplanningofearthworksoftenamplifiesthis.
Thefinesoilconstituentsaregenerallysensitivetosmallincreasesinmoisturecontentwhichoftenleadtolossinstrengthandrenderthesoilsunsuitableforre-useasengineeringfill.Manyofourboulderclaysoils(especiallythosewithintermediatetypesiltsandfinesandmatrix)havebeenrejectedattheselectionstage,butgoodplanningshowsthattheycaninfactfulfilspecificationrequirementsintermsofcompactionandstrength.
Theselectionprocessshouldaimtomaximisetheuseoflocallyavailablesoilsandwithcarefulevaluationitispossibletouseorincorporate‘poorormarginalsoils’withinfillareasandembankments.Fillmaterialneedstobeplacedatamoisturecontentsuchthatitisneithertoowettobestableandtrafficableortoodrytobeproperlycompacted.
Highmoisturecontent/lowstrengthboulderclaysoilscanbesuitableforuseasfillinlowheightembankments(i.e.2to2.5m)butnotsuitablefortraffickingbyearthworkplantwithoutusingageotextileseparatorandgranularfillcappinglayer.Hence,itisvitalthattheearthworkscontractorfullyunderstandsthehandlingpropertiesofthesoils,asformanyprojectsthisiseffectivelygovernedbythetrafficabilityofearthmovingequipment.
2.TRADITIONALGROUNDINVESTIGATIONMETHODS
Forroadprojects,aprincipalaimofthegroundinvestigationistoclassifythesuitabilityofthesoilsinaccordancewithTable6.1fromSeries600oftheNRASpecificationforRoadWorks(SRW),March2000.Themajorityofcurrentgroundinvestigationsforroadworksincludesacombinationofthefollowingtogivetherequiredgeotechnicaldata:
▪Trialpits
▪Cablepercussionboreholes
▪Dynamicprobing
▪Rotarycoredrilling
▪In-situtesting(SPT,variableheadpermeabilitytests,geophysicaletc.)
▪Laboratorytesting
Theimportanceof‘phasing’thefieldworkoperationscannotbeoverstressed,particularlywhenassessingsoilsuitabilityfromdeepcutareas.Cablepercussionboreholesarenormallysunktoadesireddepthor‘refusal’withdisturbedandundisturbedsamplesrecoveredat1.00mintervalsorchangeofstrata.
Inmanyinstances,cablepercussionboringisunabletopenetratethroughverystiff,hardboulderclaysoilsduetocobble,boulderobstructions.Sampledisturbanceinboreholesshouldbepreventedandlossoffinesiscommon,invariablythisleadstoinaccurateclassification.
Trialpitsareconsideredmoreappropriateforrecoveringappropriatesizesamplesandforobservingtheproportionofclaststomatrixandsizesofcobbles,boulders.Detailedandaccuratefielddescriptionsarethereforevitalforcutareasandtrialpitsprovideanopportunitytoexaminethesoilsonalargerscalethanboreholes.Trialpitsalsoprovideaninsightontrenchstabilityandtoobservewateringressanditseffects.
Asuitablyexperiencedgeotechnicalengineerorengineeringgeologistshouldsupervisethetrialpittingworksandrecoveryofsamples.Thecharacteristicsofthesoilsduringtrialpitexcavationshouldbecloselyobservedasthisprovidesinformationonsoilsensitivity,especiallyifwaterfromgranularzonesmigratesintothefinematrixmaterial.Veryoften,theconditionofsoilonthesidesofanexcavationprovidesamoreaccurateassessmentofitsin-situcondition.
3.ENGINEERINGPERFORMANCETESTINGOFSOILS
Laboratorytestingisverymuchdictatedbytheproposedend-useforthesoils.TheengineeringparameterssetoutinTable6.1pftheNRASRWincludeacombinationofthefollowing:
▪Moisturecontent
▪Particlesizegrading
▪PlasticLimit
▪CBR
▪Compaction(relatingtooptimumMC)
▪Remouldedundrainedshearstrength
Anumberofkeyfactorsshouldbeborneinmindwhenschedulinglaboratorytesting:
▪Compaction/CBR/MCVtestsarecarriedouton<20mmsizematerial.
▪Moisturecontentvaluesshouldrelateto<20mmsizematerialtoprovideavalidcomparison.
▪Porepressuresarenottakenintoaccountduringcompactionandmayvaryconsiderablybetweenlaboratoryandfield.
▪Preparationmethodsforsoiltestingmustbeclearlystipulatedandagreedwiththedesignatedlaboratory.
Greatcaremustbetakenwhendeterminingmoisturecontentofboulderclaysoils.Ideally,themoisturecontentshouldberelatedtotheparticlesizeandhaveacorrespondinggradinganalysisfordirectcomparison,althoughthisisnotalwayspractical.
Inthemajorityofcases,theMCVwhenusedwithcompactiondataisconsideredtoofferthebestmethodofestablishing(andchecking)thesuitabilitycharacteristicsofaboulderclaysoil.MCVtestingduringtrialpittingisstronglyrecommendedasitprovidesarapidassessmentofthesoilsuitabilitydirectlyafterexcavation.MCVcalibrationcanthenbecarriedoutinthelaboratoryatvariousmoisturecontentincrements.SampledisturbancecanoccurduringtransportationtothelaboratoryandthiscanhaveasignificantimpactontheresultantMCV’s.
IGSLhasfoundlargediscrepancieswhenperformingMCV’sinthefieldonlowplasticityboulderclayswiththosecarriedoutlaterinthelaboratory(2to7days).ManyoftheaforementionedlowplasticityboulderclaysoilsexhibittimedependantbehaviourwithsignificantlydifferentMCV’srecordedatalaterdate–increasedvaluescanbeduetothedrainageofthematerialfollowingsampling,transportationandstoragewhiledilatancyandmigrationofwaterfromgranularlensescanleadtodeteriorationandlowervalues.
Thistypeofinformationisimportanttoboththedesignerandearthworkscontractorasitprovidesanopportunitytounderstandthepropertiesofthesoilswhentestedasoutlinedabove.Itcanalsoillustratetheadvantagesofpre-draininginsomeinstances.Withmixedsoils,faceexcavationmaybenecessarytoacceleratedrainageworks.
CBRtestingofboulderclaysoilsalsoneedscarefulconsideration,mainlywiththepreparationmethodemployed.Designengineersneedtobeawareofthis,asitcanhaveanorderofmagnitudedifferenceinresults.Staticcompactionofboulderclaysoilsisadvisedascompactionwiththe2.5or4.5kgrammeroftenleadstohighexcessporepressuresbeinggenerated–henceverylowCBRvaluescanresult.Also,curingofcompactedboulderclaysamplesisimportantasthisallowsexcessporewaterpressurestodissipate.
4.ENGINEERINGCLASSIFICATIONOFSOILS
InaccordancewiththeNRASRW,generalcohesivefilliscategorisedinTable6.1asfollows:
▪2AWetcohesive
▪2BDrycohesive
▪2CStonycohesive
▪2DSiltycohesive
Thematerialpropertiesrequiredforacceptabilityaregivenandthedesignengineerthendeterminestheupperandlowerboundlimitsonthebasisofthelaboratoryclassificationandengineeringperformancetests.IrishboulderclaysoilsarepredominantlyClass2C.
Clause612oftheSRWsetsoutcompactionmethods.Twoproceduresareavailable:
▪MethodCompaction
▪End-ProductCompaction
Endproductcompactionisconsideredmorepractical,especiallywhengoodcompactioncontroldatabecomesavailableduringtheearlystagesofanearthworkscontract.AminimumTargetDryDensity(TDD)isconsideredveryusefulforthecontractortoworkwithasameansofcheckingcompactionquality.Oncethematerialhasbeenapprovedandmeetstheacceptabilitylimits,thenin-situdensitycanbemeasured,preferablybynucleargaugeorsandreplacementtestswherethestonecontentislow.
Asplacingandcompactionofthefillprogresses,thein-situTDDcanbecheckedandnon-conformingareasquicklyrecognisedandcorrectiveactiontaken.Thisprocessrequiresthedesignengineertoreviewthefielddensitieswiththelaboratorycompactionplotsandevaluateactualwith‘theoreticaldensities’.
5.SUPPLEMENTARYGROUNDINVESTIGATIONMETHODSFOREARTHWORKS
ThemoretraditionalmethodsandprocedureshavebeenoutlinedinSection2.Thefollowingareexamplesofmethodswhicharebelievedtoenhancegroundinvestigationworksforroadprojects:
▪Phasingthegroundinvestigationworks,particularlythelaboratorytesting
▪Excavation&samplingindeeptrialpits
▪Largediameterhighqualityrotarycoredrillingusingair-mistorpolymergeltechniques
中文译文:
土方工程的地基勘察与施工
1、引言
许多爱尔兰含砾粘土的勘察与再利用评价使岩土工程师与道路工程师感到为难。
这些冰渍土或含砾粘土主要表现为低可塑性而且还含有从粘土到漂石的不同粒径颗粒。
大部分本地粘土与淤泥质土中包含不同比例的砂、砾石、卵石、漂石。
颗粒级配控制着土体的行为,而且淤泥使土体性质易受天气变化影响。
土体含水量随着地区不同而不同,从都柏林硬灰黑含砾粘土的7%到中部、西南部或西北部浅灰色含砾粘土沉积物的20%-25%。
含砾粘土吸附水的能力建立的较好但土方工程中计划的不恰当常导致其扩大。
一般来说,良好级配的土体对于含水量的轻微变大相当敏感,将导致强度下降或不适合用作工程回填土。
许多含砾粘土(尤其中等淤泥质土或良好级配的砂)在选择阶段已经被筛除,但事实上它们能对压缩或强度起到特定的作用。
筛选过程应尽量使用本地土体或者回填区或路堤边性质相对较差的土体,通过仔细评价应加以应用。
回填材料必须保持一定的含水量,既不能太湿导致土体不稳定也不能太干以致不能被充分压缩。
高含水量、低强度含砾粘土适用于低路堤回填(相当于2到2.5米的高度)但不适用于没有使用土工织布隔离与回填层的土方回填工程。
因此,土方工程承包商充分认识土体的处理特性
- 配套讲稿:
如PPT文件的首页显示word图标,表示该PPT已包含配套word讲稿。双击word图标可打开word文档。
- 特殊限制:
部分文档作品中含有的国旗、国徽等图片,仅作为作品整体效果示例展示,禁止商用。设计者仅对作品中独创性部分享有著作权。
- 关 键 词:
- 土木工程外文翻译 土木工程 外文 翻译