中英文對(duì)照外文翻譯文獻(xiàn)(文檔含英文原文和中文翻譯)DESIGNANDEXECUTIONOFGROUNDINVESTIGATIONFOREARTHWORKS1.INTRODUCTIONTheinvestigationandre-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.TRADITIONALGROUNDINVESTIGATIONMETHODSForroadprojects,aprincipalaimofthegroundinvestigationistoclassifythesuitabilityofthesoilsinaccordancewithTable6.1fromSeries600oftheNRASpecificationforRoadWorks(SRW),March2000.Themajorityofcurrentgroundinvestigationsforroadworksincludesacombinationofthefollowingtogivetherequiredgeotechnicaldata:TrialpitsCablepercussionboreholesDynamicprobingRotarycoredrillingIn-situtesting(SPT,variableheadpermeabilitytests,geophysicaletc.)LaboratorytestingTheimportanceof‘phasing’thefieldworkoperationscannotbeoverstressed,particularlywhenassessingsoilsuitabilityfromdeepcutareas.Cablepercussionboreholesarenormallysunktoadesireddepthor‘refusal’withdisturbedandundisturbedsamplesrecoveredat1.00mintervalsorchangeofstrata.Inmanyinstances,cablepercussionboringisunabletopenetratethroughverystiff,hardboulderclaysoilsduetocobble,boulderobstructions.Sampledisturbanceinboreholesshouldbepreventedandlossoffinesiscommon,invariablythisleadstoinaccurateclassification.Trialpitsareconsideredmoreappropriateforrecoveringappropriatesizesamplesandforobservingtheproportionofclaststomatrixandsizesofcobbles,boulders.Detailedandaccuratefielddescriptionsarethereforevitalforcutareasandtrialpitsprovideanopportunitytoexaminethesoilsonalargerscalethanboreholes.Trialpitsalsoprovideaninsightontrenchstabilityandtoobservewateringressanditseffects.Asuitablyexperiencedgeotechnicalengineerorengineeringgeologistshouldsupervisethetrialpittingworksandrecoveryofsamples.Thecharacteristicsofthesoilsduringtrialpitexcavationshouldbecloselyobservedasthisprovidesinformationonsoilsensitivity,especiallyifwaterfromgranularzonesmigratesintothefinematrixmaterial.Veryoften,theconditionofsoilonthesidesofanexcavationprovidesamoreaccurateassessmentofitsin-situcondition.3.ENGINEERINGPERFORMANCETESTINGOFSOILSLaboratorytestingisverymuchdictatedbytheproposedend-useforthesoils.TheengineeringparameterssetoutinTable6.1pftheNRASRWincludeacombinationofthefollowing:MoisturecontentParticlesizegradingPlasticLimitCBRCompaction(relatingtooptimumMC)RemouldedundrainedshearstrengthAnumberofkeyfactorsshouldbeborneinmindwhenschedulinglaboratorytesting: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.ENGINEERINGCLASSIFICATIONOFSOILSInaccordancewiththeNRASRW,generalcohesivefilliscategorisedinTable6.1asfollows:2AWetcohesive2BDrycohesive2CStonycohesive2DSiltycohesiveThematerialpropertiesrequiredforacceptabilityaregivenandthedesignengineerthendeterminestheupperandlowerboundlimitsonthebasisofthelaboratoryclassificationandengineeringperformancetests.IrishboulderclaysoilsarepredominantlyClass2C.Clause612oftheSRWsetsoutcompactionmethods.Twoproceduresareavailable:MethodCompactionEnd-ProductCompactionEndproductcompactionisconsideredmorepractical,especiallywhengoodcompactioncontroldatabecomesavailableduringtheearlystagesofanearthworkscontract.AminimumTargetDryDensity(TDD)isconsideredveryusefulforthecontractortoworkwithasameansofcheckingcompactionquality.Oncethematerialhasbeenapprovedandmeetstheacceptabilitylimits,thenin-situdensitycanbemeasured,preferablybynucleargaugeorsandreplacementtestswherethestonecontentislow.Asplacingandcompactionofthefillprogresses,thein-situTDDcanbecheckedandnon-conformingareasquicklyrecognisedandcorrectiveactiontaken.Thisprocessrequiresthedesignengineertoreviewthefielddensitieswiththelaboratorycompactionplotsandevaluateactualwith‘theoreticaldensities’.5.SUPPLEMENTARYGROUNDINVESTIGATIONMETHODSFOREARTHWORKSThemoretraditionalmethodsandprocedureshavebeenoutlinedinSection2.Thefollowingareexamplesofmethodswhicharebelievedtoenhancegroundinvestigationworksforroadprojects:Phasingthegroundinvestigationworks,particularlythelaboratorytestingExcavation&samplingindeeptrialpitsLargediameterhighqualityrotarycoredrillingusingair-mistorpolymergeltechniques譯文：土方工程的地基勘察與施工1、引言許多愛(ài)爾蘭含礫粘土的勘察與再利用評(píng)價(jià)使巖土工程師與道路工程師感到為難。這些冰漬土或含礫粘土主要表現(xiàn)為低可塑性而且還含有從粘土到漂石的不同粒徑顆粒。大部分本地粘土與淤泥質(zhì)土中包含不同比例的砂、礫石、卵石、漂石。顆粒級(jí)配控制著土體的行為，而且淤泥使土體性質(zhì)易受天氣變化影響。土體含水量隨著地區(qū)不同而不同，從都柏林硬灰黑含礫粘土的7%到中部、西南部或西北部淺灰色含礫粘土沉積物的20%-25%。含礫粘土吸附水的能力建立的較好但土方工程中計(jì)劃的不恰當(dāng)常導(dǎo)致其擴(kuò)大。一般來(lái)說(shuō)，良好級(jí)配的土體對(duì)于含水量的輕微變大相當(dāng)敏感，將導(dǎo)致強(qiáng)度下降或不適合用作工程回填土。許多含礫粘土（尤其中等淤泥質(zhì)土或良好級(jí)配的砂）在選擇階段已經(jīng)被篩除，但事實(shí)上它們能對(duì)壓縮或強(qiáng)度起到特定的作用。篩選過(guò)程應(yīng)盡量使用本地土體或者回填區(qū)或路堤邊性質(zhì)相對(duì)較差的土體，通過(guò)仔細(xì)評(píng)價(jià)應(yīng)加以應(yīng)用。回填材料必須保持一定的含水量，既不能太濕導(dǎo)致土體不穩(wěn)定也不能太干以致不能被充分壓縮。高含水量、低強(qiáng)度含礫粘土適用于低路堤回填（相當(dāng)于2到2.5米的高度）但不適用于沒(méi)有使用土工織布隔離與回填層的土方回填工程。因此，土方工程承包商充分認(rèn)識(shí)土體的處理特性相當(dāng)重要，因?yàn)樵S多工程都受到挖掘設(shè)備通行能力的影響。2、傳統(tǒng)地基勘察方法對(duì)于道路工程來(lái)講，地基勘察最基本目標(biāo)是對(duì)土體適用性進(jìn)行類似表6.1的分類，該表源于國(guó)家檔案登記處2000年3月版的道路施工規(guī)范。目前大部分道路施工中的地基勘察包含以下提供有關(guān)巖土參數(shù)的試驗(yàn)方法：◆取樣孔◆靜壓法取樣◆動(dòng)力探測(cè)◆回轉(zhuǎn)鉆進(jìn)◆原位測(cè)試（標(biāo)準(zhǔn)貫入試驗(yàn)，變水頭滲透試驗(yàn)，巖土物理試驗(yàn)等）室內(nèi)試驗(yàn)評(píng)價(jià)場(chǎng)地工作的重要性特別是評(píng)價(jià)土體深部取樣區(qū)域的適用性時(shí)不能過(guò)分強(qiáng)調(diào)其適用性。靜壓法取樣通常將取樣器下沉至要求深度進(jìn)行取樣，并每間隔一米進(jìn)行取樣。在許多情況下，靜壓法取樣由于卵石、漂石阻礙不能壓入非常堅(jiān)硬的含礫粘土。土樣在鉆孔內(nèi)應(yīng)盡量少擾動(dòng)，但級(jí)配變壞是很正常的，級(jí)配變壞將導(dǎo)致土樣分類不夠精確。取樣孔對(duì)于恢復(fù)適當(dāng)尺寸的土樣以及觀察碎屑巖在卵石、漂石中所占比例來(lái)說(shuō)應(yīng)該是適當(dāng)?shù)?。因此，詳盡且精確的地區(qū)描述取樣區(qū)域以及取樣空來(lái)說(shuō)都相當(dāng)重要，而且還為它們提供了檢查土體在鉆孔范圍以外性質(zhì)的良機(jī)。取樣孔也提供了孔壁穩(wěn)定性的評(píng)價(jià)以及觀察孔壁內(nèi)水進(jìn)入時(shí)所造成的影響。一位有經(jīng)驗(yàn)的巖土工程師或工程地質(zhì)專家應(yīng)監(jiān)督取樣孔工作以及土樣的恢復(fù)。因?yàn)橥翗有再|(zhì)為土樣敏感性提供了信息，所以取樣時(shí)土體性質(zhì)應(yīng)被密切關(guān)注，尤其是水從小顆粒區(qū)域遷移到良好級(jí)配區(qū)域。而且土體在開(kāi)挖時(shí)的條件為其原位條件提供了一個(gè)相對(duì)精確的評(píng)價(jià)。3、土工試驗(yàn)由于室內(nèi)試驗(yàn)的許多規(guī)定使其被建議用作土的最后試驗(yàn)。土的工程參數(shù)列于表6.1，該表源于國(guó)家檔案登記處2000年3月版的道路施工規(guī)范。其中包含以下內(nèi)容：◆含水量◆顆粒級(jí)配◆塑限◆加州承載比◆密實(shí)度（最優(yōu)含水量）◆重塑土不排水抗剪強(qiáng)度當(dāng)進(jìn)行室內(nèi)試驗(yàn)時(shí)，大量的關(guān)鍵因素應(yīng)該被考慮?！裘軐?shí)度.加州承載比.MCV試驗(yàn)土樣小于20mm?！艉繙y(cè)試試樣應(yīng)小于20mm以提供真實(shí)有效的對(duì)比。壓縮時(shí)孔隙壓力未加以