一般基坑開挖施工安全應注意哪些？
1．放坡開挖的基坑，其坡度應滿足規范和設計要求。
2．坑壁不加固基坑施工，基坑平面尺寸一般應每邊加寬 0.3 ～0.6m，如遇地下水，還應留出排水溝和集水井的位置，對于垂直開挖的無水基坑，可不加寬。
3、處在土石松動坡腳下的基坑，開挖前要做好防護工作；坑頂四周應做成反坡，并在距離坑緣適當的距離處設截水溝，防止雨水進入基坑；坑緣頂部如果有動載，動載與坑緣之間至少有 1m 寬的護道，地質水文條件不良時，護道要加寬或者采取加固措施；基坑棄土堆至坑緣的距離，要根據具體的地質條件來確定，但不得小于坑的深度。
4、嚴禁采用局部開挖深坑，從底部向四周掏土的方法施工。
5、人力出土時，要按照有關腳手架的規定，搭好出土走道，基坑較深時要搭設上下跳板或梯子；機械開挖時，要按照有關機械的操作規程和規定的信號，專人進行指揮；吊斗要拉溜繩；遇到涌水、涌沙、邊緣坍塌等異常情況，人員要及時撤離，必須在采取了可靠的防護措施后才能繼續施工。
6、基坑開挖要從速進行；在開挖階段，如果出現地基面疏松要視情況夯實，或進行變更；當基坑開挖接近設計標高時，應注意預留 10～20cm，待下道工序準備就緒，在灌注前挖除；基坑開挖后要及時灌注或砌筑基礎圬工，不得長期暴露或浸泡。
7、破碎的石質基坑，要根據巖石構造等情況決定開挖坡度；砂質土層或深度較大的基坑，要在邊坡中段設 1m左右的護道；在開挖過程中要做好排水工作。
8、施工現場開挖溝槽邊緣，與外電埋地電纜溝槽邊緣之間的距離不得小于0.5m。在外電架空線路附近開控溝槽時，必須會同有關部門采取加固措施，防止外電架空線路電桿傾斜、懸倒。
9、坑壁支撐基坑施工，襯板可以緊密鋪設或間隔鋪設，一次挖成或分段挖成，但每次開挖不得超過 2m；如基坑較深時，四周應掛軟梯，在開挖過程中發現異常情況，人員應及時撤離，加固后方可繼續施工；支撐要選用質量良好的木材，在施工中要隨時檢查，并處理受力不均和應力集中等情況；在使用機械出土時，要防止碰撞支撐；在拆除支撐時，要自下而上分段進行。
10、采用鋼筋混凝土圍圈護壁時，除頂層可以一次整體灌注外，往下應根據土質情況，控制開挖高度和長度，并隨開挖隨灌注，其頂部應高出地面 0.5m，并掛好梯子，頂部不得擺放料具
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Pollisanexampleofaseverelydisabledpersonwhohasbecome______atmanysurvivalskills.
WhenthepoliceofficerswhotookpartintheKingbeatingwerefirstbroughtto___________,theirlawyersusedthevideotapeasevidenceagainsttheprosecution.
Iftheoldmaximthatthecustomerisalwaysrightstillhasmeaning,thentheairlinesthatplytheworld’sbusiestairroutebetweenLondonandParishaveaflightontheirhands.
TheEurostartrainservicelinkingtheUKandFrenchcapitalsviatheChannelTunneliswinningcustomersinincreasingnumbers.InlateMay,itcarrieditsonemillionthpassenger,havingrunonlyalimitedservicebetweenLondon,ParisandBrusselssinceNovember1994,startingwithtwotrainsadayineachdirectiontoParisandBrussels.By1997,thecompanybelievesthatitwillbecarryingtenmillionpassengersayear,andcontinuetogrowfromthere.
FromJuly,EurostarstepsitsservicetoninetrainseachwaybetweenLondonandParis,andfivebetweenLondonandBrussels.Eachtraincarriesalmost800passengers,210oftheminfirstclass.
Theairlinesestimatethattheywillinitiallylosearound15%-20%oftheirLondon-ParistraffictotherailwaysonceEurostarstartsafullservicelaterthisyear(1995),with15trainsadayeachway.AsimilarservicewillstarttoBrussels.Thedamagewillbelimited,however,theairlinesbelieve,withpassengernumbersreturningtopreviouslevelswithintwotothreeyears.
Intheshortterm,thedamagecausedbythe1millionpeople-levelstravelingbetweenLondonandParisandBrusselsonEurostartrainsmeansthatsomeairservicesarealreadysuffering.Someofthemajorcarrierssaythattheirpassengernumbersaredownbylessthan5%andpointtotheirrivals-ParticularlyAirFrance-ashavingsufferedtheproblems.OntheBrusselsroute,therailwaycompanyhadlesssuccess,andtheairlinesreportanythingfromarounda5%droptonovisibledeclineintraffic.
Theairlines’optimismonreturningtrafficlevelsisbasedonhistoricalprecedent.BritishMidland,forexample,pointstoitsexperienceonHeathrowLeedsBradfordservicewhichsawpassengernumbersfoldby15%whenBritishRailelectrifiedandmodernizedtherailwaylinebetweenLondonandYorkshire.Twoyearslater,travelhadrisenbetweenthetwodestinationstothepointwheretheairlinewascarryingrecordnumbersofpassengers.
1.Britishairlinesconfideinthefactthat__.
A.theyaremorepowerfulthanotherEuropeanairlines.
B.theirtotallosswon’tgobeyondadropof5%passengers.
C.theirtrafficlevelswillreturnin2-3years.
D.travelingbyrailcannevercatchupwithtravelingbyair.
2.Theauthor’sattitudetowardsthedropofpassengersmaybedescribedas__.
A.worried.B.delightedC.puzzled.D.unrivaled.
3.Inthepassage,BritishRail(Para6)ismentionedto__.
A.provideacomparisonwithEurostar.
B.supporttheairlines’optimism.
C.provetheinevitabledropofairpassengers.
D.callforelectrificationandmodernizationoftherailway.
4.Therailway’sBrusselsrouteisbroughtforthtoshowthat__.
A.theEurostartrainserviceisnotdoinggoodbusiness.
B.theairlinescanwellcompetewiththerailway.
C.theEurostartrainserviceonlycausedlittledamage.
D.onlysomeairlines,suchasAirFrance,aresuffering.
5.Thepassageistakenfromthefirstofanessay,fromwhichwemaywellpredictthatinthefollowingparttheauthorisgoingto__.
A.praisetheairlines’clear-mindedness.
B.warntheairlinesofhigh-speedrailservices.
C.proposeareductionofLondon/Parisflights.
D.advisetheairlinestofollowBritishMidlandastheirmodel.
Her____washeldatthelocalchurch.
You____thatlettertoJames.However，youdidn't.
