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ID:36640918
大小:1.44 MB
页数:56页
时间:2019-05-13
《软土地区基坑开挖对既有地铁隧道影响的研究》由会员上传分享,免费在线阅读,更多相关内容在学术论文-天天文库。
1、南京林业大学硕士学位论文软土地区基坑开挖对既有地铁隧道影响的研究姓名:钟定兰申请学位级别:硕士专业:森林工程指导教师:杨平20070601AbstractAsthesubwaywhichiswellknownhasbecomeanimportantmeansoftransportinbigcities,thetunnelisinevitabletobeeffectedbybuildingnearit.Thesurfacesettlementscausedbyexcavationandinflue
2、nceonadjacentsubwaytunnelaretheproblemshighlyconcernedinthedesignandconstructionprocessofexcavation.Itissignificanttostudyofinfluenceofexcavatingonanexistingsubwaytunnelinsoftsoilareas.Theeffectsoftheexistingtunnelduringexcavationhasbeensimulatedthro
3、ugh3DFEM,andthedisplacementsofthetunnelhavebeenanalyzedqualitatively.Whencomparedwithmeasureddates,ithasfoundthatthefiniteelementresultshavebeenwellconsistentwithit.TypicalsoftsoilofNanjingareasweresimulatedandanalyzed,through3DFEMithasbeensimulateds
4、everalparameterssuchastherelativeposition,eachkindofoperationsduringthepit,thedifferentdistancefromexcavation,differentdepthandthediaphragmwallatdifferentdepths,thedisplacementsofhorizontalandverticalandcurvesofforcesalongthelongitudinalaxisofthetunn
5、elhavebeenobtained,somemeaningfulconclusionsweregetasfollows:。(1)Underdifferentexcavationconditions,themaximumdisplacementsandthesmallestaxialsandlargestmomentsofthetunnellocatedatz50m.therewasasuddenincreaseofsheararoundz=l5m,thetunnelwasgreaterimpa
6、ctedduringexcavationunloadingand,lesseffectedinconstructingdiaphragmwallandsupporting.Itwouldbeincreasedasthedepthofexcavationincreased.(2)Withtheincreasingofdistance,thedisplacementsofhorizontalweregraduallydecreasedandsmallatabout12mfarfromtheexcav
7、ation.Soastheverticaldisplacements.Whenthetunnelwasneartheexcavation,theaxisforcewasgraduallyincreased.Shearandmomentweregraduallyreduced.SoastheaxisforceandShearwhenthetunnelwasundertheexcavation.Butthemomentwaschangedindirection.(3)Withtheincreasei
8、ndepth,thedisplacementoftunnelincreasesfirstandthendecreases,probablyduetothelargestdisplacementofdiaphragmwalllocatedatO.6H.Itcouldbeseenthatthedisplacementsoftunneldependlargeonthedeformationofthediaphragmwall,itwasnecessarytocontrolthedeformatione
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