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1、第36卷第5期岩土力学Vol.36No.52015年5月RockandSoilMechanicsMay2015DOI:10.16285/j.rsm.2015.05.025大断面深埋高水压地铁盾构隧道周边土压力作用模式评价1112李雪,周顺华,宫全美,陈长江(1.同济大学道路与交通工程教育部重点实验室,上海201804;2.中铁隧道勘测设计院有限公司,天津300133)摘要:以南京某大直径地铁盾构隧道为背景,对盾构管片衬砌所受荷载及结构内力进行现场测试,分析了深埋高水压粉细砂地层中盾构隧道管片土压力大小及分布特征。采用3种
2、不同竖向荷载组合(即有效上覆土压力+水压力,太沙基松动土压力+水压力,只有水压力)计算管片内力并与实测内力进行比较,评价了作用在盾构隧道管片上的土压力模式。结果表明:(1)作用在盾构隧道衬砌上的水压力大小基本等于静止水压力;(2)盾构隧道隧顶实测土压力约为太沙基松动土压力的80%,实测隧顶土压力更接近于太沙基松动土压力,隧道上方存在土拱;(3)现场实测管片弯矩较3种荷载作用下计算弯矩小,而实测管片轴力约为理论计算轴力的2倍。此外,分析了水平地基抗力系数对隧道管片内力的影响。研究成果可为大直径深埋盾构隧道设计提供参考。关键
3、词:盾构隧道;深埋大断面;现场监测;土压力中图分类号:U455.43文献识别码:A文章编号:1000-7598(2015)05-1415-07Evaluationofearthpressurearoundadeeplyburiedmetroshieldtunnelwithalargecross-sectionunderhighwaterpressureconditions1112LIXue,ZHOUShun-hua,GONGQuan-mei,CHENChang-jiang(1.KeyLaboratoryofRoadand
4、TrafficEngineering,MinistryofEducation,TongjiUniversity,Shanghai201804,China;2.ChinaRailwayTunnelSurvey&DesignInstituteCo.,Ltd.,Tianjin300133,China)Abstract:Afieldmonitoringprogramisperformedtomeasuretheearthpressuresactingontheliningsandtheinternalforcesinsegmen
5、tsofaslurryshieldtunnelofYangtzeRivertunnelprojectinNanjing.Themagnitudeanddistributionoftheearthpressureareanalyzedaroundthetunneldeeplyburiedinasiltysandstratumwithhighporewaterpressure.Theinternalforcesinthesegmentsofconcernarecalculatedunderthreedifferentvert
6、icalloadingcombinations(i.e.effectiveoverlyingsoilpressurepluswaterpressure,Terzaghi’ssoilpressurepluswaterpressure,andwaterpressureonly),andtheresultsarecomparedtotheonesmeasuredinthefield.Theresultsshowthat:1)thewaterpressureactingontheshieldtunnelliningisalmos
7、tequaltothetheoreticalhydrostaticpressure;2)theobservedverticalearthpressureonthecrownofshieldtunnelaccountsforabout80%ofthatyieldbytheTerzaghi’ssoilpressurepluswaterpressureformulation,showingsoilarchingeffectexistsabovethetunnel;3)theobservedbendingmomentsaresm
8、allerthantheoreticalresultsofthethreecombinationmethods,andthemeasuredaxialforcesareapproximatelytwiceasmuchasthetheoreticalresults.Inaddition,theinfluenceofth