Seismic design and analysis of underground structu

Ž.TunnellingandUndergroundSpaceTechnology162001247
293ITA
AITESAccreditedMaterialSeismicdesignandanalysisofundergroundstructuresYoussefM.A.Hashasha,
,JeffreyJ.Hooka,BirgerSchmidtb,JohnI-ChiangYaoaaDepartmentofCiilandEnironmentalEngineering,UniersityofIllinoisatUrbana-Champaign,205N.MathewsAenue,MC-250,Urbana,IL61801,USAbParsonsBrinckerhoff,SanFrancisco,CA,USAAbstractUndergroundfacilitiesareanintegralpartoftheinfrastructureofmodernsocietyandareusedforawiderangeofapplications,includingsubwaysandrailways,highways,materialstorage,andsewageandwatertransport.Undergroundfacilitiesbuiltinareassubjecttoearthquakeactivitymustwithstandbothseismicandstaticloading.Historically,undergroundfacilitieshaveexperiencedalowerrateofdamagethansurfacestructures.Nevertheless,someundergroundstructureshaveexperiencedsignificantdamageinrecentlargeearthquakes,includingthe1995Kobe,Japanearthquake,the1999Chi-Chi,Taiwanearthquakeandthe1999Kocaeli,Turkeyearthquake.Thisreportpresentsasummaryofthecurrentstateofseismicanalysisanddesignforundergroundstructures.Thisreportdescribesapproachesusedbyengineersinquantifyingtheseismiceffectonanundergroundstructure.Deterministicandprobabilisticseismichazardanalysisapproachesarereviewed.Thedevelopmentofappropriategroundmotionparameters,includingpeakaccelerationsandvelocities,targetresponsespectra,andgroundmotiontimehistories,isbrieflydescribed.Ingeneral,seismicdesignloadsforundergroundstructuresarecharacterizedintermsofthedeformationsandstrainsimposedonthestructurebythesurroundingground,oftenduetotheinteractionbetweenthetwo.Incontrast,surfacestructuresaredesignedfortheinertialforcescausedbygroundaccelerations.Thesimplestapproachistoignoretheinteractionoftheundergroundstructurewiththesurroundingground.Thefree-fieldgrounddeformationsduetoaseismiceventareestimated,andtheundergroundstructureisdesignedtoaccommodatethesedeformations.Thisapproachissatisfactorywhenlowlevelsofshakingareanticipatedortheundergroundfacilityisinastiffmediumsuchasrock.Otherapproachesthataccountfortheinteractionbetweenthestructuralsupportsandthesurroundinggroundarethendescribed.Inthepseudo-staticanalysisapproach,thegrounddeformationsareimposedasastaticloadandthesoil-structureinteractiondoesnotincludedynamicorwavepropagationeffects.Inthedynamicanalysisapproach,adynamicsoilstructureinteractionisconductedusingnumericalanalysistoolssuchasfiniteelementorfinitedifferencemethods.Thereportdiscussesspecialdesignissues,includingthedesignoftunnelsegmentjointsandjointsbetweentunnelsandportalstructures.Examplesofseismicdesignusedforundergroundstructuresareincludedinanappendixattheendofthereport.
2001ElsevierScienceLtd.Allrightsreserved.Keywords:Seismicdesign;Seismicanalysis;Undergroundstructures;Tunnels;Subways;Earthquakedesign
Correspondingauthor.Tel.:1-217-333-6986;fax:1-217-265-8041.Ž.E-mailaddress:[e-mail].0886-7798
01
$-seefrontmatter
2001ElsevierScienceLtd.Allrightsreserved.Ž.PII:S0886-77980100051-7()Y.M.A.Hashashetal.
TunnellingandUndergroundSpaceTechnology162001247
293248PrefaceThispaperwasdevelopedaspartoftheactivitiesof()theInternationalTunnellingAssociationITAWorkingGroupNo2:Research.Thepaperprovidesastate-of-the-artreviewofthedesignandanalysisoftunnelssubjecttoearthquakeshakingwithparticularfocusonpracticeintheUnitedStatesofAmerica.TheAuthorswishtoacknowledgetheimportantcontributionofWorkingGroup2membersincludingMr.YannLeblais,Animateur,YoshihiroHiroTakano,Vice-Animateur,BarryNew,Member,HenkJ.C.OudandAndresAssis,TutorandFormerTutor,respectively,aswellastheITAExecutiveCouncilfortheirreviewandapprovalofthisdocument.1.IntroductionUndergroundstructureshavefeaturesthatmaketheirseismicbehaviordistinctfrommostsurfacestruc-Ž.tures,mostnotably1theircompleteenclosureinsoilŽ.Ž.orrock,and2theirsignificantlengthi.e.tunnels.Thedesignofundergroundfacilitiestowithstandseismicloadingthus,hasaspectsthatareverydifferentfromtheseismicdesignofsurfacestructures.Thisreportfocusesonrelativelylargeundergroundfacilitiescommonlyusedinurbanareas.Thisincludeslarge-diametertunnels,cut-and-coverstructuresandŽ.portalstructuresFig.1.Thisreportdoesnotdiscusspipelinesorsewerlines,nordoesitspecificallydiscussissuesrelatedtodeepchamberssuchashydropowerplants,nuclearwasterepositories,minechambers,andprotectivestructures,thoughmanyofthedesignmeth-odsandanalysesdescribedareapplicabletothedesignofthesedeepchambers.Large-diametertunnelsarelinearundergroundstructuresinwhichthelengthismuchlargerthanthecross-sectionaldimension.Thesestructurescanbegroupedintothreebroadcategories,eachhavingdis-Ž.tinctdesignfeaturesandconstructionmethods:1Ž.boredorminedtunnels;2cut-and-covertunnels;andŽ.Ž.3immersedtubetunnelsPoweretal.,1996.Thesetunnelsarecommonlyusedformetrostructures,high-waytunnels,andlargewaterandsewagetransportationducts.Boredorminedtunnelsareuniquebecausetheyareconstructedwithoutsignificantlyaffectingthesoilorrockabovetheexcavation.TunnelsexcavatedusingŽ.tunnel-boringmachinesTBMsareusuallycircular;othertunnelsmayberectangularorhorseshoeinshape.Situationswhe