地铁与隧道施工力学2

《地铁与隧道施工力学2》由会员上传分享，免费在线阅读，更多相关内容在教育资源-天天文库。

1、PracticalexampleTunnelsinweakrockEstimateofrockmasspropertiesThisshowsthatthesizeoftheplasticzoneandalsotheinduceddeformationswillbenegligiblysmall.Furthermore,nopermanentsupportshouldberequiredforthetunnel.Forthegranodiorite,GSI=55,mi=30andσci=100Mpa

2、σcirm=23MPa.RockmassstrengthInsitustress=5PracticalexampleTunnelsinweakrockEstimateofrockmasspropertiesForthealteredporphyryandfaultmaterial,GSI=15,mi=12andσci=10Mpa,σcirm=0.4MPa.RockmassstrengthInsitustressifr0=2m,thenrp=9.3mandU=0.4m,substantialsupp

3、ortisrequired.=0.1Experiencesuggests:U/r0<=0.02SupportpressureInsitustress=0.35Supportpressure=1.4MpaShotcreteConcreteliningCloselyspacedsteelsetsSlidingjointtophatsectionsets.PracticalexampleTunnelsinweakrockEstimateofrockmasspropertiesTophatsections

4、teelsetsAssemblyofafrictionjointinatophatsectionsteelsetInstallationofslidingjointtophatsectionsteelsetsimmediatelybehindthefaceofatunnelbeingadvancedthroughverypoorqualityrock.PracticalexampleTunnelsinweakrockEstimateofrockmassproperties1Forepoles–ty

5、pically75or114mmdiameterpipes,12mlonginstalledevery8mtocreatea4moverlapbetweensuccessiveforepoleumbrellas.2Shotcrete–appliedimmediatelybehindthefaceandtotheface,incaseswherefacestabilityisaproblem.Typically,thisinitialcoatis25to50mmthick.3Groutedfiber

6、glassdowels–Installedmidwaybetweenforepoleumbrellainstallationstepstoreinforcetherockimmediatelyaheadoftheface.Thesedowelsareusually6to12mlongandarespacedona1mx1mgrid.4Steelsets–installedasclosetothefaceaspossibleanddesignedtosupporttheforepoleumbrell

7、aandthestressesactingonthetunnel.5Invertstruts–installedtocontrolfloorheaveandtoprovideafootingforthesteelsets.6Shotcrete–typicallysteelfiberreinforcedshotcreteappliedassoonaspossibletoembedthesteelsetstoimprovetheirlateralstabilityandalsotocreateastr

8、ucturallining.7Rockboltsasrequired.Inverypoorqualitygrounditmaybenecessarytouseself-drillingrockboltsinwhichadisposablebitisusedandisgroutedintoplacewiththebolt.8Invertlining–eithershotcreteorconcretecanbeused,dependingupontheenduseofthetunnel