基于二次受力的隧道套拱加固损伤衬砌模型试验

Instabilityofcrackedlininginducedbyloosingloadinghasbeenacriticalscientificproblemduringoperationperiodfortunnel.Theloadingdeviceforatwo-lanehighwaytunnelmodeltestswasmanufactured.Thedevicecouldimposeloadonanypositionoflining.Itcanreinforcecrackedliningwhenitisundermechanicalcondition.Itsolvesthe‘bottleneck’problemofsecondaryloadingofreinforcementofcrackinglining.The1∶10modeltestswerecarriedouttoinvestigatestrengtheningeffectbyumbrellaarchunderloosingloading,suchasdeformationcharacteristic,mechanicalresponseandfailuremode.Thestiffnessofliningdeclineswithloadingincreasing.Thereinforcementwithumbrellaarchcanrepaircrackedliningeffectively,andincreaseitsstiffness.Itcanmakethebearingcapacityofseriouslycrackedliningdouble.Theoriginalliningdamagesatarch,spandrelandwall.Thecriticalcontrolledsectionsofumbrellaarcharearchandwall-footing.Compressive-bentdamageoflargeeccentricitytakesplaceatarch.Heavyreinforcementsaresuggestedforarchtoimprovetensilestrength.Diagonal crackandcompressive-shearappearatwall-footing.Sostirrupofwall-footingshouldbesupplementedtoupdateultimateshearingbearingcapacity.