汶川特大地震中山岭隧道变形破坏特征及影响因素分析.pdf

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1、JournalofEngineeringGeology工程地质学报1004—9665／2008／16(6)-0742-09汶川特大地震中山岭隧道变形破坏特征及影响因素分析李天斌(成都理工大学地质灾害防治与地质环境保护国家重点实验室成都610059)摘要汶川大地震造成位于震中附近的都江堰一汶川公路多座隧道严重受损。本文通过现场调研、资料收集与分析，将地震区山岭隧道变形破坏的基本类型概括为洞13边坡崩塌与滑塌、洞门裂损、衬砌及围岩坍塌、衬砌开裂及错位、底板开裂及隆起、初期支护变形及开裂等。分析其影响因素，认为发震断裂的次级断层、基覆

2、界面、洞口不稳定斜坡、高地应力环境下的软弱围岩对隧道强烈震害具有控制作用。以汶川地震给予隧道抗震的启示，建议强震区的山岭隧道应将洞口边坡防护、洞口明洞和洞门结构作为一个系统进行综合设计，在条件允许的情况下尽可能采用削竹式洞门结构；隧道穿越活动断裂带的次级断层时在其两侧一定范围内二次衬砌应采用钢筋混凝土结构；基覆界面、围岩软岩与硬岩之间的过渡地带、围岩质量突变地带等应采用改善围岩力学性质且让其渐变的措施进行处理。关键词汶川地震山岭隧道震害影响因素抗震启示中图分类号：U453文献标识码：AFAILURECHARACTERISTICS

3、AND胂LUENCEFACToRANALYSISOFMoUNTAINTUNNELSATEPICENTERZoNESoFGREATWENCHUANEARTHQUAKELlTianbin(StateKeyLaboratoryofGeo—HazardPreventionandGeo—EnvironmentProtection。ChengduUniversityofTechnology-Chengdu610059)AbstractrhegreatWenchuanEarthquakeofMs8．0gradetookplaceintheLo

4、ngmenshanfaultzoneofwesternSichuanProvinceonMay12，2008．ManytunnelsonthehighwayfromDujiangyantoWenchuanweredamagedse—verelyduetothesitelocatedneartheepicenter．Throughtheon—siteinvestigationandresearch，thedatacosec—tionandanalysis，thispaperillustratesthefailuretypesand

5、characteristicsofthemountaintunnelsinthesevereearthquakeregion．Itfurthersummarizesthebasictypesastheavalancheandslidingoftunnelopening，therhegmaoftunnelportal，thecollapseoflinerandsurroundingrock，thecrackanddislocationofliner，theupliftandcrackofarchinvert，thedeformat

6、ionandcrackofpreliminarybracing．Then，theinfluencingfactorsofthetunnelseismicdamagesarediscussedbytakingintoaccountespeciallythecontrollingfunctionsofthesecondaryfaultsofearth-quakefractures，thecontactzonebetweencoverandbedrock，theunstableslopeinthetunnelface，andthewe

7、aksuroundingrockinhighgeostressenvironmentonthestrongseismicdamages．Finally，somerevelationsofthetun—nelearthquake—-resistancearesummarizedbasedonthenaturalresuhsofthemountaintunneldamagesinWen·-chuanEarthquake．Itissuggestedthatinstrongearthquakeareas，acomprehensiveas

8、eismicdesignbeconductedconsideringtheslopeoftunnelface，nakedtunnelandtunnelportalstructureasasystem．Fortunnelcrossingthe收稿日期：2008—1