映秀—卧龙公路沿线汶川地震地质灾害研究.pdf

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1、JournalofEngineeringGeology工程地质学报1004-9665／2010／18(2)一0160—08映秀一卧龙公路沿线汶川地震地质灾害研究程强吴事贵苏玉杰(四川省交通厅公路规划勘察设计研究院成都610041)摘要映秀一卧龙公路是汶川地震灾区距震中最近、震害最为严重的一条公路，本文对沿线地震地质灾害进行了详细的调查研究。依据震害特征，将沿线震害划分为斜坡中上部强风化岩体及土层失稳、结构面切割岩体崩滑失稳、滑坡、泥石流等4类，并分析了沿线震害发育规律。调查表明：龙门山后⋯断裂两侧地震地质灾害呈现显著的差异性，主要是由深大断裂的消震隔震效应，地

2、貌放大效应，地质结构等三方面因素决定的。通过134条实测剖面分析，研究了地震失稳斜坡坡度和失稳部位。地震诱发失稳斜坡坡度在33。～84。之间，主要分布在41。～65。之间，可以认为地震诱发斜坡失稳灾害主要发生在4o。以上的斜坡。斜坡失稳部位主要分布在斜坡中上部以及地貌突出部位，主要失稳部位在0．4坡高以上。从研究斜坡动力失稳的角度，将沿线斜坡划分为基岩一土层及强风化层斜坡地质结构、不利外倾结构面基岩斜坡地质结构、块状构造基岩斜坡地质结构、块碎石土层斜坡地质结构等几种地质结构模型，分析论述了各种地质结构相应的地震地质灾害类型及特点。关键词汶川地震地震地质灾害斜坡

3、地质结构模型失稳坡度失稳部位影响因素中图分类号：P65文献标识码：AGEoLoGICALHAZARDSDUEToWENCHUANEARTHQUAKEALoNGYINGXIUTOWOLoNGHIGHWAYCHENGQiangWUShiguiSUYujie(SichuanProvincialCommunicationDepartmentHighwayPlanningSurveyDesignResearchImtit~e，Chengdu610041)AbstractThehighwayfromYingxiutowntoWolongtownisthenearesthi

4、ghwaytotheepicenterofWenehuanEaahquake．Thegeo—hazardslonganddamagetothehighwayarethemostserious．Thispaperpresentsacompre-hensiveinvestigationofthegeologicalhazardsduetotheea~hquakealongthehighway．Basedontheircharacteris—tics，thegeo—hazardsaredividedintofourtypes．Theyareinstabilityof

5、highlyweatheredrockmassandsoilontheupperpartoftheslopes，instabilityofrockmasscutbygeologicalstructuralsurface，landslidesanddebrisflows．Itanalyzesthedevelopmentallawofgeo—hazardsalongthehighway．Thegeo—hazardsshowsignificantdeviationsbe—tweenthetwosidesofthebackrangefaultsattheLongmen

6、Mountainfaultzone．Thereasonsaretheseismicisola—tionefectofthedeepfracture，scalingefectofthelandforms，andgeologicstructures．Theslopesteepnessandpo—sitionofseismicinstabilitieshavebeenstudiedviatheanalysisof134geologicalsections．Theresultsshowthattheslopesteepnessofseismicinstabilitie

7、saredistributedwithintherangeoffrom33。to84。．mainlyfrom40。to65。．So，itcanbeconcludedthatthegeo—hazardscausedbytheearthquakemainlytookplaceontheroadslopessteeperthan40。．Thefailurezonescausedbyseismicforcemainlydistributedontheupsideoftheroadslopes．Theinsta—bilitypositionsaremainlyupont

8、hepaaswithslopegrad