小湾水电站坝址区低高程岸坡表生改造特征及机制研究.pdf

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1、JournalofEngineeringGeology工程地质学报1004—9665／0000／17(6)-0802-07小湾水电站坝址区低高程岸坡表生改造特征及机制研究林锋黄润秋裴钻吴琦高政(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)摘要小湾水电站坝基、水垫塘边坡及低高程排水洞系统广泛地揭示了低高程岸坡的地质特征。基于现场调查和二维弹塑性有限元分析，深化认识了低高程岸坡表生改造特征：(1)它是在建造和构造改造的基础上进行的：原构造缓倾角节理扩展、错动；陡倾角节理扩展、产状

2、改变以及错动；新生了大量中缓倾角裂隙；表生改造程度向坡内减弱。(2)建立了低高程岸坡表生改造缓裂生成机制模型，分析了其生成过程。(3)在二维弹塑性有限元分析中，基于拉破坏区分布、剪应变和点安全度等指标，分析了低高程岸坡卸荷松弛范围，其中谷底表生改造明显影响深度为6—9m。关键词小湾水电站低高程岸坡表生改造卸荷松弛弹塑性有限元中图分类号：TU457文献标识码：AEXoGENETICRECoNSTRUCTIONCHARACTERISTICSANDMECHA．NISMoFLoWERELEVATIoNBANK

3、SLoPEATDAMSITEoFXLoW．ANHYDRoPoWERSTATIoNLINFengHUANGRunqiuPEIZuanWUQiGAOZheng(StateKeyLaboratoryofC．eo—hazardPreventionandGeo—environmentProtectioninChengduUniversityofTechnology，Ch~ngdu6113059)AbstractThegeo——characteristicsofthelowerelevationbankslope

4、ofXiaowanHydrostationweresystematicallyandwidelyobservedatthefoundationofdam，theslopeofwater—cushionpondandlowerelevationdrainagegal—leries．Basedonfieldinvestigationand2Dfiniteelementanalysisofelasticityandplasticity。theexogeneticrecon-structioncharacte

5、risticsoflowerelevationbankslopeweremoreunderstood．(1)Itsdevelopmentwasbasedonthereconstructionofrockassociationandstructure，includingthestretchandslippageofoldgentlejoints。thestretchandslippageofdeepjointsandtheirchangingofoccurrence，thenewgenerationof

6、agreatnumberofmiddle—gen—tlecracks，theweakerandweakerexogeneticreconstructioninwards．(2)Thegenerationmechanismandmodelofgentlecrackstriggeringfromexogeneticreconstructioninlowerelevationwasestablished，andtheformationprocesswasanalysed．(3)Duringthe2Dfini

7、teelementanalysisofelasticityandplasticity，theslackboundaryduetoan—loadinginlowerelevationwasstudiedonthebasisoftheindexesoftensilelydestroyedzonedistribution，shearingstrainandpointsafetydegree．Asaresult，theobviousdepthaffectedbyexogeneticreconstruction

8、onthebottomofvalleywouldreach6to9m．KeywordsXiaowanHydropowerStation，Bankslopeoflowerelevation，Exogeneticreconstruction，Unloadingrelaxation，Finiteelementofelasticityandplasticity收稿日期：2009—0l一09；收到修改稿日期：2009—02—18．第一作者简介：林锋，主要从事地质工