松散堆积体工程边坡变形机理分析及支护对策研究.pdf

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1、JournalofEngineeringGeology工程地质学报1004—9665／2008／16(5)-0611-05松散堆积体工程边坡变形机理分析及支护对策研究赵建军巨能攀涂国祥(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)摘要合理选择开挖坡比、正确认识变形破坏机理是影响松散堆积体边坡稳定性和施工安全的前提，本文研究了西南地区某松散堆积体工程边坡的结构特征，根据地形条件确定了合理的开挖坡比，采用二维有限元研究了开挖边坡的变形机理并根据模拟结果确定潜在滑动面，在此基础上，提出支护对策。研究结果表明，边坡由厚度达70m的

2、坡洪积、泥石流块碎石堆积体组成，斜坡下部缓中部稍陡，开挖平台位于缓坡部位，根据地形条件结合坡体结构特征确定边坡开挖坡比为1：0．75；数值模拟结果表明，边坡变形开挖面附近及坡顶拉应力和坡体下部最大剪应力控制，坡顶部位将首先产生拉张裂隙，开挖边坡内部产生从坡脚部位向上发展的剪切变形，滑面一旦与坡顶拉裂缝贯通，边坡将产生整体失稳；边坡采用锚拉桩、锚索框架、锚杆框架、排水相结合的综合治理措施进行支护。关键词松散堆积体边坡变形机理支护设计中图分类号：TD824．7文献标识码：ADEFoRMATIoNMECHANISMANDSUPPoRTINGMEASURE

3、SoFMANMADESLoPESINLooSEDEPoSITSZHAOJianjnnJUNengpanTUGuoxiang(StateKeyLaboratoryofGeohazardPreventionandGeo—EnvironmentProtection，ChengduUniversityofTechnology，Chengdu610059)AbstractThispaperistostudytheselectionofrationalsloperatioandslopedeformationmechanisminloosede-posits。

4、whichisthebasisofslopestabilityevaluationandsupportingdesign．Aman—madeslopecomprisingloosedepositsinSouthwestChinaistakenasanexample．Basedonstudyonthecharacteristicsofloosedeposits，rationalsloDeratioisdefinedaccordingtotheterrain．Two—dimensionalfiniteelementmethodisusedtostudy

5、deformationmechanismofthecutslopeandtodeterminepotentialslidesurface．Atlast，thesupportingmeasuresareputfor—wardaccordingtotheslopestabilityanalysis．Theslopehasloosedepositsof70minthicknesscomprisingalluvial，proluvial，anddebrisflowdeposits．Thesloperatioisdesignedas1：0．75because

6、theengineeringflatislocatedatthelowerpartoftheslowslope，whoseupperpartissteeper．Theresultofnumericalsimulationindicate~thatthecutslopeareaandtheslopecrestareageneratetensionstresses．Themaximumshearstressconcentratesatthelow—erpartoftheslope，whichresultintensioncracksattheslope

7、topandshearingdeformationatlowerpartoftheslope．Whentheshearingdeformationdevelopsupwardstothetensioncracks，theslopewouldshowanoverallin—stability．Accordingtothemechanismanalysisandresultofslopestabilityevaluation，asyntheticalsupportingmeasureisputforwardtoconformthestabilityof

8、theslopeduringexcavationandoperationperiods．Themeasureinclude