软弱基座型斜坡变形破坏机制模拟研究.pdf

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1、JournalofEngineeringGeology工程地质学报1004—9665／2014／22(3)一0421—07DOI：10．13544／j．cnki．jeg．2014．03．010软弱基座型斜坡变形破坏机制模拟研究术兰志勇赵建军翟崇李俊杰龚凌枫(地质灾害防治与地质环境保护国家重点实验室(成都理工大学)成都610059)摘要软弱基座型斜坡崩滑在我国西南山区及三峡库区是一种较为常见的地质灾害。下伏软岩在上部硬岩重力作用和外营力地质作用下产生压缩变形，向临空方向塑性流动，导致上部硬岩拉裂，进一步发展演变为崩滑。贵州某斜坡为一典型缓倾内软弱基座斜坡，上部为灰岩形成高

2、度约150m陡崖，下部为厚度大于150m泥岩形成的缓坡。调查发现上部硬岩坡肩部位产生多条深大拉裂，坡肩局部发生过多次崩塌落石现象，斜坡变形仍在继续。本文采用有限元数值模拟和底摩擦物理模拟相结合的方法，分析了该斜坡坡体内应力、变形分布特征和发展过程，在此基础上研究软弱基座型斜坡的变形破坏机制，为软弱基座斜坡崩滑地质灾害防治提供理论支撑。研究结果表明，缓倾内具软弱基座的斜坡变形破坏机制表现为压缩(塑流)一拉裂一剪断三段式滑坡。关键词软弱基座有限元分析底摩擦试验滑坡中图分类号：P315，P642．21，P642．22文献标识码：AFAILUREMECHANISMoFSLoPE

3、SWITHSoFTBASEFRoMNUMERICALSIMULATIoNLANZhiyongZHAOJianjunZHAIChongLIJunjieGONGLingfeng(SateKeyLaboratoryofGeohazardPreventionandGeoenvironmentProtection，ChengduUniversityofTechnology，Chengdu610059)AbstractCollapsesandlandslidesinslopeswithsoftbaseareverycommongeologicdisastersinsouthwest

4、ernmountainregionsandtheThreeGorgesreservoirareaofChina．Theyareharmfu1．Theupperhardrockweight，theweatheringandwatersofteningandtheunderlainbysoftrockbasecangeneratecompressionandhorizontalplasticflowtowardsthefreeface．Therefore，theupperhardrockcangeneratetensilecracks．Uhimatelytheyleadto

5、collapsesandlandslides．AslopeinGuizhouisexamined．Itsupperparthasaheightofabout150mandisalimestonecliffs．Itslowerparthasathicknessgreaterthan150mandisashalegentleslope．Itisatypicalslopeofagentlyinclinedrampwithintheweakbase．Thispaperusesthefiniteelementnumericalsimulationandbottomfriction

6、methodofcombiningphysicalsimulation．Itanalysestheslopeofthebodystress，deformationdistributionanddevelopmentprocess．Basedonthismodel，thepaperstudiestheweakbaseofslopeanditsdeformationandfailuremechanismsandprovidesthetheoreticalsupportfortheweakbaseslopeofgeologicaldisastersprotection．The

7、resultsshowthattheslopedeformationandfailuremechanismsdippingthebaseareofthethreeperformanceofacompressedplasticflow，tensioncrackandshear-cut．KeywordsSoftfoundation，Finiteelementanalysis，Bottomfrictiontest，Landslide}收稿日期：2014—03—04；收到修改稿日期：2014—05—12．基金项目：国家自然科学基金(4110219