甘肃永靖黑方台地区灌溉诱发型滑坡发育特征 及力学机制.pdf

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1、第32巷第6期地质通报Vol32．No．62013年6月GE0L0GICALBULLETINOFCHINAJu『1c，2013甘肃永靖黑方台地区灌溉诱发型滑坡发育特征及力学机制朱立峰，胡炜，贾俊，马建全。，毕俊擘，孙巧银ZHULi—feng，HUWei，JIAJun，MAJian—quan，BIJun—bo，SUNQiao—yin1国土资源部黄土地质灾害重点实验室／中国地质调查局西安地质调查中心，陕西西安710054；2西安科技大学．陕西西安71()I)541KeyLaboratory／brGeo～hazardinLoessArea,MLR／Xi"anCente

2、rofGeologicalSurvey,CGS，Xi"an710054，Shaanxi，China,2Xi)mUniversityScienceandTechnology,Xi"an710054，Shaanxi，China摘要：水是诱发黄土滑坡最为积极的因素，以灌溉诱发型滑坡尤为典型。基于野外水工环地质综合调查，对黑方台地区灌溉渗透诱发滑坡的发育特征进行总结。通过分析特定孕灾地质条件下滑坡发育特征的差异，认为黄土滑坡形成的力学机制以滑移～压致拉裂一剪断型和蠕滑一拉裂一滑移型为主，而黄土一基岩滑坡以滑移一压致一拉裂型为主。滑移一压致拉裂一剪断型黄土滑坡为原位溯源后

3、退扩展式．系灌溉水入渗后造成黄土饱和带厚度增大，不仅造成台缘周边地下水溢出带部位渗透压力增大，且抗剪强度显著弱化．从而在坡体自重作用下发生蠕滑剪切。锁固段突然破坏使滑坡快速启动，滑体冲击致早期饱水滑床产生液化，产生高位抛射．借助原始地形滑体加速运移形成高速远程运动。蠕滑一拉裂一滑移型黄土滑坡是黄土底部饱和带厚度较薄或灌溉入渗影响较小的地段．以后缘拉裂为主激发形成。渗灌溉水长期入渗造成下伏基岩顺倾泥岩层面软化泥化，从而在顺向坡段产生黄土一基岩层滑坡．该类滑坡以低速短程滑坡为主关键词：灌溉渗透：滑坡灾害；形成机制；启动；机理中图分类号：P64222文献标志码：A文章

4、编号：1671—2552(2013)06—0840—07ZhuLF，HuW，JiaJ，MaJQ，BiJB，SunQY。Developmentfeaturesandmechanicalmechanismofirrigation—inducedlandslidesinHeifangtai，GansuProvince．GeologicalBulletinofChina,2013，32(6)：840—846Abstract：Loessshowsintensivewatersensitivity，andhencewaterbecomestheIIlostpositivef

5、actortriggeringloesslandslides，ofwhichirrigation—inducedlandslidesaremosttypica1．Basedonfieldgeologicalsurvey，thispapersummarizedthedevelopmentfeaturesofirrigation——inducedlandslidesinHeifangtai．Accordingtoallanalysisofthedevelopmentconditionsanddevelopmentfeaturesofdigferm1ttypesofl

6、andslides．theauthorsholdthatthemechanicalmechanismsofloesslandslidesmainlyincludesliding—compression—in—ducedtensioncrack—snippingandcreep—tensioncrack—sliding．whilethemechanismforloess—bedrocklandslidesismainlysliding—compression-inducedtensioncrack—snippingLoesslandslidesstartwitht

7、heincreaseofthicknessofsaturatedloesslayerafterinfiltra—tionofirrigad0nwaterThewatercontentofunsaturatedloessdifersfromthatofsaturatedloess，andthereforeshearstrengthofloessisweakened．Furthermore，theincreaseofgroundwatertableduetolong—teriwtirrigationleadstotheincreaseoftheseepageforc

8、eattheedgeof