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1、JournalofEngineeringGeology工程地質學報1004—9665/2010/18(6)-0862—05川藏公路茶樹山滑坡特征及成因機制分析白永健①鄭萬模①李明輝①易志堅②王東輝①(①中國地質調查局成都地質調查中心成都610081)(②成都理工大學地質災害防治與地質環(huán)境保護國家重點實驗室成都610059)摘要通過對川藏公路茶樹山滑坡地質環(huán)境條件的系統(tǒng)調查研究,分析了滑坡巖土體結構、邊界條件、變形特征、影響因素,并結合3DEC數值模擬,對其變形破壞機制進行了深入的探討。綜合分析表明,滑坡位于活動斷裂帶內,后緣斜坡陡峭,巖體破碎,同時前緣為較厚的松散堆積體
2、斜坡,在地震活動、降雨等影響因素的誘發(fā)作用下,滑坡成因機制主要表現為以下3個階段:(1)傾倒拉裂階段,滑坡受后緣地形及巖體結構控制作用較為明顯,在坡體淺表層一定深度范圍內出現較為強烈的傾倒拉裂變形帶,產生傾倒.拉裂滑動;(2)蠕滑變形階段,前緣松散堆積體在強大的自重推力作用下發(fā)生蠕滑變形;(3)前部“鎖骨段”剪斷,整體失穩(wěn)階段,滑坡前部鎖骨段在自重推力及斷層活動的持續(xù)影響下,發(fā)生剪斷,控制后緣傾倒拉裂體穩(wěn)定性的潛在滑面與前緣松散堆積體體內的剪切滑動面貫通,滑坡整體失穩(wěn)。關鍵詞反傾滑坡活動斷裂成因機制傾倒拉裂一蠕滑3DEC中圖分類號:TU457文獻標識碼:ACHARACT
3、EISTICSANDFoRMATIoNMECHANISMoFCHA.SHU.SHANLANDSLIDEoNSICHUAN.TIBETHIGHWAYBAIYongjian①ZHENGWanmo①LIMinghui①YIZhijian②WANGDonghui①(①ChengduCenterofChinaGelo~calSurvey,Chengdu610081)((~StationKeyLaboratoryofC.eo—hazardPr~entionandGeo—EnvironmentProtection,Chengdu610059)AbstractBasedonthesys
4、tematicinvestigationofcha—shu—shanlandslideonChuan—Zanghighway,thispaperall—alyzesthelandslide’rockandsoilstructures,boundaryconditions,deformationcharacteristics,influencefactorsandformationmechanism,andmakesain-depthdiscussionscombinedwith3DECnumericalsimulation.Thecompre—hensiveanalys
5、isshowsthatthelandslideislocatedinanactivefault.Thebackedgerockispoor,andthefrontlooseaccumulationisthick.Underseismicactivity,rainfallandotherfactorseliciting,thefailuremechanismoflandslidecanbedividedintothefollowing3stages:(1)stageoftopplingandpul—splitting,thebackedgeland—slidesstabi
6、ltyiscontroledbythetopographyandstructureofrockmass,whereformesaratherstrongdumpedrup—turedeformationbelt.Thengeneratesslippage.(2)stageofcreepdeformation,thefrontlooseaccumulationbodyoccurscreepdeformationinapowerfulgravitythrust.(3)stageoffailing,claviclesegmentareeuttedintheweightthru
7、standthecontinuingeffectsoffaultactivity。Thenthebackedgepotentialslideplaneandfrontshearslipplanearelinkedthewholelandslidefails.KeywordsCounter—inclinedslope,Activefault,Formationmechanism,Toppling—pullsplitting—creep,3DEC$收稿日期:2009—12—12;收到修改稿日期:2010一叭一04.基金項目:地調項目:中國地質