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时间:2020-03-23
《人工降雨条件下冲沟型泥石流起动试验研究.pdf》由会员上传分享,免费在线阅读,更多相关内容在行业资料-天天文库。
1、JournalofEngineeringGeology工程地质学报1004-9665/2015/23(1)011108DOI:10.13544/j.cnki.jeg.2015.01.016人工降雨条件下冲沟型泥石流起动试验研究倪化勇(成都地质矿产研究所成都610081)摘要下垫面以位于贡嘎山东坡的熊家沟为模型,开展了不同降雨强度条件下冲沟型泥石流起动的模拟试验,初步研究了冲沟型泥石流的形成机理和演化特征。试验研究表明:(1)在强降雨条件下,水体入渗速度、不同深度土体含水量变化与降雨强度呈反比例关系,降雨强度越大,越不利于水体入渗,而有利于坡面汇流、冲沟径流和下切侵蚀;(2)在
2、强降雨和径流条件下,土体破坏方式、破坏程度以及泥石流形成机理表现出差异性。相对较小雨强降雨条件下,土体破坏方式以滑坡为主,泥石流形成模式表现为滑坡液化与转化起动,雨强较大降雨条件下,土体破坏方式以侵蚀垮塌为主,泥石流形成模式为洪流席卷垮塌体和沟床揭底;(3)起动试验中泥石流阵性特征明显。在强降雨条件下,雨强与泥石流的规模、黏度之间没有正相关性,雨强越大,泥石流黏度越小,试验中多出现的是高含砂洪流,而相对较小雨强作用下由土体液化转化形成的泥石流黏度较大。试验现象和结果与熊家沟泥石流起动、发生过程具有较高的一致性。关键词冲沟型泥石流人工降雨模拟试验雨强形成机理熊家沟中图分类号:P642
3、23文献标识码:AFIELDEXPERIMENTSFORGROOVETYPEDEBRISFLOWINITIATIONWITHARTIFICIALRAINFALLNIHuayong(ChengduInstituteofGeologyandMineralResources,ChinaGeologicalSurvey,Chengdu610081)AbstractDebrisflowscanoccurabruptlyandrapidlyinmountainousareas.Itisdifficulttoobservetheiroccurrenceprocess.Therefore,fi
4、eldexperimentbecomesanimportantmethodtostudydebrisflowinitiationmechanisminrecentyears.ThispapertakesXiongjiagullyasanexampleandusesartificialrainfallexperimenttostudyinitiationofgroovetypedebrisflow.Experimentalresultsindicatesomerelationsamongrainfallintensityandgullyerosion,slopestabilitya
5、ndfailuremode,debrisflowinitiationmechanismandcharacteristics.Conclusionsaredrawnasfollows:(1)Understrongprecipitation,infiltrationrateandsoilwatercontentatdifferentdepthsareinverselyproportionalwithrainfallintensity.Intenserainfallfavorsoverlandflow,gullyrunoffanderosion,butisnotconducivetowa
6、terinfiltration.(2)Slopefailuremodesanddebrisflowinitiationmechanismarevariousunder-1differentrainfallandrunoffconditions.Undertheconditionwithrainfallintensityof55mm·h,theslopefailuremodepresentssoilliquefactionandlandslide.Accordingly,debrisflowinitiationmechanismbelongstolandslideconversion
7、.However,undertheconditionofintenserainfallandrunoff,gullybedsareeasilytobeerodedandslopesarepronetocollapse.Then,debrisflowsoccurredwithinitiationmechanismofentrainment.(3)Intermsof收稿日期:2014-01-02;收到修改稿日期:2014-05-28.基金项目:国家自然科学基金项目(41
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