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时间:2019-05-11
《应力水平对结构性软黏土静力和动力变形特性影响的试验研究》由会员上传分享,免费在线阅读,更多相关内容在学术论文-天天文库。
1、第25卷第5期岩石力学与工程学报Vol.25No.52006年5月ChineseJournalofRockMechanicsandEngineeringMay,2006应力水平对结构性软黏土静力和动力变形特性影响的试验研究陈云敏,陈颖平,黄博(浙江大学岩土工程研究所,浙江杭州310027)摘要:采用原状和重塑软黏土样进行测量剪切波速的压缩试验及循环三轴试验,结果表明:在静荷载作用下,原状软黏土的变形特性随应力水平变化均可分为3个阶段,这3个阶段以先期固结应力和结构屈服应力为分界点,利用剪切波速可简单、方便地
2、判定出这2个关键应力值;重塑软黏土的变形规律与应力水平无关。对土体施加循环荷载时,两种土在不同固结应力下的应变–振次关系曲线上均存在着一个转折点,施加的动应力幅值不同,转折点应变也不相同,但该应变与相应的破坏振次呈线性关系。对于原状软黏土样,其转折点应变–破坏振次关系分3个阶段变化,且与压缩试验的3个阶段具有良好的对应关系;对于重塑软黏土样,其线性关系基本不随应力水平变化而变化;当原状土结构破坏后,两种土样的变形规律趋于一致。关键词:土力学;结构性软黏土;应力水平;剪切波速;循环荷载;应变中图分类号:TU4
3、3文献标识码:A文章编号:1000–6915(2006)05–0937–09EXPERIMENTALSTUDYONINFLUENCESOFSTATICANDCYCLICDEFORMATIONSONSTRUCTURALSOFTCLAYWITHSTRESSLEVELCHENYunmin,CHENYingping,HUANGBo(InstituteofGeotechnicalEngineering,ZhejiangUniversity,Hangzhou,Zhejiang310027,China)Abstract:
4、Thispaperpresentstheresultsofanexperimentalinvestigationperformedtostudytheinfluencesofstaticandcyclicdeformationsonundisturbedandremoldedsoftclaysampling.Thetestsindicatethatthedeformationofundisturbedsoftclaychangingwithstresslevelcouldbedividedintothree
5、stages.Thepreconsolidationandstructuralyieldingstressarethecut-offpointofthesethreestagesandtheycouldbedeterminedbyshearwavevelocitymeasurement.Thedeformationcharacteristicofremoldedclayisalmostindependentofstresslevel.Whencarryingoutcyclictriaxialtests,th
6、estraincurveswithcyclenumberofnaturalandremoldedsoftclayhaveallturningpointsunderdifferentamplitudesofstress.Beforetheturningpointsappear,thestraindevelopsslowlyandkeepstoasmalllevel.Butaftertheturningpointsappear,thestraindevelopsquicklyandbecomeslargefin
7、ally.Thestrainatturningpointschangedwithdifferentstressamplitudes,buttheyalmostfallonasamelineandcouldbefittedbyalinearequation.Thechangeoffittingparametersofnaturalsoftclaycouldalsobedividedintothreestageswhichcorrespondwelltoconsolidationtests.Andsimilar
8、ly,thefittingparametersofremoldedsoftclayalmostdidnotchangewithstresslevel.Thedeformationcharacteristicofthesetwokindsofsoftclaystendstobeconsistentwhenthestructureofnaturalsoftclayisdamaged.Keywords:soilmech
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