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1、第31卷第11期岩土力学Vol.31No.112010年11月RockandSoilMechanicsNov.2010文章编号:1000-7598(2010)11-3441-07水压和应力耦合下脆性岩石蠕变与破坏时效机制研究1,2111黄书岭,冯夏庭,周辉,张传庆(1.中国科学院武汉岩土力学研究所岩土力学与工程国家重点实验室,武汉430071;2.长江科学院水利部岩土力学与工程重点实验室,武汉430010)摘要:基于水压和应力耦合作用下锦屏深部大理岩的三轴蠕变试验,研究了大理岩的变形时效特性、等时曲线特征以及时效破坏机制。研究结果表明,(1)孔隙水压可以增强大理岩的时效变形能力,有
2、水压时的稳态蠕变率大于无水压状态时的稳态蠕变率。(2)裂纹扩容失稳应力强度比可以作为硬脆性岩石是否发生失稳蠕变的门限值,且当应力强度比到达这一门限值时,岩石的失稳概率随着时间发展而陡增。(3)体积蠕变量大于侧向和轴向的蠕变量值,显示脆性岩石扩容蠕变效应特征显著。(4)不同时刻的等时曲线具有明显的相似性,在发生加速蠕变之前,等时曲线基本呈线性特征;而在发生加速蠕变时,等时曲线呈显著非线性特征。关键词:应力和水压耦合;硬脆性岩石;三轴蠕变试验;变形破坏时效机制中图分类号:TU452文献标识码:AStudyofagingfailuremechanicsandtriaxialcompres
3、sioncreepexperimentswithwaterpressurecoupledstressofbrittlerock1,2111HUANGShu-ling,FENGXia-ting,ZHOUHui,ZHANGChuan-qing(1.StateKeyLaboratoryofGeomechanicsandGeotechnicalEngineering,InstituteofRockandSoilMechanics,ChineseAcademyofSciences,Wuhan430071,China;2.KeyLaboratoryofGeotechnicalMechanics
4、andEngineeringofMinistryofWaterResources,YangtzeRiverScientificResearchInstitute,Wuhan430010,China)Abstract:BasedontriaxialcompressionrheologicalexperimentswithwaterpressurecoupledstressabouttheJinpingmarblefromthedeepsiteinJinpingIIdiversiontunnel,theagingdeformationcharacteristics,isochronou
5、scurveandagingfailuremechanicsarediscussedindetail.Thetestresultsshowthat:(1)Waterpressurecanenhancetheagingdeformationcapacityofthemarble,andthesteady-statecreeprateunderwaterpressureisgreaterthanthatwhenthereisnotwaterpressure.(2)Stressstrengthratioofcrackdilateinstabilitycanbeusedascreepins
6、tabilitythresholdofbrittlerock,andwhenstressstrengthratioreachedthisthreshold,theprobabilityofrockinstabilityincreasedsharplywithtimetodevelop.(3)Volumecreepvalueisgreaterthanthelateraloraxialcreepvalue,whichindicatesthatthereisadistinguishingdilatecreepfeatureofbrittlerock.(4)Isochronouscurve
7、sofbrittlerockatdifferenttimehaveobvioussimilarities,andacceleratingcreepago,thecurvesarelinear,butintheeventofaccelerationcreep,thecurvesaresignificantlynon-linearcharacteristics.Keywords:waterpressurecoupledstress;brittlerock;triaxial