地震荷载作用下坝及其岩基脆性动力损伤分析

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1、第23卷第8期岩石力学与工程学报23(8)：1311～13172004年4月ChineseJournalofRockMechanicsandEngineeringApril，2004*地震荷载作用下坝及其岩基的脆性动力损伤分析张我华邱战洪余功栓(浙江大学岩土工程研究所杭州310027)摘要将损伤、渗流及孔隙率演化等相互耦合的有效应力概念引入Mohr-Coulomb破坏准则，对岩石类的脆性材料建立了一种动力损伤破坏的模型，并应用该模型对地震荷载作用下的坝和岩基的破坏过程进行了脆性动力损伤分析。这种方法从连续损伤力学的观点研究了岩体结构在动力荷载作用下脆性损伤-破坏的突变机

2、理。结果表明，损伤会在坝与岩基的上游坡的结合处由于应力集中而明显地增长。在硬岩基上的坝内，损伤发展比软岩基上灵敏。关键词岩石力学，岩石脆性损伤突变，损伤演化律，有限元动力分析，坝与岩基，地震响应分类号O346.5文献标识码A文章编号1000-6915(2004)08-1311-07ANALYSISOFBRITTLEDYNAMICDAMAGEINDAMANDROCKFOUNDATIONDUETOEARTHQUAKEZhangWohua，QiuZhanhong，YuGongshuan(GeotechnicalEngineeringInstitute，ZhejiangUniv

3、ersity，Hangzhou310027China)AbstractInthispaper，abrittledamage-failuremechanismforrockstructuressubjecttoearthquakeloadingisadoptedforanalysisofdynamicresponsesofdamagedconcretegravitydamsandrockfoundation.Theconceptofthemodifiedneteffectivestresswhichinvolvesthecouplingaffectsamongdamage

4、，porepressureandporosityevolutionincrackedrockmassandconcreteisintroducedintothemodifiedMohr-Coulombfailurecriterioninordertoexpressthebrittledynamicdamagegrowthandpropagationphenomenon.Thedevelopedbrittledynamicdamagemodelisbasedonthelocalizationofdamagedfailureinbrittlematerials.Theref

5、ore，thebrittledynamicdamageprocessisconsideredastheprocessoflocalfracturesinmaterialwithoutplasticdeformations.Thedissipationsofenergyduringthedynamicprocessconsistofdissipationsofthelocaldamagedevelopment，thelocalchangesofseepageflowvelocityandthelocalevolutionofporositywithinthenetwork

6、sofcrack-damagedporosityonly;noenergyisdissipatedwiththeeverlastingdeformation.Thenumericalresultsofthebrittledynamicdamageanalysisfortheconcretedamandtherockfoundationshowthatthesignificantdamagegrowthstartsintheupstreamsideatthecornerbetweenthedamandrockfoundationwhereahighstressconcen

7、trationareaexists.Damagegrowthisfoundtobemoresusceptibleinthesofterrockfoundationthanthatintheintactrockfoundation.Keywordsrockmechanics，localizationofbrittlefracture-damage，damageevolution，dynamicfiniteelementanalysis，damandrockfoundation，earthquakeresponse2002年11月22日收到初