岩土破损力学_结构块破损机制与二元介质模型

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1、文章编号：1000－7598(2010)增刊1－0013－11岩土破损力学：结构块破损机制与二元介质模型刘恩龙（四川大学水利水电学院，成都610065）摘要：沈珠江等在总结岩土材料的基本特性、分析理论和研究方法的基础上，提出了岩土破损力学理论框架和二元介质模型概念。基于岩土二元介质模型思想，近年来在试验、理论和数值模拟方面对结构性岩土材料进行了详细研究。通过对棒状和棱柱状结构块试件的平面试验，探讨了结构性岩土材料的破损机制，并发现了在受荷过程中结构块逐渐破损并转化为软弱带二者共同抵抗外部作用，即验证了二元介质模型对结构性岩土材料力学抽象的正确性；扩展了岩土二元介质模型对岩土材料的脆

2、性变化进行了模拟，并与结构性土和砂岩的三轴试验结果进行了验证；基于二元介质模型概念，发展了一种模拟岩土材料破损过程的细观数值方法，同时提出了适用于结构性岩土材料的强度准则。关键词：二元介质模型；破损力学；结构块；结构性土；试验；细观数值分析；强度准则中图分类号：TU43文献标识码：ABreakagemechanicsforgeomaterials:Breakagemechanismofstructuralblocksandbinary-mediummodelLIUEn-long(SchoolofHydraulicandHydropowerEngineering,SichuanUni

3、versity,Chengdu610065,China)Abstract:Basedontheanalysisofthemechanicalfeaturesandfundamentaltheoryofgeologicalmaterials,Shenetal.(2002and2003)proposedtheframeworkofbreakagemechanicsforgeomaterialsandtheconceptofbinary-mediummodel(BMM).Recently,wehavecarriedoutmuchresearch,includingtests,theory

4、andnumericalsimulation,onthestructuredgeomaterialsonthebasisofthebinary-mediummodelconcept.Planetestsofthesamplesassembledbygeo-structuralblockswereconductedtoinvestigatethebreakagemechanismofstructuredgeomaterials.Itwasexperimentallyfoundthatthestructuralblockswillgraduallybreakandtransformto

5、theweakeningbands;andbothofthemwillbeartheloadingtogetherduringtheloading,testifyingmechanicalidealizationofbreakagemechanicsforstructuredgeomaterials.Anewmethodofpreparingforstructuredsoilswasexplored;andthemechanicalandstrengthcharacteristicsofartificiallypreparedstructuredsoilswerestudiedun

6、derdifferentstresspaths.Thebinary-mediummodelforgeomaterialswasextendedandverifiedthatitcouldbeusedtosimulatethebrittlenesschangeofgeomaterialsandexperimentalresultsofstructuredsoilsandsandstonesundertriaxialstressconditionswell.Basedontheconceptofthebinary-mediummodelforgeomaterials,amesoscop

7、icnumericalmethodwhichcansimulatethebreakageprocessesofgeomaterialswasproposed;andastrengthcriterionforstructuredsoilswasputforwardfinally.Keywords:binary-mediummodel(BMM);breakagemechanics;structuralblocks;structuredsoils;tests;mesosco