几种岩石强度准则的对比分析

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1、第32卷增刊1岩土力学Vol.32Supp.12011年4月RockandSoilMechanicsApr.2011文章编号：1000－7598(2011)增刊1－0209－08几种岩石强度准则的对比分析石祥超，孟英峰，李皋（西南石油大学油气藏地质及开发工程国家重点实验室，成都610500）摘要：采用常规三轴试验数据，以最小平均拟合差为评价指标定量地对比分析5种强度准则描述岩石非线性强度特征的适用性。结果表明：直线型Mohr-Coulomb准则不能描述岩石强度的非线性特征；抛物线型Mohr-Coulomb虽能描述岩石强度的非线性特征，但拟合误差较大，计算所得强度参数与

2、事实不符，不宜使用；对于中低围压（σ<σ）下岩石强度的非线3c性特征，单参数Bieniawski准则拟合精度与Hoek-Brown准则相当或稍好，拟合精度接近于指数强度准则，均优于双参数Bieniawski准则；在高围压下岩石强度非线性特征较为显著，应用单参数Bieniawski准则或Hoek-Brown准则描述误差较大，三参数Bieniawski准则和指数强度准则拟合误差较小，可用于评价深部或特深部高应力状态下岩石的强度特征。关键词：岩石强度准则；岩石非线性强度特征；强度准则适用性；最小平均标准拟合差中图分类号：TU452文献标识码：AComparativeanal

3、ysesofseveralrockstrengthcriteriaSHIXiang-chao,MENGYing-feng,LIGao（StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,SouthwestPetroleumUniversity,Chengdu610500,China）Abstract：Leastmeanstandardfittingdeviationisusedasanevaluationindex;weanalyzetheapplicabilityoffiveconventiona

4、ltriaxialstrengthcriteriatodescribethenonlinearstrengthcharacteristicsofrocksbasedontestdataoftenrockscitedfrompublicliteratures.ItisobviousthatlinearMohr-Coulombcriterioncan’tdescribethenonlinearstrengthcharacteristicsofrocks.ParabolicMohr-Coulombcriterioncandescribethenonlinearityfeat

5、ureofrockstrength;butforthereasonthatthefittingerrorisverygreatandtheparametersfromcalculationisnotconsistentwiththerealdata;soitisnotsuitabletoapplyparabolicMohr-Coulombcriterioningeotechnicalengineering.Forthenonlinearstrengthcharacteristicsofrocksatlow-to-moderateconfiningpressurelev

6、el（σ<σ）,theBieniawskicriterionwithasingleparameterandHoek-BrownCriterionisbetterthanBieniawskiCriterionwithtwo3cparameters;theirfittingaccuracyisclosetoexponentialstrengthcriterionwiththreeparameters;buttheycan’tbeusedathighconfininglevel.Whennonlinearstrengthcharacteristicsareverysigni

7、ficantunderhighconfiningpressure,thefittingdeviationsofBieniawskicriterionwiththreeparametersandexponentialstrengthcriterionwiththreeparametersaresmaller;sotheycanbeusedtoevaluatethestrengthunderhighgeostress.Keywords:strengthcriterionofrocks;nonlinearstrengthcharacteristicsofr