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1、第32卷第8期岩土力学Vol.32No.82011年8月RockandSoilMechanicsAug.2011文章编号:1000-7598(2011)08-2353-06非贯通类节理岩体剪切变形规律分析1,21,23唐志成,夏才初,丁增志(1.同济大学岩土及地下工程教育部重点实验室,上海200092;2.同济大学地下建筑与工程系,上海200092;3.中国中铁二院集团有限责任公司,成都610031)摘要:通过直剪条件下的模型试验研究具有相同连通率、含不同起伏角的共面闭合节理在不同法向应力作用下的剪切变形特征。试验结果表明:在达到峰值剪切强度前,剪切应力-位移曲
2、线具有明显的线性段与非线性段;岩桥在法向与剪切荷载的共同作用下会产生一定程度的弱化,积累到一定程度时宏观表现为剪切应力软化。详细阐述了试验过程中裂纹发展的4个阶段并描述了剪切应力-剪切变形曲线变化的特征,提出一个能反映剪切应力-剪切变形曲线全过程的经验本构模型。新模型采用分段函数描述曲线变化特征。直剪试验数据分析表明,该模型能够拟合剪切应力-剪切变形变化发展趋势且具有较高的拟合精度,验证了模型的正确性。最后,对其存在的不足亦进行了简要分析。关键词:岩石力学;非贯通节理;模型试验;裂纹扩展;应力-变形关系中图分类号:TU452文献标识码:AAnalysisofsh
3、eardeformationlawforintermittentjointedrockmass1,21,23TANGZhi-cheng,XIACai-chu,DINGZeng-zhi(1.KeyLaboratoryofGeotechnicalandUndergroundEngineeringofMinistryofEducation,TongjiUniversity,Shanghai200092,China;2.DepartmentofGeotechnicalEngineering,TongjiUniversity,Shanghai200092,China;3.
4、ChinaRailwayEryuanEngineeringGroupCo.,Ltd.,Chengdu610031,China)Abstract:Throughmodeltestsunderdirectshearcondition,thesheardeformationofrockcontainingcoplanarclosejointswiththesamecontinuityanddifferentundulatinganglesarestudiedunderdifferentnormalstresses.Directsheartestsshowthatbef
5、orepeakshearstrength,theshearstress-displacementcurveofintermittentjointhaslinearandnonlinearsegments;therockbridgeproducessomedegreeofweakeningundernormalandshearloads;andshowsmacroscopicshearstresssofteningwhenaccumulatedtosomedegree.Thefourstagesofcrackdevelopmentandcharacteristic
6、sofshearstress-deformationcurvearedescribedindetail;andanempiricalconstitutivemodelissuggestedwhichcanfitthewholeprocessofshearstress-sheardeformationcurve.Piecewisefunctionisusedtodescribecurvecharacteristic.Dataanalysesshowthatthemodelcanfittheshearstress-sheardeformationtrendsandh
7、asahighfittingaccuracywhichverifiesthecorrectnessofthisnewmodel;finally,itsinadequacyisalsogivenbriefly.Keywords:rockmechanics;intermittentjoint;modeltest;crackdevelopment;stress-deformationrelation形是接触微凸体的压碎、张裂,提出类似广义Hook1引言定律的弹性本构关系。采用双曲线函数描述节理峰工程节理岩体通常由贯通节理岩体与非贯通值前剪切应力-位移的非线性关系,但没
8、有讨论峰值节理岩体组成,