非线性硬化与软化的巷道围岩应力分布与工况研究

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1、第25卷第7期岩石力学与工程学报Vol.25No.72006年7月ChineseJournalofRockMechanicsandEngineeringJuly2006非线性硬化与软化的非线性硬化与软化的巷道非线性硬化与软化的巷道巷道围岩巷道围岩围岩应力分布围岩应力分布应力分布与应力分布与与工况研究与工况研究潘岳王志强王在泉(青岛理工大学土木工程学院山东青岛266520)摘要采用摄动法得到接近岩体实际的弹性应变非线性硬化和软化3段光滑连接的本构模型求得静水压力下圆形巷(隧)道围岩塑性硬化区和软化区的应

2、力分布规律给出围岩平衡方程地应力–硐室位移关系和围岩特征方程分析中可自然导出围岩自承地应力上限概念根据围岩平衡方程写出围岩弹性区硬化区和软化区分担地应力的表达式计算表明围岩硬化区承载力p大于弹性区承载力p软化区也有相当的承载能力特别是所求得的he切向应力s/p-r/a曲线光滑连接没有尖峰向上的应力集中此结果与其他学者在巷(隧)道模拟试验中测得的s-rq0q曲线形状一致从理论上证明基于理想弹塑性本构模型的Kastener解在围岩软化区半径处的s-r曲线有尖峰向上q的应力集中与实际不符关键词岩石力学巷道非

3、线性硬化非线性软化应力分布规律围岩平衡方程围岩特征方程中图分类号TU45文献标识码A文章编号1000–6915(2006)07–1343–09STUDYONSTRESSDISTRIBUTIONOFSURROUNDINGROCKANDWORKCONDITIONOFTUNNELBASEDONSTRAINNONLINEARHARDENINGANDSOFTENINGPANYueWANGZhiqiangWANGZaiquan(InstituteofCivilEngineeringQingdaoTechnolog

4、icalUniversityQingdaoShandong266520China)AbstractAconstitutivemodelwhichcanalmostdescribethecharacteristicsofrockmasstrulyisobtainedbyperturbationmethod.Thecurveoftheconstitutivemodelislinkedglossilybyelasticstrainnonlinearhardeningandnonlinearsoftening

5、segments.Thestressdistributionlawsinplastichardeningandsofteningzonesofsurroundingrockunderhydrostaticpressureareachieved.Basedontheanalysesequilibriumequationofsurroundingrockrelationshipbetweengeostressandtunneldisplacementandcharacteristicequationofs

6、urroundingrockarepresentedandtheexpressionsofgeostresssharedbyelasticzonehardeningzoneandsofteningzoneofsurroundingrocksaregiven.Calculationshowsthatthebearingcapacityofthehardeningzoneofsurroundingrockismorelargethanthatofelasticzone.Especiallythecurve

7、ofsq/po-r/ahasnoup-pinnacledstressconcentrationandtheresultaccordswellwiththeexperimentoneofotherscholar.ItispointedoutthatthereareobviouslimitationsinKastenerformulawhichisbasedonidealelastoplasticconstitutivemodelandtheup-pinnacledstressconcentrationo

8、fsq-rcurvedoesnotcorrespondwiththepracticalone.Keywordsrockmechanicstunnelnonlinearhardeningnonlinearsofteningstressdistributionlawequilibriumequationofsurroundingrockcharacteristicequationofsurroundingrock收稿日期2005–02–01修回日期2005–