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1、鄧肯模型參數(shù)k、n、Rf整理方法研究張波(西女地質礦產勘查開發(fā)院,陜西,西女710100.)摘要:對四種石渣料進行三軸CD試驗,采用全部法(全部試驗點)、70?95法(應力水平70?95%的試驗點)及分段法(小應變試驗點求參數(shù)k、n,應力水平70?95%的試驗點求參數(shù)Rf)三種方法來求取Duncan-Chang模型參數(shù)k、n、Rf,并采用三種方法求取的參數(shù)擬合應變應變Illi線與試驗Illi線對比,研究了不同求取方法的優(yōu)劣。結果表明:三軸試驗應力應變Illi線并不完全符合雙Illi線關系,引/(W6)?引關系Illi線表現(xiàn)出明顯的雙線性,轉折點應變約為1%;石渣料址然是無粘性土,但其粘聚力并
2、不為零,在工程中應予適當考慮;全部法和70?95法求収的參數(shù)擬介曲線與試驗曲線較為吻介,擬介效果較好,但考慮到應力應變軟化問題,70?95法求取的參數(shù)能較好的模擬試驗曲線,分段法求取的參數(shù)雖然符合物理力學意義,但由于求取參數(shù)k、n僅采用小應變的試驗點,擬合曲線與試驗曲線差別較人,建議采用應力水平70?95%的試驗點求MXDuncan-Chang模型參數(shù)k、n、Rfo關鍵詞:三軸試驗;石渣料;Duncan-Chang模型;應力■應變Duncanmodelparametersk,n,Rfsortingmethod/Zhang"o/Xi'anInstituteofGeologicalAndMine
3、ralexploration,Xi^anShannxi710100,China)Abstract:ThefourkindsofgravelmaterialfortriaxialCDtests,usingallmethods(alltestpoints),70-95method(stresslevel70?95%oftestpoints)andsectionmethod(smallstraintestpointdemandparameterk,n,thestresslevelof70to95%ofthetestpointsrequestparameterRf)arcthreewaystostr
4、ikeaDuncan-Changmodelparametersk,n,R弋andtheuseofthreemethodsofparameterfittingtostrikeastrain?straincurvesandtestcurvescomparativestudyoftheprosandconsofdifferentmethodstostrikc.Thcresultsshowedthat:Triaxialstress-straincurvedocsnotfiillycomplywiththehyperbolicrelationship,el/(al-a3)?£1curveshoweda
5、clearbilinear,theturningpointisabout1%strain;carbidematerialalthoughnoviscoussoil,butitscohesionisnotzero,theprojectshouldbeproperlytakenintoaccount;alllawandtostrikethelawfrom70to95parameterfittingcurveismoreconsistcntwiththeexperimentalcurve,fitbetter,butconsideringthestressstrain-softeningproble
6、ms,70to95lawparameterscanstrikeabettersimulationcurve,althoughtheparametersofsub-strikelawinlinewiththephysicalandmcchanicalsense,buttostrikeaparameterk,nusingonlyasmallstrainoftestpoints,theproposedcurvetogetherwiththeexperimentalcurvesvarygreatly,thestresslevelisrccommcnded70to95%ofthetestpointst
7、ostrikeDuncan-Changmodelparametersk,n,Rf.Keywords:triaxialtests;carbidematerial;Duncan-Changmodel;stress-strain土的本構模型研究是0前巖土工程的重要課題Z—,0前主要有非線性彈性模型及彈塑性模型⑴。前者中的Duncan-Chang模型⑵是基于Kondne?應力應變符合雙曲線的假定下建立的,以廣義虎克定