土动模量的退化和阻尼比变化
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摘要
针对双曲线关系不能很好地拟合土动模量随动力作用水平的退化,及Hard in和D rnevich的确定阻尼比的公式低估了动力作用水平低于一定值时的阻尼比的问题,基于3种黏性土动模量的试验结果,提出了一个能很好拟合动模量退化的数学关系,式中所包括的参数少且容易确定.研究了固结压力对动模量退化的不可忽视的影响,提出了一个确定阻尼比的改进公式.上述成果可以合理地确定动力分析中土的动模量和阻尼比,提高分析结果的可信性.
It is illustrated that hyperbolic relation can't satisfactorily fit degradation of dynamics moduli of soils with dynamic effect level.It is pointed out that Hardin and Drnevich's formula for determination of damping ratio underestimates damping ratio of soils when the dynamic effect level is lower than a certain value.Based on experimental data of dynamic moduli of three types of soils in Ying kou area,a mathematical relation which can satisfactorily fit the degradation of dynamics moduli is presented,and number of parameter in the relation is less than that in improved Hardin and Drnevich's hyperbolic relation and determination of the parameters is easy.Important influence of consolidation pressure on the degradation of dynamics moduli is studied and a method considering the influence is proposed.An improved formula to determine damping ratio which can satisfactorily fit the experiment data is presented.The dynamics moduli and damping ratio used in dynamics analysis of soil mass can be determined reasonably from mentioned results above,and reliability of the dynamics analysis results can be increased.
It is illustrated that hyperbolic relation can't satisfactorily fit degradation of dynamics moduli of soils with dynamic effect level.It is pointed out that Hardin and Drnevich's formula for determination of damping ratio underestimates damping ratio of soils when the dynamic effect level is lower than a certain value.Based on experimental data of dynamic moduli of three types of soils in Ying kou area,a mathematical relation which can satisfactorily fit the degradation of dynamics moduli is presented,and number of parameter in the relation is less than that in improved Hardin and Drnevich's hyperbolic relation and determination of the parameters is easy.Important influence of consolidation pressure on the degradation of dynamics moduli is studied and a method considering the influence is proposed.An improved formula to determine damping ratio which can satisfactorily fit the experiment data is presented.The dynamics moduli and damping ratio used in dynamics analysis of soil mass can be determined reasonably from mentioned results above,and reliability of the dynamics analysis results can be increased.
引文
[1]张克绪,谢君斐.土动力学[M].北京:地震出版社,1989.
[2]S普拉卡什.土动力学[M].徐攸在,译.北京:水利电力出版社,1984.
[3]F E小理查特,R D伍兹,J R小霍尔.土与基础的振动[M].徐攸在,译.北京:中国建筑出版社,1976.
[4]SEED H B,IDR ISS IM.SoilModu li and Damp ing fac-tors for Dynam ic Response Analyses,Repert No.EE-RC70-10[R].[s.l.]:Earthquake Engineering Re-search Center,Un iversity of Californ ia Berkeley,1970.
[5]HARD IN B O,DRMEVICH V P.Shear modu lus anddamp ing in soils:Design ing equations and curves[J].Jounal of the SoilM echan ics and Foundations D ivision,ASCE,1972,98:667-692.
[6]李咸享,吴志明,罗胜元,等.台北盆地动态参数之最佳化分析与验证[J].岩土工程学报,2001,(6):559-663.
[7]周敏锋,张克绪.一种水泥土非线性应力-应变关系研究[J].哈尔滨工业大学学报,2005,37(10):1400-1402.
[2]S普拉卡什.土动力学[M].徐攸在,译.北京:水利电力出版社,1984.
[3]F E小理查特,R D伍兹,J R小霍尔.土与基础的振动[M].徐攸在,译.北京:中国建筑出版社,1976.
[4]SEED H B,IDR ISS IM.SoilModu li and Damp ing fac-tors for Dynam ic Response Analyses,Repert No.EE-RC70-10[R].[s.l.]:Earthquake Engineering Re-search Center,Un iversity of Californ ia Berkeley,1970.
[5]HARD IN B O,DRMEVICH V P.Shear modu lus anddamp ing in soils:Design ing equations and curves[J].Jounal of the SoilM echan ics and Foundations D ivision,ASCE,1972,98:667-692.
[6]李咸享,吴志明,罗胜元,等.台北盆地动态参数之最佳化分析与验证[J].岩土工程学报,2001,(6):559-663.
[7]周敏锋,张克绪.一种水泥土非线性应力-应变关系研究[J].哈尔滨工业大学学报,2005,37(10):1400-1402.
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