筑坝堆石料变参数R-O模型与阈值应变研究
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摘要
运用统计方法,给出了堆石料动剪模量比衰减及阻尼比增长的平均曲线表达式。建立了反映堆石料非线性和滞回性的变参数R-O模型,讨论了模型参数R,及参考剪应变的计算方法。推导了堆石料的增量耗散函数表达式,在热力学基本定律的框架下,研究了堆石料的屈服函数,讨论了其动力变形机理和第2阈值应变。对进一步认识筑坝堆石料动应力变形特性有一定意义。
The expressions for the mean curves of the attenuation of dynamic shear modulus ratio and the increase of damping ratio of rockfill materials are given by means of the statistical methods.A modified R-O constitutive model with variable parameters,which reflects the nonlinearity and hysteresis of rockfill materials,is established.The model parameters R,and reference shear strain are discussed.Based on the modified model,a dynamic dissipation incremental function is formulated.Then the corresponding yield surface and energy dissipation characteristics are analyzed based on the generalized thermodynamics,and the mechanism of dynamic stress-strain and the second threshold strain are discussed for rockfill dam materials.
The expressions for the mean curves of the attenuation of dynamic shear modulus ratio and the increase of damping ratio of rockfill materials are given by means of the statistical methods.A modified R-O constitutive model with variable parameters,which reflects the nonlinearity and hysteresis of rockfill materials,is established.The model parameters R,and reference shear strain are discussed.Based on the modified model,a dynamic dissipation incremental function is formulated.Then the corresponding yield surface and energy dissipation characteristics are analyzed based on the generalized thermodynamics,and the mechanism of dynamic stress-strain and the second threshold strain are discussed for rockfill dam materials.
引文
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[2]郭晓霞,迟世春,杨峻,等.基于热力学原理的土体动力模型阈值应变研究[J].水利学报,2008,39(9):1037-1044.(GUO Xiao-xia,CHI Shi-chun,YANG Jun,et al.Strainthreshold of dynamic model for soils based on generalizedthermodynamics[J].Journal of Hydraulic Engineering,2008,39(9):1037-1044.(in Chinese))
[3]栾茂田.土动力非线性分析中的变参数Ramberg-Osgood本构模型[J].地震工程与工程振动,1992,12(2):69-78.(LUAN Mao-tian.Ramberg-Osgood constitutive model withvariable parameters for dynamic nonlinear analysis of soils[J].Earthquake Engineering and Engineering Vibration,1992,12(2):69-78.(in Chinese))
[4]COLLINS I F,KELLY P A.A thermomechanical analysis of afamily of soil models[J].Géotechnique,2002,52(7):507-518.
[5]ZIEGLER H.The derivation of constitutive relations from thefree energy and the dissipation function[J].Advances inApplied Mechanics,1987,25:183-238.
[6]COLLINS I F,HOULSBY G T.Application ofthermomechanical principles to the modelling ofgeomaterials[J].Proceedings of the Royal Society of London(Series A),1997,453:1975-2001.
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