筑坝土石料的变参数Ramberg-Osgood 模型及其适应性研究

被广泛采用的等价线性黏弹性模型不寻求土体动应力-应变的具体表达式，无法给出能量耗散函数，为深入研究筑坝土石料动力变形机制带来不便。变参数Ramberg-Osgood模型（简称R-O模型）通过变动两个参数以适应土体动模量衰减和阻尼增长，并给出滞回圈的数学表达式。研究中讨论了变参数R-O模型的适应范围，发现该模型不适合描述土体的小应变动力特性，给出了筑坝土石料变参数表达式，绘制了与试验曲线相协调的应力应变滞回圈。可以看出变参数R-O模型能够较好地描述筑坝土石料的动力特性，为进一步研究筑坝土石料的动力耗散与变形机制奠定了基础。

Ramberg-Osgood model with variable parameters of earth-rock materials for earth-rock dam and its adaptability

It is inconvenient for research the deformation mechanism of materials for earth-rock dam under dynamic loading using equivalent linear viscoelastic model, though it has been applied widely, because the stress-strain expressions haven’t been derived in this model and the energy dissipation don’t be described. In this paper, the Ramberg-Osgood constitutive model with variable parameters has been researched; and its adaptability has been discussed. It is found that the Ramberg-Osgood constitutive model is not applicable for describing the dynamic property of soil in small strain level. Also the expression of variable parameters is derived; the hysteretic loops have been drawn in different dynamic shear levels. A solid foundation has been established for studying the dynamic dissipation and strain mechanism of earth-rock dam materials.