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。
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.