本文在伊万(Iwan)模型的基础上,提出了一个新的物理模型。新模型导出的应力-应变关系,骨架曲线的形状既可为加工硬化状,也可为加工软化状,且骨架曲线与滞回曲线的两个分枝可以相同,也可不同。而梅辛(Masing)型关系只是其中的一种特殊情况。根据该物理模型,对土在循环荷载作用下的剪应力-剪应变关系,提出了一个分析模型,目前常用的双曲线模型只是该分析模型的一个特例。最后还对读物理模型所代表的非线性系统在谐和外力作用下的稳态反应进行了讨论。 This paper proposes a new physical model based on the Iwan model. In the stress-strain relationship derived from the new model, the shape of the skeleton curve can be either a work-hardened shape or a processed softening shape, and the two branches of the skeleton curve and hysteresis curve can be the same or different. The Masing-type relationship is just a special case. According to the physical model, an analytical model is proposed for the shear stress-shear strain relationship of soil under cyclic loading. The currently used hyperbolic model is only a special case of the analytical model. Finally, the steady-state response of the nonlinear system represented by the reading physical model under harmonic and external forces is also discussed.