循环荷载下非饱和土的各向异性弹塑性双面模型

Anisotropic elastoplastic two-surface model for unsaturated soils under cyclic loading

在BBM模型及弹塑性双面模型的基础上,建立一个在静态及循环荷载作用下考虑非饱和土各向异性的弹塑性双面模型。在模型中引入反映各向异性的硬化参量,通过各向异性参量的初始值来反映初始各向异性,利用旋转硬化法则来描述循环加载过程中各向异性的变化规律。模型含有一个边界面和一个加载面,二者在应力空间中按照等向硬化、运动硬化以及旋转硬化法则来进行演化。同时,采用径向映射法则和移动的记忆中心来反映非饱和土的循环塑性特征。通过与相关试验数据的比较,模型可以较好地反映循环荷载下非饱和土的各向异性以及动态力学特征。

On the basis of the theory of BBM model and elastoplastic two-surface model,an elastoplastic two-surface model for unsaturated soils considering the anisotropy under static and cyclic loading is established.A hardening parameter reflecting the anisotropy is introduced in the model.The initial anisotropy is reflected by the initial value of the anisotropy parameter and the evolution of the anisotropy produced by cyclic loading is described by rotation hardening rule.The model contains a bounding surface and a loading surface,which evolve according to the isotropic hardening,kinematic hardening and rotational hardening rules in the stress space.Besides,radial mapping rule and mobile memory center are adopted to reflect the cyclic plastic characteristics of unsaturated soil.The comparison between experimental results and model simulations shows that the proposed model is capable of describing the anisotropy and dynamic mechanical behaviors of unsaturated soils under cyclic loading.