循环荷载下非饱和结构性黏土的弹塑性双面模型

非饱和黏土的结构性能够显著影响其力学特性。基于非饱和土经典模型BBM（Barcelona basic model）和一种可描述循环塑性的硬化法则，引入体积破损率的作为标准土体结构破损的参数，建立了一个描述常吸力下非饱和结构性黏土静态及动态力学特性的弹塑性双面模型。模型在应力空间中包含与重塑非饱和土屈服面几何相似的结构性边界面和加载面，采用径向映射法则和可移动的记忆中心原理，通过结构性边界面和加载面在应力空间中的演化来反映循环加载过程中非饱和结构性黏土的循环塑性特征和结构损伤过程。通过与相关非饱和黏土控制吸力试验数据的比较，表明该模型能够较好地反映静态加载下非饱和结构性黏土的力学特性，而模型预测的循环荷载下的应力?应变特征也具有一定的合理性。

An elastoplastic two-surface model for unsaturated structural clays under cyclic loading

The structure of unsaturated clays can significantly affect its mechanical properties. Based on the classical BBM (Barcelona basic model) and a hardening rule which can describe cyclic plasticity, an elastoplastic two-surface model is established to describe the static and dynamic mechanical properties of unsaturated structural clays under constant suction condition using the volumetric damage rate as the standard soil structural damage parameter. The proposed model includes a structural bounding surface and a loading surface which are geometrically similar to the yield surface of reconstituted unsaturated clays in the stress space. Based on the principle of radial mapping and movable memory center, the cyclic plastic characteristics and structural damage process of unsaturated structural clay under cyclic loading are reflected by the evolution of structural boundary and loading surface in stress space. By comparing with the relevant experimental results of unsaturated clays under controlled suction, it is shown that the model can well reflect the main mechanical behaviour of unsaturated structural clays under static loading, and the stress-strain behaviour predicted by the model under cyclic loading is also reasonable.