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基于结构体损伤概念和非饱和土力学,利用边界面塑性理论,提出了一个可以描述循环荷载作用下非饱和土力学特性的弹塑性本构模型。在BBM(Barcelona Basic Model)模型的基础上,利用土的持水曲线建立了常含水率下吸力与土体应力之间的耦合作用关系;通过屈服面的大小的改变来反映土体结构性的变化,建立了与累积塑性应变相关的损伤规律。同时,修正了常用边界面理论中映射准则,引入可移动映射中心的概念,将加载、卸载过程的映射准则进行统一,以反映循环荷载下土体产生的滞回特性。通过与相关文献以及本文的循环三轴试验结果的比较,表明本文模型能够较好地模拟非饱和黄土在循环荷载作用下的力学特性。
Based on the concept of structural damage and unsaturated soil mechanics, an elasto-plastic constitutive model describing the mechanical behavior of unsaturated soils under cyclic loading is proposed by using the plastic theory of boundary conditions. Based on the model of Barcelona Basic Model (BBM), the coupling relationship between suction and soil stress under normal water cut is established by using soil water holding capacity curve. The change of yield surface reflects the structural property of soil Changes, established with the cumulative plastic strain-related damage laws. At the same time, the commonly used mapping theory in boundary surface theory is modified and the concept of movable mapping center is introduced. The mapping rules of loading and unloading processes are unified to reflect the hysteresis characteristics of soil under cyclic loading. Compared with the related literatures and the results of cyclic triaxial tests in this paper, the results show that this model can simulate the mechanical behavior of unsaturated loess under cyclic loading.