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该文根据复合材料均匀化理论的思想建立了考虑水的滞后性与应力-应变特性相耦合的非饱和原状土本构模型。复合材料均匀化理论的主要思想是将变形的岩土材料视为由相对完整状态土(RISP)和完全调整状态土(FASP)混合而成的复合材料,RISP和FASP的力学性能分别与原状土和重塑土的力学性能相同。另外,在土体的变形过程中,RISP将逐渐转变成FASP,故二者的变形特性应分别采用不同的本构模型描述。该文则分别采用了弹性和弹塑性本构关系描述,土材料的总体应力-应变本构关系即可通过均匀化理论得到。该文对水滞后性的描述则采用了Wei给出的边界面模型。非饱和原状土结构性的退化采用扰动变量D来描述,该文已给出了其随变形变化的演化规律。该文模型共有16个参数,其中新引入的结构性参数衰减指数α和峰值因子β则主要描述了结构性对土材料力学性能的影响,该文对二者的影响分别进行了分析。通过对比模型预测结果和实验结果以及结构性参数分析发现,该模型能够较好的描述非饱和原状土的应力-应变特性,尤其是应变软化现象,且所给出的扰动变量演化规律也能够较好的描述土结构性的退化规律。
According to the theory of homogenization of composites, a constitutive model of unsaturated undisturbed soil considering the relationship between water hysteresis and stress-strain characteristics is established. The main idea of the homogenization theory of composites is that the deformed geomaterials are treated as a composite material composed of relatively intact soil (RISP) and fully tuned soil (FASP), and the mechanical properties of RISP and FASP are respectively compared with undisturbed soil The same mechanical properties and remodeling of soil. In addition, in the process of soil deformation, RISP will gradually transform into FASP, so the deformation characteristics of the two should be described by different constitutive models respectively. In this paper, the elastic and elastic-plastic constitutive relations are respectively used to describe the overall stress-strain constitutive relation of soil materials, which can be obtained by the homogenization theory. The paper describes the water hysteresis using the boundary surface model given by Wei. The structural degradation of unsaturated undisturbed soil is described by perturbation variable D, and the evolution law of its deformation with deformation has been given. There are 16 parameters in this paper. The newly introduced structural parameter attenuation index α and peak factor β mainly describe the effect of structure on the mechanical properties of soil materials. The paper analyzes the effects of the two on soil materials. By comparing the prediction results with the experimental results and the analysis of structural parameters, it is found that this model can well describe the stress-strain behavior of unsaturated undisturbed soil, especially the strain softening phenomenon, and the evolution law of the disturbance variables can also be compared Good description of the structural deterioration of soil laws.