A NEW MODEL FOR UNSATURATED SOIL USING SKELETON STRESS AND DEGREE OF SATURATION AS STATE VARIABLES
A NEW MODEL FOR UNSATURATED SOIL USING SKELETON STRESS AND DEGREE OF SATURATION AS STATE VARIABLES
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DOI：
10.3208/sandf.51.67
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发表时间：
2011-02
影响因子：
3.7
通讯作者：
Feng Zhang;Tomoyuki Ikariya
中科院分区：
文献类型：
--
作者：
Feng Zhang;Tomoyuki Ikariya
本文在试验结果的基础上，提出了以骨架应力和饱和度为独立状态变量的非饱和土本构模型，该模型能较好地描述饱和度的影响。在该模型中，还提出了一种非常简单的考虑非饱和土水分滞后的水分特征曲线。水分特征曲线不仅适用于二次干燥过程，也适用于淤泥质土的一次干燥过程。该本构模型不仅能描述非饱和土体的特性，而且还能描述饱和土体的本构关系，因为当饱和状态从非饱和状态变为饱和状态时，骨架应力可以平稳地转变为有效应力。同时，还考虑了饱和土模型中讨论的土体的主要特征之一--超固结，并与饱和度一起考虑。在本研究的框架内，可以很容易地将土的结构和应力引起的各向异性等其他力学特征纳入到所提出的模型中。通过模拟可知，在不同的围压和吸力条件下，非饱和土的各向同性固结试验和排水、耗竭条件下的三轴压缩试验的主要特征可以定性地描述。
In this paper, based on experimental results a new constitutive model, using skeleton stress and degree of saturation as independent state variables, is proposed for unsaturated soil, in which the influence of the degree of saturation can be properly described. In the model, a very simple moisture characteristics curve considering moisture hysteresis of unsaturated soil is also proposed. The moisture characteristics curve can not only be applied to secondary drying process but also primary drying process originated from slurry soil. The constitutive model is able to describe not only the behavior of unsaturated soil but also saturated soil because the skeleton stress can smoothly shift to effective stress if saturation changes from unsaturated condition to saturated condition. Meanwhile the overconsolidation, one of the main features of soils that are discussed in the models for saturated soils, is also considered together with the degree of saturation. Other mechanical features such as structure of soil and stress-induced anisotropy can be easily incorporated into the proposed model within the framework of the present research. It is known from the simulation that the main features of unsaturated soil in isotropic consolidation test and triaxial compression test under drained and exhausted condition with different confining stress and suction can be qualitatively described.