基于应力空间变换的原状软土本构模型

根据原状土的高刚度、明显的非线性和各向异性特点，给出了原状土的应力空间和应力增量变换公式。在变换应力空间，屈服面、边界面只能在允许的应力空间中运动(等向硬化或运动硬化)，从而合理地反映了土体各向异性与应力路径的影响.借助边界面与损伤的概念建立了可以反映原状软土从小应变到大应变的力学特性的本构模型.土体弹性变形用横观各向同性模型来描述，提出了一种新的边界面与加卸载准则，它同时考虑了塑性体应变与塑性剪应变对原状土体结构性的损伤.与有关试验结果对比表明，本模型是合理的。

Constitutive model for natural soft clay based on transformation of stress space

The concept of stress space transformation is introduced to describe the stress-strain state of the soil. The formulas for transformation of stress space and stress increment are established. The movement of yield surface and boundary surface (isotropic hardening or kinematics hardening) is limited in the allowable stress space. The stress-induced anisotropy and the influence of stress path are reasonably considered in the transformed stress space. Based on the boundary surface theory and damage theory, a consitutive model simulating the mechanical behavior of natural soft clay changing from small strain to large strain is proposed. A simple loading-unloading criterion is suggested. The effects of plastic volumetric strain and plastic distortional strain on degradation of structure are considered. The validity of the proposed model is verified by experimental results.