非饱和黄土结构性定量试验研究

非饱和黄土是典型的结构性土，对4种含水率的原状非饱和黄土和重塑非饱和黄土进行了3种围压下的三轴剪切试验。基于二元介质理论，通过原状非饱和黄土和重塑非饱和黄土的应力-应变曲线对比，定义了结构性参数结构应力分担比。考察了不同围压和含水率对结构应力分担比随应变变化的影响，并给出了其定量表达式。试验结果表明，围压和含水率是影响结构性的两个主要因素；随着应变增长，结构应力分担比分先线性增长后指数形式减低，其最大值可以表示成围压和含水率的函数。最后给出了考虑结构性的原状非饱和黄土本构模型的建模思路。

Experimental study of the structural parameter of unsaturated loess

Unsaturated loess is a typical structural soil. The triaxial shearing tests for four kinds water content intact unsaturated loess and remolded unsaturated loess under three kinds of consolidtation pressures were carried out. Based on the tests and the concept of geo-binary medium model, the stress share ratio as a quantitative parameter has been proposed to study the structure of unsaturated loess. The effect of consolidation pressure and water content are analyzed and the stress share ratio is described by a mathematic formula. Results show that the structure of loess is mainly affected by consolidation pressure and water content. The stress share ratio increases linearly then decreases exponentially with the increment of strain. Further the stress share ratio was applied to the constitutive model of intact unsaturated loess