Stress–dilatancy theories play a central role in the modeling of the plastic dissipation of geomaterials. There exist several mathematical frameworks for describing the stress–dilatancy behavior of soils. One of the limiting assumptions often introduced is coaxiality between principal directions of stresses and plastic strain increments. However, experimental evidences suggest that this assumption is generally invalid for the deformation behavior of granular materials. In this paper, non-coaxial stress–dilatancy framework is developed first in axis symmetric, plane strain and then for general stress–strain conditions. To facilitate the use of the stress–dilatancy framework for cyclic loading conditions, loading and unloading are explicitly considered in the development of the framework. Furthermore, a possible way of establishing the evolution of the degree of non-coaxiality in plane strain and axis symmetric cases is presented. Then the approach is applied to selected yield functions.

中文翻译：

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岩土材料非同轴塑性耗散和应力-剪胀关系的公式化

应力-剪胀理论在土工材料塑性耗散的建模中起着核心作用。存在几种描述土壤应力-剪胀行为的数学框架。经常引入的限制假设之一是应力和塑性应变增量的主要方向之间的同轴度。但是，实验证据表明，该假设通常对粒状材料的变形行为无效。在本文中，首先在轴对称平面应变中开发了非同轴应力-剪胀框架，然后在一般应力-应变条件下开发了该框架。为了促进应力-剪胀框架在循环加载条件下的使用，在框架的开发中明确考虑了加载和卸载。此外，提出了建立平面应变和轴对称情况下非同轴度演化的可能方法。然后将该方法应用于选定的收益函数。