基于经典连续体的Duncan- Chang 模型缺少用于表征材料破坏程度的参数及与应变局部化带宽相关的特征长度，且无法反映材料的软化特性．为此，基于扰动状态概念，引入Cosserat 连续体理论作为正则化机制，以Duncan- Chang 模型描述相对完整状态下材料的响应，以临界状态模型描述完全调整状态下材料的力学行为，并分别基于常规三轴试验曲线与体积应变阈值、形状改变能极限状态概念提出两种扰动因子演化方式．利用数值算例考察了扰动对材料承载力、应变局部化行为的影响．模拟结果表明: 两种演化方式均能描述材料的软化特性，第二种方式在预测剪破角变化规律方面更为合理; 所发展的扰动状态模型在模拟应变局部化问题时可以在一定程度上消除对有限元网格密度的敏感性．

Duncan- Chang model based on classical continuum theories cannot reflect the softening behavior ofgeotechnical materials and it lacks the parameters describing the failure of materials and the internal length scale re-lated to strain localization.In order to solve this problem,on the basis of the disturbed state concept and by intro-ducing the Cosserat continuum theory as a regularization mechanism,the response of materials in relative intactstate is described with the Duncan- Chang model,the mechanical behavior of materials in fully adjusted state ischaracterized with the critical state model,and two disturbance evolution modes,one of which is based on the volu-metric strain threshold as well as the conventional triaxial test curves and the other is based on the limit state of de-viator strain energy,are presented.Moreover,some numerical examples are given to reveal the effects of distur-bance on the bearing capacity and the strain localization behavior.The results show that both of the two disturbanceevolution modes well describe the softening behavior of materials,the latter mode is more reasonable than the formerin terms of the inclination angle prediction of shear band,and the developed disturbed state model above helps toreduce the mesh density- dependence of the results to a certain degree when it is used to simulate the strain localiza-tion phenomenon.