Two classifications of gradient plasticity theory and their differences are introduced. Subsequently, the general constitutive relation of gradient plasticity theory is established by introducing the gradient term of hardening parameter into material' s yielding function. Considering the particularity of rock material, a gradient plastic model with plastic bulk strain as internal variable is established by introducing its gradient term to Drucker-Prager yield model. The expression of plastic bulk strain is presented based on the classical plasticity theory, and the increment constitutive relation of rock' s strain localization is derived. At last, rock' s strain localization in uniaxial stress is analyzed in the condition of the plane strain. As a result, the expression of the strain localization band width is deduced, and the band width variation when the localization band parameter changes is derived.%首先介绍了2种基本类型的梯度迥性理论以及两者间的差别,然后在材料的屈服函数中考虑硬化参数的梯度项,引入了梯度塑性理论的一般本构关系.考虑到岩石材料的特殊性,以塑性体积应变为内变量,在Drucker-Prager屈服模型中引入该内变量的梯度项,建立了岩石的一种内变量梯度塑性模型；在经典塑性理论基础上推导了塑性体积应变的表达式,得出了分析岩石应变局部化的增量本构关系.最后在平面应变状态下分析单向受力时岩石应变局部化状态,推导出了应变局部化带宽度的表达式,并且得出了带宽随局部化带参数变化而变化的结论.
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