Abstract The constitutive model for frozen soils is one of the hot research topics in the frozen soils mechanics. In this paper, the loading-unloading-reloading tests are carried out with different confining pressures to further investigate the deformation characteristics for frozen soils, and it is found that the elastic and plastic deformation of frozen soils do not occur simultaneously in the shear process, which demonstrates that this two types of deformations have different physical mechanisms. Then these two deformation mechanisms are studied under the framework of breakage mechanics for geomaterials by taking the ice-cementing part as the bonded elements (Elastic characteristic) and breakage part as the frictional elements (Plastic characteristic) in frozen soils. Based on the above results, the binary medium constitutive model for frozen soils is derived with the homogenization theory, considering this breakage mechanisms and the nonuniform distribution of stress. Meanwhile, a more reasonable methods for obtaining the evolution functions of breakage ratio and stress concentration tensor are presented. Finally, the parameters of this binary medium model are determined through experiments to duplicate the test curve of frozen soils, and the computed results demonstrate that the constitutive model proposed here can well simulate the deformation characteristics of frozen soils.

中文翻译：

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饱和冻土弹塑性二元介质本构模型

摘要 冻土本构模型是冻土力学研究的热点之一。本文通过不同围压下的加载-卸载-再加载试验进一步研究了冻土的变形特性，发现在剪切过程中冻土的弹塑性变形不是同时发生的，这表明这两种变形具有不同的物理机制。然后在土工材料断裂力学框架下,以冰固部分为粘结单元(弹性特性),断裂部分为摩擦单元(塑性特性),在冻土中研究了这两种变形机制。根据以上结果，考虑到这种破坏机制和应力的非均匀分布，采用均质化理论推导出冻土的二元介质本构模型。同时，提出了一种更为合理的获取断裂率和应力集中张量演化函数的方法。最后，通过实验确定了该二元介质模型的参数，复制了冻土的试验曲线，计算结果表明本文提出的本构模型能够很好地模拟冻土的变形特征。提出了一种更合理的获取断裂率和应力集中张量演化函数的方法。最后，通过实验确定了该二元介质模型的参数，复制了冻土的试验曲线，计算结果表明本文提出的本构模型能够很好地模拟冻土的变形特征。提出了一种更合理的获取断裂率和应力集中张量演化函数的方法。最后，通过实验确定了该二元介质模型的参数，复制了冻土的试验曲线，计算结果表明本文提出的本构模型能够很好地模拟冻土的变形特征。