中文摘要：

为了获取冻风积土在循环逐级加载过程中发生的动力损伤特征,通过对不同负温、围压及振动频率条件下的冻风积土试样进行动三轴试验,测得其动应力-应变曲线。按照冻风积土发生各向同性损伤及塑性应变增量垂直于屈服面的基本假设,利用塑性势函数F（Y,D,σ）相关联流动法则并按照R-O硬化定律建立了冻风积土加载过程中塑性损伤演化模型（P模型）。利用文中提出的有效应力分析方法对试验所测得总动应变中所包含的累积塑性变形部分进行分离,实现了对P模型中参数拟合的目标;根据一、三主应力对D-P屈服边界进行划分以确定加载过程中弹塑性变形特征。通过分析裂隙发展规律研究冻风积土内部塑性损伤演化过程,将累积塑性变形变化率曲线的拐点作为冻风积土发生塑性损伤的阈值,给出了确定初始发生塑性损伤的理论依据。研究结果表明：P模型与相关文献模型确定的塑性损伤变量变化规律具有一致性,为冻风积土路基或基础的动力灾害防治研究提供理论基础。

英文摘要：

In order to obtain the dynamic damage characteristics of the frozen aeolian soil in the process of cyclic loading, the dynamic stress-strain curve of the frozen soil samples under different negative temperatures,confining pressures and vibration frequencies is measured by dynamic triaxial test. According to the basic assumption that the isotropic damage and the plastic strain increment of frozen aeolian soil is perpendicular to the yield surface,the plastic damage evolution model（ P model） of the soil in the loading process is established according to the law of R-O hardening by using the associated flow rule about the plastic potential function F（ Y,D,σ）. By using the proposed effective stress analysis method,the cumulative plastic deformation part of the total strain measured is separated,and the target of the parameter fitting in the P model is realized. The D-P yield border is divided by 1st and 3rd principal stresses to determine the elastic and plastic deformation characteristics in the process of loading. By analyzing the rule of fracture development,the plastic damage evolution process in frozen aeolian soil is studied,the inflection point of the cumulative plastic deformation rate curve is taken as the threshold of the plastic damage of the frozen aeolian soil,and the theoretical basis for determining the initial occurrence of plastic damage is given. The result shows that the change of the plastic damage determined by P-model is consistent with that determined by the relevant literature model,which provided a theoretical basis for the study of the dynamic disaster prevention and control of frozen aeolian soil subgrade or foundation.