循环荷载饱和风积土累积塑性变形模型

Cumulative Plastic Deformation Model of Cyclically Loaded Saturated Aeolian Soil

为了研究在不同初始静偏应力、动应力和围压作用下累积塑性应变变化规律,采用GDS三轴试验系统对饱和风积土进行不排水动三轴试验;并结合现有饱和土体累积塑性变形模型和疲劳损伤模型理论,建立一种新的循环荷载饱和风积土累积塑性变形预测模型;通过与试验数据进行对比,验证了所建立模型的正确性,进而揭示饱和风积土在循环荷载作用下的疲劳损伤和损伤与累积塑性应变之间的变化规律。结果表明:在相同动力幅值作用下,累积塑性应变随着静偏应力增大而增大,其应变增长速率也越大;同时,曲线变形趋于稳定时对应的循环次数也越大。模型曲线与试验数据具有良好的吻合度,证明了该模型可更好地分析在循环荷载作用下土样的动力特性,也可进一步分析土样的损伤演化规律和疲劳损伤变化规律,为路基土的动力灾害治理提供理论依据。

In order to study the cumulative plastic strain change law under different initial static deviator stress,dynamic stress and confining pressure,the GDS triaxial test system is used to conduct undrained dynamic triaxial test on saturated aeolian soil.And by combining the existing saturated soil body cumulative plastic deformation model and fatigue damage model theory,a new cyclic load saturated aeolian soil cumulative plastic deformation prediction model is established.By comparing with experimental data,the correctness of the established model is verified.Furthermore,it reveals the law of change between fatigue damage and damage and cumulative plastic strain of saturated aeolian soil under cyclic loading.The results show that under the same dynamic amplitude,the cumulative plastic strain increases with the increase of static deviator stress,and its strain growth rate also increases.At the same time,when the curve deformation tends to be stable,the corresponding cycle times are also larger.The model curve is in good agreement with the experimental data.This proves that the model can better analyze the dynamic characteristics of soil samples under cyclic loading,and we can also analyze the law of damage evolution and fatigue damage of soil samples in one step.This provides a theoretical basis for the dynamic disaster management of subgrade soil.