黄土的损伤及其演化规律研究

Q3黄土的应变软化特性可以用含损伤的本构方程来描述,结构性黄土的损伤变量及损伤演化规律的合理确定,对于正确判定黄土的结构损伤程度是十分重要的.试验研究表明,Q3黄土的损伤是受应力状态控制的,在简单加载条件下,导致损伤产生的应力门槛值随着含水量增加而线性减小,由刚度损伤和应力损伤假设所导出的损伤演化方程是一致的,它们都随着轴向应变的增加而增加.复杂应力条件下的黄土损伤演化方程的表现形式与简单加载条件下的完全相同,区别只是在于损伤参量的影响因素不同.按损伤理论计算的应力应变关系与试验值的对比说明,试验所推导的损伤变量表达式能较好的反映黄土应力损伤的特性.

Study on Damage of Loess and it's Evolution

Strain-soften character of Q3loess can be described by a constitutive equation with damage variable. To define reasonably the damage variable of loess and the damage evolution tendency is very important to the correct determination of the structure damage degree of loess. Experiment result shows that the damage of loess is controlled by stress state. The damage threshold of stress is decreasing linearly with the increase of water content. The damage evolution equation deduced by the hypothesis of rigidity degree damage is the same as that of strength damage,and the damages are increasing with the increase of axial strain. Although the expressional stress condition is the same as that in simple load form of damage evolution equation in complicated condition, the influence factors are different of the damage parameters. According to the comparison between the stress-strain relationship calculated by damage theory and that of experiment results, the damage equation deduced by experiment results in this paper will describe well the damage character of loess.