动荷载作用下辽西冻风积土的损伤演化分析

为了研究辽西冻风积土在动荷载作用下的损伤演化规律，采用动三轴仪进行了室内试验，获得了动本构关系、损伤演化方程以及损伤变量随应变的演化曲线。同时，针对冻风积土损伤的初始阶段，利用扫描电镜观测了微观结构。研究结果表明，冻风积土的损伤演化过程可以采用3个阶段进行描述。损伤的扩展速度在塑性损伤阶段发展较快，并且损伤变量的增长过程具备非线性特征；在微裂纹扩展阶段相对平缓，损伤变量与应变呈近似的线性增长关系。内部微裂纹的产生起于试样的中部，然后由中部向两端呈环状扩展。经过裂纹的交错和汇聚，斜向裂纹逐步形成和扩展。

Damage Evolution Analysis of Frozen Aeolian Soil in the West of Liaoning Province Under Dynamic Loading

Laboratory test has been done by using the dynamic triaxial test machine in order to study the damage evolution of frozen aeolian soil in the west of Liaoning Province under dynamic loading. The constitutive relation and damage evolution formula of frozen soil are established, and the dynamic evolution curve between damage variable and strain is sketched. At the same time, pertaining to the at initial stage of damage of frozen aeolian soil, the microstructure is observed by using the scanning electronic microscope (SEM). The results show that the process of damage of frozen aeolian soil can be divided into three stages. In plastic damage stage, the speed of damage growth is fast, and the increase of damage variable is non-linear. In micro-crack damage stage, the damage growth is relatively flat and smooth, and the relation between damage variable and strain is approximately linear. The interior micro-cracks appear in the middle of sample. From the middle to the ends of in the sample, the micro-cracks are in the from of circular growth. Through transfixion and collection of cracks, the inclined cracks come into being and enlarge step by step.