应用数字散斑相关方法实验研究雁列断层变形破坏过程

An experimental study of the failure process of en-echelon fault structure using the digital speckle correlation method

以数字散斑相关方法(DSCM)为观测手段,对雁列断层结构的破坏过程进行了实验研究,观测和分析了变形破坏过程中模型表面的变形场演化过程.断层结构由一块含两条平行割缝的大理岩平板模拟,模型试件在双轴试验机上加载;DSCM观测系统在加载过程中记录试件表面的散斑图像,然后分析得到模型表面待测区域各记录时刻的位移场及应变场.全场连续的变形数据清晰地反映了雁列断层结构的变形破坏过程的各种细节.实验结果显示,变形最初集中在断层带周围,然后迁移到雁列区,最后雁列区贯通,结构发生滑动导致整个结构发生失稳破坏.对变形破坏过程中的变形场进行统计分析发现,一种描述变形局部化特征的统计指标—Cv值,可以作为一个雁列断层破坏的前兆指标.

The failure process of en-echelon fault structure is experimentally studied and the evolution of the deformation filed during failure is inspected and analyzed using the digital speckle correlation method （DSCM）. The fault structure is simulated by a marble plate with 2 parallel slits that firstly cut and then filled with gypsum. The specimens are loaded on a large-scale double-axis test machine. The DSCM system captures speckle images during the test process and then processes them to obtain deformation field. The whole failure process of the echelon fault structure is revealed by evolution of the deformation field. The result shows that the deformation is firstly localized around the fault and then the echelon area, where the two faults are interactive with each other. The failure also finally evolves in this echelon area. Moreover, the deformation field during loading is statistically studied and a quantitative Cv-value, which expresses the characteristics of deformation localization, is an indicator for the failure of the echelon fault structure.