基于数字图像的复合岩石试验与损伤模型研究

为研究层状复合岩石破坏过程和形态,采用相似理论制作出层状复合岩石相似模型,在单轴压缩条件下观测岩石的破坏特征,结合三维数字图像相关技术(3D Digital Image Correlation,以下简称DIC)对试件的整体变形及破坏进行全过程的观测,得到复合岩石三维场的位移和应变,同时基于试件表面应变场的变化,建立了表面损伤程度与损伤因子D之间的量化关系,进而得到基于DIC表征的层状复合岩石损伤演化模型,研究结果表明：(1)层状复合岩石的破坏形态与脆性岩石特征相似,以拉伸劈裂破坏和Y型剪切破坏为主；(2)DIC试验记录的表面应变与损伤因子之间的量化关系可有效反应岩石破坏的全过程,以此为基础建立的损伤演化方程与实验数据拟合效果较好,证明了模型的合理性。

Study on Composite Rock Test and Damage Model Based on Digital Image

In order to study the failure process and morphology of layered composite rock, the similarity model of layered composite rock was made by using the similarity theory. The failure characteristics of rock were observed and tested under uniaxial compression. Combined with the three-dimensional strain measurement system (DIC), the whole process of overall deformation and failure of the samples was observed, and the displacement and strain of three-dimensional field of composite rock were obtained, At the same time, based on the change of sample surface strain field, the quantitative relationship between surface damage degree and damage factor D was established, and then the damage evolution model of layered composite rock characterized by DIC was obtained. The research results show that: (1) The failure mode of layered composite rock is similar to that of brittle rock, mainly tensile splitting failure and Y-type shear failure. (2) The quantitative relationship between surface strain and damage factor recorded by DIC test can effectively reflect the whole process of rock failure. Based on this, the damage evolution equation established has a good fitting effect with the experimental data, which proves the rationality of the model.