关键词: 裂纹扩展, 数字图像, 抽采钻孔, 时空规律

Abstract: o explore soft coal seam gas extraction in the process of drilling damage, the space-time characteristics of borehole specimen under uniaxial compression test, and measurement by digital speckle correlation method (DSCM) observation of crack initiation, extension, and through the whole process of temporal and spatial evolution characteristics, through the deformation feature point extraction, analysis of the crack tip space, time and regularity of crack.The results show that the upper (lower) end of the borehole and the left and right end of the far field all have tensile cracks, the left and right sides of the borehole have shear cracks, and the rest of the cracks are affected by both tensile stress and shear stress.The failure process of the sample can be divided into five stages according to the spatial and temporal evolution characteristics of the fracture. The macroscopic main crack is formed by the penetration connection between the left and right cracks around the hole and the left and right cracks in the far field.The spatial and temporal characteristics of the failure process of samples containing boreholes are closely related to the longitudinal and circumferential fractures that are prone to occur in the pressurized area of boreholes, which reveals the nature of the separation and complex fractures of boreholes and provides some reference for the study of the crack growth law around boreholes.