中文摘要：

岩石表面裂隙是造成岩体缺陷的重要因素。以红砂岩制作标准岩石试件,通过单轴压缩、实时监测、CT扫描和数值分析方法,分析不同张开度表面裂隙试件裂纹三维扩展模式及其物理力学性质。研究表明：单轴荷载下,表面裂隙从内部开始扩展,并逐渐延伸至试件表面;在试件内部,裂纹面包裹在预制裂隙周边,主要沿最大主应力方向扩展,并在边界的影响下逐渐向试件表面靠近;表面裂隙张开度越小,其扩展方向受边界影响越大;随表面裂隙张开度增大,岩石的峰值强度、峰值应变和弹性模量均变小;数值分析发现,受边界影响,预制裂隙周边的应力影响带向表面倾斜,成为导致裂纹扩展路径向试件表面靠近的重要因素。

英文摘要：

Rock surface crack is an important contributing factor of rock defect.Uniaxial compression test,real-time monitoring,CT scan and numerical analysis were carried out to analyze the three-dimensional crack extension mode of different opening surface crack and the physical-mechanical property of the standard rock specimen prepared from red sandstone.The research shows that,under uniaxial load,the extension of surface crack starts from the inside and gradually extends to the specimen surface.Wrapped in the rim of the prefabricated crack,the internal crack extends along the direction of maximum principal stress and gradually approaches to the specimen surface under the influence of boundary.The smaller the surface crack opening,the greater the boundary effect on the extension direction.With the increase of the surface crack opening,the rock peak strength,peak strain and elastic modulus become smaller.Numerical analysis shows that,influenced by the boundary,the stress influence zone of the prefabricated crack rims inclines to the surface,resulting in the approach of crack extension path to the specimen surface.