对含交叉裂隙相似材料试件进行单轴压缩试验,用Abaqus对含交叉裂隙节理岩体进行应力分析,研究了含交叉裂隙节理岩体单轴压缩下的破坏机制。结果表明:交叉裂隙的主裂隙与加载方向呈30°、45°时,主裂隙是裂隙扩展及破坏的控制裂隙,此时含交叉裂隙岩体强度高于含单向裂隙岩体,是由于主裂隙裂尖最大环向应力σθmax低于单向裂隙;主裂隙与加载方向呈0°或90°时,次裂隙是控制裂隙;主裂隙与加载方向呈0°时,大部分次裂隙裂尖σθmax及裂尖最大应力强度因子KⅡmax高于单向裂隙,因此,此时大部分含交叉裂隙岩体强度低于含单向裂隙岩体;在主裂隙与加载方向呈90°工况组中,主、次裂隙夹角为45°时,次裂隙裂尖KⅡmax最大,所以此工况组中此时强度最低。
The uniaxial compression failure mechanism of jointed rock mass with cross-cracks was studied through similar material uniaxial compression tests and numerical computation with Abaqus. The study results show that when the angle between the main crack and loading direction is at 35° or 45°, the main crack is the key crack of crack propagation and rock mass failure. At these cases the strength of rock mass with cross-cracks is higher than that of rock mass with single crack. The reason is that the maximum hoop stressσθmax of main crack tip is less than that of single crack. When the angle between the main crack and loading direction is at 0°or 90° the secondary crack is the key crack of crack propagation and rock mass failure. When the angle between the main crack and loading direction is at 0° the maximum hoop stressσθmax and the maximum stress intensity factor KⅡmax of most secondary cracks are higher than those of single crack. So at these cases the strength of rock mass with cross-cracks is lower than that of rock mass with single crack. The KⅡmax of the case with 45° between main crack and secondary crack is the maximum stress intensity factor in those cases that the angle between the main crack and loading direction is at 90°. So the strength of rock mass with 45° between main crack and secondary crack is the lowest one in this case group.