论文部分内容阅读
天然岩体中含有数量众多的裂隙且绝大多数为不等长裂隙,而那些具有一定尺度和规模的主控裂隙对岩体稳定性起决定作用。为研究不等长裂纹相互作用规律及主控裂纹起裂规律,基于Kachanov法,推导了远场受力的两条拉剪不等长共线裂纹的尖端应力强度因子表达式并从理论上分析了裂纹间距对裂纹相互作用的影响;通过最大周向应力准则,计算了单轴受拉时不同裂纹倾角的主控裂纹起裂角,绘出理论断裂准则曲线;推算滑动裂纹的应力强度因子,对含不等长裂纹的类岩试件进行单轴压缩试验。结果表明:当裂纹间距大于等于小裂纹长度时,小裂纹对主控裂纹的起裂几乎无影响;主控裂纹起裂角只与裂纹角有关,单轴受拉时,起裂角随裂纹角增大而减小,单轴受压时,起裂角随裂纹角增大而增大;当裂纹倾角小于30°时,起裂临界荷载急剧增大。
Natural rock mass contains a large number of fractures and the vast majority of cracks are not equal length, and those with a certain scale and size of the main control of rock stability plays a decisive role. In order to study the law of unequal length crack initiation and crack initiation, a Kachanov method was used to derive the tip stress intensity factor expression of two cohesion cracks with far-field forces and their theoretical analysis The effect of crack spacing on the crack interaction was studied. Based on the maximum circumferential stress criterion, the crack initiation angle of the crack with different cracks at uniaxial tension was calculated and the theoretical fracture criterion curve was plotted. The stress intensity factor of sliding crack was calculated, Uniaxial compression tests were carried out on rock samples with unequal length cracks. The results show that when the crack spacing is greater than or equal to the small crack length, the small crack has little effect on the initiation of the main crack. The crack initiation angle of the main crack is only related to the crack angle. When the single- And the crack initiation angle increases with the increase of crack angle under uniaxial compression. When the crack dip angle is less than 30 °, the critical load of cracking increases sharply.