【作者】 李地元； 李夕兵； 李春林；

【Author】 LI Diyuan~1,LI Xibing~1,LI C.Charlie~2 (1.School of Resources and Safety Engineering,Central South University,Changsha,Hunan 410083,China;2.Department of Geology and Mineral Resources Engineering,Norwegian University of Science and Technology,Trondheim 7491,Norway)

【机构】 中南大学资源与安全工程学院； 挪威科技大学地质与矿物资源工程系；

【摘要】 通过对Iddefjord花岗岩切片的微观结构分析发现,硬岩试样存在明显的微观缺陷和结构的非均质性。利用线弹性断裂力学方法,对单轴压缩下楔形滑移型裂纹的扩展规律进行了理论推导,得到了单裂纹条件下裂纹扩展的临界应力和裂纹初始长度、裂纹面倾角、摩擦角、岩石断裂韧度等之间的关系,并推导了压缩载荷和裂纹扩展长度之间的关系式,同时还分析了双轴压缩载荷作用下滑移型裂纹尖端翼裂纹扩展的应力强度因子和裂纹长度之间的关系。发现单轴压缩或较低围压情况下,微裂纹尖端较易形成平行于最大主应力方向的翼裂纹,最终可能在宏观上形成板裂破坏裂纹。更多还原

【Abstract】 Through observing the microscope photos of Iddefjord granite thin section,it is found that there are micro-defects and structural heterogeneity in the specimens.By using the linear elastic fracture mechanics method, the crack initiation and propagation along the wedge-shaped sliding fracture is deducted under uniaxial compression.The relationships between the crack initiation stresses and the initial crack length,crack dip angle, friction angle and fracture toughness of hard rocks are obtained.The relationship between the compression stress and the crack propagation length is calculated.The stress intensity factor of the crack tip is analyzed when the wing crack propagates under biaxial compression.It is concluded that under uniaxial compression or with low confining stresses,the parallel-σ₁ wing cracks will be generated along the micro-cracks and the spalling fractures may be formed from the point of macro view.更多还原