渗透压下岩石翼形裂纹应力强度因子及断裂判据

为研究渗透压下岩石翼形裂纹面部分闭合情况下的破坏行为,建立多裂纹间相互作用下压剪翼形裂纹的力学模型,推导得到岩石翼形裂纹尖端应力强度因子表达式.分析不同起裂角条件下,应力强度因子随岩石翼裂纹长度的变化规律,并对参数进行敏感性分析.基于摩尔-库伦准则,推导考虑裂纹间相互作用的部分闭合型裂纹的断裂韧度表达式,得到岩石在压剪应力作用下Ⅰ,Ⅱ型裂纹的复合断裂判据.分析结果表明:裂纹间相互作用对应力强度因子的影响效果显著;应力强度因子在起裂角为65°左右时达到最大;应力强度因子对裂纹起裂角和翼形裂纹长度较敏感,对裂纹闭合度的敏感性较小.

Stress Intensity Factors and Fracture Criterion of Rock Wing Cracks Under Pore Pressure

In order to discuss the damage of rock wing cracks under seepage pressure in partial closure conditions, a mechanical compression-shear wing cracks model is established with the mutual interaction of multiple cracks and the equation of stress intensity factor at the tip of the wing cracks is deduced. The variation of stress intensity factor with wing cracks length under different initial cracks angles is analyzed by comparing the sensitivity of parameters. Based on Mohr-Coulomb strength condition, the criterion of type Ⅰ and Ⅱ comprehensive cracks under compression and shear stress is obtained by the equation of closure cracks considering the interaction of different cracks. The results indicate that the influence of the cracks interaction and the stress intensity factor is significant and the stress intensity factor is maximum for 65° the initial cracks angle. The stress intensity factor is sensitive to the initial cracks angles and the cracks length, is not sensitive to the closure level of cracks.