单轴拉伸作用下岩石裂隙起裂扩展的数值模拟

Numerical simulation of initiation and propagation of rock cracks under uniaxial tension

地下采矿工程开挖对天然岩石是一种卸荷行为,卸荷后的岩石容易受到拉应力作用,造成岩石内部原生裂隙的扩张贯通,从而极大影响工程岩体稳定性。为研究拉伸作用下岩石内部裂隙的萌生演化规律,采用扩展有限单元法,对含不同裂隙倾角的岩石进行了模拟研究。结果表明:拉伸应力下岩石裂隙起裂主要受Ⅰ型应力强度因子控制,裂隙倾角越大,起裂越困难,相应的起裂角也越大;裂隙扩展时的扩展角保持不变,扩展方向与最大拉应力方向保持垂直。

Underground mining will result in the release of load from natural rocks. They afterwards are subjected to tensile stress,leading to primary crack growth and even cut-through inside the rocks which have a detrimental effect on the stability of the engineered rock mass. In order to study the rules of initiation and evolution of cracks in rocks under tension,Extended Finite Element Method is used to simulate the rocks containing different cracking angles. The results show that the initiation of cracks is mainly controlled by mode I stress intensity factor; the larger the angle of cracks,the larger the initiation angle and the more difficult the initiation; and the propagation angle remains fixed and the direction of crack propagation keeps vertical with the largest tensile stress direction as the crack grows.