裂纹岩体贯通路径的有限元搜索

Finite element search on coalescence mechanism of cracks in rock mass

裂隙岩体在荷载作用下导致其内部裂纹的相互贯通,从而在裂纹尖端形成较大的塑性破坏区域,岩体工程的失稳大多是由于其内部节理、裂隙等缺陷发展导致的,应用断裂力学的方法,可以追踪岩体中节理裂隙的起裂、扩展至相互贯通使岩体局部破坏的过程,从而揭示岩体失稳的渐进破坏机制。应用有限元方法中的奇异单元模拟了岩体中不同倾角的压剪裂纹的破坏问题,根据不同倾角裂纹的力学机理分析了其受力差异,依据最短塑性区距离判据分析了相近裂尖的扩展距离,得出了不同倾角的两共线裂纹的破裂角及相近裂尖破坏后岩桥之间的有效距离。

The plastic zone of the crack tip is formed owing to the coalescence of inner crack in jointed rock mass under loading condition which leads to the instability of rock mass, the process of local damage owing to crack initiation, development, coalescence one another is tracked and the damage mechanics is posted in jointed rock mass by the method of fracture mechanics. In the paper, the fracture of compressive-shear crack of different angle in jointed rock mass is simulated by singular finite element method, and the mechanical difference is analyzed, the extended displacement of close crack tips is given by the judgment of mini-plastic zone displacement, and the effective displacement of rock bridge between con-liner close cracks tips after fracture is gained.