单轴压力作用下岩石破坏机理分析与应用

ANALYSIS AND APPLICATION OF ROCK DAMAGE MECHANISM UNDER UNIAXIAL COMPRESSION

单轴压力作用下,从微观出发,岩石破坏是由体内微裂纹中的拉应力所致,如果出现类似于剪切破坏的情况,可近似地认为是试件端部与实验台之间的摩擦力所致。本文采用宏观方法,应用弹性力学和应力叠加原理相组合,从变形协调角度出发,得出试件内部不存在拉应力;用数值模拟物体的单轴压力状态仍然没有拉应力。由此提出,最大伸长理论也同样能解释在单轴压力作用下岩石的破坏。并且推导出在围压达到临界围压时岩石的破坏转变为剪切破坏。

With microscope methods the conclusion obviously come out that under uniaxial compression rock is damaged by the inner tensile stress. If under the same condition rock is damaged by shear stress, we think it arise from the friction between rock and experiental machine. In terms of macroscope methods, with elastic mechanics, superposion principle and coordination condition of deformation, no tensile stress exists in rock. With the finite element method no tensile stress appear in mass under uniaxial compression. So maximum extended deformation can explain the rock＇s damage under uniaxial compression. And the critical confining stress is figured out and stress＇s reaching the critical confining stress, rock will be damaged by shear stress rather than extended deformation.