三向应力状态下单结构面岩石试样破坏机制与真三轴试验研究

Rock failure mechanism and true triaxial experimental study of specimens with single structural plane under three-dimensional stress

针对含结构面岩石的脆性破坏现象,探讨了三向应力条件下岩体破坏的单结构面控制效应。利用真三轴试验进行验证,系统研究了单结构面岩石试样在模拟工程岩体开挖卸荷与支护应力路径下的力学行为、结构控制规律及声发射(AE)特征等。研究表明,(1)三向应力下单结构面控制效应能够较好地描述工程岩体的结构控制规律和卸荷、支护作用,真三轴试验结果与理论分析较为吻合;(2)开挖卸荷与支护应力路径下,含结构面岩体的破坏模式、卸荷的影响和支护效果等均与应力状态、支护强度及结构面参数有关,可依据结构控制规律,从工程方位布置、提供合理支护等方面采取措施避免岩体发生结构控制破坏;(3)试样的AE活动和能量释放规律与完整试样相似,但结构面的存在降低了试样储能能力,且95%以上的应变能在破坏阶段突然释放。试验研究和结构面控制效应的探讨对地下工程岩体开挖支护有一定的指导意义。

Aiming at brittle failure of rock with structural plane, single structure plane controlling effect under three-dimensional stress is studied and verified by true triaxial experiments. The mechanical characteristics, structure controlling laws and acoustic emission （AE） characteristics of rock specimens with single structural plane is studied systematically, simulating the excavating and supporting stress path in engineering practice. The research indicates： （1） Single structure plane controlling effect under three-dimensional stress can describe the structure controlling laws, unloading and supporting effect of engineering rock well. True triaxial experiment results conform to the theory. （2） Under excavating and supporting stress path, the failure mode, unloading and supporting effect are all connected with stress condition, supporting strength and structural parameters. Therefore, methods as engineering orientation arrangement and proper support can be taken to prevent structure controlling failure. （3） The AE features and energy release laws are similar with intact specimens. However, the existence of structure reduces the strength and energy storage capability. Also, 95 % of the elastic strain energy is released during failure stage. The research can guide the excavation and supporting of engineering rock mass.