深埋大理岩脆性破裂细观特征分析

脆性材料的破裂过程与裂纹的扩展密切相关，其细观结构特征直接决定宏观力学行为表现，但目前受限于试验仪器，还无法完全把握脆性破裂的细观机制，必须将试验方法和数值方法有机结合。首先利用MTS完成大理岩的单轴和三轴压缩试验，并在试验过程中对声发射信号进行全程监测，利用获得的试验数据详细分析深埋大理岩破裂特征，明确内部裂纹的发展演化规律以及对大理岩宏观力学特性的影响。通过引入颗粒流程序(PFC)，借助于已经完成的单轴和三轴试验成果获得PFC计算中的颗粒参数和颗粒胶结面参数，利用BPM模型模拟脆性岩石的破坏。结果表明，PFC能够从细观尺度准确地再现深埋大理岩试验过程中的裂纹扩展和破裂特征，并且能够展现在实际试验过程中无法监测和获得的有价值的细观破坏特征，为描述脆性岩石的破裂特征和复杂力学行为提供可以依赖的描述方法。

MICROSCOPIC CHARACTERISTICS ANALYSIS OF BRITTLE FAILURE OF DEEP BURIED MARBLE

The failure process of brittle material is closely related to the propagation of crack. The microscopic structure characteristics directly determine the macroscopic mechanical behavior. But currently limited by the test instrument，the brittle failure mechanism can't be fully understood，and the test method must be combined with numerical method. Firstly，the uniaxial and triaxial compression tests were finished by mechnical testing system(MTS)，and the acoustic emission(AE) signal was monitored. According to the test data，the failure characteristics of deep buried marble were analyzed in detail and the development evolution law of internal cracks and its influence on macroscopic mechanical properties were made clear. Particle flow code was introduced，and the particle and cement parameters were confirmed by completed uniaxial and triaxial compression tests. The brittle failure of rock was simulated by bonded-particle model(BPM). The numerical simulation results show that the PFC can accurately reproduce the crack propagation and failure characteristics of deep buried marble and show the valuable microscopic mechanism that can't be monitored and obtained in the actual test process. The PFC method can be relied on to describe failure characteristics and complex mechanical behavior of brittle rock.