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岩石裂纹起裂强度σci和损伤强度σcd的研究对探讨岩石渐进破坏过程和脆性破坏机制,建立岩石的起裂强度和长期强度准则具有重要意义。鉴于此,系统总结了岩石起裂强度和损伤强度的4种计算方法,包括裂纹应变模型计算法,声发射参数取值法,侧向应变、体积应变曲线观察法和移动点回归法,并以大理岩和花岗岩在单轴压缩条件下为例,详细描述了用不同方法计算σci和σcd时存在的问题。研究结果表明,裂纹应变模型法物理意义明确,可以方便和准确地确定岩石的σci和σcd;声发射撞击率可以定性或半定量了解岩石的渐进破坏和损伤过程,但无法准确定量确定σci和σcd;移动点回归法计算体积应变刚度时受取值点间隔影响较大,而且加载过程中不同阶段的特征并不明显,难以确定起裂强度值。研究结论可为加深对岩石裂纹起裂强度和损伤强度的重要意义的认识,了解两个强度值的计算方法并合理选取其计算方法提供有益的参考。
The research on rock crack initiation strength σci and damage strength σcd is of great significance in exploring the gradual failure process and the brittle failure mechanism of rock and establishing the rock rupture strength and long-term strength criterion. In view of this, four kinds of calculation methods of rock rupture strength and damage strength are systematically summarized, including crack strain model calculation method, acoustic emission parameter method, lateral strain, volume strain curve observation and moving point regression method. Taking the uniaxial compression of marble and granite as an example, the problems existing in calculating σci and σcd by different methods are described in detail. The results show that the method of crack strain model has definite physical meaning, and the σci and σcd of rocks can be determined easily and accurately. Acoustic emission impact rate can be used to understand the progressive failure and damage process of rock qualitatively or semi-quantitatively. However, it is impossible to accurately determine σci and σcd ; The moving point regression method to calculate the volumetric strain stiffness when the value of the point interval greater impact, and the load during the different stages of the characteristics are not obvious, it is difficult to determine the value of the initiation strength. The conclusion of the study can deepen the understanding of the significance of the crack initiation strength and the damage strength of rock, and to understand the calculation methods of two strength values and select the calculation method reasonably to provide a useful reference.