基于最大拉应变理论的岩石损伤机理

以岩石内部微元体为研究对象,研究了在宏观应力作用下微元体的应力分布特点.将微元体应力的分布按正态分布考虑,结合最大拉应变强度准则,提出岩石微元体破坏的控制条件是最大拉应变.据此建立了微元体的三种破坏方式,研究了不同破坏方式对岩石承载能力的影响,推导出各破坏方式发生的条件及概率,并将微元体的三种破坏与三个方向的损伤因子联系起来,实现了细观与宏观的结合.在此基础上,建立了考虑各向损伤异性的岩石损伤本构模型,推导了参数的求解方法.最后对该模型的合理性进行了验证,发现利用该模型能够很好地解释不同应力条件下岩石的破坏方式以及围压对岩石峰值强度和残余强度的影响规律.

Rock damage mechanism based on the maximum tensile strain

The micro unit inside the rocks was investigated for the characteristics of stress distribution of the micro unit under macro stress effect and the stress distribution of the micro unit was considered as a normal distribution.At the same time,with the maximum tensile strain rules and control condition of micro unit damage(maximum tensile strain),three modes of micro unit damage were established in order to study the effects of different modes on load bearing capacity.The condition and the ratio of all the modes were deducted and the micro and the macro factors were combined by connecting all the three damage modes and the damage factors.Based on this,a constitutive mode of rock damage was built by considering all kinds of variations and the resolution of the parameters was derived.Finally,a test on the rationality of this mode showed that the mode could be well suited to explain all the rock damage modes under different conditions,the intensity of ambient pressure on the peak value as well as the impact laws of the residual strength.