软化与硬化特性转化的岩石损伤统计本构模型之研究

STUDY ON A STATISTICAL DAMAGE CONSTITUTIVE MODEL WITH CONVERSION BETWEEN SOFTENING AND HARDENING PROPERTIES OF ROCK

首先将在应力作用下的岩石材料抽象为破坏与未破坏两部分,并根据这两部分不同的受力情况,通过引进岩石材料屈服或破坏的能量原理,建立岩石损伤模型;其次,利用统计损伤理论,建立能够反映岩石破裂全过程的统计损伤演化方程,进而建立特定围压下的岩石损伤统计本构模型;最后,通过探讨模型参数与围压的经验关系,对模型进行合理修正,从而建立出反映不同围压条件下的岩石破裂全过程的统一三维损伤统计本构模型。该模型参数少,便于工程应用,尤其是它能够反映岩石软化与硬化特性随围压变化而相互转化的特征,与试验结果进行比较分析表明,该模型与实测结果吻合良好。

Firstly, rock material under stress is divided into two parts for yielded and unyielded material. According to the differences of these two parts under stress, a damage model for rock is established on the basis of it by introducing energy theory of yielding or failure for rock. Secondly, making use of statistical damage theory, a statistical damage evolution equation that reflects the full process of rock failure has been developed. A statistical damage constitutive model of rock under a specific confining pressure has been set up. At last, the model has been modified rationally by discussing the empirical relation between parameters of the model and confining pressure of rock. A unified three-dimensional statistical damage constitutive model applying to the condition of different confining pressure has been founded. It has less parameters and is simple and easy to apply, especially, it can also reflect characteristics about the conversion between hardening and softening mutually with the changing of the confining pressure. And its rationality has been shown compared with its test.