参数型岩石几何损伤模型的构建及其应用研究

Establishment and application of parametric geometrical damage model of rocks

岩石几何损伤模型是建立统计损伤本构模型的重要基础。在岩石变形力学特性基础上对现有岩石几何损伤模型进行了回顾性分析,针对它们难以较好地反映初始损伤特征和峰后变形破坏特征的缺陷与不足,首先,将岩石材料视为由未损伤部分、初始损伤部分和后继损伤部分组成,提出了考虑初始损伤的岩石几何损伤模型;然后,通过探讨Weibull分布参数m和F0对损伤变量变化产生的影响,构建了参数型岩石几何损伤模型,在此基础上建立了应变软化类岩石统计损伤本构模型并进行了修正,给出了模型参数的确定方法;最后,通过模型验证和参数分析表明,修正后模型能够较好地模拟岩石变形破裂全过程,参数λ和η对损伤变量变化产生的影响与m和F0等效,解决了现有岩石几何损伤模型存在的共性问题,该模型和方法具有一定的合理性和可行性。

The geometrical damage model of rocks is an important basis for the establishment of statistical damage constitutive model. Based on the mechanical properties of rock deformation, the existing geometrical damage models of rock are reviewed and these models have difficulties in considering the initial damage and post peak deformation failure characteristics. The rock mass is composed of the undamaged part, the initial damage part and the subsequent damage part, and a geometrical damage model of rocks considering the initial damage is proposed in this paper. The parametric geometric damage model of rocks is established by studying the influence of Weibull distribution parameters m and F0 on the variation of damage variable. Furthermore, a statistical damage constitutive model of rocks characterized by strain softening is established and modified, and the determination method of model parameters is given. The model verification and parameter analysis show that the modified model can better simulate the whole process of rock deformation and failure. The influences of parameters λ and η on damage variable are equivalent to m and F0, which solves the common problems of current rock geometric damage models. It demonstrates that the model and method in this paper are reasonable and feasible.