恒应变率下的岩石三轴动态变形过程模拟方法

针对岩石动态变形特点,首先引进Kelvin模型研究思路与方法,将岩石变形过程中的动态应力视为静态应力分量与动态应力分量的叠加,分别以黏性元件和非线性元件模拟岩石单元的动态应力分量与静态应力分量,并建立出岩石动态应力的力学分析模型;然后在此研究基础上,利用黏性元件的力学特性和统计损伤理论分别建立出黏性元件和非线性元件变形过程模拟方法,进而得到岩石三轴动态变形过程模拟方法,并提出其模型的参数确定方法;最后通过实例分析与讨论,表明该模型不仅能反映岩石动态变形过程的应变软化特性,而且能较好地反映加载速度或应变率对岩石三轴动态变形过程的影响,具有较强的合理性和可行性。

Simulation method of dynamic triaxial deformation process for rock under invariable strain rate

Firstly, according to the dynamic deformation characteristics of rock and based on the Kelvin model, a mechanical model to simulate dynamic behavior of rock is established by treating dynamic stress of rock in the deformation process as the summation of two components, which are the static stress and the dynamic stress component. The viscous and the nonlinear elements in the model are used to simulate the above two components, respectively. Secondly, dynamic simulation methods of the deformation process of the viscous and the nonlinear elements are obtained according to the mechanical characteristics of the viscous element and the statistical damage theory, consequently, a method to simulate the tri-axial dynamic deformation process of rock is proposed, and the corresponding method to determine the relative parameters is proposed as well. Finally, a practical example is employed to verify the feasibility of the presented model. The analytical results indicate that the proposed constitutive model can describe the characteristics of strain softening and reflect the influence of strain rate on the dynamic deformation process of rock.